Arylazo-glycenosides. Part 8. Synthesis and reactions of some 2- and 3-arylazo-derivatives of methyl 4,6-O-benzylidene-2,3-dideoxy-D-threo-hex-2-enopyranosides

摘要

J. CHEM. SOC. PERKIN TRANS. I 1983 Arylazo-glycenosides. Part 8.' Synthesis and Reactions of Some 2-and 3-Arylazo-derivatives of Methyl 4,6-0-Benzylidene-2,3-dideoxy-D-threo-hex-2-enopyranosides Neeta Dang, V. Ranjith N. Munasinghe, and W. George Overend * Chemistry Department, Birkbeck College (University of London), Malet Street, London WCI E 7HX Preparations are described of the a-and P-anomers of methyl 4,6-0- benzylidene-2,3-dideoxy-2-phenyl-azo-D-threo- hex-2-enopyranoside and of methyl 4,6-0- benzylidene-2,3-dideoxy-3-phenylazo-a-D-threo- hex-2-enopyranoside using D-galactose as the initial material. The procedures adopted for the syntheses are essentially those developed in our laboratory for the preparation of phenylazo-derivatives of sugars, as described in Part 1 of this series of papers.t The 1,4-addition reactions of the new phenylazo-derivatives with a range of nucleophiles have been investigated and the results have been compared with those obtained previously with analogous com- pounds having the D-erythro configuration.The adducts from the benzylidenated phenylazo-glycenosides in which the acetal and pyranoid rings are cis-fused are found to be relatively unstable in solution and readily revert to the parent phenylazo-giycenoside. From methyl 4,6-O-benzylidene-2,3-dideoxy-2-phenylazo-~-o-th~eo-hex-2-enopyranoside, isolable adducts were obtained in reactions with methylamine, dimethylamine, benzylamine, or hydride ion. Also, stable products were formed in the 1,4-addition reactions of methyl 4,6-0-benzylidene-2,3-dideoxy-3-phenylazo-a-~-threo-hex-~-enopyranosidewith benzylamine, benzenethiol, dimethylamine, or ammonia (followed by acetylation of the ammonia adduct).In continuation of our studies of aryla~o-glycenosides,~-~ Phand particularly our investigation of the value of such compounds as intermediates in syntheses of modified sugars, we have prepared methyl 4,6-0-benzylidene-2,3-dideoxy-2-phenylazo-a-and p-~-threo-hex-2-enopyranosideand methyl 4,6-0-benzylidene-2,3-dideoxy-3-phenylazo-a-D-threo-hex-2-eno-pyranoside from D-galactose by the sequence of reactions described in earlier papers in this serie~.**~~~*~ Nucleophilic addition reactions of these compounds have been compared with those for the corresponding compounds having the D-erythro configuration.In the former compounds the two six-membered rings are cis-fused whereas in the latter the ring fusion is trans. It has been found that arylazo-glycenosides with a cis-fused 0-benzylidene ring undergo addition-elimination reactions more readily than do the analogous compounds with a trans-fused acetal ring. Methyl 4,6-0-benzylidene-a-~-galactopyranoside(1) and its p-anomer (2) were prepared conventionally and were subjected to monobenzoylation. When the glycoside (1) was treated at 0 "C with benzoyl chloride (1 equiv.) in pyridine, reaction was slow and was incomplete even after 24 h. The products were separated by chromatography to yield the 3-benzoate (3) as the major product (30) with a smaller amount of the 2-benzoate (4) (20) and some 2,3-dibenzoate (5) (150/.8 Addition of more benzoyl chloride and a longer reaction time led to an increase in the amount of the 2,3- dibenzoate (5).Several other benzoylating agents and reaction conditions were tested, including 1 -benzoylimidazole in chloroform (a reagent which can show high selectivity) 9*10 which gave compounds (3), (4),and (5) in 15, 12.5, and 30 yield, respectively; the use of a phase-transfer catalyst as described by Lynda et al." compounds (3) :(4) :(5) = 15 :40: 15; and benzoyl cyanide-triethylamine l2 com-pounds (3) :(4) : (5) = 41 :21 : l8.5. When methyl 4,6-O-benzylidene-~-~-galactoside(2) was benzoylated with benzoyl cyanide-triethylamine in acetonitrile the 3-ester (6) was obtained in 69 yield with only 5 of the 2ester (7) and 10 of the 2.3-diester (8).Russian workers l3 7 See reference 2. (I) R'=R3=R4=H, R2= OMe (2) R'=OMe, R2=R3 = R4= H (3) R'=R3=H, Rz=OMe,R4=COPh (4)R' = R4= HI R2=OMe,R3=COPh (5) R' = H , R2= OMe, R3 R4=COPh (6) R'= OMe, R2= R3= H , R4= COPh (7) R'=OMe, R2=R4=HI R3= COPh (8) R'= OMe, R2= H, R3=R4= COPh have reported that benzoylation of the glycoside (2) with benzoyl chloride and 1-benzoylimidazole in chloroform gave the 3-eskr (6) (58) from which the 2ester (7) impurity could be separated by column chromatography over silica. Com-pound (6)can be isomerised to the ester (7) by treatment with sodium hydroxide.There were differences between the physical constants of our compounds and those reported by Veinberg et aZ.13but the 'Hn.m.r. spectra of the monobenzo- ates (3), (4), (6), and (7) were in accord with the assigned structures, as were the 'H n.m.r. spectra of the ulosides derived from the monobenzoates. The monobenzoates (3), (4), and (6)were oxidised with systems based on dimethyl sulphoxide (DMSO) i.e. DMSO-DCC (dicyclohexylcarbodi-imide)-H3P04; DMSO-Ac20 ; DMSO-P4010 but the best yields of the hexosiduloses (9). (lo), and (1 1). respectively, were obtained with DMSO-DCC-H3P04as oxidant," as described by Baker and BUSS.'^ The structures of the ulosides (9), (lo), and (1 1) were deduced 258 J. CHEM. SOC. PERKIN TRANS. I 1983 Ph Ph O (9) R'=H, R2=0Me,X =O (10) R'= Ii,R2=OMe,X=0 (11) R'= OMe, R2= HI X = 0 (17) R'= H, R2=OMe, (12) R1= H , R2=OMe,X =NNHPh X = NNHC,H,(NO2),-2,L* (13) R'=H, R2=OMe,X=NNHC6H4N02-4 (14) R'= H, R2=OMe, X = NNHC6H3(N02),-2,4 (1 5) R'= OMe , R2= ti,X = NN HC6H4N02 -4 (16) R'=OMe, R2= H ,X =NNHC,H,(NO,),-2,4 from their 'H n.m.r.spectra. The signal for the anomeric proton in methyl 3-0-benzoyl-4,6-O-benzylidene-a-~-~yxo-hexopyranosidulose (9) appeared as a singlet at 6 4.91. For compound (1 1) the anomeric proton gives a signal at 6 5.06: expansion of the spectrum showed 1 -H-3-H coupling (Jl,30.7 Hz). Thus, the signal of the (axial) anomeric proton in compound (1 1) resonates at 0.15 p.p.m. lower field than that of the a-D-anomer (9) (cf.reference 2). These results can be rationalised in terms of the anisotropy of the carbonyl gr~up.'~.'~The anomeric proton in compound (10) gave a signal at 6 5.5 with 7 Hz (eq-ax coupling). The arylhydrazones (12)-( 17) were prepared by treatment of the appropriate hexosidulose with the corresponding aryl- hydrazine in dimethylformamide (DMF) and glacial acetic acid.'* The use of DMF had the advantages over other solvents of giving purer products and higher yields. Although the crystalline phenylhydrazone (1 2) can be stored indefinitely, other phenylhydrazones were not obtained and when the uloside (10) or (1 1) was treated with phenylhydrazine the products were, respectively, the phenylazo-alkenes (1 8) and (20).A convenient method for conversion of an arylhydrazone containing an oc-leaving group into an azo-alkene is treatment with a base (methoxide,2 t-butoxide,2 and 1,5-diazabicyclo- 5.4.0undec-5ene have been used successfully). For the preparation of the phenylazo-derivative (19) from the phenyl- hydrazone (12), t-butoxide was used. Monitoring by t.1.c. indicated that the appropriate arylazo- glycenoside is formed when the uloside (9), (lo), or (1 1) is treated with phenylhydrazine or 4-nitrophenylhydrazine in the absence of glacial acetic acid. No isolable products were obtained under these conditions when the ulosides were treated with 2,4-dinitrophenylhydrazine,and attempts to convert the dinitrophenylhydrazones (14), (1 6), and (1 7) into the corresponding azo-alkenes by using prolonged reaction times were unsuccessful.'*19 The phenylazo-glycenosides (1 8), (19), and (20) exhibited ultraviolet absorption in the region 302-305 nm, a shift of 20-25 nm to longer wavelength from the absorption maxi- mum shown by the uloside phenylhydrazone (12) (A,,,,,.278 nm). These values are comparable to others reported pre- viously 'v5 and the value for the phenylhydrazone (1 2) is close to that observed for phenylhydrazone derivatives of similar ketones 20*21 and similar to that reported generally for phenyl- hydrazones of ketone^.^^**^ All the arylhydrazones (12)-( 17) exhibited very strong i.r. absorptions at ca. 1 600 cm-' due to the C=NNHAr group 22*24*z5 and, in addition showed a diagnostic sharp absorption close to 3 300 cm-' due to the N-H group.(18) R' = R3= H, R2= OMe, R4= N=NPh (19) R' = R4= H , R2=OMe, R3= N=NPh (20)R' = OMe, R2=R4= H, R3= N=NPh It is known that arylhydrazones of glycopyranosiduloses can exist as geometric i~omerides.~~~~~~ The arylhydrazones now reported were each obtained in one geometric form. On the basis of the method adopted by Karabatsos and his co- worker~,~'the 4-nitrophenylhydrazone (1 3) was assigned the syn *-structure because the 1-H signal suffered an upfield shift (+0.34 p.p.m.) and 3-H suffered a downfield shift (-0.02 p.p.m.) in 'H,benzene relative to their chemical shifts in CDC13, and hence the ozNC6H4NH group was nearer to 1-H than to 3-H.The structures of the phenylazo-alkenes (1 8)-(20) follow from their method of formation, their elemental analysis, their orange-yellow colour, and their characteristically intense U.V. absorption at 302-305 nm. Mass-spectral measurements and n.m.r. spectra support the structural assignments. In the mass spectra of the phenylazo-glycenosides (18) and (19) a mole-cular-ion peak (M+)appeared at 352. For compound (18) there were abundant peaks at m/z 77,91, and 105 (cf. reference 2) due to C6H5+, C7H7+, and C6H5Nz+ ions, respectively.z8 The first of these is the base peak and presumably is made up of contributions from both phenJl groups present in the molecule. For the azo-alkene (19) the base peak is at m/z 187 and there are strong peaks at m/z 9 1, 121, 149, and 203.The + latter two peaks arise from the hz-ion PhCH=OCH,CHO and h,-ion O=CH-CH=C(NzPh)CH=OCH3 formed by the ' h-fragmentation ' pathway that benzylidene derivatives have been shown 29 to undergo. The 'H n.m.r. spectrum of each compound (1 8), (1 9), and (20) shows the presence of only two phenyl groups, one vinylic proton, but no NH signal (a feature * In this paper the syn-form is iegarded as the isomer in which the arylamino-group is directed towards the ring-carbon atom with lowest number: the other isomer is the anti-form(see reference 26 and also P. M. Collins, Chem. Commrm., 1966, 164). J. CHEM. SOC. PERKIN TRANS. I 1983 259 confirmed by the i.r. spectra). All these observations are consistent with the structures proposed for the phenylazo- glycenosides, each being formed by an eliminative loss of benzoic acid from an intermediate benzoylated phenyl- hydrazone.Addition Reactions to Azo-aZkenes.-Following the findings reported previously on the addition reactions undergone by arylazo-glycenopyranosides, such reactions were attempted with the arylazo-glycenosides (1 8)-(20). The onset of addition could be observed from the colour change (deep-orange to light-yellow) of the reaction mixture. 1,4-Addition across the azo-alkene system leads to formation of an a-substituted phenylhydrazone, reaction (1). Thus, addition to compound (1 8) would lead to A 2-substituted 3-phenylhydrazone deriva- tive of a hexopyranosidulose whereas compounds (19) and (20) should afford 3-substituted 2-phenylhydrazone deriva- tives. To examine the stereochemistry of the adducts, 'H n.m.r.spectral measurements were carried out and recourse was made to the correlation 30 that exists between vicinal coupling constants and stereochemistry in six-membered cyclic systems. This is a method adopted previously to study the adducts from analogous arylazo-glycenosides with the D-eryrhro configuration.2 The generalisation usually made 31 is that Jax,ax > 8 HZ and Ja,,,q and Jeq,eq Jeq,ax > 2 Hz > Jeq,eq.This empiricism is supported by observations made with several ~-glyc~pyranosides.~~-~~Hence, it is usually a simple matter to verify an axial-axial relationship between two vicinal protons but to decide between an axial-equatorial and an equatorial-equatorial relationship is more difficult, particularly as the electronegativity of the substituents attached to the carbon atoms bearing the coupled hydrogen atoms can affect the degree of coupling.However, the method has been used successfully in analyses comparable to those now de- scribed. Initial attempts to form adducts were discouraging and with some nucleophiles the reactions of compounds (18), (19), or (20) were inconclusive :either decomposition occurred or, when evidence of addition was achieved, the adduct was unstable and on attempted isolation it reverted to starting materials.For example, although the colour change and t.1.c. monitoring indicated that the phenylazo-glycenoside (1 8) undergoes reaction with sodium azide in acetone, or sodium methoxide in methanol, or sodium borohydride in methanol t.l.c., solvents 6, c, and e, respectively (solvents defined in Experimental section, Methods) the crude products obtained (which showed absorption for a hydrazone function) under- went decomposition on attempted purification in organic solvents. No adducts were obtained when compound (20) was treated under moderate conditions with azide, methoxide, benzene- thiolate or amines in solvents such as methanol, ethanol, or DMF. Although the azo-alkene (19) undergoes reaction with sodium methoxide in methanol at room temperature, as shown by a colour change in the reaction mixture and t.1.c.monitoring, attempts to isolate the product led to breakdown of the adduct and reformation of compound (19). Clearly, addition-elimination occurs more readily in this series of compounds with the D-rhreo configuration than with those of the D-eryrhro configuration.Z In this connexion it is of (21) R = NHCH,Ph (25) R = NHMe (22) R = SPh (26)R =NMe2 (23)R = NMe2 (27) R = NHCHZPh (24)R = NHCOMe (28) R =tl Compounds (25)-(27) are each 1 epher of unspecified stereo- chemistry at C(3), NOT an epimeric mixture interest to note the results of Baer and his co-workers 36 who have studied extensively the addition reactions of methyl 4,6-0-benzylidene-2,3-dideoxy-3-nitro-~-~-erythro-hex-2-eno-pyranoside and its C(4)-epimer (derived from 3-nitrogalacto- pyranoside).For the D-eryrhro-isomer most of the addition reactions, particularly when carried out under basic condi- tions, proceed with a high degree of selectivity to give mainly products with the substituents at C(2) and C(3) trans-located with the D-gluco configuration. A similar result was reported for the a-D-anomer of the 3-nitroenopyrano~ide.~' However, for the C(4)-epimer with the D-threo configuration, attempted addition of ammonia across the double bond resulted in the loss of the benzylidene group, presumably by a p-elimination process, giving rise to a mixture of products.Under less basic conditions an addition product was obtained but in poor yield.3s The type of ring fusion has an influence on the course of the addition reaction. Other examples of easy addition- elimination reactions have been observed in our lab~ratory.~~ In spite of these discouraging results, some adducts were isolated successfully. It was found that the reaction of benzyl- 'amine with compound (18) was rapid at room temperature and it was possible to isolate the adduct in crystalline form. It showed the anticipated i.r., u.v., and 'H n.m.r. spectral characteristics for a 2-benzylamino-3-phenylhydrazoneof a methyl hexopyranosidulose. The coupling constant (Jz,2 Hz) is consistent with the protons at C(2) and C( 1) being disposed equatorial-equatorial thereby locating the benzylamino-group at C(2) in an axial position.On this basis the compound apparently is methyl 2-benzylamino-4,6-0-benzylidene-2-deoxy-a-~-lyxo-hexopyranosid-3-ulosephenylhydrazone (21). Likewise, crystalline adducts were obtained when the azo-alkene (18) was treated with either benzenethiolate, di- methylamine, or ammonia followed by acetylation. In each case reaction was rapid. Respectively, the products are con- sidered to have the structures (22), (23), and (24), but the configuration at C(2) is not proven unequivocally. Each com- pound showed i.r. and U.V. spectra consistent with the phenyl- hydrazone structure. A signal at 6 8.07 in the 250 MHz 'H n.m.r. spectrum of compound (22) confirmed the presence of an amino-proton: other salient features were doublets at 6 5.08 (assigned to the anomeric proton) and 6 4.99 (assigned to 2-H).The value of JZ,'was 2.2 Hz. As C(1)-H is equatorial in this compound in its most likely conformation, this coup- ling indicates that C(2)-H is also equatorially disposed which indicates a D-Z~XO configuration for the compound. The configurations shown in the formulae for compounds (23) and (24) are based on analogy. For the 2-dimethylamino-com- pound (23) this could not be tested because the adduct under- went elimination when its solution in CDC13 was being used for 'H n.m.r. spectra determinations and so interpretable spectra could not be obtained. In the 250 MHz 'H n.m.r. spec- tnun of compound (24) a signal at 6 9.08 was assigned to the NH proton (exchangeable with D20)of the phenylhydrazone.Signals at 6 4.89 and 5.03 were assigned to 1-H and 2-H, respectively. There was a large coupling (10 Hz) between 2-H and the N-H proton of the geminal acetamido-group. The deshielding influence of the acetamido-group at C(2) resulted in the proton at C(2) being at low field relative to that at C(1). From the phenylazo-glycenoside (19) crystalline adducts were obtained with methylamine, dimethylamine, benzyl- amine, or sodium borohydride. The elemental analysis and spectral characteristics of each adduct were consistent with the products being 3-substituted derivatives of methyl 4,6-0- benzylidene-3-deoxy-a-~-lyxo-(orxylo-) hexopyranosidulose phenylhydrazone, i.e.compounds (25)-(28). Analysis of the 'H n.m.r. spectrum of the methylamine adduct (25) revealed a signal at 6 3.6 (d, 3-H) with J3,43.5 Hz. The proton at C(4) gave a signal at 6 4.26 (dd) with J4,3 2 Hz. If 4-H is3.5 and J4,5 equatorial this would point to 3-H being axial and to com- pound (25) having the D-lyxo configuration. The spectra of compounds (26) and (27) were not interpretable owing to solutions of the substances in CDC13 undergoing decomposi- tion during the spectral measurements. When compound (1 9) was reduced with sodium borohydride in methanol it afforded a single product which analytical and spectral evidence indicated was methyl 4,6-0-benzylidene-3- deoxy-a-D-threo-hexopyranosidulosephenylhydrazone (28).In an attempt to ascertain the stereochemistry of the hydride addition, the reaction was repeated under identical conditions with sodium borodeuteride in methan2Hol. With methyl 4,6-0-benzylidene-2,3-dideoxy-2-phenylazo-a-D-erythro-hex-2-enopyranoside a change from borohydride to borodeuteride had led to products from which useful information could be deduced.2 Each reagent led to a 3-deoxyglycopyranosidulose phenylhydrazone but the 3-deuterio-product had shown a simplification of the C(3)-methylene signals observed in the 'H n.m.r. spectrum when compared with the non-deuteriated product, This enabled the configuration to be deduced as D-rib0 and thereby led to information about the stereochemistry of the reduction.Unfortunately, the second-order 'H n.m.r. spectrum of the deuteride reduction of compound (19) was less informative, particularly as regards the multiplicity of the C(3)-methylene signals, and it seems possible that hydride addition may have taken place from both directions. A comparison of the 2- and 3-phenylazo-derivatives of methy1 4,6-0-benzy1idene-2,3-dideoxy-~-hex-2-enopyrano-sides having the D-erythro and D-threo configurations reveals the greater difficulty of working with the D-threo compounds. Whereas relatively stable 1,dadducts are formed by the phenylazo-derivatives of D-erythro configuration in which the acetal and pyranoid rings are trans-fused, the adducts from the benzylidenated D-threo-phenylazo-glycenosides with a cis-fused ring system are relatively unstable and difficult to examine in solution.Experimenta1 Methods.-1.r. spectra were measured with a Perkin-Elmer Infracord model 137: solid samples were dispersed in KBr and gums were smeared on KBr discs; U.V. spectra were obtained for 96 ethanolic solutions with a Perkin-Elmer spectrophotometer model 402; optical rotations were measured on solutions in chloroform (unless otherwise stated) with a Bellingham and Stanley polarimeter ; mass spectra were measured with an A.E.I. MS 902 instrument operated with an ionising potential of 70 eV and a probe inlet temperature of 150°C; n.m.r. spectra were determined with either a JEOL M 100 instrument, a Varian H.A. 220 spectrometer, a Bruker J.CHEM. SOC. PERKIN TRANS. I 1983 W.M. 250 instrument, or a JEOL FX 200 F.T. spectrometer: 'H spectra were measured at 100 MHz unless otherwise stated and measurements were carried out on solutions in CDCl, (with internal Me4Si) unless indicated otherwise: the J values cited in this paper are line spacings which were deduced by first-order analysis of the n.m.r. spectra. T.1.c. (thin-layer chromatography) was carried out on Kieselgel GF254 (Stahl) with one of the following solvent systems (v/v): (a) benzene; (b) benzene-ethyl acetate (5 : 1); (c) benzene-ethyl acetate (8 : 1); (d) benzene-methanol (20 : 1); (e) chloroform-diethyl ether (4: 1); (f) methylene dichloride; (g) methylene di- chloride-ethyl acetate (4 : 1); (h) methylene dichloride-ethyl acetate (9 : 1): compounds were located with p-anisaidehyde- sulphuric acid or with a U.V.lamp: purity of samples was tested by t.1.c. analysis in two different solvent systems; p.1.c. (preparative layer chromatography) was effected on glass plates (100 x 20 cm) coated to a depth of 0.1 mm with Kieselgel GF254 (Stahl): the compound in a volatile solvent was applied by means of a Buckard t.1.c. applicator (type S.A 100); the plate was developed by vertical ascent of the solvent and components were located with a U.V. lamp. Fractions were retrieved by washing them from the silica gel with either acetone or ethyl acetate; column chromatography was carried out on Kieselgel columns which had been wet-packed. Light petroleum refers to that fraction boiling in the range 40- 60"C.Preparation of Methyl Glycopyranosidu1oses.-Methyl 2-0-benzoyl-and 3-0-benzoyl4,6-0-benzylidene-a-~-galacto-pyranoside (4) and (3). (a) A solution of benzoyl chloride (14 ml) in pyridine (25 ml) was added during 1 h to a cooled (0-5 "C), stirred solution of methyl 4,6-O-benzylidene-a-~- galactopyranoside (1) 40 (28 g) in pyridine (60 ml). After a further 4 h the reaction mixture was warmed to room temp- erature and was so maintained overnight. Ice-water (750 ml) was then added to the vigorously stirred mixture and the solid which ssparated was collected by filtration and was washed with cold water (2 x 150 ml). A solution of the solid in chloroform (250 ml) was washed sequentially with 2~ hydro- chloric acid (100 ml) and with water (3 x 250 ml) and was dried (MgS04).Evaporation of the solvent gave a syrupy residue of mixed benzoates which was separated on a column of silica gel (solvent h). The fractions were monitored by t.1.c. Methyl 2,3-di-0-benzoyl-4,6-O-benzylidene-a-~-galacto-pyranoside (5) (7.5 g, 15) was eluted first. It was obtained as needles, m.p. 201-202°C; aD +231" (c, 0.18); V,,~, 1 710 cm-' (CO) (lit.," m.p. 201-203 "C; +231.3"). Methyl 2-O-benzoyl-4,6-O-benzylidene-oc-~-galactopyrano-side (4) (7.6 g, 20) was obtained as needles from the next set of fractions. It had m.p. 189-190 "C; aID+ 164.5" (c, 0.15); vmax.3 600 (OH) and 1700 cm-' (CO); 6" 8.24-7.26 (total 10 H, complex m, 2 x Ph), 5.6 (1 H, s, PhCN), 5.4 (1 H, dd, J2.3 9, J2,1 4 Hz, 2-H), 5.14 (1 H, d, J1.2 4 Hz, 1-H), 4.4U.O (total 4 H, complex m, 3-, 4-, 6-, and 6'-H), 3.78 (1 H, complex m, 5-H), 3.44 (3 H, s, OMe), and 2.48 (1 H, d, OH) (Found: C, 65.1 ;H, 5.7.Calc. for CZ1H2207: C, 65.25; H, 5.75) (lit.,8 m.p. 202-204 "C; + 145.8 f1.7"). Finally, methyl 3-0-benzoyl-4,6-0-benzylidene-a-D-galacto-pyranoside (3) (1 1.5 g, 30) was obtained. After recrystailis- ation from ethanol it had m.p. 139 "c; ciD $235.7" (c, 1.12); vmX. 3 500 (OH) and 1 725 cm-I (CO); 6, 8.24-7.28 (total 10 H, complex m, 2 x Ph), 5.54 (1 H, s, PhCH), 5.4 (1 H, dd, J3.2 10,J3.4 4 Hz, 3-H), 5.0 (1 H, d, J1,2 4 Hz, I-H), 4.58-3.98 (total 4H, complex m, 2-, 4-, 6-, and 6'-H), 3.78 (1 H, complex m, 5-H), 3.46 (3 H, s, OMe), and 2.2 (1 H, d, OH) (Found: C, 65.2; H, 5.9.Calc. for C21H2207: C, 65.25; H, 5.75) (lit.,8 m.p. 137-139 "C; aIDl9+235.7 2").(b) Triethylamine (0.5 ml) was added to a stirred mixture J. CHEM. SOC. PERKIN TRANS. I 1983 of methyl 4,6-O-benzylidene-a-~-galactopyranoside(1) (10 g) and benzoyl cyanide (4.7 g) in acetonitrile (50 ml). The reaction was shown to be complete in 15 min (t.l.c., solvent h). The light-yellow solution was diluted with methanol (100 ml) and the mixture was stirred for a further 30 min and was then concentrated to afford a syrup. Methanol (2 x 75 ml) was added to and evaporated over the syrup which was then separated chromatographically on a silica-gel column (solvent h) to afford the 2-benzoate (4) (2.8 g, 21), the 3-benzoate (3) (5.5 g, 40), and the 2,3-dibenzoate (5) (3.2 g, 18.5), all three identical with authentic samples previously prepared.Methyl 2-0-benzoyl- and 3-0-benzoyl-4,6-0-benzylidene-P-D-galactopyranoside (7) and (6). Methyl 4,6-O-benzylidene- B-D-galactopyranoside (2) 41 (10 g) and benzoyl cyanide (4.7 g) were stirred in acetonitrile (50 ml) and triethylamine (0.5 ml) was added. After 10 min (complete reaction: t.l.c., solvent g) the solution was diluted with methanol (75 ml) and was stirred for a further 30 min. The solution was then concentrated under reduced pressure and methanol (2 x 100 ml) was added to and evaporated over the residue. Fractional crystallisation of the residue from methanol yielded the 3-benzoate (6) (9.5 g, 69), m.p.165 "C; aID +94.4" (c, 1.1); vmx. 3 590 (OH) and 1 695 cm-I (CO); 8H8.28-7.3 (total 10H, complex m, 2 x Ph), 5.54 (1 H, S, PhCN), 5.2 (I H, dd, J3.2 9, J3,; 4 Hz, 3-H), 4.6-4.0 (total 6 H, complex m, I-, 2-, 4-, 5-, 6-, and 6'-H), 3.6 (3 H, s, OMe), and 2.56 (1 H, d, OH): the 100 MHz n.m.r. spectrum of the substance in 'H6DMS0 was essentially the same as that reported by Veinberg et al.13 (Found: C, 65.3; H, 5.7. Calc. for C21H2207: C, 65.25; H, 5.75) {Iit.,l3 m.p. 163-164 "C(from propan-1-01); aIDz3 +137"(c, 1 in pyridine); vOH 3 560 cm-l}. When a solution of the 3-benzoate (6) (5 g) in acetone (250 ml) was treated with 0.05~sodium hydroxide (250 ml) a precipitate was formed. The mixture was kept for 15 min at ambient temperature and was then diluted with ice-water (200 ml).The precipitate was collected by filtration, washed (water, 4 x 100 ml) and dried over KOH in uacuo. Recrystallisa- tion from ethanol gave methyl 2-0-benzoyl-4,6-0-benzylidene-P-D-galactopyranoside (7) (2.1 g, 42), m.p. 232-233 and 236 "C (from propan-2-01); aID+28.7 (c, 0.4) and +24" (c, 0.3 in C5H5N); vmax.3 540 (OH) and I 705 cm-' (CO); SH (ZH6DMSO)8.18-7.34 (total 10 H, complex m, 2 x Ph), 5.7 (I H, S, PhCH), 5.18 (I H, td, J2.1 8, J2.3 8 Hz, 2-H), 4.6 (1 H, d, J1,28 Hz, 1-H), 4.36-3.44 (total 5 H, complex m, 3-, 4-, 5-, 6-, and 6'-H), and 3.4 (3 H, s, OMe) (Found: C, 65.2; H, 5.75. Calc. for CZ1HZ20,: C, 65.25; H, 5.75) {lit.,13 m.p.250- 261 4-H), 4.38 (1 H, dd, J6, 1.8 Hz, 6-H), 4.29br (1 H,12.5, J6,5 5-H), 4.18 (I H, dd, J6p.6 12.5, J60.5 1.5 Hz, 6'-H), and 3.54 (3 H, s, OMe) (Found: C, 65.5; H, 5.3. C2#7 requires C, 65.6; H, 5.25). Methyl 3-O-benzoyl-4,6-O-benzylidene-~-~-lyxo-hexopyran-osidulose (11). The 3-benzoate (6) (8 g) was oxidised in a similar way to that of the a-anomer to afford the 0-D-glyco- pyranosidulose (1 1) (4.5 g, 56), m.p. 186 "C (from diethyl ether-light petroleum); aID +93.2" (c, 0.12); vmX. 1 760 (CO) and 1 735 cm-' (CO of COPh); SH(250 MHz) 8.10-8.14 (2 H, m, aromatic protons ortho in benzoate residue), 7.35-7.62 (total 8 H, m, ArH), 5.80 (1 H, dd, J3,43.7, J3.1 0.7 Hz, 3-H), 5.60 (1 H, S, PhCN), 5.06 (1 H, d, J1.3 0.7 Hz, I-H), 4.81 (1 H, dd, J4,3 3.7, J4.5 1.5 HZ, 4-H), 4.43 (I H, dd, J6.6' 12.5, J6.5 1.8 Hz, 6-H), 4.20 (1 H, dd, J6e,6 12.5, J6n,5 1.8 Hz, 6'-H), 4.07br (1 H, 5-H), and 3.62 (3 H, s, OMe) (Found: C, 65.3; H, 5.3.CllHZ0O7 requires C, 65.6; H, 5.25). Methyl 2-O-benzoyl-4,6-O-benzylidene-a-~-xylo-hexo-pyranosid-3-ulose (10). Methyl 2-0-benzoyl-4,6-0-benzyl-idene-a-D-galactopyranoside(4) (1 5 g) was oxidised by the same method as used for the other isomers and yielded the title compound (1 1.2 g, 75) as a syrup, aID +231" (c, 0.37); vmx. 1 760 (CO) and 1 725 cm-' (CO of COPh); 8, 8.3-7.2 (total 10 H, complex m, 2 x Ph), 6.3 (1 H, d, Jz,l7 Hz, 2-H), 5.7 (1 H, S, PhCH), 5.5 (1 H, d, J1.2 7 Hz, I-H), 4.6 (1 H, d, J4,52 Hz, 4-H), 4.5-4.0 (total 3 H, complex m, 5-, 6-, and 6'-H), and 3.6 (3 H, s, OMe).Preparation of Methyl Glycopyranosidulose Arylhydrazones and Methyl Arylazo-hexenosides.-Methyl3-0-benzoyl-4,6-0-benzylidene-a-D-lyxo-hexopyranosidulosephenylhydrazone(I 2). Methyl 3-O-benzoyl-4,6-O-benzylidene-a-~-lyxo-hexopyran-osidulose (9) (4 g) was dissolved in DMF (20 ml) and a solution of phenylhydrazine (1.1 ml) in glacial acetic acid (0.2 ml) was added. The mixture was stored in the dark for 10 h at room temperature and then ice-water (500 ml) was added to the vigorously stirred mixture. A solid separated and was collected by filtration and dried (Pz05, in vacuo). Re- crystallisation from absolute ethanol afforded the title com-pound (4.2 g, 86"/,), m.p.177 "C; aID +224" (c, 0.33); vmX. 3 300, 1 725, 1 600,and 1 500 cm-' ;h,, 278 nm (E 20 856); SH 8.2-6.7 (total 16 H, complex m, 3 x Ph and NH), 6.04 (1 H, d, Jj.4 4.5 Hz, 3-H), 5.68 (I H, S, PhCH), 5.58 (1 H, S, I-H), 4.56 (1 H, dd, J4.3 4.5, J4.5 1.5 Hz, 4H), 4.32 (1 H, dd, J6.6' 12.5, J6.5 1.0HZ, 6-H), 4.12 (I H, dd, Jat.6 12.5, J6#,51.5 HZ, 6'-H), 3.98 (1 H, complex m, 5-H), and 3.5 (3 H, s, OMe) 251 "C (from n-propanol); aD23 +43.5" (c, 1 in C5H5N); (Found: C, 68.1 ;H, 5.5; N, 5.8. C27H26N206 requires C, 68.3; vOH 3 530 cm-I}. H, 5.5; N, 5.9). Methyl 3-0-benzoyl-4,6-0-benzylidene-a-~-lyxo-hexo-Methyl 3-O-benzoyl-4,6-O-benzylidene-a-~-lyxo-hexopyran-pyranosidulose (9). Molten dicyclohexylcarbodi-imide(1.7 g) and anhydrous phosphoric acid (0.6 g) were added sequentially to a stirred solution of methyl 3-O-benzoyl-4,6-0-benzylidene-a-D-galactopyranoside (3) (10 g) in DMSO (100 ml).After storage for 24 h at ambient temperature, the mixture was treated with oxalic acid dihydrate (10 g). N,N'-Dicyclohexyl- urea oxalate was removed by filtration and was carefully washed sequentially with dilute aqueous sodium hydrogen carbonate and with saturated aqueous sodium chloride. The organic layer of the combined filtrate and washings was dried (MgS04) and concentrated under reduced pressure. The residue was dissolved in ethyl acetate and tHd. filtered solution was reconcentrated. The residue was crystallised from hot, absolute ethanol to give the title compound (8.3 g, 83.5), m.p.158 "C; aID +228" (c, 0.2); v,,,,. 1 765 (CO) and 1 725 cm-' (CO of COPh); (250 MHz) 8.10-8.20 (2 H, complex m, aromatic protons ortho in benzoate residue), 7.33-7.61 (total 8 H, m, ArH), 6.10 (I H, d, J3.4 4.0 Hz, 3-H), 5.61 (1 H, S, PhCH), 4.91 (I H, S, I-H), 4.82 (1 H, dd, J4,3 3.7, J4.5 0.7 Hz, osidulose 4-nitrophenylhydruzone (1 3). A solution of compound (9) (1 g) in absolute ethanol (10 ml) was added slowly to a stirred solution of 4-nitrophenylhydrazine (0.4 g) in ethanol (5 ml). Glacial acetic acid (0.3 ml) was then added and the mixture was warmed and kept at 45 "C for 30 min. The solution was then cooled slowly and kept at 0 "C for 3 h. The oil which separated was crystallised by th3 addition of ice- water (40ml) with stirring of the mixture.Filtration afforded yellow crystals of the title compound (I. 1 g, 813)which, after recrystallisation from ethanol-water (4 : l), had m.p. 121 "C; aD +315" (c, 0.24); vmX. 3 350 (NH), I 730 (COPh), 1 600, and 1495 cm-'; hmx. 378 nm (E 26 200); tiH (?H6benzene) 8.25-6.2 total 15 H, complex m, 2 x Ph, CsH.,N02, and NH (exchangeable on D20 shake), 5.98 (1 H, d, J3,r3.5 Hz, 3-H), 5.8 (1 H, s, PhCH), 5.3 (1 H, s, I-H), 4.0-3.6 (total 2 H, complex m, 4- and 6-H), 3.36 (I H, dd, J6',6 12, J6.,5 1.0 Hz, 6'-H), 3.14 (1 H, complex m, 5-H), and 3.0 (3 H, s, OMe) (Found: C, 62.5; H, 4.9; N, 8.0. CZ7HZ5N3O8requires C, 62.4; H, 4.85; N, 8.1). J. CHEM. SOC. PERKIN TRANS. I 1983 Likewise, methyl 3-0-benzoyl-4,6-0-benzylidene-a-~-lyxo-hexopyranosidulose 2,4-dinitrophenylhydrazone (14) was pre- pated from compound (9) (1 g) in DMF (5 ml) and 2,4-di- nitrophenylhydrazine (0.52 g) in glacial acetic acid (0.2 ml).After storage in darkness for 8 h the product was isolated as a yellow powder (1.4 g, 93) which was washed with water and dried (P205, in uacuo). The product had m.p. 109 "C; KID+253" (c, 0.2); vmX. 3 300 (NH), 1 710 (CO of COPh), 1615, and 1510 cm-'; A,,mx. 350 nm (E 47 100) (Found: N, 10.6. C27H24N4010 requires N, 9.9). Methyl 3-0-benzoyl-4,6-0-benzylidene-~-~-lyxo-hexopyran-osidulose 4-nitrophenylhydrazone (1 5). Compound (1 1) (1 g) was treated with 4-nitrophenylhydrazine (0.4 g), DMF (8 ml), and glacial acetic acid (0.5 ml) for 15 h.Yellow crystals of the 4nitrophenylhydrazone were obtained (0.92 g, 68), m.p. 136 "C (from 96 ethanol); vnux. 3 295 (NH), 1 700 (CO of COPh), 1600, and 1510 cm-'; Amx. 378 nm; tiH 8.38 (1 H, s, exchangeable with D20, NH), 8.28-6.62 (total 14 H, complex m, 2 x Ph and C6H4N02), 6.06 (1 H, d, J3,44 Hz, 3-H), 5.72 (1 H, S, PhCH), 5.64 (1 H, S, 1-H), 4.6 (1 H, dd, J4,3 1.5 Hz, 4-H), 4.44-4.0 (total 2 H, complex m, 6- 4, J4,5 and 6'-H), 3.96 (1 H, complex m, 5-H), and 3.44 (3 H, s, OMe) (Found: N, 7.9. C27H25N308 requires N, 8.1). The analogous 2,4-dinitrophenylhydrazone(1 6) (0.97 g, 66) was prepared from compound (1 1) (1 g), 2,4-dinitrophenyl- hydrazine (0.52 g), DMF (1 ml), and glacial acetic acid (0.5 ml), and was obtained as orange crystals, m.p.128 "C (decomp.); vmx. 3 300 (NH), 1705 (CO of COPh), 1 620, 1 580, and 1 520 cm-'; A,,,. 350 nm (E 22 500); tjH(2H6benzene) 9.74- 6.66 (total 14 H, complex m, 2 x Ph, C6H3(N02)2, and NH), 5.34 (1 H, S, PhCH), 5.1 (1 H, d, J3.4 4 Hz, 3-H), 5.06 (1 H, S, 1-H), 4.1-3.2 (total 4 H, complex m, 4-, 5-, 6-, and 6'-H), and 3.26 (3 H, s, OMe) (Found: N, 9.8. C27H24N4010 requires N, 9.9). Methyl 4,6-0-benzylidene-2,3-dideoxy-2-phenylazo-a-~-threo-hex-2-enopyranoside (19). Sodium hydride (0.5 g) in 2-methylpropan-2-01 (20 ml) was added to a solution of the phenylhydrazone (12) (10 g) in DMF (75 ml) at room temp- erature. The mixture was set aside for 4 h in a dark cupboard and was then poured into stirred ice-water (800 ml). The solid which separated was collected and dried (P205,in uacuo).On recrystallisation from ethanol the phenylazo-compound (1 9) (7 g, 94) was obtained, m.p. 190°C; aID -617" (c, 0.23); lux.305nm; tiH 8.16-7.26 (total 10 H, complex m, 2 x Ph), 7.16 (1 H, d, J3,45 Hz, 3-H), 5.82 and 5.8 (total 2 H, over-lapping s, PhCH and 1-H), 4.72 (1 H, dd, J3,4 2 Hz, 4-H), 5, J4,5 4.6-4.06 (total 3 H, complex m, 5-, 6-, and 6'-H), and 3.6 (3 H, s, OMe) (Found: C, 67.85; H, 5.7; N, 8.0. CzoHzoN204 requires C, 68.2; H, 5.7; N, 7.95). Methyl 4,6-0-benzylidene-2,3-dideoxy-2-phenylazo-~-~-threo-hex-2-enopyranoside(20). A solution of methyl 3-0- benzoyl-4,6-~-benzylidene-~-~-lyxo-hexopyranosidulose(1 1) (2 g) in DMF (10 ml), when treated with phenylhydrazine (0.5 ml) and glacial acetic acid (0.5 ml) for 8 h, afforded the title compound (1.34 g, 90), m.p.212 "C (from aqueous ethanol); Amx. 305 nm; 6H7.9-7.26 (total 10 H, complex m, 2 x Ph), 6.94 (1 H, d, J3,45.5 Hz, 3-H), 5.68 (total 2 H, PhCH and 1-H), 5.64 (1 H, dd, J4,35.5, J4,52 Hz, 4-H), 4.524.16 (total 2 H, complex m, 6- and 6'-H), 4.08 (1 H, complex m, 5-H), and 3.6 (3 H, s, OMe) (Found: C, 68.9; H, 6.2; N, 7.9. C20H20N204 requires C, 68.2; H, 5.7; N, 7.95). 1,CAddition Reactions of the Phenylazo-a-D-glycenosides (18) and (19).-(i) Additions to methyl 4,6-0- benzylidene-2,3- dideoxy-3-phenylazo-a-~-threo-hex-2-eno~yranoside(18). (a) Benzylumine. Benzylamine (0.5 ml) was added to a solution of the 3-phenylazo-alkene (18) (0.15 g) in DMF (3 ml).T.1.c. monitoring (solvent c) showed that reaction was com-Methyl 2-0-benzoyl-4,6-0-benzylidene-a-~-xylo-hexopyran-plete in 2 h and then the mixture was poured into stirred ice- osid-3-ulose 2,4-dinitrophenylhydrazone(1 7). This compound water (10 ml) to yield a pale-yellow solid (0.17 g, 87) which was prepared from methyl 2-0-benzoyl-4,6-0-benzylidene-was collected by filtration, washed with water (3 x 20 ml), a-~-xylo-hexopyranosid-3-ulose(10) (1 g), 2,4-dinitrophenyl-hydrazine (0.52 g), DMF (12 ml), and glacial acetic acid (0.5 ml) according to the procedure described for the preparation of compound (14). Orange-yellow crystals (1.34 g, 91) of compound (1 7) were obtained, after recrystallisation from ethanol-water (2 : l), with m.p.142 "C; vmx. 3 300 (NH), 1 720 (CO of COPh), 1 615, 1 580, and 1 510 cm-'; h,, 350 nm; tiH (220 MHz) 9.5-7.6 (total 14 H, complex m, 2 x Ph, C6H3(N02)2,and NH), 6.25 (1 H, d, J2,' 5.5 Hz, 2-H), 5.81 (1 H, S, PhCH), 5.3 (1 H, d, Jl,2 5.5 Hz, 1-H), 5.22 (lH, d, J4.5 1.25 Hz, 4-H), 4.554.3 (total 2 H, 2 X dd, J6.g 13, J6.s 1.25 Hz, 6- and 6-H), 4.07 (I H, complex m, 5-H), and 3.5 (3 H, s, OMe) (Found: N, 9.9. C27H24N4010 requires N, 9.9). and dried (PZOS, in uacuo). The methyl 2- benzylamino-4,6-0- benzylidene-2-deoxy-u-~-lyxo-hexopyranosid-3-ulosephenyl-hydrazone (21) so obtained had m.p. 128-130 "C; kmx.284 nm; vmx. 3 200 and 1 600 cm-'; tiH 8.56 (1 H, s, NNH), 7.88-6.9 (total 15 H, complex m, 3 x Ph), 5.78 (1 H, s, PhCH), 5.14 (1 H, d, J2.1 2 Hz, 1-H), 5.08 (1 H, d, J4.5 2 Hz, 4-H), 4.W.12 (total 2 H, 2 x dd, J6,52, J6,6e 13 Hz, 6- and 6'-H), 3.98-3.8 (total 2 H, complex m, 2- and 5-H), 3.48 (3 H, s, OMe), 3.26 (2 H, complex m, CH2Ph), and 2.9br (1 H, s, NHCH2Ph) (Found: C, 70.95; H, 6.6; N, 8.8.C27H29N304 requires C, 70.6; H, 6.3; N, 9.1). (b) Benzenethiof. Benzenethiol (0.5 ml) and sodium hydride (ca. 20 mg) were added sequentially to a solution of the phenylazo-glycenoside (18) (0.2 g) in acetone (5 ml). When the Methyl 4,6-0-benzylidene-2,3-dideoxy-3-phenylazo-a-~-solution was warmed to 4-5 threo-hex-2-enopyranoside(18). The uloside (10) (5 g) was dissolved in a mixture of DMF (50 ml) and glacial acetic acid (1 ml). Phenylhydrazine (1.3 ml) was added and the mixture was stored for 20 h in the dark at room temperature and was then poured into stirred ice-water (400ml) and the yellow solid which separated was collected by filtration, washed with water (3 x 50 ml), and dried (P2O5, in uacuo).The title phenylazo-compound (3.9 g, 85), when recrystallised from 96 ethanol, had m.p. 205 "C; aID-356" (c, 0.2); A,, 302 nm (E 20 240); 6,, 8.27-7.44 (total 10 H, complex m, 2 x Ph), 7.12 (1 H, d, J2.1 4 Hz, 2-H), 5.86 (1 H, S, PhCH), 5.68 (1 H, d, J1.2 4 Hz, 1-H), 5.24 (1 H, d, J4.5 2 Hz, 4-H), 4.64 (1 H, dd, J6.5 1.5, J6.w 13.5 Hz, 6-H), 4.4 (1 H, dd, J6.g 13.5 Hz, 6'-H), 4.02 (1 H, complex m, 5-H), and 3.66 (3 H, s, OMe) (Found: C, 68.3;H, 5.5 ;N, 8.05. C20HzoN204requires C, 68.2 ;H, 5.7; N, 7.95). "C for 10 min its orange colour faded to a light-yellow;the reaction was monitored by t.1.c.(solvent b) and was shown to be complete. The solvent was evaporated under diminished pressure to give a mixture (0.23 g) of two products. The major component, methyl 4,6-0-benzylidene-2-deoxy-2-phenylthio-a-D-lyxo-hexopyran-osid-3-dose phenylhydrazone (22) (0.18 g, 7373, was separated by crystallisation from diethyl ether. When recrystallised from propan-2-01-water (5 : 1) it had m.p. 146 "C; vmax.3 350 and 1 590 cm-'; A,,, 290 nm; 6H (250 MHz) 8.07 (1 H, s, NH), 6.83-7.67 (total 15 H, m, 3 x Ph), 5.73 (1 H, s, PhCH), 5.08 (1 H, d, J1,Z 2.2 Hz, 1-H), 4.99 (1 H, d, JZ.1 2.2 Hz, 2-H), 4.43 (1 H, dd,Jh,6' 12.9 J6.5 1.1 HZ, 6-H), 4.27 I H, dd,J6,6* 12.9, J6',5 2.6 Hz, 4-H), 3.85br 2.0 Hz (av.), 6'-H, 4.08 (1 H, d, J4,5 (1 H, 5-H), and 3.35 (3 H, s, OMe) (N.B.there is a possibility that the assignments to 2- and 4-H could be interchanged). (c) Dimethylamine. Solutions of compound (1 8) (0.3 g) in J. CHEM. SOC. PERKIN TRANS. I 1983 ethanol (5 ml) and dimethylamine in ethanol (2 ml of a 33 w/v solution) were mixed. The orange colour of the mixture faded rapidly when it was warmed to 50 "C (t.l.c., solvent c). The mixture was concentrated to dryness and the solid residue (0.33 g, quantitative) was crystallised from ethanol-water (5 : 1). The product, methyl 4,6-0- benzylidene-2-deoxy-2- dimethylamino-a-~-lyxo-hexopyranosid-3-ulose phenylhydr-azone (23), had m.p.193 "C;vmx. 3 250 and 1 ;590 cm-' ;A,,,,,. 285 nm (Found: C, 66.45; H, 6.9; N, 10.5. C22H27N304 requires C, 66.5; H, 6.85; N, 10.6). (d) Ammonia. Aqueous ammonia (S.G. 0.88; I ml) was added to a solution of the phenylazo-alkene (18) (0.2 g) in ethanol (4 ml). During the time the solution was being stirred over 6 h at room temperature its colour changed from orange to light-yellow and t.1.c. (solvent d) showed that the reaction was essentially complete. The solvent was evaporated off and the syrupy residue was dissolved in methanol (5 ml) and acetylated with acetic anhydride (0.7 ml). Methyl 2-acetamido- 4,6-0- benzylidene-Zdeoxy- a-~-lyxo-hexopyranosid-3-ulose phenylhydrazone (24) (0.21 g, 94) was obtained in crystalline form on the addition of ice-water (5 ml).The crystals were collected, washed thoroughly with cold water (2 x 20 ml), and dried (PzOs, in uacuo), m.p. 162 "C; vwx. 3 270, 1 700, and 1600 cm-'; A,,,. 284 nm; 6, (250 MHz) 9.08 (1 H, s, exchangeable on D20shake, NNH), 6.83-7.59 (total 10 H, m, 2 x Ph), 6.54 (1 H, d, JNHAc,Z 10 Hz, NHAc), 5.66 (1 H, s, PhCH), 5.03 (1 H, d,J2,NHAc IO Hz, 2-H), 4.89 (I H, S, l-H), 4.60 (1 H, S, 4-H), 4.37 (1 H, dd, J6,6* 12.8, JS.5 1.5 HZ, 6-H)* 4.23 I H, dd, J6,i12.8, J6,51.6 Hz (av.), 6'-HI, 3.96br (1 H, 5-H), 3.41 (3 H, s, OMe), and 1.92 (3 H, s, NHAc) (Found: N, 9.75. Cz2HzsN30srequires N, 10.2).(ii) Additions to methyl 4,6-0- benzylidene-2,3-dideoxy-2-phenylazo-u-~-threo-hex-2-enopyrarzoside(1 9).(a) Methyl-amine. A solution of the phenylazo-alkene (19) (0.4 g) in ethanol (10 ml) was treated with a solution of methylamine in ethanol (3 ml of a 33 w/v solution) at reflux temperature for 1 h during which time the deep-yellow colour of the mixture faded. The product was isolated in the customary manner and methyl 4,6-0- benzylidene-3-deoxy-3-methylamino-a-~-lyxo-(or xylo-) hexopyranosidulose phenylhydrazone (25) (0.3 g, 69) was obtained with m.p., 98-99 "C; vmx. 3 300 and 1 590 cm-';A?,. 281 nm; 8H('H6benzene) 8.68 (1 H, s, exchangeable with D20,NNH), 7.9-6.98 (total 10 H, m, 2 x Ph), 5.76 (1 H, S, PhCH), 5.64 (1 H, S, 1-H), 4.52 (I H, dd, J6,6' 13.5, J6.s 1.5 Hz,6-H), 4.3 (I H, dd, J6',6 13.5, J6#,5 2 Hz, 6'-H), 4.26 (1 H, dd, J4,3 2 Hz, 4-H), 4.02 (1 H, complex m, 5-H), 3.5, J4,5 3.64 (3 H, s, OMe), 3.6 (1 H, d, J3,43.5 Hz, 3-H), 2.68 (3 H, s, NMe), and 2.14 (1 H, s, NHMe) (Found: N, 10.3.C21H25-NjOq requires N, 10.9). (b) Dimethylamine. A solution of compound (19) (0.5 g) in DMF (10 ml) was treated with a solution of dimethylamine in ethanol (2 ml of a 33 w/v solution) at 45 "C. T.1.c. (solvent c) showed that the reaction was complete in 30 min. The dimethylamino-adduct, methyl 4,6-0-benzylidene-3-deoxy-3-dimethylamino-a-D-lyxo-(or xylo-) hexopyranosidulose phenyl- hydrazone (26), was isolated as a pale-yellow solid (0.24 g, 7573, m.p. 116-118 "C (from ethanol-water, 6: 1); v,,, 3 310 and 1605 cm-'; Amx. 282 nm; 6H (2H6benZene) 9.9 (1 H, s, NNH), 7.64-6.88 (total 10 H, m, 2 x Ph), 5.3 and 5.26 (total 2 H, s and 2 overlapping s, PhCH and 1-H), 4.06 (1 H, dd, J6,6' 13, J6.5 2 Hz, 6-H), 3.8 (I H, dd, J4.5 1.5, J4.3 1 Hz, 4-H), 3.68 (I H, m, 5-H), 3.54 (1 H, d, J3,41 Hz, 3-H), 3.24 (1 H, dd, J6,,6' 13, J6;,51.5Hz, 6'-H), 3.1 (3 H, s, OMe), and 2.0 (6 H, s, NMe,) (Found: C, 66.7; H, 7.0.C22H27N304 requires C, 66.5; H, 6.85)). (c) Benzylamine. The procedure used to prepare compound (21) was adopted to give the benzylamino-adduct, methyl 3- benzylamino-4,6-0-benzy~idene-3-deoxy-a-~-lyxo-(or xylo-) hexopyranosiduluse phenylhydrazone (27) (0.19 g, 7373, from the phenylazo-alkene (19) (0.2 g) and benzylamine (1 ml) in DMF (4 ml). The adduct had m.p. 132-1 34 "C; vmx.3 290 and 1 560 cm-'; A,,,,, 283 nm (Found: C, 71.2; H, 6.7; N, 8.4. C27H29N304requires C, 70.6; H, 6.3; N, 9.1). (d) Sodium borohydride. Sodium borohydride (0.03 g) was added to a solution of compound (19) (0.2 g) in methanol (6 ml). T.1.c. (solvent c) indicated that the reaction was complete in 2 h. Methyl 4,6-0-benzylidene-3-deoxy-a-~-threo-hexo-pyranosidulose phenylhydrazone (28) (0.15 g, 74) was isolated and recrystallised from aqueous propan-2-01. It had m.p. 65-66 "C; vmax,3 290 and 1 590 cm-'; 281 nm; 6" 8.28 (I H, s, NH), 7.96-7.0 (total 10 H, m, 2 x Ph), 5.8 (1 H, s, 1-H),5.74 (1 H, s, PhCH), 4.6-3.52 (total 4 H, complex m, 4-, 5-, 6-, and 6'-H), and 3.04 and 2.98 (total 5 H, 2 over-lapping s, 3-H2 and OMe) (Found: N, 7.3.C20H22NZ04 requires N, 7.9). Acknowledgements We thank Drs. P. M. Collins and N. R. Williams for helpful discussions and Dr. G. Hajivarnava for technical advice. One of us (N. D.) is indebted to the British Council for financial support whilst this work was in progress. References 1 Part 7, G. S. Hajivarnava, W. G. Overend, and N. R. Williams, J. Chem. SOC.,Perkin Trans. I, 1982, 205. 2 P. M. Collins, D. Gardiner, S. Kumar, and W. G. Overend, J. Chem. SOC.,Perkin Trans. I, 1972, 2596. 3 P. M. Collins, D. Gardiner, S. Kumar, and W. G. Overend, J. Chem. SOC.,Perkin Trans. I, 1972, 2611. 4 P. M. Collins, S. Kumar, and W. G. Overend, Carbohydr. Res., 1972, 22,187. 5 P. M. Collins, J. R. Hurford, and W. G. Overend, J.Chem. SOC., Perkin Trans. I, 1975, 2163. 6 P. M. Collins, J. R. Hurford, and W. G. Overend,J. Chem. SOC., Perkin Trans. I, 1975, 2178. 7 P. M. Collins, W. G. Overend, and V. M. Racz, Carbohydr. Res., 1975,45, 127. 8 M. Gyr and T. Reichstein, Heh. Chim. Acta, 1945, 28, 226. 9 G. J. F. Chittenden, Carbohydr. Res., 1971, 16, 495. 10 F. A. Carey and K. 0. Hodgson, Carbohydr. Res., 1970, 12, 463. 11 L. B. Lynda, G. S. Vernon, and V. E. Roberts, Carbohydr. Res., 1979, 69, C1. 12 S.A. Abbas and A. H. Haines, Carbohydr. Res., 1975, 39, 358. 13 A. Ya. Veinberg, A. M. Berdichevskaya, M. G. Edelev, G. I. Roslovtseva, I. N. Gracheva, and G. I. Samokhvalov, J. Gen. Chem. USSR (Engl. Trand.), 1974, 44, 867. 14 K. E. Pfitzner and J. G. Moffatt, J.Am. Chem. SOC.,1965, 87, 5661, 5670. 15 B. R. Baker and D. H. Buss, J. Org. Chem., 1965, 30, 2304, 2308. 16 P. J. Beynon, P. M. Collins, and W. G. Overend, J. Chem. SOC. C, 1969, 272. 17 R. F. Butterworth, P. M. Collins, and W. G. Overend, Chem. Commun., 1969, 378. 18 J. Parrick and J. W. Rasburn, Can. J. Chem., 1965, 43, 3453. 19 See E. Grundemann, Angew. Chem., Int. Ed. Eng!., 1969, 8, 459. 20 A. J. Fatiadi, Carbohydr. Res., 1968, 7, 89. 21 M. L. Wolfrom, G. Fraenkel, D. R. Lineback, and F. Komitsky, . Jr., J. Org. Chem., 1964, 29, 457. 22 D. C. Iffland, M. P. McAneny, and D. J. Weber,J. Chem. SOC.C, 1969, 1703. 23 Yu. P. Kitaev. B. I. Buzykin, and T. V. Troepol'skaya, Vsp.Khim., 1970,39, 961 (Chem. Abstr., 1970,73, 130346k). 24 H. El Khadem, Z. M. El Shafei, and M. M. Mohammed-Ali, J. Org. Chem., 1964, 29, 1564. 25 H. S. Blair and G. A. Roberts, J. Chem. SOC.C, 1967, 2425. 26 G. J. F. Chittenden and R. D. Guthrie, J. Chem. SOC.C, 1966, 695. 27 G. J. Karabatsos, R. A. Taller, and F. M. Vane, J. Am. Chem. SOC.,1963, 85, 2326. 28 N. K.Kochetkov and 0. S. Chizhov, Adu. Curbohydr. Chem., 1966, 21, 39. 29 0.S. Chizhov, L. S. Golovkina, and N. S. Wulfson, Curbohydr. Res., 1968, 6, 138. 30 M. Karplus, J. Chem. Phys., 1959, 30, 11. 31 S.Sternhell, Quart. Rev., 1969, 23, 236. 32 B. Coxon, Tetrahedron, 1965, 21, 3481. 33 R.D. Guthrie, A. M. Prior, and S. E. Creasey,J, Chem. Sac. C, 1970, 1961. 34 R. U. Lemieux and S. Levine, Can. J. Chem., 1964,42, 1473. 35 K. Igarashi and T. Honma, J. Org. Chem., 1967, 32, 2521. J. CHEM. SOC. PERKIN TRANS. I 1983 36 H. H. Baer and F. Kienzle, J. Org. Chem., 1969,34,3848; H. H. Baer, F. J. M. Rajabalee, and F. Kienzle, ibid.,p. 4204. 37 H. H. Baer and F. J. M. Rajabalee, Curbohydr. Res., 1970, 12, 241. 38 H. H. Baer and K. S. Ong, J. Org. Chem., 1969, 34, 560. 39 S. Kumar, Ph.D. Thesis, University of London, 1971; J. R. Hurford, Ph.D. Thesis, University of London, 1972; G. S. Hajivarnava, Ph.D. Thesis, University of London, 1974. 40 G. J. Robertson and R. A. Lamb, J. Chem. SOC.,1934, 1321. 41 J. W. H. Oldham and D. J. Bell, J. Am. Chem. Soc., 1938, 60, 323. Received 29th April 1982; Paper 2/703