1646 J.C.S. Perkin I Organic Synthesis with Sulphones. Part 142 Nucleophilic Substitution on Styryl Sulphones ; a New Route to Arylacetaldehydes By Marc Julia," Anne Righini, and Daniel Uguen, Laboratoire de Chimie de I'Ecole Normale Superierue, 24 rue Lhomond, 75231 Paris Cedex 05, France Condensation.of sulphones with aromatic aldehydes in an alkaline medium readily gives P-hydroxy-sulphones which can be dehydrated to p-styrylsulphones. When these are treated with one molar equivalent of sodium alkoxides in dimethyl sulphoxide at room temperature, P-alkoxystyrenes are formed by ready nucleophilic substitution. Treatment of the hydroxy-sulphones directly with an excess of sodium methoxide leads to the corresponding dimethyl acetals. This is a new and potentially useful way to prepare arylacetaldehyde derivatives.P-OXYSTYRENEderivatives are equivalent to aryl-It seemed possible to write a similar sequence of acetaldehydes. These compounds are not so very easily reactions with sulphones instead of sulphoxides. In the prepared; on the other hand, they are interesting present work, a route leading from benzaldehydes to the starting materials for a variety of reactions, particularly enol ethers (9) is described. PhSOZR PhSO,-CH, *CH(OH)Ph PhSOZ*CH=CHPh PhCH2*CH(OMe)2 (1) (2) (3) (4) a; R = Me PhCH-CH-OR PhCH-CH-SAr b; R = Et (5) (6 1 a; R = Me a; Ar = ph b; R = Hex b; Ar = 4-Tolyl C; R = PhCH2. CH=CRI.S02Ph bsol; CH2-CH(OMeamp; bsol;CmCR1 R4 0R4 / 2 R4a2 R3 R3 R3 R3 R3 (12 ) (13 1 (141 in the heterocyclic series.In the course of other work, it The first two steps (1) and (2) are well documented. had been found that benzyl alcohol gives a high yield of Sulphones and aldehydes can be condensed under a tram-P-benzyloxystyrene (5c) when submitted to strongly variety of basic conditions to hydroxy-sulphones which basic, mildly oxidising conditions,2 a reaction thought to can be dehydrated to styryl sulphones under acidic or involve first oxidation to benzaldehyde and then croton- basic conditions. In some cases, the two reaction steps isation with dimethyl sulphoxide to give p-methyl- can be carried out in one flask under the influence of a 5sulphinylstyrene; addition of benzyl oxide anion phase-transfer cataly~t.~, followed by elimination of methyl sulphenate anion Reactions (3) and (4), equivalent to nucleophilic would then account for the result.This has been shown substitution at a vinylic centre with sulphinate anion to be a possible route to (5).3 G. Cardillo, D. Savoia, and A. Umani-Ronchi, Synthesis, Part 13, M. Julia and D. Deprez, Tetrahedron Letters, 1976, 1975, 453. 279. 5 (a) W. E. Truce and V. V. Badiger, J. Amer. Chem. Soc., 2 H. Langhals, M. Julia, and D. Mansuy, Tetrahedron Letters, 1964,86, 3277; (b)W. E. Truce and C. T. Goralski, J. Org. Chem., 1976, 3516, 1971, 56, 2536; (c) L. Field, J. Amer. Chem. Soc., 1952, 74, 3919. Unpublished work. G. Modena, Accounts Chem. Res., 1971, 4, 73. as leaving group would be, of course, the crucial part. The chemistry of vinyl sulphones, including nucleo- philic displacement of other leaving groups, has been OHI PhCHO + CH,-S0,Ph PhCH*CH,-S0,Ph (1) (2) YhCH(OH)*CH,*SO,Ph PhCH=CH*SO,Ph (2) (3) ORI PhCH=CH*SO,Ph + RO-PhCH*CH*SO,Ph (3) ORI PhcH*CH*SO,Ph PhCH=CH*OR+ PhS0,-(4) (5) thoroughly investigated by Stirling and his group but displacement of the sulphinate anion is not very common. discussion has been described see equation (6).lZa In this case, however, an addition-elimination mechanism RS-+ R-SO2*CH=CH*C0,Et+ RS*CH=CH*CO,Et+ RS0,-cannot be expected to operate.12a, Trialkylboranes bring about the displacement of a vinylic sulphonyl group by an alkyl group; l3 the mechanism of this reaction is thought, however, to be a free-radical one.Considering that the addition of alkoxide ion p to the sulphonyl group would be reversible, it was hoped that occasionally the addition would occur in the reverse direction (3) the irreversible formation of phenyl sulphinate ion so formed then ensuring that the reaction went to completion. TABLE1 Preparation of styryl sulphones and P-hydroxyphenylethyl sulphones Procedure A Yield 74(I M.p. 74("C) C 75 63 B 64 120.5 B 76 120 B 71 106 B 88 103 B 72 94.5 B 78 90 B 90.5 94 euro;3 76 107 B 83 102 The corresponding aromatic nucleophilic substitution is involved in the Smiles rearrangement see equation (5).*? Lit. m.p. Found Required ("C) Ref. Formula () ()73.5-75 5a 6G65 5a S11.63 S11.66C1t5H1403S S11.7 S11.66C16H1403S S11.37 S11.50C14H11C102S Cl,Hl*OZS S10.77 S11.18 94.5-95.5 5b Cl*Hl,O,S S10.73 s11.10 92-94 5c s10.02 S9.68C14H1ZC1203S C13H13R03S S11.98 S12.15 p-Styryl sulphones (3) and a series of substituted derivatives were prepared (Table 1) according to liter- ature procedures, starting with aromatic aldehydes and phenyl methyl (la) or phenyl ethyl (lb) sulphones; the ~*CHd,.CH,0'O.CH,,.CH,~; (5) ,?-configuration about the double bond was ascertained by n.m.r.The Z-isomer of P-styryl sulphone (3) was prepared by oxidation of the corresponding sulphide. The olefinic sulphones were then submitted to the original two sets of reaction conditions: when treated with benzyl alcohol and solid potassium hydroxide in dimethyl sulphoxide, the E-styryl phenyl sulphone E-(3) did not give the corresponding vinyl ether (5a) but phenyl methyl sulphone (la) which, instead, could be isolated in 180/, yield; apparently reactions (2) and (1) had taken place in the reverse direction.However, in the presence of dry sodium benzyl oxide in dimethyl lo F. G. Bordwell and W. H. McKellin, J.Amer. Chem. SOC., 1950, 72, 1985; F. G. Bordwell, R. D. Chapman, and W. H. McKellin, ibid., 1954, 76, 3637. l1 W. E. Truce and F. E. Roberts, jun., J. Org. Chem., 1963,28, 593. l2 (a) M. L. Oftedahl, J. W. Baker, and M. W. Dietrich, J. Org.Chem., 1965, 30, 296; (b) J. E. Baldwin, J. Critting, W. Dupont,L. Cruse, L. Silberman, and R. C.Thomas, J.C.S.Chem. Comm., 1976, 736. l3 H. Nozaki, Bull. Chem. SOC.Japan, 1974, 47, 503. NO2 The addition of alkoxide ion in reaction (3) would, of course, be expected to take place in the reverse direction leading to the more stable a-sulphonyl carbanion. This has been shown lo to be the case in the base-catalysed addition of thiols to benzothiophen dioxide while the free-radical initiated addition takes place in the reverse direction. The sulphinic acids are prepared efficiently by nucleophilic displacement in some vinyl sulphones ;l1 the desired direction of addition being facilitated by an ester group. A remarkable reaction of the type under 7 See for instance N. K. Barlow, D. R. Marshall, and C. J. M. Stirling, J.C.S. Perkin 11, 1977, 1920 and previous papers in this series, particularly C.J. M. Stirling, J. Chem. SOC.,1964, Suppl. I, 5875; M. J. v. d. Sluijs and C. J. M. Stirling, J.C.S. Perkin 11, 1974, 1268. 8 W. E. Truce, E. M. Kreider, and W. W. Brand, ' OrganicReactions,' Wiley, New York, 1970, vol. 18, p. 99. K. B. Tonier and A. Weisz, Tetrahedron Letters, 1976, 231. sulphoxide for a few hours at room temperature, the sulphone E-(3) was converted (65yo) into the E-p-benzyloxystyrene E-(5c). It should be pointed out that only the E-isomer of P-benzyloxystyrene was formed as in the original work.2 When the isomeric sulphone 2-(3) was submitted to the same reaction J.C.S. Perkin I The difficulty associated with dehydration of the hydroxy-sulphones (8) bearing an ortho-methoxy-sub-stituent could be avoided by methylation (see Experi-mental section).Hence with an excess of sodium methoxide the P-methoxy-sulphone (12) gave the corresponding methyl vinyl ether (9c). The sulphones TABLE2 Reactions of various sulphones with sodium alkoxides in dimethyl sulphoxide fl-styryl ether Arylacetaldehyde acetal Arylacetylenic compound Starting material Styryl sulphone E-(3) Sodiumalkoxide NaOMe Compound E-(5a) Yield () 65 * NaOHex n NaOCHaPh E-(5b)E-(~c) 60-62 63-65 NaOCHpPh E-(5c) 65 NaOMe NaOMe E-(9a)E-(9b) 68 10 t NaOMe E-(9d) 63 NaOMe (99 8 22 NaOMe (9g)4 22 NaOMe Yield YieldPhys. consts. Compound () Phys. consts. Compound (yo) Phys. consts. B.p.38-41 "C at 0.2 T 61it.l' 208-209 C at 99 T)B.p. 90 "Cat 0.7 T M.p. and m.m.p.43 "C (Wa43 "C)M.p. and m.m.p.43deg;C(lit.2430C)B.p. 88 "Cat 0.5 T B.p. 67-72 "C at 1 0.2 T B.p. 66-68 "C at 0.2 T B.p. 100-110 "C at 0.2 T B.p. 80-85 "C at 11 B.p. 53-55 "C at 10 T 20 T)0.2 T(Iit.l.86-"C at (lit.,I6 90 92 "C at 1T) 70 * B.p. 66 "C at 0.3 T (lit.,1a 115-117 OC at 3 T)8-Hydroxysulphone(2) NaOMe 'I E-(5a) 31 ll 12 II ( 7C) NaOMe 7 70 * B.P. 98 ocat 0.8 T (13)(13) NaOMe 7 68 B.p. 80 "C at 0.2 T 8-Methoxysulphone (12)(12) NaOMe 7 E-(9c) TO * B.p. 100-101 "C at 0.2 T * N.m.r. showed the crude product to be practically pure. Purification by column chromatography (silica gel-pentane) prior to distillation. $ Not isolated but charac-terised by comparison of mass spectra with literature data.'' 8 Stereochemistry not determined.11 Same retention in g.1.c. (SE30, DC550) as an authentic sample. 7 Athree-fold excess of sodium methoxide was used. conditions the same E-ether was obtained in a similar yield. This is not really surprising; although nucleo-philic substitution of vinylic halides usually occurs with retention of configuration,6 displacement of Me0 by PhO in E-and 2-phenoxyvinyl sulphones has been shown to lead to the same E-methoxyvinyl sulphone.' The sulphone E-(3) was then treated with sodium methoxide or sodium n-hexoxide in dimethyl sulphoxide : the corresponding vinyl ethers (5a) and (5b) were isolated in a similar yield. Again only E-isomers were formed.A number of substituted styryl sulphones (8)were then treated with sodium methoxide in dimethyl sulphoxide (Table 2) when the corresponding styryl methyl ethers (9) were formed. In some cases it proved advantageous to treat the hydroxy-sulphone itself with an excess of sodium methoxide in dimethyl sulphoxide, the dimethyl acetals of the corresponding arylacetaldehydes being obtained in good yields. This latter procedure is one step shorter and the acetals are more stable than the vinyl ethers. Acetal formation is not surprising in view of the known ability of vinyl ethers to add alkoxides.l* This must be greatly facilitated when the aromatic moiety is parti-cularly apt to stabilise a negative charge on the a carbon atom. l4 E.Taskinen and P. Ylivainio, Acta Chem. Scand., 1975, 329, 1. l6 C. 33. Hurd and A. Tockman, J. Org. Chem., 1958, 23, 1087. 16 G. I. Hobday and W. F. Short, J. Chem. Soc., 1943, 609. 17 S. Safe, J. Gem. SOL, (B),1971, 962. bearing an a-methyl substituent in the styrene moiety (8g and h) gave variable amounts of the corresponding acetylene derivatives (1lg and h). The question arises as to whether the styryl ethers (9) could have been formed from the sulphones (8) by a path involving elimination to give the arylpropynes (11) followed by addition of methanol. It is known l9 that addition of alcohols to acetylenes readily occurs in the presence of base. The stereochemistry of the adducts is however 2 whereas the vinyl ethers obtained from the vinylic sulphones (8) have consistently the E-configuration.Moreover, methanol and hexanol add smoothly to phenylacetylene (see Experimenta1 section) whereas benzyl alcohol fails to add under the same reaction conditions. Other nucleophiles were tried in the nucleophilic substitution of the sulphonyl group of the styryl phenyl sulphone (3). Benzene and toluene-9-thiolates led to the corresponding thioethers (6) in ca. 30 yield. Addition of a catalytic amounts of cuprous iodide-tributylphosphine doubled the yield. Under free radical initiation thiols also gave the thioether (6) (26 yield). Attempts to use other nucleophiles have been un-successful, so far : potassium phthalimidate, sodium N-methyl N-phenylamide, and potassium acetate failed to give substitution products.Nucleophilic substitution by methoxide of the sul-18 H. Tsuruta, K. Tomisawa, and T. Mukai, Bull. Chem. Soc. Japan, 1972, 45, 1584. 19 W. Reppe, Annalen, 1956, 601, 81; see also S. Miller, .J. Anier. Chem. Soc., 1956, 78, 6091. 1978 phony1 group in the readily available sulphones (7) or (8) thus represents a simple procedure to produce aryl acetaldehyde derivatives from benzaldehydes. This compares favourably with known procedures including a recently published route 2o using methylthiomethyl sulphoxide. It should be pointed out that in the sulphone route the elimination step gives a sulphinate salt back which can be recycled.21 EXPERIMENTAL All the reactions were run under an atmosphere of dried argon.Melting and boiling points are uncorrected. N.m.r. spectra were obtained using a Varian A 60 spectrometer in CDC1, solution with SiMe, as an internal standard; their descriptions (6, J/Hz) use the following abbreviations : s = singlet, d = doublet, m = multiplet, b = broad. U.V. spectra were recorded on a Beckman DK 2A apparatus and i.r. spectra on a Perkin-Elmer 257 spectrophotometer. Mass spectra were obtained for solids on a Varian Mat CH7 apparatus and for liquids on a Mat I11 coupled with g.1.c. (OV 17). G.1.c. analyses were run on a Intersmat GC 120 SL chromatograph. T.1.c. analyses or preparative separ- ations (p.1.c.) were performed on silica gel PF 254; solvent: CH,Cl,-cyclohexane-ethyl acetate (50: 50 : 10; v/v).Sol-vents were dried by conventional methods : dimethyl sulphoxide (DMSO) and methylene chloride were distilled from calcinni hydride, tetrahydrofuran (THF) , and ether from benzophenone-sodium, dimethylformamide (DMF) , pentane, cyclohexane, and benzene from P205. 2,4-Dinitrophenylhydrazones(DNP) of both enol-ethers and acetals were obtained bv treatment with a molar equivalent of 2,4-dinitrophenylhydrazine in ethanolic perchloric acid solution. After 24 h at room temperature the coloured precipitates were filtered off and washed with water until neutral. T.1.c. analysis of the crude compound so obtained showed their homogeneity; purification for analysis was effected by recrystallisation from ethanol- methylene chloride and drying in vacuo.Phenyl methyl sulphone (la) and phenyl ethyl sulphone ( lb) were prepared by published procedures.22 Synthesis of cis-Uwsaturated Su1phones.-Three general procedures were used. Procedure A. Condensation of an alkyl phenyl sulphone with an aromatic aldehyde with phase-transfer catalysis according to the procedure of Umani-Ronchi., At the end of reaction (controlled by t.l.c.), the necessary excess of aldehyde was removed by distillation under reduced pressure. The crude product crystallised on trituration in ether. Filtration on silica gel (methylene chloride), followed by recrystallisation from carbon tetra- chloride, gave a pure product. Procedure R. Condensation of the lithiated sulphone with the carbonyl derivative according to published pro-cedures 23a9b followed by dehydration of the intermediate hydroxy-sulphone by means of 85 H3P0,.6C After hydrolysis (ice-water) , the unsaturated sulphones (generally crystalline at this stage) were filtered off, washed with water, recrystallised twice from MeOH, and dried in vacuo; yields were not optimised.2o K. Ogura, M. Yamashita, and G. Tsuchihashi, Synthesis,1975, 385. 21 C. E. Vennstra and B. Zwanenburg, Synthesis, 1975, 519. 22 C. M. Suter, ' The Organic Chemistry of Sulphur ', John Wiley, New York, 1944. Procedure C. Oxidation by H,O,-AcOH of the cor-responding ~ulyhide.~aj * P-Hydroxy Su1phones.--In some cases, the hydroxy sulphones (procedure B, see above) were purified by chromatography (see Table 1) (silica gel, solvent dichloro- methane) and then crystallised.TABLE3 N.m.r. and mass spectra data of styryl and P-hydroxy-sulphones Sulphone 6 Values (J in Hz) mle * (8a) t 6.7-8.15 (11 H, m), 3.82 (3 H, s) 132, 274 (M+),77, 209, 179 (8b) 6.67-8.15 (11 H, m in which d, J 16.5 at 6.8) 3.82 (3 H, s)(8d) 7.15-8.2 (lOH, in); 6.9 (1 H, d, 125, 243, 101, 75,J 15.5) 278 (M+) (8f) 6.6-8.2 (11 H, m), 2.9 (1 H, sept., 144, 129, 286 (M+),J 7); 1.25 (6 H, d, J 7) 271 (8h) 6.83-8.15 (10 H, m); 3.84 (3 H, 146, 77, 288 (M+),s); 2.14 (3 H, s) 103, 131, 115 (7e) 7.18-8.15 (8 H, m), 5.43 (1H, dd), 330 (M+),312 3.38 (3 H, b d-bs) (13) 7-8.7 (9H,m), 6.3 (1 H, bs, OH),5.2-5.5 (1 H, ni); 3.3-3.8 (2 H, m)* Mass spectra peaks in order of decreasing intensity.t vmeX,962 cm-l. O-Methyl Ether of 1-(2,3-Dimethoxyphenyl)-2-~henyZ-sulphonylethanol ( 12) .-One molar equivalent of methyl iodide in hexamethylphosphotriamide (10 ml) was added to the THF solution of the lithium alkoxide resulting from the condensation of the sulphone ( la) with 2,3-dimethoxy-benzaldehyde. The reaction mixture was stirred for 10 h at -10 to -20 "C then extracted to give a solid (yield 90). This was crystallised twice from ether to give (12) (yield 42) as white needles, m.p. 139.5 "C; n.m.r.: 6.75-8.2 (8 H, m), 5.1 (1H, dd), 3.75 (6 H, 2s), 3.5 (2 H, bd), and 3.18 (3 H, s); m/e 336 (M+). C,,H,,O,S = 336 (Found: S, 9.38. C,,H,,O,S requires S, 9.51). Preparation of ap-Unsaturated Sulphides (6) .-2-Sulphides were prepared according to literature procedure 5a by heating phenylacetylene with the sodium salt of the desired arenethiol in ethanol.Z-2-Phenylvinyl phenyl sulphide 2-(6a), m.p. 42-44 "C (from pentane) (lit.,6a 45 "C); 2-2-phenylvinyl p-tolyl sulphide Z-(6b), m.p. 65 "C (frpm pentane) (lit.,6a 64.5 "C). The corresponding E-sulphides were obtained by treating E-P-bromostyrene with the sodium salt of the arenethiol in DMF for 6 h at 130 "C. After hydrolysis, extraction (ether), and evaporation of the solvent, the residue was distilled to remove unchanged brornostyrene. E-2-phenylvinyl phenyl sulphide E-(6a) had b.p. 135 "C at 0.3 Torr (lit.,5n 142-143 "C at 0.5 Torr), m.p. 28-29 "C; E-2-phenylvinyl P-tolyl sulphide E-(6b) had m.p.45 "C (from pentane) (lit. ,Sa 44-45 "C) . Preparation of an Authentic Sample of Z-Enol Ethers.- Treatment of phenylacetylene with the desired alkoxide in alcohol gives the title compounds. Attempts to prepare the Z-benzyl ether (5c) by this technique were unsuccessful ; no identifiable product was formed. Z-2-Phenylvinyl methyl ether Z-(5a), b.p. 44 "C at 0.2 Torr (lit.,24a 44 "C at 23 (a) W. E. Truce, T. C. Klingler, J. Ovg. Chem., 1970, 35, 1834; (b) J. M. Paris, Thesis, Paris, 1973. 24 (a) J. E. Baldwin and L. E. Walker, J. Org. Chem., 1966, 31, 3895; (b) R. Tanaka, M. Rodgers, R. Simonaitis, and S. I. Miller, Tetrahedron, 1971, 2651. 0.3 Torr); n.m.r. CH=CH J = 7 Hz (lit.,24b7 Hz); DNP; m.p. and mixed m.p.121 "C (from ethanol); Z-Z-phenyl- vinyl hexyl ether Z-(5b), b.p. 76 "C at 0.2 Torr, n.m.r.: CH=CH, J = 7 Hz; DNP, m.p. and mixed m.p. 121 "C (from ethanol). TABLE4 N.m.r. and mass spectra of enol ethers, acetals, and acetylenic compounds Crnpds 6 Values (Jin Hz) E-(5a) 7.42br (5H,s), 7.24 (1H, d, J 14),5.98 (1H, d, J 14), 3.76 (3 H, s) E-(5b) 7.43br (5H, s), 7.23 (1H, d, J 14),6.03 (1H, d, J 14), 3.97br (2H, t,J 7), 0.8-2 (11H, m) E-(5c) t Identical to literature values. E-(9a) 6.6-7.4 (5 H, m), 5.83 (1H, d, J 12.5). 3.78 (3 H, s),3.66 (3 H, s)E-(9b) 6.8-7.3 (5 H, m), 5.88 (1H, d, J 12), 3.78 (3 H, s), 3.67 (3 H, s) E-(9c) 6.62-7.33 (4 H, 111 in which d at 7.18 J 13.5), 6.06 (1H, d, J 13.5), 3.82 (6 H, s), 3.7 (3 H, s)E-(9d) 7.76 (5H, m in which d at 7.1 J 14),6.16 (1 H, d, J la), 3.38 (3 H, s) E-(9f) 6.5-7.2 (6 H, m), 3.58 (3 H, s),2.9 (1H, m), 1.18 (6 H, d, J 7) (9g) 7.3 (6 H, m), 3.66 (3 H, s), 2.04 (3 H, s)(loe) 7.2--7.5 (3 H, m), 4.62 (1 H, t, J 5.5), 3.35 (6 H, s), 3.04 (2 H, d, J 5.5)(llg) 7.38br (5 H, sf, 2.08 (3 H, s) (llh) 6.84-7.38 (4 H, AA'BB' 9), 3.76 (3 H, 4,2 (3 H, s) (14) 7.2-8.6br (4H, 2d), 4.6 (1H, t, J 6.5), 3.33 (6 H, s), 2.9 (2 H, d, J 6.5) mle * 135 (M-++ I), 134 (M+)204 (M+) 164 (M+) 194 (M+),136, 151, 91 1681170 (M-) 161, 176 (Mi),128, 91, 118 148 (M+),105, 43, 91, 133 75, 159 115, 116 (M+) 146 (M+) * Mass spectra peaks in order of decreasing intensity.t kman.(EtOH) 207 nm (L 22 000) (lit.,2 207 nm).N.m.r. spectrum agrees well with literature data.25 Reactions of a,p-Unsaturated Sulphones witla Sodium A lkoxides.-General procedure. The desired alcohol ( 10-2 mol) was added to a suspension of one molar equivalent of J.C.S. Perkin I ml).* The resulting grey slurry was stirred for 16 h at 24 "C. An M-solution of the unsaturated sulphone in dimethyl sulphoxide (10 ml) was added dropwise over 15 min. The coloured mixture was stirred for 48 h at room temperature, and then poured into ice-water and extracted with methylene chloride (3 x 50 ml). The organic layers were thoroughly washed with water and then dried (K,CO,) . Evaporation of solvent followed by short-path distillation (bulb tube) gave the ethers which are relatively unstable and were, after structural determination (Table 4), trans-formed into the DNP derivatives (Table 5).Reaction of E-Styvyl Phenyl Sulphone (3) with Thiols (Sodium Salts) .-Sodium salts of aromatic thiols were pre- pared by addition of mole of either benzene- or toluene- p-thiol to one molar equivalent of sodium hydride in DMSO (10 ml). After release of hydrogen (1 h), the sulphone ( rnol), with or without added cuprous iodide-tributyl- phosphine ( rnol), in DMSO (10 ml) was rapidly added. The mixture was stirred for 8 h at 100 OC, hydrolysed, and extracted (cyclohexane) . Filtration on a short column of silica gel and evaporation of the solvent, gave an oily residue, the n.m.r. spectrum of which was recorded; the oil was then distilled (bath temp.180 "C, 0.3 Torr) ; crystallisation was then induced by trituration under pentane. Reaction with benzenethiol (without cuprous ions) gave in 34 yield (b.p. 138 "C at 0.1 Torr) E-styryl phenyl sul- phide (6a) retention time on g.1.c. (SE 30) ; n.m.r. and mass spectra as authentic (see above). Reaction with toluene-p-thiol (without cuprous ions) gave in 30 yield E-(6b), m.p. and mixed m.p. 45 "C. Reaction with toluene-p-thiol (with added cuprous ions) gave in 70 yield E-(6b), m.p. and mixed m.p. 45 "C; n.m.r. on the crude product CHxCH, 6 6.63br (d) indicated the absence of the Z-isomer (6 6.32, s); g.1.c. (SE 30) showed the presence of a small impurity which was found to be P-tolyl disulphide m/e 246 (M+).Reaction of E-Styryl Sulphone (3) with Thiols under Free- radical Conditions.-The sulphone (3) (1.22 g, 5 x mol) thiophenol (1 ml, 10-2 mol, distilled under argon TABLE5 DNP derivatives of the corresponding arylacetalclehydes obtained from either enol ethers or acetals DNP yield Lit. m.p. Substrate (yo) M.p. ("C) ("C) Ref. Formula Found Required E-(5a) 100 120 t E-(5b) 100 120-121 t E-(5c) 100 121 t (94 100 137 134 26c (9b) 79 132 137 26b (94 76 151 136-137 27 Cl,Hl,N,O, N16.36 N15.55 (94 82 135 134-136 26a (9f) 91 119.5 C17H18N404 N16.2 N16.35 (9g) 82 149.5-100 t (1Oe) 100 217-218 Cl,H,,C12N,04 N15.35 N15.15 (14) 89r 226-230 C12Hl,C1N50, N17.6 N17.45 (dec.) mle * 91, 136, 162, 360 (M+) 117, 155, 133, 342 (M+),307 159, 152, 161, 368 (M+)104, 92, 301 M+-(HC10,) * Mass peaks in order of decreasing intensity.sodium hydride (0.48 g of a 50 dispersion of sodium hydride in oil washed twice with pentane) in DMSO (10 * In one case the reaction of sodium benzyl oxide with the styryl sulphone (3) dimethylformamide was substituted for the dimethyl sulphoxide but since it gave a poorer yield, it was not further used. 25 P. Gramatica, D. Monti, and P. Manitto, Gazzetta, 1974, 104, 629. 7 M.p. and mixed m.p. just before use), and azobisisobutyronitrile (200 mg) were stirred for 10 h at 60 "C, then for 16 h at 25 "C in benzene (10 nil). The resulting homogeneous solution was washed 26 (a) G. Signarella, L. Mariani, and E. Testa, Gazzetta, 1965, 95, 831; (b) R.B. Lotfield, J. Amev. Chem. SOC.,1950, 72, 2499; (c) A. K. D. Guptaand J. K. Chakrabarti, J. Scz. Ind. Res. India, 1961, 20B,394. 27 A. I. Meyers and J. C. Sricar, J. Org. Chem., 1967, 32, 4134. Perchlorate salt. with 5 sodium hydroxide (3 x 50 ml), dried over potas- sium carbonate, and evaporated. The residue (1.98 g) was a rather complex mixture (t.l.c., pentane) and was chro- matographed on silica gel (methylene chloride). This gave first 1.25g of an oil, then 0.7 g of unchanged sulphone (3). The oily fraction was again chromatographed (p.l.c., eluting three times with pentane) and gave four fractions. Two of these (0.26 g), which had the lowest retention times, were unidentified products and not further studied. The two others, with longer retention times, were well crystallised and identified (n.m.r., m/e, mixed m.p. with authentic samples) as being diphenyl disulphide (0.5 g) and E-2-phenylvinyl phenyl sulphide (6a) (0.11 g, 250/,, based on reacted sulphone) . Unsuccessful Substitution Reactions.-(a) With potassium phthalimidate. Heating of the sulphone (3) with one equimolecular amount of the potassium salt of phthalimide in DMSO at 80 "C for several hours gave unchanged (3). (b) With the sodium salt of N-methylaniline. Absence of any substitution product was confirmed by comparison (n.m.r.) of the reaction mixture with an authentic sample 28 of enamine. (c) With potassium acetate. Potassium acetate was melted before use. Compound (3) was recovered unchanged after several hours of heating. 8/381 Received, 18th March, 19781 28 P. Ramart-Lucasand J. Hoch, Bull. SOG. cham. France, 1936, 918; J. Hoch, Compt. rend., 1934, 199, 1438.
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