1,3-Dipolar character of six-membered aromatic rings. Part XXVI. 3-Hydroxypyridine and 1-benzyl-3-oxidopyridinium

摘要

2334 J.C.S. Perkin I1.3-Dipolar Character of Six-membered Aromatic Rings. Part XXVI.3-Hydroxypyridine and 1 - Benzyl-3-oxidopyridiniumBy Julie Banerji, Nicholas Dennis, Judit Frank, Alan R. Katritzky,* and Taisuke Matsuo, School of Chemi-3- Hydroxypyridine undergoes successive 1.3-dipolar and Michael addition of acrylonitrile or methyl acrylate in highyield. These additions are thermally reversed, and 4-bromo-3-hydroxypyridine was prepared by adduct bromin-ation followed by retro-addition.cal Sciences, University of East Anglia, Norwich N R 4 7TJ1 -Benzyl-3-oxidopyridinium undergoes various 1.3-dipolar additions.THE N-substituent R in the pyridinium betaines (1) in solutions in polar solvents exists to a considerableprofoundly influences the ease of the cycloaddition extent in the betaine form (7).We therefore studied( 1 I( 2 ) R =CHiCHiCN(31 R = CHiCHi C02Me( A ) R = CH2Phreaction (1) -+ (5).2 We now report our work withthe betaines (1 ; R = H or PhCH,).Hydyogen as N-Substituent.-3-Hydroxypyridine (6)t N.m.r. data for compounds indicated in the Experimentalsection with a n asterisk are given in the supplementary Public-ation No, SUP 21797 (3 pp.). For details of SupplementaryPublications see Notice to Authors No. 7 in J.C.S. Perkin I,1975, Index issue.its reactions with various dipolarophiles. Acrylonitrilegave a mixture of endo- (8) and exo- (11) cycloadducts(1 : 1) in 90 yield, from which the exo-isomer (11)could be separated as pale yellow needles, m.p. 72-73 "C. The structures were demonstrated by elementalanalysis, i.r.and n.m.r.7 spectral data, and the formationof the 2,4-dinitrophenylhydrazone (13), m.p. 215-219 "C(from the epimeric mixture). The stereochemistry ofthe cycloadducts was elucidated by n.m.r. spectro-scopy. For both the exo-isomer (1 1) and the endo-isomer(S), the signal for the bridgehead proton H-1 appears asa doublet ( _ J ~ , J - ~ ~ ~ 7.5-8.0 Hz) irrespective of the1 Part XXV, N. Dennis, A. R. Katritzky, and R. Rittner,preceding paper.2 N. Dennis, B. Ibrahim, and A. R. Katritzky, J.C.S. PevkinI, 1976 2296.A. R. Katritzky and J. I. Lagowski, Adv. HeterocycZicChew., 19613, 1, 353; J. Elguero, C. Marzin, A. R. Katritzky, andP. Linda, The Tautomerism of Heterocycles,' Academic Press,New York, 1976, p.841976 2335stereochemistry, and that of H-5 is a doublet (J4,55.0 Hz) for the exo-isomer (11) and a quartet (J4,5 5.0,J5,6-ezo 6.0 Hz) for the endo-isomer (8). For the exo-isomer (ll), the H-6-endo signal is a quartet(Jt$-en,74,3 and J~-en,74nh), but for the endo-isomer (8),the H-6-ex0 signal is a doublet of triplets because ofsignificant additional coupling (J5,6-ero 6.0 Hz). In bothisomers, the H-7-exo signal is an octet and that of H-7-Each isomer displays a doublet oftriplets assignable to the N-cyanoethyl protons.a quartet.H 6 !LX(8) X:CN,R:CH$CHfCN191 X:C02Me,R :CHjCHiCOIMeC N113)0 O-IHfHI1 0) X :CN, R- Me(11 1 X CN, R :C+CHiCN(12 I X :C02Me,R C H i C H i C02Me- RI C H ~ C H RI141 R:CN15 I R : C OzMeSimilarly, reaction of 3-hydroxypyridine with methylacrylate produced a mixture of endo- (9) and exo- (12)cycloadducts (1 : 1) in 86 yield.Although thesestereoisomers could not be separated, their structuresand stereochemistry were demonstrated by elementalanalysis and i.r. and n.m.r. spectral data.The N-(2-cyanoethyl)- in (8) and ( l l ) and the N-(2-methoxycarbonylethyl) in (9) and (12) groups couldhave arisen by initial reaction of the zwitterion (7) toyield a cycloadduct ( 5 ; R = H) with an NH groupwhich subsequently reacted with a further molecule of theaddend by a Michael-type addition. Alternatively, theN-substituted betaines (2) and (3) could be the activeintermediates resulting from direct reaction between theaddend and the nitrogen atom of the substituted pyri-dine, with the initially formed zwitterions (14) and (15)undergoing tautomerisation to (2) and (3).Pyridinereacts with maleic acid,4 with acetylenedicarboxylates,5and with 9-benzoquinone to produce zwitterions.R. 31. Acheson, Adv. Heterocyclic Chem., 1963, 1, 125.E. de Barry Barnett, J. W. Cook, and E. P. Driscoll,K. Dennis, A. R. Katritzky, and M. Ramaiah, J.C.S.* 0. Lutz, Ber., 1910, 43, 2636.J . C h e m Soc., 1923, 123, 503.I'erkiTz I, 1975, 1506.However, our corresponding work in the phthalaziniumseries indicates that the cycloadduct formation isprobably the first step.The reactions of 3-hydroxypyridine with methylacrylate and acrylonitrile constitute simple, one-step,high-yield conversions into complex tropane-like com-pounds.Unfortunately, 3-hydroxypyridine is unre-active towards many other electron-deficient addends :N-phenylmaleimide, 2- and 4-vinylpyridine, diethylmaleate, fumarate, and azodiformate, phenyl vinyl anddivinyl ketone, methyl cinnamate, styrene, crotononi-trile, methacrylonit rile, met hacrylaldeh yde, phenyl pro-piolat e, t e t rac yanoe t h ylene, and f umaroni t rile.Reactions of 3-Hydroxypyridine Cycloadducts.-l,S-Dipolar cycloadditions are reversible thermally? photo-~hemically,~ and by electron impact.1° Both cyclo-adduct mixtures (8) + (11) and (9) + (12) undergoready retro-l,3-dipolar cycloaddition reactions underthermal conditions refluxing xylene (138 "C) or sublim-ation (120 "C at 1 mmHg) to yield 3-hydroxypyridine.We have attempted to exploit such retroreactions forthe synthesis of substituted pyridines.Hydrogenationof the isomeric cycloadducts (8) and (11) over Pd-Cgave the saturated product (16), which readily formedthe benzylidene derivatives (17) and (18) with benzalde-hyde. We failed to convert the benzylidene derivatives(17) and (18) into 4-benzyl-3-hydroxypyridine (19) bythermally induced double-bond migration to (22)followed by retro-l,3-dipolar cycloaddition.Treatment of the isomeric cycloadducts (8) and (11)with bromine in methylene chloride afforded the 3-bromo-derivatives (23) and (24) by bromination followedby dehydrobromination ; the exo-isomer (24) wasisolated.Sublimation of the exo-isomer (24) at 180 "C at1 mmHg yielded 4-bromo-3-hydroxypyridine (20) asCN bo(16)119) R:CH2Ph(20) R :Br(211 R:OHCNI221the quaternary salt (25) via a thermally induced retro-1,3-dipolar cycloaddition. However attempts to pre-pare 3,4-dihydroxypyridine (21) by treatment of the8 R. Hujsgen, H. Hauck, R. Grashey, and H. Seidl, Chem.Bey., 1968, 101, 2568.K. Burger and J. Fehn, Tetyahedron Lettevs, 1972, 1263.10 Y . Nomura, F. Furusaki, and Y . Takeuchi, J . Org. Chem.,1972, 37, 5022336 J.C.S. Perkin Ihydrogenated cycloadduct (16) with selenium dioxidefailed to produce the key intermediate 1,2-dicarbonylcompound (26). The keto-group of the cycloadduct type(5) is unreactive towards traditional carbonyl reagentsincluding Wittig and Grignard reagents, presumablybecause of steric hindrance by the N-CH,wCH,.CN group.Unreactivit y of ke to-groups in bicyclo3.3.1 nonan-3-ones has been reported.ll However, cyclopentadienemonomer underwent a Diels-Alder cycloaddition at theactivated 3,4-double bond of the exo-adduct (11) toyield the adduct (27).N.m.r. spectroscopy indicatesem-addition of cyclopentadiene (the H-1 signal is asinglet).1-Benxyl-3-oxido~y~idiniu~.-Shapiro et aL12 reported1-benzyl-3-hydroxypyridinium bromide (28) and itsconversion into the hydrated 1-benzyl-3-oxidopyridinium(4) with sodium in propan-1-01-methanol, but no 1,3-dipolar additions have been described previously. Weprepared 1-benzyl-3-oxidopyridinium (4) in situ fromI-benzyl-3-hydroxypyridinium bromide l2 (28) and tri-ethylamine ; with acrylonitrile it yielded the isomericcycloadducts (29) and (30) (1 : 1) as shown by i.r.andn.m.r. The betaine (4) with the relatively unreactive l3addend, styrene, produces both the 6-endo-cycloadduct1-12(231 R':H,R2:CN~ 2 4 ) R ' - c N , ~ ~ = H (251CN1261 1271(31) the endo-stereochemistry follows from the H-5,-H-6 coupling (6.0 Hz) and the 6-exo-cycloadduct (32)J5,s 0 Hz. N-Phenylmaleimide reacts with thebetaine (4) to form exclusively the exo-cycloadduct (33)The cycloadduct mixture (29) and (30) was hydro-genated to the saturated compounds (34). Quaternis-ation of the isomeric mixture (29) and (30) unexpectedlyyielded (35), by dissociation of the benzyl iodide fromthe initial product followed by further methylation ofWe have previously shown l4 that 3-hydroxypyridinereacts with benzyne (prepared l5 by diazotisation ofanthranilic acid) to form 5,9-dihydro-lO-pheny1-5,9-11 T.Momose, S. Atarashi, and 0. Muraoka, TetrahedronLetters, 1974, 3697.l2 S. L. Shapiro, K. Weinberg, and L. Freedman, J . Amer.Chem. Soc., 1959, 81, 5141.l3 R. Huisgen, R. Grashey, and J. Sauer in ' The Chemistryof Alkenes,' ed. S. Patai, Interscience, London, 1964, p. S66.(J1.7 = J S . 6 = 0 H4.(10) *iminobenzocyclohepten-6-one (36). The adduct (36)with m-chloroperbenzoic acid yields compound (38)(39), m.p. 137-138 "C, for which i.r. and n.m.r. spectralICH2Ph1281R' bo(30 I RLCN,R~=H(31 I R'-H ,R2:Ph0 N R ~ ~ ~ ~ ~ (321 R':Ph,R2=HNC(35)data indicate the nitrone tautomeric structure (39).This reaction presumably proceeds via the intermediateN-oxide (37), which suffers cleavage of the C(5)-N bond(Scheme).L(361 (3711(39 1 I381SCHEMEEXPERIMENTALM.p.s were determined with a Reichert apparatus.Spectra were recorded with a Perkin-Elmer 257 gratingi.r.spectrophotometer, a Hitachi-Perkin-Elmer RMU-6Emass spectrometer, a Unicam SP 800A U.V. spectrophoto-meter, and a Varian HA-100 n.m.r. spectrometer. Com-pounds were purified until they were observed as singlespots by t.1.c. on silica gel GF 254.8-( 2-Cyanoethyl) -2-oxo-8-azabicycZo3.2.loct-3-ene-6-exo-and -6-endo-carbonitriZe, ( 1 1) * and (8) * .-3-Hydroxy-l4 N.Dennis, A. R. Katritzky, and S. K. Parton, J.C.S.Perkin I . 1976. 2285.l5 L. Friedman and F. M. Logullo, J . Amer. Chem. SOL, 1963,85, 15491976pyridine (9.5 g, 0.1 mol), acrylonitrile (90 ml), and hydro-quinone (20 mg) were heated under reflux for 25 h. Theexcess of acrylonitrile was removed (40 "C at 5 mmHg),and the cooled residue twice chromatographed aluminiumoxide, type H ; CH,Cl,-light petroleum (b.p. 40-60 "C)(3 : 1) and then CH,C12 t o give a yellow viscous oil (18.1 g,90) (n.m.r. shows endo : exo ratio 50 : 50).The mixed adducts (0.30 g) in Et20 (170 ml) after a fewdays at 0 "C deposited the exo-cycloadduct (11) as paleyellow needles (0.092 g, 30), m.p. 72-73 "C (from Et,O)(Found: C, 65.8; H, 5.5; N, 20.7.C1,HllN,O requiresC, 65.7; H, 5.5; N, 20.9); v,, (Nujol) 2 244 (m) and1 690 cm-1 (a,p-unsat. ketone G O ) ; LX. (EtOH) 222 nm(log E 2.95); m/e 201. Attempts to isolate the pure endo-cycloadduct (8) from the mother liquors failed, but gave anenriched mixture (n.m.r. endo : exo ratio 60 : 40) which wasused for the n.m.r. study.The mixed cycloadducts (0.94 g, 0.004 7 mol), 2,4-dinitrophenylhydrazine (0.92 g, 0.004 7 mol), EtOH-tetrahydrofuran (2 : 5, 70 ml), and conc. HC1 (2 drops) werestirred at room temp. for 10 h. The solid was washed withEtOH (5 ml) and purified by preparative thick-layerchromatography (Kieselgel PF 254 ; tetrahydrofuran) t ogive orange needles (1.4 g, 80) of the 2,4-dinitrophenyZ-hydrazone (13) (from EtOH), m.p.215-219 "C (decomp.)(Found: C, 53.3; H, 4.2; N, 25.7. C17H15N70, requiresC, 53.5; H, 4.0; N, 25.7); m/e 381.Methyl 8-(2-IMetho.rycarbonyZethyZ)-2-oxo-8-azabicycZo-3.2.1oct-3-ene-6-exo- and -6-endo-carboxyZate, (12) * and(9) .*-3-Hydroxypyridine (9.5 g, 0.1 mol), methyl acrylate{SO ml), and hydroquinone (20 mg) were heated underreflux for 18 h. The excess of methyl acrylate was removed(40 "C at 5 mmHg) and the residue chromatographedaluminium oxide, type H; light petroleum (b.p. 60-80 "C)CH,Cl, (2 : 3)J to yield a yellow viscous oil (23.1 g, 86.5)containing the mixed (50 : 50) exo- and endo-cycloadducts(12) and (9) (Found: C, 58.4; H, 6.3; N. 5.4. C,,H,,NO,requires C, 58.4; H, 6.4; N, 5.2); v,, (film) 1725(ester G O ) and 1 685 cm-l (cr,p-unsat.ketone G O ) ; m/e 267.Retvo-l,3-dipoZar CycZoadditions.-(i) The mixed 8-(2-cyanocthyl)-2-oxo-8-azabicyclo3.2.loct-3-ene-6-exo- and-6-endo-carbonitriles (11) and (8) (50 : 50) (0.25 g , 1.3 x 10"11101) nere heated (120 "C at 1 mmHg) . 3-Hydroxypyridine(0.12 g, 98) collected on the cold finger as plates, m.p.129 "C (mixed m.p. 129 "C).(ii) The mixed methyl S-( 2-methoxycarbonylethyl)-2-oxo-8-azabicyclo3.2.loct-3-ene-6-exo- and -6-endo-carboxy-Iates (12) and (9) (50 : 50) (0.4 g, 1.5 x lo-, mol) wereheated (140 "C at 0.2 mmHg) as above to yield 3-hydroxy-pyridine (0.13 g, 95).8-(Z-Cyanoetlzyl) -2-oxo-8-azabicycZo3.2.loctane-6-exo- and- 6-endo-carbonitvile ( 16) .-The isomeric cycloadducts (8)and (11) (2.01 g, 0.01 mol) in EtOAc (250 ml) were shakenunder hydrogen at 20 "C over Pd-C (10; 100 mg) for 3 h.The solution was evaporated to yield the isomeric mixture(16) as a viscous oil (1.88 g, 90) which did not crystalliseand decomposed on distillation (Found : N, 20.7. C,,H,,-N30 requires N, 20.7); vmX.(fiIm) 2 238 ( E N ) and 1 725cm-l (sat. ketone G O ) ; m/e 203.3-Benzy Zidene- 8- (2-cyanoethyZ) -8-azabicyclo3.2.1 octane- 6-exo- and -6-endo-ca~bonitrit~ (18) * and (1 7) .*-NaOHsolution (0.5 ml; 5 ~ ) was added dropwise t o the cyclo-adduct (16) (1.0 g, 0.005 mol), and freshly distilled benzalde-hyde (0.53 g, 0.005 mol) in absolute EtOH (50 ml) wasstirred in a t 17-20 "C. After 2 h, the EtOH was evapor-2337ated off. The residue was taken up in CHCI, (50 ml) andthe solution washed with water (30 ml), dried (Na,SO,),and evaporated.The residual thick viscous oil (1.16 g,SOYo; endo : ex0 1 : 1 by n.m.r.) was separated by pre-parative t.1.c. Kieselgel PF 254; benzene-EtOAc (1 : l).The exo-nitrile (18) was obtained as yellow crystals, m.p.107-108 "C (0.58 g, 50) (EtOH) (Found: C, 73.8; H,5.8; N, 14.2. C,,H,,N,O requires C, 74.2; H, 5.9; N,14.4); vm, (CHBr,) 2 239 (EN), 1700 (ap-unsat.ketone GO), and 1 600 cm-l (C=C); A,, (EtOH) 208 (logt 3.204), 227 (3.398), 231 (3.380), and 301 nm (3.875);m/e 291. The endo-nitrile (17) formed a viscous gum(0.46 g, 40); vmx. (CHBr,) 2 240 ( E N ) , 1 700 (ap-unsat.ketone GO), and 1 598 cm-l (C=C) ; A,, (EtOH) 209 (log E3.69), 225 (3.68), and 300 nm (3.99); m/e 291.4-Brorno-8-( 2-cyanoethyZ)-2-oxo-8-azabicycZo 3.2.lloct-3-ene-6-exo- and -6-endo-carbonitrile (24) * and (23) .-Bromine (2.6 ml, 5.1 x lo-, mol) in CH,C12 (100 ml) wasadded dropwise at 17 "C t o the mixed adducts (1 1) and (8)(10.05 g, 0.05 mol) in CH2Cl, (400 ml).The solution wasstirred at 17-20 "C for 4 h, and more bromine (2.6 ml) inCH,Cl, (100 ml) was then added. After 8 h, the solutionwas decanted and the orange gum dissolved in CHC1,(500 ml) ; this solution was washed with NaHCO,-H,O,dried (Na,SO,), and concentrated (to 50 ml). The yellowprecipitate was crystallised from EtOH to give the exo-bromo-derivative (24) (2.8 g, 20y0), as pale yellow needles,m.p. 130 "C (Found: C, 46.8; H, 3.8; N, 15.1; Br, 28.5.C,,H,,BrN,O requires C, 47.1; H, 3.6; W, 15.0; Br,28.6); vwx.(Nujol) 2 240 ( E N ) , 1 700 (wp-unsat. ketoneC=O), and 1 585 cm-l (C=C); a;lx. (EtOH) 250 nm (log E3.95); m/e 280.The endo-brorno-derivative (23) could not be separated.Reaction of 8-( 2-CyanoethyZ)-2-oxo- 8-aznbicy clo r3.2.11 oct-3-ene-6-exo-carbonitrile ( 1 1) with Cyc1opentadiene.-Thecycloadduct (11) (1.0 g, 2.6 x 10-3 mol) and an excess ofcyclopentadiene (monomer) (5 x low3 mol) in tetrahydro-furan (20 ml) were stirred for 14 days at room temp. Thetetrahydrofuran was removed under vacuum (50 "C at 12mmHg). The yellow gum was purified by thick-layerchromatography Kieselgel PF 254; benzene-EtOAc(3 : l) to give 12-( 2-cyanoethyl)-8-oxo- 12-azatetracycZo-7.2.13~6~02~7trtdec-4-ene-ll-carbonitriZe (27) * (0.34 g ,50) as prisms, m.p.140-144 "C (from EtOH) (Found:C, 71.6; H, 6.3; N, 15.4. Cl6HI7N,O requires C, 71.9;H, 6.4; N, 15.7); vmx. (CHBr,) 2 230 (EX) and 1 715cm-l (sat. ketone G O ) ; m/e 267.Retro- 1,3-diPolar Cycloaddition of Compounds (23) and(24).-A mixture of cycloadducts (23) and (24) (1.39 g,4.96 x lo-, mol) when heated (180 "C at 1 mmHg), gave,on the cold finger, the salt (25) (needles from water) (0.43 g,50), m.p. 295 "C (decomp; sealed tube) (Found: C , 33.8;H, 2.3; Br, 44.9; N, 8.1. C,,H,Br,N,O, requires C, 34.5;H, 2.3; Br, 46.0; N, 8.1); 6 (D,O) 7.7 (2H, d, J 7 Hz),8.60 (2 H, d, J 7 Hz), 8.64 (1 H, d, H-2', J 1 Hz), and 8.68(1 H, d, H-2, J 1 Hz) ; rn/e 186 (no M+).8-BenzyZ-2-oxo-8-azabicycZo C3.2.lloct- 3-ene- 6-endo- and - 6-exo-carbonitrile, (29) * and (30). *-N-Benzyl-3-hydroxy-pyridinium bromide l2 (28) (7.98 g, 0.03 mol), hydroquinone(0.05 g), and Et,N (3.13 g, 0,031 mol) in acrylonitrile (60ml) were heated under reflux for 16 h. After cooling, theEt3N,HCl was filtered off and discarded. The filtrate wasevaporated to dryness and the resultant gum chromato-graphed (alumina; CH,CI,) to give the mixed endo- andexo-cycloadducts (1 : 1) (29) and (30) (3.7 g , 80) whic2338 J.C.S. Perkin Icould not be separated or crystallised (Found: C, 75.3;H, 5.9; N, 11.4. C15H14N20 requires C, 75.6; H, 5.9;N, 11.8); vmx. (Nujol) 2 230 (En'), 1692 (up-unsat.ketone G O ) , 1 490, 1 455, 730, and 695 cm-l (arom. C=C) ; LX.(EtOH) 218 nni (log E 4.049) ; rn/e 238.8-Benzyl- 6-endo- and - B-exo-phenyl- 8-azabicyclo 3.2.11 -oct-3-en-2-one, (31) * and (32) .*-N-Benzyl-3-hydroxy-pyridinium bromide (28) (3.0 g, 0.011 mol), hydroquinone(0.05 g), styrene (37 g , 0.3 mol), and Et,N (3 ml) in tetra-hydrofuran (60 ml) were heated under reflux for 48 h.The filtrate was evaporated (40 "C at 12 mmHg) and theresidue was chromatographed on alumina Brocknianngrade 1, neutral (100 g); toluene-EtOAc (2 : l). Theeluate was evaporated and the resultant yellow gum(1.8 g, 80) separated by preparative t.1.c. KieselgelPF 254; benzene-EtOAc (9 : l). The exo-6-phenyl cyclo-adduct (32) (0.1 g , 3.3) was isolated as yellow needles,m.p. 1OP-106 "C (from EtOH) (Found: C, 82.5; H, 6.5;N, 4.8.C,,H,,NO requires C, 83.0; H, 6.6; N, 4.8);vmX. (CHBr,) 1 679 (ap-unsat. ketone G O ) , 1 600, and 1 500cm-l (benzene C=C); La, (EtOH) 218 nm (log E 3.97);nz/e 289. The endo-6-phenyl cycloadduct (31) (1.1 g, 36)was isolated as a wax-like solid, n1.p. 50 "C; vnlax. (CHBr,)1 680 (rxp-unsat. ketone G O ) , 1601, and 1 499 cm-l (benzeneC X ) ; Amax. (EtOH) 218 nm (log E 4.017); m/e 289; picrate,n1.p. 156 "C (decomp.) (from EtOH) (Found: C, 59.4;H, 4.2; N, 10.8; C,,H,,N,O, requires C, 60.2; H, 4.3;N, 10.8); vlmAx (CHBr,) 3 380 (phenol O-H) and 1 705cm-l (ccp-unsat. ketone GO).ilfethylation of S-Benzyl-2-oxo-8-azabicyclo3.2.1oct-3-ene-6-endo- nnd -6-exo-carbonitrile, (29) and (30) .-The isomericmixture (29) and (30) ( 1 g, 0.004 mol) in MeCN (20 ml) wastreated with Me1 (10 ml) at 20 "C for 30 days.The quater-nary salt (35) was obtained as yellow needles (200 nig,12.5y0), m.p. 150 "C (from MeCN) (Found: C, 39.7; H, 4.7;N, 9.0; I, 37.6. C,,Hl,IN,O requires C, 39.5; H, 4.3; N,9.2; I, 41.7); vmaX. (Nujol) 2 240 (CEN) and 1 710 cm-l(ap-unsat. ketone G O ) .8-Benzyl-2-oxo-8-asabicyclo3.2.loctane-6-exo- and -6-endo-carbonitrile (34) .-The cycloadduct mixture (29) and(30) (1.19 g, 0.05 mol) in absolute EtOH (50 ml) was hydro-genated at 20 "C over Pd-C (10; 50 mg) for 3 h. Thesolution was evaporated to yield the hydrogenated corn-pounds (34) as a pale yellow viscous oil (0.94 g, 79)which could not be crystallised (Found: C, 74.0; H, 6.8;N, 11.4. C15H,,N,0 requires C, 75.0; H, 6.7; N, 11.7);vmax (film) 2 230 (C-N), 1725 (sat.ketone GO), 1490,1 450, and 695 cm-I (arom. C=C) ; m/e 240.8-Benzyl-2-oxo-8-azabicyclo3.2.loct-3-ene-6-exo, 7-exo-N-phenyldicarboximide (33). *-N-Benzyl-3-hydroxypyridi-nium bromide (28) (2.66 g, 0.01 rnol), N-phenylmaleimide(1.9 g, 0.011 mol), and Et,N (1.11 g, 0.011 mol) in tetra-hydrofuran (20 ml) were heated under reflux for 47 h. Thefiltrate was concentrated (40 "C at 12 mmHg) and the residue(2.35 g, 65.5) was separated by thick-layer chromato-graphy Kieselgel PF 254; benzene-EtOAc (4 : 1) (twodevelopments). The exo-cycloadduct (33) was isolated aspale yellow needles, m.p. 134 "C (from EtOH) (Found: C,73.3; H, 5.0; N, 8.0. C,,H1,N,O, requires C, 73.7; H,5.1; N, 7.8); v,, (CHBr,) 1715 (imide G O ) , 1675(ap-unsat. ketone GO), 1 600, and 1500 cm-l (benzeneC=C) ; Lx. (EtOH) 218 nm (log E 4.006) ; vn/e 358.Reaction of 5,g-Dihydro- 1 O-phenyl- 5 , g-iminobenzocyclo-Izepten-6-one (36) with m-Chloroperbenzoic Acid.-The cyclo-adduct (36) (1.3 g, 5.2 x mol) and m-chloroperbenzoicacid (0.91 g, 6.6 x lo-, mol) in CH,Cl, (100 ml) were stirredat 22 "C for 30 niin. The mixture was washed with 50;NaHCO, (20 ml) followed by water (20 ml), dried (Na,SO,),and evaporated, and the residual red oil was chromato-graphed (alumina; CH,Cl,) to give compound (39) (0.58 g ,42) as orange plates, m.p. 137-138 "C (from MeOH)(Found: C, 78.1; H, 4.8; N, 5.3. C,,H,,NO, requiresC, 77.6; H, 5.0; N, 5.3).We thank Dr. E. Lunt (May and Baker, Dagenhani) fordiscussions. We are grateful to the Chinoin Pharmaceuticaland Chemical Works Ltd., Budapest, Hungary, andTakeda Chemical Industries Ltd., Osaka, Japan, for leaveof absence to J. F. and T. M., respectively.5/2476 Received, 18th December, 1975