2562 J.C.S. Perkin IHeterocycles by Cycloaddition. Part 5 2 Preparation of 7,9-Diheteratri-cyclo[4.2.1 .02*5]non-3-en-8-one Derivatives f rom Mesoionic CompoundsBy H iroshi Matsukubo and Hiroshi Kato," Department of Chemistry, Faculty of Science, Shinshu University,Cycloaddition of a mesoionic dithiolone or thiazolone (1 ) with dimethyl tricycl0[4.2.2.0~~~]deca-3,7,9-triene-7,8-dicarboxylate (2) occurred at the cyclobutene ring. Thermal fragmentation of the adducts (3) or the correspondingS-oxides (6) gave dimethyl phthalate and the title diheteratricyclononenone derivatives (4) or their S-oxides (7).Asahi, Matsurnoto 390, JapanMESOIONIC compounds have found wide application inthe synthesis of a variety of heterocyclic systems.Apart from their well-established use in the preparationof five-membered heterocycles by cycloaddition-extrusion reactions with olefins and acetylenes,2 theyserve as starting materials for the preparation of six-membered heterocycles by cycloaddition-extrusion-ringexpansion reactions with small-ring olefins,3 and wehave recently reported a novel synthetic approach t oboth five- and six-membered aromatic heterocycles bycycloaddition-double fragmentation reactions of meso-ionic compounds with suitable bicyclic ole fin^.^^^ Inthis paper we describe the reactions of mesoionic com-pounds (1) with dimethyl tricyclo[4.2.2 .0 2 y 5] deca-3,7,9-triene-7,8-dicarboxylate (2), the adduct of cyclo-octa-t etraene and dimethyl acet ylenedicarboxylat e. Thisring system has three potentially available double bondsfor cycloaddition, and the cycloadducts, if formed, mayundergo fragmentation in a variety of ways.The reaction of the mesoionic 2,5-diphenyl-l,34ithiol-4-one (la) with the triene (2) slowly took place inrefluxing benzene to give one 1 : 1 adduct in quantitativeyield. The i.r., mass, and n.m.r.spectra combined witha decoupling experiment established that the additionoccurred at the most strained cyclobutene ring togivethe adduct (3a) (see later for configurational assignment).The reaction of the mesoionic 2,3,5- triphenylt hiazol-4-one (lb) with (2) proceeded more sluggishly, but gavethe corresponding adduct (3b) (43%). These results1 Part 4, H. Matsukubo and H. Kato, Bull. Chem. SOC. Jagan,1976, 46, 3314.2 M. Ohta and H.Kato, ' Nonbenzenoid Aromatics,' vol. 1,ed. J. P. Snyder, Academic Press, New York, 1969, p. 117.H. Matsukubo and 33. Kato, J.C.S. Chew. Comm., 1974, 675;J.C.S. Perkin I , 1975, 632; CJtem. Letters, 1975, 767; H. Matsu-kubo, 111. Kojima, and H. Ksto, ibid., p. 1153; K. T. Potts andJ. Baum, J.C.S. Chenz. C o m n . , 1973, 833; T. Eicher and V.Schafer, Tetrahedron, 1974, 30, 4025; H.-D. Martin and M.Hekman, Angew. Chew. Intenznt. Edn., 1972, 11, 926.should be compared with the reactions of (2) withnitrone~,~ nitrilimines,6 and nitrile oxides,' which giveadducts across both the cyclobutene and the cyclo-hexadiene double bonds. When the adducts (3a and b)were heated, fragmentation to phthalate (5) occurred inpreference to extrusion of SCO or PhNCO to give 1,6-diphenyl-7,9-dithiatricyclo[4.2.1 .O2y5]non-3-en-8-one (4a)(80%) and its 7-aza-analogue (Pb) (56%), respectively.The adducts (3a and b) were converted into thecorresponding S-oxides (6a) (92%) and (6b) (93%) withm-chloroperbenzoic acid (MCPBA) .We expected thatthese compounds would undergo fragmentation of themesoionic part, because of the reports that SO is morereadily extruded than SCO and PhNCO.*.* However,fragmentation to phthalate (5) still occurred to give thecorresponding tricyclic S-oxides (7a) (79%) and (7b)(70%), identical with the S-oxides prepared by oxidationof (4a and b) with MCPBA.The above results show that the triene (2) acts as amasked cyclobutadiene ; reactions of this type affordan attractive synthetic route to tricyclic systems suchas (4) and (7').Unsuccessful attempts to prepareheterocyclic systems analogous to (4) or its fragmentationproduct by the reaction of cyclobutadiene with amesoionic oxazolone have been reported by Rees andhis co-worker~.~ We expected that the tricyclic sul-phides (4) and sulphoxides (7) could be convertedfurther into the corresponding fully unsaturated seven-H. Matsukubo and 13. Kato, J.C.S. Chem. Conzm., 1976, 840.5 G. Bianchi, A. Gamba, and R. Gandolfi, Tetrahedron, 1972,6 G. Bianchi, R. Gandolfi, and P. Griinanger, Tetyahedron,7 G. Bianchi. R. Gandolfi, and P. Grunanger, Tetrahedron,8 H. Kato, S. Kakazawa, T. Kiyosawa, and K. Hirakawa,9 T. L. Gilchrist, E. E. Nunn, and C.W. Rees, J.C.S. Perkin I ,28, 1601.1973, 29, 2405.1970, 26, 5113.J.C.S. Perkin I , 1976, 672.1974, 12621976 2563or eight-membered heterocycles (8) or (9) by extrusionof XCO or SO with concomitant cleavage of the cyclo-butene ring. However, compounds (4) and (7) werethermally very stable, and we have not been able toisolate such products after heating or irradiation.The assignments of configurations t o structures (3),(4), (6), and (7) aIe not very conclusive. The smallcoupling constants (ca. 3 Hz) between the two pairs ofthe situation is reversed with the tricyclic sulphides(4a and b), both of which show a larger degree of mag-netic non-equivalence of the 3- and 4-protons (0.22 and0.47 p.p.m.) than of the 2- and 5-protons (0.12 and0.16 p.p.m.).The sulphides (4) should retain the sameconfiguration as the other products: it is unreasonableto expect inversion of configuration during fragment-ation of (3), and the possibility of valence isomerisationheat + C02Me‘C02MeMCPBA159Hheat 4 C02Me’K COzMePh0 9Ph(9 I(71 “cyclobutane protons (H-2 and -3 and H-8 and -9) in(3) and (6) suggest that the approach of (1) to (2)occurred from ‘ above ’ the surface of the cyclobutenering. That only the pair of protons a t the 3- and 8-positions of (3) and (6) show magnetic non-equivalenceto a considerable degree ( 0 . 2 9 4 . 5 1 p.p.rn.) suggeststhat the XCO group is exo to the cyclobutane ring.The small effect of the sulphoxide oxygen with respectto the chemical shift values of (6) may be taken asevidence that the sulphoxide oxygen is also exo t o thecyclobutane ring.The same consideration may beapplied regarding the configuration of (7). However,Ph\0Ph(10)4 ++ ( 5( 5 )Ivia the bridged diene (10) may be dismissed in view ofan unsuccessful attempt to trap (10) with dienophilesand, above all, because the same S-oxides are formedby fragmentation of (6) and by oxidation of (4) withMCPBA. A similar but smaller magnetic non-equiva-lence of the olefinic protons is also observed with thecorresponding S-oxides (0.14 and 0.11 p.p.m.), whereasprotons at the corresponding positions (H-2 and -9)of (3) and (6) are all magnetically equivalent. Thechange in the torsion angle H-C-C-H with respect tothe C-X-CO-C plane probably causes this anomalousresult2564 J.C.S.Perkin IEXPERIMENTALM.p.s were determined with a Yanagimoto hot-stageapparatus. U.V. and i.r. (KBr) spectra were recorded withHitachi EPS-3T and EPI-SII spectrophotometers, andn.m.r. (CDCl,; Me,Si internal standard) and mass (70 eV;direct insertion) spectra were measured with JEOLJNM-4H-100 (100 MHz) and Hitachi RMU-6 spectro-meters. All concentrations were carried o u t in vacuo, andcompounds stated t o be identical were so on the basis ofm.p., mixed m.p., and i.r. spectral determinations.Dimethyl 6-0xo-4,7-diphenyl-5,15-dithiapentacyclo-CS.2.2. 1.4~70.2~903~S]pentadeca-l 1,13-diene-ll,12-dicarboxylate(3a) .-A solution of the mesoionic 2,5-diphenyl- 1,3-dithiol-$-one ( l a ) lo (1 mmol) and dimethyl tricycl0[4.2.2.0~*~]deca-3,7,9-triene-7,8-dicarboxylate (2) (80% purity; 1 mmol)in benzene (20 cm3) was refluxed for 50 h.The precipitatewas collected and the solution was concentrated. Theresidue was triturated with methanol and the combinedprecipitate and residue were recrystallised (from benzene-n-hexane) t o give the adduct (3a) as prisms (97y0), m.p.198-200 "C (Found: C, 67.25; H, 4.55. C29H2,0 S,requires C, 67.4; H, 4.7y0), U.V. (MeOH) end absorption;vmx. 1 728sh, 1 714, and 1 280 cm-l; 6 7.52-7.20 (10 H, m,ArH), 6.69 (2 H, dd, J 3.0 and 3.9 Hz, =CH), 4.15 (2 H, m,H-1 and -lo), 3.67 (6 H, s, Me), 3.18 and 2.89 (each 1 H,dd, J 6.3 and 3 Hz, H-3 and -8), and 2.08 (2 H, m, H-2 and-9); irradiation at 6 6.67 caused the signal a t 6 4.15 t ocollapse t o d, J 3 Hz, and similarly irr.4.15 6.69, s;2.08- 3.16, d, and 2.89, d, J 6.3 Hz; wzle 456 (6%,M - COS), 236 (50), 163 (loo), 121 (34), and 77 (46).Dimethyl 6-0xo-4,6,7-triphenyl- 5-aza- 15-tlziaj~entacyc20-r8.2.2.1 . 4 9 70.2,903,8]pentadeca- 1 1,13-diene- 1 1,12-dicarboxyZate(3b) .-A solution of the mesoionic 2,3,5-triphenylthiazol-4-one (lb) 1 2 (4.4 mmol) and the triene (2) (4.4 mmol) inbenzene (150 cm3) was refluxed for 200 h. The solutionwas concentrated and the residue was chromatographed onsilica (chloroform) t o give the adduct (3b) as prisnzs (frombenzene-n-hexane) (43y0), m.p. 201-202 "C (Found:C, 72.9; H, 4.95; N, 2.35. C3,H,,N05S requires C, 73.0;H, 5.1; N, 2.45%), U.V.(MeOH) end absorption; v,,1723sh, 1714, and 1276 cm-l; 6 7.44-7.22 (10 H, m,ArH), 7.10-6.95 (3 H, m, ArH), 6.82-6.72 (4 H, m, ArHand =CH), 4.31 and 4.18 (each 1 H, m, H-1 and -lo), 3.72(6 H, s, Me), 3.17 and 2.85 (each 1 H, dd, J 6 and 2 Hz,H-3 and -8), and 2.34br (2 H, s, H-2 and -9); nz/e 381[4%, M - (5)], 262 (15), 180 (13), 163 (loo), 160 (13), and77 (36).1,6-Diphenyl-7,9-dithiatricyclo [4.2.1 .02*5]non-3-en-8-one(4a).-The adduct (3a) (0.97 mmol) in xylene (40 cm3) washeated under reflux for 92 h ; the solution was concen-trated and the residue was chromatographed on silica(benzene) t o give needles (from petroleum) of (4a) (SOYo),m.p. 145.5-146 "C (Found: C, 70.85; H, 4.25. C1,HI40S,requires C , 70.8; H, 4.4%), U.V.(MeOH) end absorption;vmx. 1 703 cm-1; 6 7.70-7.25 (10 H, m, ArH), 6.43 and6.21 (each 1 H, d, J 2.8 Hz, =CH), and 4.11 and 3.99 (each1 H, d, J 3.5, H-2 and -5); m/e 262 (66%; M - COS),236 (17), 229 (25), 173 (26), 160 (68), 121 (loo), and 77 (28).A later eluate afforded dimethyl phthalate (5) (120%;10 H. Gotthardt and B. Christl, Tetrahedvon Letters, 1968, 475;H. Gotthardt, M. C . Weisshuhn, and B. Christl, Chem. Ber., 1976,109, 740.W. G. Dauben and L. N. Reitman, J . Org. Chem., 1975, 40,835.crude), which was converted l3 into phthalic anhydride(35y0), identical with an authentic sample.1,6,7-Tri~henyl-7-aza-9-thiatricyclo[4.2.1. 0 2 p 5]non-3-en-8-one (4b).-A suspension of the addirct (3b) (0.26 mmol) ino-diethylbenzene (20 cm3) was heated under reflux for 11 h,and was similarly treated to give prisms (from n-hexane) of(4b) (56%), m.p.152-153 "C (Found: C, 78.75; H, 4.9;N, 3.55. C,,H,,NOS requires C, 78.7; H, 5.0; N, 3.650/,), a,, (PvIeOH) 245sh nm (log E 3.82); v,,, 1 699 cm-l;6 7.78-6.92 (15 H, m, ArH), 6.67 and 6.22 (each 1 H, d,J 3 Hz, =CH), and 4.18 and 4.02 (each 1 H, d, J 3.5 Hz,H-2 and -5); Yn/e 381 (28%, M ) , 262 (loo), 180 (88), 160(88), 121 (78), and 77 (92).Dithiolorzs Adduct S-Oxide (6a) .-A solution of the adduct(3s) (0.85 mmol) and Yn-chloroperbenzoic acid (MCPBA)(80% purity; 0.88 mmol) in dichloromethane (30 cm3) wasstirred a t room temperature for 7 h. The solution waswashed (aqueous sodium hydroxide ; water), dried(Na,SO,), and concentrated, and the residue was re-crystallised (from benzene-n-hexane) t o give prisms of(6a) (98%), m.p. 207-208 "C (Found: C, 64.9; H, 4.45.C29H2406S2 requires C, 65.4; H, 4.55%), Amas.(MeOH)217sh nm (log E 4.46); vmaK 1724~11, 1 714, 1 728, 1095,and 1066 cm-1; 6 7.67-7.25 (10 H, ni, ArH), 6.74 (2 H,t, J 3.8 Hz, =CH), 4.31 (2 H, ni, H-1 and -lo), 3.69 (6 H, s,Me), 3.14 and 2.63 (each 1 H, dd, J 8.5 and 3.5 Hz, H-3and -8), and 2.28br (2 H, s, H-2 and -9); m/e 290 [3%,(7a) - SO], 262 (lo), 230 (7), 194 (9), 173 (12), 163 (loo),160 (21), 121 (25), and 77 (30).Thiazolone Adduct S-Oxide (6b) .-A solution of the adduct(3b) (0.43 mmol) and MCPBA (0.44 mmol) in dichloro-methane (20 cm3) was stirred at room temperature for 6 h,and was worked up by a similar method to give (6b) (93%)as prisms (from chloroform-ether), m.p.195-196 "C(Found: C, 70.8; H, 4.8; N, 2.3. C,,H2,N0,S requiresC, 71.05; H, 4.95; N, 2.35%), A,,, (MeOH) 227 nm (log E4.44); v,,,. 1 723sh, 1 713, 1277, and 1066 cm-l; 6 7.75-6.95 (15 H, m, ArH), 6.83 (2 H, t , J 3 Hz, =CH), 4.45br(2 H, s, H-1 and -lo), 3.78 (6 H, s, Me), 3.13 and 2.72 (each1 H, J 9 and 3 Hz, H-3 and -8), and 2.46br (2 H, s, H-2and -9); m/e 397 [2%, (7b)], 349 (13), 219 (15), 194 (14).180 (18), 163 (loo), and 77 (45).1,6-Diphe~yl-7,9-dithiatricycZo[4.2.1 .02~5]non-3-e~z-8-one 9-Oxide (7a).-(a) A suspension of the S-oxide (6a) (0.23mmol) in xylene (15 cm3) was heated under reflux for 45 h.The solution was concentrated and the residue chromato-graphed on silica (benzene) t o give prisms (from chloro-form-ether) of (7a) (79%), m.p.171.5-174 "C (Found:C, 67.35; H, 4.0. C,,H,,O,S, requires C, 67.45; H,4.15%), U.V. (MeOH) end absorption; vmx. 1708 and1083 cm-1; 6 7.70-7.23 (10 H, m, ArH), 6.46 and 6.32(each 1 €1, d, J 3 Hz, =CH), and 4.51 and 4.06 (each 1 H,d, J 4 Hz, H-2 and - 5 ) ; m / a 338 (l%, M ) , 290 ( l l ) , 278 (9),262 (45), 1'73 (46), 160 (87), and 121 (100). A later fractionafforded dimethyl phthalate (crude; 1 looh), which wasconverted into phthalic anhydride ( goyo), identical with anauthentic specimen.(b) A solution of (4a) (0.06 nimol) and MCPBA (0.06mmol) in dichloromethane (2 cm3) was stirred for 5 h a troom temperature, washed (aqueous sodium hydroxide ;water), dried, and concentrated t o give prisms (from1 2 M.Ohta, H. Chosho, C. Shin, and K. Ichimura, NipponKagaku Zasshi, 1964, 85, 440.l3 J. G. Atkinson, D. E. Ayer, G. Buchi, and E. W. Robb, J .Amer. Chem. SOC., 1963, 85, 22571976 2565chloroform-ether) of (7a) (37%) , identical with the sampleprepared by procedure (a).1,6 , 7- Trip Jaenyl- 7-aza-9-thiatricyclo C4.2.1. 02*5]non- 3-en-8-one 9-Oxide (7b).-(a) A suspension of (6b) (0.52 mmol) inxylene (20 cm3) was refluxed for 22 h. The crystals of (7b)which separated were collected ; the solution was concen-trated and the residue was washed (ether) to afford (7b).Chromatography on silica (chloroform) of the ether wash-ings gave a further sample of (7b). The combined productwas recrystallised (chloroform-ether) to give p~isms of (7b)(total 700/,), m.p. 243-244 "C (decomp.) (Found: C, 75.2;H, 4.6; N, 3.45. C,,H,,NO,S requires C, 75.55; H, 4.8;N, 3.50/,), A,,, (MeOH) 226 nm (log E 4.36); vmx. 1714and 1069 cm-l; 6 7.78-6.95 (15 H, m, ArH), 6.48 and6.37 (each 1 H, d, J 2.6 Hz, =CH), and 4.57 and 4.13 (each1 H, d, J 4 Hz, H-2 and -5); m/e 397 (774, M ) , 349 (60),230 (40), 219 (95), 180 (loo), and 77 (85).(b) A solution of (4b) (0.13 mmol) and MCPBA (0.14mmol) in dichloromethane (5 cm3) was stirred for 3 h a troom temperature. Work-up similar to that in procedure(b) (above) gave prisms (chloroform-ether) of (7b) (67%),identical with the sample prepared by procedure (a).We are indebted to Kyorin Chemical Laboratories forelemental analyses and mass spectra, and to Rlr. NaomiTa kagi for experimental assistance .[6/1113 Received, 11th June, 1976
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