1,3-Dipolar character of six-membered aromatic rings. Part XXVII. Photochemically induced valence bond tautomerism and dimerisation of 3-oxido-1-phenylpyridinium

摘要

2338 J.C.S. Perkin II ,3-Dipolar Character of Six-membered Aromatic Rings. Part XXVII.Photochemically Induced Valence Bond Tautomerism and Dimerisation of3-Oxido-I -phenylpyridiniumBy Nicholas Dennis, Alan R. Katritzky.' and Horst Wilde, School of Chemical Sciences, University of EastAngiia, Norwich NR4 7TJIrradiation of the title compound (1 ) yields one of the photochemically allowed symmetrical dimers (I 6) togetherwith a bicyclic valence bond isomer (7) and two stereoisomers (1 8) and (20) of thermal addition products of (7) toa second molecule of the starting phenyl betaine. Analogues (1 9) and (21 ) of the dimers (1 8) and (20) were pre-pared by reaction of isolated (7) with the pyrimidine betaine (2). Irradiation of (1) in ally1 alcohol affords anaddition product (24) of (7).I-SUBSTITUTED 3-oxidopyridiniums, e.g.(1) and (2), positions with sin-electron addends2y3 The electro-, site,undergo thermal cycloadditions at the 2- and 6-positions regio-, and stereo-selectivity of these cycloadditions iswith 2x- and Gx-electron addends, and at the 2- and 4- rationalised by FMO t h e ~ r y . ~ We are now investigating1 Part XXVI, J. Banerji, N. Dennis, J. Frank, A. R. Katritzky, photochemically induced cycloadditions. Photodimer-and T. Matsuo, preceding paper.Part XX, N. Dennis, B. Ibrahim, and A. R. Katritzky, Part XXI, N. Dennis, B. Ibrahim, and A. R. Katritzky,J.C.S. Perkin I, 1976, 2296. J.C.S. Perkin I, 1976, 23071976 2339isation should give products of 2,4-2',4' or 2,6-2',6' four (A-D) were identified. Separation was achievedaddition ; there are four regio-possibilities (3)-(6), each by preparative thick-layer chromatography (C6H6-of which can take place in two stereo-senses.Prelimin-ary FMO calculations indicate that compounds of the Compound A was shown to be an isomer of (1) by masstype (3) or (4) should be formed preferentially. spectrometry (m/e 171) and elemental analysisEtOAc, 9 : 1) on silica gel.1H N.m.r. spectra (6 values) of cycloadducts aChemical shifts ( 6 )Proton(s)123456789101'2'3'5'NPhCH31 21,31 31,7 1,s1 , l O2,32,62,73cr, 3p3a, 43p, 43,43,54,65,66 79,lO8.97,sCoupling constants (Hz)(7)3.235.937.653.65 j6.88-7.26(7)1.53.86.01.41.8(16)3.194.35 g6.59 f4.63 63.194.35 g6.59 f4.636.70-7.30(16)3.31.56.01 .o7.66.03.37.6(18)4.472.40 f3.50 f3.26,3.16 f4.84,5.906.7-7.3 k6.7-7.3(18)0.01.50.07.1(19)5.083.50 f3.18 f3.10f5.34 f6.6-7.4 X-5.81 C6.372.236.6-7.4(19)0.01.50.08.0(20)4.65 f3.213.27 f3.113.67 la4.85 la6.7-7.35.936.7-7.3 1(20)9.11.50.07.9(24)2.09 f (342.90 f3.40 f4.03 65.00-6.10'6.00-6.10 16.60--T.30(24) "'4.018.00.05.03.7 3.7 3.70.09.7 10.0 9.94.8 4.5 4.30.0 0.0 6.2a In p.p.m.relative to internal Me,Si. In CDCl,. Doublet of doublets. Quintet. Singlet. f Doublet. Triplet,Quartet. Doublet of triplets. j Octet. Signal hidden in this region. 1 Complex.J1v,a* 6.0, J1p,3# 1.0 Hz.Irradiation of 3-oxido-l-phenylpyridinium (1) inethyl acetate with a 3 500 A lamp in a Kayonet reactor(RPQ-100) gave a mixture of five components of whichR11 1R: PhI21 R z L , 6 - dimet hylpyri mid in - 2 - y lR(31R @ R(4 100 0( 5 1 (61(C,,H,NO). The i.r. spectrum shows a v(C=O) at 1725cm-l characteristic of an @-unsaturated ketone in a five-membered ring (cf. cyclopent-2-enone * 1 710 cm-l).3The n.m.r. spectrum (Table) clearly demonstrates thestructure as that of 6-phenyl-6-azabicyclo3.1 .Ohex-3-en-2-one (7): the bridgehead proton, H-I, gives adouble doublet by cis-coupling with the other bridgeheadproton, H-5, and long-range four-bond coupling withC. J. Pouchert, ' The Aldrich Library of Infrared Spectra,'hldrich Chemical Co., Pitman, Bath, 1970, p.2032340 J.C.S. Perkin IH-3 (cj. long-range coupling of 2.1 Hz in the case of4,5-epoxy-3,4-diphenylcyclopent-2-enone 5) ; the vinylicH-3 signal is a double triplet (cis-vicinal coupling withH-4 and long-range four-bond coupling with H-1 and-5); the vinylic H-4 signal appears as a double doublet(cis-vicinal coupling with H-3 and small vicinal couplingwith H-5). All these assignments were confirmed bydouble resonance experiments ; irradiation at the fre-quency of H-5 (an octet) caused the signals of H-1, -3, and-4 to collapse to doublets. Irradiation a t the frequencyof H-3 caused the signals of H-4 and -1 to collapse to asinglet and a doublet, respectively, Finally irradiationa t the frequency of H-4 converted the double triplet oeuro;H-3 into a finely split doublet.The phot oisomer 6-phenyl-6-azabicyclo 3.1 .Ohex-3-en-2-one (7) is presumably formed from 3-osido-1-phenylpyridinium (1) by a photochemically alloweddisrotatory ring closure.Thermal conrotatory ringopening of the aziridine, 2,3-fused to a five-memberedring, to give the pyridine valence isomer ( l ) , is notformally allowed. Hence, despite the strained structure,the photoisomer (7) is stable in the crystalline form.Isomerism between 3-oxidopyridinium and 6-azabicyclo-3.1.0hex-3-en-2-one has been postulated to explainthe relatively high volatility of the 3-oxidopyridinium inthe mass spectrometer.' In the isoquinolinium series,Hansen and Undheim reported the reversible photo-chemically allowed valence isomerism between l-aryl-la,6a-dihydroindeno 1,2-bazirin-6( 1H)-ones (8) and2-aryl-4-oxidoisoquinoliniurn (9).Again, Lown andMatsumoto have shown that l-cyclohexyl-6-(cyclo-hexylimino) - 1 a, 6a-dih ydro-l a-phenylindeno l ,241 azi-ridine (10) undergoes photochemical valence tauto-merisation to the isoquinolinium imide (11). In therelated isoelectronic 3-oxidopyrylium series, the tri-phenyl derivative (12) is converted into the photoisomer,not isolated but suggested to have structure (14).loIn the analogous tetraphenyl series, (15) is the stableform and is converted into (13) on irradiation; (13) wasisolated as the perchlor ate. l1Compound B, m.p.175-176 O C , was shown to be adimer of the betaine (1) by mass spectrometry (m/e 342)and elemental analysis (C,,H,,N,O,). The i.r. spectrumhad a v(C=O) band at 1744 cm-l characteristic of asaturated ketone. The n.m.r. spectrum (Table) clearlyestablished the structure as that of (lSR,2RS,6RS,-7SR) -3,S-dipheny1-3,8-diazatricyclo 5.3.1. 12' 6 dodeca-4,9-diene-ll,12-dione (1 6). The pair of bridgeheadprotons H-1 and -6 give rise to a quintet (coupling withH-2 and -7, and H-10 and -6, and long-range W-typecoupling with H-7 and -2). The second pair of bridge-head protons, H-2 and -7, give a triplet (coupling with6 A. Padwa, Tetrahedron Letters, 1964, 513.6 T. L. Gilchrist and R. C. Storr, Organic Reactions andOrbital Symmetry,' Cambridge University Press, 1972, p.58;R. Huisgen and H. Maider, Angew. Chem. Internat. Edn., 1969, 8,604.7 T. Grernneberg and K. Undheim, Acta Chem. Scand., 1971,25, 2507; K. Undheim and T. Hurum, ibid., 1972, 26, 2355.P. E. Hansen and K. Undheim, J.C.S. Perkigz I , 1975, 305.H-1 and -6 and long-range W-type coupling with H-6and -1). The vinylic pair H-5 and -10 give a quartet(cis-vicinal coupling with H-4 and -9 and vicinal couplingwith bridgehead protons H-6 and -1). The olefinic pairH-4 and -9 give a doublet by cis-coupling with H-5 and-10. These assignments were supported by spin-spindecoupling experiments. Irradiation at the H-1 and-6 frequency caused the signal of H-2 and -7 to collapseto a singlet and that of H-10 and -5 to collapse to adoublet.Irradiation at the frequency of the H-2 and-7 signal caused the signals of H-1 and -6 to collapse to adoublet. Again irradiation at the frequency of theolefinic protons H-5 and -10 produced a doublet fromH-6 and -1 and a singlet from H-4 and -9. Finally,irradiation at the frequency of the olefinic protons H-4and -9 caused the signals of H-5 and -10 to collapse to adoublet. The exo-stereochemistry is clearly defined by mNR 0(8 I'- "L6Hll(1010-(91Ph1 1 4 ) R = HIt5IR:Phthe small coupling constant ( J 3.3 Hz) between euro;3-1and -2 and H-6 and -7 (the dihedral angle of ca. 50"corresponds12 to a calculated J of ca. 3 Hz). Thedimer (16) can be crystallised from chloroform, butin solution it decomposes within a few hours at20 "C.It is presumably formed by a photochemicallyallowed 6 +- 6n 1,3-dipolar cycloaddition between twomolecules of the betaine (1). Tropone also gives a6 -1- 61 dimer (17) on irradiation by a photochemicallyallowed ,6, 4- ,6J cyc10addition.l~Compound (C), m.p. 221-222 O C , was shown by massspectrometry (mle 342) and elemental analysis (C2,HI8-N,O,) to be another dimer of (1). The i.r. spectrumshows v(C=O) at 1 740 cm-1, characteristic l4 of a satur-J. W. Lown and K. Matsumoto, Chem. Counm., 1970, 692;Canad. J . Chem., 1971, 49, 3443.lo E. I?. Ullman, J . Amer. Chem. SOL, 1963, 85, 3529.l1 J. M. Dunston and P. Yates, Tetrahedron Letters. 1964, 505.l2 S. Sternhell, Quart. Rev., 1969, 23, 236.l3 T. Mukai, T. Tezuka. and Y .Akasaki, J . Anzer. Chem. Soc.,1966, $8, 5025.l4 J. R. Dver, ' Applications of -4bsorption Spectroscopy ofOrganic Compounds,' Prentice-Hall, Englewood Cliffs, NewJersey, 1965, p. 341976ated ketone in a five-membered ring, and at 1 685 cn-l,characteristic l5 of an ap-unsaturated ketone in a bicyclo-3.2. lloctenone system. The n.m.r. spectrum (Table)n0( 1 7 )demonstrates the substance to be (lRS,2RS,SRS,-5 SR, 7SR, 8RS) -4,12-diphenyl-4,12-diazatetracyclo-6.3.1.02~7.03~5dodec-9-ene-6,11-dione (18). The signalsfor the vinylic protons H-9 and -10 form a characteristicpattern observed in N-phenyl l5 cycloadducts: H-9 givesa quartet (cis-vicinal coupling with H-10 and couplingwith the bridgehead proton H-8), and the H-10 signal isa doublet (coupling with H-9) further split by W-typelong-range coupling with the bridgehead H-1.Thesignals for the bridgehead protons H-1 and -8 appear as asinglet (with fine structure due to long-range couplingwith H-10) and a doublet (coupling with H-9), respect-ively. The signals for H-2 and -7 form a typical ABquartet due to cis-vicinal coupling. The lack of appre-ciable coupling between H-7 and -8 and betweenH-1 and -2 establishes the exo-configuration about the2,7-bridge. The signals for the bridgehead protons H-3and -5 also form a typical AB quartet due to cis-vicinalcoupling. Again the lack of appreciable couplingbetween H-2 and -3 establishes the endo-configuration(relative to the 1,s-bridge) for the aziridine ring. Theseassignments were confirmed by double resonance :irradiation at the frequency of H-9 simplified the signalsof H-8 and -10 to singlets.Irradiation at that ofH-3 caused the signal of H-5 to collapse to a singlet, andirradiation at that of H-2 caused the signal of H-7 tocollapse to a singlet. The dimer (18) is stable in crystal-line form but not in solution.Compound (D), m.p. 218-219 "C, had a mass spectrum(nz/e 312) identical with that of compound (C) and anelemental analysis consistent with the formula C,,H,,-N,O,. The i.r. spectrum had v(C=O) bands at 1735crn-l, characteristic of a saturated ketone in a five-membered ring, and 1680 crn-l, Characteristic of anap-unsaturated ketone. The n.m.r. spectrum (Table)demonstrates the compound to be (lRS,2SR,3SR,-5RS, 7RS, 8RS) -4,12-diphenyl-4,12-diazat etracyclo-6.3.1.02~7.03~5dode~-9-ene-6,11-dione (20).Again thesignals of the vinylic protons H-9 and -10 form thecharacteristic pat tern observed in N-phenyl cyclo-adducts,15 k.e. a quartet (coupling with H-8 and -10)and a double doublet (coupling with H-9 and -l)?respectively. The signals of the bridgehead protonsH-8 and -1 appear as a quartet (coupling with both H-7and -9) and a doublet (coupling with H-2, with finestructure due to long-range W-type coupling with H-lo),respectively. The signals for H-7 and -2 can be analysedas a pair of quartets on a first-order basis. The appreci-able coupling between H-1 and -2 and between H-8and -7 establishes the endo-configuration about the2,7-bridge. Again the signals for the bridgehead protonsH-3 and -5 form a typical AB quartet due to cis-vicinalcoupling.The lack of appreciable coupling betweenH-2 and -3 establishes the exo-configuration (relative tothe 1,8-bridge) for the aziridine ring. These assign-ments were confirmed by double resonance. Irradiationat the frequency of H-1 caused the broad doublet ofH-10 to sharpen, and irradiation at that of H-10 causedthe broad doublet of H-1 to sharpen. Irradiation at thefrequency of H-9 caused the H-10 and -8 signals tocollapse to a broad singlet and a do,ublet, respectively.Irradiation at that of the bridgehead H-8 caused theH-7 signal to collapse to a doublet, and irradiation atthat of the bridgehead H-7 caused the quartet of H-8 toR'(181 R' :R2=Ph(191 R1= P h , R2=4, 6 - dimethylpyrimidin- 2-$11201 R ' = R2: Ph121 I R':Ph,RL=L,6-dime l h y l p y r icollapse to a doublet.Finally irradiation at the fre-quency of H-2 caused the H-1 signal to collapse to abroad singlet.6-Phenyl-6-azabicyclo3.1 .O hex-3-en-2-one (7), actingas a 2x-electron component, reacted with 1-(4,6-dirnethyl-pyrimidin-2-yl) -3-oxidopyridinium (2), generated fromthe dimeric mixture (22) m (23), to give a mixture ofl5 N. Dennis, A. R. Katritzlry, T. Iliatsuo, S. K. Parton, andbsol;*. Takeuchi, J.C.S. Perkin I, 1974, 7462342 J.C.S. Perkin Itwo stereoisomeric cycloadducts. The cycloadduct ofm.p. 268-269 "C had an elemental analysis consistentwith the formula C,,H,N,O, and its mass spectrumshowed m/e 372.The i.r. spectrum showed v(C=O)bands at 1 742 cm-l, characteristic of a saturated ketonein a five-membered ring, and 1695 cm-l, characteristicof an +unsaturated ketone. The U.V. spectrum hasA,, 235 nm, characteristic of an @-unsaturated ketonedoublet cis-coupling with H-3p; J4,3a 0 Hz since thedihedral angle H(4)CCH(3a) = 90'1. The methyleneproton H-3a gives a doublet (geminal J3Q,3p 18 Hz, cf.cyclopentanone, Jgem 16 - 19.0 to -19.5 Hz) and themethylene proton H-3P gives a double doublet by furthercoupling to H-4 (5 Hz). The propenyloxy-group istrans to the aziridine ring since the signals of both H-4and -5 are doublets. The olefinic proton signals formMeNMe(221in an azabicyclo3.2. lloctenone system.15 The n.m.r.spectrum (Table) confirmed the identification as (lRS,-2RS, 3RS, 5SR ,7SR,8RS) - 12- (4,6-dimethylpyrimidin-Z-yl) -4-phenyl-4,12-diazat etracyclo 6.3.1 .02j 7.033 5 dodec-9 -ene-6,1 l-dione (19).A second cycloadduct, m.p.260-261 O C , C,,H,,N,O,(elemental analysis and m/e 372), v(C=O) 1 740 and 1 695cm-l, h,,, 235 nni, proved to be (lRS,2SR,3SR,5RS,-7RS ,8RS) - 12- (4,B-dime thylpyrimidin-2-yl) -4-phenyl-4,12-diazatetracyclo6.3.1 . 0 2 p ' . 0 3 3 5 dodec-9-ene-6,ll-dione (21).The stereoisomeric pairs (18) and (20), and (19) and (21)are formed by thermally allowed 4 + 2)t 1,3-dipolarcycloadditions of the valence bond tautomer (7), actingas a 2x-electron component, with the betaines (1) and(a), respectively.H ( 2 4 1Irradiation of 3-oxido-l-phenylpyridinium in allylalcohol yielded a single major product (20) smallquantities of compounds (7), (16), (18), and (20) could bedetected by t.l.c.1, C,,H,,NO, (analysis and m / e 229).The i.r.spectrum had a v(C=O) band a t 1745 cm-l,characteristic of a saturated ketone in a five-memberedring. The n.m.r. spectrum (Table) showed the com-pound to be (lSR,4RS,5RS)-6-pheny1-4-(prop-2-enyl-oxy) -6-azabicyclo3.1 .O hexan-2-one (24). The signalsfor the bridgehead protons, H-1 and -5, form an ABquartet ( l e i s 4 Hz). The methine proton H-4 gives al6 R. C. Cookson, T. -4. Crabb, J. J. FrankeI, and J. Hudec,Tetrahedron, Suppl. 7, p. 383.' 01231a complex ABX multiplet. The double doublet at 64.03 is due to the methyleneoxy-group (H-1') coupled tothe adjacent vinyl a-proton by 6 Hz (cf.4-10 Hz forsimilar systems17) and to the trans-p-vinyl proton by 1Hz (cf. 0.5-2 Hz for similar systems 17). The aziridine(24) was presumably formed by Michael addition of theallyl alcohol to the initially formed photoisomer, 6-pheny1-6-azabicyclo3.1 .Ohex-3-en-2-one (7). Preferen-tial addition of the alcohol to the least hindered face ofthe photoisomer (the face trans to the aziridine ring)accounts for the observed stereochemistry.EXPERIMENTALM.p.s. were determined with a Reichert apparatus.Spectra were recorded with the following instruments : i.r.Perkin-Elmer 257 ; mass, Hitachi-Perlrin-Elmer RMU-6E ;U.V. Unicam SP 800A; n.m.r., Varian Hh-100.Com-pounds were purified until they were observed as singlespots on t.1.c. silica gel (PF 254) ; benzenc-EtOAc (9 : l)Irradiations with an external light source were performedwith a Rayonet reactor (RPQ-loo), with 3 500 A lamps, inquartz flasks.For irradiation with an internal light source a medium-pressure mercury arc, type Hanovia I'CIC IL, and water-cooled Pyrex containers were used. All irradiations wereperformed at 26-35 "C.Preparative layer chromatography was performed onsilica gel (Merck PF 254). The plates bsol;rere developed withbenzene-EtO14c (9 : 1). The fractions mere scraped off theplates and isolated by extraction with EtOAc.Iwadiation of 3-Oxido- l-pJaenylpy~idinium (1) .-(a) InEtOH-EtOAc. 3-Oxido-l-phenylpyridinium (3.4 g, 0.02mol) in absolute EtOH (30 nil) and EtOAc (350 ml) wasirradiated with an external light source for 20 h.The redsolution was evaporated to dryness at 30 "C and 10 mmHg,and the residue separated by thick-layer chromatography.6-PhenyZ-6-nzabicycZo3.1.0lzex-3-en-2-one (7) (180 mg, 6 ;RF 0.33) crystallised from EtOH-H,O as yellow needles,m.p. 78-79 "C (Found: C, 76.7; H, 5.4; K. 8.3. C1,H,NOl7 L. M. Jackman, ' Applications of Nuclear Magnetic Reson-ance Spectroscopy in Organic Chemistry,' eds. D. H. R. Bartonand W. Doering, Pergainon, Oxford, 1959, p. 851976requires C, 77.2; H, 5.3; N, 8.2); vmx. (Kujol) 1725(ap-unsat. ketone G O ) and 1 600 cm-l (benzene C=C);A,,, (EtOH) 229 nni (log E 4.00) ; m/e 171.( 1SR,2RS,6RS,7SR)-3,8-Diphenyl-3,8-diazatricyclo-5.3.1.12~6dodeca-4,9-diene-11,12-dione (16) (1 g, 29; RF0.60) was isolated as pale yellow needles, m.p.175-176 "C(decomp.) (from CHCl,) (Found: C, 76.8; H, 5.3; N, 8.1.C,,H,,N,O, requires C, 77.2; H, 5.3; N, 8.2); vmx(Nujol) 1744 (sat. ketone GO), 1632 (enamine C=C),1 600 and 1500 cm-l (benzene C X ) ; Lx. (EtOH) 222(log E 4.35), 268 (4.35), and 341 nm (3.86); m/e 342. (lRS,-ZRS, 3RS, 5SR,7SR,8RS)-4,12-DiPhenyl-d, 1 2-diazatetra-cyclo6.3. 1.02*7.03~5dode~-9-ene-6,11-dione (18) (95 mg, 3 ;Rp 0.44) was isolated as yellow needles, m.p. 221-222 "C(from EtOH) (Found: C, 77.0; H, 5.4; N, 7.9); vmax.(CDC1,) 1740 (sat. ketone G O ) , 1685 (ap-unsat. ketoneGO), 1600, and 1 500 ern-1 (benzene C=C); Amxa (EtOH)236 nm (log E 4.35); m/e 342.(1RSJ2SR,3SR,5RS,7RS,-8RS)-4,12-Diphenyl-4, 12-diaxatetracyclo6. 3.1 . 0 2 g 7.03* "3-dodec-9-ene-6,ll-dione (20) (30 mg, 1; R p 0.22) crystal-lised as yellow needles, m.p. 218-219 "C (EtOH) (Found:C, 76.7; H, 5.3; N, 7.9); vmx. (CDC1,) 1735 (sat. ketoneGO), 1 680 (ap-unsat ketone, GO), 1 600, and 1 500 cm-l(btmzene G C ) ; A,,,. (EtOH) 236 nm (log E 4.33); in/e 342.3-Oxido- 1-phenylpyridinium (2.8 g,0.016 mol) in ally1 alcohol (80 ml) was irradiated with aninternal light source for 30 h. The red solution wasevaporated to dryness at 80 OC and 10 mmHg and the redoily residne purified by preparative thick-layer chromato-graphy. ( 1 SR,4R.S, 5RS) -6-Yhenyl-4- (prop-2-enyZoxy) -6-aza-bicYcZoi3.1.0hexan-2-one (24) (0.7 g, 20; RF 0.44) wasisolated as a yellow unstable oil (Found: C , 73.6; H, 6.8;N, 6.8.C14H15N02 requires C, 73.3; H, 6.6; X, 6.1);(b) I n ally1 ulcohol.2343vmx. (CDC1,) 1 745 (sat. ketone GO), 1 600, and 1 500 cm-l(benzene, C=C) ; m/e 229.Reaction of 6-Phenyl-6-azabicyclo3.1.Ohex-3-en-2-one (7)with the Mixture of 3,l l-Bis-(4,6-dimethyZpyrimidin-2-yl)-3,1l-diazatricyclo5.3.1.12~~dodeca-4,9-diene-8,12-dione (22)and 3,l l-Bis-(4,6-dirnethylpyrimidin-2-y1)-3,1 l-diazatri-cycZ05.3.1. 12~6dodeca-4,8-diene-10, 12-dime (23) .-Com-pound (7) (100 mg, 0.G x mol) and the betaine dimermixture (120 mg, 0.3 x lo-, mol) in dry MeCN (30 ml)were stirred a t room temp. for 100 h. The solvent wasremoved at 60 "C and 10 mmHg and the solid residueseparated by thick-layer chromatography. (lRS,ZRS,-3RS,5SR, 7SR,8RS)-12-(4, 6-Dimethylp-yrimidin-2-yl)-4-phenyl-4,12-diazatetracyclo6. 3.1. 02* 7. 03j 5dodec-9-ene-6, 1 1-dione (19) (60 mg, 27) was isolated as pale yellow needles,n1.p. 268-269 "C (from EtOH) (Found: C, 71.1; euro;3, 5.8;N, 14.5. C22H20X402 requires C, 71.0; H, 5.4; N, 15.0);vmrtx. (CDC1,) 1742 (sat. ketone G O ) , 1695 (up-unsat.ketone GO), 1 595, and 1495 cm-l (benzene G C ) ; LaK(EtOH) 235 nm (log E 4.41); m/e 372. (lRS,2SR,3SR,-5RS,7RS,8RS)-12-(4,6-Dinzethylpyrimidin-2-yl)-4-phenyl-4,12-diazatetracyclo6.3.1. 02y7. 03*5dodec-9-ene-6,1 l-dione (2 1)(15 mg, 7) crystallised as yellow needles, 1n.p. 260-261 "C (EtOH) (Found: C, 71.2; H, 5.3; N, 14.6);vmL (CDCl,) 1740 (sat. ketone GO), 1695 (ap-unsat.ketone G O ) , 1 595 and 1 500 cm-l (benzene C=C) ; A,,,(EtOH) 235 nm (log E 4.44); nz/e 372.We thank the Karl Marx University, Leipzig, for leave ofabsence (to H. W.), and Dr. A. D. McNaught (ChemicalSociety) for help with nomenclature.6/020 Received, 5th January, 1976