Heterodiene syntheses. Part XVI. A new 4 + 2 cycloaddition pathway in the reaction of 2-oxoindolin-3-ylideneacetophenones with ethyl vinyl ether

摘要

1248 J.C.S. Perkin IHeterodiene Syntheses. Part XV1.l A New 4 + 21 Cycloaddition Path-way in the Reaction of 2-Oxoindolin-3-ylideneacetophenones with EthylVinyl EtherBy Gianfranco Tacconi," Andreina Corsico Piccolini, Pier Paolo Righetti, Enrico Selva, and GiovanniDesimoni, lstituto di Chimica Organica dell'Universit8, 271 00 Pavia, ItalyIn addition to dihydropyran(2) and (3) and dihydrofuran (4) derivatives, the reaction of (1 -acetyl-2-oxo-indolin-3-y1idene)acetophenones with ethyl vinyl ether gives 1 -acetyl-3-aroyl-5-ethoxy-Za,3,4,5-tetrahydro-benzcdindol-Z(l H ) -ones. Their formation is rationalized in terms of a Diels-Alder reaction between the vinylether and the styrenic diene system of the oxoindolylidene derivatives, followed by a hydrogen shift and re-aromatization.The configuration and conformation of the new adducts were determined by n.m.r. spectroscopyand confirmed by X-ray analysis.WE have previously described the reaction of (E)-2-oxo- RESULTS AND DISCUSSIONindolin-3-ylideneacetophenones (1) with ethyl vinyl The elemental analysis of the colourless by-product isether to give cis- and trans-2,3-dihydropyrano2,3-b consistent with a 1 : 1 adduct, and the i.r. spectrum stillindoles (2) and (3) via a 4 + 21 heterodiene cyclo- has three carbonyl bands, with the ketonic absorptionaddition, and 3-(2-oxoindolin-3-yl)dihydrofurans (4), shifted to higher wave number owing to removal ofwhose formation involves a zwitterionic intermediate conjugation (see Experimental section). If the exocyclic(Scheme 1).When the N-substituent is an acyl group C=C group is involved in the reaction, at first glance aOyArSCHEME 1131I41all the aroyl substrates (1; Ar = Ph, fi-MeO*C,H,, orP-NO,*C,H,) gave a low yield of a fourth product; wereport here the elucidation of its structure, which helps toclarify the complex mechanism of heterodiene reactionsand indicates their synthetic possibilities.1 Part XV, G. Desimoni, M. Monticelli, M. Nicola, and G.2 G. Tacconi, P. Iadarola, F. Marinone, P. P. Righetti, and G.Tacconi, J . Amer. Chem. SOL, in the press.Desimoni, Tetrahedron, 1975, 31, 11 79.2 + 21 cycloaddition to give a spirocyclobutane deriva-tive or a Michael reaction seem the most reasonablepathways since such behaviour has already been foundin enamine reactions.3However, the n.m.r.spectra (Table 8) showed the lossof an aromatic proton from the indoline system. De-coupling experiments (Figure 1) showed the presence ofG. Tacconi, A. Gamba, F. Marinone, and G. Desimoni,Tetrahedron, 1971, 27, 5611976 1249the sequence CH*CH,*CH*CH. Therefore, a tricyclicstructure, formed by a reaction involving both theexocyclic double bond and the 4-position of the indolineis proposed, with the formation of a new type of adduct:a l-acetyl-3-aroyl-5-ethoxy-2a,3,4,5-tetrahydrobenzcd-indole (5).the same zwitterionic intermediate already proposed forthe formation of (4)? the positive end of which couldperform an electrophilic intramolecular attack at the 4-position of the indoline route (b).If pathway (b) werefollowed, the electrophilic attack would be favoured byan electron-donating group in position 5, whereas anI Yd irr.Hc, Hcl 19 8 7 6 5 4 3 2 1 0SFIGURE 1 N.m.r. spectrum of the adduct (6a)The question arises as to whether the formation of (6)occurs via a Diels-Alder reaction between the vinyl etherRAc Ac(51a; R = X : Hb ; R:OMe,X:HC ; R-NO,, X:Hd; R=H,X=OMee; R=H,X=NO,(61a;X = OMeb; X : NO2and the styrene-like fragment, followed by hydrogentransfer and rearomatization Scheme 2, route (a) or viaP. Bamfield, A. W. Jonson, and A. F. Katner, J . Chem. SOC.J. Sauer, Angew. Chem. Internat. Edn., 1967, 6, 16.J. Sauer, Angew. Chem. Internat. Edn., 1966, 5, 211.(C), 1966, 1028.electron-attracting group should disfavour the reaction.Therefore, the reactions of I-acetyld-methoxy- and 1-acetyl-5-nitro-2-oxoindolin-3-ylideneacetophenones (6aand b) with ethyl vinyl ether were studied.Both substrates gave comparable amounts of the tri-cyclic adducts (5d and e) as well as the methoxy-ana-logues of (2)-(4) or the nitro-analogues of (2) and (3),respectively.Since substituents with opposite elec-tronic characters thus show no effect on the formationof the new adduct, a Diels-Alder pathway Scheme 2,route (a) is proposed. This reaction mode can becompared with that already found for 2-oxoindolin-3-ylideneacetone and acetylenecarboxylate~.~ If the latterexample can be regarded simply as a ' direct ' Diels-Alder reaction between an aromatic diene and acetyl-enecarboxylates, which probably act as acceptors,' thereaction mode reported here is unusual, since vinyl ethersusually behave as donors with +unsaturated carbonylderivatives .a7 (a) R.Sustmann, Tetyahedron Letters, 1971, 2721; ( b ) R.Sustmann and H. Trill, Angew. Chem. Internat. Edn., 1972, 11,838; (c) K. N. Houk, J . Amer. Chem. SOC., 1973, 95,4092.8 G. Desimoni and G. Tacconi, Chem. Rev., 1975, 75, 6511250 J.C.S. Perltin IThe n.m.r. spectra of the adducts (5) were analysed indetail. The C-2a proton signal appeared as a doubletwith a large 2a,3-axial-axial coupling; the aroyl sub-stituent must therefore be in the equatorial position (seeFigure 1). The C-5 proton showed two almost equaland small equatorial-equatorial and equatorial-axialDiels-Alder cycloaddition, since an endo-approach isrequired (Scheme 2) on account of the (E)-configurationof the starting material ( 1 ) .3 y 9 The following step is arearrangement, driven by the aromaticity gain, of theadduct formed first through a 1,3 suprafacial hydrogenshift ; this mode of reaction gives the configurationXor ( 6 ) 'OEtAcSCHEME 21OEt- x 2 T A r //NIA C 1 tt.31 Hs h i f tOEtA CTABLE 1Bond Iengths (A; e.s.d. less than 0.005 A) and bond angles ('; e.s.d. less than 0.5'): figures involving hydrogen atomsare not listedDistances Angles1.4261.4331.3901.5161.2021.5151.4861.5421.5201.5371.5081.4321.4051.3591.3811.370C( 7)-c (8)c ( 9)-c ( 1 0)C( 1O)-C( 11)C( 1l)-C( 12)C(8)-C(Sa)C(Sa)-C(Sb)C(9)-0 (25)C( 1 0)-C (1 5)C( 12)-C( 13)C (1 3)-C (1 4)C( 14)-C(15)C( 16)-0 ( 17)C ( 16)-C( 18)0 (22)-C( 23)C (23)-C( 24)0 (20)-c (2 1)1.3861.3791.3851.4921.2101.3731.3981.4161.3651.3201.4061.2111.4911.4151.4231.492couplings with the C-4 protons, the latter axial one alsobeing coupled (axial-axial) with the C-3 proton.There-fore the 5-ethoxy-group is axial and trans to the aroylsubstituent .The preferred conformation of the cyclohexene ring (c)is thus represented as in (7). The trans-OEt,COArconfiguration allows us to infer the transition state of thek(2)-N(l)-C(amp;)C (2)-N ( 1 )-C (1 6)C( 8a)-N (1)-C( 16)N( 1)-C( 2)( 2a)N( l)-C(2)-0 (1 9)C( 2a)-C( 2)-O( 19)C( 2)-C( 2a)-C( 3)C( 2)-C( 2a)-C( 8b)C(3)-C(2a)-C(Sb)C(2a)-C( 3)-C(4)C(2a)-C(3)-C( 9)C(4)-C(5)-C(aa)C(4)-C(5)-0(22)C( 5a)-C(5)-0 (22)C(5)-C(5a)-C(6)C(5)-C(5a)-C( 8b)C(6)-C(5a)-C(Sb)C (5a)-C( 6)-C( 7)C (5a)-C (6)-0 (20)C( 7)-C( 6)-O( 20)C (6)-C (7)-C( 8)C( 7)-C( 8)-C( 8a)C(4)-C(3)-C(9)C(3)-C(4)-C(S)109.1126.3124.5106.5125.9127.6121.7103.3109.5105.8113.5107.5113.1112.7108.3106.7123.8118.9117.0120.5113.5126.0121.0118.5N ( 1 )-C( 8a) -C( 8)N ( 1 )-C ( 8a) -C (8b)C (8)-C (8a) -C( 8b)C (2a) -C (8b) -C (5a)C(2a)-C(Sb)-C(8a)C (5a)-C (8b)-C ( 8a)C( 3)-C( 9)-0 (25)C ( 10) -C (9) -0 (25)C( 3)-c (9)-C( 10)C(9)-C(lO)-C( 11)C( 9)-C( 1 0)-C( 15) c ( 1 1 )-c ( 1 0)-c ( 1 5)C( 1O)-C( 1 1 )-C( 12) c ( 1 1 )-C( 12)-c ( 1 3) c ( 12)-C( 13)-C( 14)C( 13)-C( 14)-C( 15)C ( 1 O)-C (1 5)-C( 14)N ( l)-C( 16)-0 ( 17)N( l)-C( 16)-C( 18)0 ( 1 7) -C( 1 6)-C( 1 8)C(6)-0(20)-C(21)C(5)-0(22)-C(23)0(22)-C(23)-C(24)131.0109.1119.5126.7109.7123.1118.0121.4120.5124.4118.2117.3120.9119.5120.9120.8120.5119.8118.3121.9119.0113.3109.5actually found in (5).However, a 1,5 shift followedby keto-enol tautomerization or anionic proton loss andgain cannot a Priori be excluded, but it seems unlikelythat a single isomer would be obtained.Because of the importance of the configuration of thetricyclic adduct in defining the mechanism, the deduc-* R.L. Autrey and F. C. Tahk, Tetrahedron, 1967, 23, 9011976 1251tions from n.m.r. data were confirmed by an X-rayanalysis of the methoxy-derivative (5d) (Figure 2).HH amp; y O A r OEtCOAr rCrystal Structure.*-The crystal structure refinementThe yielded a final conventional R factor of 3.6.TABLE 2Torsion angles (") ; only the most significant are reported;e.s.d. range 0.3-0.7"; A and c denote the internaltorsion angles of the corresponding rings; B denotestorsion angles involving relationships between ring Band A and/or cAAACACcCcBCBA BBBC(8a)-N( l)-C(2)-C(2alC( 8a)-N ( 1)-C(2)-0 ( 19)C( 16)-N(l)-C(2)-C( 2a)C( 16)-N( I)-euro;( 2)-0 (19)C( 2)-N (l)-C( 8a)-C( 8)C (2)-N ( 1)-C (8a)-C (8b)C( 16)-N(l)-C(8a)-C(S)C ( 16)-N (1 )-C( 8a)-C (8b)C (2)-N( 1)-C( 16)-0 (1 7)C (2) -N ( 1)-C( 1 6)-C ( 1 8)C (8a)-N (1)-C ( 1 6)-0 ( 1 7)C ( 8a)-N ( 1) -C( 1 6)-C ( 1 8)N ( 1 )-C( 2)-C( 2a)-C( 3)N( 1)-C( 2)-C (2a)-C( 8b)0 ( 19)-C (2)-C( 2a)-C ( 3)0 ( 1 9)-C (2) -C (2a)-C( 8b)C( 2)-C(2a)-C(3)-C(4)C( 2)-C (2a)-C( 3)-C( 9)C (8b)-C( 2a)-C (3)-C (4)C( 8b)-C( 2a)-C(3)-C(9)C(2)-C(2a)-C(Sb)-C(5a)C( 2)-C (2a)-C(Sb)-C (8a)C(3)-C(2a)-C(Sb)-C(5a)C( 3)-C(2a)-C( Sb)-C(Sa)C (2a)-C( 3) -C (4) -C (5) c (9)-C( 3)-C(4)-C (5)C(?a)-C( 3)-C(9)-C( 10)C (2a) -C (3) -C ( 9) -0 (2 5) c (4) -c (3)-c (9)-c (1 0)C(4)-C (3)-C( 9)-0 (25)C (3)-C (4)-C( 5)-C(5a) c (3)-c (4) (5) -c ( 2 2 )C( 4)-C (5)-C (5a) -C (6)C ( 4)-C (5)-C( 5a) -C (8 b)0 (22)-C (5)-C( 5a) -C (6)0 (2 2)-C (5)-C (5a)-C (8b)C ( 5 a) -C (5) -0 (2 2) -C (2 3)C(5)-C(5a)-C(6)-C(7)C (5)-C (5a)-C(6) -0 (20)C (5)-C (5a)-C( 8b)-C(2a)C (5) -C (5a)-C (8b)-C (8a)C( 5a)-C(6)-0(20)-C(2 1)C (7)-C( 6)-0 (20)-C(2 1)pu'( 1 )-C (8a) -C (8b)-C (2a)K(l)-C(Sa)-C(Sb)-C(5a)C (8)-C (8a)-C (8b)-C (2a)c (4)-c (5) -0 (22)-c (23)c (3)-c (9)-C ( 1 0)-C( 1 1)C( 3)-c ( 9)-C( 1 0)-c { 15)0 (2 5)-c (9)-C (1 0) -c ( 1 1)0 (25)-c (9) -c ( 10) -c ( 1 5)C(5)-0(22)-C(23)-C(,.4)167.1-11.1- 16.3165.512.4- 174.9- 164.28.54.0- 175.5- 179.90.6-41.4- 164.8136.813.44.3-113.3124.87.1- 19.9167.4-151.136.36.022.8- 115.6- 153.4- 93.889.9139.4- 102.83.0- 170.5-115.870.738.48.6175.'i1.4- 83.3-171.7-12.6- 178.9- 174.812.2-1.2- 174.28.32.1- 175.44.7results of the anisotropic refinement (see Experimentalsection) are shown in Figure 2, which depicts the 25Cf11FIGURE 2 ORTEP view of the molecular skeleton of the adduct(5d) (hydrogen atoms not included) ; the thermal ellipsoids aredepicted according to the output of the last least-squares cycle(see text)probability ellipsoids.lO Bond lengths and angles notinvolving hydrogen atoms are listed in Table 1, and themore significant torsion angles are given in Table 2.Ananalysis of the planarity of the ring is provided in Table3. Tables of structure factors, atomic fractional co-TABLE 3Distances (A) of the ring atoms from their least-squaresinterpolating planes; arranged in the same order asthe defining atoms; e.s.d.s less than 0.006ring^ N(l)ring^ C(5a)Ring c C(2a)+0.046- 0.023+0.240PhCO -0.003PI1 of C(10)C(2) C(2a)C(6) C(7)C(3) C(4)C(11) C(12)-0.099 +0.074-0.004 +0.026-0.349 +0.296+ 0.003 - 0.001C(8b)- 0.065C(8a) C(8b)-0.016 +0.037C(5a) C(8b)- 0.095 +0.014C(14) C(15)0 +0.001ordinates, and thermal parameters are listed in Supple-mentary Publication No.SUP 21741 (12 pp., 1 micro-fiche).?Both Tables 2 and 3 clearly show the half-chair con-formation of ring c (in Table 2 the appropriate internaltorsion angles are labelled c). The phenyl ring of thebenzoyl group is strictly planar (Table 4). The distortionof the aromatic ring B from planarity (see also Table 3)is clearly connected with its fusion with the non-planarsystem AC.The angles between pairs of rings of thefused system are AB, 10.3"; AC, 13.0'; BC, 11.7'.The final distances range between 0.88 and 1.16 A,with fairly good angles. The shortest intermoleculardistances are listed in Table 4; some are remarkably* Work carried out at the Centro di Studio per la Cristallo-t For details of Supplementary Publications see Notice to10 C. K. Johnson, ORTEP, Oak Ridge National Laboratorygrafia stuttarale del C.N.R., Pavia.Authors No. 7, J.C.S. Pevkin I , 1975, Index issue.Report ORNL-3794, 19651252 J.C.S. Perkin Ishort and apparently relatively strong molecular inter-actions are involved.It is unfortunate that these new adducts are formed insuch low yields because, in addition to their theoreticalTABLE 4Shortest intermolecular distances (A) ; e.s.d.s lessthan 0.005Symmetry code :(i) x, 1 + Y, z(ii) -x, 1 - y , 1 - z(iii) - x , 1 - y, 2 - z(iv) - x , 2 - y, 1 - z(v) - x , 2 - y, 2 - 2N( 1) - * - O(25Y) 3.062C(2) - * * O(25v) 3.066C(2a) * - 0(25V)...3.290C(15) * - - H3(24I1l) 3.036O(17) - * H(7iV).- 2.842O(17) * - * H(11rdquo;rsquo;) 2.807O(17) - - H3(21*V) 2.577C(18) * * 0(2Zvrdquo;) 3.209C(18) - * H3(24*) 2.991O(l9) * * * HZ(21d) 2.706C(21) - * * H2(24ii) 2.895O(22) * - * H1(18Hfi) 2.762O(25) - - - H(2av) 2.672O(25) * * H(13ix). 2.745Hl(4) - * Hl(23Ursquo;) 2.479H2(18) * - - H3(24rsquo;) 2.641interest, they could provide a potential syntheticapproach to ergot-type precursors.EXPERIMENTAL1.r. spectra (Nujol mulls) were obtained with a Perkin-N.m.r.data were obtained Elmer 257 spectrophotometer.Properties ofPhysicalaspectCompd. yield ()I M.P. (ldquo;C)(2; Ar = Ph; 6-OMe) Soft white 158-160 0needles 72yellowishcrystals 8platelets 4(3; Ar = Ph; 6-OMe) Small 146-147 a(4; Ar = Ph; 5-OMe) White 111-113*(2; Ar = Ph; 6-NO,) Soft pale 16A155C(3; Ar = Ph; 6-NO,) Soft pale 159-160eyellowneedles 70yellowneedles 12(from dioxan) (Found: C, 65.5; H, 3.5; N, 9.7. C,,H,,N,O,requires C, 65.3; H, 3.45; N, 9.5).(l-Acetyl-2-oxoindolin-3-ylidene)acetophenones (1 ; R =Ac) .-These were prepared by acetylation of the l-unsubsti-tuted derivatives by the literature methods : (l-acetyl-2-oxoindolin-3-y1idene)acetophenone (Ar = Ph) ,14 (l-acetyl-2-oxoindol-3-ylidene)-~-methoxyacetophenone (Ar = p -MeO*C,H4),2 (1-acetyI-2-oxoindolin-3-ylidene)-~-nitroaceto-phenone (Ar = p-N02*C,H4) .2(l-Acetyl-5-methoxy-2-oxoindolin-3-ylide~ze) acetophenone(6a). This was obtained (45) as red-violet needles, m.p.147rsquo; (from acetic acid) (Found: C, 71.2; H, 4.8; N, 4.4.C,,H,,NO, requires C, 71.0; H, 4.7; N, 4.35), v,,17443, 1709s, 1659s, and 1620w cm-1 (C=O of lactam,acetyl, and ketone, and exocyclic C=C, respectively), in-sufficiently soluble for n.m.r.data to be obtained.(l-Acetyl-5-nitro-2-oxoindolin-3-ylidene) acetophenone (6b).This was obtained (77) as yellow crystals, m.p. 204-205rsquo;(from acetic acid) (Found: C, 64.4; H, 3.7; N, 8.5.C18-H12N20, requires C, 64.3; euro;3, 3.6; N, 8.35), vmx. 1 753s,1 722s, 1 669s, and 1 622w cm-1 (GO of lactam, acetyl, andketone, and exocyclic C=C, respectively), 8 8.06 (s, vinylicReaction of the Indolylideneacetophenones with Ethyl VinylEther.-General method. As in the previously reportedmethod,2 a suspension of the substrate (l) or (6) (4 mmol)in ethyl vinyl ether (12 ml) was heated at 100 lsquo;C in a Paarapparatus reaction times 1 and 1.5 h for (6a) and (6b)respectively. After cooling pure or nearly pure adduct ofH).TABLE 5dihydropyran- and dihydrofuran-type adducts1.r. (vlcrn-l)LI 1 Elemental analysis () (v(C=O) V(c=O) Y ( c = O )r , (acetyl) (lactam) (ketone)Found :Found :Found :Found :Found :C, 69.9; H, 5.9; 1712s Absent 1689sN, 3.7C, 70.55; H, 6.05; 1 703s Absent 1 672sN, 3.7C, 70.3; H, 6.0; 1700s 1756s AbsentN, 3.66C, 70.2; H, 5.9;N, 3.65C, 64.8; H, 5.0; 1715s Absent 1686sN, 6.9C, 64.85; H, 5.1; 1716s Absent 1683sN, 6.95C, 64.7; H, 4.95;N, 6.86C,,H,,NO, requiresC2,H,,N,06 requires0 From ethanol.b From light petroleum. C From benzene.by Dr. A. G. Invernizzi with a Perkin-Elmer R12A spectro-photometer (solvent, unless otherwise stated, CDCl,) .Microanalyses were performed by Dr. D. Maggi.(2-Oxoindolin-3-ylidene)aceto~henones.-The followingcompounds were prepared by literature methods : (20x0-indolin-3-ylidene)acetophenone,11 fi-methoxy-(Z-oxoindolin-3-ylidene)acetophenone,ll (2-oxoindolin-3-ylidene)-p-nitro-acetophenone,2 and (5-methoxy-2-oxoindolin-3-ylidene)-acetophenone.l2(5-Nitro-2-oxoindolin-3-ylidene)acetophenone. This wasobtained from amp;nitroisatin l3 and acetophenone by thereported method as yellow crystals (53y0), m.p.229-231rsquo;l1 H. G. Lindwall and J. S. Maclennan, J . Chem. Soc., 1932,54,4739.l2 S. Pietra and G. Tacconi, IZ Farunaco, Ed. Sci., 1968,15, 893.type (2) was collected and washed with diethyl ether.Crystalline mixtures of dihydropyrans of types (2) and (3)and benzindolones ( 5 ) were obtained as further crops fromthe concentrated mother liquors, after storage a t lowtemperature. Finally, the oily residue was chromatographedMerck Kieselgel(O.06-0.2 mm) ; cyclohexane-ethyl acetate(70 : 30) as eluant to give pure adduct of type (4) (firstfraction) and small amounts of mixtures of adducts oftypes (2) and (3) and, sometimes, ( 5 ) .Pure samples wereobtained by fractional crystallization from ethanol. Alladducts not previously described are reported in Tables 513 N. 0. Calvery, C. R. NolIer, and R. Adams, J . Amer. Chern.Soc., 1925, 47, 3059.l4 T. Kato, H. Yamanaka, and H. Ichikawa, Chem. andPharm. Bull. (Japan), 1969, 17, 4811976 1253and 6 and the n.m.r. spectra are summarized in Tables 7and 8.X-Ray A na1ysis.-Crystal data. C ~ ~ H ~ ~ N O S , M =393.443. Monoclinic, space group P2,/n, a = 12.557 (4),b = 12.734J4), G = 12.510(4) A, p = 92.28(4)", U =1 998.779 A3, 2 = 4, D, = 1.307 g ~ m - ~ , F(000) = Cu-K,radiation, A = 1.5418 A, graphite monochromator, ~ ( C U -I,) = 7.G6 cm-l.The cell parameters were determined by scanning rows(liOO), (OhO), (OOZ), (hOh), and (hOh) on a diffractometer, withCu-K, radiation up to 50deg;, and withStructure determination and refinement. The structurewas solved by direct methods, after application of MUL-TAN; 15 the solution was obtained with the set of signswith maximum likelihood. Refinement of the starting co-ordinates was carried out by full-matrix least-squares, untilconvergence, with a locally modified version of ORFLS l 6(scattering factors 17).No weighting scheme was applied.In the last least-squares cycle the secondary extinction co-efficient and the anisotropic thermal parameters of the non-hydrogen atoms were refined, in order to improve theboth positive and positional co-ordinates ; no particular physical meaning isTABLE 6Properties of benzcdindolones (5)1.r.(vlcm-1)Physical aspectCompd. yield ()I M.p. ("C)(5a) Soft white needles 166-167 a(5b) Soft white needles 161-162 a(Bc) Yellowish needles 181-182 a(5d) Pale yellow crystals 209-211 b(5e) Small white needles 181 ac3-41P-3141P--332-31Elemental analysis (yo) ;(c=o) v(c=o) +=ojr 8 (acetyl) (lactam) (ketone) LFound : C, 72.8; H, 5.8; N, 3.9 1702s 1769s 1689sC,,H,,NO, requiresFound : C, 70.35; H, 6.0; N, 3.6 1709s 1765s 1670sC,,H,,NO, requiresFound : C, 65.0; H, 5.05; N, 7.0 1698s 1781s 1684sC,,H,,N,O, requiresFound : C, 70.55; H, 5.96; N, 3.7 1695s 1763s 1678sC,,H,,NO, requiresFound : C, 64.95; H, 4.95; N, 7.0 1710s 1782s 1680sC2,H2,N,0, requiresC, 72.7; H, 5.8; N.3.86C , 70.2; H, 5.9; N, 3.56C, 64.7; H, 4.95; N, 6.85C, 70.2; H, 5.9; N, 3.55C, 64.7; H, 4.95; N, 6.85From ethanol. From dioxan.TABLE 7N.m.r. data for adducts of types (2)-(4) Et groups designated CH,HbC(H,),; for Hd- see formulaeChemical shifts (6) Coupling constants (Hz)A rCompd. H d H,Hf Hg Ha Hb Hc ORfe AC ArH- )do f Jdf Jeg 4- Jti -Jab Jo (vL)(2; Ar = Ph; 6-OMe) 5.37 2.6 4.57 3.80 3.52 1.16 3.66 2.60 6.4-8.4 7.9 13.6 9.4 7.1(3; Ar = Ph; 6-OMe) 5.62 2.3 4.95 3.96 3.73 1.25 3.57 2.63 6.26-8.4 7.3 14.6 10.6 7.0(2; Ar = Ph; 6-NO2) 5.47 2.5 4.63 3.89 3.60 1.13 2.67 7.3-8.6 6.6 12.2 9.3 7.3(3; Ar = Ph; 6-NO,) 6.63 2.3 5.01 3.99 3.79 1.28 2.70 7.5-8.6 6.7 14.5 9.4 7.3(4; Ar = Ph; 5-OMe) 4.79 2.5 5.67 3.96 3.62 1.22 3.75 2.66 6.65-8.25 9.8 9.8 7.2TABLE 8N.m.r.data for the adducts (5) Et designated C(HB),*C(H~),; for Ha-d see formula ( 5 ) Chemical shifts (6) Coupling constants (Hz)c L c 7Compd. Ha Hb Ho Hcp Hd HA HB AC OMe ArH ' ' Jab Jbc Jbc# Jcd Jcrd - J c v JAB( 5 4 4.29 3.94 2.05 2.40 4.59 3.68 1.24 2.55 7.2-8.3 10.0 10.0 4.0 4.0 4.0 14.0 7.04.30 3.88 2.05 2.39 4.58 3.82 1-25 2.55 3.87 6.8-8.4 10.0 9.3 4.3 4.3 3.4 14.7 6.7 (5b)(5c)4.29 3.85 1.88 2.51 4.74 3.75 1.22 2.54 3.88 6.7-8.25 10.8 10.6 2.7 2.7 2.7 14.5 7.0 ( 5 4(5e)4.26 3.96 2.09 2.42 4.64 3.72 1.26 2.55 7 . 1 U . 5 10.5 9.9 3.9 4.3 3.3 14.2 6.84.36 3.96 1.97 2.25 5.41 * 3.67 1.14 2.58 7.4-8.3 10.6 10.7 3.6 4.0 2.0 14.7 7.1* Equatorial proton deshielded by NO,.negative 8 values for assessing the zero of the correspondingcircle.Intensity measurements. 1302 reflections with 8 (Cu-K 40" were collected with a Philips PWllOO automaticdiffractometer (from a crystal of approximately cubic shapeand dimensions: 0.032 x 0.035 x 0.038 cm); the workingconditions were as follows: w-28 scan mode, o range 1.4',scan speed 0.05" s-1; 0.06" of background radiation wasmeasured on each side of the peak. The 1 127 reflectionswith I 3a ( I ) were considered unobservably weak.Three reference reflections were monitored every 2 h andno decomposition was observed. The intensities were notcorrected for absorption.lS P. Main, M. M. Woolfson, and G. Germain, ' MULTAN-aComputer Program for the Automatic Solution of CrystalStructures,' Universities of York, England, and Leuven, Belgium,1971.claimed for individual Bij values, and accordingly they arenot reported.All the hydrogen atoms were found as the more prominentpeaks in a (F, - F,) Fourier synthesis; they were refinedisotropically.We thank Professor P. Griinanger for discussions andsuggestionsand Professor A. Coda for suggestions and facilitiesfor solving the crystal structure. The Consiglio Nazionaledelle Ricerche (C.N.R., Rome) is thanked for financial6/2177 Received, 10th November, 19751support.l6 W. R. Busing, K. 0. Martin, and H. A. Levy, ORFLS, Oakl7 H. P. Hanson, F. Herman, J. D. Lea, and S. Skillman, ActaRidge National Laboratory Report ORNL-TM-305, 1962.Cryst., 1964, 17, 1040