摘要:
2232 J.C.S. Perkin 1The Chemistry of Terpenes. Part XX.l Autoxidation of (+)-Car-3-eneBy David A. Baines and Wesley Cocker," University Chemical Laboratory, Trinity College, Dublin 2Autoxidation of (+)-car-3-ene in the presence or in the absence of cobalt stearate affords the following com-pounds, their yields being dependent upon the method of decomposition of the initial hydroperoxides : (+)-3a,4a-epoxycarane, (-) -8-methoxy-m-mentha-4,6-diene, (-) -car-4-en-3a-ol, (-) -8-methoxy-p-mentha-1.5-diene, eucarvone, (-) -car-4-en-3p-ol, (+) -cis-caran-SP-ol, (+)-car-2-en-4-one, (-) -rn-mentha-4,6-dien-8-ol,(+)-p-mentha-I ,5-dien-8-01, 3,6,6-trimethylcyclohepta-2,4-dienone, (+)-car-3-en-2-one, 8- hydroxy-m- and-p-cymenes, and (-)-car-3-en-5-one, in this order of elution from a Carbowax g.1.c.column. A reaction sequenceis suggested. Reaction of (+) -car-3-ene with selenium dioxide in pyridine gives (+)-p-mentha-I ,5-dien-8-ol asthe major product.IN 1931, Owen and Simonsen isolated m-mentha-6,8-dien-5-one (2) from the autoxidation of (+)-car-3-ene(1) with cobalt resinate as catalyst. They also suspectedthe presence of rn-mentha-4,6-dien-8-01(3) in the product.However, they regarded car-3-en-5-01 (4) or the corres-ponding ketone (5) as the principal autoxidation product,but deemed these to be unstable, readily rearranging to7 Absolute configurations are given for products we obtainedSome reports do not specify the car-3-ene from (+)-car-3-ene.used in the experiments described.rn-mentha-6,8-dien-5-01 (6) or the corresponding ketone(2) and P-mentha-l,8-dien-3-01 (7) or the correspondingketone (8).Since the degree of stability of (-)-car-3-en-5-one (5) t has been establi~hed,~ we have reinvesti-gated the autoxidation both in the presence and in theabsence of catalyst.1 Part XIX, W. Cocker and D. H. Grayson, J.C.S. Perkin I ,2 J. Owen and J. L. Simonsen, J , Chern. SOC., 1931, 3001.W. D. P. Burns, M. S. Carson, W. Cocker, and P. V. R.1976, 1217.Shannon, J. Chem. SOC. ( C ) , 1968, 30731975 2233Three groups of workers have, in recent years, studiedthe products of autoxidation of car-3-ene. Car-3-en-5-ylhydroperoxide (9) was isolated and converted into car-3-en-5-01 In the presence of lead tetra-acetate and10 7(11 (21R-0 ( 3 1 R-H (L)R=H,CH (7) R=H,OH(61 R=H,OH (271 R=Me (5)R=0 (81R=0(9) R = H ,C2K(12) R=H,OH (13)123) R=O (lL)R= H(281 R=Me(291 R=E tC02 Me COz Me(261 1301 (311 (32 1manganese dioxide, autoxidation gave eucarvone (lo),car-3( lO)-en4-01 (1 1), and 3,6,6-trimethylcyclohepta-2,4-dienol (12).In the latest series of studies light wasused as an initiator; eleven hydrocarbons and eucarvone4 B. V. Erofeev and A. I. Chirko, Uchenye Zafiski Belorus.Gosudarst. Univ. im V . I . Lenina, Ser. Khim., 1956,29, 15. (Chem.A bs., 1960,54, 6789e).B. A. Arbuzov, 2. G. Isaeva, and V. V. Ratner. DokladyAkad. Nauk S.S.S.R., 1960, 154, 683 (Chem. Abs., 1961, 55,6616i).6 I. I. Bardyshev, V. S. Shavyrin, V. S. Pankova, and G. V.Kabatova, Gidroliz. desokhim.Prom., 1968, 21, 12 (Chem. Abs.,1968, 89, 69,392g).7 V. S. Shavyrin, I. I. Bardyshev, andV. V. Budylina, Sb. Tr.,Tsent. Nauch.-Issled. Prockt. Inst. desokhim. Prom., 1968,19, 11(Cher Abs., 1969, 71, 102,023t).C. Bardyshev and V. S. Shavyrin, Sb. Tr., Tsent. Nauch.-Prockt. Inst. desokhim. Prom., 1969, 20, 23 (Chem. Abs.,5, 20,639s).(lo), the dienol(12), carvone (13), +-rnentha-lJ5-dien-8-ol(14), and cis-caran-4-one (15) were identified.Autoxidation in the Presence of Cobalt Stearate (Table 1 ) .-In our hands, autoxidation of (+)-car-3-ene (1) in thepresence of catalyst, followed by reduction, by fivemethods, of the mixture of hydroperoxides, gave productscontaining (g.1.c.) up to twenty components. Theirnumber and abundance varied with the method of re-ductive work-up.The most abundant product, whose retention time(tR) relative to that of eucarvone was 1.73, was a 4 : 1mixture of (-)-m-mentha-4,6-dien-8-01 (3) and (+)+rnentha-1,5-dien-8-01 (14).Chromatography gave pure(3), characterised as its adduct with maleic anhydride:but (14) was always contaminated with (3). Reactionof the mixture of dienols (3) and (14) with dimethylacetylenedicarboxylate lo gave dimethyl 3-methylphthal-ate (16), dimethyl 4-methylphthalate (17), and dimethylPmethy1-3,6-dihydrophthalate (18) .ll The dihydro-phthalate (18), presumably resulting from the reactionof the acetylenic ester with isoprene formed thermallyfrom 2-methylbut-3-en-2-01 (Scheme 1), absorbed in theU.V. at 215 nm and in the i.r.at 1 725, 1 650, 1 590, and790 cm-l. N.m.r. signals at ’i 8.30 (3 H, s, MeC=C),7.12 (4 H, s, CH,), 6.30 (6 H, s, C0,Me) , and 4.60br (1 H,H-C=C) are in accord with its structure.(+)-P-Mentha-l,5-dien-8-01 (14) was prepared forcomparison purposes by reaction of (+)-car-3-ene (1)with selenium dioxide (see later).The maleic anhydride adduct of the mixture of dienols(3) and (14) was readily resolved on silica giving productsidentical with those derived from pure specimens of thedienols.The dienols (3) and (14) afforded, respectively, 8-hydroxy-m-cymene (19) and its &isomer (20) in air.Further chromatography on silica of the mixture ofautoxidation products derived from (+)-car-3-ene gave(+)-3ct,4a-epoxycarane (21), eucarvone (lo),, (+)-car-%en-4-one (22), 3,6,6-trimethylcyclohepta-2,4-dienone(23), 8-hydroxy-m-cymene (19), 8-hydroxy-~-cyrnene(20), and (-)-car-3-end-one (5).The properties of thesecompounds are well do~umented.~J~(-)-Car-4-en-3a-o1 (24),13 (-)-car-4-en-3p-o1 (25), and(+)-cis-caran-5/3-01 (26)14 were isolated from the autoxi-dation product by preparative g.1.c. The properties ofthe allylic alcohol (25) l5 are not well described. Bothalcohols (24) and (25) absorb in the i.r. near 3 400, 1 630,and 730 cm-l. The n.m.r. spectrum of (24) has signals9 K. Gollnick, G. Schade, and G. Schroeter. Tetrahedron, 1966,10 E. D. Parker and L. A. Goldblatt, J . Awer. Chem. SOC.,N. P. Sopov and V. S. Miklashevskaya, Zhur. obshchei12 W. Cocker, D. P. Hanna, and P.V. R. Shannon, J. C h n .13 K. Gollnick, S. Schroeter, G. Ohloff, G. Schade, and G. 0.14 W. Cocker, P. V. R. Shannon, and P. A. Staniland, J . Chem.16 H. Kuczynski and K. Marks, Roczitiki Clzern., 1960, 43, 94322, 139.1950, 72, 2151.Khim., 1966, 26, 1914 (Chem. Abs., 1967, 51, 4968a).SOC. (C), 1968, 489.Schenck, Annalen, 1966, 687, 14.SOC. (C), 1967, 485.(Chem. Abs., 1969, 71, 61,558a)2234at 7 9.16 (3 H, s, 9-H,), 8.9 (6 H, s, 8- and 10-H3), and4.31 (2 H, s, HC=CH); that of its 3-epimer (25) hassignals at z 9.05 (3 H, s, 9-H,), 8.9 (3 H, s, 8-H3), 8.75(3 H, s, 10-H,), 4.57 (1 H, d, J 10 Hz, 5-H), and 4.32(1 H, d, J 10 Hz, 4-H). In each case the C-9 methylgroup is shielded by the double bond, but in (25), theeffect of the p-hydroxy-group is to shift the signal of thismethyl group to lower field.In (24), the C-10 methylgroup is shielded by the cyclopropane system. Theunsaturated alcohols (24) and (25) gave (+)-caran-3a-and -3p-01, respectively, on hydrogenation.M e wHO $J(31HOMe02C,J.C.S. Perkin Iwithout catalyst led to increased yields of the majorproducts, the dienols (3) and (14), but the ratio of thesewas changed from 4 : 1 to 5 : 4. They were eluted from asilica column as a single fraction and their yields wereassessed by the amounts of the dimethyl phthalates,(16) and (17), readily separable on silica, which the mix-ture afforded.Work-up of the mixture of hydroperoxides with po-tassium iodide in acetic acid [method (g)] gave fair yieldsof two compounds of tn 0.55 and 0.58 which could notbe adequately separated by preparative g.1.c.The more o.... C02MeCH,=CMeCH=CH2 -$t C02Me(18)OH(1L)SCHEME 1 i, MeO,C*C:CCO,MeIn the work-up procedure in which borohydride inmethanol was used [Table 1, method (b)], and the excessof borohydride was destroyed with dilute acid, the majorproduct was (-)-8-methoxy-m-mentha-4,6-diene (27)(cf. ref. 16). It absorbed in the U.V. at 264 nm (log E3.6) and its n.m.r. spectrum had signals at T 8.95 (6 H,s, Me&), 8.25br (3 H, s, MeC=C), 6.90 (3 H, s, MeO), and4.4 (3 H, m, HC=C). It was rapidly aromatised in air.The compound of t R 0.86 was possibly 8-methoxy-P-mentha-l$-diene (28) but its instability prevented identi-fication. However when the work-up, by method (b),of the autoxidation product was carried out in ethanol,(+)-8-ethoxy-$-mentha-l,5-diene (29) was obtained,identical with a sample prepared by reaction of (+)-car-3-ene with selenium dioxide in ethano1.l'Work-up of the autoxidation product from (+)-car-3-ene with water [Table 1, method (c)], with cold alkali[method (d)], or with hot alkali [method (e)], gave pro-ducts which varied sequentially.Apart from the dienols(3) and (14), work-up with water gave (-)-car-3-en-5-one ( 5 ) , (+)-car-2-en-4-one (22), and (+)-car-3-en-2-one(30). Alkali caused rearrangement of (5) and (30) to3,6,6-t rimethylcyclohepta-2,4-dienone (23) and eucarv-one (lo), respectively.3 The fate of (+)-car-2-en-4-one(22) has still to be examined.A u t o d a t i o n of (+)-Car-S-ene (1) in the Absence ofCatalyst (Table 2) .-Autoxidation of (+)-car-=J-enel6 R.K. Murray and K. A. Babiak, Tetrahedron Letters, 1974,311.polar compound was identified as P-isopropenyltoluene(31) and the other was probably its m-isomer (32). Themixture of these showed a U.V. maximum at 820 cm-lresulting from aromatic P-disubstitution and maximaat 890, 790, and 725 cm-l resulting from m-disubstitu-tion.12 Dehydration of the mixture of 8-hydroxy-m-(19) and -$-cymene (20), also obtained in the autoxida-tion, afforded the anhydro-compounds (32) and (31),respectively .The hydroperoxides and the initial products derivedfrom them are clearly of such instability that differentmodes of work-up lead to variations in yields of products.The mild work-up conditions using water alone givehigher yields of the ap-unsaturated ketones (5), (22), and(30).In the case of the uncatalysed autoxidation, work-up with water also gave (+)-3a,4a-epoxycarane (21) infair yield.Free-radical oxidation of allylic centres arising fromthe use of triplet oxygen is unlikely to give hydroper-oxides with migration of the double bonds.ls Thus theinitial autoxidation products of (+)-car-3-ene (1) arelikely to be the hydroperoxides (33) and (34), and theepoxide (21). However, the other carane hydroper-oxides (35) and (36) can be formed from (33) and (34) byl7 2. G. Isaeva, B. A. Arbuzov, and V. V. Ratner, Izvest.Akad. Nauk S.S.S.R.. Ser. khim.. 1965. 475 (Chem. Abs..1965.63, 633f).vol. 2, p. 22.l8 D. Swern, 'Organic Peroxides,' Wiley, New York, 19711975 2235allylic rearrangement .19 The subsequent decomposi-tion products of the hydroperoxides are shown in Scheme2.Reduction of the four hydroperoxides (33)-(36) willgive the alcohols (37), (38), (24), and (39), respectively.Of these only (-)-car-4-en-3a-o1 (24) is reasonablystable. Of the others, the alcohol (37) will rapidlyrearrange to the dienol (3) and the alcohols (38) and (39)will similarly afford the dienol (14); cf. the ready re-arrangement of caran-2- and -5-01s with acid.12The presence of ( -) -car-4-en-3 B-01 (25) among theautoxidation products can be explained on the basis ofthe reduction of (-)-car-3-en-5-one (5) by borohydrideto the alcohol (40) followed by allylic rearrangement.(-)-Car-4-en-3a-o1 (24) and its epimer (25) are stableto neutral or alkaline work-up, but they readily form thedienol (3) in the presence of a trace of acid.gThe formation of the epoxide (21) is in competitionwith that of the hydroperoxy-compounds.Thus in theslower, uncatalysed autoxidation of (+)-car-3-ene, ahigher yield of epoxide is formed than in the catalysedreaction.Other secondary rearrangements which may occurinvolve the a@-unsaturated ketones (5), (22), and (30)Caran-5p-01 (26) is probably formed by reduction byborohydride of (-)-car-3-en-5-one (5).Oxidation of (+)-car-3-ene (1) with selenium dioxidein pyridine gave a good yield of (+)-p-mentha-l,5-dien-8-01 (14), and smaller yields of (-)-car-3-en-5-one (5)(trace), eucarvone (lo), 8-hydroxy-p-cymene (20), (+) -car-3-en-2-one (30), and 9-isopropenyltoluene (31) (Table3).We isolated no m-menthane derivatives ; a similarspecificity was found by earlier workers,17 who, by usingethanol as solvent, obtained a complex mixture of pro-ducts. The formation of (+)-+-mentha-l,5-dien-8-01ii:,14)SCHEME 3(14), and that of eucarvone (10) and its precursor (+)-car-3-en-2-one (30), can be expressed as proceedingthrough the common intermediate shown in Scheme 3.The presence of only a trace of product derived viaoxidation of (+)-car-3-ene (1) at C-5 (a much less hin-dered position than C-2) argues against initial allylicoxidation by selenium dioxide at the latter position.EXPERIMENTAL1.r. spectra were measured either for liquid films (L)or for Nujol mulls (M), U.V. spectra for solutions in ethanol,n.m.r.spectra at 60 MHz for solutions in CCl,, and massspectra with a Hitachi-Perkin-Elmer RMS4 instrument.Optical rotations were measured for solutions in CHC1,.Analytical g.1.c. was carried out on a 2 m x 3 mm 20%Carbowax 20M on Chromosorb W column at 150 "C andpreparative g.1.c. on a 2 m x 8 mm 20% Carbowax 20 Mcolumn at 150 "C. Cobalt(I1) stearate was prepared as des-cribed.20 Additional i.r. and mass spectral data, for com-pounds marked with an obelus (t ) , are available in Supple-mentary Publication No. SUP 2 15 13 ( 11 pp., 1 microfiche). *Autoxidation of (+)-Car-3-ene (1) ; General Procedures.-(A) With catalyst.Oxygen was bubbled through a finesintered glass disc, a t 40 ml min-l, into a rapidly stirredsolution of cobalt(I1) stearate (2 g) in (+)-car-3-ene (50 g;[a.]D30 + 14.7" (G 0.2)) at 15 "C, kept under slight pressure bya mercury bubbler. After 7.5 h the product (peroxidenumber ca. 400) was worked up by one of the methods des-cribed below.(B) Without catalyst. The method was as in (A), but theoxygen flow rate was 100 ml min-l, temperature 50-60 "C,and reaction time 6 h. The peroxide number was then--op1 22 j(10).*OH(25)OH[LO 1 . - .SCHEME 2 5 500.Work-up techniques. The same quantity of autoxidatioJ.C.S. Perkin Ia further 2 h, water (600 ml) was added and the product wascollected in ether (3 x 200 ml).(b) As in method (a) exceptthat the excess of borohydride was destroyed with hydro-chloric acid (2N; 250 ml). Water (250 ml) was added, theproduct was extracted with ether (3 x 200 ml) and the ex-tract was washed with sodium hydrogen carbonate (5% ;2 x 100 ml) and water (2 x 100 ml). (c) Water (500 ml)was used; the mixture was rapidly stirred for 4 h, and ex-tracted with ether (3 x 250 ml). (d) Sodium hydroxideTABLE 1Autoxidation of (+)-car-3-ene in the presence of catalysttR(g.1.c.)0.640.720.760.820.861 .o1.171.221.391.471.581.731.902.102.162.352.542.853.344.0Conditions of work-up and % yield tProduct (a) (b) (4 ( 4 (4(2i) 1.7 T 3.0 2.4 3.8T 1.5 1.8 1.0(2I) 1.1 44.5T 0.5 T TT T 1.2 11.53.2 T T 0.711.1 1;;; * 1;5(10) T(28) 5.11.1T 0.5(26) 10.0(22) 6.3 3.0 16.0 12.8 2.8(3), (14) 31.8 27.0 21.0 19.4 21.0(23) 3.8 11.4 48.0(30) 10.1 6.4 14.0 16.6 3.51.7T 2.0 2.4 T2.0T T T(19), (20) 3.6 4.5 2.0 3.9 2.8(5) 11.2 39.5 29.1 4.9* Tentative assignment.t T = Trace.TABLE 2Autoxidation of (+)-car-3-ene in the absence of catalysttR Conditions of work-up and % yield t(g.1.c.) (00::: 0.640.720.760.820.860.941.01.131.171.391.471.581.732.012.152.362.545.843.343.784.05.6 17.07.6 49.52.71.3 9.59.1 15.01.0 1.40.52.0 10.968.0 35.5 12.36.42.5 10.92.5 2.727.2* t See Table 1.(94.322.21.10.61.13.226.70.68.616.11.713.9(id10.013.0T3.7TTT0.68.115.22.26.2T0.626.11.6T12.7solution (10% ; 500 ml) was used; the mixture was stirredfor 4 h and extracted with ether (3 x 250 ml), and the extractwashed successively with hydrochloric acid ( 2 ~ ; 260 ml) ,sodium hydrogen carbonate (5%; 260 ml), and water (250ml).(e) As in (c) except that the alkaline mixture wasrefluxed for 4 h. (f) The peroxide mixture was slowlyadded to a stirred solution of sodium disulphite (40 g), inwater (300 ml), kept a t 0 "C. Stirring was continued for 1 hlonger and the mixture was worked up as in (c). (g) As in(f), the reducing agent being a stirred solution of potassiumiodide (20 g), water (200 ml), and acetic acid (20 ml), kept at0 "C. After 1 h, the mixture was extracted with ether (3 x250 ml), and the extract was washed with sodium hydrogencarbonate (5%; 4 x 250 ml) and water (2 x 250 ml).Sfiecific Exam$les.-(A) Autoxidation in the firesence ofcatalyst.Work-up by method (a) gave an oil (48 g) whichon distillation at 0.7 mmHg gave (+)-car-3-ene (22 g), b.p.30", other volatile products (16.6 g), b.p. 60-llO", and aresidue (7.8 g) which was not investigated.The product from method (a) whendistilled a t 0.2 mmHg, gave (+)-car-3-ene (20.5 g), b.p. 21-25", other volatile products (21.1 g), b.p. 35-70", and a resi-due (9 g).The fraction of b.p. 60-110" at0.7 mmHg from (A) was redistilled a t 0.8 mmHg givingfraction (i) (6.7 g), b.p 65-78', and fraction (ii) (3.5 g), b.p.78-110°. Fraction (ii) (2.8 g) was chromatographed onsilica (100 g) and eluted with increasing amounts of ether inlight petroleum giving ( +)-3aJ4a-epoxycarane (21) (0.1 g;6% ether), [a]D20 + 1 2 .1 O (lit.,s + 12.5") : (+)-car-2-en-4-one (22) (0.3 g; 15% ether), [alDZo +360° (c 3.6)+428) ; (+)-car-3-en-2-one (30) (0.2 g ; 20% ether), [&]Dao+251" (G 2.5) (lit.,3 3-243"); eucarvone (10) (0.01 g ; 20%ether) ; 3,6,6-trimethylcyclohepta-2,4-dienone (23) (0.15 g ;20% ether) ; (-)-rn-mentha-4,6-dien-8-01 (3) and (+)-$-mentha-l,5-dien-8-01 (14) isolated as a mixture (0.6 g, 25%ether) (see below): and (-)-car-3-en-5-one (5) (1.1 g, 30%ether),[aID2O -244" (c 20) (lit.,3 -271"). The ap-unsaturatedketones and dienones were identical (g.l.c., i.r., and n.m.r.)with authentic specimen^.^Chromatography of frac-tion (i) (3 g) on silica (100 g) gave the range of compoundsdescribed above and a mixture of 8-hydroxy-rn-cymene (1 9)and 8-hydroxy-p-cymene (20) (0.2 g ; 20% ether).Rechro-matography of this mixture on silica (10 g) gave first afraction rich in the $-isomer (20) l7 (for n.m.r. data seeSupplementary Publication) and finally a fraction rich inthe m-isomer (19) .a Each was identical (g.1.c. and i.r.) withan authentic specimen.The mixture (0.6 g) ofthis compound and p-mentha-1,5-dien-8-01 (la), obtained asdescribed above, rechromatographed on silica (40 g), gave(--)-m-mentha-4,6-dien-8-01 (3),t [,IDao - 158" (c 2.5) (lit.,B-165.Q0), Lx. 264 nm (log E 3.7), v,, (L) 3 360 and 1 650cm-1, z 8.87 (6 H, s, Me&), 8.23 (3 H, s, MeC=C), and 4.1-4.7 (3 H, m, olefinic H).Its maleic anhydride adduct t(0.3 g) obtained by refluxing the dienol (0.25 g) with maleicanhydride (0.2 g) in benzene (10 ml), had m.p. 118-119'(from acetone-benzene) (lit.,B 118"), [aJDZo -47" (lit.,B -5OO) ,v,, (N) 1 845 and 1 775 cm-l (anhydride) (Found: C, 67.3;H, 7.4. Calc. for C&1@4: C, 67.2; H, 7.25%).Reaction of the mixture of dienols (3) and (14) with dimethylacetylenedicarboxylate. The dienols (1.4 g) and the ester(2.2 g) were refluxed for 2.6 h. The product (2 g) waschromatographed on silica (50 g) and eluted with increasingamounts of ether in light petroleum. Dimethyl 4-methyl-3,6-dihydrophthalate (18) t (0.3 g) was eluted first (15%ether), m/e 210 (M+) (Found: C, 62.8; H, 6.6.Calc. forCllHl4O4: C, 62.85; H, 6.7%). Elution with 30% ethergave dimethyl 3-methylphthalate (16) t (0.8 g), v- (L)1 730 and I590 cm-l, z 7.69 (3 H, s, ArMe), 6.18 (6 H, s,MeO), 2.6-2.8 (ZH, m, ArH), and 2.2-2.42 (1 H, m, ArH),m/e 208 (M+) (Found: C, 63.1; H, 6.8. Calc. for CllHl,O,:(B) Without catalyst.Isolation offiroducts.8-Hydroxy-m- and -p-cymenes.(--)-m-Mentha-4,6-dien-8-01 (3)1975 2237C , 63.45; H, 5.8%). Elution with 40% ether gave dimethyl4-methylphthalate (17) t (0.5 g), vmx (L) 1725 and 1600cm-1, z 7.65 (3 H, s, ArMe), 6.21 (6 H, s, MeO), and 2.4-2.95(3 H, m, ArH), m/e 208 (M+) (Found: C, 63.2; H, 5.6.Calc. for CIlH12O4: C, 63.45; H, 5.8%).This compound t (ta 0.82) wasisolated by preparative g.1.c.as a liquid, vmx. 3 380 and1 630 cm-l.The un-saturated alcohol (15 mg) in ethyl acetate (2 ml) washydrogenated over palladised charcoal (5% ; 30 mg)during 1 h, giving (+)-caran-3cc-ol (10 mg) 21 as the onlyproduct (g.1.c.)The 3p-01 t (tB 1.17) was isolatedby preparative g.1.c. as a liquid, vmX. (L) 3 350 and 1 630 cm-l.Thiswas performed as for (24) giving the saturated alcohol 21 asthe only product.(+)-cis-Caran-5#3-01 (26). The 5p-01 ( t ~ 1.47) l4 wasisolated by preparative g.1.c.( -)-8-Methoxy-m-mentha-4,6-diene (27). Compound(27) t (tB 0.72), isolated by preparative g.1.c. - 14",vmx. (L) 2 810 and 1640 cm-l, m/e 166 (M+) (Found: C,79.95; H, 10.9.Car-3-ene (50 g)was autoxidised in the presence of catalyst and worked upby method (b), with ethanol instead of methanol.Threemain products were observed on g.l.c., the main fractionbeing the mixed dienols (3) and (14). Preparative g.1.c. ofthe least abundant fraction gave (+)-8-ethoxy-p-mentha-1,5-diene (29) tJ17 b.p. 40" a t 0.25 mmHg, LX. 264 nm (log E3.45), v,, 1650, 1600, 745, and 730 cm-1, z 8.93 (6 H, s,Me,C), 8.93 (3 H, t, J 7 Hz, CH,CH,O), 8.34 (3 H, s,MeC=C), 7.30-8.20 (3 H, m, CH, and CH), 6.7 (2 H, q, J7 Hz, CH,O), 4.67br (1 H, s, HC=C), and 4.32 (2 H, s,HC=CH), m/e 180 ( M f ) (Found: C, 79.7; H, 11.0. Calc.for C12H2,0: C, 79.9; H, 11.2%), identical (g.l.c., i.r., andn.m.r.) wikh a specimen prepared by the reaction of (+)-car-3-ene with selenium dioxide in ethan01.l~m- (32) and p- (31) Isopropenyltoluene.These wereisolated by preparative g.1.c. as a 7 : 5 mixture from theuncatalysed autoxidation reaction [work-up by method (c) J.The mixture showed v,,(L) 2 860, 1 620,l 595,l 570,l 510,1 490, 1 440,l 300,l 230,l 110,890,820, 790, and 725 cm-1.21 P. J. Kropp, J . Amer. Chem. Soc., 1966, 88, 4926; W.Cocker, D. P. Hanna, and P. V. R. Shannon, J . Chem. Soc (C),.1969, 1302.(-)-Car-4-en-3a-o1 (24).Reduction of compound (24) to (+)-caran-3or-oZ.(-) Car-4-en-3p-oZ (25).Reduction of compound (25) to ( +)-caran-cis-3#3-01.Calc. for CllH,,O: C, 79.5; H, 10.9%).(+ )-8-Ethoxy-p-mentha- lJ5-diene (29).A similar mixture of hydrocarbons was obtained by stirringa mixture (1 g) of 8-hydroxy-m-cymene ( 19) and its p-isomer(ZO), acetone (25 ml), and water (25 ml) for 20 min withsulphuric acid (10 ml) at 15 "C.Reaction of (+)-Car-3-ene (1) with Selenium Dioxide.-Powdered selenium dioxide (80 g) was added over 0.5 h to astirred solution of (+)-car-3-ene (100 g) in dry pyridine (250ml) a t 70 "C.The mixture was refluxed for 3 h and distilledin steam, and the distillate (2 1) was extracted with ether (3 x500 ml). The extract, washed with hydrochloric acid (10% ;2 x 500 ml), sodium hydrogen carbonate ( 5 % ; 2 X 500ml), and water (500 ml), dried, and distilled a t 0.2 mmHg,gave (+)-car-3-ene (32.5 g) , b.p. 25-35', oxidation products(39.5 g), b.p. 35-85", and a residue (9 g) which was notfurther investigated. The second fraction contained (g.1.c.)the components shown in Table 3. The oxidation pro-TABLE 3Oxidation of (+)-car-3-ene with selenium dioxide inpyridine0.68 (31)1.00 (10)1.73 (14)2.14 (30)2.90 (20)4.0 (6)ta (g.1.c.) Product and % yield t11.46.01 .o 1.051.40 2.456.412.31.810.7T2.48t T = trace.ducts were absorbed on silica, eluted with ether-lightpetroleum mixtures, and compared (g.l.c., i.r. , and n.m.r.)with authentic specimens.(+)-p-Mentha-lJ5-dien-8-o1 (14) t had [aID2O + 183.5" (G3.1), lmX 264 nm (log E 3.4), vm,(L) 3 350, 1 645, 795, and715 cm-l, 7 8.85 (6 H, s, Me&), 8.3br (3 H, s, MeCZC), 7.82(2 H, m, CH,), 7.45 (1 H, m, CH), 4.6br (1 H, s, HC=C), and4.22 (2 H, s, HC--CH), m/e 152 (M+). The maleic anhydrideadduct t of the dienol (14) consisted of needles (from ether),m.p. 98", [aID2O +4", vm,(N) 3 540, 1 835, and 1 775 cm-l(Found: C, 67.4; H, 7.0. Cl4HI8O4 requires C, 67.2; H,7.25%).We acknowledge the award of a Post-Doctoral Fellowshipby the Department of Education of the Republic of Ireland(to D.B.).[6/872 Received, 9th May, 1975
ISSN:1472-7781
DOI:10.1039/P19750002232
出版商:RSC
年代:1975
数据来源: RSC