摘要:

1977 1505Chemical Investigation of Ceylonese Plants. Part 27. t Extractives ofCalophyllum cuneifolium Thw. and Calophyllum soulattri Burm. f.(Guttiferae)By Sarath P. Gunasekera, Gamini S. Jayatilake, Sathiadevan S. Selliah, and M. Uvais S. Sultanbawa.'Department of Chemistry, University of Sri Lanka, Peradeniya Campus, Peradeniya, Sri LankaThe bark and timber extractives of C. cuneifolium Thw. and C. soulattri Burm. f. have been studied. The barkextract of C. cuneifolium Thw. yielded calabaxanthone (1 ), trapezifolixanthone (2). taraxerol, simiarenol, friedelin,and a solid bark acid identified as isoapetalic acid (4a). The timber extract yielded 1,3.5-trihydroxy-2-(3-methyl-but-2-eny1)xanthone (6a). six known xanthones, and p-sitosterol. The bark extract of C.soulattri Burm f. gavea new coumarin alcohol, soulattrolide (1 3a), taraxerol, taraxerone, and B-sitosterol. The timber extract affordedfour known xanthones and the trihydroxyxanthone (6a).WE have already reported studies on six endemicCalophyllum species of the family Guttiferae. We nowdescribe results on two other Calophyllum species, bothnow considered to be endemic to Ceylon.2Calophyllum cuneifolium Thw.-Bark extractives. Thelight petroleum extract of the bark was separated intosodium carbonate-soluble and -insoluble fractions. Thelatter on separation on a silica gel column gave twoyellow pigments, (3-sitosterol, friedelin,3 taraxerolJ4 andp-~imiarenol.~?~ The last four compounds were identicalwith authentic samples. p-Simiarenol was convertedinto its acetate and into simiarenone which were alsoidentical with authentic samples.This is the first reportof the presence of p-simiarenol in this family.' The twoyellow pigments were identified as calabaxanthone 1u (1)and trapezifolixanthone l e (2) by comparison withauthentic samples.Me0From the sodium carbonate-soluble fraction a greenishyellow solid, m.p. 225-227", M+ 388, was obtained.It gave a green colouration with iron(m) chloride andshowed i.r. absorption at 3 500 (OH), 1 700 (CO,H), and1 645 cm-1 (conjugated CO). The U.V. spectrum wassimilar to those of blancoic (3a) and apetalic acids (3b)(Table 1). I t gave a crystalline methyl ester with diazo-? Part 26, S. P. Gunasekera, M. U. S. Sultanbawa, and S.Balasubramaniam, Phytochemistry, 1977, in the press.$ This acid had been named cuneifolic acid before its structurewas established (M.U. S. Sultanbawa, J . Nut. Sci. Council of S r iLanka, 1973, 1, 12311 (a) R. Somanathan and M. U. S. Sultanbawa, J.C.S. PerkinI , 1972, 1935; ( b ) M. Dahanayake, I. Kitagawa, R. Somanathan,and M. U. S. Sultanbawa, ibid., 1974, 2510; ( c ) R. Somanathanand M. U. S. Sultanbawa, ibid., 1974, 2515; ( d ) S. P. Gunasekeraand M. U. S. Sultanbawa, ibid., 1975, 2215.3 J. L. Courtney and R. M. Gascoigne, J . Chem. SOC., 1956,A. J. Kostermans, personal communication.2115.methane the n.m.r. spectrum of which was identicalwith that of methyl isoapetalate (4b).8 From the abovedata, the compound was identified as isoapetalic acid(4a) and the structure was confirmed by comparisonTABLE 1U.V.spectra [hlllB,. (EtOH)/nm (log E)]Acidn1.p. 225-227" 268 276 301 314 368Apetalic acid * (6b) 268 301 315 368Blancoicacid t (6a) 267 275 300 312 365(4.49) (t::) (4.01) (4.03) (3.77)(4.49) (4.53) (4.40) (4.03) (3.37)(4.60) (4.62) (4.05) (4.07) (3.33)(i.r. data) of the methyl ester with authentic methyl iso-apetalate 8 (4b). This ester had been reported previouslyas a gum,8 the isolation of free isoapetalic acid $ is nowreported here.(3a), oxidation of isoapetalicacid (4a) with nitric acid gave (+)-(R)-n-propylsuc-cinic acid lo showing that the configuration at the asym-* Ref. 15. t Ref. 9.As with blancoic acidn d( 3 1 ( L 1a ; R = M ~ [ C H ~ I Lb ; R = P r "a; R = Hb; R = Memetric centre in the side chain was similar to that inblancoic acid.S. Burrowsand J.C. E. Simpson, J . Chem. Soc., 1938, 2042.H. Budzikiewicz, J . M. Wilson, and C. Djerassi, J . Amer.Chem. Soc., 1963, 85, 3688.R. T. Alpin, H. R. Arthur, and W. H. Hui, J. Chem. Soc. ( C ) ,1966, 1251.S. S. Selliah, M.Sc. Thesis, University of Ceylon, 1972; S. S.Selliah and M. U. S. Sultanbawa, Proc. CeyZon Assoc. Adv. Sci.,1972, 28, 120.E. Guerreiro, G. Kunesh, and J . Polonsky, Phytochemistry,1971, 10, 2139.@ G. H. Stout and K. D. Sears, J . Org. Chem., 1966, 33, 4185.lo (a) ' Dictionary of Organic Compounds,' vol. 5, Eyre andSpottiswoode, London, 1965, p. 2798; ( b ) A. Fredga, J. P.Jennings, W. Klyne, P. M. Scopes, B.Sjoberg, and S. Sjoberg,J . Chem. Soc., 1965, 39281506 J.C.S. Perkin ITimber extractives. Hot chloroform extraction of thetimber gave a yellow pigment, m.p. 280-281" and a gum.The pigment gave a green colouration with iron(II1)chloride and had U.V. maxima at 235 (log E 4.49), 246(4.42), 300 (4.26), and 359 nm (3.60) and strong i.r.absorption at 1650 and 3 400 cm-1, indicative of axanthone structure. The n.m.r. spectrum showedsignals at T 4.69 (1 H, t), 6.61 (2 H, d), 8.20 (3 H, s), and8.33 (3 H, s) indicating the presence of an isopentenylside chain. The n.m.r. splitting pattern of the aromaticproton signals resembled those of 1,2,3,5-tetrasubstitutedxanthone systems such as l-hydroxy-2,3,5-trimethoxy-xanthone l1 (5) or l-hydroxy-3,5-dimethoxy-2-(3-methyl-but-2-eny1)xanthone (6b), having a low field quartet atat T 2.33 (H-8), a multiplet at T 2.70 (H-6 and -7), and asinglet at T 3.42.There were no methoxy-signals.Methylation of the xanthone with diazomethane gave adimethyl ether, identical with authentic l-hydroxy-3,5-dimethoxy-2- (3-met h ylbut -2-en yl) xanthone (6b) ; thisOR'OMe( 5 ) (61OH( 7 )established that the pigment was lJ3,5-trihydroxy-2-(3-methylbut -2-enyl) xanthone (6a).Treatment of the pigment (6a) with formic acid12 atroom temperature gave mainly the cyclised derivative(7), as shown by its n.m.r. spectrum.13The benzene-soluble fraction of the chloroform extractwas separated by washing with borax and sodiumcarbonate solutions and chromatography on silica gel intop-sitosterol, 1,5-dihydroxy-6-(3-methylbut-2-enyl)xan-thone (8) (guanandin),14 1,7-dihydroxyxanthone (9)(euxanthone), 6-deoxyjacareubin ( 10a),15 scriblitifolicacid (1 1) , l 6 and 1,6-dihydroxy-5-methoxyxanthone(12a) ,17 identical with authentic samples.The benzene-insoluble residue on similar separationgave jacareubin l8 (lob), identical with an authenticsample.l1 G.H. Stout and W. J. Balkenhol, Tetrahedron, 1969, 25,1947.l2 E. D. Burling, A. Jefferson, and F. Scheinmann, Tetrahedron,1965,21, 2653.13 P. J. Owen and F. Scheinmann, J.C.S. Perkin I , 1974, 1018;B. Jackson, H. D. Locksley, and F. Scheinmann, J . Chetn. SOC.( C ) , 1967, 2500.l4 D. de Barros Correa, 0. R. Gottlieb, and M. Taviera Magal-haes, Anais Acad.brasil. Cienc., 1966, 38, 296.Calophyllum soulattri Burm. f .-Bark extractives.Cold light petroleum extraction gave a white solid, m.p.201-202", C25H8405, A,,,. (EtOH) 233 (log E 3.43), 287( 8 )OH(10 1a;R = Hb ; R = O HOMe(12)b ; R = HCO,H (11 1 a ; R = O H(3.37), and 335 nm (3.08) vlnax. 2 479 (OH), 1 705 (ctp-un-saturated %lactone), and 760 and 700 cm-l (monosubsti-tuted benzene ring). These spectral data suggested thatthe compound was a new coumarin, and it was namedsoulattrolide. The mass spectrum showed the intense(13 1a; R=H , P=OHb ; R = Oc ; R=H ,g=OAcd;R=H,P=OMepeaks characteristic of a coumarin of the inophyllolideseries: 19-21 M - CH, (m/e 389), M - H,O (386),M - H,O - CH, (371), and M - 15 - 56 (333).Thesefragments suggested the presence of a secondary hy-l5 T. R. Govindachari, D. Prakash, and N. Viswanathan,Tetrahedron, 1968, 24, 641 1.l6 B. Jackson, H. D. Locklsey, and I?. Scheinmann, J . Chew.SOC. (C), 1967, 785.17 B. Jackson, H. D. Locksley, 1. Moore, and F. Scheinmann,J. Chem. SOC. ( C ) , 1968, 2579.18 F. E. King, J. T. King, and L. C. Manning, J . Chem. SOC.,1953, 3932; 1957, 563.19 J . Polonsky and R. Toubiana, Compt. vend., 1956, 242, 2877.2o S. K. Nigam, C. R. Mitra, G. Kunesch, B. C. Das, and J.Polonsky, Tetrahedron Letters, 1967, 26331977 1507droxy-group and gem-dimethyl system of a chromen ringin an inophyllolide skeleton.The n.m.r. spectrum of soulattrolide (13a) resembledthe specific rotation 1-45.9 (CHCl,)] suggested that(13b) was the enantiomer of (+)-inophyllolide (inophyl-lum C), whose specific rotation has been reported to be+13" (natural product) or +54" (oxidation product ofenantiomers the natural alcohol, inophyllum B) .22 This discrepancyin rotation has been ascribed to the naturally occurringketone being partially racemised.22That the methyl groups at C-10 and -11 were trans- wasevidmt from the values of 10.8 and 10 Hz for Jlo,ll foro$o (13bl r /,\+'(1 6)Cr0,-C5H 5N T(1 3a 1 (18) (15)f l y f lena ntiomers\epimersSCHEMEthose of inophyllum A (14) and inophyllum B (15), twoof five piscidal constituents 21*22 isolated from the leavesof C.iutophyllum L. (Table 2). Oxidation of soulattrolidethe oxidation product (13b) and the alcohol- (13a),respectively, in agreement with values recorded for sucht r a n s - c ~ u p l i n g .~ ~ ~ ~ ~ Therefore the ketone (13b) can bedesignated (-)-tram-inophyllolide and the alcohol soul-attrolide is a diastereoisomer of inophyllum B (15)having a cis-configuration for the C-11 and -12 protons.This is confirmed by J11,12 (3.2 Hz) for soulattrolide ( c j .7.4 Hz for inophyllum B 22924). (-)-trans-Inophyllolide(13b) on reduction with sodium borohydride gave soul-attrolide (13a) (identical with natural product) and itsepimer (18). The latter had the same u.v., i.r., and n.m.r.spectra as inophyllum B, with a negative specific rot-ation ([a], -35.3). It is therefore the enantiomer ofinophyllum B (see Scheme).Soulattrolide (13a) also gave a methyl ether (13d)without change of configuration at C-12 and a dehyd-3-H4-Ph6,6-Me27-H8-H10-H1 l-H10-Me1 l-Me12-HTABLE 2N.ni.r.data [T values (CDCl,), J in Hz] *Oxidation product( 13b)lnophyllum CZ2 (16) of soulattrolide Inophyllym A22 (14) Soulattrolide (Ma) Inophylluni Bjra (15) { ( + )-trans-inophyllo- ( - )-trans-inophyllo- (+ )-cis-dihydroino- ( -.)-trans-dihydro- (+);trans-dihydro-3.96 (1 H, s) 3.97 (1 H, s) 4.04 (1 H, s) 4.06 (1 H, s) 4.04 (1 H, s)2.7 (5 H , m) 2.7 (5 H, m) 2.7 (5 H, m)9.02, 9.05 (6 H, s) 9.06 (6 H, s) 9.07, 9.09 (6 H, s)4.58 (1 H, d, J 10) 4.63 (1 H, d, J 10) 4.63 (1 H, d, J 10)3.44 (1 H, d, J 10) 3.45 (1 H, d, J 10) 3.47 (1 H, d, J 10)5.68 (1 H, m, J 6.6, 5.57 (1 H, m, J 7.0, 6.03 (1 H, m, J 6.8,11.5) 10.8) 3.3) 10.0) 8.9)7.41 (1 H, m, J 7.2, 7.73 (1 H, m) 7.97 (1 H, m, J 7.0,11.5) 10.8) 10.0) 8.9, 7.4)8.44 ( 3 H, d, J 6.6) 8.57 (3 H, d, J 7.0) 8.53 (3 H, d, J 6.8)8.76 (3 H, d, J 7.2) 8.83 (3 H, d, J 7.2) 8.83 (3 H, d, J 7.0)4.83 (1 H, d, J 5.4) 5.21 (1 H, d, J 7.4)1 lide 1 { lide 1 { phyllolide t 1 { inophyllolide t 1 { inophyllolide2.7 (5 H, m)9.02 ( 6H, s)4.59 (1 H, d, J 10)3.46 (1 H, d, J 10)5.69 (1 H, m, J 6.4,7.42 (1 H, ni, J 7.2,8.46 (3 H, d, J 6.4) *8.76 (3 H, d, J 7.2)2.7 (5 H, m)9.07 (6 H, s)4.65 (1 H, d, J 10)3.47 (1 H, d, J 10)5.69 (1 H, ni, J 7.0,8.22 (1 H, m, J 3.2,8.56 (3 H, d, J 7.0)8.84 (3 H, d, J 7.2)4.96 (1 H, d, J 3.2)Dihydro refers to C(12):O reduction to C(12)H(OH). * (14)-(16) a t 60 MHz; (13a and b) at 100 MHz.(13a) with chromic acid-pyridine gave a ketone (13b)(vlmx.1690 cm-l) whose n.m.r. spectrum was identicalwith that of inophyllum C(16) 22 (Table 2) isolated fromthe leaf of C. inophyllum L. Inophyllum C (16) is the(+)-form of (-f )-inophyllolide isolated from the nuts ofC. znophyllum L.23 The i.r. spectra of the ketone(13b) and (-J-)-inophyllolide were identical. However21 K. Kawazu, H. Ohigashi, and T. Mitzui, Tetrahedron Letters,22 K. Kawazu, H. Ohigashi, M. Takanashi, and T. Mitzui,1968, 2383.Bull. Inst. Chem. Res. Kyoto Univ., 1972, 50, 160.ration product (17) in keeping with the assignmentsgiven in the Scheme. Therefore soulattrolide is (-)-10,ll -dihydro- 12 p-hydroxy-6,6,1 Oa, 1 1 p-te tramet hyl-4-pheny1-2H,6H,lOH-benzo[l,2-b ; 3,4-b' ; 5,6-b"] tripyran-2-one.The remaining gum from the light petroleum extractwas separated on a column of silica gel to give taraxer-taraxer01,~ p-sitosterol, and more soulattrolide(13a), identical with authentic samples.From the light petroleum andbenzene extracts of the timber, the following compoundswere isolated by silica gel chromatography : 6-deoxy-jacreubin (6), 1,6-dihydroxy-5-methoxyxanthone (12a),23 J.Polonsky, Bull. SOC. chim. France, 1957, 1079; 1958, 929.24 J . W. Clark-Lewis, L. M. Jackmann, and L. R. Williams,J . Chem. Soc., 1962, 3858.25 L. M. Jackman and S. Sternhell, 'Applications of NuclearMagnetic Resonance Spectroscopy in Organic Chemistry, 'Pergamon, London, 1969, p. 238.Timber extractives1508 J.C.S.Perkin I1-hydroxy-5-methoxyxanthone (12b), p-sitosterol, 1,3,5-trihydroxy-2-(3-methylbut-2-enyl)xanthone (6a), and 1,7-dihydroxyxanthone (6), identical with authentic samples.l-Hydroxy-5-methoxyxanthone (12b) is a new naturalproduct.In Table 3 the metabolites isolated from these twoplants are compared: products of both 1,5- and 1,7-oxygenation patterns are observed in each species.More prenylated products have been isolated from C.cuneifolium Thw. than from C. soulattri Burm f . Theproducts differ too in the presence of a resin solid (iso-apetalic acid) in the former and a coumarin (soul-attrolide) in the latter.The presence of soulattrolide in large quantities in thebark of C.soulattri Burm. f. is of special significance, assuch 4-phenylcoumarins have been reported from theleaf and nut of C . inophyllum L. ' Jacareubin has been isolated from 16 out of 26 CaZo-phyllum species 26 that have been studied to date, and isconsidered to be a taxonomic marker for this genus.TABLE 3Amounts of compounds isolated (% based on dryweight)C. cuneifolium Thw. C. soulattri Burm. fA ----Calabaxanthone (1)6-Deoxyjacareubin1,6-Dihydroxy-5-(10a)(124(9)methoxyxanthone(buchanoxanthone)Soulattrolide (13a)1,7-DihydroxyxanthoneFriedelinGuanandin (8)l-Hydroxy-5-methoxy-xanthone (12b)Isoapetalic acid (4a)Jacareubin (10)l13,5-Trihydroxy-2-(3-methylbut-2-eny1)xanthone (6a)Scriblitifolic acid (1 1)p-Simiarenolp-SitosterolTaraxerolTaraxeroneTrapezifolixanthone (2)Bark Timber0.080.020.0050.030.120.140.080.060.050.160.030.06 0.020.060.07Bark0.330.0020.0020.002I Timber0.020.030.010.050.040.008The failure to isolate jacareubin from C.soulattri Burm. f.may be due to the presence of a powerful dehydroxy-1atin.g enzyme. This view seems to be substantiated byt.he presence of (a) 1,3,5-trihydroxy-2- (3-met hyl but -2-enyl)xanthone, which could be derived from 1,3,5,6-t etrahydroxy-2- (3-met hylbut-2-enyl) xant hone, the j ac-areubin precursor, by removal of the 6-OH ; ( b ) 6-deoxy-jacareubin, which could be derived from jacareubinitself or from its own precursor (6a) that has been isol-ated ; (c) l-hydroxy-5-methoxyxanthone (12b) which isreported for the first time from a plant.This may havearisen by removal of the 6-OH from 1,6-dihydroxy-5-26 S. P. Gunsasekera, Ph.D. Thesis, University of Sri Lanka,Peradeniya Campus, 1976.methoxyxanthone (l2a), which is present to a smallerextent in this plant than (12b).EXPERIMENTALU.V. spectra (solvent ethanol) were recorded with aUnicam SP 8000B spectrophotometer, and i.r. spectra witha Perkin-Elmer 257 spectrophotometer. N.m.r. and massspectral data were obtained from the instruments a t theUniversities of Shefield and Aberdeen and the TropicalProducts Institute. Rotations were determined with aBellingham and Stanley polanmeter. Analytical andpreparative t.1.c. were carried out with silica gel G (Merck).Column chromatography was carried out by use of silica gel(Merck; 30-70 mesh).M.p.s were determined with aKofler hot-stage apparatus. All RF values refer t o t.1.c.(thickness 0.25 mm). Elemental analyses were carried outa t the CSIRO Microanalytical Service, Melbourne, Australia.Calophyllum cuneifolium Thw.Calofihyllum cunei folium Thw. was obtained from Passara(Uva Province). Bark and timber extractives were ob-tained separately as in earlier parts of this series.Bark Extractives.-The bark (4.5 kg) was extracted withlight petroleum (b.p. 60-80 "C) to give a brown gum (135 g,3.0%). This gum (13 g) was dissolved in diethyl ether(1.5 1) and washed with cold 10% sodium carbonate solution.The ether layer gave a gum (A) (8.0 g, 0.18y0).Acidifi-cation of the sodium carbonate solution, extraction withether, and the usual work-up gave an acidic material (B)(4 g, 0.09%).Friedelin and taraxerol. The gum (A) (4 g) was separatedon a silica gel column (150 g) . Elution with light petroleum-benzene (1 : 4) gave friedelin (0.100 g), m.p. 264" (fromethanol), -21" (in CHCl,) {lit.,,, m.p. 264", [a], -22.1"(in CHCl,)}. Elution with benzene gave taraxerol (0.080 g),m.p. 279-280" (from ethanol), +5" (in CHCl,) (lit.,*m.p. 279-282", [a]= + 3"). Both compounds were identicalwith authentic samples (mixed m.p., i.r. spectra, and t.1.c.).Furtherelution of the foregoing column with benzene gave calabax-anthone (0.100 g), m.p. 172" (from ethanol) (lit.,lU 172");acetate, m.p.147" (1it.,lu 147"). Further elution with ben-zene-chloroform (4 : 1) gave trapezifolixanthone (0.089 g),yellow crystals (from benzene), m.p. 171-172" (lit.,lC 172").The compounds were identical with authentic samples(mixed m.p., i.r. 'spectra, and t.1.c.).Isoapetalic acid (4a). The acidic gum (B) (4 g) waschromatographed on silica gel (75 g). Elution with chloro-form gave isoapetalic acid (4a), m.p. 225-227", + 18.2"(CHCI,), RiF 0.5 (in CHC1,) (Found: C, 68.0; H, 7.4%;M+, 388. C,,H,806 requires C, 68.0; H, 7.25%; M , 388);A,,,. (EtOH) in Table 1; v,,,. (Nujol) 2 930, 1 703, 1 648,1 623, and 1 577 cm-l; T (CDCl,; 100 MHz) - 1.44 (1 H, s,5.80 (1 H, m, 8-H), 6.28 (1 H, m, P-H), 7.25 (2 H, m, a-H),7.32 (1 H, m, 7-H), 8.50 (3 H, d, J 7 Hz, 8-CH3), 8.54br (4 H,CH,*CH,.CH,), 8.58 (6 H, s, CMe,), 8.82 (3 H, d, J 7 Hz,7-CH3), and 9.13 (3 H, t, J 7 Hz, CH,-CH,.CH,); m/e 388,(17%), 373(100), 355(7), 345(5), 329(10), 313(10), 301(5),299(5), 272(8), 231(3), 229(3), and 95(14).Isoapetalic acid (0.100 g)in ether ( 5 ml) was treated with an excess of diazomethane.The usual work-up and slow evaporation of the solutiongave pale yellow crystals of methyl isoapetalate (4b) (0.55g), m.p.82-83" (from methanol), [a]=],"' -69,l" (in CHCl,)Calabaxanthone (1) and trapezifolixanthone (2).&OH), 3.43 (1 H, d, J ~OHZ, 4-H), 4.43(1 H, d, JlOHz, 3-H),Methylation of isoapetalic acid1977 1509{lit.,8 [a], --68.3" (in CHCl,)), M ' 402, H , 0.80 (CHCl,), hI,,ax.(EtOH) 228 (log E 4.01), 267 (4.42), 274 (4.63), 300 (4.02),311 (4.07), and 362 nm (3.62); vmx. (Nujol) 2 927, 1732,1647, 1627, and 1577 cm-l; T (CDC1,; 100 MHz) -2.40J 10 Hz, 3-H), 5.88 (1 H, m, J8,7 12 Hz, 8-H), 6.27 (1 H, ni,p-H), 6.45 (3 H, s, CO,Me), 7.28 (2 H, dd, J 7 and 1 Hz,a-H), 7.5 (1 H, m, 7-H), 8.52 (3 H, d, J 6.5 Hz, 8-Me), 8.57and 8.59 (6 H, two s, 2-Me2), 8.81 (3 H, d, J 7 Hz, 7-Me), and9.15 (3 H, t, J 7 Hz, CH,.CH,Me) ; m/e 402( 16y0), 387( loo),371(3), 359(4), 329(10), 327(3), 299(2), 285(4), 273(3), 271(5),257(3), 243(1), 231(2), 229(3), 189(1), 149(10), and 87(4), iden-tical with an authentic sample (i.r.spectra).Isoapetalic acid (4.8 g) in50% nitric acid (50 ml) was left at room temperature for1 day and then refluxed for 5 days on a water-bath. Theproduct was cooled, excess of sodium hydrogen sulphite wasadded, and the mixture was extracted with diethyl ether.The extract was dried (Na,SO,) and evaporated to leave anoil (0.170 g).The oil was treated with light petroleum (10ml) and kept a t 0 "C for 4 weeks to give white crystals of(+)-n-propylsuccinic acid (0.110 g), m.p. 94-95', [a],,'+11.1" (in CHCl,) (lit.,loa 93.9" [a], +9.6") (Found: C,52.0; H, 7.4. Calc. for C,H,,O,: C, 51.85; H, 7.45%).p-Sitosterol. Elution of the foregoing column withchloroform afforded p-sitosterol (0.050 g), m.p. 135' (fromethanol) (lit. ,z7 136---137"), identical with an authenticsample (mixed m.p., i.r. spectra, and t.1.c.).Elution of the column with benzene-chloroform (1 : 1) gave simiaren-3P-01 (0.120 g), whitecubes (from methanol), m.p.209O, +48" (in CHC1,)(lit.,6 m.p. 210°, [aID +50"), 0.5 (chloroform-benzene,1 : 4), M+ 426; v , , ~ ~ . (KBr) 1 650 and 3 470 cm-l; acetate,m.p. 209", [aID28 + 68" (in CHC1,) (lit.,8 m.p. 209', [a], + 73.9"),RF 0.5 (benzene). On oxidation with chromic acid-pyridine,it gave simiarenone, m.p. 206", [aID2'j +25" (lit.,6 m.p.207--2@8', [a], + 24'), RF 0.5 (light petroleum-benzene,1 : 3). The three compounds were identical with authenticsamples.Timber Extractives.-The timber (10.0 kg) on extractionwith hot chloroform gave a yellow solid (C) (2.5 g, 0.025%)and a gum (I)) (145 g, 1.45%). Hot benzene extraction ofthe gum (D) (60 g) left a residue (F), and removal of benzenefrom the solution gave a gum (E) (20 g, 0.58%).This gum(5 g) was dissolved in diethyl ether (500 ml) and washed with10% cold aqueous borax and 10% sodium carbonate solu-tion, successively.1,3,5-Trihydroxy-2-( 3-methylbut-2-enyZ)xanthone (6a). Theyellow solid (C) (0.500 g) on repeated crystallisation fromacetone gave 1,3,5-trihydroxy-2-( 3-methylbut-2-enyl)xanthone(0.300 g) as a pale yellow solid, m.p. 280-281", RiF 0.5(chloroform-methanol, 40: 1) (Found: C, 68.9; H, 5.15.CI8Hl6O5 requires C, 69.0; H, 5.15%) ; Lax. (EtOH) 235sh(log E 4.49), 246 (4.42), 300 (4.26), and 359 nm (3.60) ; vrnaX.(KBr) 855, 940, 1068, 1098, 1125, 1170, 1252, 1290,1310, 1335, 1345, 1380, 1405, 1465, 1475, 1505,1580, 1620, 1650, and 3 400 cm-l; T [(CD,),CO; 100MHz] 2.33 (1 H, q, J 4 and 6.5 Hz, 8-H), 2.70 (2 H, m, 7- and6-H), 3.42 (1 H, s, 4-H), 4.69 (1 H, t, J 7 Hz, vinylH), 6.61(2 H, d, J 9 Hz, methylene H), and 8.20 and 8.33 (6 H, twos, CMe,).Compound ( 6 4 (0.100 g) in ether was treated with anexcess of diazornethane ; the usual work-up gave l-hydroxy-3,5-dimethoxy-2-( 3-niethylbut-2-eny1)xanthone (0.075 g),(1 H, S, 5-OH), 3.40 (1 H, d, J 10 Hz, 4-H), 4.55 (1 H, d,Oxidation of isoapetalic acid.Simiaren-3P-nl.The ether layer gave a gum (G).27 Ref.10a. p. 2902.1n.p. 167-168" (lit.,13 167-170"), RF 0.5 (CHCl,), identicalwith an authentic sample (mixed m.p., i.r. spectra, and t.1.c.).The xanthone (0.040 g)was treated with formic acid ( 5 mi) at 27 "C for 15 min. Theusual work-up, followed by recrystallisation from ethanol,gave 3,4-dihydro-5,8-dihydroxy-2,2-dimethylfiyrano[3,2-a]-xanthen-l2(2H)-one (7), m.p.217-218", RF 0.5 (benzene-chloroform, 1 : 1) (Found: C, 69.2; H, 5.15. Cl,H160,requires C, 69.2; H, 5.1%), Amx. (EtOH) 243 (log E 5.48),255(5.42), 272sh (4.24), 320 (4.20). and 350 nm (3.66);T [(CD,),CO; 100 MHz] 2.35 (1 H, q, J 3 and 6 Hz, 8-H),2.74 (2 H, m, 7- and 6-H), 3.64 (1 H, s, 4-H), 7.30 and 8.11(4 H, 2 t, J 7 Hz, chroman CH,*CH,), and 8.52 (6 H, s,chroman CMe,) .Guanandin (8) and 6-deoxyjacareubin ( 10a). The gum(G) was chromatographed on silica gel column (75 g).Elution with benzene afforded yellow plates (from benzene)of 1,5-dihydroxy-6-( 3-methylbut-2-eny1)xanthone (8) (guan-andin) (0.060 g), m.p. 206" (lit.,14 206-208"), RE' 0.83(chloroform-methanol, 40 : 1).Further elution of the column with benzene-chloroform(4 : 1) gave yellowish plates (from benzene) of 6-deoxyjacare-ubin (loa) (0.080 g), m.p.208-210" (lit.,13 211--213'), R%,0.45 (chloroform-methanol 40 : 1). Both compounds wereidentical with authentic samples (mixed m.p., i.r. spectra,and t.1.c.).p-Sitosterol. Elution of the column with chloroformafforded p-sitosterol (0.080 g), m.p. 135-136".1,7-Dihydroxyxanthone (9). Elution of the column withchloroform-methanol (99 : 1) afforded yellow needles (fromacetone) of 1,7-dihydroxyxanthone (euxanthone), m.p. 238"(lit.,28 238-240"), RF 0.7 (chloroform-acetic acid, 92 : 8),identical with an authentic sample (mixed m.p., i.r. spectra,and t.1.c.).Acidification of the borax wash-ings and the usual work-up gave a brown solid (H) (0.400 g),which was chromatographed on silica gel (30 g).Elutionwith chloroform-benzene (1 : 1) afforded yellow needles(from benzene) of scriblitifolic acid (0.060 g), m.p. 164-165"(1it.,l6 164-167"), RF 0.25 (chloroform-methanol, 40 : l),identical with an authentic sample (mixed map., i.r. spectra,and t.1.c.).(buchanoxanthone)( 12a). Acidification of the sodium carbonate washingsand the usual work-up gave a gum (I) (1 g), which waschromatographed on a silica gel column. Elution withbenzene afforded pale yellow needles (from acetone) of 1,6-dihydroxy-5-methoxyxanthone ( 12a) (buchanoxanthone)(0.030 g), m.p. 243-245" (lit.,17 243-246"), RF 0.8 (chloro-form-methanol, 40 : l), identical with an authentic sample(mixed m.p., i.r.spectra, and t.1.c.).Jacareubin (lob). The residue (F) of the chloroformextract (4 g) was chromatographed on a silica gel column.Elution with chloroform-methanol (75 : 1) gave brightyellow needles (from ethanol-water) of jacareubin (lob),n1.p. 253-254" (1it.,l8 254-256"), RF 0.5 (chloroform-acetic acid, 92 : 8), identical with an authentic sample(mixed m.p., i.r. spectra, and t.1.c.).Calophyllum soulattri Burm. f ,C. soulattri Burm. f. was obtained from Morapitiya,Kalutara District. Bark and timber extractives wereobtained separately as in earlier parts of this series.Kao, and N. Muthukumaraswamy, Tetrahedron, 1967, $33, 243.Cyclisation of the xanthone (6a).Scriblitifolic acid ( 11).1,6 - D ihy droxy - 5- met h oxyxant hone28 T.R. Govindachari, B. R. Pai, P. S. Subramaniam, U. K1510 J.C.S. Perkin IBark Extractives.-Powdered bark (6.0 kg) was extractedwith cold light petroleum to give a white solid (J) (26 g,0.44%) and a gum (K) (110 g, 1.83%).Repeated crystallisation of the whitesolid (J) from methanol gave soulattrolide, white needles(20 g, 0.33%) m.p. 201-202", -29.6" (in CHCl,),RF 0.52 (ethyl acetate-chloroform, 1 : 9) (Found: C, 74.3;H, 6.15% ; M+, 404. CZ5H24O5 requires C, 74.25; H, 6.0% ;M , 404) (no change in U.V. pattern in the presence of AlCl,,NaOAc-H,BO,); vmx. (Nujol) 3 479, 2 930, 2 860, 1 705,1640, 1590, 1565, 1470, 1415, 1372, 1349, 1310, 1255,1230, 1 200, 1 180, 1 150, 1 140, 1 130, 1 115, 1062, 1022,995, 965, 930, 880, 850, 795, 772, 760, 710, and 700 cni-l;n.m.r.data in Table 2; m/e 404(20%), 389(62), 386(46),371(100), 333(46), 317(3), 305(3), 202(3), 193(4), 178(16),164(5), 115(5), 105(5), 78(6), and 42(6).Soulattrolide (0.050 g) inpyridine (3 ml) was treated with chromium trioxide (0.020 g)and left at room temperature for 2 days. The usual work-up and removal of solvent gave a waxy solid mixture ofthree compounds (t.1.c.). The mixture was separated on asilica gel plate with methanol-chloroform (1 : 19) into(-)-trans-ircofihyllolide (13b) (trans-l0,l l-dihydro-6,6,10,11-tetramethyl-4-fihercyl-2H,6H1 12H-benzo[ 1,2-b; 3,2-b'; 5,6-b"]tripyran-2,12-dione} (0.030 g), m.p. 187-190", -45.9"(in CHCl,) {lit.,21 m.p.188-199", + 13" and + 54" forenantiomer (in CHCl,) } RF 0.63 (ethyl acetate-chloroform,1 : 9); M+ 402; (EtOH) 257sh (log E 4.46), 266 (4.49),and 302 nm (4.39); v,,,, (Nujol) 2 930, 2 860, 1 740, 1 690,1 640, 1 600, 1 580, 1 555, 1 405, 1 380, 1 340, 1 315, 1 240,1 195, 1 190, 1 145, 1 130, 1 089, 1 000, 955, 920, 880, 860,835, 775, 735, and 705 cm-l; n.m.r. data in Table 2; m/e402(33y0), 387(100), 353(2), 346(3), 331(70), 263(3), 229(2),219(2), 189(2), 105(2), and 77(2), identical (i.r. data) withauthentic ( f )-trans-inophyllolide.Soulattrolide (0.035 g)was acetylated with acetic anhydride-pyridine (1 : 1) (4 ml) .The acetate (13c) (0.025 g) had m.p. 180-181" (from lightpetroleum), [a],27 -125" (in CHCl,), vnlax. (Nujol) 1 750,1730, 765, and 710 cm-l (Found: C, 72.35; HI 5.85.C,,H,,O, requires C, 72.65; H, 5.85%); T (CDC1,; 100MHz) 2.7 (5H, m, Ph), 3.46 (1 H, d, J lOHz, 8-H), 3.56 (1 H,7-H),5.84(lH,m,10-H),7.88(3H,s,12-OAc),8.04(1H,m,ll-CH,), and 9.04 (6 H, s, 6-Me2).Reductzoa of ( -)"trans-z~~~~~ZZoZz~e (13b).(-)-trans-Inophyllolide (0.100 g) in methanol (20 ml) was treated withsodium borohydride (0.100 g) in methanol (10 ml). Themixture was stirred for 2 h, the excess of hydride wasdestroyed with water and the product was extracted withether. The gum obtained on evaporation was separatedon a silica gel plate with methanol-chloroform (2 : 98) intotwo compounds. The more polar compound on crystallis-ation from light petroleum yielded soulattrolide (13a)(0.016 g), m.p. 201-202", identical with the natural com-pound (mixed m.p., [a],, i.r., and t.1.c.).The less polarfraction was the enantiomer (18) of inophyllum B (15) 22 andwas not crystallised; yield 0.032 g, -35.3" (in CHC1,)(lit.,22 [a], +36" for enantiomer), RF 0.60 (ethyl acetate-chloroform, 1 : 9), Amx. (EtOH) 233 (log E 3.43), 278sh(3.36), 285 (3.41), and 335 nm (3.08) ; vmX. (KBr) 865, 968,1058, 1 140, 1370, 1587, 1645, and 1 715 cm-l; T (CDCl,;60 MHz) 2.7 (5 H, m, Ph), 3.47 (1 H, d, J 10 Hz, 8-H),Soulattrolide (13a).Oxidation of souZattroZide (13a).Acetylation of soulattrolide (13a).d, J 4.0 Hz, 12-H), 4.04 (1 HI S, 3-H), 4.63 (1 HI d, J 10 Hz,Il-H), 8.54 (3 H, d, J 6.2 Hz, 10-CH,), 8.92 (3 H, d , J 10 Hz,4.05 (1 H, S, 3-H), 4.64 (1 N, d, J 10 Hz, 7-H), 5.21 ( 1 H, d,J 7.4 Hz, 12-H), 6.0 (1 H, ni, 10-H), 8.0 (1 H, m, 11-H), 8.53and 9.05 and 9.10 (6 H, two s, 6-Me2); m/e 404 (lo%),389 (36), 371 (lo), 333 (22), 317 (3), 305 (7), 178 (lo), 149(loo), 115 (7), 105 ( l l ) , 85 (44), and 83 (62).The product (18)(0.020 g) was oxidised with chromic oxide (0.030 g) inpyridine (5 ml) for 2 days.The usual work-up and crystal-lisation from light petroleum gave material (0.016 g), m.p.188-189', [aID2' -48.1" (in CHCl,), identical with (-)-trans-inophyllolide (13b) (mixed m.p., i.r,, and t.1.c.).Soulattrolide (0.100 g)and toluene-p-sulphonic acid (0.010 g) in dry benzene (10ml) were refluxed for 30 min and the product was washedwith water. Removal of benzene and crystallisation fromlight petroleum yielded pale yellow crystals of the dehy-dration product (17) (0.086 g), m.p.197-198" (lit.,22 198"for epimer), [a], +43.3' (in CHCl,) (lit.,22 [a], -42" forepimer), RF 0.21 (benzene); A,,,. (EtOH) 251 (log E 4.28),290 (4.25), 301sh (4.14), 315 (4.07), and 350 nm (3.83);v,,,. (Nujol) 1650 and 1718 cm-l; T (CDC1,; 60 MHz)2.7 (5 H, m, Ph), 3.30 (1 H, s, 12-H), 3.46 (1 H, d, J 10 Hz,( 1 H, q, J 6.8 Hz, 10-H), 8.12 (3 H, s, ll-CH,), 8.60 (3 H,d, J 6.8 Hz, 10-CH,), and 9.07 (6 H, s, 6-Me2); m/e 386r44%), 371 (loo), 357 ( l ) , 343 (2), 193 (3), 178 (5), and164 (3).To soulattrolide (0.100g) in methanol (2 ml) was added one drop of 2~-hydrochloricacid and the solution was refluxed for 4 min. The productwas diluted with water and extracted with ether.Re-moval of the solvent gave an oil which was separated on asilica gel plate with benzene-chloroform ( 1 : 3). Themethyl ether (13d) was a gum (0.036 g), -60.0' (inCHCl,), R p 0.16 (chloroform-benzene, 1 : l), A,. (EtOH)233 (log E 4.25), 278sh (4.21), 287 (4.27), and 337 nm (4.08) ;v,,,. (Nujol) 1650 and 1725 cm-l; 5 (CDCl,; 60 MHz)2.7 (5 H, m, Ph), 3.47 (1 H, d, J 10 Hz, 8-H), 4.05 (1 H, s,12-H), 5.8 (1 H, m, 10-H), 6.36 (3 H, s, 12-OMe), 8.22 (1 H,m, 11-H), 8.60 (3 H, d, J 7 Hz, 10-CH,), 8.84 (3 H, d, J 7.2Hz, ll-CH,), and 9.07 (6 H, s, &Me,) ; m/e 418, 403, 387,371, 348, 347, 193, 178, 149 (out of scale for intensitydetermination).Taraxerone. The gum (K) (2.4 g) was chromatographedon a column of silica gel (75 g) .Elution with light petrol-eum-benzene (4 : 6) gave taraxerone (0.025 g), m.p. 238-240" (from chloroform) (lit.,4 240-241'), [a],27 + 15" (inCHC1,) (lit.,4 [a], + 12.0'), identical with an authenticsample (mixed m.p., i.r. spectra, and t.1.c.).Elution of the above columnwith benzene gave taraxerol (0.025 g), n1.p. 276-278"(from chloroform-acetone) , [aJD27 + 5", and p-sitosterol(0.028 g), m.p. 136-137". Elution with benzene-chloro-form (3 : 1) then gave more soulattrolide (0.015 g).Timber Extractives.-Powdered timber (8.5 kg) wasextracted with cold light petroleum to give a yellow solid(L) (5.0 g, 0.05y0) and a gum (M) (12.0 g, 0.14%). Similarlythe benzene extract gave a yellowish brown solid (N)(12.08 g, 0.14%) and a gum (0) (10 g, 0.11%).6-Deoxyjacareubin ( 10a) and 1,6-dihydroxy-5-rnethoxy-xanttzone (l2a).The solid (L) (0.5 g) was chromatographedon a column of silica gel (50 g). Elution with light petrol-eum-benzene gave 6-deoxyjacareubin (0.05 g), m.p. 210-213O, RF 0.85 (ethyl acetate-chloroform 1 : 9). Elution(3 HI d, J 6.8 Hz, lO-CH,), 8.83 (3 HI d, J 7.0 Hz, ll-CHS),Oxidation of (-)-Inophyllum B (18).Dehydration of soulattrolide (1 3a).8-H), 4.06 (1 H, S , 3-H), 4.64 ( 1 H, d, J 10 Hz, 7-H), 5.08Methylation of soulattrolide (13a).3-H), 4.66 (1 H, d, J 10 Hz, 7-H), 5.39 (1 H, d, J 2.5 Hz,Taraxerol and p-sitosterol1977 151 1with benzene gave l,ti-dihydroxy-5-methoxyxanthone(0.045 g), m.p. 241-242".Fraction (M) (0.5 g)was chromatographed on a column of silica gel (50 g).Elution with light petroleum-benzene (3 : 1) gave l-hydroxy-5-methoxyxanthone, m.p. 213-214" (from acetone) (lit.,16214-215"), RF 0.50 (ethyl acetate-light petroleum, 3 : 17),identical with an authentic sample (mixed m.p., i.r. spectra,and t.1.c.).6-Deoxyjacereubin ( 10a), 1,6-dihydroxy-5-methoxyxanthone(12a), and p-sitosterol. Further elution of the column withbenzene gave 6-deoxyjacareubin (0.050 g), m.p. 210-213",1,6-dihydroxy-5-methoxyxanthone (0.100 g), m.p. 241-242"; and p-sitosterol (0.020 g), m.p. 136-137".1,3,5-Trihydroxy-2-( 3-methylbut-2-enyl)xanthone (6a).The solid (N) (0.500 g) on repeated crystallisation frommethanol-chloroform ( 1 : 1) gave 1,3,5-trihydroxy-2-( 3-methylbut-2-eny1)xanthone (0.300 g), m.p.280-282".With diazomethane in ether, it gave l-hydroxy-3,5-di-methoxy-2-( 3-methylbut-2-enyl)xanthone, m.p. 166-168".Both compounds were identical with authentic samples(mixed m.p., i.r. spectra, and t.1.c.). The mother liquorfrom crystallisation of (N) formed fraction (P) (0.175 g).Fraction (P) (0.150 g) waschromatographed on a column of silica gel (25 g) . Elutionwith benzene-chloroform (2 : 1) gave 1,7-dihydroxyxan-thone (0.020 g), m.p. 239" (from toluene), RF 0.70 (ethylacetate-chloroform, 1 : 9). Further elution with chloro-form-methanol ( 1 : 1) gave 1,3,5-trihydroxy-2-(3-methyl-but-2-eny1)xanthone (0.010 g), m.p. 280-284".l-Hydroxy-5-methoxyxanthone (12b).1,7-DZhydroxyxanthone (9).6-Deoxyjacareubzn ( IOa) , I, ti-dahydroxy-5-methoxyxanthom( 12a), p-sitosterol, and 1,7-dihydroxyxanthone (9). The gum(0) (0.500 g) was chromatographed on a solumn of silica gel(50 g). Elution with (i) light petroleum-benzene (1 : 1)gave 6-deoxyjacareubin (0.010 g); (ii) benzene gave 1,6-dihydroxy-5-methoxyxanthone (0.020 g) and p-sitosterol(0.010 g); and (iii) benzene-chloroform (2 : 1) gave 1,7-dihydroxyxanthone (0.050 g) .We thank Professors W. D. Ollis (University of Slieffield),R. H. Thomson (University of Aberdeen), and M. Shaniiiia(Pennsylvania State University), Dr. P. Bladon (Uni-versity of Strathclyde), and Mr. M. J. Nagler (TropicalProducts Institute) for n.m.r. and mass spectral data;Dr. S. Balasubramaniam for collection of plant material;Madam J. Polonsky (CNRS, Paris) for the i.r. comparisonof ( - ) -trans-inophyllolide and methyl isoapetalate withauthentic samples; Dr. V. Kumar for discussions; andMrs. S. C. Weerasekera, Ms. S. Ramachandran, and D. V.Ariyapala for technical assistance. One of us (M. U. S. S.)thanks the Australian National University for a visitingFellowship and Professor A. J. Birch for his interest,hospitality, and facilities for completion of the writing up ofthis paper. The programme has been supported in part bygrants by the National Science Council of Sri La6ka and bythe U. S. Department of Agriculture.[6/1860 Received, 4th October, 1976

ISSN:1472-7781    

DOI:10.1039/P19770001505

出版商:RSC    

年代:1977

数据来源: RSC