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Sesquiterpene hydrocarbons in the liverwort dumortiera hirsuta
\
Pergamon PII] S9920Ð8311"86#99373Ð5
Phytochemistry\ Vol[ 37\ No[ 5\ pp[ 0908Ð0912\ 0887 Þ 0887 Elsevier Science Ltd[ All rights reserved Printed in Great Britain 9920Ð8311:87 ,08[99¦9[99
SESQUITERPENE HYDROCARBONS IN THE LIVERWORT DUMORTIERA HIRSUTA YUÝCEL SARITAS\ NILS BUÝLOW\ CHRISTIANE FRICKE\ WILFRIED A[ KOÝNIG and HERMAN MUHLE$ Institut fur Organische Chemie\ Universitat Hamburg\ D!19035 Hamburg\ Germany^ $Abteilung Spezielle Botanik\ Universitat Ulm\ D!78980 Ulm\ Germany "Received in revised form 5 May 0886#
Key Word Index*Dumortiera hirsuta^ Liverwort^ Hepaticae^ sesquiterpene hydrocarbons^ stereochemistry^ 1!dimensional gas chromatography^ cyclodextrin derivatives[
Abstract*From a sample of the liverwort Dumortiera hirsuta "Sw[# Nees collected near Sao Francisco de Paula\ Rio Grande do Sul "Brazil# a series of sesquiterpene hydrocarbons was isolated by preparative gas chromatography "GC# and investigated by spectroscopic methods and 1!dimensional GC "1D!GC# using a combination of a conventional polysiloxane capillary column and a capillary with a cyclodextrin derivative[ Some rare sesquiterpenes such as "−#!cyclosativene\ "¦#!b!copaene\ "−#!aristolochene\ "¦#!aciphyllene and "−#!isoguaiene were identi_ed as well as the unusual enantiomers "¦#!a!copaene\ "¦#!cis!a!bergamotene\ "¦#! trans!a!bergamotene\ "¦#!a!guaiene\ "¦#!guaia!5\8!diene and "¦#!b!caryophyllene[ Þ 0887 Elsevier Science Ltd[ All rights reserved
INTRODUCTION
Liverworts are known to produce a large variety of sesquiterpenoids[ In a Japanese sample of Dumortiera hirsuta a number of known sesquiterpene hydro! carbons was identi_ed by GC!mass spectrometric investigations by Matsuo et al[ ð0Ł[ More recently Asakawa et al[ ð1Ł isolated and identi_ed a new ses! quiterpene and 02 known oxygenated compounds from the ether extract of the same species[ However\ the occurrence of at least three chemical races of D[ hirsuta in Japan ð2Ł indicates a large natural varia! bility[ In a sample of the liverwort collected in Brazil only sesquiterpene hydrocarbons were detected by GC!mass spectrometry of a hydrodistillate[ Most of these constituents were identi_ed by their typical mass spectra\ some others with mass spectra which could not easily be assigned were isolated and investigated by NMR and by enantioselective GC[
RESULTS AND DISCUSSION
As illustrated by Fig[ 0\ the hydrodistillate of D[ hirsuta consists of a complex mixture of closely eluting isomeric sesquiterpene hydrocarbons\ which could not be easily isolated[ In a _rst separation step the bulk of the main constituents "−#!isoguaiene "06# and Z!
Author to whom correspondence should be addressed[
Fig[ 0[ Gas chromatographic separation of the hydro! distillation products of the liverwort Dumortiera hirsuta[ 14 m fused!silica capillary column with polysiloxane CpSil 4[ Column temp[ 49>\ temp[ Programme 2> min−0 to 129>[ Peak assignment see Table 0[
g!bisabolene "07# was removed by preparative GC ð3Ł and further puri_ed by preparative TLC for NMR investigations[ The 0H NMR spectrum of 06 was identical with that published by Bohlmann et al[ ð4Ł[ The negative optical rotation and 1D!GC analysis\ however\ revealed that the unusual "−#!enantiomer was present[
0908
0919
Y[ SARITAS et al[
The occurrence of the unusual enantiomers of ses! quiterpenes in liverworts has been observed by Huneck and Klein ð5Ł for the _rst time and was con! _rmed by recent investigations of hydrodistillation products of several liverworts by enantioselective GC ð6\ 7Ł[ Stereochemical assignments were achieved by comparison with reference compounds of known con! _guration and by 1D!GC[ In the case of g!bisabolene complete 0H NMR data of the E!isomer were also published by Bohlmann et al[ ð8Ł[ Our assignment of 07 as the Z!isomer is based on 1D NMR data and a diagnostic NOE correlation between the C!03 methyl protons and the C!0 methylene protons and their allylic position to an ole_nic double bond[ The remaining fraction of the essential oil of D[
Scheme 0
Table 0[ Enantiomeric composition of the sesquiterpene hydrocarbons of Dumortiera hirsuta as determined by two! dimensional enantioselective gas chromatography
Sesquiterpene
Percentage Percentage "¦#!Enantiomer "−#!Enantiomer
0[ a!Cubebene 14 1[ Cyclosativene * 2[ a!Copaene 099 3[ cis!a!Bergamotene 099 4[ b!Caryophyllene 84 5[ b!Copaene 62 6[ a!Guaiene 73 7[ trans!a!Bergamotene099 8[ Guaia!5\8!diene 099 09[ Unknown * 00[ "E#!b!Farnesene * 01[ Unknown * 02[ a!Curcumene 76 03[ Aristolochene * 04[ Valencene 099 05[ Aciphyllene 099 06[ Isoguaiene * 07[ "Z#!g!Bisabolene * 08[ epi!a!Selinene *
64 099 * * 4 16 05 * * * * * 02 099 * * 099 * 099
hirsuta "Fraction 0\ Fig[ 1# was further investigated by GC!mass spectrometry[ The compounds listed in Scheme 0 and Table 0 were identi_ed by comparison of their electron impact mass spectra and retention indices on several capillary columns with polysiloxane phases "CpSil 4 and CpSil 08# and cyclodextrin deriva! tives with previously isolated reference compounds[ For stereochemical analysis 1D!GC was applied using a capillary column with a conventional stationary phase for preseparation and a second capillary column with heptakis"1\5!di!O!methyl!2!O!pentyl#!b!cyclo! dextrin for the determination of enantiomeric com! positions as demonstrated in Fig[ 1 for cis!a!berga! motene "3# and aristolochene "03#[ Reference com! pounds^ "−#!cis!a!bergamotene\ isolated previously by preparative GC from opoponax oil\ a sample of "−#!aristolochene which was prepared by synthesis from "¦#!valencene according to Cane et al[ ð09Ł and a sample of "¦#!aristolochene\ isolated before from the essential oil of the liverwort Porella arboris!vitae ð00Ł[ As shown in Table 0\ b!caryophyllene "4#\ b! copaene "5#\ a!guaiene "6# and a!curcumene "02# are present as enantiomeric mixtures with the {unusual| enantiomer in large excess[ Although unusual enanti! omers are common in liverworts the Marchantiales usually contain "−#!b!caryophyllene and "−#!b!car! yophylleneoxide ð2Ł[ In the case of cyclosativene "1#\ a!copaene "2#\ cis!a!bergamotene "3#\ trans!a!berga! motene "7#\ guaia!5\8!diene "8# and aristolochene "03# only the unusual enantiomers were detected[ For the bergamotenes this is the _rst natural occurrence of the "¦#!enantiomer[ Aciphyllene "05#\ a rare ses! quiterpene hydrocarbon with the guaiane skeleton\ was _rst reported as a constituent of Lindera `lauca
Sesquiterpene hydrocarbons from Dumortiera hirsuta
0910
Fig[ 1[ 1!Dimensional gas chromatographic investigation of fraction 0 of the hydrodistillate of Dumortiera hirsuta[ Upper part] preseparation on a 14 m capillary column with CpSil 4\ column temp[ 59>\ temp[ Programme 2> min−0 to 199>[ Lower part] transferred fractions of cis!a!bergamotene "left# and aristolochene "right# to a 14 m capillary column with heptakis"1\5! di!O!methyl!2!O!pentyl#!b!cyclodextrin at 099> "left# and 009> "right# and comparison with reference compounds under identical conditions[
0911
Y[ SARITAS et al[
"Sieb[ et Zucc[# by Kubota et al[ ð01Ł[ We have recently isolated aciphyllene as a minor constituent from pat! chouli oil "unpublished observation#[ In all cases the enantiomer with positive optical rotation was found[ Finally\ the "−#!enantiomer of 6!epi!a!selinene "08# was identi_ed[ We have found this compound before in the liverwort Pellia epiphylla\ and in the higher plants Nardostachys jatamanii and Bixa orellana[ The "¦#!enantiomer of this compound was described as a constituent of Dipterocarpus alatus Roxb[ "gurjun balsam oil# ð02Ł and is also present in the liverwort Porella arboris!vitae ð00Ł[ a!Cubebene "0# with the "−#!enantiomer in excess\ "¦#!valencene "04# and E! b!farnesene "00# were the only constituents which are also common in higher plants[ Two minor com! ponents eluting in front and behind 00 could not be identi_ed[
EXPERIMENTAL
Plant material[ Dumortiera hirsuta was collected near Sao Francisco de Paula\ Rio Grande do Sul\ Brazil\ and identi_ed by H[ Muhle ð03Ł[ The collected liverwort is deposited in the Abteilung fur Spezielle Botanik\ Universitat Ulm "voucher no[ 039385!0!04#[ Hydrodistillation[ The essential oil of D[ hirsuta was prepd by hydrodistillation "1 hr# of aq[ homogenates of fresh and green plants using n!hexane as collection solvent[ Because of the greatly di}ering weight\ the fresh material was not weighed[ Enantioselective capillary GC[ Capillary columns with cyclodextrin derivatives were prepd as described in ref[ ð04Ł[ Two!dimensional GC[ The essential oil samples were injected on a 14 m "9[14 mm i[d[# capillary column containing nonpolar CpSil 4 "Chrompack# in a Sie! mens Sichromat 1 gas chromatograph "equipped with a T!piece live!switching unit# at 49> and programmed at a rate of 2> min−0 to 199>[ Sample transfer was performed manually to a 14 m capillary column with heptakis"1\5!di!O!methyl!2!O!pentyl#!b!cyclodextrin "49) in polysiloxane OV 0690# which was isothermal at 84\ 099\ 094 or 009>\ depending on the solute[ The chromatograms from both columns were recorded with a two!channel MerckÐHitachi model 1499 inte! grator[ H1 at an entrance pressure of 79 kPa for the CpSil 4 capillary and 54 kPa for the cyclodextrin capil! lary was used as a carrier gas[ NMR spectroscopy[ NMR measurements were per! formed with WM 399 "399 MHz# instrument "Bruker# using TMS as int[ standard[ GC!MS[ Electron impact "69 eV# GC!MS measure! ments were carried out on a Hewlett Packard HP 4789 gas chromatograph equipped with a 14 m CpSil 4 "Chrompack# fused!silica capillary column coupled to a VG Analytical VG 69!149S mass spectrometer[ Polarimetry[ Optical rotation measurements were performed with a PerkinÐElmer 130 polarimeter[ Isolation of sesquiterpene constituents[ Isoguaiene
"06# and Z!g!bisabolene "07# were collected in one fr[ by prep[ GC on a Varian 0399 instrument\ equipped with a stainless steel column "0[7 m×3[2 mm i[d[# with 4) heptakis"1\5!di!O!methyl!2!O!pentyl#!b!cyclo! dextrin:OV!0690 "0]0# on Chromosorb W!HP[ He was used as carrier gas at a ~ow rate of 139 ml min−0[ Compounds 06 and 07 were sepd and puri_ed by prep[ TLC on silica gel 59 F143 "MachereyÐNagel# using n! hexane as the mobile phase[ Known compounds were identi_ed by comparison of their Rt and MS with those of authentic materials[ The Rt were measured on a two channel gas chromatograph "Orion# equipped with 14 m CpSil 4 and CpSil 08 "Chrom! pack# capillary columns[ b!Copaene "5#[ MS "EI\ 69 eV#\ m:z "rel[ int[#] 193 "8#\ 050 "099#\ 022 "05#\ 019 "08#\ 008 "14#\ 096 "09#\ 094 "39#\ 82 "12#\ 80 "23#\ 70 "10#\ 68 "19#\ 66 "04#\ 58 "00#\ 56 "00#\ 44 "05#\ 30 "17#[ Aristolochene "03#[ MS "EI\ 69 eV#\ m:z "rel[ int[#] 193 "03#\ 078 "53#\ 051 "09#\ 050 "20#\ 036 "10#\ 025 "07#\ 022 "27#\ 010 "37#\ 008 "33#\ 096 "44#\ 094 "099#\ 82 "50#\ 70 "22#\ 68 "30#\ 66 "17#\ 58 "10#\ 56 "13#\ 44 "27#\ 32 "02#\ 30 "52#[ Aciphyllene "05#[ 0H NMR "CDCl2#] d 3[55 "0H\ s#\ 3[48 "0H\ s#\ 1[84 "0H\ m#\ 1[39 "0H\ br d\ J 02[2 Hz#\ 1[02Ð1[29 "1H\ m#\ 1[99Ð1[02 "2H\ m#\ 0[84 "0H\ ddt\ Jd0 02[9 Hz\ Jd1 4[9 Hz\ Jt 7[7 Hz#\ 0[79Ð 0[89 "0H\ m#\ 0[61 "2H\ s#\ 0[49Ð0[62 "2H\ m#\ 0[46 "2H\ s#\ 0[34 "0H\ dddd\ J0 02 Hz\ J1 8[4 Hz\ J2 5[4 Hz\ J3 5[2 Hz#\ 9[64 "2H\ d\ J 6[9 Hz#[ 02 C NMR "CDCl2#] d 01[83 "q#\ 03[03 "q#\ 19[12 "q#\ 17[41 "t#\ 20[85 "t#\ 24[03 "t#\ 25[85 "d#\ 26[09 "t#\ 26[33 "t#\ 34[61 "d#\ 42[17 "d#\ 096[44 "t#\ 021[43 "s#\ 024[06 "s#\ 041[72 "s#[ MS "EI\ 69 eV#\ m:z "rel[ int[#] 193 "28#\ 078 "41#\ 064 "02#\ 050 "17#\ 036 "38#\ 022 "24#\ 010 "11#\ 008 "22#\ 097 "12#\ 096 "27#\ 094 "46#\ 84 "099#\ 82 "44#\ 80 "49#\ 70 "21#\ 68 "55#\ 66 "24#\ 58 "05#\ 56 "24#\ 54 "02#\ 44 "30#\ 42 "12#\ 32 "03#\ 30 "51#[ Iso`uaiene "06#[ MS "EI\ 69 eV#\ m:z "rel[ int[#] 193 "81#\ 078 "70#\ 050 "099#\ 036 "22#\ 022 "39#\ 020 "03#\ 010 "08#\ 008 "60#\ 006 "04#\ 098 "03#\ 096 "20#\ 094 "65#\ 84 "10#\ 82 "25#\ 80 "50#\ 70 "20#\ 68 "15#\ 66 "16#\ 58 "10#\ 56 "08#\ 54 "01#\ 44 "25#\ 42 "05#\ 32 "08#\ 30 "46#[ Z!g!Bisabolene "07#[ 0H NMR "C5D5#] d 4[39 "0H\ br s#\ 4[11 "0H\ br s#\ 1[71 "1H\ br s#\ 1[20 "1H\ t\ J 5[2 Hz#\ 1[02 "3H\ m#\ 0[83 "1H\ t\ J 5[2 Hz#\ 0[69 "2H\ s#\ 0[55 "2H\ s#\ 0[52 "2H\ s#\ 0[43 "2H\ s#[ 02 C NMR "C5D5#] d 022[86 "s#\ 020[10 "s#\ 014[56 "s#\ 014[29 "d#\ 010[26 "d#\ 23[72 "t#\ 20[72 "t#\ 18[70\ 16[22 "t#\ 16[13 "t#\ 14[75\ 12[46\ 07[99\ 06[55[ MS "EI\ 69 eV#\ m:z "rel[ int[#] 193 "16#\ 078 "3#\ 050 "00#\ 036 "7#\ 024 "12#\ 023 "15#\ 022 "03#\ 010 "13#\ 008 "51#\ 096 "57#\ 094 "18#\ 82 "099#\ 80 "39#\ 68 "26#\ 66 "15#\ 58 "16#\ 56 "01#\ 44 "28#\ 42 "04#\ 32 "24#\ 30 "67#[ 6!epi!a!Selinene "08#[ MS "EI\ 69 eV#\ m:z "rel[ int[#] 193 "04#\ 078 "09#\ 050 "88#\ 036 "5#\ 022 "03#\ 011 "099#\ 008 "07#\ 096 "47#\ 094 "17#\ 84 "02#\ 82 "21#\ 80 "29#\ 70 "21#\ 68 "13#\ 66 "07#\ 58 "038#\ 56 "19#\ 44 "29#\ 42 "19#\ 32 "09#\ 30 "40#[
Sesquiterpene hydrocarbons from Dumortiera hirsuta
Acknowled`ements*We thank Dr V[ Sinnwell\ Uni! versity of Hamburg\ for his help in the interpretation of NMR spectra and the Fonds der Chemischen Indu! strie for _nancial support[
REFERENCES
0[ Matsuo\ A[\ Uto\ S[\ Nakayama\ M[ and Hayashi\ S[\ Zeitschrift fur Naturforschun`\ 0865\ 20c\ 390[ 1[ Toyota\ M[\ Yoshida\ T[\ Matsunami\ J[ and Asakawa\ Y[\ Phytochemistry\ 0885\ 33\ 182[ 2[ Asakawa\ Y[\ in Pro`ress in the Chemistry of Or`anic Natural Products\ Vol[ 54\ ed[ W[ Herz\ G[ W[ Kirby\ R[ E[ Moore\ W[ Steglich and Ch[ Tamm[ Springer\ Vienna\ 0884\ p[ 0[ 3[ Hardt\ I[ H[ and Konig\ W[ A[\ Journal of Chro! mato`raphy\ A\ 0883\ 555\ 500[ 4[ Bohlmann\ F[\ Zdero\ C[ and Lonitz\ M[\ Phyto! chemistry\ 0866 05\ 464[
0912
5[ Huneck\ S[ and Klein\ E[\ Phytochemistry\ 0856\ 5\ 272[ 6[ Fricke\ C[\ Rieck\ A[\ Hardt\ I[ H[\ Konig\ W[ A[ and Muhle H[\ Phytochemistry\ 0884\ 28\ 0008[ 7[ Konig\ W[ A[\ Bulow\ N[\ Fricke\ C[\ Melching\ S[\ Rieck\ A[ and Muhle\ H[\ Phytochemistry\ 0885\ 32\ 518[ 8[ Bohlmann\ F[\ Knoll\ K[!H[\ King\ R[ M[ and Robinson\ H[\ Phytochemistry\ 0868\ 07\ 0886[ 09[ Cane\ D[ E[\ Salaski\ E[ J[ and Prabhakaran\ P[ C[\ Tetrahedron Letters\ 0889\ 20\ 0832[ 00[ Fricke\ C[ and Konig\ W[ A[ "unpublished#[ 01[ Nii\ H[\ Furukawa\ K[\ Iwakirir\ M[ and Kubota\ T[\ Nippon No`eika`aku Kaishi\ 0872\ 46\ 622[ 02[ Klein\ E[ and Rojahn\ W[\ Tetrahedron Letters\ 0869\ 168[ 03[ Vianna\ C[\ Boletin do Instituto de Biosciencias\ 0874\ 27\ 82[ 04[ Konig\ W[ A[\ Kruger\ A[\ Icheln\ D[ and Runge\ T[\ Journal of Hi`h Resolution Chromato`raphy\ 0881\ 04\ 073[
Pergamon PII] S9920Ð8311"86#99373Ð5
Phytochemistry\ Vol[ 37\ No[ 5\ pp[ 0908Ð0912\ 0887 Þ 0887 Elsevier Science Ltd[ All rights reserved Printed in Great Britain 9920Ð8311:87 ,08[99¦9[99
SESQUITERPENE HYDROCARBONS IN THE LIVERWORT DUMORTIERA HIRSUTA YUÝCEL SARITAS\ NILS BUÝLOW\ CHRISTIANE FRICKE\ WILFRIED A[ KOÝNIG and HERMAN MUHLE$ Institut fur Organische Chemie\ Universitat Hamburg\ D!19035 Hamburg\ Germany^ $Abteilung Spezielle Botanik\ Universitat Ulm\ D!78980 Ulm\ Germany "Received in revised form 5 May 0886#
Key Word Index*Dumortiera hirsuta^ Liverwort^ Hepaticae^ sesquiterpene hydrocarbons^ stereochemistry^ 1!dimensional gas chromatography^ cyclodextrin derivatives[
Abstract*From a sample of the liverwort Dumortiera hirsuta "Sw[# Nees collected near Sao Francisco de Paula\ Rio Grande do Sul "Brazil# a series of sesquiterpene hydrocarbons was isolated by preparative gas chromatography "GC# and investigated by spectroscopic methods and 1!dimensional GC "1D!GC# using a combination of a conventional polysiloxane capillary column and a capillary with a cyclodextrin derivative[ Some rare sesquiterpenes such as "−#!cyclosativene\ "¦#!b!copaene\ "−#!aristolochene\ "¦#!aciphyllene and "−#!isoguaiene were identi_ed as well as the unusual enantiomers "¦#!a!copaene\ "¦#!cis!a!bergamotene\ "¦#! trans!a!bergamotene\ "¦#!a!guaiene\ "¦#!guaia!5\8!diene and "¦#!b!caryophyllene[ Þ 0887 Elsevier Science Ltd[ All rights reserved
INTRODUCTION
Liverworts are known to produce a large variety of sesquiterpenoids[ In a Japanese sample of Dumortiera hirsuta a number of known sesquiterpene hydro! carbons was identi_ed by GC!mass spectrometric investigations by Matsuo et al[ ð0Ł[ More recently Asakawa et al[ ð1Ł isolated and identi_ed a new ses! quiterpene and 02 known oxygenated compounds from the ether extract of the same species[ However\ the occurrence of at least three chemical races of D[ hirsuta in Japan ð2Ł indicates a large natural varia! bility[ In a sample of the liverwort collected in Brazil only sesquiterpene hydrocarbons were detected by GC!mass spectrometry of a hydrodistillate[ Most of these constituents were identi_ed by their typical mass spectra\ some others with mass spectra which could not easily be assigned were isolated and investigated by NMR and by enantioselective GC[
RESULTS AND DISCUSSION
As illustrated by Fig[ 0\ the hydrodistillate of D[ hirsuta consists of a complex mixture of closely eluting isomeric sesquiterpene hydrocarbons\ which could not be easily isolated[ In a _rst separation step the bulk of the main constituents "−#!isoguaiene "06# and Z!
Author to whom correspondence should be addressed[
Fig[ 0[ Gas chromatographic separation of the hydro! distillation products of the liverwort Dumortiera hirsuta[ 14 m fused!silica capillary column with polysiloxane CpSil 4[ Column temp[ 49>\ temp[ Programme 2> min−0 to 129>[ Peak assignment see Table 0[
g!bisabolene "07# was removed by preparative GC ð3Ł and further puri_ed by preparative TLC for NMR investigations[ The 0H NMR spectrum of 06 was identical with that published by Bohlmann et al[ ð4Ł[ The negative optical rotation and 1D!GC analysis\ however\ revealed that the unusual "−#!enantiomer was present[
0908
0919
Y[ SARITAS et al[
The occurrence of the unusual enantiomers of ses! quiterpenes in liverworts has been observed by Huneck and Klein ð5Ł for the _rst time and was con! _rmed by recent investigations of hydrodistillation products of several liverworts by enantioselective GC ð6\ 7Ł[ Stereochemical assignments were achieved by comparison with reference compounds of known con! _guration and by 1D!GC[ In the case of g!bisabolene complete 0H NMR data of the E!isomer were also published by Bohlmann et al[ ð8Ł[ Our assignment of 07 as the Z!isomer is based on 1D NMR data and a diagnostic NOE correlation between the C!03 methyl protons and the C!0 methylene protons and their allylic position to an ole_nic double bond[ The remaining fraction of the essential oil of D[
Scheme 0
Table 0[ Enantiomeric composition of the sesquiterpene hydrocarbons of Dumortiera hirsuta as determined by two! dimensional enantioselective gas chromatography
Sesquiterpene
Percentage Percentage "¦#!Enantiomer "−#!Enantiomer
0[ a!Cubebene 14 1[ Cyclosativene * 2[ a!Copaene 099 3[ cis!a!Bergamotene 099 4[ b!Caryophyllene 84 5[ b!Copaene 62 6[ a!Guaiene 73 7[ trans!a!Bergamotene099 8[ Guaia!5\8!diene 099 09[ Unknown * 00[ "E#!b!Farnesene * 01[ Unknown * 02[ a!Curcumene 76 03[ Aristolochene * 04[ Valencene 099 05[ Aciphyllene 099 06[ Isoguaiene * 07[ "Z#!g!Bisabolene * 08[ epi!a!Selinene *
64 099 * * 4 16 05 * * * * * 02 099 * * 099 * 099
hirsuta "Fraction 0\ Fig[ 1# was further investigated by GC!mass spectrometry[ The compounds listed in Scheme 0 and Table 0 were identi_ed by comparison of their electron impact mass spectra and retention indices on several capillary columns with polysiloxane phases "CpSil 4 and CpSil 08# and cyclodextrin deriva! tives with previously isolated reference compounds[ For stereochemical analysis 1D!GC was applied using a capillary column with a conventional stationary phase for preseparation and a second capillary column with heptakis"1\5!di!O!methyl!2!O!pentyl#!b!cyclo! dextrin for the determination of enantiomeric com! positions as demonstrated in Fig[ 1 for cis!a!berga! motene "3# and aristolochene "03#[ Reference com! pounds^ "−#!cis!a!bergamotene\ isolated previously by preparative GC from opoponax oil\ a sample of "−#!aristolochene which was prepared by synthesis from "¦#!valencene according to Cane et al[ ð09Ł and a sample of "¦#!aristolochene\ isolated before from the essential oil of the liverwort Porella arboris!vitae ð00Ł[ As shown in Table 0\ b!caryophyllene "4#\ b! copaene "5#\ a!guaiene "6# and a!curcumene "02# are present as enantiomeric mixtures with the {unusual| enantiomer in large excess[ Although unusual enanti! omers are common in liverworts the Marchantiales usually contain "−#!b!caryophyllene and "−#!b!car! yophylleneoxide ð2Ł[ In the case of cyclosativene "1#\ a!copaene "2#\ cis!a!bergamotene "3#\ trans!a!berga! motene "7#\ guaia!5\8!diene "8# and aristolochene "03# only the unusual enantiomers were detected[ For the bergamotenes this is the _rst natural occurrence of the "¦#!enantiomer[ Aciphyllene "05#\ a rare ses! quiterpene hydrocarbon with the guaiane skeleton\ was _rst reported as a constituent of Lindera `lauca
Sesquiterpene hydrocarbons from Dumortiera hirsuta
0910
Fig[ 1[ 1!Dimensional gas chromatographic investigation of fraction 0 of the hydrodistillate of Dumortiera hirsuta[ Upper part] preseparation on a 14 m capillary column with CpSil 4\ column temp[ 59>\ temp[ Programme 2> min−0 to 199>[ Lower part] transferred fractions of cis!a!bergamotene "left# and aristolochene "right# to a 14 m capillary column with heptakis"1\5! di!O!methyl!2!O!pentyl#!b!cyclodextrin at 099> "left# and 009> "right# and comparison with reference compounds under identical conditions[
0911
Y[ SARITAS et al[
"Sieb[ et Zucc[# by Kubota et al[ ð01Ł[ We have recently isolated aciphyllene as a minor constituent from pat! chouli oil "unpublished observation#[ In all cases the enantiomer with positive optical rotation was found[ Finally\ the "−#!enantiomer of 6!epi!a!selinene "08# was identi_ed[ We have found this compound before in the liverwort Pellia epiphylla\ and in the higher plants Nardostachys jatamanii and Bixa orellana[ The "¦#!enantiomer of this compound was described as a constituent of Dipterocarpus alatus Roxb[ "gurjun balsam oil# ð02Ł and is also present in the liverwort Porella arboris!vitae ð00Ł[ a!Cubebene "0# with the "−#!enantiomer in excess\ "¦#!valencene "04# and E! b!farnesene "00# were the only constituents which are also common in higher plants[ Two minor com! ponents eluting in front and behind 00 could not be identi_ed[
EXPERIMENTAL
Plant material[ Dumortiera hirsuta was collected near Sao Francisco de Paula\ Rio Grande do Sul\ Brazil\ and identi_ed by H[ Muhle ð03Ł[ The collected liverwort is deposited in the Abteilung fur Spezielle Botanik\ Universitat Ulm "voucher no[ 039385!0!04#[ Hydrodistillation[ The essential oil of D[ hirsuta was prepd by hydrodistillation "1 hr# of aq[ homogenates of fresh and green plants using n!hexane as collection solvent[ Because of the greatly di}ering weight\ the fresh material was not weighed[ Enantioselective capillary GC[ Capillary columns with cyclodextrin derivatives were prepd as described in ref[ ð04Ł[ Two!dimensional GC[ The essential oil samples were injected on a 14 m "9[14 mm i[d[# capillary column containing nonpolar CpSil 4 "Chrompack# in a Sie! mens Sichromat 1 gas chromatograph "equipped with a T!piece live!switching unit# at 49> and programmed at a rate of 2> min−0 to 199>[ Sample transfer was performed manually to a 14 m capillary column with heptakis"1\5!di!O!methyl!2!O!pentyl#!b!cyclodextrin "49) in polysiloxane OV 0690# which was isothermal at 84\ 099\ 094 or 009>\ depending on the solute[ The chromatograms from both columns were recorded with a two!channel MerckÐHitachi model 1499 inte! grator[ H1 at an entrance pressure of 79 kPa for the CpSil 4 capillary and 54 kPa for the cyclodextrin capil! lary was used as a carrier gas[ NMR spectroscopy[ NMR measurements were per! formed with WM 399 "399 MHz# instrument "Bruker# using TMS as int[ standard[ GC!MS[ Electron impact "69 eV# GC!MS measure! ments were carried out on a Hewlett Packard HP 4789 gas chromatograph equipped with a 14 m CpSil 4 "Chrompack# fused!silica capillary column coupled to a VG Analytical VG 69!149S mass spectrometer[ Polarimetry[ Optical rotation measurements were performed with a PerkinÐElmer 130 polarimeter[ Isolation of sesquiterpene constituents[ Isoguaiene
"06# and Z!g!bisabolene "07# were collected in one fr[ by prep[ GC on a Varian 0399 instrument\ equipped with a stainless steel column "0[7 m×3[2 mm i[d[# with 4) heptakis"1\5!di!O!methyl!2!O!pentyl#!b!cyclo! dextrin:OV!0690 "0]0# on Chromosorb W!HP[ He was used as carrier gas at a ~ow rate of 139 ml min−0[ Compounds 06 and 07 were sepd and puri_ed by prep[ TLC on silica gel 59 F143 "MachereyÐNagel# using n! hexane as the mobile phase[ Known compounds were identi_ed by comparison of their Rt and MS with those of authentic materials[ The Rt were measured on a two channel gas chromatograph "Orion# equipped with 14 m CpSil 4 and CpSil 08 "Chrom! pack# capillary columns[ b!Copaene "5#[ MS "EI\ 69 eV#\ m:z "rel[ int[#] 193 "8#\ 050 "099#\ 022 "05#\ 019 "08#\ 008 "14#\ 096 "09#\ 094 "39#\ 82 "12#\ 80 "23#\ 70 "10#\ 68 "19#\ 66 "04#\ 58 "00#\ 56 "00#\ 44 "05#\ 30 "17#[ Aristolochene "03#[ MS "EI\ 69 eV#\ m:z "rel[ int[#] 193 "03#\ 078 "53#\ 051 "09#\ 050 "20#\ 036 "10#\ 025 "07#\ 022 "27#\ 010 "37#\ 008 "33#\ 096 "44#\ 094 "099#\ 82 "50#\ 70 "22#\ 68 "30#\ 66 "17#\ 58 "10#\ 56 "13#\ 44 "27#\ 32 "02#\ 30 "52#[ Aciphyllene "05#[ 0H NMR "CDCl2#] d 3[55 "0H\ s#\ 3[48 "0H\ s#\ 1[84 "0H\ m#\ 1[39 "0H\ br d\ J 02[2 Hz#\ 1[02Ð1[29 "1H\ m#\ 1[99Ð1[02 "2H\ m#\ 0[84 "0H\ ddt\ Jd0 02[9 Hz\ Jd1 4[9 Hz\ Jt 7[7 Hz#\ 0[79Ð 0[89 "0H\ m#\ 0[61 "2H\ s#\ 0[49Ð0[62 "2H\ m#\ 0[46 "2H\ s#\ 0[34 "0H\ dddd\ J0 02 Hz\ J1 8[4 Hz\ J2 5[4 Hz\ J3 5[2 Hz#\ 9[64 "2H\ d\ J 6[9 Hz#[ 02 C NMR "CDCl2#] d 01[83 "q#\ 03[03 "q#\ 19[12 "q#\ 17[41 "t#\ 20[85 "t#\ 24[03 "t#\ 25[85 "d#\ 26[09 "t#\ 26[33 "t#\ 34[61 "d#\ 42[17 "d#\ 096[44 "t#\ 021[43 "s#\ 024[06 "s#\ 041[72 "s#[ MS "EI\ 69 eV#\ m:z "rel[ int[#] 193 "28#\ 078 "41#\ 064 "02#\ 050 "17#\ 036 "38#\ 022 "24#\ 010 "11#\ 008 "22#\ 097 "12#\ 096 "27#\ 094 "46#\ 84 "099#\ 82 "44#\ 80 "49#\ 70 "21#\ 68 "55#\ 66 "24#\ 58 "05#\ 56 "24#\ 54 "02#\ 44 "30#\ 42 "12#\ 32 "03#\ 30 "51#[ Iso`uaiene "06#[ MS "EI\ 69 eV#\ m:z "rel[ int[#] 193 "81#\ 078 "70#\ 050 "099#\ 036 "22#\ 022 "39#\ 020 "03#\ 010 "08#\ 008 "60#\ 006 "04#\ 098 "03#\ 096 "20#\ 094 "65#\ 84 "10#\ 82 "25#\ 80 "50#\ 70 "20#\ 68 "15#\ 66 "16#\ 58 "10#\ 56 "08#\ 54 "01#\ 44 "25#\ 42 "05#\ 32 "08#\ 30 "46#[ Z!g!Bisabolene "07#[ 0H NMR "C5D5#] d 4[39 "0H\ br s#\ 4[11 "0H\ br s#\ 1[71 "1H\ br s#\ 1[20 "1H\ t\ J 5[2 Hz#\ 1[02 "3H\ m#\ 0[83 "1H\ t\ J 5[2 Hz#\ 0[69 "2H\ s#\ 0[55 "2H\ s#\ 0[52 "2H\ s#\ 0[43 "2H\ s#[ 02 C NMR "C5D5#] d 022[86 "s#\ 020[10 "s#\ 014[56 "s#\ 014[29 "d#\ 010[26 "d#\ 23[72 "t#\ 20[72 "t#\ 18[70\ 16[22 "t#\ 16[13 "t#\ 14[75\ 12[46\ 07[99\ 06[55[ MS "EI\ 69 eV#\ m:z "rel[ int[#] 193 "16#\ 078 "3#\ 050 "00#\ 036 "7#\ 024 "12#\ 023 "15#\ 022 "03#\ 010 "13#\ 008 "51#\ 096 "57#\ 094 "18#\ 82 "099#\ 80 "39#\ 68 "26#\ 66 "15#\ 58 "16#\ 56 "01#\ 44 "28#\ 42 "04#\ 32 "24#\ 30 "67#[ 6!epi!a!Selinene "08#[ MS "EI\ 69 eV#\ m:z "rel[ int[#] 193 "04#\ 078 "09#\ 050 "88#\ 036 "5#\ 022 "03#\ 011 "099#\ 008 "07#\ 096 "47#\ 094 "17#\ 84 "02#\ 82 "21#\ 80 "29#\ 70 "21#\ 68 "13#\ 66 "07#\ 58 "038#\ 56 "19#\ 44 "29#\ 42 "19#\ 32 "09#\ 30 "40#[
Sesquiterpene hydrocarbons from Dumortiera hirsuta
Acknowled`ements*We thank Dr V[ Sinnwell\ Uni! versity of Hamburg\ for his help in the interpretation of NMR spectra and the Fonds der Chemischen Indu! strie for _nancial support[
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