Phytochemistry\ Vol[ 38\ No[ 0\ pp[ 104Ð107\ 0887Þ 0887 Elsevier Science Ltd[ All rights reserved\ Pergamon Printed in Great Britain

9920Ð8311:87:,Ðsee front matterPII] S9920Ð8311"86#99659Ð6

COUMARINS FROM PARAMIGNYA MONOPHYLLA ROOT BARK

VIJAYA KUMAR\� N[ M[ MOHAMED NIYAZ\ SHANTHINI SAMINATHAN and D[ B[ MAHINDA WICKRAMARATNE

Department of Chemistry\ University of Peradeniya\ Peradeniya\ Sri Lanka

"Received 04 September 0886#

Key Word Index*Parami`nya monophylla^ Rutaceae^ root bark^ coumarins^ pyranocoumarins[

Abstract*The root bark of Parami`nya monophylla was found to contain two new coumarins\ 4!methoxy!7\7!dimethyl!09!"6!hydroxy!2\6!dimethylocta!0\4!dien!2!yl#pyranocoumarin and 4!hydroxy!7\7!dimethyl!09!"6!hydroxy!2\6!dimethyl octa!0\4!dien!2!yl#pyranocoumarin[ Þ 0887 Elsevier Science Ltd[ All rights reserved

INTRODUCTION

Parami`nya monophylla is a woody climber growingin moderate altitudes in the dry and wet zones of SriLanka ð0Ł[ We have previously reported the presenceof tirucalladienes in its fruits ð1Ł and sitosterol\ pon!citrin "dentatin#\ nordentatin\ 4!hydroxy! and 4!methoxy!7\7!dimethyl!09!"2\6!dimethylocta!0\5!dien!2!yl#pyranocoumarin in its stem bark ð2Ł[ The rootbark contains\ in addition to the stem bark constitu!ents\ xanthyletin "0# and two new coumarins\ 4!methoxy!7\7!dimethyl!09!"6!hydroxy!2\6!dimethyl!octa!0\4!dien!2!yl#!1H\7H!benzoð0\1!b]4\3!bŁdipyrane!1!one ð4!methoxy!7\7!dimethyl!09!"6!hydroxy!2\6!dimethylocta!0\4!dien!2!yl# pyranocoumarinŁ "1#and 4!hydroxy!7\7!dimethyl!09!"6!hydroxy!2\6!dime!thyl ! octa ! 0\4 ! dien ! 2 ! yl# ! 1H\7H ! benzoð0\1 ! b]4\3!bŁ dipyran!1!one ð4!hydroxy!7\7!dimethyl!09!"6!hydroxy!2\6!dimethyl!octa!0\4!dien!2!yl# pyrano!coumarinŁ "2#[

RESULTS AND DISCUSSION

The dichloromethane extract of the root bark con!tained poncitrin "dentatin#\ nordentatin\ 4!hydroxy!and 4!methoxy!7\7!dimethyl!09!"2\6!dimethylocta!0\5!dien!2!yl#pyranocoumarin\ sitosterol\ xanthyletin"0# and the new coumarins "1 and 2#[

UV spectra suggested that 1 and 2 were linearpyranocoumarins\ while IR indicated that hydroxylgroups were present[ Their 0H NMR spectra showedthem to be 4\7!disubstituted with the coumarin 2!and 3!protons and the pyran ring 5! and 6!protonsappearing as two AB double doublets[ A six!proton

�Author to whom correspondence should be addressed[

104

dimethyl singlet con_rmed that they were dime!thylpyranocoumarins[ A methyl singlet at d 2[70 andthe low!_eld position of the H!3 doublet in the spec!trum of 1 suggested that the 4!position was oxy!genated with an OMe group[ The hydroxyl groupmust therefore be on the side!chain at the 7!position\which from molecular formula considerations wouldhave the formula\ C09H04O[

The 0H NMR spectrum also indicated the presenceof a 0!methylallyl system[ The remaining side!chainsignals in the spectrum run in CDCl2 were two 0Hdouble doublets\ at d 1[48 and 1[80 for CH1 protons\a 1H vinyl proton multiplet at d 4[40 and a 5H methylsinglet at d 0[00[ The multiplet at d 4[40 was resolvedinto two doublets\ trans!coupled to each other"J � 04[4 Hz# when the spectrum was run in C5D5\suggesting that the side!chain contained an E!CH1CH1CHC"OH#Me1 moiety\ probably attachedto the 0!methylallyl system[

Acetylation of 1 with acetic anhydride and pyridinegave an acetate "3#\ but only at higher temperatures\as expected for a tertiary hydroxyl group[ The 0HNMR methyl signal of the Me1C"OH# group wasshifted by 9[02 ppm on acetylation\ providing furtherevidence for the proximity of the methyl groups to thehydroxyl group[ Dehydration of 1 with p!tolu!enesulphonyl chloride gave triene 4\ while alkaline!induced cyclisation gave the cis!acid\ 5[ The coumarinmust therefore have the structure 4!methoxy!7\7!dimethyl!09!"6!hydroxy!2\6!dimethylocta!0\4!dien!2!yl#!1H\7H!benzoð0\1!b]4\3!bŁdipyrane!1!one[

The 0H NMR spectrum of 2 was similar to that of1\ except that the methyl singlet at d 2[70 was absent[When 2 was methylated with CH1N1\ 1 was obtained\indicating that 2 contained a 4!hydroxy group[ Cou!marin 2 must therefore be 4!hydroxy!7\7!dimethyl!09!"6 ! hydroxy ! 2\6 ! dimethylocta ! 0\4!dien!2!yl#pyranocoumarin "2#[

V[ KUMAR et al[105

EXPERIMENTAL

UV] EtOH[ IR] KBr[ 0H NMR] Varian 59 MHz^Brucker 199 and 399 MHz\ CDCl2\ TMS3 int[ stan!dard[ Optical rotations] CHCl2\ 11>[ Prep[ TLC]Merck Silica Gel PF143¦255[ Medium Pressure Liquid"MPLC# and Flash Chromatography "FC#] Merck8274 Kieselgel 59 "129Ð399 mesh ASTM#[ Identitiesof compounds were established by mmp\ IR and 0HNMR comparisons\ unless stated otherwise[

Parami`nya monophylla Wight was collected fromHewaheta in the Kandy district in central Sri Lankaand identi_ed by the late Prof[ S[ Balasubramaniam ofthe Department of Botany of the University[ Voucherspecimen No[ 4:357B is deposited in the UniversityHerbarium[

Extraction

Dried ground root bark "0[7 kg# was extracted suc!cessively in the cold with CH1Cl1 for two 13 h periods[Concn[ of the CH1Cl1 solns gave 29 g of extract[

Chromato`raphy of CH1Cl1 extract

The extract "14 g# on silica gel "014 g# was subjectedto MPLC on silica gel "109 g#[ Elution with hexaneÐ

EtOAc "3]0#\ followed by FC with CH1Cl1Ðhexane"6]2#\ gave 4!methoxy!7\7!dimethyl!09!"2\6!dime!thylocta!0\5!dien!2yl#pyranocoumarin as an oil "0[1g#\ ðaŁD ¦01[9> and poncitrin "1[0 g# as pale yellowneedles from CH1Cl1Ðhexane\ mp 81> "lit[ ð2Ł mp 81>#\while elution with EtOAcÐhexane "3]10#\ after similarFC\ gave sitosterol "29 mg# mp 027> "lit[ ð3Ł mp 026>#\identical with authentic materials[ Elution with hex!aneÐEtOAc "1]2# gave a pale yellow gum which onFC ðEtOAcÐhexane "6]02#Ł yielded prisms of xan!thyletin "0# "29 mg#\ mp 043> "lit[ ð3Ł mp[ 042>Ð043>#and a fr[\ which on FC with CH1Cl1ÐMeOH "86]2#and prep[ TLC ðCH1Cl1ÐMeOH "86]2#Ł\ gave 4!hyd!roxy!7\7!dimethyl!09! "2\6!dimethylocta !0\5!dien!2yl#pyranocoumarin\ as a yellow oil "199 mg#\ ðaŁD¦18>\ and nordentatin "39 mg#\ mp 072> "lit[ ð2Ł mp072>#\ identical with authentic materials[

Elution with EtOAcÐhexane "3]0# gave an oil "1[9g# which on FC ðsilica gel "39 g#Ł using CH1Cl1ÐMeOH"33]0#\ gave 4!methoxy!7\7!dimethyl!09!"6!hydroxy!2\6!dimethylocta!0\4!dien! 2!yl#!1H\7H!benzoð0\1!b]4\3!bŁdipyrane!1!one "1# as a yellow oil "0[0 g#\ ðaŁD−2[8> "c 9[0#[ "Found] C\ 62[0\ H\ 6[2^ C14H29O4

requires C\ 62[0\ H\ 6[3#^ UV lmax nm "log o#] 196"3[01#\ 117 "3[13#\ 169 "3[20# 216 "0[11#[ IR nmax cm−0]2399\ 1899\ 0619\ 0599\ 0499[ 0H NMR "399 MHz#] d

0[00 "5H\ s\ 6?!Me and 7?!H#\ 0[32 and 0[35 "each 2H\

Coumarins from Parami`nya monophylla root bark 106

s\ 7!Me#\ 0[58 "2H\ s\ 2?!Me#\ 1[48 "0H\ dd\ J � 02[3and 5 Hz\ 3?!H#\ 1[80 "0H\ dd\ J � 02[3 and 4[1 Hz\3?!H#\ 2[70 "2H\ s\ 4!OMe#\ 3[89 "0H\ dd\ J � 09[6 and0[9 Hz\ 0?!H#\ 3[84 "0H\ dd\ J � 06[4 and 0[9 Hz\ 0?!H#\ 4[40 "1H\ m\ 4?! and 5?!H#\ 4[57 "0H\ d\ J � 8[8Hz\ 6!H#\ 5[06 "0H\ d\ J � 8[5 Hz\ 2!H#\ 5[25 "0H\ dd\J � 06[3 and 09[6 Hz\ 1?!H#\ 5[44 "0H\ d\ J � 8[8 Hz\5!H# and 6[75 "0H\ d\ J � 8[5 Hz\ 3!H#^ 0H NMR "399MHz\ C5D5#] 0[00 and 0[02 "each 2H\ s\ 6?!Me and 7?!H#\ 0[14 "5H\ s\ 7!Me#\ 0[89 "2H\ s\ 2?!Me#\ 1[68 "0H\ddd\ J � 02[4\ 6[0 and 0[9 Hz\ 3?!H#\ 2[06 "0H\ ddd\J � 02[4\ 6[1 and 0[0 Hz\ 3?!H#\ 2[17 "2H\ s\ 4!OMe#\4[92 "0H\ dd\ J � 09[6 and 0[9 Hz\ 0?!H#\ 4[98 "0H\dd\ J � 06[4 and 0[0 Hz\ 0?!H#\ 4[18 "0H\ d\ J � 8[8Hz\ 6!H#\ 4[51 "0H\ dt\ J � 04[4 and 0[9 Hz\ 5?!H#\4[63 "0H\ dt\ J � 04[4 and 6[1 Hz\ 4?!H#\ 4[81 "0H\ d\J � 8[5 Hz\ 2!H#\ 5[37 "0H\ d\ J � 8[8 Hz\ 5!H#\ 5[46"0H\ dd\ J � 06[4 and 09[6 Hz\ 1?!H#\ 6[21 "0H\ d\J � 8[5 Hz\ 3!H#[ 02C NMR "C5D5#] d 16[3 and 16[4"6?!Me and 7?!C#\ 17[3 "2?!Me#\ 18[8 and 29[9 "7!Me#\32[0 "3?!C#\ 34[2 "2?!C#\ 51[7 "4!OMe#\ 69[0 "6?!C#\ 66[2"7!C#\ 096[6 "3a!C#\ 097[5 "0?!C#\ 000[5 "4a!C#\ 001[1"2!C#\ 005[6 "5!C#\ 007[9 "09!C#\ 012[5 "4?!C#\ 018[5"6!C#\ 027[1 "3!C#\ 030[5 "5?!C#\ 038[6 "1?!C#\ 040[7 "4!C#\ 044[0 "09a!C#\ 045[1 "8a!C#\ 048[5 "C1O#[ MSm:z "rel[ int[#] 309 ðMŁ¦ "9[2#\ 260 "0[4#\ 200 "099#\ 170"27#\ 160 "09#\ 142 "7#[

Further elution with EtOAcÐHexane "5]0# gave abrown gum "299 mg#\ which on FC on silica gel "29 g#with EtOACÐhexane "5[4]0# gave 2 as a yellow semi!solid "33 mg#\ ðaŁD −4[34> "c 0[0#[ HRMS] m:z267[0720 ðM−H1OŁ¦[ Calcd for C13H15O3] 267[0720[UV lmax nm "log o#] 118 "3[09#\ 172 "3[99#\ 239 "3[08#[IR nmax cm−0] 2399\ 1899\ 0619\ 0489\ 0369[ 0H NMR"59 MHz#] d 0[02 "5H\ s\ 6?!Me and 7?!H#\ 0[30 "5H\s\ 7!Me#\ 0[53 "2H\ s\ 2?!Me#\ 1[53 "1H\ m\ 3?!H#\ 3[72"0H\ d\ J � 00 Hz\ 0?!H#\ 3[75 "0H\ d\ J � 07 Hz\ 0?!H#\ 4[49 "1H\ m\ 4?! and 5?!H#\ 4[44 "0H\ d\ J � 09 Hz\6!H#\ 4[87 "0H\ d\ J � 8[4 Hz\ 2!H#\ 5[17 "0H\ dd\J � 07 and 00 Hz\ 1?!H#\ 5[43 "0H\ d\ J � 09 Hz\ 5!H#\ 6[84 "0H\ d\ J � 8[4 Hz\ 3!H#[ 02C NMR "49 MHz#]16[1 and 16[2 "6?!Me and 7?!C#\ 16[7 "2?!C#\ 18[5 "7!Me#\ 32[3 "3?!C#\ 34[2 "2?!C#\ 69[5 "6?!C#\ 66[2 "7!C#\096[7 "3a!C#\ 009[6 "0?!C#\ 001[1 "2a!C#\ 004[4 "4a!C#\007[8 "5!C#\ 010[2 "09!C#\ 012[5 "4?!C#\ 029[9 "6!C#\027[7 "3!C#\ 030[3 "5?!C#\ 037[5 "1?!C#\ 041[4 "4!C#\044[0 "09a!C#\ 045[5 "8a!C#\ 048[3 "C1O#[ MS m:z"rel[ int[#] 267 ðM−H1OŁ¦ "19#\ 252 "39#\ 186 "099#\184 "11#\ 170 "10#\ 118 "05# and 014 "11#[

4!Methoxy!7\7!dimethyl!09!"6!acetoxy!2\6!dimethyl!octa!0\4!dien!2!yl#!1H\7H!benzoð0\1!b ]4\3!bŁdipyran!1!one "3#[ The coumarin "1# "099 mg# in dry pyridine"0 ml# was re~uxed with Ac1O "0 ml# at 009> for 13 h[Work!up\ followed by prep TLC "CH1Cl1#\ gave 3 asa colourless oil "49 mg#[ ðaŁD −0[6>[ HRMS] 341[1088ðMŁ¦[ Calcd for C16H21O5] 341[1088[ IR nmax cm−0]2999\ 0629\ 0619\ 0509\ 0469\ 0339\ 0139[ 0H NMR"59 MHz#] d 0[20 and 0[23 "each 2H\ s\ 6?!Me and 7?!H#\ 0[37 "5H\ bs\ 7!Me#\ 0[62 "2H\ s\ 2?!Me#\ 0[75 "2H\s\ !OAc#\ 1[3Ð2[1 "1H\ m\ w0:1 � 04 Hz\ 3?!H#\ 2[73

"2H\ s\ 4!OMe#\ 3[82 "0H\ dd\ J � 09[4 and 0 Hz\ 0?!H#\ 3[84 "0H\ dd\ J � 06 and 0 Hz\ 0?!H#\ 4[38 and4[41 "each 0H\ m\ w0:1 � 01 and 5 Hz\ 4?! and 5?!H#\4[60 "0H\ d\ J � 8[4 Hz\ 6!H#\ 5[08 "0H\ d\ J � 8[5 Hz\2!H#\ 5[39 "0H\ dd\ J � 06 and 09[4 Hz\ 1?!H#\ 5[59"0H\ d\ J � 8[4 Hz\ 5!H#\ 6[89 "0H\ d\ J � 8[5 Hz\ 3!H#[ MS m:z "rel[ int[#] 341 ðMŁ¦ "8#\ 326 "4#\ 281 "14#\266 "16#\ 238 "05#\ 200 "099#\ 186 "29#\ 170 "24#\ 160"08#[

4 !Methoxy!7\7!dimethyl!09!"2\6!dimethyl!0\4\6!trien!2yl#!1H\7H!benzoð0\1!b ]4\3!bŁdipyran!1 one "4#[Coumarin "1# "49 mg# in dry pyridine "1 ml#\ p!TsCl"14 mg# and dimethylaminopyridine "3 drops# werere~uxed at 014> for 04 h\ worked!up with CH1Cl1 andpuri_ed by FC with EtOAcÐhexane "2]6# to give 4 asan oil "04 mg#[ HRMS] 281[0875 ðMŁ¦[ Calcd forC14H17O3] 281[0877[ ðaŁD −1[8> "c 9[6#[ UV] lmax "nm\log o#] 102 "3[16#\ 160 "3[00#\ 216 "2[82#[ IR nmax "cm−0#]2999\ 0609\ 0509\ 0649\ 0339\ 0139\ 0049[ 0H NMR"59 MHz#] d 0[39 and 0[34 "each 2H\ s\ 7!Me#\ 0[57"5H\ bs\ 2?!and 6?!Me#\ 1[52 and 1[89 "each\ 0H\ dd\J � 02[4 and 6 Hz\ 3?!H#\ 2[65 "2H\ s\ 4!OMe#\ 3[61"1H\ m\ w0:1 � 2 Hz\ 7?!H#\ 3[73 "0H\ dd\ J � 00 and0 Hz\ 0?!H#\ 3[76 "0H\ dd\ J � 04 and 0 Hz\ 0?!H#\ 4[32"0H\ d\ J � 06 Hz\ 5?!H#\ 4[47 "0H\ d\ J � 09 Hz\ 6!H#\ 5[97 "0H\ d\ J � 8[4 Hz\ 2H#\ 5[09 "0H\ dt\ J � 06and 6 Hz\ 4?!H#\ 5[05 "0H\ dd\ J � 00 and 19 Hz\ 1?!H#\ 5[37 "0H\ d\ J � 09 Hz\ 5!H# and 6[61 "0H\ d\J � 8[4 Hz\ 3!H#^ MS m:z "rel[ int[#] 281 ð M¦Ł "6#\266 "09#\ 200 "099#\ 170 "21#\ 142 "02#[

5 ! "2!Carboxyethenyl# !4!methoxy!1\1\7\8!tetra !methyl!8!"3?!methyl!3?!hydroxypent!2?!enyl#!1H!furoð1\2!hŁchromene "5#[ Coumarin "1# "027 mg# in MeOH"5 ml# was stirred with aq[ NaOH "19)\ 2 ml# at 14>for 01 h[ Neutralisation "1 N HCl#\ followed by work!up\ gave a crude product\ which on FC withCH1Cl1]MeOH "38]0# gave 5 "079 mg# as yellow cys!tals from CH1Cl1Ðhexane\ mp 63>[ ðaŁD −05[0> "c 9[5#["HRMS] 317[1086 ðMŁ¦[ Calcd for C14H21O5]317[1088#[ UV] lmax nm "log o#] 173 "2[34#\ 160 "2[49#\111 "3[11#[ IR] nmax cm−0] 2999\ 0699\ 0509\ 0489\ 0339\0119\ 0019[ 0H NMR "59 MHz#] d 0[05 "2H\ s\ 8!Me#\0[19 "2H\ d\ J � 6 Hz\ 7!Me#\ 0[15 "5H\ s\ 3?!Me and4?!H#\ 0[30 "5H\ s\ 1!Me#\ 1!1[8 "1H\ m\ 0?!H#\ 2[57"2H\ s\ 4!OMe#\ 3[59 "0H\ q\ J � 6 Hz\ 7!H#\ 4[39 "0H\d\ J � 8[4 Hz\ 6!H#\ 4[35 "0H\ d\ J � 8 Hz\ 2!H#\ 4[46"1H\ m\ w0:1 � 3 Hz\ 1?!H\ 2?!H#\ 4[84 "0H\ d\ J � 01Hz\ 1?!H#\ 5[75 "0H\ d\ J � 01 Hz\ 0?!H#[ MS m:z "rel[int[#] 317 ðMŁ¦ "00#\ 302 "04#\ 284 "4#\ 218 "099#\ 188"13#\ 174 "49#\ 158 "29#\ 128 "29#[

Methylation of 2[ Coumarin 2 "13 mg# on stirringwith excess CH1N1ÐEt1O at 14> for 1 h[ gave 1 "19mg#\ identical with that isolated above[

Acknowled`ements*We wish to thank Dr JohnMacLeod of the Research School of Chemistry\ Aus!tralian National University\ Canberra for his assist!ance in obtaining high resolution MS data[ Financialassistance from SAREC\ Sida and IPICS\ UppsalaUniversity\ is gratefully acknowledged[

V[ KUMAR et al[107

REFERENCES

0[ A Revised Handbook to the Flora of Ceylon\ Vol[V\ ed[ M[ D[ Dassanayake and F[ R[ Fosberg[Amerind\ New Delhi\ 0874[

1[ Kumar\ V[\ Niyaz\ N[ M[\ Wickramaratne\ D[ B[

M[ and Balasubramaniam\ S[\ Phytochemistry\0880\ 29\ 0120[

2[ Kumar\ V[\ Niyaz\ N[ M[ and Wickramaratne\ D[B[ M[\ Phytochemistry\ 0884\ 27\ 794[

3[ Dictionary of Or`anic Compounds\ ed[ I[ M[ Heil!bron and H[ M[ Bunbury[ Eyre and Spottiswoode\London\ 0854[