Nahocols and isonahocols, endothelin antagonists from the brown alga, sargassum autumnale

\

Phytochemistry\ Vol[ 37\ No[ 5\ pp[ 0992Ð0900\ 0887 Þ 0887 Elsevier Science Ltd[ All rights reserved Printed in Great Britain 9920Ð8311:87 ,08[99¦9[99

Pergamon PII] S9920Ð8311"86#99365Ð6

NAHOCOLS AND ISONAHOCOLS\ ENDOTHELIN ANTAGONISTS FROM THE BROWN ALGA\ SARGASSUM AUTUMNALE NAOKO TSUCHIYA\ AIYA SATO\ HIDEYUKI HARUYAMA$\ TOHRU WATANABE% and YASUTERU IIJIMA% Biomedical Research Laboratories\ $Analytical and Metabolic Research Laboratories\ and %Pharmacology and Molecular Biology Research Laboratories\ Sankyo Co[ Ltd[ 1!47 0!chome\ Shinagawa!ku\ Tokyo 039!9994\ Japan "Received in revised form 10 April 0886#

Key Word Index*Sar`assum autumnale^ Sargassaceae^ brown alga^ nahocols^ isonahocols^ aryl prenyl ether^ prenyl hydroquinone^ endothelin antagonists[

Abstract*Novel endothelin antagonists\ nahocols A\ A0\ B\ C\ D0 and D1\ and isonahocols D0 and D1\ were isolated from the brown alga\ Sar`assum autumnale[ Their structures were determined through detailed analysis of NMR spectra and chemical reactions[ Nahocols have an aryl prenyl ether structure\ which are speculated to be biogenetic precursors of the ubiquitous prenyl hydroquinones or prenyl benzoquinones in the plant and animal kingdoms[ Þ 0887 Elsevier Science Ltd[ All rights reserved

INTRODUCTION

Endothelin "ET!0# ð0Ł is an endothelium!derived 10! amino acid peptide[ It has a very potent vaso! constriction activity in isolated blood vessels and con! stitutes an ET family with its two isoforms\ ET!1 and ET!2\ and four highly homologous cardiotoxic peptides\ sarafotoxin S5aÐd[ ET has speci_c binding! sites on many cell membranes\ such as smooth muscle and the endothelial and epithelial cells of many organs[ The binding!sites have been grouped into two subtypes\ ETA and ETB based on ligand a.nity[ The obvious increase of ET!0 blood levels has been clini! cally observed in various diseases\ including acute renal insu.ciency\ acute myocardial infarction\ hypertension and arteriosclerosis[ ET receptor antag! onists may therefore be e}ective for the prevention and treatment of these diseases[ A variety of natural and synthetic antagonists ð1Ł has been found\ some of these are in clinical trials[ In the course of a programme for investigating new ET antagonists in marine organisms\ we screened extracts of marine organisms for inhibition of ET!0 binding to its receptors "ETA and ETB# and found that the brown alga\ Sar`assum autumnale\ produced endothelin antagonists ð2Ł[ We herein report on the isolation\ characterization and antagonistic activities of the novel antagonists "0aÐf\ 1aÐb#[ Sar`assum aut! umnale is a relatively rare brown alga\ found in shal! low and protected waters of limited coasts washed by the Tsushima Current[ Of great biological interest is

 Author to whom correspondence should be addressed[

that S[ autumnale matures in summer\ while most other brown algae belonging to this taxon\ mature in early spring through early summer in Japan[

RESULTS AND DISCUSSION

Sar`assum autumnale was air!dried\ powdered and extracted with methanol at room temperature[ The methanol extract was partitioned between hexane and 89) aqueous methanol[ The antagonistic activity remained in the 89) aqueous methanol fraction\ con! taining a complex mixture of closely related compounds[ The 89) aqueous methanol extract was repeatedly separated by a combination of normal and reversed!phase chromatography guided by endothelin binding assay ð3Ł[ Nahocol A "0a#\ a colourless oil\ analysed for C18H31O5 by HREI mass spectrometry "ðMŁ¦ m:z 375[2990\ D ¦0[8 mmu#[ The IR indicated the pres! ence of hydroxyl "2349 cm−0#\ an ester "0629 cm−0# and carbonyl "0694 cm−0#[ The 0H NMR "Table 0# was consistent with the presence of a secondary\ a tertiary and three ole_nic methyls\ a proton on each carbon bearing an oxygen atom\ _ve ole_nic protons\ a methoxyl\ an isolated methylene and a trisubstituted aromatic ring[ In the 02C NMR "Table 0#\ signals assignable to 04 sp2 and 03 sp1 carbons were observed[ The sp2 carbons contained six methyls\ six methylenes\ two tertiary and a quaternary one[ The sp1 carbons comprised two trisubstituted double bonds\ a vinyl double bond and the trisubstituted aromatic ring\ in addition to the ketone and ester carbonyls[ 0a was converted to a diacetate "2a# and a methyl ether "2b#\

0992

0993

N[ TSUCHIYA et al[

Fig[ 0[ Structures of nahocols and their derivatives[

respectively\ compatible with the presence of a sec! ondary and a phenolic hydroxyl[ Treatment of 2a with dilute NaOH transposed the carbonyl from C!01? to C!02? to yield a diastereomeric mixture of 3a and 3b[ HMQC and relayed COSY experiments indicated the presence of 09 substructures "AÐJ# "Fig[ 1#[ Three protons at d 1[57 "H!00?#\ 3[75 "H!02?# and 0[94 "H! 08?# showed cross!peaks with C!01 at d 103[5\ sug!

gesting the connectivities of A\ B and C[ The proton "H!00?# also showed a cross!peak with C!8? "d 14[2#\ consistent with the connectivity of C and D[ The con! nectivity of D and E was supported by the long!range couplings of H!5? "d 4[94# and H!07? "d 0[44# to C!7? "d 28[3#[ The proton "H!07?# coupled to C!1? "d 032[5# and C!3? "d 31[9#\ and three vinyl protons ðd 4[06\ 4[07 "H!0?#\ 5[93 "H!1?#Ł also coupled to C!2? "d 70[6#[ These H!C correlations were compatible with the con! nectivity of EÐG[ Substructures "HÐJ# constituted a 1\4!dihydroxyphenylacetic acid "homogenistic acid# moiety\ any of whose hydroxyls made an ether linkage with F[ In the NOESY experiment\ NOEs were observed between an aromatic proton "H!2# and H!0?\ 3? and 06? "Fig[ 1#\ thus indicating that C!2? was connected to C!1 through an ether linkage\ because two aromatic protons must show NOE if the alternative ether link! age at C!4 is correct[ Nahocol!A\ consequently\ could be depicted as methyl 4!hydroxy!1!"O#!ð02?!hydroxy!

Table 0[ 0H and 02C NMR data of compounds 0a and 0b "CDCl2# 0a No[

02

Cd

0 1 2 3 4 5 0?

016[1 "C# 037[8 "C# 008[6 "CH# 003[0 "CH# 038[8 "C# 006[6 "CH# 003[1 "CH1#

1? 2? 3? 4?

032[5 "CH# 70[6 "C# 31[9 "CH1# 11[2 "CH1#

5? 6? 7?

015[3 "CH# 023[5 "C# 28[3 "CH1#

8?

14[2 "CH1#

09?

22[5 "CH1#

00? 01? 02? 03? 04? 05? 06? 07? 08? 19? 0ý

30[2 "CH# 103[5 "C# 63[2 "CH# 010[0 "CH# 028[8 "C# 14[8 "CH2# 11[4 "CH2# 04[6 "CH2# 05[0 "CH2# 07[5 "CH2# 25[3 "CH1#

1ý OMe

061[2 "C# 40[7 "CH2#

 Disappeared with D1O[

0b H d ðJ "Hz#Ł

0

0

5[80 "d\ 7[7# 5[46 "dd\ 2[3\ 7[7#

5[82 "d\ 8[9# 5[48 "dd\ 1[8\ 8[9#

5[57 "d\ 2[3# 4[06 "dd\ 9[8\ 00[1# 4[07 "dd\ 9[8\ 06[5# 5[93 "dd\ 00[1\ 06[5#

5[58 "d\ 1[8# 4[07 "dd\ 0[9\ 00[0# 4[08 "dd\ 0[9\ 07[3# 5[94 "dd\ 00[0\ 07[3#

0[61 "m# 1[96 "m# 1[96 "m# 4[98 "t\ 6[9#

0[61 "m# 1[98 "m# 1[98 "m# 4[98 "t\ 5[7#

0[83 "t\ 5[7# 0[83 "t\ 5[7# 0[21 "m# 0[21 "m# 0[21 "m# 0[47 "m# 1[57 "sixt[ 5[7#

0[81 "t\ 5[7# 0[81 "t\ 5[7# 0[1Ð0[3 "m# 0[1Ð0[3 "m# 0[1Ð0[3 "m# 0[4Ð0[6 "m# 1[57 "sixt[ 5[7#

3[75 "dd\ 2[8\ 8[7# 3[87 "ddd\ 0[9\ 0[4\ 8[7#

3[82 "br d\ 8[6# 3[85 "br d\ 8[6#

0[79 "d\ 0[9# 0[25 "s# 0[44 "s# 0[94 "d\ 5[7# 0[75 "d\ 0[4# 2[44 "d\ 05[1# 2[50 "d\ 05[1#

0[70 "br s# 0[27 "s# 0[45 "s# 0[09 "d\ 5[7# 0[76 "br s# 2[44 "d\ 05[0# 2[50 "d\ 05[0#

2[57 "s#

2[58 "s#

H d ðJ "Hz#Ł

Aryl phenyl esters from Sar`assum autumnale

0994

Fig[ 3[ Structures of acetonides[

Fig[ 1[ Substructures of compound 0a and their HMBC and NOE correlations[

Fig[ 2[ Substructures of compounds 0cÐf correlated by HMBC[

01?!oxo!2?\6?\00?\04?!tetramethyl!0?\5?"E#\03?!hexade! catrien!2?!ylŁphenylacetate "0a#[ The relative and absolute con_gurations at C!2?\!00? and !02? remain unclear[ Nahocol!A0 "0b#\ a colourless oil\ analysed for C18H31O5\ isomeric to 0a\ by HREI mass spectrometry "ðMŁ¦ m:z 375[1880\ D ¦9[8 mmu#[ The IR indicated the presence of hydroxyl "2599 and 2249 cm−0#\ ester "0629 cm−0# and carbonyl "0609 cm−0#[ The 0H NMR of 0b also closely resembled 0a "Table 0#\ indicating that they shared the same planar structure[ They were\ however\ stereoisomeric to each other at C!2?\ !00? or ! 02?[ Nahocol!B "0c#\ a colourless oil\ analysed for C18H31O4 by HREI mass spectrometry "ðMŁ¦ m:z 369[2908\ D −0[2 mmu#[ Although the spectral fea! tures were closely related to those of 0a\ the 0H and 02 C NMR suggested a substructure K\ in which the hydroxyl at C!02? of 0a was replaced by a hydrogen atom[ The diagnostic cross!peak between H!02? "d 2[03# and C!01? "d 102[7#\ together with other cross! peaks "Fig[ 2#\ were observed in the HMBC experi! ment[ Therefore\ nahocol!B could be assigned as methyl 4!hydroxy!1!"O#!ð01?!oxo!2?\6?\00?\04?!tetram ethyl!0?\5?"E#\03?!hexadecatrien!2?!ylŁphenyl! acetate "0c#[ Nahocol!C "0d#\ a colourless oil\ analysed for C18H33O5 by HREI mass spectrometry "ðM!H1OŁ¦ m:z 369[2906\ D −0[4 mmu# and had no carbonyl[ The DQFCOSY spectrum indicated the presence of a sub! structure L "Fig[ 2#\ in addition to EÐJ[ The HMBC could connect them to methyl 1!"O#!ð01?\02?!dihy! droxy!2?\6?\00?\04?!tetramethyl!0?\5?"E#\03?!hexadeca!

trien!2?!ylŁ!4!hydroxyphenylacetate "0d#[ On treat! ment with acetone dimethyl acetal in the presence of p!TsOH\ 0d gave a cis!acetonide "4a# "Fig[ 3#\ whose stereochemistry was assigned by NOE ð4Ł between H! 01? "d 2[79# and H!02? "d 3[67#[ The vicinal hydroxyls were therefore erythro to each other[ Nahocol!D0 "0e#\ and !D1 "0f#\ had the same molec! ular formula C18H31O5 determined by HREI mass spectrometry "0e] ðM!H1OŁ¦ m:z 357[1743\ D −1[1 mmu\ 0f] ðM!H1OŁ¦ m:z 357[1755\ D −0[9 mmu#\ and were diastereomeric to each other at C!01? or C!02?[ Although they resembled 0d in spectral features\ they were di}erent from 0d in the number of ole_nic methyls and double bonds] four methyls and four double bonds for 0e and 0f and three methyls and three double bonds for 0d[ The chemical shifts and splitting patterns ð0e] d 2[76 "d\ J  5[7 Hz#\ 0f] d 2[70 "d\ J  6[7 Hz#Ł of each H!01?\ which were related to C!00?\ !01? and !08? by HMBC "Fig[ 2#\ indicated that the double bond was located between C!09? and C! 00?\ and 0e and 0f could be assigned as diastreoisomers of methyl 1!"O#!ð01?\02?!dihydroxy!2?\6?\00?\04?!tetra! methyl!0?\5?"E#\09?"E#\03?!hexadecatetraen!2?!ylŁ!4! hydroxy phenylacetate[ 0e and 0f also gave cis! "4c# and trans! "4b# acetonides "Fig[ 3#\ respectively\ whose stereochemistry were determined by the respective NOEs between H!01? "d 3[42# and H!02? "d 3[83#\ H! 01? "d 2[86# and H!03? "d 4[06# and H!02? "d 3[34# and H!08? "d 0[55#[ Therefore\ 0e was erythro while 0f was threo[ Isonahocol D0 "1a# and isonahocol D1 "1b# could not be separated by HPLC on ODS and silica gel with a combination of solvents[ They could be only successful puri_ed by normal phase HPLC using nitrated silica gel\ NO1 with 09) i!propanol in hexane[ Isonahocol D0 "1a#\ a colourless oil\ had a molecular formula C18H31O5 "HREI mass spectrum ðM!H1OŁ¦

Fig[ 4[ Structures of compounds 1a and 1b[

0995

N[ TSUCHIYA et al[ Table 1[ 0H and 02C NMR data of compounds 0c and 0d "CDCl2# 0c

No[

02

Cd

0 1 2 3 4 5 0?

015[8 "C# 036[5 "C# 008[6 "CH# 003[0 "CH# 049[2 "C# 006[7 "CH# 003[1 "CH1#

1? 2? 3?

032[5 "CH# 70[5 "C# 31[0 "CH1#

4?

11[2 "CH1#

5? 6? 7?

013[2 "CH# 023[8 "C# 28[5 "CH1#

8?

14[4 "CH1#

09?

21[5 "CH1#

00? 01? 02? 03? 04? 05? 06? 07? 08? 19? 0ý

33[6 "CH# 102[7 "C# 30[9 "C# 005[9 "CH# 024[4 "C# 14[6 "CH2# 11[4 "CH2# 04[6 "CH2# 05[3 "CH2# 07[4 "CH2# 25[2 "CH1#

1ý OMe

061[6 "C# 40[7 "CH2#

0d 0

H d ðJ "Hz#Ł

5[80 "d\ 8[9# 5[47 "dd\ 2[9\ 8[9# 5[57 "d\ 2[9# 4[06 "dd\ 0[9\ 00[1# 4[07 "dd\ 0[9\ 06[2# 5[93 "dd\ 00[1\ 06[2# 0[64 "m# 0[64 "m# 1[09 "m# 1[09 "m# 4[09 "t\ 6[9# 0[83 "t\ 6[9# 0[83 "t\ 6[9# 0[25 "m# 0[25 "m# 0[20 "m# 0[53 "m# 1[57 "m# 2[03 "d\ 5[7# 4[18 "t\ 5[7# 0[64 "br s# 0[25 "s# 0[44 "s# 0[95 "d\ 5[7# 0[79 "br s# 2[44 "d\ 05[9# 2[50 "d\ 05[9# 2[57 "s#

Fig[ 5[ Substructures of compounds 1a and 1b correlated by HMBC and NOE[

m:z 357[1773\ D −9[7 mmu# and its 0HÐ0H COSY and 0HÐ02C COSY spectra indicated the presence of a substructure N\ in addition to E and M[ The cross! peaks of H!0? with C!0\ !1 and !5 in the HMBC were consistent with N "Fig[ 5#[ The Z!con_guration of the C!1ÐC!2\ double bond was determined by NOEs[ 1a was therefore depicted as methyl 1\4!dihydroxy!2! ð01?\02?!dihydroxy!2?\6?\00?\04?!tetramethyl!1?"Z#\5? "E#\09?"E#\03?!hexadecatetraen!0?!ylŁphenylacetate[ Isonahocol D1 "1b# had the same molecular formula C18H31O5 "HREI mass spectrometry ðM!H1OŁ¦ m:z

02

Cd

016[0 "C# 037[9 "C# 008[6 "CH# 003[0 "CH# 038[8 "C# 006[6 "CH# 003[1 "CH1# 032[6 "CH# 70[6 "C# 30[8 "CH1# 11[2 "CH1# 013[9 "CH# 024[2 "C# 28[7 "CH1# 14[0 "CH1# 21[8 "CH1# 23[1 "CH# 66[0 "CH# 58[4 "CH# 012[2 "CH# 027[4 "C# 15[9 "CH2# 11[5 "CH2# 04[7 "CH2# 03[2 "CH2# 07[4 "CH2# 25[2 "CH1# 061[3 "C# 40[8 "CH2#

0

H d ðJ "Hz#Ł

5[80 "d\ 8[9# 5[46 "dd\ 2[9\ 8[9# 5[57 "d\ 2[9# 4[07 "dd\ 0[9\ 00[1# 4[08 "dd\ 0[9\ 06[3# 5[94 "dd\ 00[1\ 06[3# 0[64 "m# 0[64 "m# 1[96 "m# 1[96 "m# 4[98 "t\ 5[7# 0[81 "t\ 5[7# 0[81 "t\ 5[7# 0[20 "m# 0[35 "m# 0[08 "m# 0[24 "m# 0[54 "m# 2[34 "t\ 4[3# 3[28 "dd\ 4[3\ 8[2# 4[23 "d\ 8[2# 0[66 "br s# 0[26 "s# 0[45 "s# 9[85 "d\ 5[7# 0[62 "br s# 2[44 "d\ 05[0# 2[50 "d\ 05[0# 2[57 "s#

357[1769\ D −9[4 mmu# as 1a[ The NOEs in a sub! structure O "Fig[ 5#\ in addition to other spectral properties\ showed that 1b di}ered from 1a in the stereochemistry of the C!1ÐC!2\ double bond\ and could be depicted as methyl 1\4!dihydroxy!2!ð01?\02?! dihydroxy ! 2?\6?\00?\04? ! tetramethyl ! 1?"E#\5?"E#\09? "E#\03!hexadecatetraen!0?!ylŁphenylacetate[ The vicinal hydroxyls of 1a and 1b were both erythro based on the formation of the corresponding cis!acetonides "5a\ b# "Fig[ 3#[ Many Sar`assums ð4Ð00Ł and their relatives ð00Ð02Ł frequently produce prenyl hydroquinones or prenyl benzoquinones\ while S[ autumnale contains nahocols\ with an aryl prenyl ether structure\ and isonahocols with a prenyl hydroquinone one[ It may be speculated that the latter are biosynthesized through Claisen rearrangement of the former[ Some isonahocol!type metabolites of 0aÐf were found in the extract\ but they have not yet been puri_ed[ Attempts to rearrange 0e to 1a chemically did not succeed because of their

Aryl phenyl esters from Sar`assum autumnale

0996

Table 2[ 0H and 02C NMR data of compounds 0e and 0f "CDCl2# 0e No[

02

0f 0

Cd

H d ðJ "Hz#Ł

0 1 2 3 4 5 0?

016[1 "C# 037[9 "C# 008[6 "CH# 003[0 "CH# 038[8 "C# 006[6 "CH# 003[1 "CH1#

1? 2? 3?

032[5 "CH# 70[6 "C# 30[8 "CH1#

4?

11[2 "CH1#

5? 6? 7?

013[5 "CH# 023[7 "C# 28[0 "CH1#

8?

15[9 "CH1#

09? 00? 01? 02? 03? 04? 05? 06? 07? 08? 19? 0ý

018[3 "C# 022[6 "C# 79[1 "CH# 58[2 "CH# 012[4 "CH# 028[9 "C# 15[9 "CH2# 11[4 "CH2# 04[7 "CH2# 00[8 "CH2# 07[5 "CH2# 25[2 "CH1#

1ý OMe

061[6 "C# 40[7 "CH2#

5[80 "d\ 8[9# 5[46 "dd\ 2[9\ 8[9# 5[56 "d\ 2[9# 4[05 "dd\ 0[9\ 00[1# 4[06 "dd\ 0[9\ 06[2# 5[93 "dd\ 00[1\ 06[2# 0[58 "m# 0[58 "m# 1[98 "m# 1[98 "m# 4[00 "t\ 6[9# 1[99 "t\ 6[9# 1[99 "t\ 6[9# 1[04 "m# 1[04 "m# 4[36 "t\ 5[7# 2[76 "d\ 5[7# 3[20 "dd\ 5[7\ 7[7# 4[08 "t\ 7[7# 0[67 "br s# 0[25 "s# 0[47 "s# 0[55 "s# 0[62 "br s# 2[44 "d\ 05[9# 2[50 "d\ 05[9# 2[57 "s#

instability under the reaction conditions[ In addition\ we are uncertain if nahocols and isonahocols are nat! urally occurring or obtained by esteri_cation of the corresponding carboxylic acids during methanolic extraction[ Endothelin antagonistic activities of the nahocols and isonahocols are listed in Table 4[ Although they are not always potent and selective\ they appeared to be somewhat ETB!selective[ EXPERIMENTAL

General[ 0H "399 MHz# and 02C NMR "099 MHz# were recorded in CDCl2 with TMS as an int[ standard[ IR were recorded in CHCl2[ UV and optical rotations were recorded in EtOH[ Silica gel "129Ð399 mesh# and packed Lobar columns ðSi!59 "normal phase# and RP! 07 "reversed!phase#Ł were used for low pressure CC or TLC[ Packed columns "19f×149 mm# of silica gel\ NO1 and ODS were used for prep[ HPLC[

02

Cd

016[0 "C# 037[9 "C# 008[6 "CH# 003[0 "CH# 038[8 "C# 006[6 "CH# 003[1 "CH1# 032[5 "CH# 70[6 "C# 30[8 "CH1# 11[3 "CH1# 013[3 "CH# 023[7 "C# 28[0 "CH1# 15[9 "CH1# 017[6 "CH# 022[6 "C# 70[9 "CH# 69[1 "CH# 012[5 "CH# 027[4 "C# 14[8 "CH2# 11[5 "CH2# 04[7 "CH2# 01[3 "CH2# 07[4 "CH2# 25[2 "CH1# 061[3 "C# 40[8 "CH2#

0

H d ðJ "Hz#Ł

5[80 "d\ 8[9# 5[47 "dd\ 2[9\ 8[9# 5[57 "d\ 2[9# 4[05 "dd\ 0[9\ 00[0# 4[07 "dd\ 0[9\ 06[3# 5[94 "dd\ 00[0\ 06[3# 0[69 "m# 0[69 "m# 1[96 "m# 1[96 "m# 4[00 "t\ 6[9# 0[88 "t\ 6[5# 0[88 "t\ 6[5# 1[00 "m# 1[00 "m# 4[39 "dd\ 4[8\ 6[2# 2[70 "d\ 6[7# 3[18 "dd\ 6[7\ 7[2# 4[02 "d\ 7[2# 0[60 "br s# 0[26 "s# 0[46 "s# 0[59 "s# 0[57 "br s# 2[44 "d\ 05[9# 2[50 "d\ 05[9# 2[57 "s#

Plant material[ Sar`assum autumnale was collected in shallow water "0 m deep# at the end of Omosu Bay\ Okino Shima\ Shimane Pref[\ Japan\ in June 0880[ It was authenticated by Prof[ M[ Kajimura of Oki Mar! ine Biological Experimental Station\ Shimane Uni! versity\ where a voucher specimen is kept[ Extraction and isolation[ The alga "2[4 kg#\ after washing\ was air!dried\ powdered and extracted ×2 with MeOH "19 l# at room temp[ The combined extracts were concd to dryness under red[ pres[ and then partitioned between hexane and 89) aq[ MeOH[ Concn of the active 89) aq[ MeOH layer under red[ pres[\ left a brown oil "039 g#[ Sepn was monitored by inhibition of each fr[ against ET!0 binding to a porcine lung ETB receptor ð3Ł[ The 89) aq[ MeOH extract "019 g# was subjected to silica gel CC "0[1 kg#[ Elution with a 09) gradient mixt[ of EtOAc in hexane gave Fr!0 "19Ð29) EtOAc\ 21[76 g\ 48) inhibition at 09 mg m−0#\ Fr!1 "19Ð29) EtOAc\ 8[83 g\ 099) inhi! bition at 09 mg m−0#\ Fr!2 "29Ð39) EtOAc\ 04[90

0997

N[ TSUCHIYA et al[ Table 3[ 0H and 02C NMR data of compounds 1a and 1b "CDCl2# 1a

No[

02

Cd

0 1 2 3 4 5 0?

010[6 "C# 035[5 "C# 020[9 "C# 005[9 "CH# 038[2 "C# 004[0 "CH# 17[8 "CH1#

1? 2? 3?

011[5 "CH# 026[3 "C# 20[7 "CH1#

4?

15[1 "CH1#

5? 6? 7?

013[5 "CH# 023[7 "C# 28[9 "CH1#

8?

14[6 "CH1#

09? 00? 01? 02? 03? 04? 05? 06? 07? 08? 19? 0ý

018[8 "CH# 022[4 "C# 79[3 "CH# 58[2 "CH# 012[3 "CH# 028[4 "C# 15[0 "CH2# 12[3 "CH2# 04[7 "CH2# 00[7 "CH2# 07[5 "CH2# 26[3 "CH1#

1ý OMe

063[9 "C# 41[5 "CH2#

1b 0

02

0

5[45 "d\ 2[9#

016[0 "C# 035[6 "C# 037[9 "C# 005[9 "CH# 038[2 "C# 004[0 "CH# 18[0 "CH1#

5[45 "d\ 2[9#

H d ðJ "Hz#Ł

5[35 "d\ 2[9# 2[21 "d\ 5[7# 2[21 "d\ 5[7# 4[23 "t\ 5[7# 1[06 "m# 1[06 "m# 1[02 "m# 1[02 "m# 4[01 "t\ 5[2# 1[94 "m# 1[94 "m# 1[19 "m# 1[19 "m# 4[35 "t\ 5[7# 2[75 "d\ 5[7# 3[20 "dd\ 5[7\ 7[7# 4[08 "t\ 7[7# 0[66 "s# 0[63 "s# 0[59 "s# 0[55 "s# 0[62 "s# 2[48 "s# 2[48 "s# 2[62 "s#

Table 4[ Endothelin antagonistic activities of nahocols\ ison! ahocols\ and their derivatives Antagonistic activities "mM# Compounds ETA "Bovine arota# ETB "Porcine lung# 0a 0b 0c 0d 0e 0f 1a 1b 2a 3a 3b

65[0 73[2 78[2 71[2 099[7 67[0 001[6 099[9 ×2499 041[4 041[4

10[5 16[6 12[3 16[0 18[3 16[6 07[4 08[0 ×249 092[7 090[5

g\ not tested#\ Fr!3 "39Ð49) EtOAc\ 29[89 g\ 56) inhibition at 09 mg ml−0#\ Fr!4 "49Ð59) EtOAc\ 00[29 g#\ Fr!5 "59Ð89) EtOAc\ 15[44 g\ 099) inhibition at

Cd

018[0 "CH# 026[1 "C# 28[4 "CH1# 15[0 "CH1# 013[3 "CH# 023[7 "C# 28[0 "CH1# 15[1 "CH1# 029[9 "CH# 022[4 "C# 79[3 "CH# 58[2 "CH# 012[4 "CH# 028[3 "C# 15[0 "CH2# 12[3 "CH2# 04[8 "CH2# 00[7 "CH2# 07[5 "CH2# 26[2 "CH1# 063[9 "C# 41[5 "CH2#

H d ðJ "Hz#Ł

5[35 "d\ 2[9# 2[22 "d\ 5[7# 2[22 "d\ 5[7# 4[18 "t\ 5[7# 1[04 "m# 1[04 "m# 1[01 "m# 1[01 "m# 4[09 "t\ 5[7# 1[90 "m# 1[90 "m# 1[06 "m# 1[06 "m# 4[35 "t\ 5[7# 2[74 "d\ 5[7# 3[29 "dd\ 5[7# 4[19 "d\ 7[7# 0[67 "s# 0[66 "s# 0[48 "s# 0[54 "s# 0[63 "s# 2[59 "s# 2[59 "s# 2[62 "s#

09 mg ml−0#\ Fr!6 "EtOAc\ 6[40 g\ 75) inhibition at 09 mg ml−0# and Fr!7 "09Ð29) MeOH in EtOAc\ 01[03 g\ 24) inhibition at 09 mg ml−0#[ Fr!1 was subjected to silica gel CC "299 g#\ eluted with 14) EtOAc in hexane to yield Fr!1!0 "2[749 g#\ Fr!1!1 "0[231 g#\ Fr!1!2 "1[473 g# and Fr!1!4 "1[532 g#[ The combined frs Fr!1!1 and Fr!1!2 were again chromatographed on silica gel "079 g#[ Elution with CHCl2\ followed by a combination of CC ðSi!59 "14) Me1CO in hexane# and RP!07 "74) aq[ MeOH#Ł\ gave 0c "082[5 mg#[ Fr!3 "19 g# was subjected to silica gel CC "599 g#\ eluted stepwise with a mixt[ of EtOAc and hexane to give Fr!3!0 "29) EtOAc\ 223 mg\ 14) inhibition at 4 mg ml−0#\ Fr!3!1 "29Ð39) EtOAc\ 02[383 g\ 27Ð34) inhibition at 4 mg ml−0#\ Fr!3!2 "49) EtOAc\ 0[216 g\ 44[1) inhibition at 4 mg ml−0#\ Fr!3!3 "49Ð099) EtOAc\ 0[436 g\ 22Ð32) inhibition at 4 mg ml−0# and Fr!3!4 "49) MeOH in EtOAc\ 1[064 g\ 19[0) inhibition at 4 mg ml−0#[ Fr!3!1 "01[02 g# gave a major fr[ "6[106 g# after elution with 9[4) MeOH in CHCl2

Aryl phenyl esters from Sar`assum autumnale

on silica gel CC "0[1 kg#[ Prep[ HPLC "ODS\ 59) aq[ MeOH# gave a yellow oil "2[029 g# containing 0a and 0b[ This was subjected to RP!07 chromatography and elution with 69Ð79) aq[ MeOH gave 0a "805 mg# and a 0b!rich fr[ "75 mg#[ The latter was puri_ed by HPLC "silica gel 3) i!PrOH in hexane# to give 0b "12[8 mg#[ Fr!5 "0[71 g# was _rst subjected to CC ðRP!07\ 64) aq[ MeOH and Si!59 "04) i!PrOH in hexane#Ł\ the major fr[ from which was _nally puri_ed to 0e "040[5 mg# by RP!07 chromatography "49) aq[ ACN#[ The remainder "13[14 g# was subjected to silica gel CC "399 g×1# and eluted with 1[4) MeOH in CHCl2 to give Fr!5!0 "2[70 g#\ Fr!5!1 "0[21 g#\ Fr!5!2 "08[25 g#\ Fr! 5!3 "9[10 g#\ Fr!5!4 "0[91 g# and Fr!5!5 "0[04 g#[ Fr!5! 4 "0[91 g# was subsequently subjected to Si!59 "1) MeOH in CHCl2# and RP!07 chromatography "44) aq[ ACN# to give 0f "064 mg#[ Fr!5!2 "08[25 g# was separated by HPLC "ODS\ 49) aq[ ACN# into 09 frs ðFr!5!2!0 "186[6 mg#\ !1 "1[296 g#\ !2 "0[995 g#\ !3 "0[011 g#\ !4 "1[571 g#\ !5 "0e\ 401[7 mg#\ !6 "0[902 g#\ !7 "0[332 g#\ !8 "602 mg# and !09 "061 mg#Ł[ Fr!5!8 "602 mg# was further puri_ed to 0d "79[4 mg#\ 0e "35[1 mg# and 0f "32[3 mg# by CC ðRP!07 "59) aq[ ACN#\ Si!59 "CHCl2#Ł and HPLC "ODS\ 69) aq[ ACN#Ł[ Fr!5!1 "0[21 g# was subjected to RP!07 chromatography "49) aq[ ACN# and HPLC "NO1\ 09) i!PrOH in hexane# to give 1a "25[9 mg# and 1b "39[9 mg#[ Nahocol A "0a#[ Colourless oil[ ðaŁ14 D −057[6> "c 9[88#[ C18H31O5\ HREIMS "m:z# 375[2990 "ðMŁ¦\ D ¦0[8 mmu#[ IR "nmax cm−0# 2349\ 0629\ 0509\ 0489\ 0384\ 0359\ 0309\ 0279\ 0259\ 0119\ 0199\ 0054\ 0099\ 819[ UV ðlmax nm "log o#Ł 194 "3[2#\ 114 "2[7#\ 182 "2[2#[ 0 H and 02C NMR "Table 0#[ Nahocol A0 "0b#[ Colourless oil[ ðaŁ14 D ¦09[4> "c 9[67#[ C18H31O5\ HREIMS "m:z# 375[1180 "ðMŁ¦\ D ¦9[8 mmu#[ IR "nmax cm−0# 2599\ 2249\ 0629\ 0609\ 0409\ 0359\ 0339\ 0279\ 0249\ 0209\ 0119\ 0089\ 0099\ 0999\ 759[ UV ðlmax nm "log o#Ł 196 "3[4#\ 182 "2[2#[ 0H NMR "Table 0#[ Nahocol B "0c#[ Colourless oil[ ðaŁ14 D −8[6> "c 9[85#[ C18H31O4\ HREIMS "m:z# 369[2908 "ðMŁ¦\ D −0[2 mmu#[ IR "nmax cm−0# 2599\ 1814\ 0629\ 0599\ 0324\ 0397\ 0269\ 0239\ 0179\ 0054\ 0989\ 889[ UV ðlmax nm "log o#Ł 193 "3[3#\ 117 "2[8#\ 182 "2[3#[ 0H and 02C NMR "Table 0#[ Nahocol C "0d#[ Colourless oil[ ðaŁ14 D ¦5[2> "c 9[60#[ C18H33O5\ HREIMS "m:z# 369[2906 "ðM!H1OŁ¦\ D −0[4 mmu#[ IR "nmax cm−0# 2599\ 2249\ 0629\ 0694\ 0599\ 0384\ 0324\ 0309\ 0269\ 0239\ 0054[ UV ðlmax nm "log o#Ł 195 "3[1#\ 118 "2[7#\ 182 "2[2#[ 0H and 02C NMR "Table 1#[ Nahocol D0 "0e#[ Colourless oil[ ðaŁ14 D ¦1[5> "c 9[65#[ C18H31O5\ HREIMS "m:z# 357[1743 "ðM!H1OŁ¦\ D −0[4 mmu#[ IR "nmax cm−0# 2599\ 2249\ 0629\ 0509\ 0489\ 0384\ 0339\ 0069\ 0099\ 0909[ UV ðlmax nm "log o#Ł 195 "3[4#\ 117 "2[8#\ 182 "2[4#[ 0H and 02C NMR "Table 2#[ Nahocol D1 "0f#[ Colourless oil[ ðaŁ14 D ¦3[4> "c 9[84#[ C18H31O5\ HREIMS "m:z# 357[1755 "ðM!H1OŁ¦\ D −0[9 mmu#[ IR "nmax cm−0# 2599\ 2249\ 0629\ 0509\

0998

0489\ 0384\ 0339\ 0069\ 0099\ 0909[ UV ðlmax nm "log o#Ł 195 "3[3#\ 118 "2[8#\ 182 "2[3#[ 0H and 02C NMR "Table 2#[ Isonahocol D0 "1a#[ Colourless oil[ ðaŁ14 D ¦7[3> "c 9[72#[ C18H31O5\ HREIMS "m:z# 357[1773 "ðM!H1OŁ¦\ D ¦9[7 mmu#[ IR "nmax cm−0# 2599\ 2249\ 0609\ 0599\ 0359\ 0324\ 0264\ 0119\ 0039\ 0909[ UV ðlmax nm "log o#Ł 109 "3[3#\ 182 "2[4#[ 0H and 02C NMR "Table 3#[ Isonahocol D1 "1b#[ Colourless oil[ ðaŁ14 D ¦7[5> "c 1[78#[ C18H31O5\ HREIMS "m:z# 357[1769 "ðM!H1OŁ¦\ D −9[4 mmu#[ IR "nmax cm−0# 2599\ 2249\ 0609\ 0599\ 0359\ 0324\ 0264\ 0239\ 0119\ 0039\ 0099\ 0909[ UV ðlmax nm "log o#Ł 194 "3[5#\ 183 "2[4#[ 0H and 02C NMR "Table 3#[ Nahocol A0 diacetate "2a#[ To a soln of 0a "183[5 mg# in dry pyridine "9[4 ml#\ was added Ac1O "9[4 ml#[ The mixt[ was kept at room temp[ overnight[ The residue\ after usual work!up\ was puri_ed by Si!59 chromatography\ eluted with 29) EtOAc in hexane to give 2a "164 mg# as a colourless oil[ ðaŁ14 D −012[7> "c 9[66#[ C22H35O7\ HREIMS "m:z# 469[2073 "ðMŁ¦\ D −9[8 mmu#[ IR "nmax cm−0# 0629\ 0509\ 0389\ 0324\ 0269\ 0239\ 0119\ 0084\ 0099\ 0904\ 854\ 819[ UV ðlmax nm "log o#Ł 191 "3[3#\ 114 "2[7#\ 167 "1[8#[ 0H NMR] d 0[91 "2H\ d\ J  5[6 Hz#\ 0[13Ð0[4 "1H\ m#\ 0[33 "2H\ s#\ 0[4Ð0[7 "1H\ m#\ 0[71 "2H\ d\ J  0[1 Hz#\ 0[75 "2H\ d\ J  0[1 Hz#\ 0[85 "1H\ t\ J  6[4 Hz#\ 1[9Ð1[0 "1H\ m#\ 1[02 "2H\ s#\ 1[15 "2H\ s#\ 1[54 "0H\ sixtet\ J  5[7 Hz#\ 2[47 "0H\ d\ J  05[0 Hz#\ 2[51 "0H\ d\ J  05[0 Hz#\ 2[57 "2H\ s#\ 4[98 "0H\ t\ J  6[0 Hz#\ 4[03 "0H\ d\ J  00[0 Hz#\ 4[08 "0H\ d\ J  06[5 Hz#\ 4[10 "0H\ d\ J  09[9 Hz#\ 4[79 "0H\ d\ J  09[9 Hz#\ 5[95 "0H\ dd\ J  00[0\ 06[5 Hz#\ 5[72 "0H\ dd\ J  1[8\ 7[8 Hz#\ 5[81 "0H\ d\ J  1[8 Hz#\ 6[92 "0H\ d\ J  7[8 Hz#[ 02C NMR] d 04[6 "CH2#\ 05[1 "CH2#\ 07[8 "CH2#\ 19[7 "CH2#\ 10[0 "CH2#\ 11[1 "CH1#\ 11[5 "CH2#\ 14[2 "CH1#\ 15[9 "CH2#\ 22[0 "CH1#\ 25[4 "CH1#\ 28[5 "CH1#\ 31[0 "CH#\ 31[3 "CH#\ 40[7 "CH2#\ 64[8 "CH#\ 71[9 "CH#\ 003[4 "CH1#\ 005[8 "CH#\ 006[7 "CH#\ 019[1 "CH#\ 012[7 "CH#\ 013[1 "CH#\ 015[5 "C#\ 024[0 "C#\ 031[5 "C#\ 032[3 "CH#\ 033[9 "C#\ 041[0 "C#\ 058[6 "C#\ 069[0 "C#\ 060[7 "C#\ 197[4 "C#[ Nahocol A0 methyl ether "2b#[ To a soln of 0a "029[0 mg# and MeI "9[06 ml# in dry DMF "0 ml#\ was added Ag1O "64 mg# and the mixt[ stirred at room temp[ overnight[ After the reaction was complete\ H1O and EtOAc were added to the reaction mixt[ The EtOAc layer was washed with H1O and satd[ NaCl soln\ suc! cessively\ and then dried over Na1SO3[ Concn of the EtOAc layer under red[ pres[ gave a yellow oil "096[3 mg#\ which was puri_ed by Si!59 chromatography "14) EtOAc in hexane# to give 2b "33[7 mg# as a colourless oil[ ðaŁ14 D −03[0> "c 9[38#[ C29H33O5\ EIMS "m:z# 499\ 371\ 357\ 085\ 053\ 72[ IR "nmax cm−0# 2349\ 0629\ 0694\ 0599\ 0384\ 0329\ 0269\ 0239\ 0299\ 0169\ 0109\ 0059\ 0099\ 0999\ 819[ UV ðlmax nm "log o#Ł 196 "3[2#\ 116 "3[0#\ 189 "2[4#[ 0H NMR] d 0[94 "2H\ d\ J  5[6 Hz#\ 0[1Ð0[3 "1H\ m#\ 0[31 "2H\ s#\ 0[45 "2H\ s#\ 0[6Ð0[64 "1H\ m#\ 0[79 "2H\ d\ J  0[0 Hz#\ 0[75

0909

N[ TSUCHIYA et al[

"2H\ d\ J  0[1 Hz#\ 0[83 "1H\ t\ J  6[9 Hz#\ 1[97 "1H\ m#\ 1[57 "0H\ sixtet\ J  5[4 Hz#\ 2[47 "0H\ d\ J  04[8 Hz#\ 2[52 "0H\ d\ J  04[8 Hz#\ 2[57 "2H\ s#\ 2[64 "2H\ s#\ 2[68 "0H\ d\ J  3[5 Hz\ D1O!exchangeable#\ 3[75 "0H\ dd\ J  3[5\ 8[7 Hz#\ 3[87 "0H\ br d\ J  8[7 Hz#\ 4[09 "0H\ t\ J  6[9 Hz#\ 4[06 "0H\ d\ J  06[5 Hz#\ 4[08 "0H\ d\ J  00[0 Hz#\ 5[94 "0H\ dd\ J  00[0\ 06[5 Hz#\ 5[54 "0H\ dd\ J  2[0\ 8[8 Hz#\ 5[64 "0H\ d\ J  2[0 Hz#\ 5[87 "0H\ d\ J  8[8 Hz#[ 02C NMR] d 04[6 "CH2#\ 05[1 "CH2#\ 07[5 "CH2#\ 11[2 "CH1#\ 11[4 "CH2#\ 14[2 "CH1#\ 14[8 "CH2#\ 22[5 "CH1#\ 25[5 "CH1#\ 28[6 "CH1#\ 30[2 "CH#\ 31[1 "CH1#\ 40[7 "CH2#\ 44[4 "CH2#\ 63[2 "CH#\ 70[6 "CH#\ 001[3 "CH#\ 003[1 "CH1#\ 005[3 "CH#\ 008[3 "CH#\ 010[2 "CH#\ 013[5 "CH#\ 016[0 "C#\ 023[5 "C#\ 028[7 "C#\ 032[6 "CH#\ 037[1 "C#\ 042[7 "C#\ 061[0 "C#\ 103[5 "C#[ Conversion of 0b to 3a and 3b[ To a soln of 0b "049 mg# in MeOH "1 ml#\ was added 4) NaOH soln[ The mixt[ was kept at room temp[ for 1 hr[ The residue obtained by usual work!up\ was subjected to RP!07 chromatography "59) aq[ ACN# to give 3a "12[8 mg# and 3b "less mobile\ 07[0 mg#[ 3a[ Colourless oil[ ðaŁ14 D −07[8> "c 9[6#[ C17H39O5\ EIMS "m:z# 361\ 343\ 242\ 160\ 132\ 049\ 011\ 72[ IR "nmax cm−0# 2249\ 0609\ 0564\ 0504\ 0384\ 0339\ 0399\ 0264\ 0179\ 0109\ 0989\ 0929\ 0999\ 819[ UV ðlmax nm "log o#Ł 195 "3[1#\ 123 "3[1#\ 182 "2[2#[ 0H NMR] d 0[98 "2H\ d\ J  6[9 Hz#\ 0[9Ð0[0 "1H\ m#\ 0[1Ð0[15 "1H\ m#\ 0[34 "2H\ s#\ 0[41 "2H\ s#\ 0[6Ð1[0 "6H\ m#\ 0[85 "2H\ s#\ 1[10 "2H\ s#\ 2[47 "0H\ d\ J  05[0 Hz#\ 2[51 "0H\ d\ J  05[0 Hz#\ 3[97 "0H\ d\ J  1[4 Hz#\ 4[95 "0H\ t\ J  5[7 Hz# 4[07 "0H\ d\ J  06[5 Hz#\ 4[10 "0H\ d\ J  00[9 Hz#\ 5[59 "0H\ dd\ J  00[9\ 06[5 Hz#\ 5[00 "0H\ br s#\ 5[59 "0H\ dd\ J  1[8\ 7[8 Hz#\ 5[58 "0H\ d\ J  1[8 Hz#\ 5[84 "0H\ d\ J  7[8 Hz#[ 02C NMR] d 04[5 "CH2#\ 06[1 "CH2#\ 10[3 "CH2#\ 11[1 "CH2#\ 11[3 "CH1#\ 14[2 "CH1#\ 17[0 "CH2#\ 18[0 "CH1#\ 25[6 "CH#\ 25[7 "CH1#\ 28[4 "CH1#\ 31[0 "CH1#\ 70[0 "CH#\ 71[5 "C#\ 003[3 "CH#\ 003[5 "CH1#\ 006[7 "CH#\ 008[6 "CH#\ 019[9 "CH#\ 013[0 "CH#\ 015[6 "C#\ 024[9 "C#\ 032[2 "CH#\ 038[6 "C#\ 049[1 "C#\ 048[4 "C#\ 065[1 "C#\ 199[0 "C#[ 3b[ Colourless oil[ ðaŁ14 D ¦11[7> "c 9[36#[ C17H39O5\ EIMS "m:z# 361\ 343\ 242\ 160\ 132\ 049\ 011[ IR "nmax cm−0# 2214\ 0609\ 0564\ 0504\ 0384\ 0339\ 0399\ 0279\ 0179\ 0109\ 0989\ 0929\ 0999\ 819[ UV ðlmax nm "log o#Ł 193 "3[4#\ 122 "3[2#\ 182 "2[4#[ 0H NMR] d 9[54 "2H\ d\ J  5[7 Hz#\ 0[1Ð1[0 "00H\ m#\ 0[31 "2H\ s#\ 0[47 "2H\ s#\ 0[85 "2H\ d\ J  9[8 Hz#\ 1[11 "2H\ d\ J  9[5 Hz#\ 2[48 "1H\ s#\ 3[10 "0H\ d\ J  1[2 Hz#\ 4[01 "0H\ t\ J  5[8 Hz#\ 5[10 "0H\ d\ J  06[5 Hz#\ 4[11 "0H\ d\ J  00[0 Hz#\ 5[95 "0H\ d\ J  00[0\ 06[5 Hz#\ 5[97 "0H\ br s#\ 5[59 "0H\ dd\ J  1[8\ 7[7 Hz#\ 5[57 "0H\ d\ J  1[8 Hz#\ 5[84 "0H\ d\ J  7[7 Hz#[ 02C NMR] d 01[6 "CH2#\ 04[6 "CH2#\ 10[3 "CH2#\ 11[2 "CH2#\ 11[3 "CH1#\ 14[4 "CH1#\ 17[0 "CH2#\ 22[3 "CH1#\ 25[0 "CH#\ 25[6 "CH1#\ 28[5 "CH1#\ 31[1 "CH1#\ 67[6 "CH#\ 71[2 "C#\ 003[3 "CH#\ 003[4 "CH1#\ 006[8 "CH#\ 008[1 "CH#\ 019[9 "CH#\ 013[2 "CH#\ 015[6 "C#\ 024[9 "C#\ 032[2 "CH#\ 036[6 "C#\ 049[1 "C#\ 048[7 "C#\ 064[4 "C#\ 199[7 "C#[

Nahocol C acetonide "4a#[ A mixt[ of 0d "7[2 mg# and p!TsOH "0 mg# in Me1CO dimethyl acetal "0 ml# was kept at room temp[ for 29 min[ After addition of EtOAc and satd NaHCO2 soln\ the reaction mixt[ was stirred at room temp[ for 29 min[ The EtOAc extract\ after usual work!up\ was puri_ed by HPLC "ODS\ 89) aq[ MeOH# to give 4a "6[2 mg# as a colourless oil[ ðaŁ14 D ¦14[0> "c 9[15#[ C21H37O5\ FABMS "m:z# 440 ð"M¦Na#¦Ł[ IR "nmax cm−0# 2591\ 1877\ 1825\ 0625\ 0567\ 0591\ 0386\ 0327\ 0302\ 0279\ 0234\ 0302\ 0057\ 0099\ 0939\ 0992\ 771[ UV ðlmax nm "log o#Ł 193 "3[4#\ 122 "3[2#\ 182 "2[4#[ 0H NMR] d 9[84 "0H\ m#\ 0[99 "2H\ d\ J  5[6 Hz#\ 0[02 "0H\ m#\ 0[15 "0H\ m#\ 0[24 "2H\ s#\ 0[28 "2H\ s#\ 0[3Ð0[5 "1H\ m#\ 0[36 "2H\ s#\ 0[44 "2H\ s#\ 0[6Ð0[7 "1H\ m#\ 0[76 "1H\ m#\ 1[95 "1H\ m#\ 2[4 "0H\ d\ J  04[8 Hz#\ 2[51 "0H\ d\ J  04[8 Hz#\ 2[57 "2H\ s#\ 2[79 "0H\ dd\ J  4[7\ 8[9 Hz#\ 3[44 "0H\ s#\ 3[67 "0H\ dd\ J  4[7\ 09[1 Hz#\ 4[97 "0H\ t\ J  6[9 Hz#\ 4[06 "0H\ d\ J  06[5 Hz#\ 4[08 "0H\ d\ J  00[9 Hz#\ 4[16 "0H\ dd\ J  0[0\ 8[9 Hz#\ 5[94 "0H\ dd\ J  00[9\ 06[5 Hz#\ 5[48 "0H\ dd\ J  2[9\ 7[8 Hz#\ 5[58 "0H\ d\ J  2[9 Hz#\ 5[82 "0H\ d\ J  7[8 Hz#[ 02C NMR] d 04[7 "CH2#\ 05[6 "CH2#\ 06[8 "CH2#\ 11[24 "CH1#\ 11[33 "CH2#\ 14[9 "CH1#\ 14[6 "CH2#\ 15[0 "CH2#\ 17[2 "CH2#\ 21[7 "CH1#\ 22[9 "CH#\ 25[2 "CH1#\ 39[9 "CH1#\ 31[1 "CH1#\ 40[7 "CH2#\ 63[7 "CH#\ 70[6 "C#\ 71[5 "CH#\ 096[3 "C#\ 003[0 "CH#\ 003[2 "CH1#\ 006[6 "CH#\ 019[9 "CH#\ 010[5 "CH#\ 013[9 "CH#\ 016[1 "C#\ 024[3 "C#\ 025[2 "C#\ 032[6 "CH#\ 037[1 "C#\ 038[6 "C#\ 061[1 "C#[ Nahocol D0 acetonide "4b#[ According to the method of the prepn for 4a\ 4b "7[6 mg# was obtained as a colourless oil from 0e "07 mg#[ ðaŁ14 D ¦00[0> "c 9[3#[ C21H35O5\ FABMS "m:z# 438 ð"M¦Na#¦Ł[ IR "nmax cm−0# 2599\ 1877\ 1825\ 0625\ 0566\ 0386\ 0327\ 0302\ 0271\ 0233\ 0177\ 0055\ 0152\ 776[ UV ðlmax nm "log o#Ł 193 "3[4#\ 122 "3[2#\ 182 "2[4#[ 0H NMR] d 0[26 "2H\ s#\ 0[39 "2H\ s#\ 0[42 "2H\ s#\ 0[48 "2H\ s#\ 0[56 "2H\ d\ J  0[0 Hz#\ 0[60 "2H\ s#\ 0[6Ð0[7 "1H\ m#\ 0[84Ð1[04 "1H\ m#\ 2[45 "0H\ d\ J  05[9 Hz#\ 2[51 "0H\ d\ J  05[9 Hz#\ 2[57 "2H\ s#\ 3[42 "0H\ d\ J  6[1 Hz#\ 3[44 "0H\ s#\ 3[83 "0H\ dd\ J  6[1\ 7[2 Hz#\ 4[01 "0H\ d\ J  7[2 Hz#\ 4[02 "0H\ t\ J  6[9 Hz#\ 4[06 "0H\ d\ J  06[4 Hz#\ 4[07 "0H\ d\ J  00[9 Hz#\ 4[33 "0H\ t\ J  6[9 Hz#\ 5[94 "0H\ dd\ J  00[9\ 06[4 Hz#\ 5[47 "0H\ dd\ J  2[9\ 7[7 Hz#\ 5[58 "0H\ d\ J  2[9 Hz#\ 5[82 "0H\ d\ J  7[7 Hz#[ 02C NMR] d 02[7 "CH2#\ 04[8 "CH2#\ 07[2 "CH2#\ 11[3 "CH1#\ 11[4 "CH2#\ 14[9 "CH2#\ 14[8 "CH2#\ 15[1 "CH1#\ 16[1 "CH2#\ 25[2 "CH1#\ 28[2 "CH1#\ 31[0 "CH1#\ 40[8 "CH2#\ 64[0 "CH#\ 70[6 "C#\ 71[8 "CH#\ 096[7 "C#\ 003[0 "CH#\ 003[1 "CH1#\ 006[6 "CH#\ 019[9 "CH#\ 010[3 "CH#\ 013[0 "CH#\ 016[9 "CH#\ 016[1 "C#\ 020[5 "C# 024[1 "C#\ 025[8 "C#\ 032[6 "CH#\ 037[1 "C#\ 038[6 "C#\ 061[2 "C#[ Nahocol D1 acetonide "4c#[ According to the method of the prepn for 4a\ 4c "00[0 mg# was obtained as a colourless oil from 0f "07 mg#[ ðaŁ14 D ¦1[1> "c 9[3#[ C21H35O5\ FABMS "m:z# 438 ð"M¦Na#¦Ł[ IR "nmax cm−0# 2599\ 1877\ 1825\ 0625\ 0570\ 0386\ 0327\ 0302\ 0270\ 0233\ 0177\ 0054\ 0090\ 0928\ 777[ 0H NMR] d

Aryl phenyl esters from Sar`assum autumnale

0[28 "2H\ s#\ 0[33 "2H\ s#\ 0[34 "2H\ s#\ 0[47 "2H\ s#\ 0[53 "2H\ d\ J  0[1 Hz#\ 0[55 "2H\ s#\ 0[64 "2H\ d\ J  0[0 Hz#\ 0[44Ð0[7 "1H\ m#\ 0[84Ð1[1 "1H\ m#\ 2[46 "0H\ d\ J  04[7 Hz#\ 2[50 "0H\ d\ J  04[7 Hz#\ 2[57 "2H\ s#\ 2[86 "0H\ d\ J  7[4 Hz#\ 3[34 "0H\ t\ J  7[4 Hz#\ 3[59 "0H\ s#\ 4[01 "0H\ t\ J  5[3 Hz#\ 4[05 "0H\ d\ J  6[8 Hz#\ 4[07 "0H\ d\ J  06[5 Hz#\ 4[08 "0H\ d\ J  00[9 Hz#\ 4[38 "0H\ t\ J  5[8 Hz#\ 5[94 "0H\ dd\ J  00[9\ 06[5 Hz#\ 5[47 "0H\ dd\ J  2[9\ 7[7 Hz#\ 5[57 "0H\ d\ J  2[9 Hz#\ 5[82 "0H\ d\ J  7[7 Hz#[ 02C NMR] d 00[6 "CH2#\ 04[8 "CH2#\ 07[4 "CH2#\ 11[2 "CH1#\ 11[4 "CH2#\ 15[9 "CH2#\ 15[4 "CH1#\ 16[9 "CH2#\ 16[3 "CH2#\ 25[2 "CH1#\ 28[0 "CH1#\ 31[0 "CH1#\ 40[8 "CH2#\ 65[9 "CH#\ 70[6 "C#\ 75[3 "CH#\ 097[0 "C#\ 003[0 "CH#\ 003[2 "CH1#\ 006[6 "CH#\ 008[5 "CH#\ 010[5 "CH#\ 013[0 "CH#\ 016[1 "C#\ 018[3 "CH#\ 029[1 "C# 024[9 "C#\ 028[2 "C#\ 032[6 "CH#\ 037[0 "C#\ 049[9 "C#\ 061[2 "C#[ Isonahocol D0 acetonide "5a#[ According to the method of the prepn for 4a\ 5a "0[7 mg# was obtained as a colourless oil from 1a "6[3 mg#[ ðaŁ14 D −18[3> "c 9[98#[ C21H35O5\ FABMS "m:z# 438 ð"M¦Na#¦Ł[ IR "nmax cm−0# 2593\ 2253\ 1877\ 1823\ 0622\ 0559\ 0595\ 0370\ 0359\ 0339\ 0271\ 0053\ 0912\ 775[ 0H NMR] d 0[39 "2H\ s#\ 0[41 "2H\ s#\ 0[43 "2H\ s#\ 0[59 "2H\ s#\ 0[56 "2H\ s#\ 0[60 "2H\ s#\ 0[65 "2H\ s#\ 1[99 "1H\ t\ J  6[2 Hz#\ 1[94Ð1[14 "5H\ m#\ 2[23 "1H\ d\ J  6[2 Hz#\ 2[59 "1H\ s#\ 2[63 "2H\ s#\ 3[44 "0H\ d\ J  6[0 Hz#\ 3[73 "0H\ s#\ 3[84 "0H\ dd\ J  6[0\ 7[7 Hz#\ 4[01 "0H\ d\ J  7[7 Hz#\ 4[04 "0H\ t\ J  5[5 Hz#\ 4[23 "0H\ t\ J  5[4 Hz#\ 4[34 "0H\ t\ J  5[8 Hz#\ 5[36 "0H\ d\ J  2[9 Hz#\ 5[45 "0H\ d\ J  2[9 Hz#\ 5[63 "0H\ s#[ 02C NMR] d 02[8 "CH2#\ 04[8 "CH2#\ 07[1 "CH2#\ 12[4 "CH2#\ 13[8 "CH2#\ 14[7 "t#\ 14[8 "CH2#\ 15[3 "CH2#\ 16[1 "CH2#\ 18[9 "CH1#\ 21[9 "CH1#\ 26[4 "CH1#\ 28[1 "CH1#\ 41[5 "CH2#\ 64[9 "CH#\ 71[1 "CH#\ 096[7 "C#\ 004[9 "CH#\ 004[8 "CH#\ 010[1 "CH#\ 010[5 "C#\ 011[4 "CH#\ 013[1 "CH#\ 016[9 "CH#\ 029[8 "C# 020[3 "C#\ 024[0 "C#\ 026[0 "C#\ 026[4 "C#\ 035[7 "C#\ 038[1 "C#\ 063[9 "C#[ Isonahocol D1 acetonide "5b#[ According to the method of the prepn for 4a\ 5b "4[3 mg# was obtained as a colourless oil from 1b "00[7 mg#[ ðaŁ14 D −05[6> "c 9[2#[ C27H39O5\ FABMS "m:z# 438 ð"M¦Na#¦Ł[ IR "nmax cm−0# 2593\ 2253\ 1877\ 1824\ 0622\ 0698\ 0548\ 0596\ 0370\ 0348\ 0339\ 0271\ 0052\ 0912\ 775[ 0H NMR] d 0[39 "2H\ s#\ 0[41 "2H\ s#\ 0[42 "2H\ s#\ 0[48 "2H\ s#\ 0[56 "2H\ d\ J  0[9 Hz#\ 0[60 "2H\ s#\ 0[65 "2H\ s#\ 1[99 "1H\ t\ J  6[2 Hz#\ 0[88 "1H\ m#\ 1[94Ð 1[19 "5H\ m#\ 2[23 "1H\ d\ J  6[1 Hz#\ 2[50 "1H\ s#\ 2[63 "2H\ s#\ 3[41 "0H\ d\ J  6[9 Hz#\ 3[47 "0H\ s#\ 3[83 "0H\ dd\ J  6[9\ 7[7 Hz#\ 4[0Ð4[04 "1H\ m#\ 4[29 "0H\ t\ J  5[1 Hz#\ 4[32 "0H\ t\ J  5[1 Hz#\ 5[37 "0H\

0900

d\ J  2[9 Hz#\ 5[45 "0H\ d\ J  2[9 Hz#\ 5[53 "0H\ s#[ C NMR] d 02[7 "CH2#\ 05[9 "CH2#\ 07[2 "CH2#\ 12[4 "CH2#\ 14[9 "CH2#\ 14[8 "CH2#\ 15[0 "CH1#\ 15[3 "CH1#\ 16[1 "CH2#\ 18[0 "CH1#\ 21[9 "CH1#\ 26[3 "CH1#\ 28[2 "CH1#\ 41[5 "CH2#\ 64[0 "CH#\ 72[9 "CH#\ 096[7 "C#\ 004[0 "CH#\ 004[8 "CH#\ 010[2 "CH#\ 010[6 "C#\ 010[7 "CH#\ 013[1 "CH#\ 016[1 "C#\ 029[6 "C#\ 020[3 "C# 024[9 "C#\ 026[9 "C#\ 026[4 "C#\ 035[8 "C#\ 038[0 "C#\ 062[8 "C#[

02

Acknowled`ements*The authors are indebted to Prof[ M[ Kajimura of Oki Marine Biological Exper! imental Station\ Shimane University\ and Prof[ Y[ Yokohama\ Director of Shimoda Marine Research Center\ University of Tsukuba\ for the collection and identi_cation of plant material[ REFERENCES

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