Lignans of western red cedar (Thujaplicata Donn). IX. Plicatinaphthalene

Abstract

The last of nine lignans detectable by thin-layer chromatography in the hot-water soluble extractives of western red cedar (Thujaplicata Donn) heartwood has been determined as 6-hydroxy-2(hydroxy-methyl)-7-methoxy-4-(3′,4′-dihydroxy-5′-methoxyphenyl)-3-naphthoic acid lactone (plicatinaphthalene 2) by spectrometric methods, by degradation studies of derivatives, and by preparation of its trimethyl ether derivative 3 from dehydroanhydropicropodophyllin by opening of the methylenedioxy group with boron trichloride.

Arylnaphthalene lignans. Synthesis of justicidin E, taiwanin C, dehydrodimethylconidendrin, and dehydrodimethylretrodendrin

“…Several crystalline extractives have been iso-lated15 from the heartwood of Taiwania cryptomerioides Hayata and for one of these, taiwanin C, the structure 6,7-methylenedioxy-l-(3',4'-methylenedioxyphenyl)-3hydroxymethylnaphthalene-2-carboxylic acid lactone (VI) has been proposed. 16 The isomeric structure VII has been proposed for a lactone, justicidin E, isolated as a piscicidal constituent from Justicia procumbens, and the conversion of ( -)-parabenzlactone (VIII) to justicidin E is indicated in the same communication.17 We have now prepared taiwanin C and justicidin E by the same simple pathway used for the tetramethoxy lactone I and II and with constants in excellent agreement with those reported for the natural products. 2,3 -Bishydroxymethyl -6,7 -methylenedioxy -1 -(3',4'methylenedioxyphenyl) naphthalene (IX), readily obtained from piperonylpropiolic acid by the action of acetic anhydride followed by reduction with lithium aluminium hydride and aluminium chloride in tetrahydrofuran,18 was oxidized by silver carbonate-Celite to give a lactone mixture from which the major component, justicidin E (VII), was obtained by direct In the structure elucidation of naturally occurring lignari arylnaphthalene lactones, two diagnostic problems have in the past led to erroneous structure assignments.…”

Novel Selective PDE IV Inhibitors as Antiasthmatic Agents. Synthesis and Biological Activities of a Series of 1-Aryl-2,3-bis(hydroxymethyl)naphthalene Lignans

“…A drop in the activity was also observed when the 7-methoxy group was replaced by a hydrogen atom (7c). Transformation of the 2,3-bis(hydroxymethyl) groups into a lactone function (24a) 14 retained the activity. Removal of the 3,4,5-trimethoxyphenyl group (7e) or introduction of a methylene group between the naphthalene ring and 1-phenyl ring (7d) resulted in a substantial loss in activity.…”

Lignans of western red cedar (Thujaplicata Donn). X. γ-Thujaplicatene

“…Previous work has elucidated the structural relationship of nine lignans present in the heartwood of western red cedar (Thuja plicata Donn), two of which were 4-aryltetrahydronaphthalenes, five were substituted dibenzyl butyrolactones, the eighth was a 4-aryl-u-naphthol lactone, and the ninth was an aromatized naphthalene (1).…”

“…The U.V. spectrum of y-thujaplicatene, which showed peaks at 338 and 288 mp, was not indicative of plicatinaphthalene (1) which has peaks at 356, 3 15, and 259 mp, or of the apopicropodophyllin series whose peaks are 310, 290, and 350 mp for the u, p and y positions of the double bond respectively (3). Attempts to shift the conjugated double bond of y-thujaplicatene to the P position by use of piperidine acetic acid (3) were unsuccessful, indicating that the position of the bond remained unchanged.…”