3.4.5- Trimethoxycinnamate

The 3,4,5-trimethoxycinnamic ester of methyl reserpate is also present in Rauwolfia plants and obtainable in purified form therefrom by extraction as described in U.S, Patents 2,974,144 and 2,876,228. 

Trimethoxycinnamic acid Methyl reserpate Thionyl chloride Rauwolfia plants... 

Settimj et al.6 described a gas chromatographic method for the estimation of reserpine and rescinnamine involving alkaline hydrolysis of the alkaloids and subsequent esterification of the acids formed by means of diazomethane. Reserpine gave quantitatively 3,4,5-trimethoxyben-zoic acid methylester, whereas the trars-3,4,5-trimethoxycinnamic acid methylester, which should be expected for rescinnamine, was partly isomerized to the cis-trimethoxycinnamic acid methylester or formed an adduct with a molecule of methanol, yielding 3-methoxy-3-(3,4,5-tr1-methoxyphenyl) propionic acid methylester. 

Another new alkaloid in this series is tropine 3,4,5-trimethoxycinnamate, which occurs in the stem bark of Erythroxylwn ellipticum R. Br. (fam. Erythroxylaceae), a large tree indigenous to Queensland. 

Phenylalanine and p-coumaric acid, but not 3,4-dihydrox-ycinnamic (caffeic) acid or acetate, were incorporated into podophyllotoxin (51). In Podophyllum hexandrwn (Berberi-daceae), both cinnamic and ferulic acids are incorporated into both halves of the molecule. The carbon of the 0-methyl group of ferulic acid is distributed into both rings A and C. Sinapic and 3,4,5-trimethoxycinnamic acids are not incorporated. This suggests that other oxidation and methylation occurs after the initial dimerization reaction (Jackson and Dewick, 1984 Pelter, 1986 Poulton, 1981). 

Seven chlorogenic and hydroxycinnamic acids (caffeic, p- and o-coumeric, ferulic, 4-methoxy-, 3,4-dimethoxy-, 3,4,5-trimethoxycinnamic) were extracted from green coffee and baseline resolved on a Cjg colunm (A = 320 nm) using a complex 47-min 15/85 - 80/20 methanol/water (1% acetic acid) gradient [374]. Peak shapes were excellent. Linear ranges of 4—400 pg/mL with detection limits of 0.1 pg/mL were reported. 

Fig. 6.15 Specific inhibition by trimethoprim and some structurally related compounds of the reaction of IgE antibodies from a trimethoprim-allergic patient with the drug. The IgE antibodies showed specificity for the 3,4-dimethoxybenzyl group of trimethoprim. Key to symbols open circle) trimethoprim (filled circle) 6-hydroxytrimethoprim (open square) 6-chlorotrimethoprim (filled square) diaveridine (filled triangle) 3,4-dimethoxyphenylethylamine (vertical open diamond) 3-(3, 4, 5 -trimethoxyphenyl)-propionic acid (filled diamond) 3,4-dimethoxybenzoic acid (inverted triangle) 4-methoxyphenylethylamine (horizontal open diamond) 3,4,5-trimethoxycinnamic acid. See also Table 6.3 and Fig. 6.16 (reproduced with permission from Smal MA et al. Allergy 1988 43 184)...

Along with 3a-tropine derivatives, characteristic for the plants of the family Erythroxylaceae are the esters of 3jS-tropine (pseudotropine) and ecgonine with benzoic, phenylacetic, 3,4,5-trimethoxybenzoic, 3,4,5-trimethoxycinnamic acids, etc. Dimeric esters of methylecgonine (tmxillines) and tropine (mooniines) have been also reported [15]. 

Meyer T, Scheline RR. 3,4,5-trimethoxycinnamic acid and related compounds. I. Metabolism in by the rat intestinal microflora. Xenobiotica 1972 2 383-390. 

Johns S R, Lamberton J A, Sioumis A A 1977 Tropine 3,4,5-trimethoxycinnamate, a new alkaloid from Erythroxylum ellipticum (Erythroxylaceae). Aust J Chem 23 421-422... 

---