Page 92 - phytochemistry general program

N R1 R2
R1 H

NH Reserpine OCH3 Trimethoxybenzoyl
H OCH3 Trimethoxycinnamyl
H OR2 Rescinamine H Trimethoxybenzoyl
Deserpedine

H3COOC OCH3

Reserpine

Properties

Reserpine occurs as fine, white or pale buff or slightly yellow colored crystals
or crystalline powder, m.p.270 ˚C, with decomposition. It is laevorotatory.

Reserpine and related alkaloids are weakly basic ester, tertiary alkaloids and

possess a carboxylic ring "E".

Hydrolysis

On hydrolysis: reserpine yields reserpic acid, trimethoxybenzoic acid and
methanol while recinnamine gives reserpic acid, trimethoxycinnamic acid and
methanol.

Deserpedine is the demethoxylated derivative of reserpine. It lacks the
methoxyl group on ring "A". On hydrolysis it yields deserpic acid,
trimethoxybenzoic and methanol.

Estimation of reserpine

Reserpine is a weakly basic alkaloid that could not be determined by the
usual titrimetric methods. Several other techniques have been deviced for its
estimation including:

Non-aqueous titration. .1
Fluorimetric estimation. .2
Spectrophotometric determination. .3
.4
Biological assay.
Tests for identification

Vanillin /HCl reagent (1%): gives a violet color with reserpine. .1

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