A new gas chromatographic method for the estimation of reserpine and rescinnamine

Under the conditions described for alkaline hydrolysis of reserpine and rescinnamine in absolute and aqueous methanol, and after esterification (with diazomethane) of the resulting acid fraction, methyl 3,4,5-trimethoxybenzoate was quantitatively recovered, whereas methyl trans-3,4,5-trimethoxycinnamate, in normal lighting conditions, was either partly isomerized to methyl cis-trimethoxycinnamate or formed an adduct with a molecule of methanol, yielding methyl 3-methoxy-3-(3,4,5-trimethoxyphenyl)propionate. The structures of the products were established by synthesis, nuclear magnetic resonance studies and mass spectrometry. This investigation of the hydrolytic conditions allowed a reliable and rapid gas chromatographic determination of reserpine and/or rescinnamine in amounts down to 500 and 2000 mug, respectively, to be devised.