5-Methoxytryptamine → Melatonin

Participants

Reaction Steps

To a suspension, cooled in ice, of 5 g (26.3 moles) of 5-methoxytryptamine (in a raw condition) in 100 ml methylene chloride there is slowly added, under stirring, a cold solution of 5 ml (52.6 moles) of acetic anhydride in 50 ml of methylene chloride. Stirring and cooling are continued for 1 hour (the reaction progression can be controlled by TLC), so as to obtain a full solution; then the solution is washed by Na2CO3 2N×2, under strong stirring, and then by water. The organic phase, dried on anhydrous Na2SO4 and evaporated, provides 6 g of raw melatonine, which is purified by chromatography on column (4 cm; diameter/length ratio 1:5) of Merck silica gel (70-230 mesh) (120 g); the solution is eluted by methylene chloride in order to remove the scarcely polar products thereby providing pure melatonine by eluting with methylene chloride-acetone (8:2). There are obtained 4 g of product (purifying yield 65%) which are crystalized from acetone-water. Melting point 116°-7° C.

Provenance & Evidence