A-Alkyltryptamines

Moderately Potent Antidepressant Agents. Replacement of the phenyl by an indole ring in amphetamine resulted in the development of a group of oj-alkyltryptamines ... 

Dihydro-l-methyl-y -carboline refluxed 1 hr. with hydrazine hydrate and KOH in diethylene glycol under. Ng 2-ethyltryptamine. Y 92%. — This is a simple synthesis of the little known 2-alkyltryptamines. F. e. s. I. Fleming and J. Harley-Mason, Soc. (C) 1966, 425. 

A protonated Schiff s base (11) is the presumed intermediate in the Mannich reaction. From the condensation of tryptamine with benzal-dehyde a Schiff s base (10 R = CgHg) has indeed been isolated, which on treatment with acid cyclizes to l-phenyl-l,2,3,4-tetrahydro-j8-carboline(14 R = CeHg). Condensation ofa tryptamine derivative with an aldehyde in the absence of acid leads to the corresponding Schiff s base (10), the structure of which has been proved by reduction to an Ajg-alkyltryptamine derivative (13) with sodium boro-hydride. Reconversion of a l,2,3,4-tetrahydro-j8-carboline (14 R = CH2C6H3-3,4- 0H)2) into the corresponding protonated SchifiF s base of tryptamine (11) has been postulated as a step in the rearrangement in strong acid of this 1,2,3,4-tetrahydro-jS-carboline derivative into an indolenine (see Section IV, B, 3). One instance of a Mannich-type condensation of an aldehyde with a modified tryptamine derivative into the jS-position, rather than into the a-position, of the indole... 

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