Tryptamine Prodrugs

A compound of Formula (I) (II), (III) or (IV) or a pharmaceutically acceptable salt or zwitterion thereof:

• wherein:
• (1) R1, R2, and R6 are each independently selected from hydrogen, linear or branched alkyl, or arylalkyl;
• (2) R4 is
• a. —X—CO2H, where X is a linear, cyclic or branched, saturated or unsaturated carbon chain, optionally substituted with —OH or —CO2H;
• or an aromatic ring, optionally substituted with alkyl or CO2H;
• or
• b.
• wherein R9 is X—CO2H, where X is as defined in (2)(a) above and R10 is hydrogen, linear or branched alkyl or arylalkyl, optionally substituted by —OH or —CO2H;
• (3) R5 is hydrogen, linear or branched alkyl, arylalkyl, or O—R5′, where R5′ is hydrogen, linear or branched alkyl;
• and
• (4) R7 and R8:
• a. are each independently selected from hydrogen, linear or branched alkyl, or arylalkyl, or
• b. together form a non-aromatic N-containing heterocycle, optionally substituted with alkyl.