Intramolecular Mannich Reaction of 2-Oxotryptamine and Homologues with Oxo Reagents Yielding Spiro Compounds. Part II

Divergent reactions of oxindoles with amino alcohols via the borrowing hydrogen process: oxindole ring opening vs. C3 alkylation

Oxindoles react with N-acetyl amino alcohols to form tryptamine-derived oxindoles, whereas analogous reactions with N-alkyl amino alcohols lead to lactam formation via a relatively mild borrowing hydrogen process.

Structure-activity study of brassinin derivatives as indoleamine 2,3-dioxygenase inhibitors

A screen of indole-based structures revealed the natural product brassinin to be a moderate inhibitor of indoleamine 2,3-dioxygenase (IDO), a new cancer immunosuppression target. A structure-activity study was undertaken to determine which elements of the brassinin structure could be modified to enhance potency. Three important discoveries have been made, which will impact future IDO inhibitor development: (i) The dithiocarbamate portion of the brassinin lead is a crucial moiety, which may be binding to the heme iron of IDO; (ii) an indole ring is not necessary for IDO inhibition; and (iii) substitution of the S-methyl group of brassinin with large aromatic groups provides inhibitors that are three times more potent in vitro than the most commonly used IDO inhibitor, 1-methyl-tryptophan.