Microwave-assisted traceless synthesis of hydantion-fused beta-carboline scaffold

Abstract

Multistep microwave-assisted reactions toward the synthesis of hydantoin-fused tricyclic tetrahydro-beta-carbolines on the soluble polymer support have been developed. Polymer-bound tryptophan with various aldehydes has been subjected to Pictet-Spengler reaction to obtain tricyclic beta-carboline conjugates. The terminal hydantoinyl moiety is constructed across polymer-bound beta-carbolines by the reaction with various isocyanates under microwave irradiation to form urea intermediate. Simultaneous intramolecular cyclization of urea followed by cleavage of the polymer support leads to a traceless synthesis of tetracyclic scaffolds in high yield and high purity. (c) 2007 Elsevier Ltd. All rights reserved.