Utilization of 1H-Indole-3-carboxaldehyde as a Precursor for the Synthesis of Bioactive Indole Alkaloids

Abstract Indole alkaloids constitute a large class of natural products and their diverse and complex structures have been attributed to potent biological activities such as anticancer, anti-inflammatory, antimicrobial, antimalarial, antiplasmodial and protein kinase inhibition. The isolation of bioactive compounds from natural sources is difficult, costly and an extremely time-consuming process, therefore synthetic pathways are more convenient than natural separation to deliver such compounds in considerable amounts. In this respect, this review provides comprehensive information on the structures and the synthesis of bioactive indole alkaloids utilizing 1 H -indole-3-carboxaldehyde and its derivatives as starting compounds. 1 Overview 2 Phytoalexins 2.1 Brassinin, Cyclobrassinin and Brassitin 2.2 1-Methoxybrassinin, 1-Methoxyspirobrassinol and 1-Methoxyspirobrassinin 2.3 4-Methoxybrassinin and 4-Methoxycyclobrassinin 2.4 Cyclobrassinone 2.5 Brassilexin 2.6 ( S )-(–)-Spirobrassinin 2.7 Camalexin 3 Bis(indole) Alkaloids: Rhopaladines A–D 4 Coscinamides A and B 5 α-Cyclopiazonic Acid 6 Dipodazine 7 Isocryptolepine 8 Apparicine 9 Carbazole Alkaloids: Mukonine and Clausine E 10 Indolmycin 11 Conclusion