Synthesis and structure elucidation of new 3,5-dihydro-4H-pyrimido[5,4-b]indol-4-one derivatives

Abstract

An efficient approach for the synthesis of 3,5-dihydro-4H-pyrimido[5,4-b]indol-4-one derivatives has been developed. The key compound isothiocyanate was prepared through a simple and ecological method using di-2-pyridyl thionocarbonate (DPT) in substitution of the thiophosgene, a potential air pollutant. The cyclization reaction of thiosemicarbazide derivates was developed through the methods reported by Wanhoff. 3,5-Dihydro-4H-pyrimido[5,4-b]indol-4-one derivatives were synthesized using powdery copper/copper(I) iodide as catalyst, their structural elucidation was confirmed by 1HNMR and mass spectrum. This methodology presents a new alternative synthesis of indole derivatives that are different from existing routes which are limited in structural diversity.

Keywords

• Indole
• Isothiocyanate
• Di-2-pyridyl thionocarbonate
• Cyclohexyl