10.1021/jo00149a009
The research focuses on the synthesis and photooxidation of condensation products of tryptamine and catechol derivatives, aiming to approach the synthesis of a probable precursor of the Gelsemium alkaloid koumine. Key chemicals involved include tryptamine, 3,4-dihydroxyphenylpyruvic acid, isopropyl chloroformate, and lithium aluminum hydride. The study successfully synthesized compounds such as 1,3,5,6,14,21-hexahydro-17,18-dihydroxybenz-[g]indolo[2,3-a]quinolizine (2) and 3-ethoxy-3,4-seco-N-methyl-1,3,5,6,14,21-hexahydro-17,18-dihydroxybenz-[g]indolo[2,3-a]quinolizine (5), and achieved the cleavage of their catechol rings through photosensitized oxidation to obtain muconic acid derivatives 7 and 8. These compounds and their transformations played crucial roles in exploring the potential synthesis pathway of koumine.