Synthesis of Bromoindole Alkaloids from Laurencia brongniartii

• Published in: Journal of natural products (Washington, D.C.) Vol. 69; no. 11; pp. 1596 - 1600
• Main Authors: Suárez-Castillo, Oscar R, Beiza-Granados, Lidia, Meléndez-Rodríguez, Myriam, Álvarez-Hernández, Alejandro, Morales-Ríos, Martha S, Joseph-Nathan, Pedro
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 01.11.2006; Amer Chemical Soc; American Society of Pharmacognosy
• Subjects: Chemistry; Chemistry, Medicinal; Crystallography, X-Ray; Exact sciences and technology; Heterocyclic compounds; Heterocyclic compounds with only one n hetero atom and condensed derivatives; Hydrocarbons, Brominated - chemical synthesis; Hydrocarbons, Brominated - chemistry; Indole Alkaloids - chemical synthesis; Indole Alkaloids - chemistry; Laurencia - chemistry; Life Sciences & Biomedicine; Molecular Conformation; Molecular Structure; Organic chemistry; Pharmacology & Pharmacy; Plant Sciences; Preparations and properties; Science & Technology; OXIDATION; METHOXYL GROUP; SUBSTITUTION; NMR; BROMINATION; INDOLE-DERIVATIVES; Rhodophyta; Regioselectivity; Bromination; Nitrogen heterocycle; Algae; Total synthesis; Medicinal plant; Alkaloid; Bicyclic compound; Bromine Organic compounds; Aromatic compound; Chemical synthesis; Thallophyta
• ISSN: 0163-3864; 1520-6025
• DOI: 10.1021/np060406a

A regioselective synthesis of N-carbomethoxy-2,3,5-tribromoindole (6) via a sequential one-pot bromination−aromatization−bromination of N-carbomethoxyindoline (2) is described. The process for the transformation of 2 into 6 permitted the isolation of stable reaction intermediates N-carbomethoxy-5-bromoindoline (3), N-carbomethoxy-5-bromoindole (4), and N-carbomethoxy-3,5-dibromoindole (5). Compound 6 was used to complete the total synthesis of the natural products 1b and 1c. In addition, bromination of N-carbomethoxyindole (11) afforded N-carbomethoxy-2,3,6-tribromoindole (13), from which the natural product 1a was synthesized.