Abstract
The cyclic tautomer (5) of Nb-methyl-3-indoleacetamide (4) has been prepared by dissolving 4 in phosphoric acid. The bromination of 5 with 1 or 2 mol of N-bromosuccinimide (NBS) or 2, 4, 4, 6-tetrabromo-2, 5-cyclohexadienone (TABCO) gave the 5-bromo- (8) and the 5, 7-dibromo (9) derivatives. On the other hand, the 5-bromo derivative (11) was the major product of the bromination of the N-acetyl cyclic tautomer (6) even with 2 mol of NBS. The 5-nitro derivative (17) was obtained in excellent yield by the nitration of 6 with ammonium nitrate in trifluoroacetic anhydride (TFAA). Reduction of 17 followed by bromination gave the 4, 6-dibromo derivative (19), which gave the tribromide (20) in the Sandmeyer reaction. The 4, 5, 6-tribromo-3-indoleacetamide (7), which is the indole moiety of a marine indole alkaloid, chartelline A, was obtained by the ring opening of 20. Furthermore, the oxidation of 5 with lead tetraacetate followed by acetylation gave the 5-acetoxy derivative (22). The selective hydrolysis and bromination of 22 gave the 4, 6-dibromo-5-hydroxy derivative (24).
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
