The Chemistry of Indoles. XVI. A Convenient Synthesis of Substituted Indoles carrying a Hydroxy Group, a Halogeno Group, or a Carbon Side Chain at the 4-Position via 4-Indolediazonium Salts and a Total Synthesis of (±)-6, 7-Secoagroclavine

Abstract

Various 4-indolediazonium salts were prepared for the first time by the diazotization of 4-aminoindole derivatives. They underwent various reactions parallel to those of general arene diazonium salts, and were found to be suitable intermediates for the preparation of substituted indoles carrying a hydroxy, halogeno, or cyano group at the 4-position. Attempts to introduce various carbon side chains into the 4-iodoindole derivatives gave satisfactory results and a key intermediate, 4-(3-hydroxy) 3-methyl-1-buten-1-yl) indole, for the synthesis of (±)-6, 7-secoagroclavine was also prepared.