Methoxylation of Bromo-1, 2, 3, 4-tetrahydrocarbazoles. Oxidation and Subsequent Rearrangement of 1, 2, 3, 4-Tetrahydrocarbazoles to Spiro-(cyclopentane-1, 2'-indolin)-3'-ones

Abstract

5-Bromo- and 7-bromo-1, 2, 3, 4-tetrahydrocarbazoles (2 and 4) were converted to 4'-methoxy- and 6'-methoxy-spiro (cyclopentane-1, 2'-indolin)-3'-ones (14 and 16) by treatment with excess sodium methoxide in methanol/DMF in the presence of cuprous iodide in 10.3% and 53.7% yields, respectively. On the other hand, N-substituted bromocarbazoles were converted to the corresponding methoxycarbazoles in good yields under the same reaction conditions.