Novel method for the synthesis of substituted tetrahydrocarbazoles using aqueous sulphuric acid

An efficient and high yielding process has been developed for the synthesis of 6-substituted 3-hydroxy tetrahydrocarbazoles by reacting in situ generated cyclohexanones from the corresponding protected ketals with substituted hydrazine hydrochlorides in the presence of dil. Sulfuric acid. A small library of fourteen compounds has been made with 92-97% yields to check the generality of the reaction.