Gannon, Walter F. published the artcileFischer indole cyclization of several ortho-substituted phenylhydrazones, Related Products of indole-building-block, the publication is Journal of Organic Chemistry (1969), 34(10), 3002-6, database is CAplus.
Fischer indole cyclization of Et pyruvate o-methoxyphenylhydrazone in ethanolic HCl gave 2-carbethoxy-6-chloroindole (I) as the main product. Minor products included 2-carbethoxy-3-chloroindole, the expected 2-carbethoxy-7-methoxyindole and several indolic dimers. Similarly, Et pyruvate o-benzyloxyphenylhydrazone gave I. Cyclization of cyclohexanone o-methoxyphenylhydrazone in dilute H2SO4 yielded 8-methoxy-1,2,3,-4-tetrahydrocarbazole (II) as the major product. The only isolated by-product, previously reported to be 12-methoxy-1,2,3,4-tetrahydroisocarbazole, had a dimeric structure. When the reaction was run in ethanolic HCl, the dimer hydrochloride became the main product and II is formed in lower yield. The structure of the dimers and the reaction mechanism are discussed.
Journal of Organic Chemistry published new progress about 20538-12-9. 20538-12-9 belongs to indole-building-block, auxiliary class Indole,Ester,Ether, name is Ethyl 7-methoxy-1H-indole-2-carboxylate, and the molecular formula is C12H13NO3, Related Products of indole-building-block.
Referemce:
https://www.nature.com/articles/s41429-020-0333-2,
Preparation of Indole Containing Building Blocks for the Regiospecific Construction of Indole Appended Pyrazoles and Pyrroles