Original scientific paper

Indole Compounds. IV. Suhstituent Effects on the Cyclization of Phenylhydrazines with Acetals into Bz,3-Disubstituted Indoles

D. Desaty ; Tracer Laboratory, Institute »Ruder Boskovic «, Zagreb, Croatia, Yugoslavia
D. Keglević ; Tracer Laboratory, Institute »Ruder Boskovic «, Zagreb, Croatia, Yugoslavia

Abstract

The condensation of a number of phenylhydrazine hydrochlorides
with various ace tals in 25°,'o acetic acid at 50-800 was investigated
a:nd several new indoles prepared. It was established that
under these conditions the determinant factor for a successful
indolization is the presence of a nucleophi li c substitu ent in paraor
less favourably in ortho- position on the aromatic nucleus of
the phenylhydrazine moiety. The nature of the aliphatic acetal
moiety (unsubstituted, 4-amino , 3- or 4-acylamino, 3-cyano) does
not effect substantially the relative ease of indolization. When
free aldehydes were u sed ins·tead of the corresponding aliphatic
unsubstituted qiethyl acetals, the yield s on 5- or 7-substituted-3-
-alkyHndoles dropped considerably. The smooth syntheses of
5-benzyloxy-, 5-methoxy-, and 5-ethoxy-indole-3-acetonitriles suggest
thi·s way as a prepara tive method for these compounds.

Keywords

Hrčak ID:

208229

URI

https://hrcak.srce.hr/208229

Publication date:

15.5.1965.

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