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Chapter – 4 Studies on different types of reactions…..
nitrophenylaceticacid with tin and hydrochloric acid. Current practice in
oxindole nomenclature is to number the positions as shown in the Fig. 4.1.
Oxindole is frequently called indolinone which is now well accepted
25, 26
everywhere.
4.2.2 SYNTHESIS OF OXINDOLES
Synthesis of oxindole and its derivatives are also a part of known
chemistry where many methods are reported.
Baeyer and Knop 27 found that when isatin isreduced with sodium
amalgam in alkaline medium 3-hydroxy oxindole (dioxindal) is obtained.
Further reduction of dioxindole with tin and mineral acids or by sodium
amalgam in acid medium gave oxindole.
One convenient method for preparing oxindole is that of Marschalle. 28,
29
In this procedure isatin is reduced to dioxindole through the agency of
sodium hydrosulphite. Dioxindale is then reduced to oxindole by the action of
sodium amalgam in a solution saturated with carbon dioxide.
Isatin was also reduced to oxindole through the agency of hydrazide by
Curtius and Thun. 30
The first synthesis of oxindole (other than the reduction of isatin) and
the one who established its constitution with certainly was by Baeyer 31
through the reduction of 2-nitrophenylaceticacid with tin and hydrochloric acid.
Reduction of 2-nitro phenylacetic acid with Zn and hydrochloric acid
gives both oxindole and 1-hydroxyoxindole (1, 2-dioxindole) 32-34
Baeyer and Comstok 35 prepared oxindole from the barium salt of 2aminophenyl
acetic acid by acidifying and then heating.
Substituted oxindoles have been prepared by the reduction of
substituted derivatives of 2-nitrophenylacetic acid by Wispec, 36 Smith and
Macmullen 37 and many other workers.
Department of Chemistry, Saurashtra University, Rajkot – 360 005 191