The question of the tautomerism of isatin

Abstract

1. By the action of bromomethyl and chloromethyl ethers of methyl, ethyl, and propyl alcohols on the sodium and silver derivatives of isatin, the corresponding isatin ethers have been prepared; isatin methoxymethyl ether of m.p. 90–91*, isatin ethoxymethyl ether m.p. 85–85*, and isatin propoxymethyl ether of m.p. 79–80*. 2. All the derivatives obtained were readily hydrolyzed. 3. The hydrolysis products of the methoxy-, ethoxy-, and propoxy-methyl ethers of isatin were istain (obtained in almost quantitative yield), formaldehyde, and the corresponding alcohols. 4. By the action on the sodium and silver derivatives of isatin of (α-bromo-α,α-diphenyl-p-tolyl)-triphenylmethane, of benzyl bromide and chloride, and of aα-bromo-p-xylene there were obtained diphenyl-(α,α,α-triphenyl-p-tolyl)-methylisatin of m.p. 250–252*, benzylisatin of m.p. 131*, and (p-tolylmethyl)-isatin of m.p. 141–142*. 5. Attempts to hydrolyze the substances of m.p. 131*, 141–142*, and 250–252* did not give satisfactory results; the substances were recovered unchanged. The question of their structures remains an open one. 6. When the methoxymethyl and ethoxymethyl derivatives of isatin are heated with methyl iodide or with benzyl bromide, high-melting produces are obtained. 7. Benzylisatin remains unchanged in presence of methyl iodide or of benzyl bromide.