Oxindole, 3-ethyl-I-methyl

Two representatives of this class of compounds, one with a free NH— benzopyrano[2,3-b]indole(VIII)—and the other, an V-methyl derivative (IX) were prepared by the condensation of oxindoles with ethyl salicylate in the presence of sodium hydride, followed by ring closure with hydrochloric acid (Scheme 1) [6]. The products were identified by elemental analyses as well as by their spectra (u.v., i.r., n.m.r. and mass). Methylation of (VIII) also gave (IX) in 77 per cent yield. 

Ozone bubbled briefly into an ice-cooled soln. of 3-cyano-4-ethyl-4-methyl-l-tosyl-l,4-dihydroquinoline in methylene diloride, and the resulting ozonide refluxed briefly with methanol containing 5%-HCl 3-ethyl-3-methyl-l-tosyl-oxindole. Y ca. 100%. F. e. s. M. Natsume and I. Utsunomiya, Chem. Pharm. Bull. 20, 1595 (1972). 

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