Molecular Rearrangements. VIII. The Equilibration of 3,3-Dimethyl-2-phenyl- and 2,3-Dimethyl-3-phenyl-3H-indoles¹

Abstract

The reaction of isobutyrophenone phenylhydrazone or 3-phenyl-2-butanone phenylhydrazone with polyphosphoric acid gave an equilibrium mixture of 3,3-dimethyl-2-phenyl-3//-indole and 2,3-dimethyl-3-phenyl-3//-indole contrary to previous reports. The preparation of the 3//-indoles from the phenylhvdrazones can be accomplished without equilibration in acetic acid. Some features of the equilibration have been investigated. The spectroscopic properties of the 3//-indoles are re-

Reactions of some heterocyclic quaternary salts with trifluoroacetic anhydride

“…1.2 Hz); the ''F spectrum contained a sharp quartet at tjF -16.3 (J 10 Hz) (pyrazole CF3) and a signal at 6 -13.0 (br q, J 10 Hz, broadened by coupling with NMe). We suggest that, in TFA, compound (18) forms the cation (19). presumably by reduction of the cation (19).…”

“…The 'H n.m.r. spectrum of compound (18) in TFA contained signals at T 2.0-2.45, 5.32 (NMe), 7.8 (CMe), and 8.4 (CMe). The downfield shift of the NMe signal (1.63 p.p.m.)…”

“…(CHCF3). Treatment of compound (18) with hydroxylamine gave the oxime (20). X-Ray crystallography of this oxime has shown that the compound is in the ' open ' form with the "-OH group 2 to the CF3 group.…”

“…On adding bromine to a solution of compound (18) in acetic acid the hydrobromide salt of the hydrazone (23; R = Br) separated out. The 'H n.m.r.…”

“…Dilution of the methanolic mother-liquors from the isolation of the methoxy-compound (22; R1 = Me, R2 = Br) with water gave the hydroxycompound (22; R' = H, R2 = Br) and attempted recrystallisation of this alcohol from methanol regenerated the ether (22; R' = Me, R2 = Br). When compound (18) was dissolved in acetic acid and hydrogen bromide was added the hydrobromide of the hydrazone (23; R = H) separated out.…”