3026-99-1

Perfluoroalkylated indoles are valuable compounds in drug discovery. A Pd(0)-catalyzed C(sp3)-H functionalization enables access to 2-(trifluoromethyl)indoles from trifluoroacetimidoyl chlorides. These are stable compounds, easily obtained from

Selective acetylation of the less hindered amino group in the presence of the more hindered amino group with the use of 2-trifluoromethyl-N,N-diacetylaniline 2c is described. This acetylation with 2c yielded the corresponding less hindered monoacetamide exclusively, simply, conveniently, and in good yields.

A number of diacetanilides, including some which have not been reported so far, have been synthesized from the corresponding monoacetyl derivatives and characterized by spectral and elemental analyses.A tlc/fid method for the quantitative estimation of the relative amounts of mono- and diacetyl derivatives has been standardized.Linear correlation of the extent of diacetylation with Hammett ?-values of substituents and basicity constants of monoacetyl derivatives has been established.A plausible mechanism for the diacetylation reaction based on experimental observations has been suggested.An explanation for the anomalous behaviour of acetanilides containing electron-withdrawing substituents in the ortho-position has been put forth.

Procedures are described for a one-pot synthesis of 1H-indazole and substituted indazoles 3 in good yield (Table 1) from o-toluidines 2, alkyl nitrite or nitrous oxides, potassium acetate, and acetic anhydride in benzene.The spectroscopic properties of substituted indazoles (Tables 2-4) are discussed. - 4-Phenylcinnoline (18) is prepared by the same procedure from o-(α-methylenebenzyl)aniline.