Non-catalytic alkylation of aniline with 1,3,5-trimethyl-4-hydroxymethylpyrazole

H. S. Attaryan 0 V. I. Rstakyan 0 S. S. Hayotsyan 0 G. V. Asratyan 0 0 Institute of Organic Chemistry of Scientific Technological Centre of Organic and Pharmaceutical Chemistry, National Academy of Sciences of Armenia , Azatutyan ave. 26, Yerevan, 0014 Armenia The electron density in the benzene ring, preferably in the ortho- and para-positions, is known to be increased in benzenes containing activating groups as substituents. For this reason, the reaction of electrophilic substitution in anilines, phenols, alkylbenzenes, and related derivatives occurs in the orthoand para-positions of the ring [1]. As it was shown earlier [2], the noncatalytic alkylation of phenol with 1,3,5-trimethyl-4-hydroxymethylpyrazole I proceeded similarly to give C-alkylation products as a mixture of ortho-and para-isomers with a yield of 67%. - The structure of compound II was confirmed by the IR, 1H and 13C NMR spectroscopy and its composition, by the elemental analysis data. N-(1,3,5-Trimethyl-1H-pyrazol-4-yl)methylaniline (II). A mixture of 6.0 g of 4-hydroxymethyl-1,3,5trimethylpyrazole I and 65 g of aniline was refluxed for 10 h. Aniline excess was removed, to the residue 10 ml of water and 100 ml of diethyl ether was added. The organic layer was separated, dried over MgSO4, and evaporated. The residue was distilled in a vacuum. Yield 5.0 g (54%), bp 190192C (1 mm Hg), mp 95 100C (isopropanol). IR spectrum, , cm1: 1550 (pyrazole), 1600 (phenyl), 3300 (NH). 1 NMR spectrum, , ppm: 2.12 s (3H, 3-CH3), 2.22 s (3H, 5CH3), 3.66 s (3H, N-CH3), 3.89 br. s (2H, CH2), 4.78 br.s (1H, NH), 6.51 t.t (1H, H4, C6H5, 3J 7.3, 4J 1.1 Hz), 6.56 m (2H, H2,6, C6H5), 7.03 m (2H, H3,5, C6H5). 13C NMR spectrum, , ppm: 9.0 and 11.2 (3,5CH3), 35.0 (1-CH3), 37.1 (CH2), 111.8 (C2,6, C6H5), 112.8 (C4, pyrazole), 115.5 (C4, C6H5), 128.2 (C3,5, C6H5), 136.2 (C1, C6H5), 144.6 and 148.4 (C3,5, pyrazole). Found, %: 72.18; 7.31; N 19.85. 1317N3. Calculated, %: 72.55; 7.90; N 19.53. The IR spectra were registered on a Specord 75 IR spectrophotometer from thin film. The 1 and 13C NMR spectra were recorded on a Varian Mercury-300 instrument (300 MHz) in DMSO-d6. (...truncated)