H, m). m/e(%) 146 (36.0), 131 (22.3), 105 (100.0), 77 (50.3), 69 (44.6). This product was not purified (lit.18 bp 90-95 °C (2 mmHg)).2-(2-Benzoyl-l-methylethyl)-3,5-diphenylpyrrole (29a).The sublimed product from the pyrolysis of 15a and 16 (0.12 g) was dissolved in CDC13 (0.5 mL) and the reaction was monitored by NMR. After 5-6 days at 25 °C the formation of 28a was completed. Addition of HBF4 (48%, 2 drops) gave 29a in 1 h. Removal of the solvent gave the adduct as a viscous oil: IR (CHBr3) 3430 m (NH), 1672 s (C=0) cm"1; NMR (CDC13) 1.5(3 H, d, J = 7 Hz), 3.4 (2 H, m), 3.6-4.S (1 H, m), 6.5 (1 H, d, J = 3 Hz), 7.0-8.1 (15 H, m), 8.6 (1 H, d, NH); 13C NMR (CDC13) 20.3 (q), 27.4 (d), 45.0 (t), 106.35 (d), 123.5-137.1 (aromatic C), 200.4 (s); m/e (%) 365 (24.7), 246 (100.0), 105 (48.0); high-resolution MS, m/e caled for C26H23NO, 365.1772; found, 365.1776. 2-(2-Benzoylethyl)-3,5-diphenylpyrrole (29b). Pyrolysis of 15b (0.3 g, 0.85 mmol) as above at 170-190 °C (1-5 mmHg) gave 0.18 g of a mixture of 27 and 29b. The adduct 29b (50 mg, 17%) was isolated by fractional recrystallization from EtOH: needles; mp 132-133 °C; IR (CHBr3) 3450 m (NH), 1680 s (C=0) cm'1;