TLC: Rf = 0.35 [S1], yield: 42% (Procedure B), 53% (Procedure C), m.p. 170˚C - 172˚C. IR ν (cm−1): 3338 (NH), 1657 (C=O amide). 1H NMR (DMSO-d6, δ, ppm): 2.13 (s, 3H, NCH3), 2.27 - 2.39 (m, 4H, 2CH 2, Pip-H), 2.41 - 3.51 (m, 4H, 2CH2, Pip-H), 4.01 (s, 2H, COCH2), 6.51 (d, J = 15 Hz, 1H, =CHCO), 6.98 (t, J = 3.5 Hz, 1H, Th-H4), 7.15 (d, J = 5 Hz, 1H, Th-H3), 7.50 (d, J = 15
Hz, 1H, CH=CH), 7.56 (d, J = 5 Hz, 1H, Th- H5), 8.18 (s, 1H, NH, exchangeable with D2O). Mass: m/z 294 ([M+1]+, 12%). Calcd. for C14H19N3O2S (293.38). Calcd. C 57.31, H 6.53, N 14.32, S 10.93. Found: C 57.22, H 6.45, N 14.22, S 10.86.