Phenyl(pyridazin-4-yl)methanone → 4-methyl-N'-[phenyl(pyridazin-4-yl)methylidene]piperazine-1-carbothiohydrazide

Participants

Reaction Conditions

Reaction Steps

A mixture of phenyl-pyridazin-4-yl-methanone (12; Synthon A, 2.3 g, 12.4 mmol) and 4-Methylpiperazine-1-carbothioic acid hydrazide (6; Synthon B, 2.82 g, 16.18 mmol) in ethanol (7.5 mL) was heated to 65° C. for 5 h under N2 in a 50 mL pyrex tube equipped with a screw cap. The mixture remained heterogeneous during the heating and a brown suspension resulted at the end of the reaction. The mixture was diluted with CH2Cl2 (7.5 mL) and was chromatographed on silica gel that was eluted with MeOH/CH2Cl2 (2.5-5%) to give 1.8 g of a yellow foamy solid 1A (99.3% pure by HPLC); m.p. 141-143° C. (m.p. of a crystalline sample 143-145). TLC (CH2Cl2/MeOH/NH4OH:95/5/0.5): Rf=0.6, product is visibly yellow, UV and Dragendorff stain active. MS (ESI+): [M+H]+=340.93. HRMS: m/z calcd. for C17H21N6S ([M+H]+): 341.15429; found: 341.15501. 1H NMR (300 MHz, CDCl3), δ ppm: 2.38 (s, 3H), 2.61 (t, 4H, J=5.0 Hz), 4.12 (t, 4H, J=5.0 Hz), 7.29 (m, 3H), 7.63 (m, 3H), 8.64 (s, 1H), 9.14 (dd, 1H, J=5.7 Hz, J′=1.5 Hz), 9.44 (dd, 1H, J=2.4 Hz, J′=1.5 Hz). 13C NMR (75.4 MHz, CDCl3), δ ppm: 45.75, 51.64, 54.75, 123.30, 128.29, 128.39, 130.40, 131.10, 134.86, 143.94, 148.31, 151.31, 181.49.

Provenance & Evidence