Guanidine Hydrochloride → 2-methyl-4,5-dihydro-[1,3]thiazolo[4,5-h]quinazolin-8-amine

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A mixture of 2-methyl-6-morpholin-4-ylmethylene-5,6-dihydro-4H-benzothiazol-7-one (2.24 g, 8.47 mol), guanidine hydrochloride salt (0.89 g, 9.32 mol) and NaOH (0.37 g, 9.32 mol) in EtOH (150 mL) was heated under reflux for 4 h. The reaction mixture was concentrated under vacuum. Flash column chromatography (50% EtOAc:hexane) afforded the title product as a yellow solid (1.66 g, 90%): mp 241-243° C. Anal. RP-HPLC: tR 8.7 min (0-60% MeCN, purity 100%). 1H-NMR (CDCl3): δ 8.06 (s, 1H, Py-H), 5.01 (brs, 2H, NH2), 2.99 (m, 4H, CH2—CH2), 2.76 (s, 3H, CH3). MS (ESI+): m/z 219.02 (M+H)+.

Provenance & Evidence