Lithium hydroxide, monohydrate → N-(3-phenyl-[1,2,4]thiadiazol-5-yl)-malonamic acid

Participants

Reaction Steps

To a stirred solution of 3-phenyl-[1,2,4]thiadiazol-5-ylamine (0.25 g, 0.00141 mol) in chloroform (2.5 mL) was added mono ethylmalonylchloride (0.233 g, 0.00155 mol) dropwise, the resulting mixture was stirred for 3 hours. The mixture was then concentrated and the residue was stirred in ethyl acetate. The filtrate was removed and concentrated to afford 0.26 g (63%) of N-(3-phenyl-[1,2,4]thiadiazol-5-yl)-malonamic acid ethyl ester. LC-MS purity: 292.07 (M+1)+, 67%. To a solution of N-(3-phenyl-[1,2,4]thiadiazol-5-yl)-malonamic acid ethyl ester (0.26 g, 0.00089 mol) in a mixture of methanol (3 mL) and H2O (1 mL) was added LiOH.H2O (0.112 g, 0.00267 mol). The reaction mixture was stirred for 4 hours at ambient temperature then concentrated. The resulting residue was diluted with cold water, acidified with 2NHCl and the product was extracted with ethyl acetate. The ethyl acetate layer washed with brine, dried over Na2SO4 and evaporated under reduced pressure to afford 0.105 g (45%) of N-(3-phenyl-[1,2,4]thiadiazol-5-yl)-malonamic acid. LCMS: 264.27 (M+1)+: 97.64%.

Provenance & Evidence