5-Methyl-3-isoxazolecarboxamide → 5-Methylisoxazole-3-carbothioamide
Reaction equation
[CH3:1][C:2]1[O:6][N:5]=[C:4]([C:7]([NH2:9])=O)[CH:3]=1.COC1C=CC(P2(SP(C3C=CC(OC)=CC=3)(=S)S2)=[S:19])=CC=1>C1(C)C=CC=CC=1>[CH3:1][C:2]1[O:6][N:5]=[C:4]([C:7](=[S:19])[NH2:9])[CH:3]=1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
A suspension of 525 mg (4.16 mmol) of 5-methylisoxazole-3-carboxamide and 1.85 g (4.58 mmol, 1.1 equiv) of Lawesson's reagent in 15 mL of dry toluene was heated to reflux for 5 h, during which time the reaction mixture became a clear yellow color. The reaction mixture was cooled to RT and the solvent was removed in vacuo. Purification of the material by silica gel flash column chromatography using a gradient of hexane/EtOAc 5/1 to hexane/EtOAc 1/1 as eluent followed by trituration with acetonitrile, filtration to remove the solid Lawesson's reagent byproducts and removal of solvent afforded 614 mg of the title compound as a yellow oil: 1H NMR (CDCl3, 300 MHz) δ 8.05 (s, br, 2H), 6.52 (s, 1H), 2.46 (s, 3H).