Phosphoric Acid → 2-(5-Amino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetic acid
Reaktionsgleichung
[NH2:1][C:2]1[S:6][N:5]=[C:4]([C:7](=[N:10][O:11][CH3:12])[C:8]#N)[N:3]=1.[OH:13]P(O)(O)=O.[OH-:18].[Na+]>>[NH2:1][C:2]1[S:6][N:5]=[C:4]([C:7](=[N:10][O:11][CH3:12])[C:8]([OH:13])=[O:18])[N:3]=1Komponenten
4
Versuchsvorschrift
A mixture of 2-(5-amino-1,2,4-thiadiazol-3-yl-2-methoxyiminoacetonitrile (18.3 g, 0.1 mole) in 4N NaOH (250 ml) was heated at 50°-55° C. with stirring for 3 hours. The reaction mixture was adjusted to pH 1 with H3PO4, and washed with ethyl acetate (100 ml), saturated with NaCl, and extracted three times with a mixture of ethyl acetate and tetrahydrofuran (3:1, 300 ml×2, and 200 ml×1). The extracts were combined, dried over MgSO4 and concentrated under reduced pressure. The residue was triturated with isopropyl ether to afford pale yellow crystals of the title acid. Yield 16.8 g (83%). M.p. 184°-5° C. (dec.). [Lit.*, m.p. 180°-182° C. (dec.)].