Synthesis of Some 2-Substituted Quinazolin-4(3H)-one Compounds from Methyl α-[(4-oxoquinazolin-2-yl)thio]acetate

Abstract A series of new quinazoline-4(3H)-one derivatives (2-16) have been synthesized using methyl α-[(4-oxoquinazolin-2-yl)thio]acetate (1) as precursor. The corresponding hydrazide (2) and thiosemicarbazide (4) were from this ester via the reaction with hydrazine hydrate ammonium thiocyanate respectively. was employed to synthesize 2-amino-1,3,4-thiadiazole (5) 1,3,4-triazole-5-thiol (6) its cyclization under acidic basic conditions On other side, organic thiocyanates would be afforded di-substituted (13-15), while carbon disulfide in existence potassium hydroxide carbodithioate salt (7). (7) treated give 1-amino-1,3,4-triazol-2-thiole compound (8). later (8) used a precursor fused heterocyclic compounds {namely 1,2,4-triazolo[3,4,b][1,3,4]thiadiazolin-6-thiol (9), 1,2,4-triazolo[3,4,b][1,3,4]-6-methylthiadiazoline (10) 1,2,4-triazolo[3,4,b][1,3,4]-6-arylthiadiazoline (11, 12)} CS2 / hydroxide, acetyl chloride aromatic aldehydes Elucidation structures (4-16) performed FT-IR, 1H-NMR 13C-NMR spectroscopic methods.