| 摘要 |
Quat ammonium salts of opt C5-substd 2-thiobarbituric acid derivs of formula (I) and their tautomeric forms are new. R1 and R2 = H, aryl, alkyl or benzyl; R3-R6 = alkyl, phenyl or benzyl. (I) can be prepd by (a) reacting a quat ammonium halide of formula XNR3R4R5R6 (II) in soln or suspension in a solvent, pref in an alcoholic medium, with an alkali alcoholate; (b) removing the alkali halide formed; and (c) reacting the quat ammonium alcoholate formed with a 2-thiobarbituric acid of formula (III) or with one of its tautomeric forms, or reacting the quat ammonium alcoholate with thiourea and a malonic acid dialkylester of formula R00C-CR1R2-C00R (IV) (R=alkyl). USE/ADVANTAGE - (I) are intermediates in the prepn of thio-barbituric acid derivs (such as 2-(methylthio)-barbituric acid) which are themselves intermediates in the prepn of pharmaceuticals, insecticides and fungicides. (I) are better soluble in organic solvents than the corresp alkali salts, thus facilitating the use of organic rather than aq reaction media, leading to higher reaction rates or improved selectivity and avoiding the need to dispose of aq wastes.
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