Reaction of Ph<sub>3</sub>P(SCN)<sub>2</sub>with Further Orthohydroxy Carboxylic Acid Systems, Including Substituted β-Keto Acids: Synthesis of Novel 2-Thio-1,3-oxazines and Their Subsequent Transformation with Amines
作者:Kaylene M. Pritchard、Jasim Al-Rawi
DOI:10.1080/00397910802267204
日期:2008.11.3
We now report the first reaction of Ph3P(SCN)2 with 4,6-dihydroxy-5-methylisophthalic acid to give 10-methyl-2,8-dithio-1,3-oxazino-1,3-benzoxazine-4,6-dione. Also, the enol tautomer has been utilized in the reaction of -keto acids with Ph3P(SCN)2 to give novel 2-thio-1,3-oxazines. Subsequent reaction of the 2-thio-1,3-oxazines with benzylamine resulted in opening of the oxazine ring and gave novel dibenzylamino-enamides, which could be cyclized to thiouracils. The reaction of 2-thio-1,3-oxazines with morpholine at low temperature led to the production of unstable 2-Mercapto-2-morpholino-1,3-oxazines. 2-Mercapto-2-morpholin-4-yl-2,3,5,6,7,8-hexahydro-4H-1,3-benzoxazin-4-one was observed to lose H2S at room temperature to give 2-morpholin-4-yl-5,6,7,8-tetrahydro-4H-1,3-benzoxazin-4-one, which was subsequently tested and found to exhibit some antiplatelet activity.