Synthesis and unusual chemical reactivity of certain novel 4,5-disubstituted 7-benzylpyrrolo[2,3-d][1,2,3]triazines.
Synthesis and unusual chemical reactivity of certain novel 4,5-disubstituted 7-benzylpyrrolo[2,3-d][1,2,3]triazines.
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DOI：
10.1021/jo001499i
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发表时间：
2001-07
期刊：
影响因子：
--
通讯作者：
M. Migawa;L. Townsend
中科院分区：
文献类型：
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作者：
M. Migawa;L. Townsend
The fact that only two pyrrolo[2,3-d][1,2,3]triazines heterocycles had been reported in the literature prompted us to initiate studies designed to provide additional members of this ring system. Initial attempts to prepare additional derivatives of the 7-unsubstituted pyrrolo[2,3-d][1,2,3]triazin-4-ones were limited by their low chemical reactivity. Subsequently, 7-benzyl-5-carboxamidopyrrolo[2,3-d][1,2,3]triazin-4-one (16) was prepared from diethyl 2-nitropyrrole-3,4,-dicarboxylate via an alkylation, ammonolysis, reduction and intramolecular diazocoupling sequence. Conversion of 16 into 7-benzyl-4-(1,2,4-triazol-1-yl)pyrrolo[2,3-d][1,2,3]triazine-5-carbonitrile (17) was accomplished, and nucleophilic displacements of the 4-triazol-1-yl group were studied. Treatment of 17 with NH3/CH3CN gave a mixture of 4-amino-7-benzylpyrrolo[2,3-d][1,2,3]triazine-5-carbonitrile (19) and 2-amino-1-benzylpyrrole-3,4-dicarbonitrile (21). A mechanism to account for the formation of this mixture is described along with studies on the effect that ammonia concentration and a TFA catalyst have on the product ratio. Compound 19 was converted into the 5-carboxamide and 5-thioamide derivatives of 19.
