Synthesis and structure of substituted triazoloquinazolines
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Carbonyl-substituted hydroxycyclohexanones such as diethyl 2-Ar-4-hydroxy-4-methyl-6-oxocyclo-hexane-1,3-dicarboxylates (1) and 3-Ar-2,4-diacetyl-5-hydroxy-5-methylcyclohexanones (2) are commonly used for the construction of condensed systems containing a five-membered heterocycle . There have been only a few examples of the construction of six-membered heterocycles starting from such reagents.
We have studied the reaction of carbonyl-substituted hydroxycyclohexanones 1a-c and 2 with 3-amino-1,2,4-triazole. The presence of several nucleophilic sites in the reagent and their arrangement should be conducive for the annelation of a six-membered heterocycle and generation of systems possessing different types of ring fusion and possessing of the nitrogen atoms at different positions.
Heating equimolar amounts of the reagents at 120-140°C without solvent gave previously unreported triazoloquinazolines: ethyl 6-Ar-5,8-dihydroxy-8-methyl-6,7,8,9-tetrahydro[1,2,4]triazolo[3,4-b]quinazoline-...