| 摘要 |
Pyrazolo[1,5a]pyrimidines of the following general structure are disclosed which are useful as inhibitors of phosphodiesterase enzymes, WHEREIN R and R' are the substituents defined hereinafter. Such compounds may be prepared by condensation of 3-aminopyrazole with diethyl ethoxymethylenemalonate to afford 6-carbethoxy-7-hydroxypyrazolo[1,5a]pyrimidine which, when heated with phosphorous oxychloride under appropriate conditions, gives 6-carbethoxy-7-chloropyrazolo[1,5a]pyrimidines, which, when treated with nucleophilic reagents produce 6-carbethoxy-7-substitutedpyrazolo[1,5a]pyrimidines. The treatment of 6-carbethoxy-7-substitutedpyrazolo[1,5a]pyrimidines with electrophilic reagents produces the corresponding 3,7-disubstituted-6-carbethoxypyrazolo[1,5a]pyrimidines. Condensation of various 4-substituted-3-aminopyrazoles with ethyl ethoxymethylene-cyanoacetate affords 6-carbethoxy-7-amino-3-substitutedpyrazolo[1,5a]pyrimidines.
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