Based upon the fact that 7-amino-3, 6-dimethylpyrazoio[1, 5-a]pyrimidirie (XIII) possesses effective antipyretic and analgetic action, 14 methyl substitutes of 7-aminopyrazolo[1, 5-a]-pyrimidine in its nuclei were synthesized. With 5-aminopyrazoles (VII-X), 2-methyl-3-ethoxy-3-methoxypropionitrile (I) was reacted to give 6-methyl compounds (XI-XIV), acetoacetonitrile (III) was reacted to give 5-methyl derivatives (XV-XVIII), 2-acetopropionitrile (IV) to 5, 6-dimethyl derivatives (XIX-XXII), and ethyl ethoxymethylenecyanoacetate (V) to 6-ethoxycarbonyl derivatives (XXVII-XXX). In this connection, the cyclization with V in both acidic and alkaline media, and the saponification of XXVII-XXX were investigated. The thermal decomposition of XXXV-XXXVIII produced decarboxyl compounds (XXXIX-XLII) easily. Another synthetic method of XLII was also studied.