SYNTHESIS OF SUBSTITUTED PYRAZOLO [1,5-A] PYRIMIDINES

The reaction of 3-amino-4-cyanopyrazole (1) with ethyl acetoacetate, a cetyl acetone, and ethyl cyanoacetate give pyrozoIo[1,5-a]pyrimidine d erivatives 2, 4, and 7 respectively. Compound 2 reacts with phosphorou s oxychloride to give the corresponding 7-chloro derivative 3. Compoun d 4 reacts with hydroxyl amino to give N-hydroxy-3-carboximidamide 5 w hich was converted by acetic anhydride to 3-(5-methyl-1,2,4-oxadiazol- 3-yl) derivative 6. Coumpound 1 also react with diethyl malonate to gi ve N,N-bis(4-cyano-5-pyrazoly) malonamide 8 and ethyl(4-cyano-5-pyrazo lyl) malonamide 9. Ethyl(4-cyano-5-pyrazolyl) malonamidate 9 with acet ic acid yielded pyrazolo[1,5-a] pyrimidine derivative 10. Other member s of this ring system results from treatment of 1 with arylidine malon onitrile, and ethyl arylidine cyanoacetate derivatives to yield compou nds 11, and 12 respectively. Compound 1 reacts with activated acetylen e to give pyrazolo [1,5-a]pyrimidine derivatives 13a and 13b.