
%0 Journal Article
%A Huppatz, JL 
%T Systemic Fungicides. The Synthesis of Pyrazolo[1,5-<i>a</i>]pyrimidine Analogues of Carboxin
%J Australian Journal of Chemistry
%D 1985/01/01
%V 38
%N 1
%P 221-230
%K 
%R https://doi.org/10.1071/CH9850221
%U https://www.publish.csiro.au/paper/CH9850221 
%X The synthesis of a series of pyrazolo [1,5-a] pyrimidine derivatives, structural analogues of the systemic fungicide carboxin, is described. A common intermediate incorporating structural features desirable for fungicidal activity, N-phenyl-3(5)-amino-5(3)-methylpyrazole-4- carboxamide (6), was used to prepare pyrazolo [1,5-a] pyrimidines variously substituted in positions 5 and 7 of the ring system. Bromination of N-phenyl-2-methylpyrazolo[1,5-a]pyrimidine-3-carboxamide (8) occurred preferentially in the phenyl ring and the 6-bromo derivative was prepared by bromination of the corresponding 3-ethoxycarbonyl derivative (24). Attempted nitration of the ester (24) resulted in displacement of the ethoxycarbonyl substituent by a nitro group. The simplest pyrazolo [1,5-a] pyrimidine (8) showed a high level of fungicidal acitvity in fungal growth assays of Basidiomycete species, but compounds substituted in the pyrimidine ring were inactive. 
