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Bupirimate is a pyrimidine based fungicide with protective and curative activity for the control of fungal diseases by interfearing with nucleic acid synthesis.

Bupirimate is a systemic fungicide that provides protective and curative control of powdery mildew (Podosphaera leucotricha) mainly in pome fruits, stone fruits and glasshouse roses. Other uses include berries, vines and cucurbits.

Fungicide.

ChEBI: A member of the class of aminopyrimidines that is 2-ethylaminopyrimidine carrying methyl, butyl and dimethylaminosulfooxy substituents at posiitons 4, 5 and 6 respectively.

Bupirimate degrades rapidly when exposed to sunlight. Minimal penetration of bupirimate residues in treated apples was observed. Degradation of bupirimate in/on fruit surfaces was mainly due to photolytic processes. Metabolism in plants and animals is similar and includes the initial cleavage of the dimethylsulfamate-pyrimidine linkage to yield ethirimol which is also an active fungicide. Numerous degradation products were generated from N-dealkylation, hydroxylation and conjugation reactions and the opening of the pyrimidine ring (Scheme 1).

Bupirimate (1) is stable in dilute alkaline solution, but readily hydrolysed in dilute acidic solution. Bupirimate was rapidly decomposed in aqueous solution when exposed to sunlight (Hassall, 1982). Cleavage of the dimethylsulfamate-pyrimidine linkage yielded ethirimol [5-butyl-2- ethylamino-6-methylpyrimidin-4-ol (2)] as the major product. Ethirimol, an active fungicide, was degraded slowly under these test conditions. Four additional minor products were also detected. Three of these products were identified aS isomers of bupirimate, resulting from the migration of the dimethylsulfamate moiety to the various nitrogen molecules (compounds 3, 4 and 5; Cavell and Lincoln, 1974; Teal and Skidmore, 1976).