Di:bromo-di:chloro-ethyl-cyclopropane-carboxylic acid silyl ester(s) - prepd. by reaction di:chloro-vinyl-cyclopropane-carboxylic acid with silyl halide and bromination of the prod.

摘要

New cyclopropanecarboxylic acid silyl ester derivs. are cpds. of formula (I). In (I) R is 1-4C alkyl, 2-5C alkenyl, 3-5C cycloalkyl or phenyl; and X1 is 1, 2, 3 or 4. Prepn. of (I) comprises reaction of (III) with ClX1Si(R)4-X1 and bromination of prod. (I) in which X1 is 1 and R is CH3; and (I) in which X1 is 4, are specific examples. (I) are useful as intermediates for cpds. of formula (II) (where R1 is OH, halogen, 1-4C alkoxy or a gp. of formula (IIa); R2 is H, CN, -CS-NH2, 1-4C alkyl, 2-5C alkenyl or 2-5C alkynyl; R3 is O, S or vinylene; R4 is H, 1-4C alkyl or benzyl, phenoxy or phenylthio opt. substd. by halogen, 1-4C alkyl or 1-4C alkoxy; and R5 is H, halogen or 1-4C alkyl). (II) are useful as insecticides or intermediates for insecticides.