PROCESS FOR THE PREPARATION OF SUBSTITUTED CYCLOPROPANECARBALDEHYDES

摘要

The invention relates to a process for the preparation of cyclopropanecarbaldehydes of formula (I) in which R1 is C1-C4alkyl or benzyl, which comprises (a) reacting a tetrahydrofuran of formula (II) in which X is halogen and R2 is unsubstituted or halo-substituted C1-C10alkyl, C3-C6-cycloalkyl that is unsubstituted or substituted by halogen, C1-C4alkyl or by C1-C4alkoxy, or phenyl or benzyl each of which is unsubstituted or substituted by halogen, C1-C4alkyl, C1-C4alkoxy, nitro or cyano, with a halogenating agent to form a 1,2,4-trihalobutyl ether of formula (III) in which X is halogen and R2 is unsubstituted or halo-substituted C1-C10alkyl, C3-C6cycloalkyl that is unsubstituted or substituted by halogen C1-C4alkyl or by C1-C4alkoxy, or phenyl or benzyl each of which is unsubstituted or substituted by halogen, C1-C4alkyl, C1-C4alkoxy, nitro or cyano, and (b) then reacting the compound of formula III with an aqueous bisulfite solution to form a bisulfite adduct of formula (IV) in which X is a halogen and Y is a cation equivalent of an alkali metal or alkaline earth metal ion, and (c) then cyclising the adduct, in the presence of a base, with a thiolate of formula R1-S(-) Z(+)(V) in which R1 is C1-C4alkyl or benzyl and Z is a cation equivalent of an alkali metal or alkaline earth metal ion, to form a cyclopropanecarbaldehyde of formula I, and to the individual Process Steps (a), (b) and (c) and the combinations thereof (a)+(b) and (b)+(c), and to the novel intermediates of formulae III and IV.