| 摘要 |
The subject matter of the invention is a process for the preparation of carboxylic acids and derivatives of them of the general formula <CHEM> wherein R means hydrogen, or a C1-4alkyl or a (C1-5alkoxy)carbonyl group, R1 is as defined in claim 1, R7 stands for hydrogen or a C1-7alkyl group and R8 means hydrogen or a carboxyl group, by reacting a 1,3-dioxane-4,6-dione derivative of the general formula <CHEM> wherein R9 stands for a C1-4alkyl group or a phenyl group, optionally monosubstituted by halogen and R10 stands for hydrogen or a C1-5alkyl group or R9 and R10 together form a pentamethylene group, and an aldehyde or ketone of the general formula <CHEM> in the presence of formic acid and of [a] amine(s) and, if desired, of an alcohol of the general formula R7 - OH VI, wherein R7 is a C1-7alkyl group, at a temperature of 20 to 140 DEG C, and/or reducing an unsaturated 1,3-dioxane-4,6-dione derivative of the general formula <CHEM> and/or a 1,3-dioxane-4,6-dione derivative of the general formula <CHEM> with formic acid in the presence of [a] amine(s) and, if desired, of an alcohol as above defined. |
