| 摘要 |
A process for the preparation of a compound of formula and/or an addition salt of a proton acid, wherein R<SUP>1 </SUP>and R<SUP>2 </SUP>independently represent alkyl, cycloalkyl, aryl or aralkyl, each aryl or aralkyl being optionally further substituted with alkyl, alkoxy and/or halogen, which process comprises the following steps: (a) reacting a mixture comprising (i) a methyl ketone of formula wherein R<SUP>1 </SUP>is as defined above, and (ii) a compound of formula <?in-line-formulae description="In-line Formulae" end="lead"?>H<SUB>2</SUB>N-R<SUP>2 </SUP> (V) <?in-line-formulae description="In-line Formulae" end="tail"?> and/or an addition salt of proton acid, wherein R<SUP>2 </SUP>is as defined above, and (iii) formaldehyde or a source of formaldehyde selected from the group consisting of formaldehyde in aqueous solution, 1,3,5-trioxane, paraformaldehyde and mixtures thereof, in the presence of a solvent selected from the group consisting of water, aliphatic alcohols, cycloaliphatic alcohols and mixtures thereof, and optionally a proton acid to afford a beta-amino ketone of formula and/or an addition salt of a proton acid, and (b) reducing the carbonyl group of said beta-amino ketone to afford a compound of formula I, and/or an addition salt of a proton acid wherein the first step is carried out at a pressure above 1.5 bar.
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