| CPC C07D 403/14 (2013.01) | 18 Claims |
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1. A process for the preparation of a compound of formula
![]() wherein R1 and R2 are independently from each other C1-C8alkyl, comprising reacting a compound of formula
![]() with a formaldehyde source in presence of a palladium or platinum catalyst at a hydrogen pressure of 5×108 mPa to 200×108 mPa.
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