| abstract |
The invention relates to an improved method for producing enantiomer-free 8-(3-amino-piperidin-1-yl)-xanthines. In particular, the invention relates to a process for preparing a compound of the general formula (I) (see formula I) or an enantiomer thereof wherein R1, R2 and R3 are as defined in the claims. The process includes the reaction of a compound of formula (III) (see formula III) in which X is a leaving group as defined in the claims with 3-(phthalimido)piperidine, followed by deprotection of the thus obtained compound of general formula (II) (see formula II) In addition, the invention relates to medicaments comprising the compound of formula (I) and uses for treating diabetes mellitus I, diabetes mellitus II, prediabetes, reduction of glucose tolerance, arthritis, obesity, allograft transplantation or osteoporosis caused by calcitonin. |