Conversion process xanthine cycle or derivatives derivatives in cycle xanthine dialkylamino xanthine-type.

A process for preparing a compound of formula: wherein A is a xanthine ring or a derivative of a xanthine ring, B is a hydrocarbon group, C and D are identical or different hydrocarbon groups, optionally carrying one or more hydroxyl groups or a salt of such a compound, wherein reacting the xanthine ring or said derivative with a molar excess of a substance X1 - B - X2 with X1 and X2 electrophilic groups in the presence of a molar excess an amine of the formula: wherein optionally converting the compound formed into a salt thereof, characterized in that the reaction is carried at a temperature above 90 degrees C and at a pressure above 10 (5) Pa.