Process for the preparation of 3,7-dialkylxanthines
AssigneeBASF SE
InventorsMarius Bugglin, Herbert Gropp, Lothar Janitschke, Ulrich Karl, Hans-Heinrich Lenz
Life of this patent
Estimating the term…
Abstract
The invention is directed to a process for preparing 3,7-dialkylxanthines of the formula I ##STR1## (R.sup.1 and R.sup.2 denote C.sub.1 -C.sub.4 -alkyl) by the reaction of 4-amino-imidazolecarboxamide-(5) of the formula II ##STR2## with an alkali cyanate in aqueous solution at a pH of from 3 to 5 followed by cyclization of the resulting urea derivative at a pH of from 8 to 14.
Claims1
A process for the preparation of a 3,7-dialkylxanthine of the formula I ##STR8## in which R.sup.1 and R.sup.2 denote C.sub.1 -C.sub.4 -alkyl, wherein a 1-alkyl-4-alkylamino-5-alkylaminocarbonylimidazole of the formula II ##STR9## in which R.sup.3 denotes C.sub.1 -C.sub.4 -alkyl, is reacted with an alkali metal cyanate in aqueous solution at a pH of from 3 to 5, and the resulting urea derivative is subjected to cyclization at a pH of from 8 to 14 to form the corresponding 3,7-dialkylxanthine (I).
Dependencies are inferred from the claim text.