PROCESSO PARA A OBTENCAO DE 3,7-DIALQUILXANTINAS A PARTIR DE 3-ALQUILXANTINAS

Production of 3,7-dialkyl-xanthines (I) comprises alkylating salts of 3-alkylxanthines (II) in the presence of a virtually water-insoluble quaternary ammonium compound (III) and in a two phase liquid reaction system comprising water and (III). Production of 3,7-dialkyl-xanthines of formula (I) comprises converting 3-alkylxanthines of formula (II) into salts by treating with a base and then alkylating the salts in the presence of a quaternary ammonium compound (III) which is sparingly soluble or insoluble in water and in a two phase liquid reaction system where one phase contains water and the other phase contains (III). (III) is present in an amount of 5-100 mol per 100 mol (II). R1, R2 = 1-6C alkyl; R3-R6 = 1-20C alkyl, benzyl or phenyl; X = an anion.