Abstract: A Rhodotorula rubra strain has been found which reduces pentoxifylline to 100% to give the S-alcohol. Moreover, other oxoalkylxanthine derivatives can also be convened into the corresponding S-alcohol. The microbiologically obtained S-(+)-enantiomers can then be converted stereoselectively into the respective R-(-)-enantiomers. The corresponding S-alcohols and the R-alcohols obtained by enantioselective inversion of configuration cause an increase in cerebral blood flow.

Abstract: A Rhodotorula rubra strain has been found which reduces pentoxifylline to 100% to give the S-alcohol. Moreover, other oxoalkylxanthine derivatives can also be converted into the corresponding S-alcohol. The microbiologically obtained S-(+)-enantiomers can then be converted stereo-selectively into the respective R-(-)-enantiomers. The corresponding S-alcohols and the R-alcohols obtained by enantioselective inversion of configuration cause an increase in cerebral blood flow.

Abstract: A Rhodotorula rubra strain has been found which reduces pentoxifylline to 100% to give the S-alcohol. Moreover, other oxoalkylxanthine derivatives can also be converted into the corresponding S-alcohol. The microbiologically obtained S-(+)-enantiomers can then be converted stereoselectively into the respective R-(-)-enantiomers. The corresponding S-alcohols and the R-alcohols obtained by enantioselective inversion of configuration cause an increase in cerebral blood flow.

Abstract: Compounds of the formula ##STR1## wherein one of the radicals R.sup.1, R.sup.2 or R.sup.3 denotes a straight-chain alkyl group having 4 to 8 C atoms and two vicinal hydroxyl groups in the .omega.,.omega.-1 or .omega.-1,.omega.-2 positions and the two other radicals represent straight-chain or branched alkyl groups having up to 12 C atoms in the position of R.sup.1 and R.sup.3 and up to 4 C atoms in the position of R.sup.2, the total of C atoms in these two alkyl substituents being a maximum of 14, are prepared by oxidation of the corresponding alkenylxanthines and by alkylation with compounds which introduce the dihydroxyalkyl radical or a precursor thereof. The dihydroxyalkyldialkylxanthines are suitable for the treatment of obstructive respiratory tract diseases.

Abstract: A pharmaceutical composition containing as an essential ingredient a compound of the formula ##STR1## wherein one of the groups R.sub.1, R.sub.2 and R.sub.3 is an .omega.- or (.omega.-1)-hydroxyalkyl group having from 5 to 8 carbon atoms in which the hydroxy group is separated from the xanthine nucleus by at least 2 carbon atoms, radicals R.sub.1 and R.sub.3 which are no hydroxylalkyl group, are hydrogen or methyl and equal or different, and R.sub.2 is said hydroxyalkyl group or methyl, a compound of formula (I) and a pharmaceutical product for treatment of diseases involving insufficiency of cerebral blood flow.

Abstract: A pharmaceutical composition containing as an essential ingredient a compound of the formula ##STR1## wherein one of the groups R.sub.1, R.sub.2 and R.sub.3 is an .omega.- or (.omega.-1)-hydroxyalkyl group having from 5 to 8 carbon atoms in which the hydroxy group is separated from the xanthine nucleus by at least 2 carbon atoms, radicals R.sub.1 and R.sub.3 which are no hydroxyalkyl group, are hydrogen or methyl and equal or different, and R.sub.2 is said hydroxyalkyl group or methyl, a compound of formula (I) and a pharmaceutical product for treatment of diseases involving insufficiency of cerebral blood flow.

Abstract: A pharmaceutical composition having as an essential ingredient a compound of the formula ##STR1## wherein one to three of R.sup.1, R.sup.2 and R.sup.3 represent an alkenyl group having from 4 to 8 carbon atoms, the other ones are alkyl having from 1 to 12 carbon atoms, and R.sup.1 may also be hydrogen, the compounds themselves and a process for preparing them.

Abstract: Compound of the formula ##STR1## wherein one of the groups R.sub.1, R.sub.2 and R.sub.3 is a hydroxyalkyl group containing from 4 to 8 carbon atoms, one of the other two, which may be the same or different, is an alkyl group containing from 2 to 12 carbon atoms and the third one is an alkyl group containing from 1 to 12 carbon atoms or a hydrogen atom, R.sub.2 however being an alkyl or hydroxyalkyl group, at least one of the groups R.sub.1, R.sub.2 and R.sub.3 containing at least 5 carbon atoms, a process for their preparation and a pharmaceutical composition containing said compounds.