New and practical method for synthesis of 1- and 1,3-substituted xanthines.

[reaction: see text] A new and practical method for the synthesis of 1- and 1,3-substituted xanthines is reported. Direct base-promoted condensation of the imidazole precursor 1 with carbamates 2 gives 1-substituted 7-PMB xanthines 7 in good yields. Alkylation of these derivatives or their potassium salts proceeds under mild conditions to give functionalized 1,3-substituted 7-PMB xanthines 9 in good to excellent yields.

Aziridines and aziridinium ions in the practical synthesis of pharmaceutical intermediates--a perspective.

Recent methods for the synthesis of aziridines and aziridinium ions, the mechanisms of their nucleophilic ring-opening reactions and applications to the practical synthesis of pharmaceutical intermediates are reviewed.