Hb. Lazrek et al., SOLID-LIQUID PHASE-TRANSFER CATALYSIS .2. A CONVENIENT APPROACH TO THE SYNTHESIS OF ACV, HBG AND RELATED-COMPOUNDS, Bulletin des Societes chimiques belges, 105(7), 1996, pp. 391-395
When solid-liquid phase transfer catalysis is conducted in the presenc
e of potassium tert-butoxide as base, 18-crown-6 ether or tetraglyme a
s catalyst, DMF as solvent and at temperature of 0 degrees C, the N-al
kylation takes place at the N-1 and N-9 in pyrimidine and purine heter
ocyclic respectively.