Synthesis of 2-amino-2-deoxo-5-deazaflavins and related compounds

10-Alkyl-2-amino-2-deoxo-5-deazaflavins were prepared by the condensation of 2-amino-6-chloro-5-formylpyrimidin-4(3H)-one with the corresponding N-alkylanilines. 2-Amino-10-p-tolyl-2-deoxo-5-deazaflavin was prepared by the condensation of 2-amino-6-p-toluidinopyrimidin-4(3H)-one with o-chlorobenzaldehyde. Some reactivities of 2-aminopyrimidin-4(3H)-ones are described.