[en] The condensation reactions of 4-methylpyrimidine and methylpyrazine with p-anisaldehyde have been studied in NaOH 5M in the presence of catalytic amount of a quaternary ammonium salt ('quat'). This study seems to give credit to a PTC/OH extraction process where an hydroxide ion would be transferred into the 'pseudo organic phase' consisted by liquid reagents. However, an IPTC process cannot be ruled out for some of tested quats.
