The position of O-alkylation can be varied by suitable choice of reagent. Thus, NaH in DMSO followed by MeI gives predominantly the 2-alkylated product, whereas Li2CO3 in DMF favors 4-alkylation. The latter is a fairly general method for the alkylation of phenols, thiophenols and ?-diketones with pKa less than about 8: Synth. Commun., 18, 1379 (1988).