The lithium salts of the conjugated bases of 4-methoxy-and 4-acetylamino-2 (1H)- pyrimidinones 1–3 undergo highly chemoselective N1-methylation or ethylation when treated with methyl-or ethylsulfate (hard electrophiles) in dry dioxane, while the use of DMF as solvent results in competitive O2-alkylation. Potassium salts of the same bases in DMF undergo prevalent O2-attack. Under the same conditions, a similar but less ...
[Kristiansen, Marianne; Eriksen, Jens; Joergensen, Karl Anker Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999), 1990 , # 1 p. 101 - 103]