1,3-Dimethylbarbituric Acid

Abstract

[769-42-6] C6H8N2O3 (MW 156.13932) InChI = 1S/C6H8N2O3/c1-7-4(9)3-5(10)8(2)6(7)11/h3H2,1-2H3 InChIKey = VVSASNKOFCZVES-UHFFFAOYSA-N (active methylene reagent useful for condensation reactions, for preparing synthetic intermediates, particularly heterocycles; widely used in multicomponent reactions during recent years, leading rapidly to various libraries of biologically active molecules) Alternate Names: 1,3-dimethyl-2,4,6(1H,3H,5H)-pyrimidinetrione; 1,3-dimethylbarbituric acid; N,N′-dimethylbarbituric acid; 1,3-dimethyl-1,3-diazinane-2,4,6-trione. Physical Data: mp 121–123 °C; pKa = 4.68.1 Solubility: soluble in water, 60 g/L−1 (20 °C). Form Supplied in: white crystalline powder, commercially available. Analysis of Reagent Purity: 1H NMR, HPLC. Preparative Method: syntheses of 1,3-dimethylbarbituric acid were reported in 19212 and 1941.3 However, the syntheses involved several steps,3 and scaling up led to undesired products. Later, a more efficient, scalable procedure was reported using 1,3-dimethylurea, malonic acid, and acetic anhydride in acetic acid.4 Handling, Storage, and Precautions: the reagent must be stored in a cool, dry place in a tightly closed container. Any contact with eyes (risk of serious permanent damage), skin (harmful irritant), or clothes must be avoided. Appropriate protective eyeglasses or chemical safety goggles and gloves are required.