New Boron-Nitrogen Analogues of Uracil Derivatives

Abstract : The reaction of N,N'-dimethylurea with 1,5-dimethyl-2,4-bis- (dimethylamino)-1,5-diaza-2,4-dibora-3-oxacyclohexan-6-one (2) in the melt proceeds with condensation of the urea to yield two major products: the acid 1, 3,5-trimethyl-2-hydroxy-1,3,5-triaza-2-boracyclohexa-4,5-dione (1a); and a mixture of the niethylammonium (4a) and dimethylammonium (4b) of the anion CH3Nmu-CONCH3)2 2B. Analogous product were obtained from the reaction of 2 with N,N', N -triorganylbiurets. The 2-hydroxy derivatives of type 1 form 1:1 molar adducts with amines (3) of variable thermal stability. The anhydride of 1a was obtained as the bis(dimethylamine) adduct CH3Nmu- CONCH3)2B2O.2(CH3)2NH (6) from the reaction of (CH3)2N2BOBN(CH3)22 with N,N',N -trimethylbiuret. Keywords: Azaborauracils, isoelectronic species.