Azines and azoles: CXXVII. Glycosylation of 5,7-dihydro-4 H -pyrano-[2,3- d :6,5- d′ ]dipyrimidine-4,6(3 H )-dione and its 5-phenyl-substituted analog

Glycosylation of 5-phenylpyrano[2,3-d:6,5-d′]dipyrimidine-4,6-diones through the corresponding di-O-trimethylsilyl derivative with excess 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose gives a mixture of 3-mono-and 3,7-bis(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-5-phenylpyrano[2,3-d:6,5-d′]dipyrimidines; in the reaction with equimolar amounts of the reactants, only the monoriboside is formed. Isomeric N,N′-disubstituted pyranodipyrimidines, as well as mixtures of their mono-and disubstituted derivatives can be separated by fractional crystallization. The alkylation of pyrano[2,3-d:6,5-d′]dipyrimidine-4,6-dione and its 5-phenyl-substituted derivative with 2-oxabutane-1,4-diyl diacetate provides an efficient procedure for the synthesis of acyclic analogs of glycosides based on pyrano[2,3-d:6,5-d′]dipyrimidines. Original Russian Text ? E.V. Fedorova, V.V. Kvasha, E.P. Studentsov, A.V. Moskvin, B.A. Ivin, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 4, pp. 630–636. For communication CXXVI, see [1].