1998 multi-membered N-heterocycles

multi-membered N-heterocyclesR 0690

48 - 170A Novel Fused Heterocyclic System – Synthesis of Substituted 9,10-Dihydro-1,3,4,6,7,10-hexaazacyclohepta[de]naphthalen-8(7H)-ones.— The chlorine substituted pyrimido[4,5-d]pyrimidine (III), synthesized fromthe pyrimidine (I), is converted into a series of new pyrimido[4,5-d]pyrimidines(V) by reaction with α-aminoacidic esters (IV). These esters undergo in-tramolecular ring closure in refluxing EtOH to furnish the title compounds(VI), which are representatives of a novel tricyclic heterocyclic ring sys-tem. — (WANG, Z.; NEIDLEIN, R.; Tetrahedron 54 (1998) 33, 9903-9910;Pharm.-Chem. Inst., Ruprecht-Karls-Univ., D-69120 Heidelberg, Germany; EN)

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