Fused imidazo-, pyrimido- and 1,3-diazepino[1,2-c]pteridines from o-aminopyrazinecarbonitriles

Abstract

A series of partially hydrogenated imidazo[1,2-c]pteridines IXa – IXc, XIa - XIf and XVa - XVc, pyrimidol[1,2-c]pteridines XIIa - XIId and XVIa - XVIc, and 1,3-diazepinol[1,2-c]pteridines XIIIa - XIIIc and XVII have been prepared from 2-amino-3-cyanopyrazines I via reactions of I with alkanediamines II - IV and subsequent condensation of the resulting intermediates V - VII with orthoesters VIII, aldehydes X and ketones XIV.

Synthesis of N3- and 2-NH2-substituted 6,7-diphenylpterins and their use as intermediates for the preparation of oligonucleotide conjugates designed to target photooxidative damage on single-stranded DNA representing the bcr–abl chimeric gene

“…The phthalimido ring of 19 could be partially hydrolysed in high yield to the phthalic acid derivative 22 using dilute c]pteridine ring system in 27 is also rare. 37 The new compound 27 was too unstable to allow isolation of it in analytically pure form. Evidence for the proposed structure 27, however, comes from its high resolution mass spectrum, and also from its UV spectra in neutral acid and alkaline solutions, all of which correspond closely to the UV spectra reported for a closely related pteridine analog 28.…”

“…When heated in methanol solution 23 gave another unstable product, believed to be the tricyclic compound 2,3-diphenyl-5,8,9,10tetrahydropyrimido[1,2-c]pteridin-6-one 27. The pyrimido[1,2-c]pteridine ring system in 27 is also rare 37. The new compound 27 was too unstable to allow isolation of it in analytically pure form.…”