G. García-Muñoz

Heterocyclic N-glycosides—V : Synthesis of unsaturated N-glycosides from 6-chloropurine and derivatives of d-xylal and l-arabinal. A conformational NMR study

Abstract The acid-catalyzed reaction of 6-chloropurine with 3,4-di-O-acetyl- d -xylal yielded four compounds. The main products were shown to be the corresponding 6-chloro-9-(4′-O-acetyl-2′,3′-dideoxy-α and β- d -glycero-pent-2′-enosyl)purine, and 1,2,3-trideoxy-4-O-acetyl-3-(6′-chloro-9′-purinyl) d -threo- pent-1-enopyranose. On the other hand reaction of 6-chloropurine with 3,4-di-O-acetyl- l -arabinal yielded, in addition to the enantiomers of the above compounds, 6-chloro-9-(3′,4′-di-O-acetyl-2′-deoxy- α- and β- l -erythro-pentopyranosyl)purine. A NMR study of these compounds showed that the previous reported assignations for 6-chloro-9-(3′,4′-di-O-acetyl-2′-deoxy-α- and β- d -erythro-pentopyranosyl) purine are in error. The conformations of all compounds obtained, as determined from their NMR parameters, are discussed.

Heterocyclic N-glycosyl derivatives—XI: Synthesis and NMR conformational study of N-glycosyl benzotriazoles from acetylated glycals

Abstract Acid-catalyzed reaction of benzotriazole, 5,6-dimethylbenzotriazole and 5,6-dichlorobenzotriazole with di-O-acetyl- d -xylal in ethyl acetate afforded 1-(4′-O-acetyl-2′,3′-dideoxy- d - glycero -pent-2′-enopyranosyl)benzotriazole derivatives and small amounts of 1,2,3-trideoxy-4-O-acetyl-3-(benzotriazolyl)- d - threo -pent-1-enopyranose derivatives. The reactions using di-O-acetyl- l -arabinal led to the formation of the corresponding 1- and 2-(3′,4′-di-O-acetyl-2′-deoxy- l - erythro -pentopyranosyl)benzotriazole derivatives. In addition the enantiomers of the above 2′, 3′-unsaturated N-glycosyl compounds were also obtained. The configurations and conformations of the products obtained were determined by NMR spectroscopy.