Synthesis of conformationally locked L-deoxythreosyl phosphonate nucleosides built on a bicyclo[3.1.0]hexane template.
Two conformationally locked versions of l-deoxythreosyl phosphonate nucleosides (2 and 3) were synthesized to investigate the preference of HIV reverse transcriptase for a conformation displaying either a fully diaxial or fully diequatorial disposition of substituents. Synthesis of the enantiomeric 4-(6-amino-9H-purin-9-yl)bicyclo[3.1.0]hexan-2-ol carbocyclic nucleoside precursors (diaxially disposed) proceeded straightforwardly from commercially available (1R,4S)-4-hydroxy-2-cyclopent-2-enyl-1-yl acetate employing a hydroxyl-directed Simmons-Smith cyclopropanation that culminated with a Mitsunobu coupling of the purine base. For the more complicated 1-(6-amino-9H-purin-9-yl)bicyclo[3.1.0]hexan-3-ol carbocyclic nucleoside precursors (diequatorially disposed), the obligatory linear approach required the syntheses of key 1-aminobicyclo[3.1.0.]hexan-3-yl benzoate precursors that were assembled via the amide variant of the Kulinkovich reaction involving the intramolecular cyclopropanation of a substituted δ-vinylamide. Completion of the purine ring was achieved by conventional approaches but with much improved yields through the use of a microwave reactor. The syntheses of the phosphonates and the corresponding diphosphates were achieved by conventional means. None of the diphosphates, which were supposed to act as nucleoside triphosphate mimics, could compete with dATP even when present in a 10-fold excess.
Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland 21702, United States.
Hisao
H
Saneyoshi
Jeffrey R
JR
Deschamps
Victor E
VE
Marquez
D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D008968:Molecular Conformation; D015394:Molecular Structure; D009705:Nucleosides / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D013403:Sugar Phosphates / Q000138:chemical synthesis* / Q000737:chemistry
D001643:Bridged Bicyclo Compounds; D009705:Nucleosides; D013403:Sugar Phosphates; C046059:bicyclo(3.1.0)hexane