F. Seela, Kuiying Xu, Padmaja Chittepu
Jun 1, 2006
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0
Influential Citations
16
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Journal
Synthesis
Abstract
The syntheses of 7-deaza-7-fluoro-2¢-deoxyadenosine (1a), 7-deaza-7-fluoro- 2¢-deoxyinosine (3a) and 7-deaza-7-fluoro- 2¢-deoxyguanosine (3c) as well as of the 2¢-deoxy-2¢-fluoroarabino- furanosyl derivatives 1b, 3b are described. Starting materials were 6-chloro-7-fluoro-7-deazapurine (4-chloro-5-fluoropyrrolo(2,3- d)pyrimidine, 4b) and 2-pivaloylamino-6-chloro-7-fluoro-7-deaza- purine (2-pivaloylamino-4-chloro-5-fluoropyrrolo(2,3-d)pyrimi- dine, 6). Nucleobase anion glycosylation of 4b or 6 with the halogenoses 7 or 9 furnished the protected b-D-nucleosides 8, 10 and 11, which were converted to compounds 1a, 1b by ammonoly- sis and to 2a-c by sodium methoxide treatment. The 2¢-deoxy- inosine derivatives 3a, 3b and the guanosine analogue 3c were obtained from 2a-c. Conformational analysis of the nucleosides 1a, 1b was performed in solution and in the solid state. Single-crystal X-ray analyses showed that the sugar moiety of 1a exhibits the S- conformation (P = 164.8°, t = 40.1°). In solution the 2¢-fluoro sub- stituents shift the sugar conformation slightly towards N.