1,7‐Dideaza‐2′,3′‐dideoxyadenosine: Syntheses of Pyrrolo[2,3‐b]pyndine 2′,3′‐Dideoxyribofuranosides and Participation of Purine N(1) during HIV‐1 Reverse Transcriptase Inhibition

Abstract

The syntheses of 1,7-dideaza-2',3'-dideoxyadenosine (1) and related pyrrolo [2,3-b]pyridine 2',3'-dideoxyriboand 2',3'-didehydro-2',3'-dideoxyribonucleosides (see 2-5) are described. As starting materials, 2'-deoxyribonucleosides 6 or 7 were used. The 3'-OH group was removed by Burton deoxygenation or via mesylation followed by elimination and catalytic hydrogenation. Compound 1 was also obtained from the direct glycosylation of 4-nitro-lH-pyrrolo[2,3-b]pyridine (17) with the 2,3-dideoxyribofuranosyl chloride 18. The triphosphate 25 of 1 showed only marginal activity against HIV-1 reverse transcriptase, indicating that purine N(l) is required for the inhibitory activity of the parent 2',3'-dideoxyadenosine.

A New Process for Antineoplastic Agent Clofarabine

“…Sodium hydride gave only a modest preference for the beta anomer 5 ( 5 / 6 = 1.3), whereas the amidine and guanidine bases (DBU and N , N , N ‘, N ‘-tetramethylguanidine (TMG)) afforded the alpha anomer 6 in preference to 5 (entries 1−3, Table ) 2c. Potassium carbonate gave an anomeric ratio similar to sodium hydride ( 5 / 6 = 1.2), while cesium carbonate 10b gave a slightly improved ratio (2) and higher overall conversion (70%) (entries 4−5, Table ). A marked increase in the conversion was observed with sodium tert -butoxide (89%), although the anomeric ratio remained similar to sodium hydride (1.3).…”

Isomerism of Bis(7-azaindolyl)methane

“…Compound 2 , on the other hand, has a 1-N - bound 7-azaindolyl (7-azaindol-1-yl) group and a 7-N-bound 7-azaindoly (7-azaindol-7-yl) group, i.e., it contains both the normal form and the tautomer form of 7-azaindolyl. The N-alkylation of nitrogen-heterocycles (such as pyrazoles, pyrroles, imidazoles, and indoles) by means of a phase-transfer technique is a well-established and very convenient method for preparing the corresponding N-alkyl derivatives . 7-Azaindole is known to have multiple active sites toward electrophilic substitution 3a.…”

1,7‐Dideaza‐2′‐deoxyadenosine: Building blocks for solid‐phase synthesis and secondary structure of base‐modified oligodeoxyribonucleotides

“…-Recently, 1,7-dideaza-2'-deoxyadenosine (1) was synthesized in our laboratory in a stereochemically controlled reaction [7]. The 2',3'-dideoxyribonucleoside was also prepared [8]. The ribonucleoside was described earlier by others [9].…”