Synthesis of C-nucleoside analogs of 2',3'-dideoxycytidine, 3'-azido-2',3'-dideoxyuridine (CS-87), and 2',3'-dideoxy-2',3'-didehydrocytidine

C-Nucleosides: Synthetic Strategies and Biological Applications

“…Procedures for modification of the carbohydrate moiety have played an important role since the discovery of C -nucleosides . Modification of the carbohydrate part of an easily accessible C -nucleoside remains the major route to compounds possessing modified (artificial) carbohydrate, such as the D4 modification in the Sartorelli preparation of D4-9-deazaguanosine (Scheme ) .…”

Azidonucleosides: Synthesis, Reactions, and Biological Properties

“…The extent to which competing O-4 alkylation occurred was found to be sensitive to steric factors, increasing in the order of MeOTf < EtOTf < pentylOTf < iPrOTf. , Several 3‘-azido-2‘,3‘-dideoxypyrimidine-like analogues have been synthesized to study their biological properties. Most of these base-modified analogues such as 3.103 , 3.104 − 3.114 , 3.115 , 3.116 and 3.117 , 3.118 and 3.119 , 3.120 , 3.121 , , 3.122 − 3.124 , 3.125 and 3.126 , 3.127 , 3.128 and 3.129 , 3.130 , 3.131 − 3.134 , 3.135 and 3.136 , 3.137 − 3.139 , and 3.140 have been synthesized using methodologies which have already been discussed during the synthesis of 1.001 (section 3.1). In each case, only the β-isomer is shown.…”

Chemistry of Nucleosides and Nucleotides

“…Whereas 332 forms in a Hilbert-Johnson-type' manner the 3-(2,3,5-tri-0-benzoyl-p-o-ribofuranosyl)pteridin-4-one (335), 333 and 334 reacted mainly at the exocyclic oxygen to provide the corresponding 4-ribosyloxy derivatives 337-339. Compound 333 yielded a complex reaction mixture which has been separated into four components by preparative TLC. This indicated the formation of an a,p-anomeric mixture of 2-dimethylamino-4-(2,3,5-tri-0-benzoyl-p-o-ribofuranosyl)pteridine (337,338) with 337 as the main product as well as two more yellow-green fluorescing, very light sensitive isomers of the alleged structures of the N-8-substituted isomeric a,p anomers 340 and 341. Treatment of 337 with HgBr2 in boiling toluene for 22 h effected some isomerization into the a anomer 338, some decomposition, but no O --+ N transglycosidation to a thermodynamically stable N-nucleoside. The ribosylation of 2-dibenzylamino-4-trimethylsilyloxypteridine (334) brought no new aspects and from the reaction mixture only the main product 2-dibenzylamino-4-(2,3,5-tri-0-benzoyl-p-o-ribofuranosyloxy)pteridine (339) has been isolated.…”

“…However, a novel improved amination procedure of ethyl 5-amino-l-(p-D-ribofuranosyl)imidazole-4-carboxylate using ammonia or primary and secondary amines and aluminum trimethyl has been described. (BI I) 5-Amino-l-(p-D-ribofuranosyl)imidazole-4-carboxamidine (337) has been prepared( 122.192) by the benzylation of adenosine l-N-oxide to produce l-N-benzyloxyadenosine hydrobromide (338) which when allowed to stand at room tempera ture for 3 days produced 5-formylamino-l-(p-D-ribofuranosyl)imidazole-4-0-benzylcarboxamidoxime (339). Nucleoside 339 was deformylated with methanolic ammonia to afford 5-amino-l-(p-D-ri bofuranosyl) imidazole-4-0-benzylcarboxamidoxime (340 the appropriate purine nucleosides in a similar manner, (192) although the first two compounds were not fully characterized.…”