The Cyclic Dimer of 5-Fluoro-2′-Deoxyuridylic Acid: A Potent Anticancer Agent

3′‐5′ Cyclic Oligothymidylic Acids: Conformation and Complexation of Intercalating Agents

“…Two points are of interest. First, the best yield in the macrocyclization step & I , 59%; & I , 48%; &, 70%) were obtained in high dilution conditions (1)(2)(3)(4)(5) mM in pyridine) and with a large excess of coupling agent and catalyst (oligomer:l, mesitylene sulfonyl chloride:lO, tetrazole:50). Second, the cyclic oligomers were obtained almost pure (purity higher than 90%) from the crude deprotection mixture by a simple low pressure chromatography on silanized silica (Merck, item 7719).…”

(3′-5′)-Cyclic Dinucleotides: Synthetic Strategies and Biological Potential

“…c-di- 5F dUMP ( 305 ) has been entirely prepared according to the phosphotriester method as illustrated Schemes and . Cyclization and deprotection yield were 81% and 69%, respectively …”

“…These dinucleotides have been prepared by either the Hphosphonate 176−178 or the phosphoramidite 179−181 The cyclization reaction of 188 is always performed through mixed anhydride formation. Adamantoyl chloride (190), diphenylchlorophosphate (191) From 189a (XR 3 = O − ), iodine oxidation delivers in one step the corresponding base-protected cyclic dinucleotide 193a (XR 3 = YR 3 ′ = O − ) (Scheme 39). 176 Therefore, this fast access is appealing.…”

“…181 Simultaneous removal of isobutyryl and cyanoethyl groups was achieved with CH 3 NH 2 /MeOH, and finally, sugars were deprotected with Et 3 N•3HF (Scheme 40). 181 Compound 210 was cyclized using diphenylchlorophosphate (191). 177,178 122), and c-pdApdC (196) were evaluated as HIV-1 integrase inhibitors.…”

“…The resulting Hphosphonate diester was oxidized using 1-phenylsulfanylpyrrolidine-2,5-dione (194) as a sulfur transfer reagent to provide the protected linear dinucleotide 213 after removal of the levulinyl group (hydrazine hydrate). Interestingly, in this case, an N 2 ,O 6 -diprotected guanine moiety was used to increase the solubility of the linear dimer and prevent side reactions with diphenylchlorophosphate (191), subsequently used as activating agent for the cyclization step. To protect the 2′-OH function of 213, the mild acid-labile 1-(4-chlorophenyl)-4-ethoxypiperidin-4-yl (Cpep) group was selected.…”