Thymidine 5-deoxy-5-iodo

Selective replacement of primary hydroxyl groups in carbohydrates by iodine atoms has been achieved by using the Rydon reagent, namely, methyltriphenoxyphosphonium iodide.368 Treatment of methyl 3,4-O-isopropylidene-jS-D-galactopyranoside with the phosphonium salt in benzene for 48 hours at room temperature yielded 60% of the 6-deoxy-6-iodo derivative,369 and reaction of thymidine, uridine, and 2,2 -anhydrouridine in N,N-dimethylformamide afforded 5 -deoxy-5 -iodo derivatives in yields of 63, 65, and 31%, respectively.370... 

As a direct result of these anhydronucleoside studies, methods have been developed126,262 for the chemical synthesis of 2-deoxynucleosides of pyrimidines. It was noted126 that the 2-O-tosyluridine derivative LXXXVI, when caused to react with sodium iodide in hot 2,5-hexanedione (acetonylace-tone), is converted into a 5-0-acetyl-2-deoxy-2-iodo nucleoside which, upon reduction under alkaline conditions, yields 2-deoxyuridine (V, R = H). In analogous fashion, the 5-O-acetyl derivative of l-/S-D-ribofuranosyl-thymine68 is converted by sodium iodide to CVI which, after deacetylation followed by reduction in the presence of palladium catalyst, yields thymidine (V, R = CH,).126... 

Arylhalide 5 -iodo-2 -deoxy- uridine monophosphate Thymidine kinase Both iodine and nucleotide covalently incorporated. Only nucleotide incorporation parallels inhibition of enzyme activity (Chen et al., 1976). 

The third approach involves a short, elegant, free radical reaction of the 3 -deoxy-3 -iodo-5 -0-tritylthymidine 49 with hexamethylditin, t-butylisonitrile and azobisisobutyronitrile to give stereoselectively CNT 31. This synthetic pathway allows the stereocontrolled synthesis of CNT 31 in four steps and 22% overall yield from thymidine [79]. 

Deoxy-5 -iodo-2, 3 -0-isopropylidene-thymidine, prepared conventionally from thymidine, has been used to prepare the 5 -modified nucleosides illustrated in Scheme 1. ... 

Iodo-2 -deoxy- uridine Thymidine kinase Enhanced activity loss on photolysis thymidine protects 124... 

Verheyden and Moffatt have prepared l-(5-deoxypent-4-enofuranosyl) derivatives of uridine, thymidine, cytidine, and 2 -deoxycytidine by dehydrohalogen-ation of the acetylated 5 -deoxy-5 -iodo-nucleoside with either silver fluoride in pyridine or DBN (Scheme 89). ° Similar treatment of 3, 5 -dideoxy-3, 5 -di-iodothymidine (235) furnished the dihydrofuran derivative (236). Addition reactions of 4, 5 -unsaturated derivatives of nucleosides are mentioned in Chapter 21. 

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