Thymidine 3-tosyl-5-trityl

To date, the sugar ring structure of only one desoxyribosyl nucleoside (namely, thymidine) is known. In 1935, Levene and Tipson - found that thymidine condenses with trityl chloride in the presence of dry pyridine to give a crystalline monotrityl-thymidine. From their previous proof of the structure of monotrityl-uridine as the 5-trityl ether, it seemed probable that the thymidine ether is 5-trityl-thymidine. This was confirmed by tosylation, to give tosyl-trityl-thymidine, followed by treatment with sodium iodide in acetone under standard conditions. 

Their tritylation and tosylation studies130 also indicated that the ring structure in thymidine is of the furanoid form. These aspects have been... 

There was practically no reaction with sodium iodide, indicating that the tosyl group was not situated at position (5) and that the tosylation product was 3-tosyl-6-trityl-thymidine. Hence, the ether is 5-trityl-thymidine, and thymidine can be assigned a furanose ring. This conclusion received confirmation from their observation that, unlike guanosine and inosine, thymidine does not react with boric acid and therefore does not possess two adjacent cia hydroxyl groups. 

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