Uridine, monotrityl

Tipson devoted most of his years in Levene s laboratory accomplishing seminal work on the components of nucleic acids. To determine the ring forms of the ribose component of the ribonucleosides he applied Haworth s methylation technique and established the furanoid structure for the sugar in adenosine, guanosine, uridine, and thymidine. He showed that formation of a monotrityl ether is not a reliable proof for the presence of a primary alcohol group in a nucleoside, whereas a tosyl ester that is readily displaced by iodide affords clear evidence that the ester is at the 5-position of the pentofuranose. Acetonation of ribonucleosides was shown to give the 2, 3 -C -isopropyl-idene derivatives, which were to become extensively used in nucleoside and nucleotide chemistry, and were utilized by Tipson in the first chemical preparation of a ribonucleotide, inosinic acid. 

This formulation has been confirmed by a study of trityl-uridine, a substance first isolated (in a highly impure state) by Bredereck" in 1932 and assumed by him, without direct experimental evidence, to be 6-trityl-uridine. Levene and Tipson - succeeded in separating the crude material into two crystalline substances, one a monotrityl- and the other a ditrityl-uridine. Furthermore they found that treatment of the monotrityl-uridine with trityl chloride gives the ditrityl derivative. The structure of the monotrityl-uridine was determined as follows. On... 

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. 

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