Deoxynucleosides and related compounds. Part VI. The synthesis of 2-thiouridine and of 3'-deoxyuridine

Abstract

2': 3'-O-isoPropylidene-O²: 5'-cyclouridine and 2': 3'-O-isopropylidene-5'-O-toluene-p-sulphonyluridine both react with sodium ethyl sulphide to give 5'-deoxy-5'-ethylthio-2':3'-O-isopropylideneuridine. The same reaction applied to O²: 2'-cyclouridine affords 3'-deoxy-3'-ethylthiouridine from which 3'-deoxyuridine is obtained by treatment with Raney nickel. 2': 3'-O-isoPropylidene-O²: 5'-cyclouridine with hydrogen sulphide and tri-ethylamine gives 2': 3'-O-isopropylidene-2-thiouridine from which 2-thiouridine can be obtained. The thiolation reaction also affords polysulphides of the probable structure R-S_2n-R where n= 1,2, or 3, and R is an iso-propylidene-2-deoxy-2-uridinyl residue.