476331-76-7Relevant articles and documents
S-pixyl analogues as photocleavable protecting groups for nucleosides
Coleman, Michael P.,Boyd, Mary K.
, p. 7641 - 7648 (2007/10/03)
Several analogues of the 9-phenylthioxanthyl (S-pixyl) photocleavable protecting group have been synthesized, containing substituents on the 9-aryl ring and on the thioxanthyl backbone. Each analogue protected the 5′-hydroxy moiety of thymidine in good to excellent yield. The protected substrates were deprotected in 1:1 water: acetonitrile with irradiation at 300 nm, resulting in recovered thymidine in excellent yield, except for the nitro-substituted analogues which gave substantially lower yields. Substrates with 2,7-dibromo or 3-methoxy substitution on the thioxanthyl backbone were also deprotected efficiently with irradiation at 350 nm. Shorter irradiation times were observed in the less nucleophilic solvent mixture of 1:9 trifluoroethanol: acetonitrile, with no formation of secondary photooxidation products. Photodeprotection with high yields was also achieved in the absence of solvent, with no secondary photoproducts.
