1. Academic Validation
  2. Synthesis of 4'-Ethynyl-2'-deoxy-4'-thioribonucleosides and Discovery of a Highly Potent and Less Toxic NRTI

Synthesis of 4'-Ethynyl-2'-deoxy-4'-thioribonucleosides and Discovery of a Highly Potent and Less Toxic NRTI

  • ACS Med Chem Lett. 2011 Sep 8;2(9):692-697. doi: 10.1021/ml2001054.
Kazuhiro Haraguchi 1 Hisashi Shimada Keiogo Kimura Genta Akutsu Hiromichi Tanaka Hiroshi Abe Takayuki Hamasaki Masanori Baba Elizabeth A Gullen Ginger E Dutschman Yung-Chi Cheng Jan Balzarini
Affiliations

Affiliation

  • 1 School of Pharmacy, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
Abstract

The synthesis of 4'-ethynyl-2'-deoxy-4'-thioribonucleosides was carried out utilizing an electrophilic glycosidation in which 4-ethynyl-4-thiofuranoid glycal 16 served as a glycosyl donor. Electrophilic glycosidation between 16 and the silylated nucleobases (N4-acetylcytosine, N6-benzoyladenine and N2-acetyl-O6-diphenylcarbamoylguanine) was carried out in the presence of N-iodosuccinimide (NIS) leading to the exclusive formation of the desired β-anomers 29, 33 and 36. Anti-HIV studies demonstrated that these 4'-thio nucleosides were less cytotoxic to T-lymphocyte (i.e. MT-4 cells) than the corresponding 4'-ethynyl derivatives of 2'-deoxycytidine (44), 2'-deoxyadenosine (45) and 2'-deoxyguanosine (46). Comparison of the selectivity indices (SI) was made between 4'-thionucleosides (32, 41 and 43) and the corresponding 4'-oxygen analogues 44-46 by using the reported CC50 and EC50 values. In the case of cytosine and adenine nucleosides, comparable SI values were obtained: 32 (545) and 45 (458); 41 (>230) and 45 (1,630). In contrast, 4'-ethynyl-2'-deoxy-4'-thioguanosine 43 was found to possess a SI value of >18,200, which is twenty times better than that of 46 (933).

Keywords

4’-thionucleosides; anti-HIV-1 activity; electrophilic glycosidation; glycal; nucleoside reverse transcriptase inhibitors.

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