| abstract |
In our research, two commercially available compounds, 3-amino-1,2,4-dithiazole-5-thione (1) and xanthane hydride (2), and their derivatives 3-6 are found to be potential sulfur-transfer reagents. The efficiency and optimization of these new sulfur-transfer reagents were investigated by solid-phase synthesis of dinucleotide and oligonucleotide phosphorothioates. The results show that both compounds (1) and (2) are highly efficiency sulfurizing reagents, and better than 99 % sulfur transfer efficiency can be achieved at each step. In contrast to Beaucage reagent, these novel sulfur-transfer reagents are very stable in various solvents, and are available in bulk quantities at low cost. Due to these advantages, compounds (1) and (2) can be considered alternatives to Beaucage reagent, especially in large-scale preparation of oligonucleotide phosphorothioates. Furthermore, compounds (1) and (2) were modified to enhance their solubility in acetonitrile. Three types of structure, as described as Formulae (I), (II) and (III), are considered as potential efficient sulfur-transfer reagents based on our results. |