Solventless protocol for efficient bis-N-boc protection of adenosine, cytidine, and guanosine derivatives.
A solvent-free reaction employing a simple low-energy ball mill apparatus converts the amino groups of adenosine, 2-deoxyadenosine, cytidine, 2-deoxycytidine, guanosine, and 2-deoxyguanosine as well as some of their ribosyl O-protected derivatives to the corresponding bis-N-Boc carbamates. In the case of guanosine compounds, the carbonyl group of the base moiety was also blocked as its O-Boc enol carbonate. A variation of this approach using transient in situ O-silylation permitted the preparation of bis-N-Boc nucleosides in which the sugar hydroxyls were unprotected. The ball mill reactions were rapid, convenient, and very high-yielding except in the case of the guanosine compounds. This highly efficient method protects the amino groups of these nucleosides with a base stable and acid labile group suitable for further synthetic manipulation.
Sikchi
Siddharth A
SA
Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.
Hultin
Philip G
PG
D000241:Adenosine / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D002241:Carbohydrates / Q000737:chemistry; D003562:Cytidine / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D006151:Guanosine / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D006900:Hydroxylation; D015394:Molecular Structure; D012997:Solvents
D002241:Carbohydrates; D012997:Solvents; D006151:Guanosine; D003562:Cytidine; D000241:Adenosine