L- cytosine

Another example relates to OH -aided one-electron oxidation of cytosine. With cytosine, the OH reaction proceeds by addition to C(5), a process that has a selectivity of 90% [24]. The 5-hydroxy-6-yl radical is an excellent reductant, and the same is true for the ionized 6-yl radical formed by deprotonation from N(l). This radical anion now contaim sufficient electron density to eliminate the OH group at C(5) as OH". The result is the cytosine-l-yl radical which is oxidizing, probably due to appreciable spin density at the hetero atoms N(l) and... 

Regioselective ring-cleavage of cyclic derivatives of carbohydrates is a useful method for achieving their selective deprotection. 3, 5 -0-(Tetraisopropyldisiloxane-l,3-diyl) derivatives of nucleosides (51, B = uracil-1-yl, cytosin-l-yl, N4-benzoylcytosin-l-yl, guanin-9-yl, or adenin-9-yl) have been prepared,317 and selectively cleaved in 95% yield at the silicon-0-3 bond on treatment with 0.2 M sodium hy-... 

Cis- and trans-isomers of 2-hydroxymethyl-5-(cytosin-l -yl)-l,3-oxathiolane was obtained by action of methanolic ammonia at 24°C. 

Deoxy-4-thiopentofuranosyl)cytosine OL-L-erythro -form, D-376 1 -(2-Deoxy-4-thiopentofuranosyl)cytosine -L-erythro -form, D-376 l-(2-Deoxy-4-thiopentofuranosyl)cytosine ci-L-threo-form, D-376 1 -(2-Deoxy-4-thiopentofuranosyl)thymine -D-erythro -form 5 -Ac,... 

B = cytosin-l-yl, adenin-9-yl, guanin-9-yl, etc. Reagents i, ROPOsHa-DCC-DMF ii, AcOH-py (high dilution)... 

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