M. Krecmerova et al., SYNTHESIS OF 5-PHENYLCYTOSINE NUCLEOSIDE DERIVATIVES, Collection of Czechoslovak Chemical Communications, 61(4), 1996, pp. 645-655
Reaction of silylated 5-phenylcytosine with 1-O-acetyl-2,3,5-tri-O-ben
zoyl-D-ribose, catalyzed with tin tetrachloride, and subsequent methan
olysis afforded 5-phenylcytidine (2). This compound reacted with thion
yl chloride in acetonitrile to give cyclic sulfite 3 which on heating
in dimethylformamide was converted into hydro-1-(beta-D-arabinofuranos
yl)-5-phenylcytosine (4). Analogous reaction of compound 2 with thiony
l chloride at reflux gave 5'-chloro-5'-deoxy-2',3'-cyclic sulfite 5. I
ts heating in dimethylformamide afforded 5'-chloro-2,2'-anhydro deriva
tive 6, mild alkaline hydrolysis led to 5'-chloro-5'-deoxy-5-phenylcyt
idine (7). Alkaline hydrolysis of 5-phenyl-2,2'-anhydrocytidine (4) ga
ve 5-phenylcytosine arabinoside 8, whereas the 2,2'-anhydro derivative
6 afforded -5-deoxy-beta-D-arabinofuranosyl)-5-phenylcytosine (11). A
t higher temperature, the final reaction product was 2,5'-anhydro-5-ph
enylcytidine (12). 5'-Chloro-5'-deoxynucleosides 7 and 11 reacted with
tri-n-butylstannane to give 5'-deoxyribofuranosyl and 5'-deoxyarabino
furanosyl derivatives 15 and 16. 5-Phenylcytidine (2) was converted in
to the N-4-acetate 17 with acetic anhydride. Further reaction with ace
tic anhydride and hydrogen bromide in acetic acid afforded a mixture o
f peracetylated 2'-bromo and 3'-bromo derivatives 18 and 19. Reaction
with Zn/Cu couple gave 5'-O-acetyl-5-phenyl-2',3'-didehydro derivative
20 and 2',3',5'-tri-O-acetyl-5-phenylcytidine (21). Compound 20 was d
eblocked to ta-D-glycero-pent-2-enofuranosyl)-5-phenylcytosine (22). C
atalytic hydrogenation of compound 20 over palladium and subsequent de
blocking of the protected 2',3'-dideoxy derivative 23 gave 1-(2, xy-be
ta-D-glycero-pentofuranosyl)-5-phenylcytosine (24).