PURPOSE: To obtain the subject compound by condensing a 5-substituted pyrimidine derivative with a 3-organothio-2,3-dideoxy-pentofuranose derivative in the presence of a Lewis acid, thereby efficiently obtaining the 2β-isomer in good yield and selectivity, and further carrying out oxidation, thermal decomposition and deprotection.
CONSTITUTION: A 5-substituted pyrimidine derivative expressed by formula I (R1 to R3 are alkyl or phenyl; X is 0 or N; Y is H, halogen, alkyl or alkenyl) and a 2,3-dideoxy-3-(organothio)pentofuranose derivative expressed by formula II (R4 is protecting group of OH; R5 is alkyl, phenyl, etc.; Z is halogen, acyloxy, etc.) are subjected to condensing reaction to provide a 1-(2,3-dideoxy-3- organothio-β-D-pentofuranosyl)pyrimidine derivative expressed by formula III. The resultant derivative is then oxidized with a peroxide to afford a compound expressed by formula IV, which is subsequently heated in the presence of a base to provide a compound expressed by formula V. The obtained compound expressed by formula V is finally subjected to deprotecting reaction to afford the objective 2',3'-dideoxy-2',3'-didehydro-β-ribonucleoside derivative expressed by formula VI.
KOSEKI YUKIFUMI
EBATA TAKASHI
MATSUSHITA HAJIME
NAOI YOSHITAKA
ITO KAZUO
YUKI GOSEI YAKUHIN KOGYO KK