申请人:——
公开号:US20040068107A1
公开(公告)日:2004-04-08
The present invention relates to an improved process for the preparation of pentopyranosyl nucleosides, in which a significant improvement and simplification of the process step described in DE-A-19741715 can be achieved. Using the process according to invention, a migration of the 2′-acyl protective group from the 2′-position to the 3′-position of the pentopyranoside is brought about, a catalyst of the formula IVa or IVb being used
1
In this formula, A is —CH
2
— or —NR
20
—, R
20
is hydrogen, alkyl, cycloalkyl, aryl, aralkyl, each of which is optionally substituted, D is a group of the formula —C
m
H
2m
—, and
m is an integer from 1 to 6, R
18
, R
19
and R
24
independently of one another, identically or differently, are hydrogen, alkyl, cycloalkyl, aryl or aralkyl, each of which is optionally substituted, or R
18
and R
19
are together a group —C
o
H
20
—, where o is an integer from 2 to 4, and R
21
is a group —NR
22
R
23
, in which R
22
and R
23
independently of one another, identically or differently, are hydrogen, alkyl, cycloalkyl, aryl or aralkyl, each of which is optionally substituted.
本发明涉及一种制备五吡喃糖基核苷的改进工艺,其中可以实现 DE-A-19741715 中所述工艺步骤的显著改进和简化。采用本发明的工艺,可以使戊吡喃糖苷的 2′-酰基保护基从 2′-位迁移到 3′-位,使用的催化剂为式 IVa 或 IVb
1
式中,A 是 -CH
2
- 或-NR
20
-, R
20
是氢、烷基、环烷基、芳基、芳烷基,其中每个基团都被任选取代,D 是式 -C
m
H
2m
-和
m 是 1 到 6 的整数,R
18
, R
19
和 R
24
是氢、烷基、环烷基、芳基或芳烷基,其中每个都被任选取代,或 R
18
和 R
19
共同为基团 -C
o
H
20
-,其中 o 是 2 至 4 的整数,R
21
是基团 -NR
22
R
23
,其中 R
22
和 R
23
是氢、烷基、环烷基、芳基或芳烷基,其中每一个都被任选取代。