US 12,454,545 B2
Method for preparing cholesterol, derivative thereof, and analog thereof
Hongxing Gan, Hunan (CN); Laibin Xie, Hunan (CN); and Xiangxin Yang, Hunan (CN)
Assigned to HUNAN KEREY PHARMACEUTICAL CO., LTD, Hunan (CN)
Appl. No. 17/617,956
Filed by HUNAN KEREY PHARMACEUTICAL CO., LTD, Hunan (CN)
PCT Filed Dec. 16, 2020, PCT No. PCT/CN2020/136678
§ 371(c)(1), (2) Date Dec. 10, 2021,
PCT Pub. No. WO2021/121239, PCT Pub. Date Jun. 24, 2021.
Claims priority of application No. PCT/CN2019/126744 (WO), filed on Dec. 19, 2019.
Prior Publication US 2022/0315620 A1, Oct. 6, 2022
Int. Cl. C07J 9/00 (2006.01)
CPC C07J 9/00 (2013.01) 7 Claims
 
1. A method for preparing a compound represented by formula III, comprising:
step (1): converting a compound represented by formula ii to a compound represented by formula a;

OG Complex Work Unit Chemistry
step (2): reducing the compound represented by formula a to a compound represented by formula b under the action of sodium borohydride, calcium chloride and pyridine;

OG Complex Work Unit Chemistry
step (3): converting the compound represented by formula b to a compound represented by formula III;

OG Complex Work Unit Chemistry
wherein,
“custom character” in formula ii, formula a, formula b, and formula III represents a single bond concurrently, or
“custom character” in formula ii, formula a, formula b, and formula III represents a double bond concurrently, or
“custom character” in formula ii represents a single bond or a double bond, and in formula a, formula b and formula III represents a double bond;
Ra and Rb are each independently selected from H, —OH, C1-3 alkyl;
PG is a hydroxy protecting group, preferably C1-8 silyl, acetyl, trifluoroacetyl, or benzoyl optionally substituted with one or more C1-8 alkyl;
R is L1-R1;
L1 is null, or C1-8 alkylene;
LG is a leaving group;
R1 is selected from H, C1-8 alkyl, C1-8 alkenyl, —OH, —O(C1-8 alkyl), —O-PG1, —C(═O)O(C1-8 alkyl), —C(═O)N(C1-8 alkyl)2, wherein the alkyl or alkenyl is optionally substituted with 1, 2 or 3 groups selected from —OH, —O(C1-8 alkyl), —O-PG1, —C(═O)O(C1-8 alkyl) and —C(═O)N(C1-8 alkyl)2;
PG1 is a hydroxyl protecting group, preferably selected from C1-8 silyl or a C1-6 alkoxy substituted methyl group.