Methods of preparing 4-cyano-4 (substituted indazole) cyclohexane-carboxylic acids useful as PDE4 inhibitors
US6005118A · kind A · utility
Inventor
Key dates
| Filing date | Sep 15, 1998 |
| Grant date | Dec 21, 1999 |
| Priority date | — |
| Expiry date | Sep 15, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D231/56
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
An improved process for preparing a compound of Formula (I): ##STR1## comprising: (a) treating a compound of Formula (Ia): ##STR2## with an alcohol comprising a compound of Formula (Ib-A) and an acid comprising a compound of Formula (Ib-B): ##STR3## wherein R.sub.a is selected from the group consisting essentially of hydrogen; (C.sub.1 -C.sub.6) alkyl; phenyl and (C.sub.1 -C.sub.3) alkyl-phenyl wherein said phenyl groups are optionally substituted by one or two substituents selected from the group consisting essentially of --(C.sub.1 -C.sub.4) alkyl; --O(C.sub.1 -C.sub.3) alkyl; Br; and Cl; and PA3 HX is an acid selected from the group consisting essentially of hydrobromic acid; hydrochloric acid; sulfuric acid; sulfonic acid; and aliphatic and aromatic sulfonic acids selected from the group consisting essentially of methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, benzylsulfonic acid, p-toluene sulfonic acid, and camphorsulfonic acid, whereby HX provides the acidic conditions which result in formation of a salt of the corresponding imidate of Formula (Ic): ##STR4## and (b) hydrolyzing said compound of Formula (Ic) to provide said compound of Formula (I).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.