The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 06, 2003
Filed:
Sep. 05, 2002
Jeong-Kyu Kim, Daejeon-shi, KR;
Chul-Hwan Choi, Daejeon-shi, KR;
LG Chem, Ltd., Seoul, KR;
Abstract
This invention provides a method for preparing 2-(2-hydroxyphenyl)-2H-benzotriatzole of formula (I) below, consisting of steps of: a) performing a first reduction in which hydrazine hydrate is added to a compound of formula (II) below with or without a phase transition catalyst in the presence of solvents which include a nonpolar solvent, water, and an alkaline compound, thereby preparing a compound of formula (III) below; and b) performing a second reduction in which water is added to the compound of formula (III) prepared in step a), and then zinc powder and sulfuric acid are added thereto with or without the phase transition catalyst, wherein, X is halogen or hydrogen; R is hydrogen, C -C alkyl, C -C cycloalkyl, phenyl, or phelyl-C -C alkyl; and R′ is C -C alkyl, C -C cycloalkyl, phenyl, or phenyl-C1-C4 alkyl.