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:
Aug. 08, 2006
Filed:
Dec. 13, 2002
Hirohumi Shiigi, Shunan, JP;
Noriyuki Fukada, Shunan, JP;
Kenji Tanaka, Shunan, JP;
Masao Yamaguchi, Shunan, JP;
Hirohumi Shiigi, Shunan, JP;
Noriyuki Fukada, Shunan, JP;
Kenji Tanaka, Shunan, JP;
Masao Yamaguchi, Shunan, JP;
Tokuyama Corporation, Yamaguchi, JP;
Abstract
A spirofluorenol such as 3',9′-dimethoxy-5′-hydroxyspiro[(1H-cyclopent[d,e,f]phenanthrene)-1,7′-benzo[c]fluorene] is produced by protecting a hydroxyl group bonded to a particular fluorenone compound such as 3,9-dimethoxy-5-hydroxybenzo[c]fluorene-7-one with 'a substituted silyl group in which the sum of carbon atoms of substituents bonded to a silicon atom is 5 to 12', such as a t-butyldimethylsilyl group, then, reacting the fluorenone compound with a particular organometal compound such as 1-lithiophenanthrene so as to be transformed into a spiro form and, then, removing the protection therefrom. This method makes it possible to efficiently produce the spirofluorenol which is useful as a starting material for producing photochromic compounds.