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:
Dec. 02, 1997
Filed:
Apr. 08, 1994
Tokuyama Corporation, Tokuyama, JP;
Abstract
Spiropyrone compounds represented by the general formula ##STR1## wherein ##STR2## is a substituted or an unsubstituted aromatic hydrocarbon group or a substituted or an unsubstituted unsaturated heterocyclic group, and ##STR3## is a substituted or an unsubstituted 2-bicyclo�3,3,1!9-nonenylidene group, that are starting materials of spiropyran compounds which change from a colorless state into a colored or a densely colored state upon irradiation with the light containing ultraviolet rays such as the sunlight or the light of a mercury lamp, the change being reversible, and a process for preparing the spiropyrone compounds. The process comprises reacting a compound represented by the general formula ##STR4## wherein ##STR5## is as defined above, with a compound of the general formula ##STR6## wherein ##STR7## is as defined above.