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:
Jun. 10, 1997
Filed:
Sep. 27, 1995
Puthalath K Sujeeth, Maryland Heights, MO (US);
Warner-Jenkinson Company, Inc., St. Louis, MO (US);
Abstract
A process for the manufacture of fluorescein compounds suitable for conversion to FDA certified dyes is described. The fluorescein compounds, and in particular fluorescein (also known as Solvent Yellow 94 or D&C Yellow No.7) and 3,4,5,6-tetrachlorofluorescein, are made by a process involving the condensation of a phthalic anhydride with several molar excess of a resorcinol, the resorcinol being employed not only as a reactant, but also as a solvent for the reaction. This process also can employ the unreacted resorcinol and any intermediates or by-products from the condensation reaction as a reactant and as a solvent in subsequent condensation reactions.