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:
Nov. 24, 1981
Filed:
Jan. 31, 1980
Applicant:
Inventors:
Gert Nagl, Frankfurt am Main, DE;
Joachim Ribka, Offenbach-Burgel, DE;
Ulrich Gotsmann, Frankfurt am Main, DE;
Heinz Dickmanns, Frankfurt am Main, DE;
Assignee:
Cassella Aktiengesellschaft, Frankfurt, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C07D / ;
U.S. Cl.
CPC ...
544 37 ;
Abstract
An improved process for preparation of a condensed product of phenothiazine and p-nitrosophenol which contains more than 60% by weight of indophenol S-oxide of the formula ##STR1## by condensing phenothiazine with p-nitrosophenol in sulphuric acid wherein the improvement comprises the phenothiazine being in 60 to 90% strength sulphuric acid at the time of addition of the p-nitrosophenol.