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. 12, 1978
Filed:
Sep. 14, 1977
Applicant:
Inventors:
Alfred Maierhofer, Allensbach, DE;
Hans Wagner, Kostanz, DE;
Assignee:
Deutsche Gold- und Silber-Scheideanstalt vormals Roessler, Frankfurt, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
562557 ; 560153 ;
Abstract
Very pure S-carboxymethyl-L-cysteine is prepared by reacting L-cystine in liquid ammonia with metallic sodium to form the disodium salt of L-cysteine, evaporating the ammonia, reacting the disodium salt of L-cysteine with an aqueous solution of chloroacetic acid and precipitating the S-carboxymethyl-L-cysteine formed by acidifying the reaction mixture. There is employed 0.1 to 10 weight percent of a reducing agent based on the chloroacetic acid.