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:
Apr. 26, 1977
Filed:
Sep. 20, 1976
Reinhard H Richter, North Haven, CT (US);
The Upjohn Company, Kalamazoo, MI (US);
Abstract
A process is described for isomerizing the cis,cis- and cis,trans-isomers of di-(p-aminocyclohexyl)methane to the corresponding trans,trans-isomer. The starting isomer, or mixture of isomers, is converted to the corresponding bis-benzaldimine by reaction with benzaldehyde (or benzaldehyde containing 1 to 3 inert substituents), the bis-benzaldimine is isomerized in the presence of a basic catalyst (potassium t-butoxide, potassium hydroxide preferred) to give predominantly the trans,trans-isomer of the bis-benzaldimine, and the latter is subjected to acid hydrolysis to yield the trans,trans-isomer of the free diamine. The process can be applied to the individual cis,cis- and cis,trans-isomers of the diamine as well as to admixtures of these isomers with the trans,trans-isomer, such as the mixtures of these stereoisomers obtained by catalytic hydrogenation of di-(p-aminophenyl)methane.