Process for the preparation of 1,1-dichloroalkenes

US4342704A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Hellmut Hoffmann
• Fritz Maurer · Wuppertal, DE
• Uwe Priesnitz · Solingen, DE
• Hans-Jochem Riebel · Bad Camberg, DE

Key dates

• Filing date: Jul 2, 1980
• Grant date: Aug 3, 1982
• Expiry date: Jul 2, 2000

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07F9/42
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for the preparation of a 1,1-dichloroalkene of the formula ##STR1## in which R.sup.1 is hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, aralkyl or aryl radical, and PA1 R.sup.2 is an optionally substituted alkyl, alkenyl, alkynyl, aralkyl, aralkenyl or aryl radical, or cycloalkyl which is optionally substituted by halogen, alkyl, alkanoyl, carbamoyl, cyano or phenyl, or PA1 R.sup.1 and R.sup.2 together form a hydrocarbon chain which is optionally branched and/or optionally contains a fused benzene ring, comprising reacting an aldehyde or ketone of the formula ##STR2## with a dichloromethane-phosphonic acid ester of the formula ##STR3## in which R.sup.3 each independently is alkyl or phenyl or the two radicals R.sup.3 together are alkanediyl, in the presence of a base at a temperature between about -50.degree. and +50.degree. C. Preferably either the base is metered into a mixture of the aldehyde or ketone and phosphonic acid ester or the ester is added to a mixture of the base and aldehyde or ketone.