Patent ID: 8314242

Claim:
A process for preparation of a 4-aminobut-2-enolide of formula (I) comprising reacting a 4-(methylamino)furan-2(5H)-one of formula (II) with an amine of formula (III) optionally in the presence of a Brønstedt acid to form a compound of the formula (I), wherein: R 1 represents hydrogen, C 1-12 -alkyl, C 1-12 -haloalkyl, C 2-12 -alkenyl, C 2-12 -haloalkenyl, C 2-6 -alkynyl, C 3-8 -cycloalkyl, C 3-8 -cycloalkyl-C 1-6 -alkyl, C 3-8 -halocycloalkyl, C 1-12 -alkoxy, C 1-6 -alkoxy-C 1-6 -alkyl, C 3-8 -halocycloalkyl-C 1-6 -alkyl or aryl-C 1-6 -alkyl; R 2 represents C 1-12 -alkyl, aryl or aryl-C 1-6 -alkyl; and A represents pyrid-2-yl, pyrid-4-yl or pyrid-3-yl, which is optionally substituted in the 6-position by F, Cl, Br, CH 3 , CF 3 , or OCF 3 , or represents pyridazin-3-yl which is optionally substituted in the 6-position by Cl or CH 3 , or represents pyrazin-3-yl, or 2-chloropyrazin-5-yl, or represents 1,3-thiazol-5-yl optionally substituted in the 2-position by Cl or CH 3 , or represents pyrimidinyl, pyrazolyl, thiophenyl, oxazolyl, isoxazolyl, 1,2,4-oxadiazolyl, isothiazolyl, 1,2,4-triazolyl or 1,2,5-thiadiazolyl, which is optionally substituted by F, Cl, Br, CN, NO 2 , C 1-4 -alkyl, C 1-3 -alkylthio or C 1-3 -alkylsulphonyl, where each of the radicals C 1-4 -alkyl, C 1-3 -alkylthio and C 1-3 -alkylsulphonyl may be substituted by F, chlorine, or a combination thereof or represents a substituted heterocyclyl of the following formula in which: X represents halogen, C 1-12 -alkyl or C 1-12 -haloalkyl, and Y represents halogen, C 1-12 -alkyl, C 1-12 -haloalkyl, C 1-12 -haloalkoxy, azido or CN.