[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8](=[O:10])[CH3:9].CO[CH:13](OC)[N:14]([CH3:16])[CH3:15].C(#N)C>C1(C)C=CC=CC=1>[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8](=[O:10])[CH:9]=[CH:13][N:14]([CH3:16])[CH3:15]To a 5 liter, 3-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser capped with a nitrogen inlet, and a heating mantle were added o-chloroacetophenone (305.8 g), N,N-dimethylformamide dimethyl acetal (707.0 g), and acetonitrile (dried over molecular sieves, 3.0 L) giving an orange solution. The mixture was heated gradually to reflux (83° C.) over 1.5 hours, then maintained at reflux for 18 hours. After the dark red solution was cooled to room temperature, the acetonitrile was evaporated, leaving a heavy red oil. The oil was redissolved in toluene (1L). The toluene was evaporated to afford the crude enamine which was further dried under high vacuum overnight to afford 2'-chloro-3-dimethylaminopropenophenone (422 g) which was used without further purification.
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