The general procedure for the synthesis of 4-(dimethylamino)-1,1-dimethoxy-3-buten-2-one from 1,1-dimethoxyacetone and N,N-dimethylformamide dimethyl acetal was as follows: 1,1-dimethoxy-N,N-dimethylformamide (100 g, 839 mmol, 1.02 equiv.) was mixed with 1,1-dimethoxyacetone (97 g, 821 mmol) were mixed and the reaction was stirred at 110 °C for 3 hours. The methanol generated was removed during the reaction via a Dean-Stark device. Upon completion of the reaction, the reaction solution was cooled to room temperature and the remaining volatiles were subsequently removed under vacuum to afford the crude product (E)-4-(dimethylamino)-1,1-dimethoxybut-3-en-2-one (130 g, theoretical yield 143 g, 91% yield). The product was analyzed by LC-MS, m/z 283 (M + 1). Ref: WO 2006/0097341A1 (incorporated by reference), p. 67.
