867065-53-0

General procedure for the synthesis of ethyl 2-(4-(tert-butoxycarbonyl)piperazin-1-yl)thiazole-4-carboxylate from ethyl 2-bromothiazole-4-carboxylate and N-BOC-piperazine: ethyl N-BOC-piperazine (1.8 g, 10 mmol), ethyl 2-bromothiazole-4-carboxylate (2.36 g, 10 mmol) and N,N-diisopropylethylamine (DIPEA. 2.02 g, 20 mmol) were dissolved in 1,4-dioxane (15 mL). The reaction mixture was stirred at 100°C overnight. Upon completion of the reaction, it was extracted with ethyl acetate (EA) and the organic phase was washed with saturated saline. Purification by fast column chromatography (eluent: petroleum ether/ethyl acetate = 5:1 to 3:1) afforded a yellow solid product (3.0 g, 88% yield).

[1] Patent: US2018/141923, 2018, A1. Location in patent: Paragraph 0599; 0600; 0601
[2] Patent: WO2008/83238, 2008, A2. Location in patent: Page/Page column 112
[3] Patent: WO2018/26890, 2018, A1. Location in patent: Paragraph 0479; 0480