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在氮氣保護下,將1-(6-硝基吡啶-3-基)哌嗪(15.6 g,0.075 mol)懸浮于120 mL四氫呋喃(THF)中。依次加入三乙胺(10.5 mL,0.075 mol)和4-二甲基氨基吡啶(0.46 g,5 mol%)至懸浮液中。將二碳酸二叔丁酯(16.6 g,0.075 mol)溶解于50 mL THF中,轉(zhuǎn)移至滴液漏斗中。緩慢滴加該溶液至攪拌的懸浮液中,控制滴加速度使反應(yīng)溫度維持在27°C以下。滴加完畢后,將反應(yīng)混合物冷卻至室溫,隨后加熱至回流?;亓鞣磻?yīng)1小時后,過濾除去少量不溶物。減壓濃縮除去溶劑,將黃色殘余物在乙酸乙酯(EtOAc)和水之間分配。水相用EtOAc萃取兩次。合并有機層,依次用少量水和飽和氯化鈉溶液洗滌,干燥后減壓濃縮。所得固體通過2-丙醇(經(jīng)活性炭處理)重結(jié)晶,得到目標產(chǎn)物4-(6-硝基-3-吡啶基)-1-哌嗪甲酸叔丁酯,約19 g(產(chǎn)率約80%)。核磁共振氫譜(1H NMR,CDCl3)δ: 1.49(s,9H),3.46(m,4H),3.65(m,4H),7.20(m,1H),8.17(m,2H)。質(zhì)譜(m/z): 309。
參考文獻:
[1] Patent: WO2006/95159, 2006, A1. Location in patent: Page/Page column 77-78
[2] British Journal of Pharmacology, 2018, vol. 175, # 12, p. 2399 - 2413
[3] Journal of Medicinal Chemistry, 2005, vol. 48, # 7, p. 2388 - 2406
[4] Patent: WO2006/8545, 2006, A2. Location in patent: Page/Page column 153
[5] Journal of Medicinal Chemistry, 2010, vol. 53, # 22, p. 7938 - 7957