描述：底物如图，11到12
1,8-Dibromo-3,6,9,9-tetramethyl-9,10-dihydroacridine(790 mg, 2 mmol) and Et2O (25 mL) were added to a flamed dried three necked flask equipped with a dropping funnel containing n-BuLi (8.8 mmoL). The mixture was cooled to –40 oC and the n-BuLi was added dropwise. The mixture became clear and turned yellow. After the additon, the mixture was stirred at room temperature for 3 h. Then the solution was cooled to –40 oC again and dry CO2 was bulbed into the solution for 1 h. The mixtrue was treated with 2 N HCl (aq), and the solid was collected through filtration. After being washed with petroleum ether, the desired product was obtained as yellow solid (511 mg, 79% yield).
按照文献做，加完丁基锂是黄色，搅拌时间2个小时左右，无论是低温（-40或者-78）还是常温，或者0度，时间长了体系就变黑了，不知道是不是坏了
用THF做溶剂的话，-78下，加完丁基锂立刻变黑
现在就干脆低温-78下，乙醚溶剂，加完丁基锂后低温保持1小时，加干冰，然后加酸后处理，萃取，原料是没了，但是感觉没什么产物
求指点，丁基锂-78一个小时够不够拔溴，还有什么要注意的吗
溶剂都是现蒸，肯定无水
有一篇类似文献是这样的，加TMSCl，不知道是不是为了保护NH，不知道我那个NH是不是要保护，而一样底物也就只有那一篇文献
求高手指点！
