问题：奇怪，这个反应的机理是什么？
类型：求助 (悬赏分:3分)
提问：quan
等级：▲▲
版块：有机化学问题(jimuwei,fpcwin1211,netpanda,yjgzfl,Ftian,)
信誉：82%
回复：7
阅读：591
时间：2005-08-12 09:57:55 编辑加入/取消收藏订制/取消短消息举报该贴

是一篇专利上的，没有看懂。同志们参详参详
A solution of 5 mL (49mMol) 4-methoxypyridine in 200 mL tetrahydrofuran was cooledto-40 C, and then 6.9 mL (55mMol) phenyl chloroformate were added dropwise. After stirring for 15 minutes, 20 mL (60mMol) methyl magnesium chloride (3M in tetrahydrofuran) were added dropwise and the reaction mixture was allowed to warm to room temperature.

After stirring for 30 minutes, the reaction mixture was cooledto-40 C and treated with 340 mMol potassium tertbutoxide. The reaction mixture was allowed to warm to room temperature. After stirring for 1 hour, the reaction mixture was cooled to-40 C and was treated with 200 mL saturated aqueous oxalic acid. The reaction was warmed to20 C and allowed to stir for 1 hour. The mixture was extracted 2 x 200 mL diethyl ether. The combined organic phases were washed sequentially with 4 x 100 mL 0.5 N sodium hydroxide, 2 x 100 mL saturated aqueous sodium bicarbonate, 3 x 100 mL deionized water, and 100 mL saturated aqueous sodium chloride. The remaining organics were dried over magnesium sulfate and concentrated under reduced pressure.

The residue was subjected to silica gel chromatography, eluting with hexanes containing40% ethyl acetate.

Fractions containing product were combined and concentrated under reduced pressure to provide 4.9 gm(47%) 1- (tert- butoxycarbonyl)-2-methyl-4-oxopiperidine.

回复人：bluegrass,▲▲▲ (学化学，爱化学) 时间：2005-08-12 13:04:56 编辑	1楼
呵呵，一个很好玩的反应。加 phenyl chloroformate 成季胺盐，从而CH3MgCl在2位反应上甲基，加草酸后CH3-O断裂变羰基，至于CBZ-如何变BOC－嘛？思考中，可参考文献：heterocycles,1996,2,251;pure appl.chem.1997,69,477;tetrahedron lett,1999,40,217

回复人：bluegrass,▲▲▲ (学化学，爱化学) 时间：2005-08-12 13:17:10 编辑	2楼
是它Potassium tertbutoxide (KTB)[865-47-4]，（CH3）3COK,置换掉了BnO-,heihei,so so

回复人：januswen,▲▲▲ (漫行漫随漫伫立,亦狂亦侠亦温文) 时间：2005-08-12 13:58:58 编辑	3楼
首先是形成4-甲氧基吡啶盐,然后格式试剂亲核加成得到二氢吡啶酮,叔丁醇钾交换........

回复人：quan,▲▲ (学化学，要从娃娃抓起...) 时间：2005-08-12 14:04:28 编辑	4楼
请问1楼，草酸可以脱甲基吗？这个反应我还没有见过。而且似乎还还原了一些双键。不太懂。你能否把机理给我绘出来？我查不到那些期刊原文。

回复人：januswen,▲▲▲ (漫行漫随漫伫立,亦狂亦侠亦温文) 时间：2005-08-12 14:09:08 编辑	5楼
呵呵,甲基早脱了

回复人：方无忧,★★ (有机化学是我的职业。金属有机化学是我的方向。成为一个科学家是我的理想。) 时间：2005-08-12 14:45:58 编辑	6楼
一楼说的有理。草酸脱甲基的情况，往往发生在甲氧基烯基化合物。这个化合物在上了一个甲基以后，芳环结构被破坏，可以看成是二氢吡啶。

回复人：quan,▲▲ (学化学，要从娃娃抓起...) 时间：2005-08-12 15:00:16 编辑	7楼
thanks.i see

得分人：bluegrass-3,januswen-1,方无忧-1,

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