Debenzylation of Tertiary Amines Using Phosgene or Triphosgene: An Efficient and Rapid Procedure for the Preparation of Carbamoyl Chlorides and Unsymmetrical Ureas. Application in Carbon-11 Chemistry
作者:Laurent Lemoucheux、Jacques Rouden、Méziane Ibazizene、Franck Sobrio、Marie-Claire Lasne
DOI:10.1021/jo0346297
日期:2003.9.1
Taking advantage of this observation, a strategy of synthesis of carbamoyl chlorides from tertiary amines and phosgene has been developed. N-Alkyl-N-benzyl(substituted)tetrahydroisoquinolines, -piperazines, -piperidines, or -anilines were treated with stoichiometric amounts of phosgene (or BTC) in CH(2)Cl(2). Tertiary amines bearing electron-enriched benzyl group(s) afforded carbamoyl chlorides in excellent
描述了从叔胺和光气或其安全等效的三光气[双(三氯甲基)碳酸酯,BTC]高效快速地制备氨基甲酰氯和不对称脲的方法。首先,重新讨论了化学计量的光气与仲胺的反应,结果表明,高产率的氨基甲酰氯的形成需要仔细调整实验条件,并使用吡啶作为HCl清除剂。当使用该碱代替吡啶时,观察到光气介导的三乙胺脱烷基化。利用这种观察,已经开发了从叔胺和光气合成氨基甲酰氯的策略。N-烷基-N-苄基(取代)四氢异喹啉,-哌嗪,-哌啶,或-苯胺用化学计量的光气(或BTC)在CH(2)Cl(2)中处理。带有电子富集的苄基的叔胺以优异的收率提供了氨基甲酰氯,且不受对称尿素的任何污染。随后向这些氨基甲酰氯中添加伯胺或仲胺会在单罐和高产率操作中产生不对称的脲。该方法应用于(11)C-化学。从[(11)C]光气(一种用于制备正电子发射断层扫描的放射性示踪剂的常用前体)快速高效地合成衍生自四氢异喹啉和哌嗪的(11)C-氨基甲酰氯和(11)C-不对称尿素。描述。