Tertiary-butoxycarbonyl (Boc) – A strategic group for N-protection/deprotection in the synthesis of various natural/unnatural N-unprotected aminoacid cyanomethyl esters
作者:Ananta Karmakar、Mushkin Basha、G.T. Venkatesh Babu、Murali Botlagunta、Noormohamed Abdul Malik、Richard Rampulla、Arvind Mathur、Arun Kumar Gupta
DOI:10.1016/j.tetlet.2018.10.041
日期:2018.11
available 4M HCl in 1,4-dioxane solution (2–4 equiv); acetonitrile, 0 °C, 2–4 h was a suitable condition. This condition was generalized and successfully applied to a variety of alkyl, alkynyl, aryl, heteroaryl, benzyl, azido, spiro amino acid cyanomethylesters irrespective of the nature of the amine (primary or secondary) and the distance between the amine and ester group to achieve final deprotected
由于它们的合成和医学重要性,合成了许多具有未保护的氨基官能度的天然/非天然氨基酸的氰基甲基酯。彻底筛选了在不稳定(水解敏感性)氰甲基官能团存在下的重要N- Boc脱保护方法,发现在1,4-二恶烷溶液(2-4当量)中易于获得的4M HCl。乙腈,0°C,2-4 h是合适的条件。此条件已被推广,并成功应用于各种烷基,炔基,芳基,杂芳基,苄基,叠氮基,螺氨基酸氰基甲基酯,而与胺的性质(伯或仲)以及胺与酯基之间的距离无关最终脱保护的氨基酯,具有较高的收率和纯度(与其他通常已知的相比)N-保护基(Cbz,Fmoc,Ac,Bn,Bz等)。还证明了与N-未保护的对应物相比,N- Boc保护的氨基酸氰基甲基酯足够稳定以进行进一步的官能化。