Department of Chemical Sciences (APK Campus), University of Johannesburg, PO Box 524, Auckland Park, Johannesburg, 2006, South Africa.
J Mol Model. 2019 Nov 9;25(11):335. doi: 10.1007/s00894-019-4224-z.
Calculations related to two simple two-step paths (path-I: [Formula: see text] path-II: [Formula: see text]) for the formation of glycine have been discussed. Calculations show that at interstellar conditions these two paths are feasible only in hot cores, not in the cold interstellar clouds (cold core formation is possible only if CH = NH, HO (excess) and CO of path-II, react in a concerted manner). For the laboratory synthesis of glycine, the possibility suggested is via path-I and the reaction being carried out as controlled temperature one-pot synthesis. This study can also be extended to other α-amino acids and possibly enantiomeric excess can be expected. We think this work will not only be able to enrich our future understanding about the formation of amino acids in interstellar medium but also be able to suggest alternative paths for laboratory synthesis of amino acids using either Strecker's or Miller's ingredients. Graphical abstract Using computational calculations, two different reaction paths which go through a hemiaminal (α-hydroxyamine) intermediate have been proposed. It has been proposed that the reaction [Formula: see text] is a thermodynamically favorable reaction path in the laboratory conditions, if carried out as a controlled temperature one-pot synthesis. On the hand, it has been argued that the reaction[Formula: see text] is a feasible reaction path in the interstellar conditions, if it proceeds not via the hemiaminal route, rather in a concerted reaction path.
已经讨论了两种简单的两步路径(路径-I:[公式:见文本]路径-II:[公式:见文本])形成甘氨酸的相关计算。计算表明,在星际条件下,这两种路径仅在热核中可行,而不在冷星际云中可行(只有当 CH = NH、HO(过量)和 CO 按照协同方式反应时,冷核形成才有可能)。对于甘氨酸的实验室合成,建议通过路径-I 进行,并且反应作为控温一锅合成进行。这项研究也可以扩展到其他α-氨基酸,并且可能会产生对映体过量。我们认为这项工作不仅能够丰富我们对星际介质中氨基酸形成的未来理解,还能够为使用斯特雷克或米勒成分的氨基酸实验室合成提出替代途径。
图摘要
使用计算计算,已经提出了两种不同的反应路径,它们都经过半亚胺(α-羟胺)中间体。如果作为控温一锅合成进行,则提出反应[公式:见文本]是实验室条件下的热力学有利反应路径。另一方面,已经有人认为,如果[公式:见文本]反应不是通过半亚胺途径,而是通过协同反应途径进行,那么它在星际条件下是可行的反应途径。