Theoretical Study of the Addition of Hydrogen Cyanide to Methanimine in the Gas Phase and in Aqueous Solution

Abstract

We have performed a detailed study of the title reaction, which is the key step of one of the most realistic processes suggested for the prebiotic synthesis of amino acids. From a methodological point of view, our results confirm the reliability of the integrated computational tool formed by the B3LYP density functional model and the polarizable continuum model for the description of solvent effects. From a more chemical point of view, the reaction is quite unlikely in the gas phase due to the presence of significant reaction barriers, whereas the aqueous medium leads to a more feasible mechanism thanks to the preferential solvation of zwitterionic transition structures. Both specific and bulk solvent effects play a role in determining the overall mechanism.

Attractive noncovalent interactions in asymmetric catalysis: Links between enzymes and small molecule catalysts

“…9). In this pathway, which is qualitatively similar to the proposed mechanism for Strecker reactions carried out in protic solvents, a thiourea-bound HCN (or HNC) first transfers its acidic proton to the imine substrate (51). The resulting contact ion pair then undergoes rearrangement to separate the charged species, which is accomplished by transferring the hydrogen bonding interaction of the protioiminium ion N-H from the bound cyanide to the carbonyl of the catalyst amide.…”

Effects of pathological mutations on the stability of a conserved amino acid triad in retinoschisin

“…For these calculations the 6-311+G(d,p) basis set was used. Solvent e¡ects were evaluated using the polarizable continuum PCM model [25,26], which has been tested in several studies on biological systems [27,28]. The Gaussian98 package was used for all the calculations [29].…”

Dimerization of methanimine and its charged species in the atmosphere of Titan and interstellar/cometary ice analogs

“…Methanimine, CH 2 =NH, is alleged to be an important species in prebiotic chemistry since it is a possible precursor of the simplest amino acid, glycine, via its subsequent reactions with HCN and H 2 O (Balucani 2009(Balucani , 2012Woon 2002), and it is an essential intermediate in the Strecker synthesis of aminoacetonitrile (Danger et al 2011) and glycine (Rimola et al 2010;Ugliengo et al 2011;He & Smith 2014;Holtom et al 2005;Arnaud et al 2000). Methanimine was observed a long time ago in the interstellar medium (Godfrey et al 1973).…”