Thioamide bonds are important intermediates in prebiotic chemistry. In cyanosulfidic prebiotic chemistry, they serve as crucial intermediates in the pathways that lead to the formation of many important biomolecules (e.g., amino acids). They can also serve as purine and pyrimidine precursors, the two classes of heterocycle employed in genetic molecules. Despite their importance, the formation of thioamide bonds from nitriles under prebiotic conditions has required large excesses of sulfide or compounds with unknown prebiotic sources. Here, we describe the thiol-catalyzed formation of thioamide bonds from nitriles. We show that the formation of the simplest of these compounds, thioformamide, forms readily in spark-discharge experiments from hydrogen cyanide, sulfide, and a methanethiol catalyst, suggesting potential accumulation on early Earth. Lastly, we demonstrate that thioformamide has a Gibbs energy of hydrolysis ( $$\Delta G^{\circ }_r$$ ) comparable to other energy-currencies on early Earth such as pyrophosphate and thioester bonds. Overall, our findings imply that thioamides might have been abundant on early Earth and served a variety of functions during chemical evolution.

中文翻译：

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益生元硫醇催化的硫代酰胺键形成


硫代酰胺键是生命起源化学中的重要中间体。在氰硫基生命前化学中，它们作为导致许多重要生物分子（例如氨基酸）形成的途径中的关键中间体。它们还可以作为嘌呤和嘧啶前体，这是遗传分子中使用的两类杂环。尽管它们很重要，但在益生元条件下从腈形成硫代酰胺键需要大量过量的硫化物或未知益生元来源的化合物。在这里，我们描述了硫醇催化的腈形成硫代酰胺键。我们表明，在火花放电实验中，氰化氢、硫化物和甲硫醇催化剂很容易形成这些化合物中最简单的硫代甲酰胺，这表明早期地球上可能存在积累。最后，我们证明硫代甲酰胺具有与早期地球上的其他能源货币（例如焦磷酸盐和硫酯键）相当的吉布斯水解能（ $$\Delta G^{\circ }_r$$ ）。总的来说，我们的研究结果表明，硫代酰胺在早期地球上可能含量丰富，并在化学进化过程中发挥着多种作用。