Methylenecyanamide (CH2═NCN) and (Z)- and (E)-Iminoacetonitriles (NC-CH═NH), Dimers of Hydrogen Cyanide.

(Z)- and (E)-iminoacetonitriles (NCCH═NH), two hydrogen cyanide dimers, are described as key compounds in prebiotic chemistry. Among the many possible dimers of HCN with covalent bonds, even the second on the scale of thermodynamic stability, methylenecyanamide (CH2═NCN), has been investigated little. We show that this compound can be isolated, is stable enough to give an adduct with a nucleophile or a diene, and can be easily generated under prebiotic conditions, highlighting a possible role in this medium. Comparison between isomers shows significant differences in formation and chemical reactivity.

Gas-phase identification of (Z)-1,2-ethenediol, a key prebiotic intermediate in the formose reaction.

Prebiotic sugars are thought to be formed on primitive Earth by the formose reaction. However, their formation is not fully understood and it is plausible that key intermediates could have formed in extraterrestrial environments and subsequently delivered on early Earth by cometary bodies. 1,2-Ethenediol, the enol form of glycolaldehyde, represents a highly reactive intermediate of the formose reaction and is likely detectable in the interstellar medium. Here, we report the identification and first characterization of (Z)-1,2-ethenediol by means of rotational spectroscopy. The title compound has been produced in the gas phase by flash vacuum pyrolysis of bis-exo-5-norbornene-2,3-diol at 750 °C, through a retro-Diels-Alder reaction. The spectral analysis was guided by high-level quantum-chemical calculations, which predicted spectroscopic parameters in very good agreement with the experiment. Our study provides accurate spectral data to be used for searches of (Z)-1,2-ethenediol in the interstellar space.

Synthesis of N-unsubstituted cycloalkylimines containing a 4 to 8-membered ring.

Primary cycloalkylimines with a 4 to 8-membered ring were synthesized by dehydrocyanation of the corresponding α-aminonitriles on solid potassium hydroxide via a vacuum gas-solid reaction. Imine-enamine tautomerism has been demonstrated at room temperature for the most kinetically stable derivatives.