Formamide-based prebiotic chemistry

Formamide-based prebiotic chemistry is a reconstruction of the beginnings of life on Earth, assuming that formamide could accumulate in sufficiently high amounts to serve as the building block and reaction medium for the synthesis of the first biogenic molecules.

[2] Formamide has been detected in galactic centers,[3][4] star-forming regions of dense molecular clouds,[5] high-mass young stellar objects,[6] the interstellar medium,[7] comets,[8][9][10] and satellites.

[5] Formamide forms under a variety of conditions, corresponding to both terrestrial environments and interstellar media: e.g., on high-energy particle irradiation of binary mixtures of ammonia (NH3) and carbon monoxide (CO),[12] or from the reaction between formic acid (HCOOH) with NH3.

[24] A series of studies building on this observation was started 20 years later: the synthesis of a large panel of prebiotically relevant compounds (including purine, adenine, cytosine, and 4(3H)pyrimidinone) in good yields was reported in 2001.

[37] It has been suggested that the stepwise decrease of the temperature of the prebiotic environment could induce a sequence of strongly non-equilibrium chemical events that led to the emergence of more and more complex species from formamide on the early Earth.

[1] The highest level of complexity was attained for the formamide/meteorite system,[27] using proton irradiation as the energy source, where the one-pot synthesis of four nucleosides (uridine, cytidine, adenosine, thymidine) was observed.

[39] In addition to its dual function of substrate and solvent in one-pot syntheses affording prebiotic compounds as complex as nucleosides and long aliphatic chains,[37] it has been observed that formamide plays a role in the generation of molecules which are closer to the biological domain.

[43][44] As well as phosphorylation, formamide has been shown to be a competent medium for the production of amino acid derivatives from their simple aldehyde and nitrile precursors, demonstrating that water is not the only solvent that this process can occur in.

Figure 1. Relationship between formamide and other prebiotic feedstock molecules, such as HCN and ammonium formate.[1]
Figure 1. Relationship between formamide and other prebiotic feedstock molecules, such as HCN and ammonium formate(NH 4 + HCOO − ). [ 1 ]
Figure 2. Main prebiotic building blocks that can be synthesized from formamide under plausible prebiotic conditions.[1]
Figure 2. Main prebiotic building blocks that can be synthesized from formamide under plausible prebiotic conditions. [ 1 ] , [ 26 ]