Formamide-based prebiotic chemistry is a scientific idea that explains how life on Earth might have formed from non-living chemicals. This theory suggests that formamide (NH₂CHO), a simple compound found in nature, could have gathered in large amounts to act as a building block and environment for creating the first molecules essential for life.

Formamide contains hydrogen, carbon, oxygen, and nitrogen—elements needed to make basic life-related molecules. It is found throughout the universe, including in the centers of galaxies, areas where stars are born, young stars, space between stars, comets, and moons. Scientists have observed large clouds containing formamide near our Solar System.

Formamide forms in many environments, both on Earth and in space. For example, it can be created when high-energy particles strike mixtures of ammonia (NH₃) and carbon monoxide (CO), or when formic acid (HCOOH) reacts with ammonia. It may also collect in deep ocean vents in amounts high enough to help create life-related molecules. Computer models suggest formamide might have played a key role in experiments like the Miller–Urey experiment, which studied how life’s building blocks could form.

Carbon’s ability to form many different molecules is evident in the variety of compounds found in space. More complex carbon-containing molecules are more common than simple inorganic ones, likely throughout the universe. One of the most common three-atom carbon-containing molecules in space is hydrogen cyanide (HCN). Scientists have studied HCN since the early days of origin-of-life research, as it was used to create adenine, a molecule important for life, in laboratory experiments in 1961. However, HCN is very reactive, making it unstable and hard to collect in large amounts. For life to begin, as suggested by scientists like Charles Darwin and Alexander Oparin, conditions must have allowed HCN to build more complex molecules. This requires a stable version of HCN that can remain unchanged long enough to accumulate, but still react to form new molecules. Formamide fits this need because it is more stable than HCN and has a much higher boiling point (210 °C), allowing chemical reactions to occur over a wider range of temperatures than water.

Prebiotic chemistry

All living things on Earth are made up of four main types of large molecules: nucleic acids, proteins, carbohydrates, and lipids. Nucleic acids, such as DNA and RNA, store and use genetic information. These molecules form the genome and the tools needed to express this genetic information, which is called the genotype. Proteins, carbohydrates, and lipids create structures that take in energy from the environment and use it to build and organize materials according to the instructions from the genotype. These instructions help living things grow, survive, and pass on their traits. Together, all four types of molecules make up the phenotype. Life depends on the connection between metabolism (how energy is used) and genetics (how traits are passed on). Both metabolism and genetics rely on the most common elements in the universe: hydrogen, oxygen, nitrogen, and carbon. Other elements, like phosphorus and sulfur, also play important but smaller roles.

Scientists study how only a few types of organic molecules are used in living things, even though many more are possible. This research focuses on understanding which chemical reactions could have created the first life-related molecules on Earth long ago.

Precursor of biogenic molecules

Figure 1 shows the basic chemical structure of formamide and how it is connected to other chemicals, such as HCN and ammonium formate (NH₄HCOO), through examples of reactions that create or break down these substances.

In 1980, scientists first discovered a way to make purine using formamide. Twenty years later, in 2001, researchers expanded on this work by showing that formamide can produce many important compounds for early life, such as purine, adenine, cytosine, and 4(3H)pyrimidinone. These compounds were made by heating formamide with simple catalysts like calcium carbonate (CaCO₃), silica (SiO₂), or alumina (Al₂O₃).

In addition to nucleobases, other substances like sugars, carboxylic acids, amino acids, and complex mixtures (including urea and carbodiimide) were also created. Other catalysts tested included titanium oxides, clays, materials similar to cosmic dust, phosphates, iron sulfide minerals, zirconium minerals, borate minerals, and materials from meteorites, such as iron, stony-iron, chondrites, and achondrites.

Scientists tested different energy sources, such as heat, ultraviolet radiation, high-energy laser pulses, and slow protons. They recreated and studied scenarios that mimic how formamide might have reacted in early Earth environments, such as solar wind hitting meteorites, chemical gardens, and meteorites in water. It is believed that gradually cooling the environment could have caused chemical reactions that formed increasingly complex molecules from formamide.

For each combination of catalyst, energy source, and environment tested, formamide formed a wide range of important compounds. Each combination produced a unique set of complex molecules, often including nucleobases, amino acids, and carboxylic acids. The most complex results were found when formamide was combined with meteorite material and proton irradiation, where four nucleosides (uridine, cytidine, adenosine, and thymidine) were created in one reaction. No other one-carbon compound has shown this ability to form such a variety of products under early Earth conditions (see Figure 2).

Formamide acts as both a starting material and a solvent in reactions that create complex prebiotic compounds, such as nucleosides and long carbon chains. It also helps form molecules closer to those found in living systems. When phosphate sources (like phosphate minerals) are present, formamide helps create nucleotides by adding phosphate to nucleosides. This process also encourages the formation of RNA molecules without enzymes. Because of this, formamide is considered a likely medium for forming nucleotides in theories about how life began. Additionally, formamide can produce amino acid derivatives from simpler precursors, showing that water is not the only possible solvent for this process. Notably, formamide supports the creation of cysteine derivatives, which was previously thought unlikely in water-based environments.