Inorganic chemistry, acondensation reaction is a type ofchemical reaction in which twomolecules arecombined to form a single molecule, usually with the loss of a small molecule such aswater.[1] If water is lost, the reaction is also known as adehydration synthesis. However other molecules can also be lost, such asammonia,ethanol,acetic acid andhydrogen sulfide.[2]
The addition of the two molecules typically proceeds in a step-wise fashion to the addition product, usually inequilibrium, and with loss of a water molecule (hence the namecondensation).[3] The reaction may otherwise involve thefunctional groups of the molecule, and is a versatile class of reactions that can occur inacidic orbasic conditions or in the presence of acatalyst. This class of reactions is a vital part of life as it is essential to the formation ofpeptide bonds betweenamino acids and to thebiosynthesis of fatty acids.[4]
Many variations of condensation reactions exist. Common examples include thealdol condensation and theKnoevenagel condensation, which both form water as a by-product, as well as theClaisen condensation and theDieckman condensation (intramolecular Claisen condensation), which form alcohols as by-products.[5]
Condensation reactions likely played major roles in the synthesis of the first biotic molecules including earlypeptides andnucleic acids. In fact, condensation reactions would be required at multiple steps inRNA oligomerization: the condensation ofnucleobases andsugars,nucleosidephosphorylation, andnucleotide polymerization.[6]
