Derivative (chemistry)

As a derivative (from the Latin derivare "derived" ) is referred to in chemistry a derived substance similar structure to a corresponding matrix ( parent compound ). Derivatives are substances which, in place of an H atom or a functional group whose molecules have another atom or another atomic group, or in which one or more atoms / groups of atoms removed. Derivatives of a parent compound usually have significantly different chemical and physical properties compared to the parent compound. The preparation of a derivative is referred to as derivatization.

Examples

Refers carboxamides, carboxylic anhydrides, carboxylic acid halides, and nitriles as derivatives of the corresponding carboxylic acid, as they are obtainable by modification of functional groups in the latter. Alcohols and ethers can be formally described as derivatives of the water having the structure

View. If, for the remainder R is hydrogen, we obtain water ( HOH), are employed for the methyl radical CH3 R, we obtain methanol ( CH 3 OH).

Derivatives of ethane, for example,

• Ethanol
• Ethene
• Ethyne
• Acetaldehyde ( ethanal )
• Acetic acid ( ethanoic acid )
• Chloroethane
• Ethylamine ( aminoethan )

Homologous series

Must be distinguished from the term derivative of the term homologue. Homologs are substances that differ only by the chain length of their basic building blocks; in Organic Chemistry, these are the hydrocarbon chains as alkanes, alkenes, alcohols, or carboxylic acids. Members of this homologous series are in their chemical and physical properties are often very similar. Homologues are not derivatives in most cases.

The importance of derivatives

In pharmacy, the derivatization is of particular importance in order to create from existing drugs new and potentially more effective or better tolerated drugs. For example, acetylsalicylic acid ( the major component and active ingredient in aspirin ), a derivative of salicylic acid, that is, the medicinally active substance. Another example is acetaminophen, the better tolerated derivative of the acetanilide.

Throughout the chromatographic analytical derivatives play an important role. In gas chromatography and gas chromatography -mass spectrometry derivatives are mostly used to convert or only difficult to vaporize analytes in more volatile derivatives of chromatography in the gas phase accessible. In HPLC frequently chromophoric and / or fluorophoric derivatives are used, to allow the sensitive and specific detection in the visible or ultraviolet spectral range.