A structural analog, also known as a chemical analog or simply an analog, is a
compound having a
structure
A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...
similar to that of another compound, but differing from it in respect to a certain component.
It can differ in one or more
atom
Atoms are the basic particles of the chemical elements. An atom consists of a atomic nucleus, nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished fr ...
s,
functional group
In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...
s, or substructures, which are replaced with other atoms, groups, or substructures. A structural analog can be imagined to be formed, at least theoretically, from the other compound. Structural analogs are often
isoelectronic.
Despite a high chemical similarity, structural analogs are not necessarily
functional analogs and can have very different physical, chemical, biochemical, or pharmacological properties.
In
drug discovery
In the fields of medicine, biotechnology, and pharmacology, drug discovery is the process by which new candidate medications are discovered.
Historically, drugs were discovered by identifying the active ingredient from traditional remedies or ...
, either a large series of structural analogs of an initial
lead compound are created and tested as part of a
structure–activity relationship
The structure–activity relationship (SAR) is the relationship between the chemical structure of a molecule and its biological activity. This idea was first presented by Alexander Crum Brown and Thomas Richard Fraser at least as early as 1868.
Th ...
study
or a database is
screened for structural analogs of a
lead compound.
Chemical analogues of
illegal drugs are developed and sold in order to circumvent laws. Such substances are often called
designer drugs. Because of this, the United States passed the
Federal Analogue Act in 1986. This bill banned the production of any chemical analogue of a
Schedule I or
Schedule II substance that has substantially similar pharmacological effects, with the intent of human consumption.
Examples
Neurotransmitter analog
A neurotransmitter analog is a structural analogue of a
neurotransmitter
A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a Chemical synapse, synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell.
Neurotra ...
, typically a
drug
A drug is any chemical substance other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect. Consumption of drugs can be via insufflation (medicine), inhalation, drug i ...
. Some examples include:
*
Catecholamine analogue
*
GABA analogue
*
Serotonin analogue
See also
*
Derivative (chemistry)
*
Functional analog, compounds with similar physical, chemical, biochemical, or pharmacological properties
*
Homolog, a compound of a series differing only by repeated units
*
Transition state analog
References
{{Reflist
External links
Analoging in ChEMBL, DrugBank and the Connectivity Map– a free web-service for finding structural analogs in
ChEMBL,
DrugBank, and the Connectivity Map
Chemical nomenclature