Ajmalan
Encyclopedia
Ajmalan is a parent hydride
used in the IUPAC nomenclature
of natural products and also in CAS nomenclature. It is a 20-carbon alkaloid
with six rings and seven chiral centres
.
The name is derived from ajmaline
, an antiarrhythmic
alkaloid isolated from the roots of Rauwolfia serpentina
which is formally a dihydroxy-derivative of ajmalan. The –an ending indicates that ajmalan is partially saturated. Ajmaline itself is named after Hakim Ajmal Khan
, a distinguished practitioner of the Unani
school of traditional medicine in South Asia
.
The absolute configuration of the seven chiral
carbon atoms in ajmalan is defined by convention, as is the numbering system. The stereochemistry is the same as that in naturally-occurring ajmaline
, and corresponds to (2R,3S,5S,7S,15S,16R,20S) using conventional numbering.
Ajmalan can be systematically named as-4-ethyl-9-methyl-2,9-diazahexacyclo[14.2.1.02,7.05,18.08,16.010,15]nonadeca-10,12,14-triene
or as-4H,11H-3-ethyl-11-methyl-1,2,3,5,6,6a,11a,11b-octahydro-2,5,6a-(epiethane[1,1,2]triyl)indolo[2,3-c]quinolizine.
Note that the numbering of the atoms in the systematic names is different from the conventional numbering of ajmalan.
The ajmalan skeleton is similar to those of certain other alkaloids, and ajmalan could also be given the following semisystematic names:-1-methyl-1,2,19,20-tetrahydro-5,16-cyclo-16a-homo-17-norakuammilan;-1-methyl-2,7-dihydro-5,16:7,17-dicyclocorynan;-1-methyl-2,7,19,20-tetrahydro-7,17-cyclosarpagan;-1-methyl-2,7,19,20-tetrahydro-3,4:7,17-dicyclo-22-norvobasan;-1-methyl-2,7-dihydro-5,16:7,17-dicyclo-17-secoyohimban
.
However, the relative complexity even of these names justifies the use of ajmalan as a defined parent hydride in alkaloid nomenclature.
Parent hydride
In IUPAC nomenclature, a parent hydride is an unbranched acyclic or cyclic structure to which only hydrogen atoms are attached. Parent hydrides are parent structures that contain one or more hydrogen atoms...
used in the IUPAC nomenclature
IUPAC nomenclature
A chemical nomenclature is a set of rules to generate systematic names for chemical compounds. The nomenclature used most frequently worldwide is the one created and developed by the International Union of Pure and Applied Chemistry ....
of natural products and also in CAS nomenclature. It is a 20-carbon alkaloid
Alkaloid
Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids...
with six rings and seven chiral centres
Chirality (chemistry)
A chiral molecule is a type of molecule that lacks an internal plane of symmetry and thus has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom....
.
The name is derived from ajmaline
Ajmaline
Ajmaline is a class Ia antiarrhythmic agent. It is often used to bring out typical findings of ST elevations in patients suspected of having Brugada syndrome....
, an antiarrhythmic
Antiarrhythmic agent
Antiarrhythmic agents are a group of pharmaceuticals that are used to suppress abnormal rhythms of the heart , such as atrial fibrillation, atrial flutter, ventricular tachycardia, and ventricular fibrillation....
alkaloid isolated from the roots of Rauwolfia serpentina
Rauwolfia serpentina
Rauvolfia serpentina, or 'snakeroot' or 'sarpagandha' is a species of flowering plant in the family Apocynaceae.-Medicinal uses:It is one of the 50 fundamental herbs used in traditional Chinese medicine, where it has the name shégēn mù or yìndù shémù .Rauwolfia serpentina contains a number of...
which is formally a dihydroxy-derivative of ajmalan. The –an ending indicates that ajmalan is partially saturated. Ajmaline itself is named after Hakim Ajmal Khan
Hakim Ajmal Khan
Ajmal Khan was an Indian physician specialising in the field of South Asian traditional Unani medicine as well as a Muslim nationalist politician and freedom fighter. Through his founding of the Tibbia College in Delhi, he is credited with the revival of Unani medicine in early 20th century...
, a distinguished practitioner of the Unani
Unani
Unani-tibb or Unani Medicine also spelled Yunani Medicine means "Greek Medicine", and is a form of traditional medicine widely practiced in South Asia...
school of traditional medicine in South Asia
South Asia
South Asia, also known as Southern Asia, is the southern region of the Asian continent, which comprises the sub-Himalayan countries and, for some authorities , also includes the adjoining countries to the west and the east...
.
The absolute configuration of the seven chiral
Chirality (chemistry)
A chiral molecule is a type of molecule that lacks an internal plane of symmetry and thus has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom....
carbon atoms in ajmalan is defined by convention, as is the numbering system. The stereochemistry is the same as that in naturally-occurring ajmaline
Ajmaline
Ajmaline is a class Ia antiarrhythmic agent. It is often used to bring out typical findings of ST elevations in patients suspected of having Brugada syndrome....
, and corresponds to (2R,3S,5S,7S,15S,16R,20S) using conventional numbering.
Ajmalan can be systematically named as-4-ethyl-9-methyl-2,9-diazahexacyclo[14.2.1.02,7.05,18.08,16.010,15]nonadeca-10,12,14-triene
or as-4H,11H-3-ethyl-11-methyl-1,2,3,5,6,6a,11a,11b-octahydro-2,5,6a-(epiethane[1,1,2]triyl)indolo[2,3-c]quinolizine.
Note that the numbering of the atoms in the systematic names is different from the conventional numbering of ajmalan.
The ajmalan skeleton is similar to those of certain other alkaloids, and ajmalan could also be given the following semisystematic names:-1-methyl-1,2,19,20-tetrahydro-5,16-cyclo-16a-homo-17-norakuammilan;-1-methyl-2,7-dihydro-5,16:7,17-dicyclocorynan;-1-methyl-2,7,19,20-tetrahydro-7,17-cyclosarpagan;-1-methyl-2,7,19,20-tetrahydro-3,4:7,17-dicyclo-22-norvobasan;-1-methyl-2,7-dihydro-5,16:7,17-dicyclo-17-secoyohimban
Yohimban
Yohimban is a chemical compound. It is the base chemical structure of various alkaloids in the Rauwolfia and Pausinystalia plant genuses, including yohimbine, rauwolscine, corynanthine, ajmalicine, reserpine, deserpidine, and rescinnamine, among others....
.
However, the relative complexity even of these names justifies the use of ajmalan as a defined parent hydride in alkaloid nomenclature.