Allopumiliotoxin - Nomenclature

Nomenclature

There are three divisions within the pumiliotoxin-A class: allopumiliotoxins, pumiliotoxins, and homopumiliotoxins. Once the compound’s specific class is determined, it’s given a number based on its molecular weight. These biologically active compounds are complex and have structural variations that allow for specific molecular recognition. Therefore, the way 2 isomers are differentiated is by a letter after the number. Therefore, for example, allopumiliotoxin 339A is an allopumiliotoxin with a molecular weight of 339 g/mol but there are other isomers with the same molecular weight. Allopumiliotoxin 339A has an axially oriented hydroxyl group at the 7-position in the indolizidine nucleus that differentiates it from allopumiliotoxin 339B. A (+) or (-) sign preceding the name of an allopumiliotoxin refers to the compound’s optical activity. Compounds that rotate a plane of polarized light clockwise are referred to as dextrorotatory and are preceded by a (+) sign. Compounds that rotate a plane of polarized light counterclockwise are referred to as levorotatory and are preceded by a (-) sign.