Biological activity nomenclature

The lUPAC-IUB Commission on Biochemical Nomenclature (13) recommends that the term vitamin B 2 be used as the genetic descriptor for aU. cottiaoids exhibiting quaUtatively the biological activity of cyanocobalamin. However, because of its commercial importance, cyaaocobalamin is used iaterchangeably with vitamin B 2 heteia. 

Benzonaphthyridines, 2, 581-627 nomenclature, 2, 612 synthesis, 2, 612 Benzo-1,5-naphthyridines biological activity, 2, 625 Benzo[/i][ 1,5]naphthyridines photoelectron spectra, 2, 585 Benzo[/i][l, 6]naphthyridines photoelectron spectra, 2, 585 synthesis, 2, 613 Benzo[/][l, 7]naphthyridines photoelectron spectra, 2, 585 synthesis, 2, 613 Benzo-1,8-naphthyridines synthesis, 2, 608... 

Homofolic acid, 5,11-methenyl-tetrahydro-biological activity, 3, 327 Homofolic acid, tetrahydro-biological activity, 3, 327 Homoisoflavanones occurrence, 3, 722 thermoisomerization, 3, 722 thermolysis, 3, 728 Homolytic reactions heterocyclic compounds reviews, 1, 74 Homophthalic acid isocoumarins synthesis from, 3, 830 synthesis, 3, 830 Homophthalic anhydride isochroman-l-one synthesis from, 3, 860 20a-Homoporphyrin nomenclature, 1, 30 Homopterocarpin isolation, 4, 998 ( )- D- Homotestosterone synthesis, 1, 453 Homer-Emmons reaction chromene synthesis by, 3, 749 Hortiacine isolation, 3, 149 Hortiamine isolation, 3, 149... 

As a consequence of these favorable structural features and because of their considerable biological activity,a substantial effort has been devoted to a continued search for new analogs. The proposed and by now well-established system of nomenclature (see Section 11.2) will be used, leading in some instances to a change of published names as far as the a,(3-designations are concerned. New entries are listed in Table 11.15. 

The classical progestins as well as the corticosteroids arc based on a steroid nucleus that incorporates a two-carbon side chain at the 17 position that often includes a carbonyl group at position 21. The hypothetical parent hydrocarbon has been assigned the name pregnane for purposes of nomenclature. While two classes of compounds, progestins and corticoids, share common biosynthetic pathways, their biological activities differ markedly. 

In addition to systematic chemical nomenclature, the vitamins have an apparently illogical system of accepted trivial names arising from the history of their discovery (Table 1.1). For several vitamins, a number of chemically related compounds show the same biological activity, because they are either converted to the same final active metabolite or have sufficient structural similarity to have the same activity. 

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