North

The acronym Nor- was used in the chemical nomenclature of organic compounds to denote several different structural elements .

This type of chemical name assignment is to be regarded as semi-systematic today; it is no longer supported by the current IUPAC conventions of systematic naming . Nevertheless, many historically assigned terms with Nor- are still in use.

Various meanings have been ascribed to the abbreviation Nor- , such as “normal compound”, but also N-atom without radical or English no-radical .

use

• 

  Norepinephrine

• 

  adrenaline

• 

  L - norleucine

• 

  L - leucine

In general, it was used to indicate a structural relationship to a related chemical compound. The difference between the two structures consisted in the fact that the nor compound has one less methyl group , one methylene unit or one methine group than the reference compound. So it shows missing methyl residues, shorter side chains or rings with fewer ring members.

The respective position of a missing C-atom could be indicated with a position number ( locant ).

Natural substances

In the case of natural substances , the (sometimes multiple) demethylation compared to a parent compound was illustrated. In addition to norepinephrine, examples of this include norbixin , norcaran , norephedrine , nornicotin , norpinan and 19-nortestosterone .

amino acids

Norleucine and Norvaline are the unbranched isomers of the otherwise branched amino acids leucine and valine . The prefix Nor- stands for normal or n -amino acid and is not associated with a reduction in the number of carbon atoms.

Related acronyms

In the absence of two or more carbon atoms, the terms binor , trinor (also bisnor , trisnor, etc.) were occasionally used. The absence of longer carbon chains was indicated by the prefix apo- .

Chain extensions or ring extensions were indicated by homo- .

See also

• Prefixes and Suffixes in Chemistry

Web links

Wiktionary: nor-  - explanations of meanings, word origins , synonyms, translations

Individual evidence

1. ↑ Entry on nor- . In: IUPAC Compendium of Chemical Terminology (the “Gold Book”) . doi : 10.1351 / goldbook.N04210 Version: 2.3.1.
2. ^ A. Matthiessen, GC Foster: Researches into the chemical constitution of narcotine and of its products of decomposition . In: J. Chem. Soc. , 358, 1868. Abstract published in: Proceedings of the Royal Society of London , Volume 16, pp. 39-41.
3. ^ JH Gaddum: Book Review: The Extra Pharmacopoeia . In: Nature , 1953, 171, p. 350, doi: 10.1038 / 177350a0 .
4. ^ Entry on Nor .... In: Römpp Online . Georg Thieme Verlag, accessed on September 13, 2012.