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Publicado por: Alessandra Franchi
~ 12/09/08
Lignans and neolignans are a large group of natural products characterized by the coupling of two C6C3 units. For nomenclature purposes the C6C3 unit is treated as propylbenzene and numbered from 1 to 6 in the ring, starting from the propyl group, and with the propyl group numbered from 7 to 9, starting from the benzene ring. With the second C6C3 unit the numbers are primed. When the two
C6C3 units are linked by a bond between positions 8 and 8′ the compound is referred to and named as a lignan. In the absence of the C-8 to C-8′ bond, and where the two C6C3 units are linked by a carbon–carbon bond it is referred to and named as a neolignan. The linkage with neolignans may include C-8 or C-8′.
Where there are no direct carbon–carbon bonds between the C6C3 units and they are linked by an ether oxygen atom the compound is named as an oxyneolignan.
The nomenclature provides for the naming of additional rings and other modifications following standard organic nomenclature procedures for naming natural products. Provision is included to name the higher homologues. The sesquineolignans have three C6C3 units, and dineolignans have four C6C3 units.
Pure & Appl. Chem., Vol. 72, No. 8, p. 1493–1523, 2000
© 2000 IUPAC
IUPAC permission is acknowledged
Publicado por: Alessandra Franchi
These Recommendations expand and replace the Tentative Rules for Carbohydrate Nomenclature [11] issued in 1969 jointly by the IUPAC Commission on the Nomenclature of Organic Chemistry and the TUB-IUPAC Commission on Biochemical Nomenclature (CBN) and reprinted in [2]. They also replace other published JCBN Recommendations [3-71] that deal with specialized areas of carbohydrate terminology; however, these documents can be consulted for further examples. Of relevance to the field, though not incorporated into the present document, are the following recommendations:
- Nomenclature of cyclitols, 1973 [8]
- Numbering of atoms in myo-inositol, 1988 [9]
- Symbols for specifying the conformation of polysaccharide chains, 1981 [10]
- Nomenclature of glycoproteins, glycopeptides and peptidoglycans, 1985 [11]
- Nomenclature of glycolipids, in preparation [12]
The present Recommendations deal with the acyclic and cyclic forms of monosaccharides and their simple derivatives, as well as with the nomenclature of oligosaccharides and polysaccharides. They are additional to the Definitive Rules for the Nomenclature of Organic Chemistry [13,14] and are intended to govern those aspects of the nomenclature of carbohydrates not covered by those rules.
Pure & Appl. Chem., Vol. 68, No. 10, p. 1919-2008, 1996
© 1996 IUPAC
IUPAC permission is acknowledged