Nomenclature of Lignans and Neolignans (IUPAC Recommendations 2000)
G.P. Moss
Department of Chemistry, Queen Mary and Westfield College,
Mile End Road, London, E1 4NS, UK
World
Wide Web version prepared by G. P. Moss
Abstract: 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.
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