Appendix D
The Prefix NorThe prefix nor- is being used in chemical nomenclature with several meanings, and for that reason is a rather ambiguous term. The Chemical Abstracts booklet (6, pp. 5953-54) defines nor- as follows: nor- from normal; (a) indicating the parent from which another compound may be theoretically derived, usually by the removal of one or more carbon atoms (and attached hydrogen); as, norcamphane (of which camphane is a trimethyl derivative); (b) designating a compound of normal structure isomeric with the one to the name of which it is prefixed; as, norleucine. Meaning (a) — that i s , stripping to a parent ring skeleton by the replacement of methyl groups by hydrogen — has been the one generally used by terpene chemists. The American committees agreed that the use of nor- in meaning (b) should be discouraged. Although there is nothing in the name ' ' n o r " to suggest the replacement of a C H 3 by H or the elimination of CH2 adjacent to COOH, this definition states correctly the current steroid usage. The most common use of nor- in nonsteroid chemistry occurs in the names of alkaloids; here the prefix indicates the replacement of one C H 3 group by H in an N C H 3 group. In the June 1952 version of the terpene nomenclature report, the recommendation was made to modernize the traditional terpene definition of the prefix nor- so that in a name it would denote a ring system devoid of all side chains rather than of only methyl groups. On this basis, the name "northujane" would be valid and fit in logically with the bicyclic series of names: norcarane, norpinane, and norbornane. Evidence from the chemical literature for the occasional use of nor- to denote stripping of an isopropyl group as well as a methyl group is: norsab inane (a synonym for northujane) in Richter's organic text(32,pp. 53,240); northujane in Berichte(27); northujonedicarboxylic acid (with an asterisk) in the Third Decennial Index of Chemical Abstracts; and normenthane (a synonym for cyclohexane) in Mitchell's book (36, pp. 39, 120). However, majority opinion ruled out the recommended modernization of the definition of nor-, and thus the name northujane, at the meeting of the Nomenclature Committee, Division of Organic Chemistry, in Chicago, 111., September 5, 1953. In the final report, therefore, the name bicycloQ3.1.0^hexane rather than northujane is recommended for the bicyclo ring structure of thujane.
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