NOMENCLATURE by Austin M. Patterson
"Chemical Purity" Again In a previous issue (C&EN, 3 1 , 4129, 1953) the terms denoting various degrees of purity in chemicals were discussed. There it w a s stated that " C . P . , " though ambiguous, continues to b e used to a limited degree. In the latest Fisher Scientific C o . catalog (115C, "Fisher Chemical Index") " C . P . " has been eliminated altogether. In place of "Pure," t h e term "Purified" is used for chemicals that have been purified beyond the technical grade, to a point where they may b e used in the laboratory for synthesis, albeit not for analytical work. T h e catalog contains 7344 items. The Prefix " N o r " The prefix nor is derived from the word "normal." Originally used to denote the complete stripping of side chains from a ring system, it has become somewhat ambiguous. T h r e e uses can now be distinguished, t o denote: ( 1 )
Complete stripping, as in norpinane (pinane in which the three methyl groups have been replaced by hydrogen, leaving the parent system, b i c y c l o [3.1.1]heptane). This is the use common in terpene chemistry; it is adopted in the Grafflin report (C&EN, 30, 930, 1 9 5 2 ) . (2) Elimination of a single CH2, either from a methyl group or from a chain; two such eliminations are denoted preferably by "dinor" (but also often by "bisnor"). This is the use favored in the steroid field and to some extent elsewhere: as, norcholane. dinorpregnane, nornicotine. ( 3 ) A straightchain isomer of a branched-chain compound; as, norleucine. There are only a few instances of sense 3, and it should be discouraged. Senses 1 and 2 seem so firmly established in their respective fields that apparently both must be recognized. Numbering of Radicals Some chemists wonder why International Union rule 6 5 requires that aliphatic radicals be numbered from the point of attachment. T h e y think that, for instance, we might conveniently
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A M I N O A C I D S O . S. (OPTICALLY
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L- a n d D-Isomers ALSO A V A I L A B L E Schwarz K i t s of Natural Amino Acids O.S. ( Optically Standarized) S35,-labeled L-cystine and L-methionine C 1 4 - uniformly labeled L-arginine, L-aspartic acid, L-glutamic acid, L-histidinc, L-lysine, L-phenylalanine and L-tyrosine; yeast protein hydrolyzates. Specify
Schwarz
SCHWARZ 230
1818
F o r highest precision in c h r o m a t o g r a p h y , microbiological assay, n u t r i tion, s y n t h e s e s , a n d all o t h e r e x a c t ing r e q u i r e m e n t s for a m i n o acids.
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in
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A Nomenclature Guidebook Decisions on chemical nomenclature now exist i n the form of various reports and articles, some of w h i c h are not readily available. It would b e helpful if the most important of these w e r e collected together under one cover. Such a collection was planned by H . S. Nutting, former chairman of t h e Committee on Nomenclature of the ACS Division of Organic Chemistry, a n d t h e project is being kept alive by t h e present chairman, Mary Alexander. T h e idea would be t o prepare it as inexpensively as possible and to revise it from time t o time. There is a b u n d a n t material for such a guidebook to chemical nomenclature, but its feasibility d e p e n d s on h o w much demand there would be for it. If you are interested write to Miss Alexander, Universal Oil Products Co., 3 0 Algonquin Road, Des Plaines, Ill. and give her your ideas as to w h a t you think of the plan, what should b e included, and how it could be published. Glyodin
W r i t e for o u r Price List showing specific r o t a t i o n r a n g e s for our O. S . ( O p t i c a l l y S t a n d a r d i z e d ) g r a d e . E v e r y p a c k a g e label gives t h e e x a c t r o t a t i o n of t h e lot s h i p p e d . P e r c e n t n i t r o g e n is w i t h i n ± 0 . 1 of theoretical v a l u e .
for assurance
have 1-hexyl, 2-hexyl, and 3-hexyl, in which the 1-6 numbering of hexane would be preserved b u t the positions of attachment would be different; whereas now we have to write 1-methylpentyl instead of 2-hexyl and 1-ethylbutyl instead of 3-hexyl. T h e answer, we think, is that the advocated m e t h o d has been tried, and leads to complications, especially a s to t h e meaning of t h e prefixed number. F o r example, w h a t is 2hexylthiophene? At present the meaning is dear, for there is only one "hexyl"; but if the 2 could refer either to the hexyl or to the thiophene the name would be ambiguous. T r u e , the "2-hexyl" could be enclosed in parentheses to show that the 2 belongs to the hexyl (as we now do with "2-naphthyl" ), but we already have more such symbols of separation of parts of chemical names t h a n we like and there is a reluctance t o increase their u s e .
SL 2OOF..
CHEMICAL
"Glyodin" has been coined as t h e common (generic) n a m e for the fungicide 2-heptadecyl-2-imidazoline acetate, also k n o w as 2-heptadecylglyoxalidine acetate. It is a light orange, crystalline compound h a v i n g t h e empirical formula C22H44N2O2. T h e term "glyodin" has been approved b y t h e Interdepartmental Committee on Pest Control and accepted b y t h e ACS and other organizations. Glyodin is t h e active ingredient in a commercial preparation sold as Crag Fruit Fungicide 341 (trade-mark of Carbide and Carbon Chemicals C o . ) . AND
ENGINEERING
NEWS
