The Additivity Relation in A Values

Thus for the case shown (Fig. 2.64), the calculated curve was made by adding the six experimental component CD curves (B and C represent, respectively, bromobenzoate and methoxycinnamate) 2B/3B, 4C/6C, 2B/4C, 3B/4C, and 3B/6C. Excellent agreement is seen throughout the entire CD range. This additiv- 

We have attempted to cover the current status of isolation techniques and various spectroscopic methods used in modern natural products chemistry. Not surprisingly, the field is advancing very rapidly, and this article is bound to become rather obsolete in the not too distant future. However, it may serve as a convenient reference. 

Quite a few of the techniques described are not routine, and even if the results are published in papers or depicted in figures, they are frequently the outcome of many frustrating attempts. 

As techniques become more sophisticated, it becomes increasingly difficult to maintain each instrument in top condition. Despite this unavoidable difficulty, and despite the nonroutine nature of some measurements, it is important to know what can be achieved by present-day techniques. We hope that this article may serve to present an overview of modern techniques. 

1 Ahmad V U, Najmus-Saquib Q, Usmaighani K, Fochs W, Voelter W 1980 New terpenoid from Primula denticulata. Z Naturforsch 35b 511-512 

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