but also which optical isomer will result. An example is optically active 5,5diphenyl-2-methyl-3,4-cyclopentano1,3,2-oxazaborolidine, which catalyzes reduction by diborane of ketones to enantiomeric secondary alcohols. The ketone oxygen complexes with the boron heteroatom of the chemzyme, and borane complexes with the nitrogen atom next to it. Typical reductions are complete in two minutes at -10 °C with enantiomeric excesses of close to 100%. In lauding his theories of organic synthesis, the Swedish academy meant Corey's technique of retrosynthesis. In this method, chemists begin with the desired molecular structure and use certain rules to work back to possible immediate precursors. Then each such precursor is analyzed in the same way to conceive of precursors two steps back. The result of retrosynthesis is a tree of possible synthetic routes that branches out from the end structure. Chemists choose among them according to feasible reactions and available starting materials. The rules of retrosynthetic analysis begin with cataloging all features
of the end structure with synthetic significance. Such features include chains, rings, branches, functional groups, dissymmetric centers, and the reactivity, sensitivity, and stability of each group. The next step in conceiving possible precursors is to reduce molecular complexity. This involves breaking chains and rings; r e m o v i n g b r a n c h e s , functional groups, and dissymmetric centers; and modifying or removing sites of high reactivity or instability. Retrosynthesis can be reduced to algorithms, and Corey has devised a computer program called LHASA (Logic & Heuristics Applied to Synthetic Analysis) to generate trees of precursor structures. The prostaglandins that the academy considered Corey's most significant synthetic achievements are a family of about 20 potent octylcyclopentylheptanoic acids produced in minute amounts in every cell in the body. Prostaglandins are produced from such fatty acids as arachidonic (5,8,11,14-eicosatetraenoic), which is also t h e s o u r c e of r e l a t e d eicosanoids such as prostacyclins, thromboxanes, and leukotrienes. Stephen Stinson
Dow quarterly earnings halved; others fare better Chemical company earnings reported so far for this year's third quarter lead to the supposition that the quarter will show poorer results at firms heavily tied to downstream petrochemical products, while those with heavy investment in valueadded products will fare better. Earnings for Dow Chemical were about half those of a year ago, for example. But many other firms reporting thus far did better than a year earlier. Dow's earnings for the quarter were $284 million, down 52% from third-quarter 1989. However, sales increased 16% to $4.92 billion, indicating a profit squeeze caused by rising oil prices and declining demand in a slowing economy. Georgia-Gulf, with its heavy dependence on commodity chemicals such as chlor-alkalies, is in the same boat as Dow. Its earnings fell 50% to $23.2 million on a 7% sales decline to $233 million.
Other chemical firms did much better, however. For instance, Rohm & Haas' earnings grew 41% for the third quarter to $45.9 million, on a 10% sales increase to $684 million. The company attributes the earnings gain to a strong North American market, stronger European currencies, and efficient plant operations. W. R. Grace had strong operating results in all business segments, with earnings from the company's operations up 23% to about $45.2 million. This excludes a significant nonrecurring gain in the third quarter of 1989. Sales were up 12% to $1.67 billion. At Imcera (formerly International Minerals), earnings grew 96% to $18 million, with sales up 19% to $376 million. Imcera credits new product introductions, capacity additions, improved operating performance, and higher product margins for the gains. Other companies citing earnings
gains, excluding extraordinary and nonrecurring items, include Loctite, up 22% to $17.6 million; Goodrich, up 29% to $50.6 million; Crompton & Knowles, up 20% to $7.0 million; Morton International, up 30% to $33.7 million; Great Lakes Chemical, up 12% to $17.8 million; Ethyl, up 3% to $56.2 million; and American Cyanamid, up 2% to $52.0 million. William Storck
Physician/lawyer selected to lead FDA David A. Kessler, a physician and a lawyer, was named last week by President Bush as Commissioner of the Food & Drug Administration. Kessler, 39, medical director of the Hospital of Albert Einstein College of Medicine, says he looks "forward to the challenges ahead." Kessler also teaches food and drug law at Columbia University's law school, and has written extensively on FDA issues. From 1981 to 1984, he was consultant to Sen. Orrin G. Hatch (R.-Utah), w h o was then chairman of the Labor & Human Resources Committee. Hatch, in fact, brought Kessler's name to Bush's att e n t i o n . The S e n a t o r b e l i e v e s Kessler "will bring the needed thrust to get FDA going in the direction needed." Perhaps most relevant to Kessler's selection as FDA Commissioner is
Kessler: bring needed thrust to FDA October 22, 1990 C&EN 5
