DED UN 18 O 98 F yyyy N yyyy Y O T R E I T H C E O yyyyN A E S S S L T A E A C R C I yyyyN S M S E E H C C T N IO A May 2003 Vol. LXXXI, No. 9 yyyyC N • AMERI Monthly Meeting Education Night at B.U. Guy Crosby speaks on Chemistry of Nutrition Election 2003 Election of candidates for 2004 Book Review Quantum Leaps in the Wrong Direction, by C. M. Wynn and A. W. Wiggins Historical Note Edward Frankland’s Crusade for Clean Water in the 19th Century template group. If this were true, then this end, a simple molecular modeling Meeting virtually any ring system which ful- exercise was undertaken to compare filled this requirement would lead to a the differences between our best com- series of potent inhibitors pound and those reported by Merck. Report We selected the 1H-pyrrole ring The simple overlay of these molecules From the April 10, 2003 Esselen system as our starting template to test revealed the presence of a methyl Award Address this hypothesis, primarily because group in the Merck compound in a these could readily be prepared from region of space not occupied by our The Discovery And 1,4-diketones through the classical inhibitors. Development Of Lipitor‚ Paal-Knorr condensation and these 1,4- To determine the importance of (Atorvastatin Calcium) diketones, in turn, were potentially occupying this space, bromine and available possessing a wide variety of chlorines were introduced into the 3- Bruce D. Roth, Department of Chem- 1- and 4-substituents employing the and 4-positions of our most potent ana- istry, Pfizer Global Research and thiazolium salt chemistry developed by log. After testing the ability of these Development, Ann Arbor Laboratories Stetter. compounds to inhibit rat-liver HMGR, Despite decades of research, coronary In practice, this scheme proved we were gratified to find that both heart disease is still the number one highly effective and a large number of compounds possessed inhibitory cause of death in the United States and 1,2,5-trisubstituted pyrroles were pre- potencies comparable to the fungal in many western societies. Because of pared. These could be converted in metabolites the importance of this public health several synthetic steps to the target 4- Although initially we were excited issue, the search for drugs to lower lev- hydroxy-pyranones as racemic mix- by this finding, the 3,4-dibromo analog els of total and low-density lipoprotein tures of the 4R, 6R and 4S, 6S was taken into early preclinical devel- cholesterol has been the focus of con- stereoisomers. These were then ring- opment and rapidly found to display siderable research over the past four opened by base hydrolysis to provide considerable toxicity. As it turned out, decades. A major chapter in this story the biologically active dihydroxyacids. much of the toxicology had been was the search for potent and effica- Using this chemistry we next pre- observed by others and was found to cious inhibitors of the enzyme HMG- pared a series of approximately thirty be specific to rodents or was derived CoA reductase (HMGRI), the 2,5-disubstituted analogs possessing a from exaggerated pharmacology at rate-limiting enzyme in cholesterol range of substituted aromatic, cyclic, high dosage levels and was most biosynthesis especially during the branched and straight-chain aliphatic severe with very bioavailable 1970s and 1980s. Building on the dis- groups to define the optimal sub- inhibitors which achieved high plasma covery of the fungal metabolite- stituents at the 2- and 5-positions. and tissue concentrations. Once again, derived inhibitors, mevastatin, The conclusion from this exercise we were faced with a decision point in lovastatin, pravastatin and simvastatin, was that the distance across the pyrrole the pyrrole series. Since we did not during the late 1970s and early 1980s, ring from the tip of the 2-substituent to know whether the toxicity observed a number of totally synthetic the tip of the 5-substituent could be no was related to the mechanism of inhibitors, including atorvastatin cal- longer than 10 angstroms with the size action, the pyrrole series or the pres- cium were discovered and developed. of the 2-substituent being no more than ence of the bromines in the 3- and 4- The first indication that the com- 5.9 angstroms and the 5-substituent positions, rather than abandoning the plex hexahydronaphthalene portion of being no more than 3.3 angstroms. pyrrole series, a two pronged approach the fungal metabolites could be Further refinement of this analysis was taken of both looking for alterna- replaced with a simpler ring system revealed that best potency was con- tive series and synthesizing 3,4-non- without loss of biological activity tained in the compound possessing a 4- halogen-substituted pyrroles in the appeared in a patent application, then fluorophenyl in the 2-position and an hope that these compounds would in publication form, from the Merck, isopropyl in the 5-position of the pyr- retain activity, but lack toxicity . Sharpe and Dohme Research Labs. In role ring. Unfortunately, this com- Unfortunately, the requirement for a this disclosure, it was revealed that pound still possessed only one-tenth of penta-substituted pyrrole also required ortho-biphenyl containing 3,5-dihy- the inhibitory potency of mevastatin. the development of an entirely new droxy-6-heptenoic acids and their lac- Taking into account the likely sce- synthetic route to effectively develop tones were equipotent to the fungal nario that all of the biological activity the SAR at the 3- and 4-positions, metabolites at inhibiting HMGR in was contained in one stereoisomer, we since the existing route was limited vitro. This disclosure led to the were still considerably short of the tar- only to those substituents that could be hypothesis that the key requirements get potency and had come to the limit introduced by electrophilic substitu- for potent inhibition of HMGR were a of what could be accomplished using tion. mevalonolactone/3,5-dihydroxy-hep- the current synthetic route. In these A possible solution was presented tanoic or-6-heptenoic acid moiety and circumstances, the options are to find through the 3+2 cycloaddition of a large lipophilic group held in the cor- alternate series or to attempt to ascer- azlactones and acetylenes pioneered by tain the source of the deficiency. To rect spatial relationship by a spacer or continued on page 4 2 The Nucleus May 2003 Samuel P. Kounaves The Northeastern Section of the American Chemical Society, Inc. Contents Office: Marilou Cashman, 23 Cottage St., Natick, MA 01760. 1-800-872-2054 (Voice or FAX) or 508-653-6329. Meeting Report 2 e-mail: [email protected] ________________________________________ Any Section business may be conducted Bruce D. Roth’s Esselen Award Address at the April 10, 2003 meeting via the business office above. NESACS Homepage: http://www.NESACS.org Monthly Meeting: Education Night _________________________5 Samuel P. Kounaves, Webmaster Awards; Address by Guy A. Crosby: “Recent Developments in the Chemistry of Washington, D.C. ACS Hotline: 1-800-227-5558 Nutrition and Their Impact on Human Health” Officers 2003 Chair: ACS Short Course ______________________________________6 John L. Neumeyer Harvard Medical School/McLean Hospital LC/MS: Fundamentals and Applications; May 19-20 at Northeastern University 115 Mill St., Belmont, MA 02478 617-855-3388; [email protected] Weinberg Memorial Lecture ______________________________7 Chair-Elect: Jean A. Fuller-Stanley Daniel Von Hoff, M.D. speaks on “Current Approaches to Phase I Chemical Chemistry Department, Wellesley College Trials” Wellesley, MA 02481-8203 781-283-3224; [email protected] Immediate Past Chair: Election of Candidates for 2004 __________________________8 Morton Z, Hoffman Biographies and statements of candidates for office in 2004 Chemistry Department, Boston University Boston, MA 02215-2507 617-353-2494; [email protected] Book Review _________________________________________23 Secretary: “Quantum Leaps In The Wrong Direction” by C.M. Wynn and A.W. Wiggins, Michael Singer Sigma RBI reviewed by Dennis J. Sardella 3 Strathmore Rd. Natick, MA 01760-2447 508-651-8151x291 Historical Note _______________________________________25 [email protected] “Edward Frankland’s Crusade for Clean Water” by Sharon Bertsch McGrayne Treasurer: James Piper 19 Mill Rd., Harvard, MA 01451 Cover: Guy A. Crosby, May speaker 978-456-3155 [email protected] Auditor: Deadlines: Summer Issue: June 13, 2003 Anthony Rosner September issue: July 18, 2003 Archivist: Myron Simon 20 Somerset Rd. Newton, MA 02465; 617-332-5273 [email protected] Trustees: Joseph A. Lima, Esther A.H. Hopkins, Michael E. Strem, Councilors: Alternate Councilors: Term Ends 12/31/2003 Term Ends 12 /31/2003 The Nucleus is distributed to the members of the Northeastern Section of the American Chemical Catherine E. Costello Wallace Gleekman Society, to the secretaries of the Local Sections, and to editors of all local A.C.S. Section publications. William Klemperer Arno H.A. Heyn Forms close for advertising on the 1st of the month of the preceding issue. Text must be received by the Dorothy J. Phillips Howard R. Mayne editor six weeks before the date of issue. Barbara Wood Alfred Viola Editor: Arno Heyn, 21 Alexander Rd., Newton, MA 02461, Term Ends 12/31/2004 Term Ends 12/31/2004 Tel: 617-969-5712, FAX: 617-527-2032; e-mail: [email protected] Thomas R. Gilbert Timothy B. Frigo Patricia H. Hamm Donald O. Rickter Associate Editors: Myron S. Simon, 20 Somerset Rd., W. Newton, MA 02465, Tel: 617-332-5273 Michael J. Hearn Lawrence T. Scott Mukund S. Chorghade, 14 Carlson Circle, Natick, MA 01760: Arlene W. Light Derk A. Wierda [email protected] Term Ends 12/31/2005 Term Ends 12/31/2005 Board of Publications: Marietta H.