Obituary pubs.acs.org/crt
a Ph.D. in Chemistry with a dissertation on “The Nitrosative Cleavage of Tertiary Amines” (1963). His further academic career took him to an NIH postdoctoral fellowship with Professor Nelson J. Leonard in 1963, University of Illinois, where he worked on purine chemistry. He accepted, in 1964, at the age of 26 years, a professional position in chemistry at the University of Missouri. He had a long and distinguished career on the faculty at the University of Missouri, rising through the ranks, to become full professor and later H. G. Schlundt Distinguished Professor. After almost 40 years at the University of Missouri, he became Emeritus in 2003. Until lately, as his health allowed, he kept his level of activity, enjoying traveling and scientific productivity. He was a faculty associate and Visiting Scholar in the Department of Medicinal Chemistry, University of Washington, Seattle, WA, the area he had moved to in his retirement. His early work on nitrosative cleavage of tertiary amines eventually toppled a most persistent myth in organic chemistry; chemistry students at that time (and still for a couple of years thereafter) were exposed to the following: “primary amines react with nitrous acid by formation of alcohols, secondary ones form nitrosamines, whereas tertiary amines do not react at all”. The assumed inertness of tertiary amines has even been made the basis of a test for distinguishing them from primary and secondary ones. Dick’s dissertation, published in Journal of the American Chemical Society, 89:5, March 1, 1967, provided the mechanistic basis of nitrosamine formation from tertiary amines by nitrosative dealkylation. Dick reportedly told his advisor after his thesis defense that “nitrosamines were boring compounds without much chemistry and that he probably would never return to this research area.” Fortunately, this prediction did not hold true. In fact, this publication became one of the hallmark discoveries of chemical carcinogenesis. The extremely wide span and biological relevance of this chemistry were gradually explored by Dick and his co-workers, as well as by many fellow scientists throughout the world, inspired by these findings. Among the many significant results of this research, the elucidation of the mechanisms of formation of tobacco-specific nitrosamines, very potent carcinogens arising in part from tertiary amine tobacco constituents like nicotine, may be mentioned. The role of nitrogen oxides in nitrosation reactions in vivo and in the human environment was gradually unveiled by Dick and colleagues working in the field. In the end, this research brought about the elimination, or at least significant reduction, of nitrosamines in consumer goods like cosmetics or personal care items, in metalworking fluids, and in drugs. Dick’s engagement in mitigating human exposure to nitrosamines did not cease until late in his life when he provided essential input into a European Commission document (SCCS Opinion on Nitrosamines and Secondary Amines in Cosmetic Products,
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ith the tragic death of Richard (Dick) Loeppky, the scientific community lost an outstanding scientist and eminent leader in chemical toxicology whose contribution to mechanisms of carcinogenesis by N-nitroso compounds has been essential to many working in the field. Dick passed away Saturday, April 21, 2012. The sad news reached his close friends through his daughter Ann, who, together with her family, provided him with loving care during his last, difficult period of life. In his greetings for the New Year, 2012, he wrote how he enjoyed family and the company of grandkids, after having spent Christmas in the hospital. Slowly recovering, he was firmly looking forward to making progress and appeared to be on the path to full recovery. It is all the more shattering to see him gone. Dick loved science enthusiastically. His outstandingly sharp mind, his extraordinary knowledge, and judgment made him a great scientific peer whose critique and advice were highly rated by his fellows in chemical toxicology. He was extraordinarily supportive with his advice, generously sharing his thoughts and ideas, in discussions with his colleagues, always providing constructive critique and suggestions. Trained as an organic chemist, he left big footprints in chemical carcinogenesis, by the quality of his research, the intellectual clarity of his publications, and the originality of his ideas. What counted perhaps even more was Dick’s engaging personality, his empathy with his scholars and colleagues, and his interest and respect for personal life and professional details that brought him many friends for life. He was a demanding but beloved mentor for undergraduate, doctoral, and postdoctoral fellows, many of whom have reached prominent positions. After graduating from high school, he earned a B.S. in Chemistry at the University of Idaho. During that time, he spent the summers working in a lumber mill. He recalled, “The work was hard and boring, but it paid very well and provided for my college education.” Richard then moved to the University of Michigan for his graduate studies (1959). He received an M.S. in Chemistry (1961), working in the laboratory of Professor Peter A. S. Smith (1963), and earned © 2012 American Chemical Society
Received: May 15, 2012 Accepted: May 15, 2012 Published: May 25, 2012 1155
dx.doi.org/10.1021/tx300219b | Chem. Res. Toxicol. 2012, 25, 1155−1156
Chemical Research in Toxicology
Obituary
2012) in writing since his health status in 2011 did not allow him to travel. Dick’s scientific interests centered around mechanisms of organic chemistry relevant for the biochemistry of nitrosamine carcinogenesis. A major subject has been the mode of action of β-oxidized compounds, where he demonstrated that their metabolic conversion leads to products of α- and βhydroxylation, both forming DNA adducts, making these compounds bidentate carcinogens. Within that field, novel αnitrosamino-aldehydes were synthesized and characterized with respect to their chemical and biological reactivity, including various types of DNA damage. Since he was deeply interested in organic chemistry mechanisms, he also studied reactions of a variety of pharmacologically active molecules under nitrosation conditions, including certain amidines, imidazolines, aziridines, and a spectrum of tertiary amine drug constituents. This research was highly original and provided understanding of the intricate reaction mechanisms and cascades by which N-nitroso compounds can form and react. Again, this knowledge was applied by Dick in creating methods and strategies for blocking nitrosamine formation, an area where he produced a series of publications and patent applications. Dick received wide recognition and many awards in his career. To name but a few, he received National Cancer Institute Merit Awards (1986−1993 and 1994−2000), was on the cover of Cancer Research (September 1989), and received a Fogarty Senior Fellowship (NIH,1993−1994), which allowed him to take a visiting professorship in Kaiserslautern, Germany in the group of G. Eisenbrand. He got the Silver and Gold Outstanding Alumni Award from the University of Idaho (2000) and was named one of the inaugural Fellows of the American Chemical Society in 2009. He was the founding chair of the ACS Division of Chemical Toxicology. He received the ACS Division of Chemical Toxicology Founders’ Award in 2010 and was inducted into the University of Idaho Hall of Fame (2011). Most of all, Dick will be missed for the support he gave to his friends, colleagues, students, and postdoctoral fellows. He was a champion of good science, the one person one hoped to review one's papers or sit in the Study Section when one's grant was under review. He was tough but fair. What else could one ask for?
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dx.doi.org/10.1021/tx300219b | Chem. Res. Toxicol. 2012, 25, 1155−1156
