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Showing papers in "Journal of the American Chemical Society in 1971"



Journal ArticleDOI
TL;DR: The use of modified boron hydrides as selective reducing agents for organic functional g roups has been studied extensively as discussed by the authors, with a focus on reducing a wide variety of organic functional groups with remarkable selectivity.
Abstract: Sodium cyanohydridoborate (NaBH3CN) reduces a wide variety of organic functional groups with remarkable selectivity. The reduction of aldehydes and ketones is p H dependent, the reaction proceeding readily a t pH 3-4. Oximes a re smoothly reduced to alkylhydroxylamines and enamines are reduced to amines under acid catalysis. Reaction of a n aldehyde or ketone with ammonia, primary amine, or secondary amine a t p H -7 i n the presence of BHaCNleads t o primary, secondary, or tertiary amines, respectively, uia reductive amination of the carbonyl group. Reaction of substituted pyruvic acids with ammonia and BH3CNaffords an excellent method for the synthesis of amino acids; l5N labeling can be accomplished by using I5NH3. The hydrogens of BHICNcan be readily exchanged for either deuterium or tritium, thus permitting the synthesis of deuteriumor tritiumlabeled alcohols, amines, and amino acids. onsiderable attention has been devo ted t o t h e The earlier d iscovery o f the reduc ing p o w e r 4 and t h e acid stability5 of l i t h ium cyanohydr idobora t e encourstudy of modified boron hydrides as selective reducing agents for organic functional g roups . 2.3 2127 (1962); (c) R. Paul and N . Joseph, Bull. SOC. Chem. Fr., 550 (1952); (d) H. C. Brown and E. J. Mead, J . Amer. Chem. SOC., 75, 6263 (1953). (3) (a) H. Noth and H. Beyer, Chem. Ber., 93, 1078 (1960); (b) J. H. Billman and J. W. McDowell, J . Org. Chem., 26, 1437 (1961); (C) s. s. White, Jr., and H. C. Kelly, J . Amer. Chem. Soc., 92, 4203 (1970). and references therein. C (1) (a) Alfred P. Sloan Foundation Fellow; (b) National Institutes of Health Predoctoral Fellow, 1968-1970. Taken in part from the Ph.D. Thesis of H. D. D., University of Minnesota, 1970. (2) (a) H. C. Brown and B. C. Subba Rao, J . Amer. Chem. SOC., 78, 2582 (1956); (b) G. R. Pettit and D. M. Piatak, J . Org. Chem., 27, (4) R. F. Borch and H. D. Durst, ibid., 91, 3996 (1969). Borch, Bernstein, Durst Cyanohydridoborate Anion

1,746 citations





Journal ArticleDOI
TL;DR: Dr Alfred S. Ketcham, who assumed his new duties Sept. 1, is a specialist in surgical treatment for cancer, with emphasis on disease of the head and neck area and has developed a program of research on the problems of ex­ perimental and clinical metastasis, or spread, of cancer.
Abstract: Dr. Alfred S. Ketcham was named Clinical Director of the National Cancer Institute. His ap­ pointment was announced by Dr. Carl G. Baker, NCI Director. Dr. Ketcham, who assumed his new duties Sept. 1, is a specialist in surgical treatment for cancer, with emphasis on disease of the head and neck area. He has developed a program of research on the problems of ex­ perimental and clinical metastasis, or spread, of cancer. He also directed research which demonstrated the ineffectiveness of the laser beam as a surgical tool in cancer therapy. Dr. Ketcham received his B.S. degree from Hobart College in 1945, and his M.D. degree from the University of Roch ester School of Medicine in 1949. His internship was served at the Na­ tional Naval Medical Center in Bethesda. He completed surgical training

586 citations












Journal ArticleDOI
TL;DR: The isolation and elucidation of the structures of AMetrahydrocannabinol (A^THC), cannabigerol, cannabichromene, and cannabicyclol are described and a facile conversion of cannabidiol into A'-THC takes place on treatment with boron trifluoride etherate.
Abstract: The isolation and elucidation of the structures of AMetrahydrocannabinol (A^THC), cannabigerol, cannabichromene, and cannabicyclol are described. A facile conversion of cannabidiol into A'-THC takes place on treatment with boron trifluoride etherate. The absolute configuration of the chiral centers at C-3 and C-4 of A'-THC is established as R. T resin of the female Cannabis sativa L. plant has been used as a medicine and a psychotomimetic drug since ancient times. Cannabis preparations were known to the Assyrians, Scythians, ancient Chinese, Indians, and Persians. More recently, increased consumption of either the resin (hashish) or the whole flowering top (marihuana) has caused worldwide social, legal, and medical problems. The chemistry of the constituents of Cannabis has been the subject of numerous publications since the middle of the last century. Due mainly to the masterly investigations of Cahn, Adams, Bergel, and Todd substantial progress was made in this field. However, until 1963, when the structure of cannabidiol (Ia) was elucidated, the only cannabinoid with fully known constitution was the inactive cannabinol (II); the active constituent had not been isolated in pure form, its structure was not fully known, and it was unavailable from either a natural or a synthetic source. The reason for the slow progress is to be found in the lack of suitable separative and analytical techniques in the thirties and early forties, when the important work in Urbana and Cambridge took place. As reproducible pharmacological and clinical investigations can only be undertaken with well-defined materials, this incomplete chemical evaluation of marihuana resulted in an almost total absence of fundamental experimental work on the biological aspects of the Cannabis problem. This lack of data on the pharmacological effects has had, in turn, serious social repercussions in the present wave of marihuana use. In a number of communications we reported the isolation, structure elucidation, and absolute configuration of some neutral cannabinoids, including the major active constituent, A ^tetrahydrocannabinol (1) R. J. Bouquet [Bull Narcotics, 3 (3), 22 (1951), and references cited therein] describes in fascinating detail the history of Cannabis use and the various preparations and modes of consumption in different parts of the world. (2) Reviews: R. Mechoulam and Y. Gaoni, Fortschr. Chem. Org. Naturst., 25, 174 (1967); R. Mechoulam, Science, 168, 1159 (1970). (3) R. S. Cahn, J. Chem. Soc, 1400 (1933). (4) R. Adams, Harvey Led., 37, 168 (1942). (5) F. Bergel and K. Vogele, Justus Liebigs Ann. Chem., 493, 250 (1932). (6) A. R. Todd, Experientia, 2, 55 (1946). (7) R. Mechoulam and Y. Shvo, Tetrahedron, 19, 2073 (1963). (8) (a) Y. Gaoni and R. Mechoulam, Proc. Chem. Soc, 82 (1964); (b) Y. Gaoni and R. Mechoulam, J. Amer. Chem. Soc, 86, 1646 (1964); (c) Y. Gaoni and R. Mechoulam, Chem. Commun., 20 (1966); (d) R. Mechoulam and Y. Gaoni, Tetrahedron Lett., 1109 (1967). (A'-THC). We wish to describe now the full details of this research. Previous work indicated that the active constituent(s) were found in the petroleum ether extract of hashish. We were able to confirm and extend this observation. Benzene and methanol extracts from hashish, which had previously been repeatedly extracted with petroleum ether, were found to be inactive when tested in rhesus monkeys. Hence we concentrated on the petroleum ether fraction, which was separated into neutral and acidic components. The acid fraction was inactive. The following compounds and mixtures were isolated from the active, neutral fraction by repeated chromatography on Florisil or acid-washed alumina, and alumina containing 12% silver nitrate (in order of increasing polarity): (1) a mixture of waxy, noncannabinoid materials; (2) cannabicyclol (III); (3) cannabidiol (Ia); (4) A-THC (IVa); (5) cannabinol (II); (6) cannabichromene (Va); (7) cannabigerol (VI); and (8) polar constituents and polymers. The yields of cannabinoids are indicated in Table I. Table I. Content in Hashish.\" Rs Values (tic), and Retention Times (vpc) of Some Natural Neutral Cannabinoids











Journal ArticleDOI
TL;DR: Among the lower forms of life, even more than among the large species of animals and plants, life inhibits life.
Abstract: Among the lower forms of life, even more than among the large species of animals and plants, life inhibits life.