Mark S. Cushman is an American chemist, whose primary research is in the area of medicinal chemistry. He completed his pre-pharmacy studies at Fresno State College (now California State University, Fresno) in 1965. He then attended the University of California San Francisco (as a University of California Regents Scholar), earning a Pharm.D. in 1969 and a Ph.D. in Medicinal Chemistry in 1973. Thereafter, he performed postdoctoral training in the laboratory of George Büchi, Ph.D., at the Massachusetts Institute of Technology (MIT). There, his research focused on the discovery and development of new synthetic methodologies, [1] and the isolation and structural characterization of mycotoxins from Aspergillus niger. [2] In 1975, he joined the Department of Medicinal Chemistry and Molecular Pharmacology (at the time, Department of Medicinal Chemistry and Pharmacognosy) at Purdue University. From 1983 to 1984, Prof. Cushman was a Senior Fulbright Scholar at Munich Technical University working in the laboratory of Professor Adelbert Bacher. His sabbatical work dealt with the design and synthesis of probes to elucidate key aspects of the biosynthesis of riboflavin (vitamin B2). [3] Currently he holds the rank of Distinguished Professor Emeritus of Medicinal Chemistry at Purdue University. [4] He has mentored 40 graduate students, 59 postdoctoral researchers, and 5 visiting scholars. He has published 348 papers and holds 41 patents. His work has ~17,000 citations with an h-index of 69. His most cited papers had 471, 403, and 299 citations as of August 2021. [4] He has made seminal contributions to the fields of synthetic and medicinal chemistry including the development of new synthetic methodologies, the synthesis of natural products, and the preparation of antivirals, antibacterials, and anticancer agents, and mechanism probes to understand the function of over thirty macromolecular targets. [4] One of his main scientific contributions is the development of the indenoisoquinolines, molecules that inhibit the action of toposiomerase I (Top1) and stabilize the G-quadruplex in the Myc promoter. [5] Three indenoisoquinolines designed and synthesized by his research group at Purdue University [indotecan (LMP 400), indimitecan (LMP 776), and LMP 744] demonstrated potent anticancer activity in vivo and have completed phase I clinical trials at the National Institutes of Health. [6]
Mark Cushman was born on August 20, 1945, in the city of Fresno, California. A main influence during his formative years was his maternal grandfather, Stanley Borleske, who taught engineering and mathematics at Fresno State College. Mr. Borleske also worked as head football, basketball, and baseball coach at Fresno State College. Besides instilling his love for football, his grandfather influenced traits such as coaching/mentoring, hard-work, a special attention to detail, planning, ethics, and love for learning. These attributes have been the hallmarks of Professor Cushman's character. [7]
In the 1970's, while working in the group of Neal Castagnoli, Jr., Ph.D., he reported and studied in detail the condensation of cyclic anhydrides with imines [8] (work that was based on a previous report by Castagnoli [9] ). This reaction is currently known as the Castagnoli-Cushman reaction. One of its first applications was for the preparation of nitrogen analogues of tetrahydrocannabinol, a pharmacologically active natural product isolated from Cannabis sativa. [10] This versatile transformation has been used to generate polysubstituted lactam carboxylic acids and to prepare benzophenanthridine and protoberberine alkaloids, and hundreds of indenoisoquinolines. [11] [12] [13] A general scheme of the Cushman-Castagnoli reaction, applied to the synthesis of a model indenoisoquinoline, is shown to the right. Later, the conditions were optimized and include the formation of an acyl chloride followed by condensation using AlCl3. [14] [15]
Dr. Cushman is the world leader in the design and synthesis of the indenoisoquinolines. [16] These drugs, which were discovered serendipitously during a synthesis of the antileukemic agent nitidine chloride, can eradicate cancer cells. The seminal paper describing the synthesis of the molecules, using the Castagnoli-Cushman Reaction, was published in The Journal of Organic Chemistry. [17] Alternatively, the indenoisoquinolines can be prepared by reacting a benz[d]indeno[1,2-b]pyran-5,11-dione (I) with an amine (II).
Initially, it was discovered the indenoisoquinolines inhibited the action of the topoisomerase I enzyme. [18] [19] Later, it was found these molecules can also affect other targets including the retinoid X receptor (RXR), [20] poly [ADP-ribose] polymerase 1 (PARP-1), [21] topoisomerase II, [22] estrogen receptor, [23] vascular endothelial growth factor-2 (VEGFR-2), [23] hypoxia-inducible factor 1-alpha (HIF-1a), [24] tyrosyl DNA phosphodiesterases (TDP) 1 and 2, and G-quadruplexes. [5]
In addition, the Cushman group and collaborators have reported that indenoisoquinolines could potentially treat other diseases including visceral Leishmaniasis, African trypanosomiasis (sleeping sickness), and Angelman syndrome.
Another main contribution of Mark Cushman and his group deals with the synthesis of various natural products and pharmacologically active synthetic substances. Some of the compounds his group prepared include: the antileukemic agent nitidine chloride (III); [25] corydaline, [26] which possesses antinociceptive and antiallergic activities among others; thalictricavine, [27] an inhibitor of human acetylcholinesterase and butyrylcholinesteras; [28] berlambine; [27] (±)-canadine; (+)-thalictrifoline; [29] cosalane (IV), [30] a molecule that inhibits HIV by acting on various targets; [31] (±) chelidonine, [32] a non-specific cholinesterase inhibitor; ammosamide B (V), [33] a cytotoxic natural product that targets myosin; [34] lavendustin A (VI), [35] a tyrosine kinase inhibitor; [36] and (+)- and (–)-corynoline. [37] [38]
Professor Cushman has received various awards including:
Dr. Cushman served on the Editorial Advisory Board of The Journal of Organic Chemistry (1999–2004). He also served on the Editorial Advisory Board (2005–2010) and as Associate Editor (2012–2020) of The Journal of Medicinal Chemistry. He is a member of the Board of Directors of Gibson Oncology.
In organic chemistry, benzyl is the substituent or molecular fragment possessing the structure R−CH2−C6H5. Benzyl features a benzene ring attached to a methylene group group.
The Wacker process or the Hoechst-Wacker process refers to the oxidation of ethylene to acetaldehyde in the presence of palladium(II) chloride and copper(II) chloride as the catalyst. This chemical reaction was one of the first homogeneous catalysis with organopalladium chemistry applied on an industrial scale.
The Negishi coupling is a widely employed transition metal catalyzed cross-coupling reaction. The reaction couples organic halides or triflates with organozinc compounds, forming carbon-carbon bonds (C-C) in the process. A palladium (0) species is generally utilized as the metal catalyst, though nickel is sometimes used. A variety of nickel catalysts in either Ni0 or NiII oxidation state can be employed in Negishi cross couplings such as Ni(PPh3)4, Ni(acac)2, Ni(COD)2 etc.
Topoisomerase inhibitors are chemical compounds that block the action of topoisomerases, which are broken into two broad subtypes: type I topoisomerases (TopI) and type II topoisomerases (TopII). Topoisomerase plays important roles in cellular reproduction and DNA organization, as they mediate the cleavage of single and double stranded DNA to relax supercoils, untangle catenanes, and condense chromosomes in eukaryotic cells. Topoisomerase inhibitors influence these essential cellular processes. Some topoisomerase inhibitors prevent topoisomerases from performing DNA strand breaks while others, deemed topoisomerase poisons, associate with topoisomerase-DNA complexes and prevent the re-ligation step of the topoisomerase mechanism. These topoisomerase-DNA-inhibitor complexes are cytotoxic agents, as the un-repaired single- and double stranded DNA breaks they cause can lead to apoptosis and cell death. Because of this ability to induce apoptosis, topoisomerase inhibitors have gained interest as therapeutics against infectious and cancerous cells.
sec-Butyllithium is an organometallic compound with the formula CH3CHLiCH2CH3, abbreviated sec-BuLi or s-BuLi. This chiral organolithium reagent is used as a source of sec-butyl carbanion in organic synthesis.
The Achmatowicz reaction, also known as the Achmatowicz rearrangement, is an organic synthesis in which a furan is converted to a dihydropyran. In the original publication by the Polish Chemist Osman Achmatowicz Jr. in 1971 furfuryl alcohol is reacted with bromine in methanol to 2,5-dimethoxy-2,5-dihydrofuran which rearranges to the dihydropyran with dilute sulfuric acid. Additional reaction steps, alcohol protection with methyl orthoformate and boron trifluoride) and then ketone reduction with sodium borohydride produce an intermediate from which many monosaccharides can be synthesised.
In organic chemistry, diazirines are a class of organic molecules consisting of a carbon bound to two nitrogen atoms, which are double-bonded to each other, forming a cyclopropene-like ring, 3H-diazirene. They are isomeric with diazocarbon groups, and like them can serve as precursors for carbenes by loss of a molecule of dinitrogen. For example, irradiation of diazirines with ultraviolet light leads to carbene insertion into various C−H, N−H, and O−H bonds. Hence, diazirines have grown in popularity as small, photo-reactive, crosslinking reagents. They are often used in photoaffinity labeling studies to observe a variety of interactions, including ligand-receptor, ligand-enzyme, protein-protein, and protein-nucleic acid interactions.
Anthony Gerard Martin Barrett FRS, FMedSci is a British chemist, and Sir Derek Barton Professor of Synthesis, Glaxo Professor of Organic Chemistry at Imperial College London. He is Director of the Wolfson Centre for Organic Chemistry in Medical Science. He was elected a fellow of the Royal Society in 1999 and Academy of Medical Sciences in 2003. He obtained a BSc as well as PhD from Imperial College London in 1973 and 1975 respectively.
Lavendamycin is a naturally occurring chemical compound discovered in fermentation broth of the soil bacterium Streptomyces lavendulae. Lavendamycin has antibiotic properties and anti-proliferative effects against several cancer cell lines. The use of lavendamycin as a cytotoxic agent in cancer therapy failed due to poor water solubility and non-specific cytotoxicity. The study of lavendamycin-based analogs designed to overcome these liabilities has been an area of research.
The Davis–Beirut reaction is N,N-bond forming heterocyclization that creates numerous types of 2H-indazoles and indazolones in both acidic and basic conditions The Davis–Beirut reaction is named after Mark Kurth and Makhluf Haddadin's respective universities; University of California, Davis and American University of Beirut, and is appealing because it uses inexpensive starting materials and does not require toxic metals.
David Markham Lemal is the Albert W. Smith Professor of Chemistry Emeritus and Research Professor of Chemistry at Dartmouth College. He received an A.B. degree (summa) from Amherst College in 1955 and a Ph.D. in chemistry from Harvard University in 1959. At Harvard he worked with R. B. Woodward on deoxy sugars and a synthesis of the alkaloid yohimbine.
Peter Wipf is the distinguished university professor of chemistry at the University of Pittsburgh. His research interests focus on the total synthesis of natural products, the discovery of new transformations of strained molecules, and the development of new pharmaceuticals. He is a Fellow of the Royal Society of Chemistry (RSC), the American Association for the Advancement of Science (AAAS), and the American Chemical Society (ACS).
MoOPH, also known as oxodiperoxymolybdenum(pyridine)-(hexamethylphosphoric triamide), is a reagent used in organic synthesis. It contains a molybdenum(VI) center with multiple oxygen ligands, coordinated with pyridine and HMPA ligands. It is an electrophilic source of oxygen that reacts with enolates and related structures, and thus can be used for alpha-hydroxylation of carbonyl-containing compounds. Other reagents used for alpha-hydroxylation via enol or enolate structures include Davis oxaziridine, oxygen, and various peroxyacids. This reagent was first utilized by Edwin Vedejs as an efficient alpha-hydroxylating agent in 1974 and an effective preparative procedure was later published in 1978.
In organic chemistry, the Fujiwara–Moritani reaction is a type of cross coupling reaction where an aromatic C-H bond is directly coupled to an olefinic C-H bond, generating a new C-C bond. This reaction is performed in the presence of a transition metal, typically palladium. The reaction was discovered by Yuzo Fujiwara and Ichiro Moritani in 1967. An external oxidant is required to this reaction to be run catalytically. Thus, this reaction can be classified as a C-H activation reaction, an oxidative Heck reaction, and a C-H olefination. Surprisingly, the Fujiwara–Moritani reaction was discovered before the Heck reaction.
The Riley oxidation is a selenium dioxide-mediated oxidation of methylene groups adjacent to carbonyls. It was first reported by Riley and co-workers in 1932. In the decade that ensued, selenium-mediated oxidation rapidly expanded in use, and in 1939, Guillemonat and co-workers disclosed the selenium dioxide-mediated oxidation of olefins at the allylic position. Today, selenium-dioxide-mediated oxidation of methylene groups to alpha ketones and at the allylic position of olefins is known as the Riley Oxidation.
Clark Landis is an American chemist, whose research focuses on organic and inorganic chemistry. He is currently a Professor of Chemistry at the University of Wisconsin–Madison. He was awarded the ACS Award in Organometallic Chemistry in 2010, and is a fellow of the American Chemical Society and the American Association for the Advancement of Science.
The Mizoroki−Heck coupling of aryl halides and alkenes to form C(sp2)–C(sp2) bonds has become a staple transformation in organic synthesis, owing to its broad functional group compatibility and varied scope. In stark contrast, the palladium-catalyzed reductive Heck reaction has received considerably less attention, despite the fact that early reports of this reaction date back almost half a century. From the perspective of retrosynthetic logic, this transformation is highly enabling because it can forge alkyl–aryl linkages from widely available alkenes, rather than from the less accessible and/or more expensive alkyl halide or organometallic C(sp3) synthons that are needed in a classical aryl/alkyl cross-coupling.
The Stahl oxidation is a copper-catalyzed aerobic oxidation of primary and secondary alcohols to aldehydes and ketones. Known for its high selectivity and mild reaction conditions, the Stahl oxidation offers several advantages over classical alcohol oxidations.
T.V. (Babu) RajanBabu is an organic chemist who holds the position of Distinguished Professor of Chemistry in the College of Arts and Sciences at the Ohio State University. His laboratory traditionally focuses on developing transition metal-catalyzed reactions. RajanBabu is known for helping develop the Nugent-RajanBabu reagent, a chemical reagent used in synthetic organic chemistry as a single electron reductant.
Kathlyn Ann Parker is a chemist known for her work on synthesis of compounds, especially organic compounds with biological roles. She is an elected fellow of the American Chemical Society and a recipient of the Garvan–Olin Medal in chemistry.
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