Mesyloxy-group migration as the stereoselective preparation method of various functionalized olefins and its reaction mechanism

Synthesis and Biological Evaluation of Novel 3'-Difluorovinyl Taxoids

A series of 3'-difluorovinyl taxoids with C10 modifications, as well as those with C2 and C10 modifications, were strategically designed to block the metabolism by cytochrome P-450 3A4 enzyme and synthesized. These novel difluorovinyl taxoids were evaluated for their cytotoxicity against drug-sensitive human breast (MCF7), multidrug-resistant (MDR) human ovarian (NCI/ADR), human colon (HT-29) and human pancreatic (PANC-1) cancer cell lines. 3'-Difluorovinyl taxoids exhibit several to 16 times better activity against MCF7, HT-29 and PANC-1 cell lines and up to three orders of magnitude higher potency against NCI/ADR cell line as compared to paclitaxel. Structure-activity relationship study shows the critical importance of the C2 modifications on the activity against MDR cancer cell line, while the C10 modifications have a rather minor effect on the potency with some exceptions. The effect of the C2 modifications on potency against MCF7 cell line increases in the following order: H < F < Cl Collapse

Key Words

• anticancer agent
• taxoid
• fluoro-taxoid
• β-lactam synthon method
• difluorovinyl
• baccatin
• structure-activity relationship
• microtubules

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Grants

• R01 CA077263 NCI NIH HHS
• R01 CA083185 NCI NIH HHS
• R01 CA103314 NCI NIH HHS

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Affiliation(s)

Larissa Kuznetsova Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400
Liang Sun Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400
Jin Chen Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400
Xianrui Zhao Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400
Joshua Seitz Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400
Manisha Das Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400
Yuan Li Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400
Jean M. Veith Department of Experimental Therapeutics, Grace Cancer Drug Center, Roswell Park Memorial Institute, Elm and Carlton Streets, Buffalo, New York, 14263
Paula Pera Department of Experimental Therapeutics, Grace Cancer Drug Center, Roswell Park Memorial Institute, Elm and Carlton Streets, Buffalo, New York, 14263
Ralph J. Bernacki Department of Experimental Therapeutics, Grace Cancer Drug Center, Roswell Park Memorial Institute, Elm and Carlton Streets, Buffalo, New York, 14263
Shujun Xia Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
Susan B. Horwitz Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
Iwao Ojima Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400 Institute of Chemical Biology & Drug Discovery, State University of New York at Stony Brook, Stony Brook, NY 11794-3400

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New preparation and synthetic reactions of 3,3,3-trifluoropropynyllithium, -borate and -stannane: facile synthesis of trifluoromethylated allenes, arylacetylenes and enynes

Background: Since trifluoromethyl-containing compounds have found diverse applications in the fields of pharmaceuticals and agrochemicals, facile and selective synthetic methods for trifluoromethyl-substituted compounds are an essential tool for advanced medicinal chemistry. Now that diverse synthetic transformations of carbon–carbon triple bonds are available, 3,3,3-trifluoropropynyl-substituted compounds serve as versatile building blocks for target molecules containing trifluoromethyl groups. Thus, novel synthetic methods and reagents for incorporation of a 3,3,3-trifluoropropynyl group into an organic compound have been the major concern in exploration and modification of fluorine-based biologically active substances. Results & discussion: We report a preparative method of 3,3,3-trifluoropropynyllithium and its reaction with electrophiles including aldehydes, ketones, trimethoxyborane, chlorosilanes and chlorostannanes in detail. Palladium-catalyzed synthetic reactions of the carbonyl adducts and the trifluoromethyl-containing metalloid reagents are also demonstrated, which provide simple synthetic methods of trifluoromethylated allenes, arylacetylenes and enynes. The synthetic transformations presented here expand the repertoire of trifluoromethylated compounds available for medicinal scientists and contribute to the advance of future medicinal chemistry.

Regio- and stereoselective reactions of gem-difluorinated vinyloxiranes with heteronucleophiles

[Reaction: see text]. Regio- and stereoselectivity in reactions of gem-difluorinated vinyloxiranes with heteronucleophiles were successfully controlled. Halogen atoms were introduced regioselectively at the allylic epoxide carbon with an inversion in stereochemistry using MgBr2*Et2O or Li2CuCl4 to produce anti-vic-halohydrine. The other diastereomers were obtained selectively using LiBr/AcOH or BCl3, and SN2' type products were formed selectively with excellent E preference by changing the reaction temperature. Moreover, a further investigation led us to find that a regio- and stereoselective SN2' addition of several Brnsted acids was dependent on the pKa values of the acids. Under strong acidic conditions, we exclusively obtained E allylic alcohols.

A unique catalyst effects the rapid room-temperature cross-coupling of organozinc reagents with carboxylic acid fluorides, chlorides, anhydrides, and thioesters

We have identified a catalyst capable of effecting the rapid, room-temperature cross-coupling between acid fluorides and diorganozinc reagents. The use of acid fluorides as electrophilic partners allows this reaction to tolerate epimerizable functionality as well as beta leaving groups. The same catalyst is also capable of cross-coupling acid chlorides, acyl cyanides, anhydrides, thioesters, and pyridyl esters. Noteworthy is the ability of the reaction to successfully transfer both groups from the organometalic fragment.