59891-97-3Relevant academic research and scientific papers
Decarboxylative cross-nucleophile coupling via ligand-to-metal charge transfer photoexcitation of Cu(ii) carboxylates
Li, Qi Yukki,Gockel, Samuel N.,Lutovsky, Grace A.,DeGlopper, Kimberly S.,Baldwin, Neil J.,Bundesmann, Mark W.,Tucker, Joseph W.,Bagley, Scott W.,Yoon, Tehshik P.
, p. 94 - 99 (2022/01/11)
Reactions that enable carbon–nitrogen, carbon–oxygen and carbon–carbon bond formation lie at the heart of synthetic chemistry. However, substrate prefunctionalization is often needed to effect such transformations without forcing reaction conditions. The development of direct coupling methods for abundant feedstock chemicals is therefore highly desirable for the rapid construction of complex molecular scaffolds. Here we report a copper-mediated, net-oxidative decarboxylative coupling of carboxylic acids with diverse nucleophiles under visible-light irradiation. Preliminary mechanistic studies suggest that the relevant chromophore in this reaction is a Cu(ii) carboxylate species assembled in situ. We propose that visible-light excitation to a ligand-to-metal charge transfer (LMCT) state results in a radical decarboxylation process that initiates the oxidative cross-coupling. The reaction is applicable to a wide variety of coupling partners, including complex drug molecules, suggesting that this strategy for cross-nucleophile coupling would facilitate rapid compound library synthesis for the discovery of new pharmaceutical agents. [Figure not available: see fulltext.].
TRIAZOLE COMPOUNDS AS T-TYPE CALCIUM CHANNEL BLOCKERS
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Page/Page column 48, (2016/04/09)
The invention relates to compounds of formula (I) wherein X, Y, R1, R2, (R4)n, and (R5)m are as defined in the description, and to pharmaceutically acceptable salts of such compounds. These compounds are useful as calcium T-channel blockers.
PYRAZOLE COMPOUNDS AND THEIR USE AS T-TYPE CALCIUM CHANNEL BLOCKERS
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Page/Page column 93, (2015/12/24)
The invention relates to compounds of formula (I) Formula (I) wherein X, Y, R1, R2, (R4)n, and (R5)m are as defined in the description, and to pharmaceutically acceptable salts of such compounds. These compounds are useful as calcium T-channel blockers.
Tri-n-butylstannyl chloride-sodium cyanoborohydride mediated regioselective reductive demethoxylation of alkyl methyl ketals
Srikrishna,Viswajanani
, p. 621 - 625 (2007/10/03)
A regioselective reductive demethoxylation of alkyl methyl ketals employing sodium cyanoborohydride in the presence of a catalytic amount of tri-n-butyltin chloride as Lewis acid is described.
Pyrylium salt promoted substitution reactions of acetals with various silylated nucleophiles
Kamata, Masaki,Nagai, Satoshi,Kato, Mitsuaki,Hasegawa, Eietsu
, p. 7779 - 7782 (2007/10/03)
Catalytic amounts of triarylpyrylium salts photochemically and thermally promoted the substitution reactions of dimethyl acetals with silylated nucleophiles.
The Mechanism of RuO4-Mediated Oxidations of Ethers: Isotope Effects, Solvent Effects and Substituent Effects
Bakke, Jan M.,Froehaug, Astrid E.
, p. 615 - 622 (2007/10/02)
The mechanism of the RuO4-mediated oxidation of ethers to esters has been investigated.Oxidation of cyclopropylmethyl methyl ether gave methyl cyclopropanecarboxylate.No rearranged products were observed.On RuO4 oxidation of benzyl methyl ether and p-methoxybenzyl methyl ether in CCl4 with NaIO4 as stoichiometric oxidant, no chlorinated products were observed.A series of 4-substituted benzyl methyl ethers was oxidized with RuO4-NaIO4.A correlation of the rate of the reaction with Hammett ?-values gave a ρ of -1.7, indicating only a moderate charge separation in the transition state (TS).Benzyl methyl ether (1) was oxidized in a series of acetone-water mixtures.From these experiments, a Grunwald-Winstein m-value of 0.11 was obtained, indicating a non-polar TS for the reaction.PhCHDOCH3 (2) and PhCD2OCH3 (3) were oxidized and two deuterium isotipe effects, one of 6.1+/-0.4 and another of 1.3+/-0.1 were obtained.If one assumes a one-step reaction mechanism, the value of 1.3 would be a large α-secondary isotope effect, indicating a change in the hybridization of the benzylic carbon during the reaction. α-Methylbenzyl methyl ether (4) was oxidized at a seventh of the rate of 1, despite the fact that 4 would have given a more stable carbocation than 1.These conflicting pieces of evidence are difficult to rationalise with a hydride or hydrogen abstraction mechanism.Instead it is proposed that the reaction proceeds by either a concerted reaction or by a reversible oxidative addition of the ether to RuO4 followed by a slow concerted step to give the product.
A mild and simple procedure for the reductive cleavage of acetals and ketals
Srikrishna, Adusumilli,Viswajanani, Ranganathan
, p. 3339 - 3344 (2007/10/02)
A convenient, mild and simple procedure, employing sodium cyanoborohydride in the presence of either catalytic or stoichiometric amount of boron trifluoride etherate in dry THF, for the reductive cleavage of the acetals and ketals is described.
