21205-06-1Relevant academic research and scientific papers
Pd-Catalysed carbonylative Suzuki-Miyaura cross-couplings using Fe(CO)5under mild conditions: generation of a highly active, recyclable and scalable ‘Pd-Fe’ nanocatalyst
Zhu, Zhuangli,Wang, Zhenhua,Jian, Yajun,Sun, Huaming,Zhang, Guofang,Lynam, Jason M.,McElroy, C. Robert,Burden, Thomas J.,Inight, Rebecca L.,Fairlamb, Ian J. S.,Zhang, Weiqiang,Gao, Ziwei
, p. 920 - 926 (2021)
The dual function and role of iron(0) pentacarbonyl [Fe(CO)5] has been identified in gaseous CO-free carbonylative Suzuki-Miyaura cross-couplings, in which Fe(CO)5supplied COin situ, leading to the propagation of catalytically active Pd-Fe nanoparticles. Compared with typical carbonylative reaction conditions, CO gas (at high pressures), specialised exogenous ligands and inert reaction conditions were avoided. Our developed reaction conditions are mild, do not require specialised CO high pressure equipment, and exhibit wide functional group tolerance, giving a library of biaryl ketones in good yields.
DABCO-promoted photocatalytic C-H functionalization of aldehydes
Cardozo, Thiago Messias,Da Silva Santos, Bruno Maia,Finelli, Fernanda Gadini,de Souza, Cauê Paula,dos Santos Dupim, Mariana
supporting information, p. 2959 - 2967 (2022/01/12)
Herein we present a direct application of DABCO, an inexpensive and broadly accessible organic base, as a hydrogen atom transfer (HAT) abstractor in a photocatalytic strategy for aldehyde C-H activation. The acyl radicals generated in this step were arylated with aryl bromides through a well stablished nickel cross-coupling methodology, leading to a variety of interesting aryl ketones in good yields. We also performed computational calculations to shine light in the HAT step energetics and determined an optimized geometry for the transition state, showing that the hydrogen atom transfer between aldehydes and DABCO is a mildly endergonic, yet sufficiently fast step. The same calculations were performed with quinuclidine, for comparison of both catalysts and the differences are discussed.
Visible-Light-Driven Oxidative Cleavage of Alkenes Using Water-Soluble CdSe Quantum Dots
Li, Jianing,Zhao, Jingnan,Ma, Cunfei,Yu, Zongyi,Zhu, Hongfei,Yun, Lei,Meng, Qingwei
, p. 4985 - 4992 (2021/10/16)
The oxidative cleavage of C=C bonds is an important chemical reaction, which is a popular reaction in the photocatalytic field. However, high catalyst-loading and low turnover number (TON) are general shortcomings in reported visible-light-driven reactions. Herein, the direct oxidative cleavage of C=C bonds through water-soluble CdSe quantum dots (QDs) is described under visible-light irradiation at room temperature with high TON (up to 3.7×104). Under the same conditions, water-soluble CdSe QDs could also oxidize sulfides to sulfoxides with 51–84 % yields and TONs up to 3.4×104. The key features of this photocatalytic protocol include high TONs, wide substrates scope, low catalyst loadings, simple and mild reaction conditions, and molecular O2 as the oxidant.
Decarboxylation with Carbon Monoxide: The Direct Conversion of Carboxylic Acids into Potent Acid Triflate Electrophiles
Kinney, R. Garrison,Arndtsen, Bruce A.
supporting information, p. 5085 - 5089 (2019/04/01)
We report a new strategy for the conversion of carboxylic acids into potent acid triflate electrophiles. The reaction involves oxidative carbonylation of carboxylic acids with I2 in the presence of AgOTf, and is postulated to proceed via acyl hypoiodites that react with CO to form acid triflates. Coupling this chemistry with subsequent trapping with arenes offers a mild, room temperature approach to generate ketones directly from broadly available carboxylic acids without the use of corrosive and reactive Lewis or Bronsted acid additives, and instead from compounds that are readily available, stable, and functional group compatible.
Highly atom-economic, catalyst- and solvent-free oxidation of sulfides into sulfones using 30% aqueous H2O2
Jereb, Marjan
, p. 3047 - 3052,6 (2020/09/16)
Highly atom-efficient oxidation of sulfides into sulfones under solvent- and catalyst-free reaction conditions using a 30% aqueous solution of H 2O2 at 75 °C is reported. A structurally diverse set of phenyl alkyl-, phenyl benzyl-, benzyl alkyl-, dialkyl-, heteroaryl alkyl- and cyclic sulfides were transformed into sulfones regardless of the aggregate state and electronic nature of the substituents. In spite of the heterogeneous reaction mixtures throughout the work, no difficulties with stirring and reaction progress were noted. In numerous cases, only 10 mol% excess of H 2O2 was used, thus contributing considerably to the high atom economy of the process. Some solid substrates required a variable excess of hydrogen peroxide; however, the reactions were performed strictly without organic solvents. The transformation was demonstrated to be amenable for scale-up with both liquid and solid sulfides. In addition, isolation and purification of the crude products can be simply done with only filtration and crystallization.
Synthesis and biological evaluation of acyclic triaryl (Z)-olefins possessing a 3,5-di-tert-butyl-4-hydroxyphenyl pharmacophore: Dual inhibitors of cyclooxygenases and lipoxygenases
Moreau, Anne,Praveen Rao,Knaus, Edward E.
, p. 5340 - 5350 (2008/02/07)
A new class of regioisomeric acyclic triaryl (Z)-olefins possessing a 3,5-di-tert-butyl-4-hydroxyphenyl (DTBHP) 5-lipoxygenase (5-LOX) pharmacophore that is vicinal to a para-methanesulfonylphenyl cyclooxygenase-2 (COX-2) pharmacophore were designed for evaluation as selective COX-2 and/or 5-LOX inhibitors. The target compounds were synthesized via a highly stereoselective McMurry olefination cross-coupling reaction. This key synthetic step afforded a (Z):(E) olefinic mixture with a predominance for the (Z)-olefin stereoisomer. Structure-activity studies for the (Z)-1-(3,5-di-tert-butyl-4-hydroxyphenyl)-2-(4-methanesulfonylphenyl)-1-phenylalk-1-ene regioisomers showed that COX-1 inhibition decreased, COX-2 inhibition increased, and the COX-2 selectivity index (SI) increased as the chain length of the alkyl substituent attached to the olefinic double bond was increased (Et → n-butyl → n-heptyl). In this group of compounds, inhibition of both 5-LOX and 15-LOX was dependent upon the length of the alkyl substituent with the hex-1-ene compound 9c having a n-butyl substituent exhibiting potent inhibition of both 5-LOX (IC50 = 0.3 μM) and 15-LOX (IC50 = 0.8 μM) relative to the inactive (IC50 > 10 μM) Et and n-heptyl analogs. Compound 9c is of particular interest since it also exhibits a dual inhibitory activity against the COX (COX-1 IC50 = 3.0 μM, and COX-2 IC50 = 0.36 μM, COX-2 SI = 8.3) isozymes. A comparison of the relative inhibitory activities of the two groups of regioisomers investigated shows that the regioisomers in which the alkyl substituent is attached to the same olefinic carbon atom (C-2) as the para-methanesulfonylphenyl moiety generally exhibit a greater potency with respect to COX-2 inhibition. The 4-hydroxy substituent in the 3,5-di-tert-butyl-4-hydroxyphenyl moiety is essential for COX and LOX inhibition since 3,5-di-tert-butyl-4-acetoxyphenyl derivatives were inactive inhibitors. These structure-activity data indicate acyclic triaryl (Z)-olefins constitute a suitable template for the design of dual COX-2/LOX inhibitors.
Diarylmethylidenefuran derivatives and their uses in therapeutics
-
, (2008/06/13)
The present invention relates to the derivatives of the formula STR1 and to their use in therapeutics, especially as drugs with anti-inflammatory and analgesic properties.
