An organocatalyzed photoelectrochemical method for the generation of acyl and phosphoryl radicals from formamides, aldehydes, and phosphine oxides has been developed. This protocol utilizes 9,10-phenanthrenequinone (PQ) as both a molecular catalyst and a hydrogen atom-transfer (HAT) reagent, eliminating the requirement for external metal-based reagents, HAT reagents, and oxidants. The generated acyl radicals can be applied to a range of radical-mediated transformation reactions, including C-H carbamoylation of heteroarenes, intermolecular tandem radical cyclization of CF-substituted -arylacrylamides, as well as intramolecular cyclization reactions.
View Article and Find Full Text PDFAn organophotoelectrocatalytic method for the C(sp)-H alkylation of heteroarenes with unactivated C(sp)-H compounds through dehydrogenation cross-coupling has been developed. The C(sp)-H alkylation combines organic catalysis, photochemistry and electrochemistry, avoiding the need for external metal-reagents, HAT-reagents, and oxidants. This protocol exhibits good substrate tolerance and functional group compatibility, providing a straightforward and powerful pathway to access a variety of alkylated heteroarenes under green conditions.
View Article and Find Full Text PDFHerein, we present a transition-metal-free, easy handling protocol for regioselective carboxylation of -difluorostyrenes with sodium formate as the C1 source. 30 examples of α-fluoracrylates were obtained in yields of 30 to 80% under these conditions. A defluorinative monofluorovinyl intermediate and consecutive photoinduced electron transfer mechanism were proposed after mechanism investigation.
View Article and Find Full Text PDFOrganoelectrophotocatalytic generation of acyl radicals from formamides and aldehydes to synthesize acylated 3-CF-2-oxindoles has been developed. This protocol features a monocatalytic system using 9,10-phenanthrenequinone (PQ) both as a catalyst and as a hydrogen atom transfer (HAT) reagent, which avoids the use of an external HAT reagent, metal reagent, and oxidant. A variety of acylated 3-CF-2-oxindoles have been obtained in satisfactory yields from CF-substituted -arylacrylamides via a tandem radical cyclization.
View Article and Find Full Text PDFAn electrophilic spirocyclization of -benzylacrylamides with -halosuccinimides (NXS) as the halogenating reagents has been developed. This reaction is carried out at room temperature under simple conditions without relying on metal reagents, photochemistry, or electrochemistry, providing a fast and efficient route to synthesize a wide variety of 4-halomethyl-2-azaspiro[4.5]decanes with satisfactory yields.
View Article and Find Full Text PDFAn organoelectrophotocatalytic approach for the C-H silylation of heteroarenes through dehydrogenation cross-coupling with H evolution has been developed. The organoelectrophotocatalytic strategy is carried out under a simple and efficient monocatalytic system by employing 9,10-phenanthrenequinone both as an organocatalyst and as a hydrogen atom transfer (HAT) reagent, which avoids the need for an external HAT reagent, an oxidant, or a metal reagent. A variety of heteroarenes can be compatible in satisfactory yields with excellent regioselectivity.
View Article and Find Full Text PDFAn electrochemical monofluoroalkylation cyclization of -arylacrylamides to synthesize monofluorinated 2-oxindoles has been developed, which employs common dimethyl 2-fluoromalonate as a monofluoroalkyl radical precursor and obviates the use of prefunctionalized monofluoroalkylation reagents and sacrificial oxidants. A variety of monofluorinated nitrogen-containing heterocyclic compounds were efficiently obtained with satisfactory yields from readily available materials.
View Article and Find Full Text PDFObjective: To observe the effect of ( stone plaste) pretreatment on serum level of prolyl hydroxylase domain 2 (PHD2) and hypoxia-inducible factor-1α (HIF-1α) in rats with acute hypobaric hypoxia induced-brain injury, and to explore the possible mechanism of on preventing brain injury at high altitude.
Methods: Forty-five male SD rats were randomly divided into a blank group, a model group, a Biantie group, a medication group and a Biantie+inhibitor group, 9 rats in each group. The rats in the Biantie group the and the Biantie+inhibitor group were pretreated with at "Taiyuan" (LU 9), "Neiguan" (PC 6) and "Renying" (ST 9), 2 h each time, once a day; the rats in the medication group were treated with intragastric administration of rhodiola capsule solution (280 mg/kg) for 14 d; the rats in the Biantie+inhibitor group were intraperitoneally injected with the PHD inhibitor dimethyloxalyl glycine (DMOG) at a dose of 40 mg/kg 24 h before the establishment of the model.
An electrochemical dearomatizing spirocyclization of alkynes with dimethyl 2-benzylmalonates for the preparation of spiro[4.5]deca-trienones has been developed. This approach adopts ferrocene (CpFe) as an electrocatalyst to produce carbon-centered radical intermediates from C-H-based malonates, which obviates the forthputting of noble-metal reagents, sacrificial chemical oxidants and 2-bromomalonates.
View Article and Find Full Text PDFA site-selective electrochemical approach for the benzylic C(sp)-H oxidation reaction of phenol derivatives along with hydrogen evolution has been developed. The protocol proceeds in an easily available undivided cell at room temperature under catalyst- and oxidizing reagent-free conditions. The corresponding aryl aldehydes and ketones are obtained in satisfactory yields, and the gram-scale synthesis is easy to be carried out.
View Article and Find Full Text PDFAn electrochemical approach for the preparation of monofluorides from α,β-unsaturated carboxylic acids and heteroaromatics with readily available 2-fluoromalonate esters as monofluoroalkyl radical precursors has been developed. The electrosynthesis employs ferrocene (CpFe) as a catalyst in a simple undivided cell with a broad substrate scope, which obviates the need for sacrificial oxidizing reagents.
View Article and Find Full Text PDFThe development of electrocatalytic synthetic methods hinges on efficient molecular catalysts. Triarylamines are well-known redox catalysts because of the good stability of their corresponding amine radical cations. Herein we show that tris(4-(-butyl)phenyl)amine decomposes unexpectedly during electrolysis in MeOH/THF to afford a tetraarylhydrazine, 1,1,2,2-tetrakis(4-(-butyl)phenyl)hydrazine.
View Article and Find Full Text PDFAn electrochemical approach for the site-selective C-H cyanation of indoles employing readily available TMSCN as cyano source has been developed. The electrosynthesis relies on the tris(4-bromophenyl)amine as a redox catalyst, which achieves better yield and regioselectivity. A variety of C2- and C3-cyanated indoles were obtained in satisfactory yields.
View Article and Find Full Text PDFC-H/N-H cross-coupling is an ideal strategy to synthesize various amines but remains challenging owing to the requirement for sacrificial chemical oxidants and the difficulty in controlling the regio- and chemo-selectivity. Herein we report a site-selective electrochemical amination reaction that can convert benzylic C-H bonds into C-N linkages via H evolution without need for external oxidants or metal catalysts. The synthetic strategy involves anodic cleavage of benzylic C-H to form a carbocation intermediate, which is then trapped with an amine nucleophile leading to C-N bond formation.
View Article and Find Full Text PDFA diastereoselective approach to axially chiral imidazopyridine-containing biaryls has been developed. The reactions proceed through a radical cyclization cascade to construct the biaryls with good to excellent central-to-axial chirality transfer.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
March 2019
A photoelectrochemical method for the C-H alkylation of heteroarenes with organotrifluoroborates has been developed. The merger of electrocatalysis and photoredox catalysis provides a chemical oxidant-free approach for the generation and functionalization of alkyl radicals from organotrifluoroborates. A variety of heteroarenes were functionalized using primary, secondary, and tertiary alkyltrifluoroborates with excellent regio- and chemoselectivity.
View Article and Find Full Text PDFApplication of metal-organic frameworks (MOFs) in electrocatalysis is of great interest, but is limited by low electrical conductivities of most MOFs. To overcome this limitation, we constructed a two-dimensional version of MOF-metal-organic layer (MOL) on conductive multiwalled carbon nanotubes (CNTs) via facile solvothermal synthesis. The redox-active MOLs supported on the CNT efficiently catalyze the electrochemical oxidation of alcohols to aldehydes and ketones.
View Article and Find Full Text PDFWe have developed a unified strategy for preparing a variety of imidazo-fused N-heteroaromatic compounds through regiospecific electrochemical (3+2) annulation reaction of heteroarylamines with tethered internal alkynes. The electrosynthesis employs a novel tetraarylhydrazine as the catalyst, has a broad substrate scope, and obviates the need for transition-metal catalysts and oxidizing reagents.
View Article and Find Full Text PDFWe report herein an atom-economical and sustainable approach to access amidinyl radical intermediates through the anodic cleavage of N-H bonds. The resulting nitrogen-centered radicals undergo cyclizations with (hetero)arenes, followed by rearomatization, to afford functionalized tetracyclic benzimidazoles in a highly straightforward and efficient manner. This metal- and reagent-free C-H/N-H cross-coupling reaction exhibits a broad substrate scope and proceeds with high chemoselectivity.
View Article and Find Full Text PDFObjective: To observe the effect of moxibustion stimulation of "Ganshu"(BL 18) region on contents of T cells in the peripheral blood in rats with Diethylnitrosamine (DEN)-induced hepatocellular carcinoma (HCC), so as to explore its effective in improving immunoregulatory function.
Methods: Seventy male Wistar rats were randomly divided into control group (=10), model group(=15), direct moxibustion-15 s group(=15), direct moxibustion-30 s group (=15) and ginger-separated moxibustion group(=15). The primary HCC precancerous lesion model was established by intraperitoneal injection of DEN (50 mg/kg), once every 3 days for 10 weeks.
Indoles and azaindoles are among the most important heterocycles because of their prevalence in nature and their broad utility in pharmaceutical industry. Reported herein is an unprecedented noble-metal- and oxidant-free electrochemical method for the coupling of (hetero)arylamines with tethered alkynes to synthesize highly functionalized indoles, as well as the more challenging azaindoles.
View Article and Find Full Text PDFObjective: To investigate the effect of direct moxibustion at Ganshu (BL18) on the serum concentrations of tumor specific growth factor (TSGF) and tumor necrosis factor α (TNF-α) in a rat model with precancerous lesion of primary hepatocellular carcinoma (HCC), so as to explore the mechanism of moxibustion underlying improvement of HCC.
Methods: Sixty male Wistar rats were randomly divided into control group (n=10), model group (n=20), prevention group 1 (n=15) and prevention group 2 (n=15). The normal rats were injected with physiological saline as blank control.
Objective: To observe the effect of moxibustion at "Ganshu" (BL18) on levels of Livin (a novel member of the inhibitors of apoptosis family and plays crucial roles in apoptosis, cell proliferation, and cell cycle control) in the liver tissue in rats with precancerous lesion of primary hepatocellular carcinoma (HCC), so as to explore its mechanism underlying improvement of HCC.
Methods: Sixty male Wistar rats were randomly divided into control group (n = 10), model group (n = 20), moxibustion-20 d group (n = 15) and moxibustion-40 d group (n = 15). HCC model was established by intraperitoneal injection of diethylnitrosamine (DEN, 50 mg/kg), once every 3 days for 12 weeks.
Objective: To explore the performance patterns of reaction point Jingtong in balance acupuncture through multi-center and big-sample clinical investigation. Methods The Jingtong points of balance acupuncture on healthy side and affected side were observed among 230 cases of cervical spondylosis and scores of self-discomfort in reaction point, color of skin, changes of skin, morphology of subcutaneous tissue and abnormal pressing pain were recorded. The software SPSS 15.
View Article and Find Full Text PDFObjective: To observe the physiological and psychological effects of Chinese traditional healthcare exercises (CTHE) on the adolescents.
Methods: A total of 136 healthy students of junior school were recruited and randomly divided into the test group (68 cases) and the control group (68 cases). The subjects in the test group practiced CTHE, while those in the control group did "the 8th radio calisthenics", an official recommended calisthenics for promoting healthcare in China, 3 times a week, and 7 weeks practicing overall.