Access to 1-aryl-pyrazolin-5-ones photoinduced chemoselective cyclization of -methacrylo aldehyde hydrazones.

A photocatalytic sulfamoylation/5- cyclization of ()-'-arylidene--phenylmethacrylohydrazides with sulfamoyl chlorides was developed. The chemoselective intramolecular addition of the carbon-centered radical intermediate to the CN bond in the hydrazone motif gave the sulfamoylated pyrazolin-5-one. Besides, sulfonyl chlorides are also suitable reaction partners to access sulfonylated pyrazolin-5-ones.

Organophotocatalytic pyridination of -arylglycines with 4-cyanopyridines by decarboxylative and decyanative radical-radical coupling.

A photocatalytic decarboxylative aminoalkylation of 4-cyanopyridines with -arylglycines is achieved, providing 4-(aminomethyl)pyridine derivatives in moderate to good yields. This organic photocatalytic reaction undergoes a radical-radical cross-coupling process under redox-neutral conditions, featuring simple operation, readily available -arylglycines and a broad substrate scope. Mechanistic investigations indicated that a proton-coupled electron-transfer process was involved to enable the single electron transfer between the reduced photocatalyst and 4-cyanopyridine in the presence of -arylglycines.

Photocatalytic synthesis of polyfluoroalkylated dihydropyrazoles and tetrahydropyridazines.

A photocatalytic trifluoromethylation/cyclization reaction of -allyl and -homoallyl aldehyde hydrazones with trifluoromethyl thianthrenium triflate was developed for the synthesis of trifluoromethylated dihydropyrazoles and tetrahydropyridazines. Besides, PhI(OCCHF) was employed to realize the construction of difluoromethylated dihydropyrazoles and tetrahydropyridazines. These protocols exhibit a broad substrate scope and good functional group tolerance.

Advances in the synthesis of functionalized tetrahydropyridazines from hydrazones.

The tetrahydropyridazine motif is widely present in plenty of natural products and biologically active molecules. Easily prepared from the condensation of carbonyls with hydrazines, hydrazones are versatile synthetic building blocks that are frequently used in organic synthesis. Hydrazones are also utilized in the synthesis of nitrogen-containing molecules, especially nitrogen-containing heterocycles.

Photo-induced phosphorylation/cyclization of -homoallyl and -allyl aldehyde hydrazones to access phosphorylated tetrahydropyridazines and dihydropyrazoles.

A photocatalytic radical carbophosphorylation/cyclization of -homoallyl aldehyde hydrazones with phosphine oxides was developed under metal-free conditions, achieving phosphorylated tetrahydropyridazines in yields up to 95%. Phosphorylated dihydropyrazoles were also constructed, by reacting -allyl aldehyde hydrazones with phosphine oxides under the same conditions.

Photocatalytic redox-neutral α-C(sp)-H pyridination of glycine derivatives and -arylamines with cyanopyridines.

A photo-induced α-C(sp)-H decyanative pyridination of -arylglycine derivatives with cyanopyridines was developed. This reaction was performed under organic photocatalytic and redox-neutral conditions a radical-radical cross-coupling process. Besides, the protocol was also suitable for the C(sp)-H pyridination of -aryl tetrahydroisoquinolines as well as benzylamines.

Photocatalytic cyclization of 3-(2-isocyanophenyl)quinazolin-4(3)-ones for the construction of quinoxalino[2,1-]quinazolinones.

A new kind of building unit, 3-(2-isocyanophenyl)quinazolin-4(3)-ones, was designed and synthesized for the construction of novel quinoxalino[2,1-]quinazolinones. The radical cyclization of 3-(2-isocyanophenyl)quinazolin-4(3)-ones with ethers afforded ether-substituted tetracyclic quinoxalino[2,1-]quinazolinones under photocatalytic and metal-free conditions. In the process, the isocyano accepts a carbon radical to give an imidoyl radical, which adds to the electron-deficient CN bond in quinazolin-4(3)-one.

Photocatalytic Carbosulfonylation/Cyclization of -Homoallyl and -Allyl Aldehyde Hydrazones toward Sulfonylated Tetrahydropyridazines and Dihydropyrazoles.

'-Benzylidene--homoallylacetohydrazides were designed and synthesized as novel skeletons for the construction of functionalized tetrahydropyridazines. A series of aryl- and alkylsulfonylated tetrahydropyridazines were obtained in yields of up to 94% employing sulfonyl chlorides as the sulfonyl radical sources under visible-light irradiation. Besides, sulfonylated dihydropyrazoles were also produced from -allyl-'-benzylideneacetohydrazides.

Metal-free polychloromethylation/cyclization of unactivated alkenes towards ring-fused tricyclic indolones and benzoimidazoles.

Polychloromethylative cyclization of -alkenyl indoles was developed under metal-free conditions to afford tricyclic pyridoindolones and pyrroloindolones in moderate to good yields. In the reaction, commercially available CHCl and CHCl were employed as tri- and dichloromethyl radical sources. Moreover, tri- and dichloromethylated polycyclic benzoimidazoles can also be obtained under standard conditions.

Photocatalytic chemo-, regio- & stereoselective olefinic β-C-H decarboxylative alkylation of enamides with diacyl peroxides.

A decarboxylative alkylation of enamides with alkyl diacyl peroxides induced by visible-light is described. The chemo-, regio- and stereoselective olefinic β-C-H alkylation generates a series of primary- and secondary alkylated enamides in yields up to 95%. This transformation bears the advantages of operational simplicity, good functional group compatibility and mild conditions.

Metal-Free Photoinduced Hydrocyclization of Unactivated Alkenes toward Ring-Fused Quinazolin-4(3)-ones via Intermolecular Hydrogen Atom Transfer.

A visible-light-induced hydrocyclization of unactivated alkenes was developed using 3CzClIPN as the photocatalyst to generate substituted α-methyldeoxyvasicinones and α-methylmackinazolinones in moderate to good yields. An intermolecular hydrogen atom transfer with THF as the hydrogen source was involved. Mechanism studies indicated that the intramolecular addition of the formed aminal radical to the unactivated alkene generated the polycyclic quinazolinone.

Substituent-Controlled Regioselective Photoinduced Cyclization of -Allylbenzamides with -Sulfonylaminopyridinium Salts.

The annulation reactions of -allylbenzamides with -sulfonylaminopyridinium salts were developed under metal-free photoinduced mild conditions. Substituent-controlled sulfonaminoarylation and sulfonaminooxylation of benzamides were realized: -allylbenzamides lead to benzosultams, while -(2-phenylallyl)benzamides give sulfonamidylated oxazoline derivatives. Control experiments indicated that those reactions undergo a radical pathway with arylsulfonamidyl radicals as the intermediates.

[Effects of Continuous Straw Returning with Chemical Fertilizer on the Carbon Pool and Crop Yield of Rice-Rape Rotation Soils].

According to the positioning experiment of straw returning in the continuous field 7a, the effects of straw returning combined with chemical fertilizer on soil total organic carbon (TOC), dissolved organic carbon (DOC), particulate organic carbon (POC), labile organic carbon (LOC), carbon pool management index (CPMI), and crop yield in farmland soil profiles (0-20, 20-50, and 50-80 cm) in the Chaohu Lake area were studied. There were four treatments:no straw returning+no fertilization (CK), conventional fertilization (F), straw returning+conventional fertilization (SF1), and straw returning+80% conventional fertilization (SF2). The changes in soil total organic carbon and component content, CPMI, and rape rice yield in different soil layers were analyzed.

Recent advances in C-H functionalization of 2-indazoles.

2-Indazoles are one class of the most important nitrogen-containing heterocyclic compounds. The 2-indazole motif is widely present in bioactive natural products and drug molecules that exhibit distinctive bioactivities. Therefore, much attention has been paid to access diverse 2-indazole derivatives.

Metal-free polychloromethyl radical-initiated cyclization of unactivated -allylindoles towards pyrrolo[1,2-]indoles.

A metal-free polychloromethyl radical-initiated cyclization of unactivated alkenes was developed using CHCl and CHCl as the di- and trichloromethyl radical sources. Variously substituted -allyl-indoles were successfully transformed into the corresponding C2-(di- and trichloromethyl) pyrrolo[1,2-]indoles in moderate to good yields. This reaction has a broad substrate scope and good functional group tolerance.

Three-component synthesis of arylsulfonyl-substituted indolo[2,1-]isoquinolinones and benzimidazo-[2,1-]isoquinolin-6(5)-ones by SO insertion and radical cascade cyclization.

An efficient arylsulfonylation/cyclization of 2-aryl--methacryloyl indoles with potassium metabisulfite and aryldiazonium tetrafluoroborates was developed. A series of variously substituted arylsulfonyl indolo[2,1-]isoquinolin-6(5)-ones were formed in moderate to good yields utilization of the nature abundant inorganic salt potassium metabisulfite as a SO surrogate. Additionally, this three-component protocol can also be employed for the synthesis of arylsulfonyl-substituted benzimidazo-[2,1-]isoquinolin-6(5)-ones.

Rhodium-catalyzed C-H activation/cyclization of aryl sulfoximines with iodonium ylides towards polycyclic 1,2-benzothiazines.

The synthesis of 1,2-benzothiazine derivatives through rhodium-catalyzed C-H activation/cyclization of -aryl sulfoximines with iodonium ylides was developed for the first time. In this report, C-H and N-H bond functionalization was realized towards a series of tricyclic and tetracyclic sulfoximine derivatives with moderate to excellent yields under simple reaction conditions.

Recent advances in rhodium-catalyzed C(sp)-H (hetero)arylation.

Arylation is a common behaviour in organic synthesis for the construction of complex structures, especially the biaryls. Among those reported arylation procedures, transition-metal-catalyzed direct C(sp)-H arylation has been rapidly developed in recent decades and has become a reliable alternative to traditional cross-coupling procedures using organometallic reagents. Great achievements in rhodium-catalyzed C(sp)-H arylation have been witnessed during the last decade.

Rh -Catalyzed C6-Selective Oxidative C-H/C-H Crosscoupling of 2-Pyridones with Thiophenes.

A rhodium(III)-catalyzed C6-selective dehydrogenative cross-coupling of 2-pyridones with thiophenes was developed for the synthesis of 6-thiophenyl pyridin-2(1H)-one derivatives. In this reaction, the excellent site selectivity was controlled by the 2-pyridyl directing group on the nitrogen of the pyridone ring. Control experiments indicated that the N-pyridyl was essential for the transformation.

Diacyl peroxides: practical reagents as aryl and alkyl radical sources.

Diacyl peroxides, which can be easily synthesized from corresponding carboxylic acids, are commonly utilized as radical initiators and one electron oxidants. Under thermal, transition-metal catalysis or irradiation conditions the cleavage of relatively weak O-O bonds would occur followed by CO extrusion to generate the corresponding aryl or alkyl radicals. Thus, diacyl peroxides can be employed as ideal arylating and alkylating reagents in organic synthesis, including C-H/N-H arylation/alkylation, aryl/alkyl radical addition to unsaturated bonds, hetero arylation/alkylation, eliminative arylation/alkylation, perfluoroalkylation etc.

DTBP-promoted site-selective α-alkoxyl C-H functionalization of alkyl esters: synthesis of 2-alkyl ester substituted chromanones.

The direct C-H functionalization of ethyl acetates was developed, delivering a variety of 1-(4-oxochroman-2-yl)ethyl acetate derivatives by reacting with chromones. This reaction has a wide substrate scope with excellent site-selective C-H activation at the inactive α-hydrogen of the alkoxyl group instead of the α-hydrogen of the carbonyl group under radical conditions. Compared with other protocols for the α-alkoxyl C-H functionalization of alkyl esters, a distinguishing feature of this reaction is that no metal catalyst was required, with DTBP as the sole oxidant.

Peroxide-mediated synthesis of benzimidazo[2,1-]isoquinoline-6(5)-ones cascade methylation/ethylation and intramolecular cyclization.

A metal-free oxidative radical methylation/arylation of 2-arylbenzoimidazoles with DTBP as the oxidant and methyl radical source was developed. The reaction proceeds through a sequential methyl radical addition/cyclization pathway and affords a series of methyl functionalized benzimidazo[2,1-a]isoquinoline-6(5H)-ones in moderate to good yields. Besides, the ethylation/arylation of 2-arylbenzoimidazoles was also achieved with DTAP.

Identification of candidate aberrantly methylated and differentially expressed genes in Esophageal squamous cell carcinoma.

Aberrant methylated genes (DMGs) play an important role in the etiology and pathogenesis of esophageal squamous cell carcinoma (ESCC). In this study, we aimed to integrate three cohorts profile datasets to ascertain aberrant methylated-differentially expressed genes and pathways associated with ESCC by comprehensive bioinformatics analysis. We downloaded data of gene expression microarrays (GSE20347, GSE38129) and gene methylation microarrays (GSE52826) from the Gene Expression Omnibus (GEO) database.

Rh(iii)-Catalyzed sequential ortho-C-H oxidative arylation/cyclization of sulfoxonium ylides with quinones toward 2-hydroxy-dibenzo[b,d]pyran-6-ones.

A rhodium(iii)-catalyzed ortho-C-H functionalization of sulfoxonium ylides followed by intramolecular annulation reactions with quinones was described, where the carbonyl in sulfoxonium ylides served as a chelation group. This protocol leads to the efficient formation of 2-hydroxy-6H-benzo[c]chromen-6-one derivatives, proceeding with the cleavage of the C(O)-S bond in sulfoxonium ylides. This protocol featured high chemo-selectivity and functional group tolerance, where sulfoxonium ylides acted as the aroyl sources.

Rh(iii)-Catalyzed regioselective C4 alkylation of indoles with allylic alcohols: direct access to β-indolyl ketones.

A Rh(iii)-catalyzed and weak coordination carbonyl guided direct C4 alkylation of indoles with allylic alcohols was developed with excellent regioselectivity. This reaction was conducted under mild conditions, leading to a variety of β-indolyl ketones with good functional group tolerance in moderate to good yields.