Metal-Free Chemoselective S-Arylation of Sulfenamides To Access Sulfilimines.

A novel and efficient S-arylation of sulfenamides with diaryliodonium salts for the synthesis of sulfilimines is developed. The reaction proceeds smoothly under transition-metal-free and air conditions, giving rapid access to sulfilimines in good to excellent yields via selective S-C bond formation. This protocol is scalable and exhibits a broad substrate scope, good functional group tolerance, and excellent chemoselectivity.

Photoinduced Synthesis of Sulfonyl-Containing Phosphorothioates via a Three-Component Reaction.

Both sulfonyl and phosphorothioate are important privileged structural motifs which are widely presented in pharmaceuticals and agrochemicals. Herein, we describe an efficient approach to synthesizing sulfonyl-containing phosphorothioates by merging photoredox and copper catalysis at room temperature. This protocol is compatible with a wide range of substrates and can be applied to the late-stage modification of complex molecules. Control experiments are conducted to demonstrate the generation of the sulfonyl radical in the transformation.

Shotgun metagenomics reveals both taxonomic and tryptophan pathway differences of gut microbiota in major depressive disorder patients.

BACKGROUND: The microbiota-gut-brain axis, especially the microbial tryptophan (Trp) biosynthesis and metabolism pathway (MiTBamp), may play a critical role in the pathogenesis of major depressive disorder (MDD). However, studies on the MiTBamp in MDD are lacking. The aim of the present study was to analyze the gut microbiota composition and the MiTBamp in MDD patients. METHODS: We performed shotgun metagenomic sequencing of stool samples from 26 MDD patients and 29 healthy controls (HCs). In addition to the microbiota community and the MiTBamp analyses, we also built a classification based on the Random Forests (RF) and Boruta algorithm to identify the gut microbiota as biomarkers for MDD. RESULTS: The Bacteroidetes abundance was strongly reduced whereas that of Actinobacteria was significantly increased in the MDD patients compared with the abundance in the HCs. Most noteworthy, the MDD patients had increased levels of Bifidobacterium, which is commonly used as a probiotic. Four Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologies (KOs) (K01817, K11358, K01626, K01667) abundances in the MiTBamp were significantly lower in the MDD group. Furthermore, we found a negative correlation between the K01626 abundance and the HAMD scores in the MDD group. Finally, RF classification at the genus level can achieve an area under the receiver operating characteristic curve of 0.890. CONCLUSIONS: The present findings enabled a better understanding of the changes in gut microbiota and the related Trp pathway in MDD. Alterations of the gut microbiota may have the potential as biomarkers for distinguishing MDD patients form HCs.

Direct C-H Methylsulfonylation of Alkenes with the Insertion of Sulfur Dioxide.

The direct C-H methylsulfonylation of alkenes using inorganic sodium metabisulfite as the sulfur dioxide surrogate is described. This method provides convenient access to (E)-2-methyl styrenyl sulfones in good yields. In general, the in situ generated methyl radical from di-tert-butyl peroxide undergoes a methylsulfonylation process with the combination of sulfur dioxide.

DMC1 mutation that causes human non-obstructive azoospermia and premature ovarian insufficiency identified by whole-exome sequencing.

BACKGROUND: The genetic causes of the majority of male and female infertility caused by human non-obstructive azoospermia (NOA) and premature ovarian insufficiency (POI) with meiotic arrest are unknown. OBJECTIVE: To identify the genetic cause of NOA and POI in two affected members from a consanguineous Chinese family. METHODS: We performed whole-exome sequencing of DNA from both affected patients. The identified candidate causative gene was further verified by Sanger sequencing for pedigree analysis in this family. In silico analysis was performed to functionally characterise the mutation, and histological analysis was performed using the biopsied testicle sample from the male patient with NOA. RESULTS: We identified a novel homozygous missense mutation (NM_007068.3: c.106G>A, p.Asp36Asn) in DMC1, which cosegregated with NOA and POI phenotypes in this family. The identified missense mutation resulted in the substitution of a conserved aspartic residue with asparaginate in the modified H3TH motif of DMC1. This substitution results in protein misfolding. Histological analysis demonstrated a lack of spermatozoa in the male patient's seminiferous tubules. Immunohistochemistry using a testis biopsy sample from the male patient showed that spermatogenesis was blocked at the zygotene stage during meiotic prophase I. CONCLUSIONS: To the best of our knowledge, this is the first report identifying DMC1 as the causative gene for human NOA and POI. Furthermore, our pedigree analysis shows an autosomal recessive mode of inheritance for NOA and POI caused by DMC1 in this family.

Regioselective Iodine-Catalyzed Construction of Polysubstituted Pyrroles from Allenes and Enamines.

A novel I2-catalyzed tandem Michael addition/oxidative annulation of allenes and enamines for the construction of polysubstituted pyrroles has been developed. This protocol represents an efficient and highly regioselective way to access functionalized pyrroles in moderate to excellent yields under mild conditions.

Ligand-Enabled Copper-Catalyzed Ullmann-Type S-C Bond Formation to Access Sulfilimines.

A copper-catalyzed Ullmann-type cross-coupling reaction of sulfenamides with aryl iodides is developed. The key to success is the use of a 2-methylnaphthalen-1-amine-derived amide ligand, which enables the formation of an S-C bond to access functionalized sulfilimines in good to excellent yields at room temperature. This method has the advantages of mild conditions, a broad substrate scope, good functional group compatibility, and high chemoselectivity. The utility of this protocol is highlighted through late-stage modification of drug-relevant molecules and sulfilimine product derivatization.

Synthesis of Sulfilimines via Aryne and Cyclohexyne Intermediates.

An efficient and metal-free approach for the synthesis of sulfilimines from sulfenamides with aryne and cyclohexyne precursors has been developed. The reaction proceeds through unusual S-C bond formation, which offers a novel and practical entry to access a wide range of sulfilimines in moderate to good yields with excellent chemoselectivity. Moreover, this protocol is amenable to gram-scale synthesis and is applicable to the transformation of the products into useful sulfoximines.

Access to chiral ß-sulfonyl carbonyl compounds via photoinduced organocatalytic asymmetric radical sulfonylation with sulfur dioxide.

An organocatalytic enantioselective radical reaction of potassium alkyltrifluoroborates, DABCO·(SO2)2 and α,ß-unsaturated carbonyl compounds under photoinduced conditions is developed, which provides an efficient pathway for the synthesis of chiral ß-sulfonyl carbonyl compounds in good yields with excellent enantioselectivity (up to 96% ee). Aside from α,ß-unsaturated carbonyl compounds with auxiliary groups, common chalcone substrates are also well compatible with this organocatalytic system. This method proceeds through an organocatalytic enantioselective radical sulfonylation under photoinduced conditions, and represents a rare example of asymmetric transformation involving sulfur dioxide insertion.

Photoredox-Catalyzed α-Sulfonylation of Ketones from Sulfur Dioxide and Thianthrenium Salts.

A photoredox-catalyzed sulfonylation of silyl enol ethers with DABCO·(SO2)2 and thianthrenium salts is achieved, providing diverse ß-keto sulfones in moderate to good yields. This protocol features easily accessible starting materials and good functional group compatibility, enabling the introduction of various functionalized sulfonyl groups into ketones. Furthermore, as one of the important industrial raw materials, methanol can be employed as the methyl source to prepare α-methylsulfonated ketones through a methyl thianthrenium intermediate for the first time.

Synthesis of ß-cyanoalkylsulfonylated vinyl selenides through a four-component reaction.

A mild copper-catalyzed four-component selenosulfonylation of alkynes, cycloketone oxime esters, DABCO (SO2)2 and diselenides has been developed. This method enables the rapid assembly of ß-cyanoalkylsulfonylated vinyl selenides in moderate to good yields. Advantages of this protocol include a broad substrate scope, good functional group tolerance and the late-stage functionalization of complex molecules. Moreover, the potential utility of this methodology is demonstrated through simple oxidation of the products to access synthetically important alkynyl sulfones. Mechanistic studies suggest that a cyanoalkylsulfonyl radical intermediate is involved in this process.

Copper-Catalyzed Regioselective 1,4-Selenosulfonylation of 1,3-Enynes to Access Cyanoalkylsulfonylated Allenes.

By employing CuOAc as the catalyst, we realize a four-component reaction of 1,3-enynes, diselenides, DABCO·(SO2)2, and cycloketone oxime esters, providing facile access to diverse cyanoalkylsulfonylated allenyl selenides in moderate to good yields. This reaction features high functional group tolerance and a broad substrate scope, enabling the regioselective, sequential formation of C-SO2 and C-Se bonds under mild reaction conditions. Moreover, the utility of this methodology is further illustrated through the late-stage functionalization of drug-based molecules.

Photoinduced intramolecular carbosulfonylation of alkynes: access to sulfone-containing dibenzazepines from sulfur dioxide.

A photoinduced three-component reaction of N-benzyl-N-(2-ethynylaryl)amides, sulfur dioxide and aryldiazonium tetrafluoroborates is developed, providing an efficient and straightforward approach for the synthesis of diverse vinylsulfonylated dibenzazepine derivatives in moderate to good yields under mild conditions. This transformation proceeds smoothly at room temperature in the presence of visible light, which shows a wide range of substrate scope with good functional group compatibility. The synthetic utility of this methodology is further demonstrated through Suzuki coupling. Mechanistic studies show that this reaction is triggered by the addition of an arylsulfonyl radical to an alkyne from sulfur dioxide, followed by vinyl radical cyclization to afford the desired sulfonated dibenzazepines.

Synthesis and biological evaluation of fluorinated 3,4-dihydroquinolin-2(1H)-ones and 2-oxindoles for anti-hepatic fibrosis.

(Z)-4-(Iodomethylene)-3-(2,2,2-trifluoroethyl)-3,4-dihydroquinolin-2(1H)-ones and fluorinated 3,3-disubstituted 2-oxindoles are synthesized and evaluated for anti-hepatic fibrosis. CCK-8 assay indicates that most of the compounds have no obvious cytotoxicity on the human hepatic stellate cells (HSC) cell line. Collagen I and fibrosin expression levels are tested by ELISA, and the results show that several compounds can inhibit the expression of collagen I and fibrosin. Additionally, results from real time-PCR reveal that only one compound can inhibit the expression level of α-SMA, suggesting that this compound can inhibit the activation of the HSC cell line. These studies demonstrate that this compound may be a potential novel drug candidate for anti-hepatic fibrosis (approximately 5-6 lines).

Shotgun metagenomics reveals both taxonomic and tryptophan pathway differences of gut microbiota in bipolar disorder with current major depressive episode patients.

BACKGROUND: The microbiome-gut-brain axis, especially the microbial tryptophan biosynthesis and metabolism pathway (MiTBamp), is closely connected to bipolar disorder with current major depressive episode (BPD). METHODS: We performed shotgun metagenomics sequencing (SMS) of faecal samples from 25 BPD patients and 28 healthy controls (HCs). Except for the microbiota taxa and MiTBamp analyses, we also built a classification model using the Random Forests (RF) and Boruta algorithm to find the microbial biomarkers for BPD. RESULTS: Compared to HCs, the phylum Bacteroidetes abundance was significantly reduced, whereas that of the Actinobacteria and Firmicutes were significantly increased in BPD patients. We also identified 38 species increased and 6 species decreased significantly in the BPD group. In the MiTBamp, we identified that two Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologies (KOs) (K00658 and K00837) were significantly lower in the BPD, and five KOs (K01696, K00382, K00626, K01667, and K03781) were significantly higher in the BPD group. We also identified significant genera and species which were closely related to these KOs. Finally, RF classification based on gut microbiota at the genus level can achieve an area under the receiver operating characteristic curve of 0.997. LIMITATIONS: The features of cross-sectional design, limited sample size, the heterogeneity of bipolar disorders, and a lack of serum/plasma tryptophan concentration measurements. CONCLUSIONS: The present findings enable a better understanding of changes in gastrointestinal microbiome and MiTBamp in BPD. Alterations of microbes may have potential as biomarkers for distinguishing the BPD patients form HCs.

Photoredox-catalyzed sulfonylation of difluoroenoxysilanes with the insertion of sulfur dioxide.

A photoredox-catalyzed three-component reaction of aryldiazonium tetrafluoroborates with sodium metabisulfite and 2,2-difluoro enol silyl ethers is described. By using sodium metabisulfite as the source of sulfur dioxide, this method provides an elegant access to α,α-difluoro-ß-ketosulfones in moderate to good yields under mild conditions, and features a broad substrate scope and wide functional group tolerance. Both of the difluoromethyl group and sulfone moiety can be introduced in a single step. Based on the experimental results, a single-electron transfer pathway is proposed with the insertion of sulfur dioxide.

A copper-catalyzed insertion of sulfur dioxide via radical coupling.

A copper-catalyzed three-component reaction of O-acyl oximes, DABCO·(SO2)2, and 2H-azirines under mild conditions has been achieved. This protocol provides an efficient route for the construction of various tetrasubstituted ß-sulfonyl N-unprotected enamines in moderate to good yields with excellent stereoselectivity and regioselectivity. Notably, this method represents a rare example of 2H-azirines as useful synthons for ß-functionalized N-unprotected enamines. Preliminary mechanistic studies indicate that the reaction proceeds through coupling of a sulfonyl radical and α-carbon radical via copper-catalyzed ring-opening C-C bond cleavage of O-acyl oxime and C-N bond cleavage of 2H-azirine with the insertion of sulfur dioxide.

Similarly in depression, nuances of gut microbiota: Evidences from a shotgun metagenomics sequencing study on major depressive disorder versus bipolar disorder with current major depressive episode patients.

BACKGROUND: To probe the differences of gut microbiota among major depressive disorder (MDD), bipolar disorder with current major depressive episode (BPD) and health participants. METHODS: Thirty one MDD patients, thirty BPD patients, and thirty healthy controls (HCs) were recruited. All the faecal samples were analyzed by shotgun metagenomics sequencing. Except for routine analyses of alpha diversity, we specially designed a new indicator, the Gm coefficient, to evaluate the inequality of relative abundances of microbiota for each participant. RESULTS: The Gm coefficients are significant decreased in both MDD and BPD groups. The relative abundances of increased phyla Firmicutes and Actinobacteria and decreased Bacteroidetes were significantly in the MDD and BPD groups. At genus level, four of top five enriched genera (Bacteroides, Clostridium, Bifidobacterium, Oscillibacter and Streptococcus) were found increased significantly in the MDD and BPD groups compared with HCs. The genera Escherichia and Klebsiella showed significant changes in abundances only between the BPD and HC groups. At the species level, compared with BPD patients, MDD patients had a higher abundance of Prevotellaceae including Prevotella denticola F0289, Prevotella intermedia 17, Prevotella ruminicola, and Prevotella intermedia. Furthermore, the abundance of Fusobacteriaceae, Escherichia blattae DSM 4481 and Klebsiella oxytoca were significantly increased, whereas the Bifidobacterium longum subsp. infantis ATCC 15697 = JCM 1222 was significantly reduced in BPD group compared with MDD group. CONCLUSIONS: Our study suggested that gut microbiota may be involved in the pathogenesis of both MDD and BPD patients, and the nuances of bacteria may have the potentiality of being the biomarkers of MDD and BPD.

ß-Silyl Acrylates in Asymmetric [3 + 2] Cycloadditions Affording Pyrrolidine Azasugar Derivatives.

A highly efficient copper(I)-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides with 3-silyl unsaturated esters has been developed, providing elegant access to chiral 3-silylpyrrolidine derivatives bearing contiguous stereogenic centers in moderate-to-excellent yields (up to 99%) with high diastereo- and enantioselectivities (dr up to >99:1; ee up to 96%). Notably, the 3-silylpyrrolidines can easily be converted to pyrrolidine azasugar derivatives with potential biological activities by the reduction of two ester groups and carbon-silicon bond oxidation.

Asymmetric Construction of 3,4-Diamino Pyrrolidines via Chiral N,O-Ligand/Cu(I) Catalyzed 1,3-Dipolar Cycloaddition of Azomethine Ylides with ß-Phthalimidonitroethene.

A series of chiral N,O-ligands derived from a 1,2-dihydroimidazo[1,2-a]quinolone motif have been evaluated for the asymmetric 1,3-dipolar cycloaddition of azomethine ylides with a novel dipolarophile ß-phthalimidonitroethene. A newly designed DHIPOH ligand 7c bearing 1-methyl and 4-iodo substituents was found to have significant "synergistic steric effects" and consequently afforded the corresponding 4-nitro-3-aminopyrrolidines with excellent diastereo- (dr up to 98:2) and enantio selectivities (ee up to 99%). Subsequent Raney Ni-catalyzed reduction and deprotection of phthalyl led to the structurally and biologically important 3,4-diaminopyrrolidines in a straightforward and efficient pathway.