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1.
Artigo em Inglês | MEDLINE | ID: mdl-32013385

RESUMO

A novel hybrid drug nanocarrier is developed with CuCo2S4 nanoparticles as the core to be encapsulated by poly(ionic liquid) (PIL), that is, poly(tetrabutylphosphonium styrenesulfonate) (P[P4,4,4,4][SS]), as the shell. Doxorubicin (DOX) is loaded onto the PIL shell via electrostatic attraction involving amine in DOX and styrenesulfonate in PIL. pH- and thermal-responsive characteristics of P[P4,4,4,4][SS] endow the multifunctional hybrid nanocarrier system DOX-CuCo2S4@PIL with sensitive dual-stimuli-triggered drug release behaviors. The CuCo2S4 core converts near-infrared (NIR) irradiation into thermal energy to trigger the shrinkage of the PIL shell, which subsequently promotes drug release, and the pH-responsive release of DOX involves pH-sensitive electrostatic interaction of the PIL shell with DOX. A favorable controlled release of 90.5% is achieved under pH/thermo dual stimuli. In vitro experiments with MCF-7 cells well demonstrated that the drug release is controlled by the acidic intracellular environment with NIR irradiation. The CuCo2S4 core also serves as a photoacoustic (PA) imaging contrast agent, as demonstrated by in vivo treatment of the MCF-7-carrying mice.

2.
Mol Biol Evol ; 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-32027372

RESUMO

Pikas are widely distributed in the Northern Hemisphere and are highly adapted to cold and alpine environments. They are one of the most complex and problematic groups in mammalian systematics, and the origin and evolutionary history of extant pikas remain controversial. In this study, we sequenced the whole coding sequences of 105 pika samples (29 named species, 1 putative new species) and obtained DNA data for more than 10000 genes. Our phylogenomic analyses recognized four subgenera of extant pikas: Alienauroa, Conothoa, Ochotona and Pika. The interrelationships between the four subgenera were strongly resolved as (Conothoa, (Alienauroa, (Ochotona, Pika))), with the mountain group Conothoa being the sister group of all other pikas. Our divergence time and phylogeographic analyses indicated that the last common ancestor of extant pikas first occurred on in the middle Miocene, approximately 14 million years ago. The emergence of opportunities related to the climate, food supply and spreading paths in concert promoted the dispersal of pikas from the Qinghai-Tibetan Plateau (QTP) to other parts of Eurasia and North America. We found that the genes that were positively selected in the early evolution of pikas were most concentrated in functional categories related to cold tolerance. These results suggest that the QTP may have served as a training ground for cold tolerance in early pikas, which gives pikas a great advantage when the climate continued to cool after the middle Miocene. Our study highlights the importance of the QTP as a center of origin for many cold-adapted animals.

3.
Front Med ; 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31950345

RESUMO

This study aimed to investigate the correlation between serum miR-154-5p and urinary albumin to creatinine ratio (UACR) in patients with type 2 diabetes mellitus (T2DM) and the association with biomarkers of inflammation and fibrosis in diabetic kidney disease (DKD). A total of 390 patients with T2DM were divided into three groups: normal albuminuria (UACR < 30 mg/g, n = 136, NA), microalbuminuria (UACR at 30-300 mg/g, n = 132, MA), and clinical albuminuria (UACR > 300 mg/g, n = 122, CA). Circulating miR-154-5p, inflammatory (C-reactive protein (CRP); erythrocyte sedimentation rate (ESR); and tumor necrosis factor-α (TNF-α) and fibrotic markers (vascular endothelial growth factor (VEGF); transforming growth factor-ß1 (TGF-ß1); and fibronectin (FN)), and other biochemical indicators were assessed via real-time PCR, enzyme-linked immunosorbent assay, and chemiluminescence assay in patients with T2DM and 138 control subjects (NC). UACR, miR-154-5p, glycated hemoglobin (HbA1c), serum creatinine (sCr), blood urea nitrogen (BUN), ESR, CRP, VEGF, TNF-α, TGF-ß1, and FN were significantly higher and the estimated glomerular filtration rate (eGFR) was significantly lower in NA, MA, and CA groups than in NC subjects (P < 0.05). Elevated levels of UACR and miR-154-5p were directly correlated with HbA1c, sCr, BUN, ESR, CRP, VEGF, TNF-α, TGF-ß1, and FN and negatively correlated with eGFR (P < 0.05). miR-154-5p, HbA1c, sCr, BUN, eGFR, ESR, CRP, VEGF, TNF-α, TGF-ß1, and FN were important factors affecting UACR. These findings indicated that elevated serum miR-154-5p is significantly correlated with high UACR in patients with T2DM and may offer a novel reference for the early diagnosis of DKD.

4.
Bull Environ Contam Toxicol ; 104(1): 149-155, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31784766

RESUMO

This study was intended to develop an environment-friendly controlled release system for spirotetramat in an alginate matrix. Four formulations, starch-chitosan-calcium alginate (SCCA), starch-calcium alginate (SCA), chitosan-calcium alginate (CCA), and calcium alginate (CA) complex gel beads, were prepared by the extrusion-exogenous gelation method. The properties of the formulations were studied. The results showed that the release behaviors of the formulations in water could be well described by the logistic model, and the release occurred through Fickian diffusion. Among the four formulations, SCCA showed the highest entrapment efficiency, drug loading and the slowest release rate. Degradation studies revealed that the SCCA formulation exhibited an obvious slower degradation rate of spirotetramat in soils than the commercially available formulation. The estimated half-life of the SCCA formulation was 2.31, 3.25, and 4.51 days in waterloggogenic paddy soil, purplish soil, and montmorillonite, respectively, when the soils were moistened to 60% of its dry weight. This study provided a possible approach to prolong the duration of spirotetramat and to reduce environmental contamination.

5.
Blood ; 135(1): 41-55, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31697823

RESUMO

To study the mechanisms of relapse in acute lymphoblastic leukemia (ALL), we performed whole-genome sequencing of 103 diagnosis-relapse-germline trios and ultra-deep sequencing of 208 serial samples in 16 patients. Relapse-specific somatic alterations were enriched in 12 genes (NR3C1, NR3C2, TP53, NT5C2, FPGS, CREBBP, MSH2, MSH6, PMS2, WHSC1, PRPS1, and PRPS2) involved in drug response. Their prevalence was 17% in very early relapse (<9 months from diagnosis), 65% in early relapse (9-36 months), and 32% in late relapse (>36 months) groups. Convergent evolution, in which multiple subclones harbor mutations in the same drug resistance gene, was observed in 6 relapses and confirmed by single-cell sequencing in 1 case. Mathematical modeling and mutational signature analysis indicated that early relapse resistance acquisition was frequently a 2-step process in which a persistent clone survived initial therapy and later acquired bona fide resistance mutations during therapy. In contrast, very early relapses arose from preexisting resistant clone(s). Two novel relapse-specific mutational signatures, one of which was caused by thiopurine treatment based on in vitro drug exposure experiments, were identified in early and late relapses but were absent from 2540 pan-cancer diagnosis samples and 129 non-ALL relapses. The novel signatures were detected in 27% of relapsed ALLs and were responsible for 46% of acquired resistance mutations in NT5C2, PRPS1, NR3C1, and TP53. These results suggest that chemotherapy-induced drug resistance mutations facilitate a subset of pediatric ALL relapses.

6.
Histopathology ; 76(2): 283-295, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31393622

RESUMO

AIMS: To investigate the relationship between adenoid basal carcinoma (ABC), adenoid cystic carcinoma (ACC) and squamous cell carcinoma (SCC) in the uterine cervix. METHODS AND RESULTS: We analysed the clinicopathological and molecular features in two pure ABCs, 15 SCCs with ABC-/ACC-like features and seven basaloid SCCs (BSCCs) by chart review, immunohistochemistry, human papillomavirus (HPV) RNA in-situ hybridisation and fluorescence in-situ hybridisation. All patients were alive with no evidence of disease, except for one patient with ACC-like features who died of disease at 18 months post diagnosis. The mixed carcinomas comprised variable SCCs and ABC-/ACC-like components displaying vague transitional zones. All components consistently showed diffuse p16, p63 and SOX2, variable cytokeratin (CK)7 and CK17 and rare Ber-EP4 and MYB expression; there was a substantially lower Ki67 index in pure ABCs and the ABC-like components. The ACC-like components showed no myoepithelial differentiation (SMA, calponin and S100) and MYB gene fusions. CK7, CK17 and Ber-EP4 were characteristically stronger in BSCCs than in the mixed carcinomas (P < 0.01). High-risk HPV (HR-HPV) E6/E7 mRNA was detected in 12 mixed carcinomas and seven BSCCs, but not in pure ABCs. The HR-HPV mRNA expression was higher in the SCC components and BSCCs than in the ABC-like components of mixed carcinomas (P < 0.05). CONCLUSIONS: The ACC-like components in mixed carcinomas probably represent the morphological mimics of salivary ACCs. ABC-like components may be the potential precursor of the ACC-like and SCC components. HR-HPV oncogenes may play a role in the pathogenesis of SCCs with ABC-/ACC-like features.

7.
Cancer Res Treat ; 52(1): 218-245, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31291711

RESUMO

PURPOSE: Anterior gradient 3 (AGR3) belongs to human anterior gradient (AGR) family. The function of AGR3 on cancer remains unknown. This research aimed to investigate if AGR3 had prognostic values in invasive ductal carcinoma (IDC) of breast cancer and could promote tumor progression. Materials and Methods: AGR3 expression was detected in breast benign lesions, ductal carcinoma in situ and IDC by immunohistochemistry analysis. AGR3's correlations with clinicopathological features and prognosis of IDC patients were analyzed. By cell function experiments, collagen gel droplet-embedded culture drug sensitivity test and cytotoxic analysis, AGR3's impacts on proliferation, invasion ability, and chemotherapeutic drug sensitivity of breast cancer cells were also detected. RESULTS: AGR3 was up-regulated in luminal subtype of histological grade I-II of IDC patients and positively correlated with high risks of recurrence and distant metastasis. AGR3 high expression could lead to bone or liver metastasis and predict poor prognosis of luminal B. In cell lines, AGR3 could promote proliferation and invasion ability of breast cancer cells which were consistent with clinical analysis. Besides, AGR3 could indicate poor prognosis of breast cancer patients treated with taxane but a favorable prognosis with 5-fluoropyrimidines. And breast cancer cells with AGR3 high expression were resistant to taxane but sensitive to 5-fluoropyrimidines. CONCLUSION: AGR3 might be a potential prognostic indicator in luminal B subtype of IDC patients of histological grade I-II. And patients with AGR3 high expression should be treated with chemotherapy regimens consisting of 5-fluoropyrimidines but no taxane.

8.
Redox Biol ; 28: 101322, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31605963

RESUMO

Homocysteine-Methionine (HM) cycle produces universal methyl group donor S-adenosylmethione (SAM), methyltransferase inhibitor S-adenosylhomocysteine (SAH) and homocysteine (Hcy). Hyperhomocysteinemia (HHcy) is established as an independent risk factor for cardiovascular disease (CVD) and other degenerative disease. We selected 115 genes in the extended HM cycle (31 metabolic enzymes and 84 methyltransferases), examined their protein subcellular location/partner protein, investigated their mRNA levels and mapped their corresponding histone methylation status in 35 disease conditions via mining a set of public databases and intensive literature research. We have 6 major findings. 1) All HM metabolic enzymes are located only in the cytosol except for cystathionine-ß-synthase (CBS), which was identified in both cytosol and nucleus. 2) Eight disease conditions encountered only histone hypomethylation on 8 histone residues (H3R2/K4/R8/K9/K27/K36/K79 and H4R3). Nine disease conditions had only histone hypermethylation on 8 histone residues (H3R2/K4/K9/K27/K36/K79 and H4R3/K20). 3) We classified 9 disease types with differential HM cycle expression pattern. Eleven disease conditions presented most 4 HM cycle pathway suppression. 4) Three disease conditions had all 4 HM cycle pathway suppression and only histone hypomethylation on H3R2/K4/R8/K9/K36 and H4R3. 5) Eleven HM cycle metabolic enzymes interact with 955 proteins. 6) Five paired HM cycle proteins interact with each other. We conclude that HM cycle is a key metabolic sensor system which mediates receptor-independent metabolism-associated danger signal recognition and modulates SAM/SAH-dependent methylation in disease conditions and that hypomethylation on frequently modified histone residues is a key mechanism for metabolic disorders, autoimmune disease and CVD. We propose that HM metabolism takes place in the cytosol, that nuclear methylation equilibration requires a nuclear-cytosol transfer of SAM/SAH/Hcy, and that Hcy clearance is essential for genetic protection.

9.
Redox Biol ; 28: 101373, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31731100

RESUMO

It has been shown that anti-inflammatory cytokines interleukin-35 (IL-35) and IL-10 could inhibit acute endothelial cell (EC) activation, however, it remains unknown if and by what pathways IL-35 and IL-10 could block atherogenic lipid lysophosphatidylcholine (LPC)-induced sustained EC activation; and if mitochondrial reactive oxygen species (mtROS) can differentiate mediation of EC activation from trained immunity (innate immune memory). Using RNA sequencing analyses, biochemical assays, as well as database mining approaches, we compared the effects of IL-35 and IL-10 in LPC-treated human aortic ECs (HAECs). Principal component analysis revealed that both IL-35 and IL-10 could similarly and partially reverse global transcriptome changes induced by LPC. Gene set enrichment analyses showed that while IL-35 and IL-10 could both block acute EC activation, characterized by upregulation of cytokines/chemokines and adhesion molecules, IL-35 is more potent than IL-10 in suppressing innate immune signatures upregulated by LPC. Surprisingly, LPC did not induce the expression of trained tolerance itaconate pathway enzymes but induced trained immunity enzyme expressions; and neither IL-35 nor IL-10 was found to affect LPC-induced trained immunity gene signatures. Mechanistically, IL-35 and IL-10 could suppress mtROS, which partially mediate LPC-induced EC activation and innate immune response. Therefore, anti-inflammatory cytokines could reverse mtROS-mediated acute and innate immune trans-differentiation responses in HAECs, but it could spare metabolic reprogramming and trained immunity signatures, which may not fully depend on mtROS. Our characterizations of anti-inflammatory cytokines in blocking mtROS-mediated acute and prolonged EC activation, and sparing trained immunity are significant for designing novel strategies for treating cardiovascular diseases, other inflammatory diseases, and cancers.

10.
Mol Cell Endocrinol ; 500: 110628, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31647955

RESUMO

Metformin, as the basic pharmacological therapy and the first preventive drug in type 2 diabetes mellitus (T2DM), is proved to have potential protection in diabetic kidney disease (DKD). Here, we established a diabetic rat model induced by high-fat diet and low dose streptozotocin, and high glucose cultured rat mesangial cells (RMCs) pre-treated with metformin or transfected with AMPK, SIRT1 and FoxO1 small interfering RNA, and detected oxidative stress and autophagy related factors to explore the molecular mechanisms of metformin on DKD via adenosine monophosphate-activated protein kinase (AMPK)/silent mating type information regulation 2 homolog-1 (sirtuin-1, SIRT1)-Forkhead box protein O1 (FoxO1) pathway. We found that metformin effectively alleviated the disorders of glycolipid metabolism, renal function injury in diabetic rats, and relieved oxidative stress, enhanced autophagy and slowed down abnormal cell proliferation in high glucose cultured RMCs through AMPK/SIRT1-FoxO1 pathway, indicating the protective role of metformin against the pathological process of DKD.

11.
Front Immunol ; 10: 2612, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31824480

RESUMO

The mechanisms underlying pathophysiological regulation of tissue macrophage (Mφ) subsets remain poorly understood. From the expression of 207 Mφ genes comprising 31 markers for 10 subsets, 45 transcription factors (TFs), 56 immunometabolism enzymes, 23 trained immunity (innate immune memory) enzymes, and 52 other genes in microarray data, we made the following findings. (1) When 34 inflammation diseases and tumor types were grouped into eight categories, there was differential expression of the 31 Mφ markers and 45 Mφ TFs, highlighted by 12 shared and 20 group-specific disease pathways. (2) Mφ in lung, liver, spleen, and intestine (LLSI-Mφ) express higher M1 Mφ markers than lean adipose tissue Mφ (ATMφ) physiologically. (3) Pro-adipogenic TFs C/EBPα and PPARγ and proinflammatory adipokine leptin upregulate the expression of M1 Mφ markers. (4) Among 10 immune checkpoint receptors (ICRs), LLSI-Mφ and bone marrow (BM) Mφ express higher levels of CD274 (PDL-1) than ATMφ, presumably to counteract the M1 dominant status via its reverse signaling behavior. (5) Among 24 intercellular communication exosome mediators, LLSI- and BM- Mφ prefer to use RAB27A and STX3 than RAB31 and YKT6, suggesting new inflammatory exosome mediators for propagating inflammation. (6) Mφ in peritoneal tissue and LLSI-Mφ upregulate higher levels of immunometabolism enzymes than does ATMφ. (7) Mφ from peritoneum and LLSI-Mφ upregulate more trained immunity enzyme genes than does ATMφ. Our results suggest that multiple new mechanisms including the cell surface, intracellular immunometabolism, trained immunity, and TFs may be responsible for disease group-specific and shared pathways. Our findings have provided novel insights on the pathophysiological regulation of tissue Mφ, the disease group-specific and shared pathways of Mφ, and novel therapeutic targets for cancers and inflammations.

12.
Artigo em Inglês | MEDLINE | ID: mdl-31818950

RESUMO

Loss of function of CDKN2A/B, also known as INK4/ARF [encoding p16INK4A, p15INK4B, and p14ARF (mouse p19Arf)], confers susceptibility to cancers, whereas its up-regulation during organismal aging provokes cellular senescence and tissue degenerative disorders. To better understand the transcriptional regulation of p16 INK4A , a CRISPR screen targeting open, noncoding chromatin regions adjacent to p16 INK4A was performed in a human p16 INK4A-P2A-mCherry reporter cell line. We identified a repressive element located in the 3' region adjacent to the ARF promoter that controls p16 INK4A expression via long-distance chromatin interactions. Coinfection of lentiviral dCas9-KRAB with selected single-guide RNAs against the repressive element abrogated the ARF/p16 INK4A chromatin contacts, thus reactivating p16 INK4A expression. Genetic CRISPR screening identified candidate transcription factors inhibiting p16 INK4A regulation, including ZNF217, which was confirmed to bind the ARF/p16 INK4A interaction loop. In summary, direct physical interactions between p16 INK4A and ARF genes provide mechanistic insights into their cross-regulation.

13.
Huan Jing Ke Xue ; 40(7): 3331-3338, 2019 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854735

RESUMO

The remediation of cadmium (Cd) contaminated paddy soils has become an important issue in the field of remediation of agricultural soils contaminated by heavy metals. The iron (Fe) redox cycle (referring to the fluctuation of iron between the ferrous (Ⅱ) and ferric (Ⅲ) oxidation states) exhibits a unique role in the transportation of Cd in the soil-rice system. The exploration of practical remediation strategies for Cd from the perspective of the Fe redox cycle is expected to obtain some state-of-the-art technologies and products to reduce Cd accumulation in rice grains. In this study, an amendment was selected and a field experiment was carried out to investigate the effects of this amendment on Cd transportation from the rhizosphere soil to the Fe plaque, and further to different rice tissues at four different growth stages, and to highlight some possible mechanisms by which the Fe redox cycle controls Cd availability in rice paddy fields. The results showed that the amendment induced the formation of Fe sulfides, which co-precipitated with Cd, reducing the NH4Ac-extractable Cd content in rhizosphere soils at the tillering, jointing, and filling stages; the oxidation of Fe sulfides increased the NH4Ac-extractable Cd content in the rhizosphere soil at the maturing stage; the formation of Fe sulfides in rhizosphere soils impeded the migration of Fe(Ⅱ) from the rhizosphere soil to the root surface, decreasing the content of DCB-extractable Fe and Cd in Fe plaques at the tillering and filling stages; the amendment inhibited Cd transportation from the roots to other tissues, increasing the proportion of Cd in the roots at the jointing, filling, and maturing stages, but decreasing the proportion in the straws at the jointing, filling, and maturing stages, and in the rice grain at the maturing stage. These findings provide a theoretical basis for the exploration and application of the amendment, and have significance in the field of remediation of Cd-contaminated paddy soils.


Assuntos
Cádmio/química , Ferro/química , Oryza , Rizosfera , Poluentes do Solo/química
15.
J Craniofac Surg ; 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31688261

RESUMO

BACKGROUND: Published reports describing management of complex facial lacerations in the emergency department are limited, and there is little guidance on the treatment of massive soft tissue avulsions of the head and face or severely contaminated head and face lacerations. Here, the authors report on the wealth of clinical experience they have gained in treating major head and facial injuries through an emergency trauma repair platform that was established in the department of orthopedic surgery at their hospital. METHODS: Six patients with massive soft tissue avulsions of the head and face caused by trauma were treated in our department between September 2017 and December 2018. Avulsion injuries occurred to the eyelids, ears, face, and part of the scalp. Defects extended from the skin to the surface of the bone. Emergency surgical repair involved reasonable debridement of the wound surface, accurate and meticulous suture, and use of local skin flaps. RESULTS: No patients experienced postoperative complications, such as necrosis, infection, or scar hyperplasia. Our postoperative satisfaction survey showed that 3 patients were very satisfied and 1 patient was relatively satisfied with their outcomes. Several patients (2/6) still had some degree of deformity in the soft tissue around the eyes, which required further surgery CONCLUSION:: Satisfactory functional and aesthetic outcomes can be achieved through reasonable debridement of the wound surface, accurate and meticulous suture, and use of local skin flaps in patients with massive soft tissue avulsions of the head and face caused by trauma.

16.
Org Lett ; 21(22): 9050-9054, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31691566

RESUMO

A gold-catalyzed oxy-propargylamination of N-allenamides has been developed by using C-alkynyl N-Boc-acetals as the difunctionalization reagents. Typically, this process features the unique proximal addition rather than the common distal nucleophilic addition for gold(I)-activated allenamides. This reaction is atom-economic and provides highly functionalized 1,3-amino alcohol derivatives in good yields with good to excellent diastereoselectivities under mild reaction conditions.

17.
Lasers Surg Med ; 2019 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-31736126

RESUMO

BACKGROUND AND OBJECTIVES: To investigate the effects of percutaneous interstitial Nd:YAG laser irradiation on the apocrine glands and molecules involved in odor production (apolipoprotein [ApoD], androgen receptor [AR]) in the subcutaneous tissue of a pig. STUDY DESIGN/MATERIALS AND METHODS: Skin on the back of healthy adult miniature pigs was exposed to pulsed Nd:YAG laser irradiation at 5 or 10 W, or continuous Nd:YAG laser irradiation at 10 W. Samples were taken 1 hour, 1 week, and 1 month after treatment for histology, western blot, and real-time quantitative polymerase chain reaction (qRT-PCR) analysis. RESULTS: One week and 1 month after irradiation, the apocrine glands in pigskin became rounded, glandular cells were shorter, and the glandular cavities were larger compared with controls, but there were no obvious changes in fat cell distribution of collagen around the apocrine glands. One month after irradiation at 10 W in continuous mode, there was a significant decrease in ApoD expression in apocrine cells and ApoD and AR protein and expression levels in pigskin compared with controls. There were also significant differences in ApoD and AR protein and expression levels between treatments. CONCLUSIONS: Percutaneous interstitial Nd:YAG laser irradiation has potential as a safe and efficacious treatment for axillary osmidrosis as it may decrease the production of volatile unsaturated fatty acids, steroids, and associated unpleasant odors in the axilla. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

19.
Org Lett ; 21(22): 9076-9079, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31657937

RESUMO

A copper-catalyzed 1,2-difunctionalization of ynamides has been developed by using readily available N,O-acetals as the bifunctional reagents. Importantly, contrary to the initially expected 1,2-oxy-aminomethylation reaction, an unprecedented 1,2-amino-oxymethylation has been observed. This reaction is atom-economical and tolerates a broad substrate scope, affording the difunctionalization products in good yield with unique Z configuration.

20.
Org Lett ; 21(20): 8488-8491, 2019 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-31596104

RESUMO

A catalyst-controlled selective functionalization of indoles with vinyl diazoacetates has been developed. The use of gold catalysts exclusively leads to C3-alkylation products, whereas the highly diastereoselective cyclopropanation reaction is dominant for silver catalysis. Importantly, the gold and silver vinylcarbenes exhibit highly carbenic rather than vinylogous reactivity in these transformations.

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