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1.
Bioresour Technol ; 376: 128910, 2023 May.
Article in English | MEDLINE | ID: mdl-36940875

ABSTRACT

Glutathione, a tri-peptide (glutamate-cysteine-glycine) with the thiol group (-SH), is most efficient antioxidative agent in eukaryotic cells. The present study aimed to isolate an efficient probiotic bacterium having the potential to produce glutathione. The isolated strain Bacillus amyloliquefaciens KMH10 showed antioxidative activity (77.7 ± 2.56) and several other essential probiotic attributes. Banana peel, a waste of banana fruit, is chiefly composed of hemicellulose with various minerals and amino acids. A consortium of lignocellulolytic enzyme was used for the saccharifying banana peel to produce 65.71 g/L sugar to support the optimal glutathione production of 181 ± 4.56 mg/L; i.e., 1.6 folds higher than the control. So, the studied probiotic bacteria could be an effective resource for glutathione; therefore, the stain could be used as natural therapeutics for the prevention/treatment of different inflammation-related gastric ailments and as an effective producer of glutathione using valorized banana waste that has excellent industrial relevance.


Subject(s)
Bacillus amyloliquefaciens , Musa , Probiotics , Musa/chemistry , Antioxidants/chemistry , Glutathione
2.
Ther Adv Neurol Disord ; 16: 17562864221149781, 2023.
Article in English | MEDLINE | ID: mdl-36710722

ABSTRACT

Background: Adeno-associated virus (AAV) vectors are a promising platform for in vivo transfer of transgenes designed to treat diseases. Pre-existing humoral immunity to these vectors can potentially impact the safety and efficacy of gene therapies. Consequently, individuals with pre-existing antibodies to the specific AAV serotypes used may be excluded from clinical trials and treatments. Recombinant AAV serotype rh74 (rAAVrh74), a vector originally isolated from rhesus monkeys and potentially less immunogenic than other serotypes isolated from humans (e.g. AAV2, AAV5, and AAV9), efficiently transduces muscle and is being investigated for use in gene therapy for Duchenne muscular dystrophy (DMD). Objective: To evaluate prevalence of total binding antibodies (neutralizing and non-neutralizing) against rAAVrh74 in patients with DMD. Methods: Eligible individuals (N = 107) were ⩾ 4 to < 18 years old with genetically confirmed DMD and were excluded from the study if they lived with a person who had known exposure to rAAVrh74 or other gene transfer therapy, or if they received prior treatment with gene transfer therapy. A single blood sample was obtained from each participant, and anti-rAAVrh74 total binding antibodies were measured by enzyme-linked immunosorbent assay. Total binding antibody level < 1:400 was defined as not elevated or seronegative. Primary endpoint was the percentage of subjects with elevated total antibody titers to rAAVrh74. Results: A large preponderance (86.1%) of patients with DMD in this data set was seronegative for anti-rAAVrh74 total binding antibodies. These patients would potentially meet the antibody status eligibility criterion for entry into rAAVrh74-based gene therapy clinical trials. Conclusion: Measuring total binding antibodies is a more comprehensive approach to assess pre-existing immune response versus measuring neutralizing antibodies alone. The low seroprevalence of total binding antibodies against rAAVrh74 shown here supports the broad applicability of rAAVrh74-based gene transfer therapy for patients with DMD and potentially other neuromuscular diseases.

3.
J Trace Elem Med Biol ; 77: 127133, 2023 May.
Article in English | MEDLINE | ID: mdl-36638706

ABSTRACT

BACKGROUND: Chronic fluoride toxicity induces oxidative strain and lipid peroxidation and imparts deleterious effects on human metabolic organs. AIM: The present study aimed to expose the defensive impact of ferulic acid against sodium fluoride (NaF) induced hepatorenal dysfunction at the biochemical and antioxidative systems. METHODS: In-vivo. Rats were arbitrarily separated into five groups as control, sodium fluoride-treated (200 ppm kg -1), vitamin C -as a positive control, and FA co-administered groups with 10 mg kg -1 and 20 mg kg -1 body weight for 56 days. In the present investigation, we measured antioxidant enzymes, superoxide dismutase, catalase, and lactate dehydrogenase by electrozymographic and spectrophotometric methods. Biochemical assessment of TBARS, conjugated diene, and different serum biomarkers was done for liver and kidney functionality tests. In-silico. An in-silico study was conducted through a molecular docking experiment to evaluate the binding potentiality of FA by employing AutoDock Vina [version 1.5.6] to overcome the abnormality in the activities of catalase, and superoxide dismutase in NaF promoted toxicity of hepatorenal system. In-vitro. An in vitro biochemical experiment was conducted to support the in-silico study. RESULTS: Superoxide dismutase and catalase were decreased in the intoxicated rat. Ferulic acid (FA) as an antioxidant remarkably defended the NaF-mediated deterioration of the antioxidative status in the hepatorenal system, lowering lipid peroxidation products, malondialdehyde, and conjugated diene. Serum biomarkers, ALT, AST, ALP, urea, and creatinine increased in the intoxicated group than in control. Ferulic acid significantly neutralized the ill effects of NaF on serum lipid profile. In-silico analysis hypothesized the strong interaction of FA with the active side of catalase and superoxide dismutase that prevented the binding of NaF at the active site of these mentioned enzymes and this was further validated by in-vitro assay. CONCLUSION: However, FA modulates free radical generation and protected these metabolic organs against sodium fluoride-induced injury.


Subject(s)
Antioxidants , Fluorides , Humans , Rats , Animals , Antioxidants/metabolism , Catalase/metabolism , Fluorides/pharmacology , Sodium Fluoride/pharmacology , Molecular Docking Simulation , Glutathione/metabolism , Rats, Wistar , Oxidative Stress , Liver/metabolism , Superoxide Dismutase/metabolism , Biomarkers/metabolism , Lipid Peroxidation
4.
J Agric Food Chem ; 70(25): 7662-7673, 2022 Jun 29.
Article in English | MEDLINE | ID: mdl-35699309

ABSTRACT

The present study represented an innovative strategy for inactivating the secreted invasins (lignocellulolytic enzymes) of fungal phytopathogens using natural phytochemicals to combat fungal infection to the pulses. A fungal pathogen (Aspergillus niger SKP1) was isolated from the white lentil (Vigna mungo), which has the ability to synthesize different lignocellulolytic enzymes. An in silico docking study elucidated that quercetin, naringin, epigallocatechin gallate, curcumin, and cinnamic acid were the prime efficient phytochemicals to inhibit the activity of fungal invasive enzymes like endoglucanase, endo-1,4-ß-xylanase, and glucoamylase. Considering this observation, extracted phytochemicals in different mixtures were applied to prevent growth of the isolated pathogen under in situ experimental studies. The minimal inhibitory concentrations (MIC50) and minimal fungicidal concentration (MFC50) values of the first mixture (naringenin, epicatechin gallate, and cinnamic acid) and second mixture (quercetin and curcumin) were 170 and 220 mg/L and 320 and 380 mg/L, respectively. The studied phytochemicals were established to be cytosafe when compared to the commercial fungicides. The seeds of the white lentil were subjected to 1 year of long-term storage with the two aforementioned combinatorial phytochemicals. Subsequent morphological and physiological analyses revealed the complete protection of the stored seeds from the fungal infection. The present work has enough potentiality for the storage of pulses using natural preservatives that circumvent the adverse effect of the chemical preservatives on the ecosystem.


Subject(s)
Curcumin , Quercetin , Aspergillus niger , Curcumin/pharmacology , Ecosystem , Phytochemicals/pharmacology , Quercetin/pharmacology
5.
Front Microbiol ; 13: 794503, 2022.
Article in English | MEDLINE | ID: mdl-35607594

ABSTRACT

The present study has been aimed at evaluating the antiobesity, antihyperglycemic, and antidepressive potentials of Asparagus racemosus starter-based rice fermented foods. High-throughput NGS technology has revealed a number of bacterial genera in the prepared fermented rice, such as Lactobacillus (29.44%), Brevundimonas (16.21%), Stenotrophomonas (6.18%), Pseudomonas (3.11%), Bacillus (2.88%), and others (<2%). Eight-week administration of rice fermented food has increased food intake, whole-body weight, organ weight, different fat masses, serum lipid profiles, and histology of liver and adipose tissues in HFD-induced obese mice. In addition, upregulation of fatty acid oxidation and downregulation of adipocytogenesis- and lypogenesis-related genes along with the expression of their regulatory nuclear factors such as PPARα, PPARγ, PPARδ, and SREBP-1c have also been noted. Moreover, fermented food decreases fasting blood glucose level and improves glucose and insulin tolerance as well as the expression of GLUT4 receptor. Antiobesity and antihyperglycemic effects are also supported by the changes in insulin, leptin, and adiponectin hormone levels. The real-time polymerase chain reaction (RT-PCR) and denaturing gradient gel electrophoresis (DGGE) analyses have clearly demonstrated the intense colonization of Bacteroides, Lactobacillus, and Bifidobacterium, as well as the suppressed growth rate of γ- and δ-Proteobacteria and Firmicutes in the gut after fermented food intake. In the intestine, the latter group of microorganisms possibly modulate short-chain fatty acid (SCFA) levels such as acetate, butyrate, and propionate more than twofold. The impairment of memory-learning and anxiety-like obesity-associated cognitive phenotypes is mitigated significantly (p < 0.01) by fermented food as well. Thus, the formulated fermented food could be used as a natural therapeutic to alleviate obesity and its associated psychological and pathophysiological ailments.

6.
Bioresour Technol ; 343: 126093, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34624476

ABSTRACT

A multistep approach was undertaken for biobutanol production targeting valorization of agricultural waste. Optimum production of lignocellulolytic enzymes [CMCase (3822.93U/mg), FPase (3640.93U/mg), ß-glucosidase (3873.92U/mg), xylanase (3460.24U/mg), pectinase (3359.57U/mg), α-amylase (4136.54U/mg), and laccase (3863.16U/mg)] was accomplished through solid-substrate fermentation of pretreated mixed substrates (wheat bran, sugarcane bagasse and orange peel) by Aspergillus niger SKN1 and Trametes hirsuta SKH1. Partially purified enzyme cocktail was employed for saccharification of the said substrate mixture into fermentable sugar (69.23 g/L, product yield of 24% w/w). The recovered sugar with vegetable extract supplements was found as robust fermentable medium that supported 16.51 g/L biobutanol production by Clostridium acetobutylicum ATCC824. The sequential bioprocessing of low-priced substrates and exploitation of vegetable extract as growth factor for microbial butanol production will open a new vista in biofuel research.


Subject(s)
Clostridium acetobutylicum , Biomass , Butanols , Fermentation , Hydrolysis , Lignin , Polyporaceae , Trametes
7.
J Neuromuscul Dis ; 9(1): 39-52, 2022.
Article in English | MEDLINE | ID: mdl-34420980

ABSTRACT

BACKGROUND: Studies 4658-201/202 (201/202) evaluated treatment effects of eteplirsen over 4 years in patients with Duchenne muscular dystrophy and confirmed exon-51 amenable genetic mutations. Chart review Study 4658-405 (405) further followed these patients while receiving eteplirsen during usual clinical care. OBJECTIVE: To compare long-term clinical outcomes of eteplirsen-treated patients from Studies 201/202/405 with those of external controls. METHODS: Median total follow-up time was approximately 6 years of eteplirsen treatment. Outcomes included loss of ambulation (LOA) and percent-predicted forced vital capacity (FVC%p). Time to LOA was compared between eteplirsen-treated patients and standard of care (SOC) external controls and was measured from eteplirsen initiation in 201/202 or, in the SOC group, from the first study visit. Comparisons were conducted using univariate Kaplan-Meier analyses and log-rank tests, and multivariate Cox proportional hazards models with regression adjustment for baseline characteristics. Annual change in FVC%p was compared between eteplirsen-treated patients and natural history study patients using linear mixed models with repeated measures. RESULTS: Data were included from all 12 patients in Studies 201/202 and the 10 patients with available data from 405. Median age at LOA was 15.16 years. Eteplirsen-treated patients experienced a statistically significant longer median time to LOA by 2.09 years (5.09 vs. 3.00 years, p < 0.01) and significantly attenuated rates of pulmonary decline vs. natural history patients (FVC%p change: -3.3 vs. -6.0 percentage points annually, p < 0.0001). CONCLUSIONS: Study 405 highlights the functional benefits of eteplirsen on ambulatory and pulmonary function outcomes up to 7 years of follow-up in comparison to external controls.


Subject(s)
Disease Progression , Mobility Limitation , Morpholinos/pharmacology , Muscular Dystrophy, Duchenne/drug therapy , Muscular Dystrophy, Duchenne/physiopathology , Outcome Assessment, Health Care , Registries , Adolescent , Child , Humans , Male , Morpholinos/administration & dosage , Prospective Studies , Retrospective Studies , Time Factors , Vital Capacity , Walk Test
8.
Angew Chem Int Ed Engl ; 60(22): 12406-12412, 2021 05 25.
Article in English | MEDLINE | ID: mdl-33621382

ABSTRACT

Amino acid and peptide couplings are widely used in fields related to pharma and materials. Still, current peptide synthesis continues to rely on the use of expensive, water sensitive, and waste-generating coupling reagents, which are often prepared in multi-step sequences and used in excess. Herein is described a peptide coupling reaction design that relies mechanistically on sun-light activation of a 4-dimethylamino-pyridine-alkyl halide charge-transfer complex to generate a novel coupling reagent in situ. The resulting coupling method is rapid, does not require dry solvents or inert atmosphere, and is compatible with all the most common amino acids and protecting groups. Peptide couplings can be run on gram-scale, without the use of special equipment. This method has a significantly reduced environmental and financial footprint compared to standard peptide coupling reactions. Experimental and computational studies support the proposed mechanism.

9.
J Org Chem ; 86(1): 1164-1171, 2021 Jan 01.
Article in English | MEDLINE | ID: mdl-33236899

ABSTRACT

We report a visible-light-mediated benzylic C-H oxygenation reaction. The reaction is initiated by solar light or the blue LED activation of 9,10-dibromoanthracene in a reaction with oxygen and takes place at ambient temperature and air pressure. Secondary benzylic positions are oxygenated to ketones, while tertiary benzylic carbons are oxygenated to give hydroperoxides. Notably, cumene hydroperoxide is produced in a higher yield and at milder conditions than the currently employed industrial conditions.

10.
BMJ Open ; 10(10): e038861, 2020 10 20.
Article in English | MEDLINE | ID: mdl-33082194

ABSTRACT

OBJECTIVE: To directly compare the efficacy of natalizumab and fingolimod in patients with active relapsing-remitting multiple sclerosis. METHODS: This phase 4, randomised, rater- and sponsor-blinded, prospective, parallel-group, clinic-based head-to-head study was conducted at 43 sites in nine countries. Patients were randomised (1:1) to intravenous natalizumab 300 mg every 4 weeks or oral fingolimod 0.5 mg once daily for ≤52 weeks. Enrolment-related early study termination precluded assessment of the primary endpoint (evolution of new on-treatment gadolinium-enhancing (Gd+) lesions to persistent black holes). Unplanned exploratory analyses of secondary endpoints evaluated the effects of treatment on the development of new T1 Gd+ lesions and new/newly enlarging T2 lesions, lesion volumes and relapse outcomes. RESULTS: The intent-to-treat population comprised 108 patients (natalizumab, n=54; fingolimod, n=54); 63 completed ≥24 weeks of treatment. Due to the limited numbers of events and patients at risk, MRI and relapse outcomes were reported over up to 24 and 36 weeks, respectively. The mean number of new T1 Gd+ lesions was numerically lower with natalizumab than with fingolimod by 4 weeks; accumulation rates were 0.02 and 0.09 per week, respectively, over 24 weeks (p=0.004). The cumulative probability of developing ≥1 lesion at 24 weeks was 40.7% with natalizumab versus 58.0% with fingolimod (HR=0.60; 95% CI 0.31-1.16; p=0.126); the corresponding probabilities for ≥2 lesions were 11.5% vs 48.5% (HR=0.25; 95% CI 0.09-0.68; p=0.007). No significant between-group differences were observed for the other MRI outcomes at 24 weeks. The cumulative probability of relapse over follow-up was 1.9% with natalizumab versus 22.3% with fingolimod (HR=0.08; 95% CI 0.01-0.64; p=0.017). Adverse events were consistent with known safety profiles. CONCLUSIONS: These results suggest that natalizumab is more efficacious than fingolimod in reducing multiple sclerosis relapses and T1 Gd+ lesion accumulation in patients with active disease. TRIAL REGISTRATION NUMBERS: NCT02342704; EUCTR2013-004622-29-IT; Post-results.


Subject(s)
Multiple Sclerosis, Relapsing-Remitting , Multiple Sclerosis , Fingolimod Hydrochloride/therapeutic use , Humans , Immunosuppressive Agents/adverse effects , Multiple Sclerosis, Relapsing-Remitting/diagnostic imaging , Multiple Sclerosis, Relapsing-Remitting/drug therapy , Natalizumab/adverse effects , Prospective Studies , Treatment Outcome
11.
Angew Chem Int Ed Engl ; 59(35): 15171-15175, 2020 08 24.
Article in English | MEDLINE | ID: mdl-32394609

ABSTRACT

Herein we report on the umpolung of Morita-Baylis-Hillman type intermediates and application to the α-functionalization of enone C-H bonds. This reaction gives direct access to α-chloro-enones, 1,2-diketones and α-tosyloxy-enones. The latter are important intermediates for cross-coupling reaction and, to the best of our knowledge, cannot be made in a single step from enones in any other way. The proposed mechanism is supported by spectroscopic studies. The key initial step involves conjugate attack of an amine (DABCO or pyridine), likely assisted by hypervalent iodine acting as a Lewis acid leading to formation of an electrophilic ß-ammonium-enolonium species. Nucleophilic attack by acetate, tosylate, or chloride anion is followed by base induced elimination of the ammonium species to give the noted products. Hydrolysis of α-acetoxy-enones lead to formation of 1,2-diketones. The α-tosyl-enones participate in Negishi coupling reactions under standard conditions.

12.
Org Lett ; 22(3): 768-771, 2020 Feb 07.
Article in English | MEDLINE | ID: mdl-31916772

ABSTRACT

Vinyl azides react with boron trifluoride activated Koser's hypervalent iodine reagent to afford azido-enolonium species. These previously unknown azido-enolonium species react efficiently with aromatic compounds, allyltrimethylsilane, and azoles under mild conditions, with no need for a transition-metal catalyst, forming C-C and C-N bonds to give a variety of α-functionalized ketones. The intermediacy of the proposed azido-enolonium species is supported by spectroscopic studies.

13.
BMC Neurol ; 19(1): 116, 2019 Jun 08.
Article in English | MEDLINE | ID: mdl-31176355

ABSTRACT

BACKGROUND: STRIVE is a multicenter, observational, open-label, single-arm study of natalizumab in anti-JC virus (JCV) seronegative patients with early relapsing-remitting multiple sclerosis (RRMS). The objective of this prespecified 2-year interim analysis was to determine the effectiveness of natalizumab in establishing and maintaining no evidence of disease activity (NEDA) in early RRMS. METHODS: Patients aged 18-65 years had an RRMS diagnosis < 3 years prior to screening, an Expanded Disability Status Scale (EDSS) score ≤ 4.0, and anti-JCV antibody negative status. Magnetic resonance imaging was performed at baseline and yearly thereafter. Cumulative probabilities of 24-week-confirmed EDSS worsening and improvement were evaluated at 2 years. NEDA (no 24-week-confirmed EDSS worsening, no relapses, no gadolinium-enhancing lesions, and no new/newly enlarging T2-hyperintense lesions) was evaluated over 2 years. The Symbol Digit Modalities Test (SDMT) and Multiple Sclerosis Impact Score (MSIS-29) were assessed at baseline and 1 and 2 years. Statistical analysis used summary statistics and frequency distributions. RESULTS: The study population (N = 222) had early RRMS, with mean (standard deviation [SD]) time since diagnosis of 1.6 (0.77) years and mean (SD) baseline EDSS score of 2.0 (1.13). NEDA was achieved in 105 of 187 patients (56.1%) during year 1 and 120 of 163 (73.6%) during year 2. Over 2 years, 76 of 171 patients (44.4%) attained overall NEDA. Probabilities of 24-week-confirmed EDSS worsening and improvement were 14.1% and 28.4%, respectively. After 2 years, patients exhibited significant improvements from baseline in SDMT (n = 158; mean [SD]: 4.3 [11.8]; p < 0.001) and MSIS-29 physical (n = 153; mean [SD]: - 3.9 [14.7]; p = 0.001), psychological (n = 152; mean [SD]: - 2.0 [7.9]; p < 0.001), and quality-of-life (n = 153; mean [SD]: - 6.0 [21.3]; p < 0.001) scores. CONCLUSIONS: These results support natalizumab's effectiveness over 2 years, during which nearly half of early RRMS patients achieved NEDA. During year 2, nearly 75% of patients exhibited NEDA. Over 2 years, patients continued to experience significant cognitive and quality-of-life benefits. These results are limited by the lack of a comparator group to determine the extent of a placebo effect. TRIAL REGISTRATION: clinicaltrials.gov, NCT01485003 , registered 5 December 2011.


Subject(s)
Immunologic Factors/pharmacology , Multiple Sclerosis, Relapsing-Remitting/drug therapy , Natalizumab/pharmacology , Outcome Assessment, Health Care , Adult , Female , Humans , Immunologic Factors/administration & dosage , Male , Middle Aged , Natalizumab/administration & dosage , Time Factors
14.
CNS Drugs ; 32(12): 1183, 2018 12.
Article in English | MEDLINE | ID: mdl-30244406

ABSTRACT

An Online First version of this article was made available online at http://link.springer.com/journal/40263/onlineFirst/page/1 on 24 August 2018. An error was subsequently identified in the article, and the following correction should be noted.

15.
CNS Drugs ; 32(12): 1173-1181, 2018 12.
Article in English | MEDLINE | ID: mdl-30143944

ABSTRACT

BACKGROUND: Cognitive impairment affects many patients with multiple sclerosis (MS). NeuroTrax, a computerized cognitive screen that can be administered during routine clinical care, provides a consistent, validated, objective cognitive profile measure with a global cognitive score (GCS) and seven individual domain scores. Natalizumab is an efficacious therapy for relapsing MS, demonstrating reductions in disability worsening and MS disease activity measured by magnetic resonance imaging. OBJECTIVE: The aim of this study was to assess cognitive function as measured by NeuroTrax in MS patients treated with natalizumab for ≥ 2 years. METHODS: This retrospective observational study included adult MS patients in the United States who received 300 mg intravenous natalizumab every 4 weeks for ≥ 2 years. NeuroTrax data were evaluated at baseline and yearly thereafter. Changes in GCS and the seven individual cognitive domain scores from baseline to after 24 infusions of natalizumab were analyzed. RESULTS: In the study population at baseline (N = 52), 22 patients (42.3%) had disease duration of 0-5 years; 12 patients (23.1%) were treatment naive. GCS score improved significantly from baseline [mean 95.5, standard deviation (SD) 12.9] to year 2 (mean 98.9, SD 13.2; change from baseline 3.4; p = 0.003). After 2 years on natalizumab, 17 patients (32.7%) demonstrated clinically significant improvement (increase from baseline > 1 SD) in GCS. Results were similar regardless of whether patients had previously received MS therapy. CONCLUSIONS: Patients treated with natalizumab demonstrated significant improvement in cognitive function, measured by NeuroTrax GCS, over 2 years of treatment.


Subject(s)
Cognition Disorders/drug therapy , Cognition Disorders/etiology , Immunologic Factors/therapeutic use , Multiple Sclerosis, Relapsing-Remitting/complications , Natalizumab/therapeutic use , Neuropsychological Tests , Adult , Disability Evaluation , Female , Humans , Male , Middle Aged , Multiple Sclerosis, Relapsing-Remitting/drug therapy , Retrospective Studies , Time Factors , Treatment Outcome , United States
16.
J Org Chem ; 82(12): 6358-6365, 2017 06 16.
Article in English | MEDLINE | ID: mdl-28521105

ABSTRACT

A sequential construction of C-C, C-O, C═N, and C═O bonds from alkenes leading to the direct synthesis of isoxazolines in the presence of tert-butyl nitrite, quinoline, and the Sc(OTf)3 catalyst in DCE at 80 °C has been accomplished. An unprecedented three consecutive C-H functionalizations of two styrenes are involved in this isoxazoline synthesis. In this radical-mediated reaction, one-half of the aryl alkene is converted into an intermediate 2-nitroketone, which serves as a 1,3-dipolarophile and undergoes cycloaddition with the other half of the unreacted aromatic terminal alkene. The use of an alkyne in lieu of an alkene leads to the formation of isoxazole under identical reaction conditions.

17.
J Org Chem ; 81(14): 6066-74, 2016 07 15.
Article in English | MEDLINE | ID: mdl-27314648

ABSTRACT

A Pd(II)-catalyzed peroxide-free ortho aroylation of directing arenes has been developed via cross dehydrogenative coupling (CDC) in the presence of the terminal oxidant Cu(OAc)2·H2O. Ortho aroylation of directing arenes proceeds via decarbonylation of the in situ generated phenyl glyoxal, which is obtained from 2-acetoxyacetophenone in the presence of the oxidant Cu(OAc)2·H2O. However, changing the oxidant to CuX2 (X = Cl, Br) provided exclusive di-ortho-halogenated 2-arylbenzothiazoles. During the halogenation, CuX2 served the dual role of a halogen source as well as a co-oxidant.

18.
Chem Commun (Camb) ; 52(24): 4501-4, 2016 Mar 25.
Article in English | MEDLINE | ID: mdl-26931492

ABSTRACT

A hydroxy group directed keto α-C(sp3)-H benzoxylation of amides, including N,N-dialkylamides and cyclic amides, has been accomplished involving ortho-hydroxy substrates possessing either an aldehydic or a keto methyl (-COCH3) group with a Pd(II)/CuBr2 catalytic combination. The carboxy group obtained via the in situ oxidation of -CHO or -COCH3 groups of ortho-hydroxy substrates then undergoes a cross-dehydrogenative coupling (CDC) with amides to furnish an α-benzoxylation product with concurrent aromatic ring bromination.

19.
Org Lett ; 17(22): 5586-9, 2015 Nov 20.
Article in English | MEDLINE | ID: mdl-26528788

ABSTRACT

Intermolecular C-N bond formations via cross-dehydrogenative coupling (CDC) of aryl ethers and tetrazoles have been developed under a metal-free condition. In the presence of catalytic amount of tetrabutylammonium iodide (TBAI) and aqueous TBHP, aryl ethers coupled efficiently with tetrazoles to afford hemiaminal ethers. This strategy showed high level of regioselectivity for substrates possessing multiple sp(3) C-H bonds adjacent to the ethereal oxygen.

20.
Org Lett ; 17(22): 5678-81, 2015 Nov 20.
Article in English | MEDLINE | ID: mdl-26529054

ABSTRACT

Ruthenium(II) catalyzed oxidative C-H/O-H annulations have been demonstrated using two different directing arenes viz. 2-arylquinolinone and 2-arylbenzoxazinone with internal alkynes. Regiospecific annulations have been observed for both directing arenes via the assistance of weaker carbonyl oxygen in the presence of a stronger nitrogen-directing site. In this substrate-controlled convergent protocol the weaker directing group dictates the annulation path.

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