The key step for the synthesis of 7-hydroxy 2,3-diarylsubstituted benzothiophenes 5a-f , by starting from substituted 2-aryl-2-((2-methoxy phenyl)thio)acetophenones 3a-f as an intermediate, consists of a Friedel-Crafts cyclization followed by demethylation by Lewis acids like BF 3 OEt 2 and AlCl 3 in DCM. 相似文献
A straightforward and general approach for the stereoselective synthesis of fused pyrrolo[1,2‐a] indoles frameworks from>intramolecular 1,3‐dipolar cycloaddition using N‐alkylated Baylis–Hillman derivatives is presented. It was found that the cycloaddition proceeded efficiently under microwave irradiation in solvent‐free condition to afford highly stereoselective cycloadducts in good yield. 相似文献
A simple and convenient procedure for the synthesis of nitriles by dehydration of aldoximes using a PCC (pyridiniumchlorochromate) has been developed. A variety of aromatic, heteroaromatic, and aliphatic aldoximes are converted.
Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the full spectral details. 相似文献
Highly regio- and stereoselective synthesis of glucosylspiro-oxindole/acenaphthenone derivatives was accomplished through 1,3-dipolar cycloaddition (1,3-DC) reaction. The glucosyl α,β-unsaturated-7,3-lactone (a sugar lactone) derived from d-glucose was used as a chiral dipolarophile in 1,3-DC reaction for the first time. The azomethine ylides generated from sarcosine/l-proline/thiazolidine-4-carboxylic acid/piperidine-2-carboxylic acid with isatin and acenaphthoquinone were trapped by the sugar lactone to give a series of glucosylspiro-pyrrolidine derivatives in good yields. 相似文献
Esaxerenone is a new nonsteroidal mineralocorticoid receptor antagonist utilized to treat high blood pressure. Chemically, esaxerenone is a pyrrole derivative consisting of hindered rotation, which results in stereoisomers named atropisomers. Currently, no methods exist for the separation and quantification of these atropisomers. A new and accurate chiral liquid chromatographic technique was developed and validated to estimate the enantiomeric purity of esaxerenone. Polar organic chiral separation was carried out on an immobilized amylose-based chiral stationary phase (Chiralpak IG) with methanol:acetonitrile:diethylamine (9:1:0.1, v/v/v) mixture as a mobile phase. The total runtime was 15 min, and the resolution (Rs) between the atropisomers was more than 3.0. The detection and quantification thresholds for the R-atropisomer were found to be 0.03 and 0.1 µg mL?1, respectively, for a test concentration of esaxerenone (1000 µg mL?1). Over the range from the limit of quantification to 0.3 percent, the method's linearity for the R-atropisomer was excellent (R2?>?0.999). The R-atropisomer recovery varied from 95 to 102%, confirming the method’s good accuracy. For a 48-h research period, the chemical was shown to be stable.
One-pot three-component synthesis of twelve different chromeno[2,3-b]indole derivatives were achieved by the condensation of β-naphthol, oxindole and various substituted aldehydes. Two more chromeno[2,3-b]indole derivatives were also synthesized through one-pot two-component condensation of salicylaldehyde with oxindole/chlorooxindole. Both the condensations were achieved by using Keggin-type heteropoly-11-molybdo-1-vanadophosphoric acid, H4[PVMo11O40] supported on montmorillonite K-10 clay for about 10% as catalyst under environmentally benign solvent-free reaction condition. Shorter reaction time, excellent yield of product, sustainability of catalytic material and simple workup procedure under green experimental conditions are the advantages of this protocol.
A convenient approach to the synthesis of 2-amino-4,6-diphenylnicotinonitriles via four-component reaction of aromatic aldehydes, acetophenone derivatives, malononitrile and ammonium acetate is described. The reactions were done in water as solvent using cellulose sulfuric acid as catalyst. This simple protocol offer advantages such as shorter reaction times, simple work-up procedure, excellent yields and catalyst recovery. 相似文献
As machine learning algorithms grow in popularity and diversify to many industries, ethical and legal concerns regarding their fairness have become increasingly relevant. We explore the problem of algorithmic fairness, taking an information–theoretic view. The maximal correlation framework is introduced for expressing fairness constraints and is shown to be capable of being used to derive regularizers that enforce independence and separation-based fairness criteria, which admit optimization algorithms for both discrete and continuous variables that are more computationally efficient than existing algorithms. We show that these algorithms provide smooth performance–fairness tradeoff curves and perform competitively with state-of-the-art methods on both discrete datasets (COMPAS, Adult) and continuous datasets (Communities and Crimes). 相似文献
Temperature dependent Mössbauer measurements are done on the samples of La1–xCaxMn1–y57FeyO3 with x=0 and 0.25, and y=0.01. With decreasing temperature, the specimen with x=0.25 shows a paramagnetic to ferromagnetic transition around 175 K. In the specimen x=0.0, the temperature dependence of both the center shift () and the recoilless fraction (f) can be fitted very well with the Debye theory with a
D=320±50 K. But for the specimens with x=0.25, f and show distinct deviations from the Debye behavior in the temperature range in which the resistivity shows a sharp decrease. Dips observed in both the f and around the transition temperature suggest that the Jahn–Teller distortion observed in these systems is dynamic in nature. 相似文献
We have shown in this paper that the relative acceleration between neighbouring particles in the field of an isolated mass is finite at the apparent singular surfacer = 2m. The analysis is made both in Schwarzschild and Eddington-Finkelstein coordinate systems by using the equation of geodesic deviation. 相似文献