A Structural and Calorimetric Study on the Interaction Between Jack Bean Urease and Cyanide Ion

The cyanide ion was studied as an effecter of Jack bean urease at 300 K in 30 mmol⋅L⁻¹ Tris buffer, pH=7. The inhibition was investigated by isothermal titration calorimetry (ITC). The extended solvation model was used for CN⁻+JBU interaction over the whole range of CN⁻ concentrations. The binding parameters recovered from the solvation model were attributed to the interaction with cyanide ion. It was found that cyanide ion acted as a noncooperative inhibitor of urease, and there is a set of 12 identical and independent binding sites for CN⁻ ions. The dissociation equilibrium constant is 749.99 μmol⋅L⁻¹. The molar enthalpy of binding is ΔH=−13.60 kJ⋅mol⁻¹.     

A Three‐Component One‐Pot Synthesis of Functionalized 5,5‐Dicyanocyclopenta‐1,3‐dienes from Arylidene­malononitriles,Activated Acetylenes,and KCN or KSCN

The reaction of dialkyl acetylenedicarboxylates with arylidenemalononitriles in the presence of KSCN in MeCN led to a mixture of dialkyl (3E)‐4‐aryl‐3‐(arylideneamino)‐5,5‐dicyanocyclopenta‐1,3‐diene‐1,2‐dicarboxylates and dialkyl 4‐aryl‐5‐cyanothiophene‐2,3‐dicarboxylates. When these reactions were performed in the presence of KCN, only the functionalized 5,5‐dicyanocyclopenta‐1,3‐dienes were obtained.     

A Novel One‐Pot Synthesis of Substituted Quinolines

A synthesis of quinoline derivatives is described via reaction between ethyl bromopyruvate (=ethyl 3‐bromo‐2‐oxopropanoate), acetylenedicarboxylate, and isatin (=1H‐indole‐2,3‐dione) in the presence of NaH as a base. Also, these reactions were performed without ethyl bromopyruvate. The reaction in the presence of ethyl bromopyruvate provides regioselectively a quinoline with the ethyl ester group in 4‐position. In the absence of ethyl bromopyruvate, the reaction leads to functionalized quinolines with the same ester groups in 2‐, 3‐, and 4‐positions.     

Potassium Thiocyanate‐Promoted One‐Pot Synthesis of (1,3‐Diaryl‐2,5‐dioxoimidazolidin‐4‐ylidene)acetates from Aryl Isocyanates and Alkyl Propiolates. Short Communication

The reaction of aryl isocyanates and alkyl propiolates (=alkyl prop‐2‐ynoates) in the presence of potassium thiocyanate (KSCN) led to geometric isomers of alkyl 2‐(1,3‐diaryl‐2,5‐dioxoimidazolidin‐4‐ylidene)acetates in moderate‐to‐good yields.     

Synthesis of new 1,5-diaryl-3-(arylamino)-1H-pyrrol-2(5H)-ones under catalyst-free and solvent-free conditions

Several new 1,5-diaryl-3-(arylamino)-1H-pyrrol-2(5H)-ones were synthesized via the three-component condensation reaction of aldehydes, aromatic amines, and ethyl pyruvate under catalyst-free and solvent-free conditions. Also, 5-(4-hydroxyl-3-nitrophenyl)-1-(4-methoxy-phenyl)-3-(4-methoxyphenylamino)-1,5-dihydro-pyrrol-2-one was synthesized using oxime instead of aldehyde. The eco-friendly, simple procedure, green procedure, catalyst-free and solvent-free conditions, short reaction times, and high yields of the products are the advantages of this method.     

Novel Synthesis of Oxygenated Coumarins from Substituted Phenols Mediated by Vinyl Triphenylphosphonium Salt Under Microwave Irradiation

Protonation of the highly reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate(DMAD) by substituted phenols lead to vinyl triphenylphosphonium salts, which undergo aromatic electrophilic substitution reaction with a phenolate conjugate base to produce 4-carboxymethyl coumarins in fairly highly yields.     

Solvent-Free,Microwave-Assisted,One-Pot Synthesis of 2-Acetyl-N,3-diaryl-4-nitro-butanamides

A combination of benzyltriethylammonium borohydride and chlorotrimethylsilane (1:1) in dichloromethane (0–25°C) has been found to be a convenient reagent system for the selective reduction of carboxylic acids to alcohols.     

Formal Analysis of Optical Systems

Optical systems are becoming increasingly important by resolving many bottlenecks in today’s communication, electronics, and biomedical systems. However, given the continuous nature of optics, the inability to efficiently analyze optical system models using traditional paper-and-pencil and computer simulation approaches sets limits especially in safety-critical applications. In order to overcome these limitations, we propose to employ higher-order-logic theorem proving as a complement to computational and numerical approaches to improve optical model analysis in a comprehensive framework. The proposed framework allows formal analysis of optical systems at four abstraction levels, i.e., ray, wave, electromagnetic, and quantum.