One-pot four-component synthesis of novel isothiourea-ethylene-tethered-piperazine derivatives.

An efficient metal-free four-component approach for the synthesis of piperazine derivatives tethered to an isothiourea group through an ethylene link was developed. 1,4-Diazabicyclo[2.2.2]octane (DABCO) salts, generated in situ through the reactions of DABCO with various alkyl bromides, reacted with phenylisothiocyanate (PITC) and amines in a one-pot manner to give the target products. Initially, through two parallel nucleophilic paths, DABCO and the secondary amine adds to the alkyl bromide and PITC, respectively. The process is followed by the combination of the two respective intermediates to produce the final products by forming a new C-S bond with the expense of a C-N bond cleavage. Consequently, various DABCO salts and secondary amines were tolerated well in this protocol to afford the isothiourea-ethylene-tethered-piperazine compounds in good to high yields.

Disruptive technologies as a solution for disaster risk management: A review.

Integrating disruptive technologies within smart cities improves the infrastructure needed to potentially deal with disasters. This paper provides a perspective review of disruptive technologies such as the Internet of Things (IoT), image processing, artificial intelligence (AI), big data and smartphone applications which are in use and have been proposed for future improvements in disaster management of urban regions. The key focus of this paper is exploring ways in which smart cities could be established to harness the potential of disruptive technologies and improve post-disaster management. The key questions explored are a) what are the gaps or barriers to the utilization of disruptive technologies in the area of disaster management and b) How can the existing methods of disaster management be improved through the application of disruptive technologies. To respond to these questions, a novel framework based on integrated approaches based on big data analytics and AI is proposed for developing disaster management solutions using disruptive technologies.

A Safety Warning Algorithm Based on Axis Aligned Bounding Box Method to Prevent Onsite Accidents of Mobile Construction Machineries.

Mobile construction machineries are accident-prone on a dynamic construction site, as the site environment is constantly changing and continuous safety monitoring by human beings is impossible. These accidents usually happen in the form of machinery overturning or collapsing into risk areas, including the foundation pit, slopes, or soft soil area. Therefore, preventing mobile construction machineries from entering risk areas is the key. However, currently, there is a lack of practical safety management techniques to achieve this. Utilizing a wireless sensor device to collect the location information of mobile construction machineries, this research develops a safety warning algorithm to prevent the machineries moving into risk area and reduces onsite overturning or collapsing accidents. A modified axis aligned bounding box method is proposed according to the movement patterns of mobile construction machineries, and the warning algorithm is developed based on the onsite safety management regulations. The algorithm is validated in a real case simulation when machinery enters the warning zone. The simulation results showed that the overall algorithm combining the location sensing technology and the modified bounding box method could detect risk and give warnings in a timely manner. This algorithm can be implemented for the safety monitoring of mobile construction machineries in daily onsite management.

Production scheduling of off-site prefabricated construction components considering sequence dependent due dates.

The growing environmental concerns, excessive utilization of natural resources, and high energy consumption have put a severe pressure on the construction industry to adopt new methods in response to these challenges. As a remedy, prefabricated construction methods are broadly utilized to enhance the productivity of the construction activities. However, challenges associated with on-time production of precast components have not adequately been addressed. Thus, this study proposes a new insight to the theory of scheduling dealing with sequence-dependent due dates, in which total weighted earliness and tardiness are minimized. To tackle uncertainties and complexities associated with the stochastic nature of production problems, three integrated simulation-optimization algorithms, which employ simulation methods inside a metaheuristic framework, are proposed. Three metaheuristic algorithms, including genetic algorithm (GA), differential evolution (DE), and imperialist competitive algorithm (ICA), are employed to minimize objective function. A series of computational tests are conducted to investigate the performance of these approaches. Results indicate that integrated DE-simulation approach can provide better results in comparison with other approaches.

Synthesis of New 3-Arylcoumarins Bearing N-Benzyl Triazole Moiety: Dual Lipoxygenase and Butyrylcholinesterase Inhibitors With Anti-Amyloid Aggregation and Neuroprotective Properties Against Alzheimer's Disease.

A novel series of coumarin derivatives linked to the N-benzyl triazole group were synthesized and evaluated against 15-lipoxygenase (15-LOX), and acetyl- and butyrylcholinesterase (AChE and BuChE) to find the most potent derivative against Alzheimer's disease (AD). Most of the compounds showed weak to moderate activity against ChEs. Among the most active BuChE and 15-LOX inhibitors, 8l and 8n exhibited an excellent neuroprotective effect, higher than the standard drug (quercetin) on the PC12 cell model injured by H2O2 and significantly reduced aggregation of amyloid Aß1-42, with potencies of 1.44 and 1.79 times higher than donepezil, respectively. Compound 8l also showed more activity than butylated hydroxytoluene (BHT) as the reference antioxidant agent in reducing the levels of H2O2 activated by amyloid ß in BV2 microglial cells. Kinetic and ligand-enzyme docking studies were also performed for better understanding of the mode of interaction between the best BuChE inhibitor and the enzyme. Considering the acceptable BuChE and 15-LOX inhibition activities as well as significant neuroprotection, and anti-amyloid aggregation activities, 8l and 8n could be considered as potential MTDLs for further modification and studies against AD.

Cu-metal organic frameworks (Cu-MOF) as an environment-friendly and economical catalyst for one pot synthesis of tacrine derivatives.

The present work describes the catalytic activity of Cu-MOF for the one-pot synthesis of tacrine derivatives via a four-component reaction of 2-hydroxynaphthalene-1,4-dione, aldehydes, malononitrile and cycloketones in the presence of AlCl3. The structure of the synthesized compound is confirmed by 1H NMR, 13C NMR, IR, and MASS. The catalyst prepared under pressure is characterized by powder X-ray diffraction and SEM. The noteworthy advantages of this procedure include its broad substrate scope, high yields up to 93%, atom economy, using readily available starting materials and a powerful recyclable nano catalyst. Additionally, there is no need to use column chromatography for purifying products so, it has the potential for large-scale applications in pharmaceutical industries. Another advantage of this method is the ability to recycle the catalyst up to 3 times and reuse it.

Development of biodegradable electrospun gelatin/aloe-vera/poly(ε­caprolactone) hybrid nanofibrous scaffold for application as skin substitutes.

Nowadays, aloe-vera (AV) is exploited extensively in nanofibrous structures for skin substitutes. However, the lack of electrospinnability and appropriate mechanical characteristics are the key limitations for this natural extract to be used in the form of nanofibrous mats. In this study, two commercially available biopolymers, gelatin (Gel) and poly(ε­caprolactone) (PCL), were chosen to improve these issues and double-nozzle electrospinning technique was used to fabricate hybrid scaffold from Gel/AV blend and PCL solutions. Response surface methodology was utilized to investigate the effect of electrospinning parameters (Gelatin concentration, Aloe-vera concentration and Gel/AV feed-rate) on the mechanical properties, morphology and hydrophilicity of nanofibers and the optimized scaffold was chosen for further studies. In order to verify the application of this scaffold in bioapplications, the chemical, thermal and biological features of scaffold were analyzed using FTIR, DSC, biodegradability, bactericidal, biocompatibility and drug-delivery. The results revealed that the presence of aloe-vera improved the antibacterial activity (>99% and 85.63% against Gram-positive and Gram-negative bacteria, respectively), and led to adequate in-vitro biodegradation. Furthermore, it was found that incorporation of aloe-vera increased the cell viability without any toxicity.

Synthesis and structure-activity relationship study of tacrine-based pyrano[2,3-c]pyrazoles targeting AChE/BuChE and 15-LOX.

A series of tacrine-based pyrazolo[4',3':5,6]pyrano[2,3-b]quinolines and related compounds were designed and synthesized for targeting AChE, BuChE and 15-LOX enzymes in the field of Alzheimer's disease therapy. Most of compounds showed potent activity against cholinesterases and mild potency toward 15-LOX enzyme. In particular, compounds 29, 32 and 40 displayed inhibition at nano-molar level against AChE and BuChE (IC50s = 0.005-0.08 µM), being more potent than reference drug tacrine. Moreover, compound 32 with IC50 value of 31 µM was the most potent compound against 15-LOX. The cytotoxicity assay on HepG2 cells revealed that compounds 29 and 32 showed no significant cytotoxic activity even at concentration of 50 µM. The cytotoxicity of compounds 29 and 32 was significantly less than that of tacrine at higher concentrations.

Ultrasound mediation for efficient synthesis of monoarylidene derivatives of homo- and heterocyclic ketones.

Ultrasonic irradiation was efficiently used for high yield synthesis of monoarylidene derivatives of cyclic systems directly from the reaction of ketone with various aldehydes under solvent-free conditions. Reactions took place rapidly in the presence of catalytic amounts of pyrrolidine, while no significant formation of the undesired bis by-products was observed. Moreover, the procedure was applicable to both homo- and heterocyclic ketones.

rac-3-[(3-Chloro-anilino)(4-chloro-phenyl)meth-yl]thian-4-one.

In the title compound, C(18)H(17)Cl(2)NOS, the thio-pyran-one ring adopts a chair conformation, with the substituent in the axial position. The dihedral angle between the two benzene rings is 89.43 (1)°. In the crystal, mol-ecules form inversion dimers through inter-molecular N-H⋯O hydrogen bonds [graph set R(2) (2)(8)].

rac-3-[(Anilino)(naphthalen-2-yl)-methyl]thian-4-one.

In the title compound, C(22)H(21)NOS, the thio-pyran-one ring adopts a chair-like conformation with the substituent in the axial position. The relative configuration of the racemic compound is 3R,7S according to the numbering scheme used in this publication. In the crystal packing, centrosymmetric dimers are built up via N-H⋯O hydrogen bonds, with graph set R(2) (2)(8).

(2E,6E)-2,6-Bis(4-methyl-benzyl-idene)cyclo-hex-3-en-1-one.

The title compound, C(22)H(20)O, shows an approximately planar cyclo-hexenone ring [maximum deviation = 0.069 (4) Å], with a disordered position of the C=C bond [ratio = 0.71 (2)/0.29 (2)]. The benzene rings of the 4-methyl-benzyl-idene units, attached in the 2- and 6-positions to the cyclo-hexenone ring, are rotated in the same direction by 28.6 (4) and 22.4 (4)°, with respect to the mean plane of the cyclo-hexenone ring [fraction 0.71 (2); maximum deviation = 0.06 (3) Å]. In the crystal, mol-ecules are packed in the manner of a distorted hexa-gonal rod packing with their long axes all aligned along [201]. A number of C-H⋯π inter-actions stablize the crystal structure.

(4Z,6Z)-4,6-Bis(4-meth-oxy-benzyl-idene)-2,2-dimethyl-1,3-dioxan-5-one.

The title compound, C(22)H(22)O(5), crystallizes with two independent mol-ecules in the asymmetric unit, both of which possess pseudo-C(s) symmetry. The central 1,3-dioxanone rings have envelope conformations, with the C atom bearing the two methyl groups at the flap. The benzene rings of the meth-oxy-benzyl-idene units, attached in the 4- and 6-positions on the central 1,3-dioxanone rings, are tilted in the same direction with dihedral angles varying between 8.2 (1) and 18.1 (1)°. The crystal packing is influenced by π-stacking inter-actions of the parallel displaced type [centroid-centroid distance of 3.723 (1) Šfor mol-ecule 1 and 3.884 (1) Šfor mol-ecule 2, with ring slippages of 1.432 and 1.613 Å, respectively] and the T-shaped type, with the long mol-ecular axes all aligned along [010].

Switching the reactivity of dihydrothiopyran-4-one with aldehydes by aqueous organocatalysis: Baylis-Hillman, aldol, or aldol condensation reactions.

An aqueous medium containing catalytic amounts of a tertiary amine was employed to direct the chemoselectivity of the reaction of aldehydes with 1a. With DBU, 2 was formed at room temperature as a rare exemplary of Baylis-Hillman reactions in heterocyclic enones. DABCO alternated the pathway toward an aldol reaction to form syn/anti mixtures of 3 with the syn isomers being the major products. With Et(3)N, aldol condensation dominated.

Diels-alder reactions of styrylcyclohexenones: an efficient procedure for the synthesis of substituted dehydrodecaline derivatives.

The Diels-Alder reaction of styrylcyclohex-2-enone derivatives 1 with N-phenylmaleimide was shown to be an efficient pathway for the synthesis of substituted dehydrodecaline derivatives. At elevated temperatures, mixtures of endo/exo adducts were formed, while in the presence of TiCl4 exclusive formation of the endo stereoisomer was observed. Spectroscopic analysis and X-ray crystallography confirmed the formation of the endo adducts.

Convenient ultrasound mediated synthesis of substituted pyrazolones under solvent-free conditions.

Smooth condensation of hydrazine derivatives with various beta-keto esters was performed under solvent-free conditions by using ultrasound irradiation to facilitate the formation of pyrazolone derivatives in good to excellent amounts within very short time periods.

Ultrasound promoted aminolysis of epoxides in aqueous media: a rapid procedure with no pH adjustment for additive-free synthesis of beta-aminoalcohols.

An efficient and environmentally friendly procedure promoted by ultrasound irradiation is developed for stereoselective ring opening of various epoxides with aromatic and aliphatic amines under aqueous conditions in the presence of no catalyst or additive. Chemoselectivity of the protocol is shown by competition of piperidine and aniline to react with different epoxides resulting in exclusive formation of the respective products of piperidine.

Lithium bromide as a flexible, mild, and recyclable reagent for solvent-free Cannizzaro, Tishchenko, and Meerwein-Ponndorf-Verley reactions.

A room temperature convenient disproportionation or reduction of aldehydes prompted by lithium bromide and triethylamine is described in a solvent-free environment. Distribution of the products to selectively direct the process toward Cannizzaro or Tishchenko reactions is controlled by the type of workup selection. The presence of hydrogen donor alcohols in the mixture completely diverts the process toward the Meerwein-Ponndorf-Verley reaction.

Chiral separation of three agrochemical toxins enantiomers by high-performance liquid chromatography on a vancomycin crystalline degradation products-chiral stationary phase.

This work aims to evaluate for the enantiomeric separations of three agrochemical toxins: haloxyfop-methyl, fenoxaprop-p-ethyl and indoxacarb on crystalline degradation products-chiral stationary phase (CDP-CSP) of high-performance liquid chromatography (HPLC) under normal and polar organic phases. In the normal phase, the mobile phase was n-hexane with alcohols including methanol and isopropanol as polar modifiers. In the polar organic phase mode, the mobile phase was methanol with different percentages of triethylammunium acetate. The influence of flow rate (0.3-0.9 mL/min), analyte concentration and silica gel particle sizes (10, 15 and 30 microm) was investigated. This new chiral stationary phase showed excellent stereoselectivity for the two enantiomers of haloxyfop-methyl and fenoxaprop-p-ethyl and chiral recognition for indoxacarb under normal-phase mode. However, under polar organic phase, only indoxacarb was separated (alpha < 1.5). The chromatographic results were compared with commercial chiral columns.

Ultrasound promoted protection of alcohols: an efficient solvent-free pathway for the preparation of silyl ethers in the presence of no additive.

Various types of alcohols and phenols were rapidly protected by hexamethyldisilazane in good to excellent yields at room temperature using high-intensity ultrasound irradiation in the presence of no solvent or any additive. Good to excellent chemoselectivity was observed for competitive protection of hydroxyl groups in favor of sterically less hindered alcohols. Exclusive protection of phenols in the presence of aromatic amines was also demonstrated successfully.