Reactions in water as a safe and cheap solvent is a major goal of green chemistry. Actual synthesis of pyrido-dipyrimidine scaffold, named DNA-base hybrids, involves catalysis in hazardous solvents. ...Here we synthesised pyrido-dipyrimidines by one-pot heterocyclization of thiobarbituric acid, vanillic aldehydes and amines in water. Enamine and vanillidene are key intermediates of the Biginelli-like reaction mechanism. Our synthetic method displays several benefits such as the use of a green medium and various substrates, and yields up to 99%.
This article describes a teaching strategy that synergizes computing and management, aimed at the running of complex projects in industry and academia, in the areas of civil engineering, physics, ...geosciences, and a number of other related fields. The course derived from this strategy includes four parts: (a) Computing with a selected set of modern paradigms—the stress is on Control Flow and Data Flow computing paradigms, but paradigms conditionally referred to as Energy Flow and Diffusion Flow are also covered; (b) Project management that is holistic—the stress is on the wide plethora of issues spanning from the preparation of project proposals, all the way to incorporation activities to follow after the completion of a successful project; (c) Examples from past research and development experiences—the stress is on experiences of leading experts from academia and industry; (d) Student projects that stimulate creativity—the stress is on methods that educators could use to induce and accelerate the creativity of students in general. Finally, the article ends with selected pearls of wisdom that could be treated as suggestions for further elaboration.
This article presents a taxonomy and represents a repository of open problems in computing for numerically and logically intensive problems in a number of disciplines that have to synergize for the ...best performance of simulation-based feasibility studies on nature-oriented engineering in general and civil engineering in particular. Topics include but are not limited to: Nature-based construction, genomics supporting nature-based construction, earthquake engineering, and other types of geophysical disaster prevention activities, as well as the studies of processes and materials of interest for the above. In all these fields, problems are discussed that generate huge amounts of Big Data and are characterized with mathematically highly complex Iterative Algorithms. In the domain of applications, it has been stressed that problems could be made less computationally demanding if the number of computing iterations is made smaller (with the help of Artificial Intelligence or Conditional Algorithms), or if each computing iteration is made shorter in time (with the help of Data Filtration and Data Quantization). In the domain of computing, it has been stressed that computing could be made more powerful if the implementation technology is changed (Si, GaAs, etc.…), or if the computing paradigm is changed (Control Flow, Data Flow, etc.…).
The selective synthesis of 5,6-dihydropyrimidin-4(3H)-one scaffold (precursor of dihydrouracil) was a very difficult synthetic challenge that, so far, has not been achieved. For the first time, in ...this paper, green, selective and high-yields approach to 40 novel 5,6-dihydropyrimidin-4(3H)-ones (DHPMs) by one-pot reaction of aldehydes, Meldrum’s acid and isothioureas under solvent-free conditions, in the presence of water, since an additive is presented. In the majority of cases, introduced methodology gave an unprecedented tautomer-selective fashion toward targeted compounds with excellent tautomeric purity (>99.9%), which reached 100% in few cases. The molecular structure of the five compounds has been determined by X-ray crystallography. In each one of them, very short length for the corresponding N2–C1 bond was noticed, making them especially interesting from a structural standpoint. This experimental fact can imply a highly localized electron π density in this part of each heterocyclic ring. The obtained experimental results, which are determined from NMR and ESI-MS study, indicate that this Biginelli-type reaction smoothly proceeds in a one-pot mode, pointing to the three-step tandem process, proceeding via the Knoevenagel, aza-Michael, and retro-Diels–Alder reactions. The presented strategy also had the following advantages: reduction amount of waste, excellent values of green chemistry metrics (cEF, EcoScale and GCIS), and it is the first eco-friendly strategy toward the DHPMs scaffold.
In this study, we consider a production lot-sizing and scheduling problem found in the fruit juice production industry from an enhanced inventory management perspective. The problem can be classified ...as a P2SMM (two-stage multi-machine lot-scheduling) problem. We extended the classical P2SMM problem by incorporating an additional inventory management aspect of finished products to reflect a possible real-life case problem, specifically regarding the shelf-life concept and limited warehouse capacity, with a possibility of outsourcing the warehousing demand to a third-party logistics company. We developed the mixed integer linear programming (MILP) model to fully represent the considered problem (due to the NP-hard nature of the problem, only small-scale instances could be solved to optimality), and the hybrid variable neighborhood search with linear programming (VNS/LP) model to solve both small and real-life large-scale problem instances. The goal of the developed models is to minimize total costs that consist of the cost of backordering, the cost of planned minimum and maximum stock level violation, the cost of warehouse capacity overflow, the costs of production setup time and unused available production time. The main idea of the VNS/LP model is to solve the scheduling segment of P2SMM (the production sequence) via a VNS heuristic, and the lot-sizing segment of P2SMM via the linear programming (LP) model. Based on the results from five variants of the problem setup, a potential decision maker can have an overview of the impact of different important input parameters (production time costs, warehouse capacity and costs, inventory related costs and production demand) on the total cost of a production process and improve its efficiency in changing conditions.
A small library of novel 2-oxo-1,2,3,4-tetrahydropyrimidines was synthesized via a one-pot multicomponent Biginelli reaction. Copper complex
(
PhNH
3
)
2
CuCl
4
,
which was used for the first time as ...a homogeneous and heterogeneous catalyst, makes this a facile and efficient reaction at room temperature. All the obtained products fall out of the solution in pure form and are easily isolated via filtration in good-to-excellent yields. The molecular structure of one of the products, ethyl 6-methyl-2-oxo-4-(4
′
-isopropoxy-3
′
-methoxyphenyl) - 1,2,3,4 - tetrahydropyrimidine-5- carboxylate, has been determined by X-ray crystallography. All non-hydrogen atoms in the heterocyclic, six-membered ring are determined to be approximately coplanar.
A series of novel O-alkyl vanillidene derivatives containing Meldrum's acid scaffold under solvent-free conditions were synthesized. The antimicrobial activity was estimated by determination of the ...minimal inhibitory concentration (MIC) using the broth microdilution. The most active compounds were 5-(4'-hydroxy-2'-iodo-3'-methoxybenzylidenyl)- 2,2-dimethyl-1,3-dioxane-4,6-dione (3a), 5-(4'-acetoxy-3'-methoxybenzylidenyl)-2,2-dimethyl-1, 3-dioxane-4,6-dione (3f), and 5-(4'-bromopropoxy-3'-methoxybenzylidenyl)-2,2-dimeth yl-1,3-dioxane-4,6-dione (3h) with the MIC values ranging from 0.039 to 10 mg mL super(-1). Antioxidant activity was evaluated by DPPH free radical scavenging activity. 3h showed the largest scavenging activity with an IC sub(50) value of 55.61 mu g mL super(-1) (0.14 mmol L super(-1)). The interaction of 3a and 3h with DNA and bovine serum albumin (BSA) were investigated by the fluorescence spectroscopic method. The results achieved in competitive experiments with ethidium bromide (EB) indicated that 3a and 3h have an affinity to displace EB from the EB-DNA complex through intercalation. Fluorescence spectroscopy data show that the fluorescence quenching of BSA is a result of the formation of the 3a- and 3h-BSA complex species, and indicate that 3a-BSA is more stable, suggesting that 3h-BSA is less suitable for drug-cell interactions.
Vanillin O -alkylated derivatives and acetylferrocene reacted under Claisen–Schmidt conditions yielding the corresponding ferrocene containing chalcones in good-to-high yields. Under similar ...conditions, O -alkylated derivatives of acetovanillone were reacted with ferrocenylcarbaldehyde. Two series of novel N -acetyl and N -formyl pyrazoline derivatives were prepared by cyclocondensation of previously described chalcones (containing ferrocene framework and vanillic fragment) with hydrazine hydrate in acidic solvent (formic acid or acetic acid). All synthesized compounds were fully characterized by spectral and physical data and were tested for their biological activity. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration using the broth microdilution method. The activity of the synthesized compounds was compared with standard antibiotics. The most active antibacterial compounds were 1-5-(3,4-dimethoxyphenyl)-3-ferrocenyl-4,5-dihydro-1 H -pyrazol-1-ylethanone ( 4a ) and 1-5-(4-benzyloxy-3-methoxyphenyl)-3-ferrocenyl-4,5-dihydro-1 H -pyrazol-1-ylethanone ( 4f ); the best antifungal activity was shown by compounds of type 4 . The interaction of 4a , 4f , 5a and 5e with DNA and bovine serum albumin (BSA) were investigated by fluorescence spectroscopic method. The results achieved in competitive experiments with ethidium bromide (EB) indicated that 4a and 5e have larger affinity to displace EB from the EB–DNA complex than 4f and 5a , probably through intercalation. Fluorescence spectroscopy data show that the fluorescence quenching of BSA is a result of the formation of the 4a , 4f , 5a and 5e –BSA complex species. Measured values of K a showed that compounds which contain the acetovanillone-formyl core ( 5a and 5e ) formed more stable complexes with BSA than compounds with the vanillin-acetyl core ( 4a and 4f ), suggesting that 4a – and 4f –BSA are less suitable for drug–cell interactions.
Gravel distribution by an inland waterway transport is characterized with very intensive material flows and very low profit margins. Therefore, gravel distribution companies are in constant efforts ...on improving system efficiency by increasing productivity of existing facilities. Barges' unloading activity is executed at the end of inland waterway transport process and has a large influence on productivity of whole system, since minimization of time that barges spend waiting for services maximize time they transport gravel, i.e. their productive time. In this paper, the authors transfer this optimization problem in a well known class of multiple traveling repairman problem with time windows. Due to time consuming solution process in case of real size problem instances, beside optimal mathematical formulation of the problem, they present a solution approach based on Variable Neighborhood Search metaheuristic algorithm.
Rapid urbanization, intensified industrialization, rise of income, and a more
sophisticated form of consumerism are leading to an increase in the amount
and toxicity of waste all over the world. ...Whether reused, recycled,
incinerated or put into landfill sites, the management of household and
industrial waste yield financial and environmental costs. This paper presents
a modeling approach that can be used for designing one part of recycling
logistics network through defining optimal locations of collection points,
and possible optimal scheduling of vehicles for collecting recyclables.
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