COMMUNICATION | doi:10.20944/preprints201909.0294.v1
Subject: Chemistry, Organic Chemistry Keywords: multicomponent reaction; α-halohydrazones; staudinger reaction; aza-wittig; 1h-imidazole-2(3h)-thione; 2h-imidazo[2,1-b][1,3,4]thiadiazine
Online: 26 September 2019 (09:46:54 CEST)
A Multicomponent Reaction (MCR) strategy, alternative to the known cycloaddition reaction, towards variously substituted 1-amino-1H-imidazole-2(3H)-thione derivatives has been successfully developed. The novel approach involves α-halohydrazones whose azidation process followed by tandem Staudinger/aza-Wittig reaction with CS2 in a sequential MCR regioselectively leads to the target compounds avoiding the formation of the regioisomer iminothiazoline heterocycle. The approach can be applied to a range of differently substituted α-halohydrazones bearing also electron-withdrawing groups confirming the wide scope and the substituent tolerance of the process for the synthesis of the target compounds. Interestingly, the concurrent presence of reactive functionalities in the scaffolds so obtained, ensures postmodifications in view of N-bridgedheaded heterobicyclic structures.
ARTICLE | doi:10.20944/preprints202111.0571.v1
Subject: Chemistry, Other Keywords: Aminoglutethimide; Multicomponent solid form; Eutectic Mixure; Solubility
Online: 30 November 2021 (13:22:31 CET)
Here, we report the synthesis and experimental characterization of three drug-drug eutectic mixtures of drug aminoglutethimide (AMG) with caffeine (CAF), nicotinamide (NIC) and ethenzamide (ZMD). The eutectic mixtures (AMG-CAF, AMG-NIC and AMG-ZMD) demonstrate significant melting point depressions ranging from 99.2 to 127.2 °C compared to the melting point of the drug AMG (151°C) and also show significantly higher aqueous solubilities than that of the AMG. The results presented include the determination of the binary melt phase diagrams and accompanying analytical characterization via X-ray powder diffraction, FT-IR spectroscopy and Scanning electron microscopy.
Subject: Physical Sciences, Mathematical Physics Keywords: discrete fragmentation; multicomponent; partition function; multiplicity of distribution
Online: 8 September 2020 (11:13:13 CEST)
We formulate the statistics of the discrete multicomponent fragmentation event using a methodology borrowed from statistical mechanics. We generate the ensemble of all feasible distributions that can be formed when a single integer multicomponent mass is broken into fixed number of fragments and calculate the combinatorial multiplicity of all distributions in the set. We define random fragmentation by the condition that the probability of distribution be proportional to its multiplicity and obtain the partition function and the mean distribution in closed form. We then introduce a functional that biases the probability of distribution to produce in a systematic manner fragment distributions that deviate to any arbitrary degree from the random case. We corroborate the results of the theory by Monte Carlo simulation and demonstrate examples in which components in sieve cuts of the fragment distribution undergo preferential mixing or segregation relative to the parent particle.
ARTICLE | doi:10.20944/preprints201811.0015.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: metabolic syndrome; multicomponent functional foods; antioxidant bioactive ingredients; polyphenols
Online: 2 November 2018 (05:06:26 CET)
The ANTIATERO-ALIM study was a randomized, parallel design nutritional trial testing functional food (FF) diets against the usual diet recommended in the metabolic syndrome. Functional meals included balsamic vinegar from apples and honey and grape juice enriched with polyphenols from seeds of red grapes. 300 patients with metabolic syndrome were randomized into 4 groups: gr.1: FF + Ω-3 supplements, gr.2: FF, gr.3: Ω-3 supplements, gr.4: control. IRHOMA insulin resistance, plasma lipids and oxidative stress were assessed at inclusion and at 6 months. After 6 months there was a very significant decrease of oxidative stress in group 3, followed by a significant decrease in groups 1 and 2.
REVIEW | doi:10.20944/preprints202204.0151.v1
Subject: Chemistry, Medicinal Chemistry Keywords: Isocyanide-based multicomponent reactions; Antimicrobial Discovery; Antibiotic Resistance; Public Health
Online: 18 April 2022 (03:38:08 CEST)
Multicomponent reactions (MCR) have been used to synthesis a wide range of analogs from several classes of heterocyclic compounds, with multifaceted medicinal uses. The synthesis of highly functionalized molecules in a single pot is a unique property of MCR, allowing researchers to quickly assemble libraries of compounds of biological interest and uncover novel leads as possible therapeutic agents. Isocyanide-based multicomponent reactions have proven to be extremely effective at swiftly specifying members of compound libraries, particularly in discovery of drug . The understanding of structure-activity correlations that drive the development of new goods and technology, requires structural variety in these libraries. In current world, antibiotic resistance is a major ongoing problem which is developing a problematic scenario in public health. The implementation of isocyanide based multicomponent reactions uphold a significant potential in this regard. By utilizing such reactions, new antimicrobial compounds can be discovered and fight against such concerns. This study discusses recent developments in antimicrobial medication discovery using isocyanide-based multicomponent reactions (IMCRs). Furthermore, the article emphasizes the potential of IMCRs in the near future.
ARTICLE | doi:10.20944/preprints202105.0722.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Dementia; multicomponent training; long-term care home; social ethical approach
Online: 31 May 2021 (09:45:37 CEST)
Multicomponent training is recommended for people with dementia living in long-term care homes. Nevertheless, evidence is limited and people with severe dementia are often excluded from trials. Hence, the aim of this study was to investigate (1) the feasibility and (2) the requirements regarding a multicomponent training for people with moderate to severe dementia. The study was conducted as an uncontrolled single arm pilot study with a mixed methods approach. 15 nursing home residents with a mean age of 82 years (range: 75-90 years; female: 64%) with moderate to severe dementia received 16 weeks of multicomponent training. Feasibility and requirements of the training were assessed by a standardized observation protocol. Eleven participants regularly attended the intervention. The highest active participation was observed during gait exercises (64%), the lowest during strength exercises (33%). It was supportive if exercises were task-specific or related to everyday life. This study confirms that a multicomponent training for the target group is (1) feasible and well accepted. To enhance active participation (2) individual instructions and the implementation of exercises related to everyday life is required. The effectiveness of the adapted training should be tested in future randomized controlled trials.
Subject: Chemistry, Analytical Chemistry Keywords: Carbon dioxide chemistry; Copper catalysis; Synthetic methods; Multicomponent reaction; Cyclization
Online: 18 January 2021 (12:40:17 CET)
With the aim of profitable conversion of carbon dioxide (CO2) in an efficient, economical and sustainable manner, we developed a CuBr/ionic liquid (1-butyl-3-methylimidazolium acetate) catalytic system which could efficiently catalyze the three-component reactions of propargylic alcohols, 2-aminoethanols, and CO2 to produce 2-oxazolidinones and α-hydroxy ketones. Remarkably, this catalytic system employed lower metal loading (0.0125-0.5 mol%) but exhibited the highest turnover number (2960) ever reported, demonstrating its excellent activity and sustainability. Moreover, our catalytic system could efficiently work under 1 atm of CO2 pressure and recycle among the metal-catalyzed systems.
REVIEW | doi:10.20944/preprints202206.0415.v1
Subject: Chemistry, Organic Chemistry Keywords: 3,4-DHPo; 1,4-DHPs; multicomponent reaction; non-conventional synthesis; synthetic precursors
Online: 30 June 2022 (06:11:45 CEST)
3,4-Dihydro-2(1H)-pyridones (3,4-DHPo) and their derivatives are privileged structures present in natural products, which has been increased its relevance due to its biological activity in front of a broad range of targets, but especially for its importance as synthetic precursors of a variety of compounds with marked biological activity. Taking into account the large number of contributions published over the years regarding this kind of heterocycle, here we presented a current view of 3,4-dihydro-2(1H)-pyridones (3,4-DHPo), which include general aspects such as those related to nomenclature, synthesis, and biological activity; but also highlighting the importance of DHPo as building blocks of other relevance structures.
ARTICLE | doi:10.20944/preprints201804.0208.v1
Subject: Earth Sciences, Geophysics Keywords: fracture density; double-layer model; unconventional reservoirs; multicomponent seismic; shear-wave splitting
Online: 16 April 2018 (11:33:54 CEST)
Fracture density, a critical parameter of unconventional reservoirs, can be used to evaluate potential of unconventional reservoirs and location of production wells. Many technologies, such as amplitude variation with offset and azimuth (AVOA) technology, vertical seismic profiling (VSP) technology, and multicomponent seismic technology, are generally used to predict fracture of reservoirs. they can qualitatively predict fracture by analyzing seismic attributes, including seismic wave amplitudes, seismic wave velocities, which are sensitive to fracture. However, it is important to quantitatively describe fracture of reservoirs. In this study, based on a double-layer model, the relationships between fracture density and the double-layer model’s physical parameters, such as velocity of fast shear-wave, velocity of slow shear-wave, and density, were established, and then a powerful quantitative prediction method for fracture density was proposed dramatically. Afterwards, the Hudson model for crack was used to test the applicability of the method. The result shown that the quantitative prediction method for fracture density can be applied suitable to the Hudson model for crack. Finally, the result of validation models indicated that the method can predict fracture density effective, in which absolute relative deviation (ARD) were less than 5% and root-mean-square error (RMSE) was 4.88×10-3.
REVIEW | doi:10.20944/preprints201701.0122.v1
Subject: Chemistry, Organic Chemistry Keywords: multicomponent reaction; MCR; post condensation modification PCM; post condensation cyclisation PCC; MFCR; multifunction catalysis; variability; diversity; complexity; efficiency of synthesis
Online: 26 January 2017 (10:04:55 CET)
Synergistic effects between reactions, reagents and catalysts can lead to minor heats of reaction and occur as an inherent result of multi-component reactions (MCRs) and their extensions. They enable syntheses to be performed at a low energy level and the number of synthesis steps to be drastically reduced in comparison with ‘classical’ two-component reactions. The very high potential for variability, diversity and complexity of MCRs additionally generates an extremely diverse range of products, thus bringing us closer to the aim of being able to produce tailor-made and extremely low-priced materials, drugs and libraries.