Short Reaction Research Articles

Use of convertible isocyanides for the synthesis of benazepril hydrochloride

Herein, we have described a novel and concise synthesis of the potent angiotensin-converting enzyme (ACE) inhibitor, benazepril hydrochloride (7) in trifluoroethanol via an Ugi three-component reaction in shorter reaction times. The key step is the trifluoroacetic acid-mediated hydrolysis of secondary amides (4a and 4b) followed by esterification as a domino process to form corresponding ethyl ester (6). Mainly two universal convertible isocyanides (1a and 1b) were used for the synthesis of benazepril hydrochloride. Synopsis: An efficient synthesis of benazepril hydrochloride using Ugi three-component reaction.

Crystalline salicylic acid as an efficient catalyst for ultrafast Paal–Knorr pyrrole synthesis under microwave induction

In this study, the viability of a wide range of crystalline aromatic and aliphatic carboxylic acids as organocatalysts has been investigated for solvent-free Paal–Knorr pyrrole synthesis under microwave activation. Among these potential catalysts, crystalline salicylic acid proved to be a remarkable catalyst because its efficiency remained high even under low microwave power irradiation or a shorter reaction time for the model reaction. The outstanding catalytic activity of salicylic acid allowed the Paal–Knorr cyclocondensation with a turnover frequency up to 1472 h−1 which is unique in the context of a metal-free homogeneous catalysis. The attractive feature of this organocatalyst is its assistance in ultrafast pyrrole synthesis with no risk of metal contamination. Synopsis: A green and expeditious protocol for the synthesis of 2,5-dimethylpyrroles via combination of salicylic acid as catalyst (in its solid state) and microwaves has been introduced.

The development of an effective synthetic route of rilpivirine

BackgroundRilpivirine (RPV) was approved by the U.S. FDA (Food and Drug Administration) in 2011 to treat individuals infected with human immunodeficiency virus 1 (HIV-1). Significantly, rilpivirine is three fold more potent than etravirine. Once-daily, it is used with a low oral dose (25 mg/tablet), decreasing the drug administration and bringing a better choice to the patients. However, there are many shortcomings in the existing synthesis route of RPV, such as the high cost, prolonged reaction time and low yield (18.5%).ResultsThis article describes our efforts to develop an efficient and practical microwave-promoted method to synthesize rilpivirine using less toxic organic reagents and low boiling solvents. The last step's reaction time decreased from 69 h to 90 min through this optimized synthetic procedure, and the overall yield improved from 18.5 to 21%. In addition, the yield of intermediate 3 increased from 52 to 62% compared to the original patent.ConclusionOverall, through a series of process optimization, we have developed a practical synthesis method of rilpivirine, which is easy to scale with higher yield and shorter reaction time.

Meso to Neoproterozoic polyphase rifting and tectonic inversion: The example of the São João del Rei region at the southern border of the São Francisco Craton, Brazil

The up to 3000 m thick Mesoproterozoic and Neoproterozoic sedimentary succession exposed at the southern border of the São Francisco Craton, São João del Rei region (southern Minas Gerais State, Brazil), records the stacking of five sedimentary basins. These basins evolved due to multiple rifting episodes related to the southernmost Espinhaço rift system and were deformed around 600 Ma during the evolution of the Ribeira Orogen. These basins are the 1- São João del Rei Basin with quartzite units with maximum depositional age of ca. 1.5 Ga preserved in a half graben associated to the younger rift phases, 2- Carandaí Basin with rift related fault bounded debris flow deposits with maximum depositional age of ca. 1.38 Ga, and a sag carbonate infill recording the post-rift thermal relaxation, 3- Prados Basin, an NE-SW aulacogen linked to the passive margin Andrelândia Basin (<1.04 Ga) and 4- a foreland basin of the Brasiliano Orogeny with early syn-collisional plagioclase wacke deposits with maximum depositional age of ca. 650 Ma. The present paper discusses the role of the faults at the São João del Rei region in the evolution of these basins and the subsequent orogenic deformation. Five phases of fault activity were recognized. The first one is recorded by a few E-W faults and a single N–S fault and associated growth strata within the São João del Rei Basin. The second phase is recorded by activity of NE-SW, E-W and minor NW-SE faults during the Carandaí rifting (1.53–1.38 Ga). The main faults are the NW-SE Lenheiro and São João del Rei faults and the E-W São José Fault. Minor NW-SE faults are interpreted as release faults associated with the last two faults. NE-SW mafic dikes occurring along the faults suggest precursor/coeval magmatism. The third phase is characterized mainly by the reactivation of the NW-SE Lenheiro Fault leading to the development of the NW-SE Prados aulocogen. The fourth phase is inferred to be a reverse reactivation of NW-SE faults related to the NW tectonic transport direction of the Ribeira Orogen. The NW verging D1 folds and steeply SE dipping cleavage contribute to this interpretation. However, the reverse reactivation was insufficient to overcome the cumulative previous normal throw. During the fifth phase NE-SW faults were reactivated as dextral shear zones. Subhorizontal stretching lineation and mylonitic foliation occur along the Lenheiro Fault for at least 60 km. These structures are related to the E-W compression that generated other NE-SW regional dextral shear zones, such as the Três Corações and Caxambu shear zones during the late stages of the Brasiliano Orogeny. Structural data also reveals that during the Carandaí and/or Prados rifting, prior to the orogenic contraction, rotational oblique tilting in what was to become the northern limb of the Lenheiro Anticline generated the difference between the trends of the Beta axis and L1 in the northern limb of the anticline in relation to the other structural domains. This also explains the ENE-WSW trend of the Lenheiro Anticline contrasting with the NE-SW trend of the Águas Santas Syncline and of the other D1 regional folds south of the studied area. A forward model based on a cross section through the Águas Santas Syncline reveals that the NE-SW Lenheiro Fault acted as a major listric fault responsible for the development of a rollover anticline and the half-graben in which the São João del Rei basin deposits are preserved. Rotation and partial erosion of the hanging wall resulted in the deposition of the Carandaí diamictites in angular unconformity on the São João del Rei basin deposits. The model indicates 41% of total extension with a cumulative displacement of 4.2 km produced by the Carandaí and Prados rifting phases. The minimum shortening of the orogenic compressive phase is estimated to be about 11% with 1.57 km of displacement. These values may be underestimated since the model does not take into account parasitic folds, crystalplastic deformation and volume loss produced by layer parallel shortening and metamorphic reactions.

In Situ Generated Nickel Phosphide Based Catalysts for Hydroprocessing of Levulinic Acid

This article describes the production of unsupported nickel phosphide\t\t\t\t\tcatalysts generated in situ in а reaction mixture from water-soluble and\t\t\t\t\toil-soluble precursors during the hydroconversion of levulinic acid. These\t\t\t\t\tcatalysts contain crystalline phases, specifically\t\t\t\t\t\tNi12P5 and\t\t\t\t\t\tNi(PO3)2. During the\t\t\t\t\thydrogenation of levulinic acid in toluene in the presence of NiP–TOP, a lower\t\t\t\t\ttemperature and a shorter reaction time contribute to the formation of\t\t\t\t\tγ-valerolactone (100% selectivity). A higher temperature and a longer reaction\t\t\t\t\ttime favor the formation of valeric acid (94% selectivity). In the hydrogenation\t\t\t\t\tof levulinic acid in ethanol in the presence of\t\t\t\t\t\tNiP–H3PO2, the main reaction\t\t\t\t\tproduct is ethyl levulinate (95% selectivity).

Mental rotation performance and circadian chronotype in university students: a preliminary study

ABSTRACT The present study aimed to explore the influence of the chronotype on mental rotation performance in university students. Using the Morningness-Eveningness Questionnaire (MEQ), 24 healthy volunteers were categorized as either early chronotype (ECT) or late chronotype (LCT). Participants completed a chronometric mental rotation task with three-dimensional stimuli at different times of day (8 AM and 8 PM). ECT participants showed a shorter reaction time in the morning trial than in the evening (p = 0.003), whereas LCT participants showed a shorter reaction time (p = 0.001) and increased accuracy (p = 0.031) in the evening compared to the morning session. Additionally, the MEQ score was positively correlated with the difference in reaction time between morning and evening trials (r = −0.589, p = 0.002). Two-way analysis of variance revealed an interaction between time and chronotype for the parameter reaction time in the evening trials (F(1, 22) = 28.27, p < 0.001). LCT participants showed higher speed and increased accuracy during their optimal time compared to ECT participants. This study explored diurnal alterations of visual-spatial abilities assessed as mental rotation performance, and the possible implications for certain life skills such as sports, car driving, and manual labor are discussed.

Enhanced fatty acid methyl esters recovery through a simple and rapid direct transesterification of freshly harvested biomass of Chlorella vulgaris and Messastrum gracile

Conventional microalgae oil extraction applies physicochemical destruction of dry cell biomass prior to transesterification process to produce fatty acid methyl esters (FAMEs). This report presents a simple and rapid direct transesterification (DT) method for FAMEs production and fatty acid profiling of microalgae using freshly harvested biomass. Results revealed that the FAMEs recovered from Chlorella vulgaris were 50.1 and 68.3 mg with conventional oil-extraction-transesterification (OET) and DT method, respectively. While for Messastrum gracile, the FAMEs recovered, were 49.9 and 76.3 mg, respectively with OET and DT methods. This demonstrated that the DT method increased FAMEs recovery by 36.4% and 53.0% from C. vulgaris and M. gracile, respectively, as compared to OET method. Additionally, the DT method recovered a significantly higher amount of palmitic (C16:0) and stearic (C18:0) acids from both species, which indicated the important role of these fatty acids in the membranes of cells and organelles. The DT method performed very well using a small volume (5 mL) of fresh biomass coupled with a shorter reaction time (~ 15 min), thus making real-time monitoring of FAMEs and fatty acid accumulation in microalgae culture feasible.

Efficient Synthesis and Evaluation of Ultrasonic Assisted 1, 3-oxazin-2- amines as Encouraging Agents

Aims: 1,3- Oxazine-2-amines synthesized by sonochemical method using green catalyst lithium hydroxide monohydrate to enhance effect in reaction time when compared to traditional methods under acoustic energy. Background: Hostile to microbials accept a noteworthy activity in the treatment of infections to the individuals and at the same time, strange, medication of higher enemy of contamination changes protections in the quality level and may turn into the purpose for the anti-microbial opposition. Objectives: In this assignment, an undertaking has been made to join a couple of auxiliaries of 1, 3- oxazine-2-amines by ultrasonic irradiation with shorter reaction time also their in vitro screening was coordinated against Mycobacterium tuberculosis, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Aspergillus niger and Candida albicans. Methods: Five compounds were produced by under ultrasonic illumination within the use of lithium hydroxide monohydrate (LiOH.H2O) as a catalyst, which gave the items in great yields after short response times under mellow conditions The proposed concoction structures were affirmed by various spectroscopic systems like FTIR, 1H NMR and Mass spectroscopy. TLC was utilized to realize that the reactants were depleted and the development of the item happened. Sharp melting point of the compounds concludes the purity. All the molecules assessed for in vitro antibacterial and antifungal exercises. Antibacterial and antifungal exercises were tried utilizing the agar dispersion technique. Results: From the screening thinks about it was seen that a large portion of the compounds have indicated moderate antibacterial and antifungal inhibition at 500 μg/mL and 100 μg/mL fixations individually. The MIC of the molecules like C (Chloro), N (Nitro) demonstrated promising activity at the conenctration of 1.6 μg/ml and F (Fluoro) – 3.12 μg/ml when appeared differently in relation to measures like Pyrazinamide-3.125μg/ml, Ciprofloxacin 3.125μg/ml, Streptomycin-6.25μg/ml against Mycobacterium tuberculosis. Conclusion: The results are extremely promising which on further assessments may provoke medicine particles against different microorganisms. Especially, C, N can be considered as a far reaching range master due to its solid development against different microorganisms like Mycobacterium tuberculosis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and Candida albicans.

Short Term Reactions on the Bucharest Stock Exchange before and during Coronavirus Pandemic

Short Term Reactions on the Bucharest Stock Exchange before and during Coronavirus Pandemic

Bioconversion of Methanol by Synthetic Methylotrophy.

As an important building block in the chemical industry, methanol has become an attractive substrate in biorefinery owing to its abundance and low cost. With the development of synthetic biology, metabolic engineering of non-methylotrophy to construct synthetic methylotrophy has drawn increased attention. As for the metabolic construction of methanol assimilation pathway in some industrial hosts, several artificial methanol assimilation pathways have recently been designed and constructed based on the computer-aided design. Particularly, these artificial methanol assimilation pathways possess advantages of shorter reaction steps, stronger driving forces, and independence on oxygen. Accordingly, this chapter reviewed strategies of constructing synthetic methylotrophs, including introducing methanol metabolic modules derived from natural methylotrophs and designing artificial methanol assimilation pathways. Future challenges and prospects were also discussed.

Microwave Assisted Envirocat EPZ-10 Catalyzed Multi-component Synthesis of 1-Amidoalkyl-2-naphthols

Microwave assisted catalytic efficiency of Envirocat EPZ-10 was explored in solvent free green synthesis of 1-amidoalkyl-2-naphthols by the reaction of aldehyde, 2-naphthol and acetamide. The products formed were characterized by spectroscopic methods such as NMR, IR and mass spectroscopy. The merits of developed synthetic method are use of Envirocat EPZ-10 as eco-friendly, reusable and heterogeneous catalysts, solvent-free reaction, shorter reaction time and easy isolation of product.

Effects of creative expression program on the event-related potential and task reaction time of elderly with mild cognitive impairment

ObjectivesThis study aimed to evaluate the effects of a 16-week creative expression intervention program (CrExp) on the event-related potential (ERP) and task reaction time in older individuals with mild cognitive impairment (MCI). MethodsThis study is a randomized controlled clinical trial conducted in the Memory Center of Fujian Provincial hospital. Thirty-six MCI patients were randomly distributed into two groups. One group underwent a 16-week creative expression program (CrExp, n = 18) and the other performed as a control group (CG, n = 18) by general social activities. The amplitude and latency of ERP-P300 from the central (Cz), parietal (Pz), frontal (Fz) cortices and task reaction time (RT) were assessed at baseline, post-interventi on, and 24-week follow-up. ResultsThe CrExp group showed greater differences than CG of P300 latency in Cz (F = 4.37, P = 0.015), Pz (F = 2.78, P = 0.009), Fz (F = 6.45, P = 0.031) brain area after 16 weeks of intervention and in Fz (F = 3.23, P = 0.028), Cz (F = 3.79, P = 0.024), and Pz (F = 5.60, P = 0.036) at 24 weeks follow-up. Also, we analyzed the task reaction time between two groups and found that a shorten reaction time at post-intervention (F = 4.47, P = 0.011) and 24 weeks follow-up (F = 3.12, P = 0.007) in the CrExp group. However, there was no difference in P300 amplitude in either brain area between the two groups. ConclusionThe electrophysiological results of the creative expression cognitive therapy group were more obvious than those of the general cognitive therapy group, and the latency and task reaction time may be considered as supported parameters in diagnosing the effects during non-drug therapy intervention in clinical practice.

Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives.

This work describes an efficient, simple, and ecofriendly sonochemical procedure for the preparation of new α-(arylamino)acetonitrile derivatives C-substituted with phenothiazine or ferrocene units. The synthetic protocol is based on the Strecker reaction of a (hetero)aryl aldimine substrate with trimethylsilyl cyanide (TMSCN) in poly(ethylene glycol) (PEG) solution. The advantages of the sonochemical versus the conventional α-(arylamino)acetonitrile synthesis are the significantly shorter reaction time (30 min instead of 72 hours), the higher purity and the easier separation of the product that precipitated from the reaction mixture in crystalline form as depicted by scanning electron microscopy (SEM) analysis. The single crystal X-ray diffraction analysis disclosed the arrangement of the α-(arylamino)acetonitrile molecules in the aggregated crystalline state as a racemic mixture. The mutagenic/antimutagenic potential for three representative derivatives containing phenothiazinyl, ferrocenyl, and phenyl units, respectively, was evaluated by the Ames Salmonella/microsome test using S. typhimurium TA98 and TA100 strains with and without metabolic activation. The preliminary screening results pointed out that the C-(hetero)aryl-α-(arylamino)acetonitrile derivatives can be considered genotoxically safe and possibly antimutagenic.

Mechanochemical P-derivatization of 1,3,5-Triaza-7-Phosphaadamantane (PTA) and Silver-Based Coordination Polymers Obtained from the Resulting Phosphabetaines.

We have described earlier that in aqueous solutions, the reaction of 1,3,5-triaza-7-phosphaadamantane (PTA) with maleic acid yielded a phosphonium-alkanoate zwitterion. The same reaction with 2-methylmaleic acid (citraconic acid) proceeded much slower. It is reported here, that in the case of glutaconic and itaconic acids (constitutional isomers of citraconic acid), formation of the corresponding phosphabetaines requires significantly shorter reaction times. The new phosphabetaines were isolated and characterized by elemental analysis, multinuclear NMR spectroscopy and ESI-MS spectrometry. Furthermore, their molecular structures in the solid state were determined by single crystal X-ray diffraction (SC-XRD). Synthesis of the phosphabetaines from PTA and unsaturated dicarboxylic acids was also carried out mechanochemically with the use of a planetary ball mill, and the characteristics of the syntheses in solvent and under solvent-free conditions were compared. In aqueous solutions, the reaction of the new phosphabetaines with Ag(CF3SO3) yielded Ag(I)-based coordination polymers. According to the SC-XRD results, in these polymers the Ag(I)-ion coordinates to the N and O donor atoms of the ligands; however, Ag(I)-Ag(I) interactions were also identified. The Ag(I)-based coordination polymer (CP1.2) formed with the glutaconyl derivative of PTA (1) showed considerable antimicrobial activity against both Gram-negative and Gram-positive bacteria and yeast strains

Optimisation of accelerated biodiesel production under near infrared radiation from de-oiled mustard and sunflower cakes

ABSTRACT An energy-efficient intensification protocol for biodiesel (fatty acid ethyl ester (FAEE)) production from the mustard de-oiled cake (MDC) and sunflower de-oiled cake (SDC) through concurrent esterification-transesterification reactions has been disclosed employing near-infrared radiation retrofitted batch reactor. The triglycerides and free fatty acids of the de-oiled cake were converted to FAEE through a one-pot synthesis in the presence of ethanol and one of the co-solvents viz. acetone, dimethyl sulfoxide (DMSO), and n-hexane. The optimal condition (75:1 (w/w) ethanol to de-oiled cake ratio, 70°C infrared radiation temperature, 2.5 wt. % H2SO4 catalyst concentration, and 1000 rpm stirrer speed) for maximum FAEE yield was evaluated deploying Taguchi L9 orthogonal method. Higher FAEE yield was achieved under infrared radiation for both MDC (82.4 ± 0.01%) and SDC (81.7 ± 0.02%), in comparison with the conventionally heated reactor (MDC: 56.1 ± 0.02%; SDC: 54 ± 0.02%) employing identical process condition. This enlightened the energy-efficacy of the infrared radiation in accelerating the FAEE yield within a much shorter reaction time. The FAEE composition was assessed by FTIR and GC-MS analyses. The fuel properties of the product biodiesel conformed to EN standards. Thus, a feasible and efficient protocol for the conversion of de-oiled cakes to biodiesel could be explored.

Memory of chirality in a room temperature flow electrochemical reactor

Chiral compounds have become of great interest to the pharmaceutical industry as they possess various biological activities. Concurrently, the concept of “memory of chirality” has been proven as a powerful tool in asymmetric synthesis, while flow chemistry has begun its rise as a new enabling technology to add to the ever increasing arsenal of techniques available to the modern day chemist. Here, we have employed a new simple electrochemical microreactor design to oxidise an l-proline derivative at room temperature in continuous flow. Compared to batch, organic electrosynthesis via microflow reactors are advantageous because they allow shorter reaction times, optimization and scale up, safer working environments, and high selectivities (e.g. reduce overoxidation). Flow electrochemical reactors also provide high surface-to-volume ratios and impart the possibility of excluding the supporting electrolyte due to a very short interelectrode distance. By the comparison of Hofer Moest type electrochemical oxidations at room temperature in batch and flow, we conclude that continuous flow electrolysis is superior to batch, producing a good yield (71%) and a higher enantiomeric excess (64%). These results show that continuous flow has the potential to act as a new enabling technology for asymmetric synthesis to replace some aspects of conventional batch electrochemical processes.

The Relationship Between Physical Activity and Inhibition in Children With and Without Motor Impairments.

To examine the relationship between physical activity (PA) and inhibition in boys and girls with motor impairments compared with children with typical development. The participants were 58 (26 motor impairments and 32 typical development) children aged 7-12 years who met the inclusion criteria. PA was assessed using accelerometers for 7 consecutive days. The time spent in PA of different intensity levels (light, moderate, and vigorous) were analyzed for weekdays and weekends. Using a visuospatial attention paradigm, inhibition was evaluated by the difference in reaction time between invalid and valid cue conditions. Generalized linear mixed models were used to determine the associations of inhibition with PA and motor ability by sex. Boys and children with typical development had shorter reaction times in inhibition than girls (P < .001) and children with motor impairments (P < .05), respectively. Motor ability (b = 189.98) and vigorous PA on weekdays (b = -43.18) were significant predictors of inhibition in girls only. The results indicate a positive relationship between vigorous PA (on weekdays) and inhibition in children (girls), moderated by sex and motor ability. Effective interventions that promote vigorous PA for children both in and out of school should be designed to foster their executive function development.

Plasmin thrombelastography rapidly identifies trauma patients at risk for massive transfusion, mortality, and hyperfibrinolysis: A diagnostic tool to resolve an international debate on tranexamic acid?

Trauma patients with hyperfibrinolysis and depletion of fibrinolytic inhibitors (DFIs) measured by thrombelastography (TEG) gain clot strength with TXA, but TEG results take nearly an hour. We aimed to develop an assay, plasmin TEG (P-TEG), to more expeditiously stratify risk for massive transfusion (MT), mortality, and hyperfibrinolysis. Trauma patients (N = 148) were assessed using TEG assays without exogenous additives (rapid/native), with exogenous plasmin (P-TEG) or tissue plasminogen activator (tPA TEG). The plasmin dose used does not effect healthy-control clot lysis 30 minutes after maximum amplitude (LY30) but causes shortened reaction time (R time) relative to native TEG (P-TEG R time < native TEG R time considered P-TEG negative). If P-TEG R time is greater than or equal to native TEG R time, the patient was considered P-TEG positive. Each assay's ability to predict MT, mortality, and (risk for) hyperfibrinolysis was determined. χ and Mann-Whitney U tests were used to compare categorical and continuous variables, respectively. Results were reported as median ± interquartile range or n (%). Plasmin TEG provided results faster than all other assays (4.7 ± 2.5-9.1 minutes), approximately 11-fold faster than rapid-TEG (rTEG) LY30 (54.2 ± 51.1-58.1 minutes; p < 0.001). Plasmin TEG-positive patients had greater than fourfold higher MT rate (30% vs. 7%; p = 0.0015) with an area under the receiver operating characteristic curve of 0.686 (p = 0.028), greater than fourfold higher 24-hour mortality (33.3% vs. 7.8%; p = 0.0177), greater than twofold higher 30-day mortality (35% vs. 16.4%; p = 0.0483), higher rates of DFI (55% vs. 18%; p < 0.001), and a trend toward elevated D-dimer (19.9 vs. 3.3 μg/mL; p = 0.14). Plasmin TEG was associated with hyperfibrinolysis on rTEG LY30 at the 7.6% threshold (p = 0.04) but not the 3% threshold (p = 0.40). Plasmin TEG performed best in relation to DFI, with a positive predictive value of 58% and negative predictive value of 81%. When combined with tPA TEG time to maximum amplitude, P-TEG outperformed rTEG LY30 for predicting MT (area under the receiver operating characteristic curve, 0.811 vs. 0.708). Within 5 minutes, P-TEG can stratify patients at highest risk for MT, mortality, and risk for hyperfibrinolysis. In composite with tPA TEG time to maximum amplitude, P-TEG outperforms rTEG LY30 for predicting MT and does so four times faster (12.7 vs. 54.1 minutes). The rapid results of P-TEG may be useful for those who practice selective TXA administration to maximize TXA's time-dependent efficacy. Diagnostic test, level V.

Synthesis of 2,5-disubstituted-1,3,4-thiadiazole derivatives from (2S)-3-(benzyloxy)-2-[(tert-butoxycarbonyl) amino] propanoic acid and evaluation of anti-microbial activity

The new compounds AP-1 to AP-10 were synthesized from starting material (2S)-3-(benzyloxy)-2-[(tert-butoxycarbonyl) amino]propanoic acid (1). The intermediate 2,5-disubstituted-1,3,4-thiadiazole amine (5) was prepared by coupling of (2S)-3-(Benzyloxy)-2-[(tert-butoxycarbonyl) amino]propanoic acid (1) with pyridine-2-carboxylic acid hydrazide (2) in the presence of carbonyldiimidazole (CDI) followed by 1,3,4-thiadiazole ring formation via diacylhydrazines derivative (3) and deprotection with shorter reaction time and excellent yield. The structures of new compounds were confirmed by spectral analysis. The series of new synthesized compounds AP-1 to AP-10 were evaluated for their anti-microbial activities in vitro and compounds AP-1, AP-3, AP-4, and AP-10 showed strong activities against all tested microorganisms.

Field-Oriented Driving/Braking Control for Electric Vehicles

Most electric vehicles use regenerative brakes, since this kind of braking system design recycles electromotive force to increase electric power endurance during braking. This research proposes a sensor-free, integrated driving and braking control system that uses a space-vector-pulse-width module to synthesize stator current by purpose. It calculates the rotor position angle of the motor by detecting variation in the stator current and completes a closed-loop control. When the motor receives a brake command, the controller changes the inverter-switching sequence to generate reverse torque and a magnetic field to complete the driving or braking function using field-oriented control (FOC). This provides a smoother and more accurate motor control than sinusoidal commands with Hall feedback. Compared to the regenerative brake and rheostatic brake, the proposed braking system has a powerful braking torque and shorter reaction time. Comparisons of reaction times for a modified four-wheel electric vehicle equipped with a permanent magnet synchronous motor under neutral-sliding-status, FOC based braking, and short-circuit braking were conducted.