bluuebunny/crossref_metadata_2025 huggingface dataset:
Do hotel industry operations deteriorate air quality?
Authors: Wang Liang-Ju , Chen Ming-Hsiang , Yang Zhandong , Su Ching-Hui (Joan)
Published: June 2021

This study proposes and tests two hypotheses concerning the effects of hotel industry operations on air quality based on data of 26 major tourist cities in China from 2002 to 2017. The empirical analyses take two steps. In the first step, panel regression test results reveal that hotel industry operations (measured by hotel sales revenue) significantly raise the value of particulate matter (PM)2.5 (the key indicator of air quality), supporting the first hypothesis that hotel industry operations deteriorate air quality and providing empirical evidence of the adverse impact of the hotel industry on air quality. In the second step, subsample analyses support the second hypothesis that the impact of hotel sales revenue on air quality diminishes over time. The results from the rolling regression tests validate the existence of a diminishing effect of hotel industry operations on air quality.
The impact of the COVID-19 pandemic on revenues of visitor attractions: An exploratory and preliminary study in China
Authors: Wang Ling-en , Tian Bing , Filimonau Viachaslau , Ning Zhizhong , Yang Xuechun
Published: June 2021

The COVID-19 pandemic has made a detrimental impact on various tourism subsectors. The financial consequences of this impact should be carefully evaluated to set benchmarks for industry recovery. This study assessed the financial impact of the pandemic on the tourism subsector of visitor attractions in China; 4222 A-grade visitor attractions accounting for over one-third of the national market were surveyed. Data triangulation was subsequently applied to undertake a comprehensive assessment of potential revenue loss. Triangulation was based upon the (1) lost revenue estimates made by tourist attractions’ administrations, (2) reverse estimation of past macroeconomic data, and (3) expert opinion estimates. The assessment results demonstrated that A-grade visitor attractions in China may have lost up to 140 billion RMB (circa US$21 billion) due to COVID-19, with up to 65% of all losses incurred in the first quarter of 2020. The scale of revenue loss varied significantly depending on visitor attraction’s grade, type, and location. Potential strategies for industry recovery are discussed.
Cognitive vs. metacognitive scaffolding strategies and EFL learners’ listening comprehension development
Authors: Ahmadi Safa Mohammad , Motaghi Fateme
Published: June 2021

Studies have documented the significance of scaffolding as a sociocultural theory driven type of assistance for the development of English as foreign language (EFL) learners’ language skills in general; however, the comparative efficacy of various cognitive and/or metacognitive scaffolding procedures for EFL learners’ listening comprehension development and progress has received scant attention. As a partial attempt in this regard, this study investigated the comparative efficacy of cognitive and metacognitive scaffolding strategies for EFL learners’ listening comprehension development. For this purpose, 90 intermediate level EFL learners aged 15 to 20 were selected to participate in this study. The participants’ actual proficiency level was assessed using a sample TOEFL Junior Standard test and relatively homogeneous classes of nearly 15 learners were formed and randomly assigned to two experimental conditions and a control one. The listening section of TOEFL Junior standard test was used as the pre- and posttest. While the learners in both experimental conditions worked in groups of three or four learners on some listening comprehension tasks, the participants of the first experimental condition received cognitive scaffolding strategies, and the second experimental group members were treated using metacognitive scaffolding strategies, the control group members received teacher-fronted non-scaffolding instruction. In addition to a listening comprehension posttest, a semi-structured interview was given to a number of participants of each experimental condition to explore their attitudes towards given scaffolding strategies. The analyses verified that metacognitive scaffolding strategies had a significant superior effect on EFL learners’ listening development compared to cognitive scaffolding strategies and non-scaffolding instruction. Furthermore, the analyses revealed that the EFL learners were generally more pleased with the metacognitive scaffolding procedures and viewed them as instructive, innovative, and effective for finding problems, better comprehension and increased readiness.
Seeing or acting? The effect of performing gestures on foreign language vocabulary learning
Authors: García-Gámez Ana B. , Cervilla Óscar , Casado Alba , Macizo Pedro
Published: June 2021

We evaluate the impact of gestures during the teaching of vocabulary in a foreign language (FL). Spanish speakers learned words in a FL in four gesture conditions according to the relationship between the meaning of the words and the gestures (congruent gestures, incongruent gestures, gestures without meaning, and no gestures). The participants learned the words by performing gestures (‘do’ teaching group) or by observing the gestures performed by others (‘see’ teaching group). Compared to the meaningless gesture condition, the processing of congruent gestures facilitated the recall of second language (L2) words in the ‘see’ and ‘do’ teaching groups. However, the interference effect associated with the processing of incongruent gestures was greater in the ‘see’ teaching group than in the ‘do’ teaching group. Thus, the performance of gestures seems to mitigate the negative impact that the use of gestures may have on the teaching of vocabulary in a foreign language.
(Un)tethered masculinities, (mis)placed modernities: Queering futurity in contemporary Singapore
Authors: Woods Orlando
Published: June 2021

This article considers how socio-political prescriptions can bring about the queering of futurity in Singapore. In Singapore, state-sponsored narratives of progress view futurity in terms that are bound to place, and reproduced through the heteronormative family unit. These factors have caused constructions of masculinity to be tethered to the family, and placed within public housing. Recently, this narrative has become an increasingly inflexible and marginalizing construct that can cause straight males to be queered by their prescribed futures. In contrast, gay males are more likely to be untethered from their families, and thus occupy “unplaced” positions in Singapore’s social structure.
The anti-authoritarian revolt: Right-wing populism as self-empowerment?
Authors: Lütjen Torben
Published: June 2021

Right-wing populism and authoritarianism are often thought to be closely linked to each other: conceptually, ideologically, historically. This article challenges that assumption by reinterpreting right-wing populism as an essentially anti-authoritarian movement. Right-wing populism diverges from the clearly authoritarian movements of the past, such as classic conservatism and fascism, in at least two important ways: first, it follows a distinctive epistemology with a different idea what constitutes the truth and who has access to it. Second, populism has a peculiar understanding of the ultimate source of political authority and the function of political leadership. My article shows how right-wing populists pursue a project of self-empowerment and appropriate notions of emancipation and autonomy for their own narrative.
Numerical investigation on moment redistribution of continuous reinforced concrete beams under local fire conditions
Authors: Li Zhe , Ding Fa-xing , Cheng Shanshan
Published: June 2021

This article presents a numerical investigation on the mechanical behaviours, such as the fire resistance, the moment redistribution and the failure mode, of continuous reinforced concrete beams with two spans and three spans under the standard fire of ISO-834. Firstly, a 3D finite element model was established and validated against the fire test beam. Secondly, the three stages associated with the fire time of fire behaviour for the continuous reinforced concrete beams were divided and explained. An index of the moment redistribution amplitude was modified and used to evaluate the fire performance of continuous reinforced concrete beams. A series of parametric analyses for continuous reinforced concrete beams with two spans were conducted in order to investigate the influence of some parameters such as the load ratio, the load position, the support condition and the sectional size. Finally, the distributions of the vertical deflection and the plastic hinge within beam spans and the failure modes for continuous reinforced concrete beams with three spans under local fire conditions were discussed emphatically.
Exact solutions of Hirota–Maccari system forced by multiplicative noise in the Itô sense
Authors: Mohammed Wael W. , Ahmad Hijaz , Boulares Hamid , Khelifi Fathi , El-Morshedy Mahmoud
Published: June 2021

In this article, the stochastic Hirota–Maccari system forced in the Itô sense by multiplicative noise is considered. We just use the He’s semi-inverse method, sine–cosine method, and Riccati–Bernoulli sub-ODE method to get new stochastic solutions which are hyperbolic, trigonometric, and rational. The major benefit of these three approaches is that they can be used to solve similar models. Furthermore, we plot 3D surfaces of analytical solutions obtained in this article by using MATLAB to illustrate the effect of multiplicative noise on the exact solution of the Hirota–Maccari method.
When Falling Just Short is a Good Thing: The Effect of Past Performance on Improvement
Authors: Burdina Mariya , Hiller Scott
Published: June 2021

Models of reference-dependent preferences show that an individual’s utility depends on the difference between the outcome and a “neutral” reference point. Our paper investigates how distance from reference points affects future performance. We find that round numbers and personal bests motivate runners and that missing the goal by a small amount improves future performance. For those who achieve their goal, future performance suffers slightly. In empirical analysis, we use an extensive panel of marathon data, which contains a past running history for every runner in our sample and allows us to estimate runners’ ability and experience.
The Amenity Value of Sports Facilities: Evidence From the Staples Center in Los Angeles
Authors: Keeler Zachary T. , Stephens Heather M. , Humphreys Brad R.
Published: June 2021

U.S. cities have recently experienced a boom in new sports facility construction. Although these facilities can provide benefits to local residents, they may also generate negative externalities, making dwellings near a facility less desirable. Using a hedonic spatial difference-in-differences model, we analyze the impact of proximity to the Staples Center, a sports and entertainment venue in downtown Los Angeles, California, on house prices. Results indicate that the arena opening increased nearby house prices and that there were also positive “anticipation” effects associated with the announcement of the new arena location and local government approval.
Biological, Nutritional, and Social Factors Associated with Intra-Uterine Growth Retardation in Mexico City
Authors: Balcazar Hector , Cobas José A.
Published: June 2021

This study investigates the relationship between maternal biological, nutritional, and socio-demographic variables as they relate to intra-uterine growth retardation (IUGR) in 162 women who delivered in a maternal and child centre in Mexico City. Data were obtained through a questionnaire administered to each woman after her infant was born. The mothers’ height, arm and head circumferences, and skinfolds were measured after delivery. Infants were defined as having IUGR if their gestational age was 37 weeks or over and their birth weight was at or below the 10th percentile of a sex-specific birth weight-gestational age distribution of a reference population. Infants whose gestational age was 37 weeks or over and whose birth weight was above the 10th percentile of the reference population distribution were defined as having normal birth weight. Overall, maternal risk factors associated with past and current nutritional status were associated with IUGR, but social factors were not. Logistic regression analysis showed that height, positive dietary changes during pregnancy, and past spontaneous abortions during the second trimester were significantly related to IUGR.
Food Security Issues Associated with Development in Thailand
Authors: Kachondham Yongyout
Published: June 2021

Thailand has sustained economic growth and generated an increase in national/and per capita income, but income distribution and poverty profiles remain major concerns. The prevalence of protein-energy malnutrition (PEM) in children under five years of age was 53% between 1979 and 1982 and 23.5% in 1987. Although there has been a marked improvement as a result of the nationwide growth-monitoring and community-based nutrition programmes of the Ministry of Public Health, PEM and micro-nutrient deficiencies still undermine the quality of Thailand's future human resources in vulnerable groups. Moreover, Thailand is facing new nutrition-related health threats, including heart disease, hypertension, and certain types of cancer. Meeting the food security and dietary needs of people depends on improvement in every link of the food chain, including research, training, and technology development in food production, food storage and distribution, nutrition and public health, income distribution, education, and food and nutrition policy.
Current World Supplies of and Requirements for Essential Amino Acids
Authors: Kazuo Hoshiai
Published: June 2021

Correlations of GDP per capita per year with total protein supplies per capita per day and animal-protein ratios were computed by pooling data prom 164 countries. Average supplies for 1972–1974, 1975–1977, 1979–1981, and 1984–1986 were determined from FAO food balances sheets. Essential amino acid (EAA) supplies by country were computed using amino acid data for food commodities shown in FAO food balance sheets and other data. The EAA requirements for the four periods were estimated by country. When the latest amino acid requirement estimates are used, lysine is the limiting amino acid in all predominantly cereal diets.
Visceral segment aortic thrombus is associated with proximal aortic degeneration after infrarenal abdominal aortic aneurysm repair
Authors: Steenberge Sean P , Clair Daniel G , Eagleton Matthew J , Caputo Francis J , Smolock Christopher J , Lyden Sean P
Published: June 2021

Objective

To identify predictors of aortic aneurysm formation at or above an infrarenal abdominal aortic aneurysm repair.

Methods

A total of 881 infrarenal abdominal aortic aneurysm repairs were identified at a single institution from 2004 to 2008; 187 of the repairs were identified that had pre-operative and post-operative computed tomography imaging at least one year or greater to evaluate for aortic degeneration following repair. Aortic diameters at the celiac, superior mesenteric, and renal arteries were measured on all available computed tomographic scans. Aortic thrombus and calcification volumes in the visceral and infrarenal abdominal aortic segments were calculated. Multivariable modeling was used with log transformed variables to determine potential predictors of future aortic aneurysm development after infrarenal abdominal aortic aneurysm repair.

Results

Of the 187 patients in the cohort, 100 had an open abdominal aortic aneurysm repair while 87 were treated with endovascular repair. Proximal aortic aneurysms developed in 26% ( n = 49) of the cohort during an average of 72 ± 34.2 months of follow-up. After multivariable modeling, visceral segment aortic thrombus on pre-operative computed tomography imaging increased the risk of aortic aneurysm development above the infrarenal abdominal aortic aneurysm repair within both the open abdominal aortic aneurysm (hazard ratio 2.04, p = 0.033) and endovascular repair (hazard ratio 3.31, p = 0.004) cohorts. Endovascular repair was independently associated with a higher risk of future aortic aneurysm development after infrarenal abdominal aortic aneurysm repair when compared to open abdominal aortic aneurysm (hazard ratio 2.19, p = 0.025).

Conclusions

Visceral aortic thrombus present prior to abdominal aortic aneurysm repair and endovascular repair are both associated with an increased risk of future proximal aortic degeneration after infrarenal abdominal aortic aneurysm repair. These factors may predict patients at higher risk of developing proximal aortic aneurysms that may require complex aortic repairs.
The anatomy of CUSMA’s patent: Does it still reflect an equipoise?
Authors: Boru Zeleke Temesgen
Published: June 2021

The Protocol of Amendment to the Agreement between the United States of America, Canada and the United Mexican States erased many of the TRIPS-plus provisions inserted earlier into the Canada- United States of America-Mexico Agreement (hereafter, CUSMA) signed on 30 November 2018. While the erasure of the provisions shows the contributions made to promote access to medicines, the Agreement still retains TRIPS-plus provisions, including the provisions on patent term extensions. Thus seen, irrespective of the changes introduced by the Protocol of Amendment, patent term extensions may have a negative implication on access to cost-cutting medicines (biosimilars and generics).

Against this backdrop, this paper focuses on patent term extensions, as contained in the CUSMA’s Intellectual Property Rights (IPRs) chapter. The paper investigates if & how the patent term extension has the potential to impede access to affordable medicines (biologics and chemically synthesized medicines). In so doing, the paper provides possible responses to the question, do the provisions on patent term extensions hinder the timely access to affordable medicines? As such, the first part of the paper succinctly looks at CUSMA. Section “Patent protection under the TRIPS agreement” examines the TRIPS patent regime. While “The CUSMA’s rules on patent term extension” section discusses the nature of obligations included in the CUSMA’s IPRs chapter, the Section “The CUSMA’s rules on patent term extension vis-à-vis access to medicines” analyzes the potential implications of patent term extensions on access to affordable medicines. The final section concludes the paper.
Adaptive assessment of the capacity of cognitive control
Authors: He Xu , Qiu Boyu , Deng Yingyu , Liu Ting , Chen Yanrong , Zhang Wei
Published: June 2021

Cognitive control, although it has limited capacity, serves an essential role in supporting a broad range of cognitive functions. The backward masking majority function task (MFT-M) is a validated behavioural method for measuring the capacity of cognitive control (CCC), but the administration is lengthy. We tested the relative efficiency of administering the MFT-M using an adaptive method based on the principles of computerised adaptive testing (CAT). Participants were 40 healthy young adults aged 18–26. Scores on the adaptive version were highly correlated with scores based on the original approach to administration and showed high test–retest reliability. In addition, compared with the original task of 864 trials (about 86 min), less than 216 trials (20 min) were required in the adaptive version. The results suggest that CAT is a valid and more efficient method for assessing CCC than the MFT-M. This study provides an example of adaptive trial selection in task administration, an approach that can advance the methodology of behavioural science.
A Novel and Efficient Method for the Synthesis of N-Arylsulfonylamino-2-pyridones
Authors: Elgemeie Galal H. , Elghandour Ahmed H. H. , Ali Hosny A. , Abdel-Azzez Hassan M.
Published: June 2021

A novel and efficient method for the synthesis of N-arylsulfonylamino-2-pyridones, via the reaction of N-cyanoaceto-hydrazides with ethyl arylidenecyanoacetate derivatives, is investigated; N-sulfonated aminopyridines are also prepared from the reaction of N-amino-2-pyridones with arylsulfonyl chlorides.
Reaction of Carbon Disulfide with Cyanoacetic Acid Hydrazide: Novel Synthesis of Thiazole and Thiazolo[4,5-c]pyrazole
Authors: Mohareb Rafat M. , Aziz Suzan I. , Abdel-Sayed Nadia I. , El-Banna Ahmed H.
Published: June 2021

The reaction of cyanoacetic acid hydrazide with carbon disulfide in basic dimethylformamide afforded the potassium thiocarbamate 2 which underwent ready heterocyclization upon its reaction with α-haloketones to give the thiazole derivatives 4 and 23.
The Classical Structure of TaCp2(H)(SiMe2H)2
Authors: Tanaka Ichiro , Ohhara Takashi , Niimura Nobuo , Ohashi Yuji , Jiang Qian , Berry Donald H. , Bau Robert
Published: June 2021

Neutron diffraction analysis of TaCp2(H)(SiMe2H)2 (1) has revealed a symmetric structure with a classical, rather than agostic, hydride ligand: the Ta–H distance is 1.785(15) Å, the non-bonding H···Si distances are 2.189(18) and 2.190(17) Å, and the H–Ta–Si angles are 55.2(5) and 55.5(5)°; final R factor = 8.9% for 1295 reflections.
3-(Phenylthio)Phthalide: An Expedient Reagent in Phthalide Annulation
Authors: Ghorai Sujit K. , Roy Harendra N. , Bandopadhyay Mousumi , Mal Dipakranjan
Published: June 2021

3-(Phenylthio)phthalide 4 is more readily accessible than the established reagents 1 and 2 and can be engaged in phthalide annulation with comparable efficacy.
Novel Synthesis of Protected Methyl 4-Hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate via Cleavage of Functionalized Dihydrooxazoles (Oxazolines)
Authors: Lerestif Jean Michel , Feuillet Soazig , Bazureau Jean Pierre , Hamelin Jack
Published: June 2021

The protected methyl 4-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate is synthesized by two convergent routes from dimethyl-5-(2-formylphenyl)-2-methyl-4,5-dihydrooxazole-4,4-dicarboxylate via cleavage of the oxazolyl moiety, the starting dihydrooxazole is prepared on a large scale at 70 °C by 1,3-dipolar cycloaddition using a solvent-free process assisted by focused microwave technology.
Cleavage of Protecting Groups Catalysed by π-Acceptors
Authors: Tanemura Kiyoshi , Nishida Yoko , Suzuki Tsuneo , Satsumabayashi Koko , Horaguchi Takaaki
Published: June 2021

The cleavage of protecting groups is caused by the acidic adducts produced from the methanolysis of acceptors.
Preparation and Structure of [Na.15-crown-5][Ni(mnt)2].H2O
Authors: Robertson Neil , Roehrs Stefan , Akutagawa Tomoyuki , Nakamura Takayoshi , Underhill Allan E.
Published: June 2021

The salt [Na.15-crown-5][Ni(mnt)2].H2O has been prepared by electrocrystallisation and characterised by X-ray crystallography showing a stacking arrangement of [Ni(mnt)2]- and a slipped stack arrangement of the crown ethers.
Facile Synthesis of Some Novel Dicarboxylic Acid Crown Ethers
Authors: Bate Andrea L. , Carter Thomas P. , Wheeler John W.
Published: June 2021

Two procedures for the synthesis of a series of novel dicarboxylic acid functionalised aza-crown ethers from dicarboxylic acid anhydrides and 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane are reported.
Oxidative Chlorination of Various lodoarenes to (Dichloroiodo)arenes with Chromium(vi) Oxide as the Oxidant
Authors: Kaźmierczak Pawet , Skulski Lech , Obeid Nicolas
Published: June 2021

Chromium(VI) oxide dissolved in a mixture of acetic acid with concentrated hydrochloric acid converts, at or near room temperature, iodoarenes to (dichloroiodo)arenes, in a very simple and efficient procedure.
Synthesis of (n5-R1C5H4)(CO)2Mo(n2-S2R) via Reaction of (μ-RS)(μ-p-MeC6H4SO2S)Fe2(CO)6 with Nucleophiles (n5-R1C5H4)(CO)3MoSeNa. Crystal Structure of (n5-MeO2CC5H4)(CO)2Mo(n2-S2But)
Authors: Song Li-Cheng , Hu Qing-Mei , Qin Xiang-Dong
Published: June 2021

The reaction of (μ-RS)(μ- p-MeC6H4SO2S)Fe2(CO)6 with ( n5-R1C5H4)(CO)3MoSeNa gave organomolybdenum complexes ( n5-R1C5H4)(CO)2Mo( n2-S2R) (3a R = Et, R1 = H; 3b R = But, R1 = MeO2C), the structure of 3b being determined by X-ray diffraction analysis.
Polycyclic N-Heterocyclic Compounds. Part 54. Ring-cleavages and Ring-closures of N-(Benzo[h]quinazolin-4-yl)amidine and its Amide Oxime Derivatives with Hydroxylamine
Authors: Sasaki Kenji , Zhang Ying-Xue , Yamamoto Hiroshi , Kashino Setsuo , Hirota Takashi
Published: June 2021

The synthesis of abnormal cyclization products, 2-(3-alkyl(or aryl)[1,2,4]oxadiazol-5-yl)-3,4-dihydro-1-naphthylaminoformaldehyde oximes and their homologues, by the reaction of N-(benzo[ h]quinazolin-4-yl)amidine or its amide oxime derivatives with excess NH2OH · HCI are described.
A Novel Synthesis of Cyclopenta[c]pyridazines and 1,8-Ethanophthalazinones: A New Ring System
Authors: Elassar Abdel-Zaher Abdel-Aziz
Published: June 2021

The synthesis of 1,8-ethanophthalazine derivatives from reaction of cyclopenta[ c]pyridazines with arylidenemalononitrile or active methylene nitriles is described.
A Remarkable Rate-accelerating Metal Ion Effect on the Intramolecular Transesterification Reaction of a Phosphodiester in Acetonitrile
Authors: Kondo Shin-ichi , Yoshida Kitaro , Yano Yumihiko
Published: June 2021

The intramolecular transesterification reaction of 2-hydroxypropyl 4-nitrophenyl phosphate is greatly accelerated (105–106 fold) by the addition of divalent metal ions such as Zn2+ and Cu2+ in MeCN without a base; the metal ion effect is quite sensitive to the content of H2O in MeCN.
Stereoselective Thallium-induced Ring Contraction of Glycals
Authors: Braithwaite Dana H. , Holzapfel Cedric W. , Williams D. Bradley G.
Published: June 2021

Various glycals, treated with TI(NO3)3 · 3H2O under mild conditions in an acetonitrile–methanol solvent mixture, underwent ring contraction in a stereoselective fashion, affording stable acetal products.
Comparison of Thermodynamic Hydrogen Bonding, Brönsted and Gas-phase Basicity with Spectroscopic Hydrogen Bonding Basicity of N1, N1-Dimethylformamidines. Similarities and Differences in Substituent Effects
Authors: Raczyńska Ewa D.
Published: June 2021

Comparison of the thermodynamic (log KHB with 4-fluorophenol in CCI4, p Ka in azeotropic ethanol and GB in the gas phase) with spectroscopic basicities (Δ v OH of methanol in CCI4) for N1, N1-dimethylformamidines shows good correlation only between the p Ka and Δ VOH values; no general simple linear model can be applied to the log K HB/Δ vOH and GB/Δ VOH relations.
Microwave-assisted Oxidation of Alcohols by Pyridinium Chlorochromate
Authors: Chakraborty Vaishali , Bordoloi Manobjyoti
Published: June 2021

An efficient and mild methodology for the oxidation of alcohols to the corresponding carbonyl functions is described using pyridinium chlorochromate under microwave irradiation.
Deoximation by Pyridinium Chlorochromate under Microwave Irradiation
Authors: Chakraborty Vaishali , Bordoloi Manobjyoti
Published: June 2021

Regeneration of carbonyl functions from oximes can be accomplished by use of pyridinium chlorochromate under microwave irradiation within a short time with excellent yields.
Microwave-promoted Trifluoroacetylation of Amines with TiO(CF3CO2)2
Authors: Iranpoor Nasser , Zeynizadeh Behzad
Published: June 2021

Conversion of amines to their corresponding trifluoroacetamides was performed with TiO(CF3CO2)2 in a conventional microwave oven under solvent-free conditions in excellent yields.
Selective Topochemical Photodimerization of Styryldicyanopyrazines in the Solid State
Authors: Kim Jae Hong , Matsuoka Masaru , Fukunishi Koushi
Published: June 2021

Selective topochemical photodimerization of styryldicyanopyrazines proceeded in the solid state, and their differences in molecular stacking evaluated by X-ray analysis controlled the reactivity and stereochemistry.
Facile Total Syntheses of Two Novel 4-Alkenyloxy-2,6-dihydroxyacetophenones
Authors: Huang Chusheng , Zhang Zhe , Li Shuhua , Li Yulin
Published: June 2021

Two novel acetophenones, 4-(1′-geranyloxy)-2,6-dihydroxyacetophenone 1 and 4-(1′-farnesyloxy)-2,6-dihydroxy-acetophenone 2 isolated from the fruit of Evodia merrillii and from the aerial parts of Borronia ramosa respectively, have been synthesized starting from 2,4,6-trihydroxyacetophenone 3; the key step in their total synthesis is the regioselective alkenylation onto the intermediate 6 with alkenyl bromide.
AM1 Study of [C,C]8Carbo- and [C,H]8Carbo-cyclooctatetraene and Smaller Carbomers
Authors: Yavari Issa , Jabbari Arash , Samadizadeh Marjaneh
Published: June 2021

The results of AM1 semi-empirical SCF MO calculations are reported for [C,C]8carbo-cyclooctatetraene, [C,H]8carbo-cyclooctatetraene and smaller carbomers, derived from benzene and cyclobutadiene.
Facile Total Synthesis of Isopregomisin
Authors: Mingyi Wang , Hongfang Yang , Anxin Wu , Xinfu Pan
Published: June 2021

Isopregomisin, a diarylbutane-lignan, has been synthesized by a short and efficient route starting from pyrogallol; the synthesis involves a novel selective demethylation reaction and the coupling reaction of the Grignard reagent produced from an aryl bromopropane with ( E)-2- tert-butyl-3-phenyloxaziridine.
Lanthanide Bis[bis(1,1,1,3,3,3-hexafluoro-2-propoxy)sulfonyl]amide as a Novel Effective Acylation Catalyst
Authors: Nie Jin , Zhao Zhongming , Xu Jun , Liu Dafan
Published: June 2021

Lanthanide complexes Ln(BHFPSA)3 {BHFPSA = N[SO2OCH(CF3)2]2} catalyse the acylation of alcohols or phenols under very mild conditions to afford esters in high yields.
Diastereoselective Synthesis of N-Substituted Ethyl 4-Phenyloxazolidine-2-carboxylates
Authors: Katritzky Alan R. , Cobo-Domingo Justo , Yang Baozhen , Steel Peter J.
Published: June 2021

( S)-2-Phenylglycinol, ethyl glyoxylate, formaldehyde and benzotriazole formed stereospecifically ethyl (2 S,4 S)- N-(benzotriazol-1-yl)methyl-4-phenyloxazolidine-2-carboxylate (1) which was converted into chiral N-substituted oxazolidines, via regiospecific substitutions of the benzotriazolyl residue.
Rearrangements in the 11-Thia-9,10-dihydro-9,10-ethanoanthracene Series. Synthesis of a Bridged Thienooxepin
Authors: Minassian Frédéric , Pelloux-Léon Nadia , Averbuch-Pouchot Marie-Thérèse , Vallée Yannick
Published: June 2021

A rearrangement from 11-thia-9,10-dihydro-9,10-ethanoanthracene derivatives into a thienooxepin is reported; the structure of the bridged oxepin is confirmed by X-ray analysis.
Regioselective Base-induced Condensations of Acrylic Acid Derivatives
Authors: Abdel-Ghani E.
Published: June 2021

The orientation of cyclization of the reaction of methyl aroylacrylate (1) and aroylacrylic acid (8) with ethyl acetoacetate and/or thiourea leading to the formation of 4-aroylmethylcyclopentane-1,3-dione (2) 5-aryl-3-oxocyclohexene-1,2-dicarboxylic acid (9), 2-imino-5-aroylmethylthiazolidin-4-one (11) and 6-aryl-2-sulfonylpyrimidine-4-carboxylic acid (14) depends on the medium employed; some compounds show moderate antiviral activities against tobacco necrosis virus.
Tautomerisation in 1-(4-Methylphenylazo)naphthalen-2-ol and 2-(4-Methylphenylazo)-4-methylphenol: A Crystallographic and 13C{1H}NMR Study
Authors: Cross Wendy I. , Flower Kevin R. , Pritchard Robin G.
Published: June 2021

The acetic acid esters of 1-(4-methylphenylazo)naphthalen-2-ol 1 and 2-(4-methylphenylazo)-4-methylphenol 3 are prepared and characterised by single crystal X-ray diffraction studies and 13C{1H}NMR spectroscopy; the position of the C(2)13C resonance for the ester is used to predict the position of resonant frequency of the equivalent carbon in the parent alcohols and hence, calculate the position of the azo-hydrazone equilibrium in these compounds.
A New Synthesis of 2-(2-Hydroxyalkyl)- and 2-(2-Aminoalkyl)-morpholines via 3-Morpholinones
Authors: Dobrev Alexander , Nechev Lubomir , Ivanov Christo , Bon Maryse
Published: June 2021

A new pathway for the synthesis of 2-(1-hydroxyalkyl)- and 2-(1-arylaminoalkyl)-morpholines via reaction of α-hydroxy- or α-amino-alkylation of 3-morpholinones followed by reduction with LiAIH4 of the intermediate compounds into the target substituted morpholines is proposed.
Synthesis of 2-O-Ethyl Analogues of 5′-Azido- and 5′-Amino-2’,5′-dideoxyuridines as New Antiviral Agents
Authors: Zeid Ibrahim F. , Abdel-Rahman Adel A.-H.
Published: June 2021

2- O-Ethyluracil derivatives 3a-d have been silylated with HMDS and condensed in the presence of TMS-triflate with a 5-azido sugar to give the corresponding β-nucleosides 5a-d and their α-anomers 6a-d; deprotection afforded 7 and 8, and the 5′-amino derivatives 9a,b could be obtained by treatment of the corresponding 5′-azido nucleosides with triphenylphosphine in pyridine.
Acid Dissociation and Dimerisation Constants of Some cis-Diaqua Complexes of Palladium(II) with Chelating N, N’ and N, C’ Ligands1
Authors: Wimmer Franz L. , Wimmer Smita , Afcharian Amenah , Castan Paule , Fabre Paul L.
Published: June 2021

The acidity and dimerisation constants are determined for [Pd(L)(H2O)2]2+ [L=2-(aminomethyl)pyridine and N′-methyl-2,4’ -bipyridin-3-ylium
The Stereochemistry of Epoxidation of Steroidal 4,6-Dienes
Authors: Hanson James R. , Hitchcock Peter B. , Kiran Ismail
Published: June 2021

The epoxidation of some androsta-4,6-dienes with m-chloroperbenzoic acid has been shown to give the 4β, 5β; 6α, 7α-diepoxides, the stereochemistry can be rationalized in terms of the directing effect of one epoxide on the facial selectivity of the second epoxidation.
Aluminium-mediated Reductive Dimerization of Aromatic Dialdehydes
Authors: Sahade Daniel A. , Kawaji Takatoshi , Sawada Tsuyoshi , Mataka Shuntaro , Thiemann Thies , Tsukinoki Takehito , Tashiro Masashi
Published: June 2021

Pinacol coupling reaction of several aromatic dialdehydes 1a-d using inexpensive aluminum powder as a reductive reagent in aqueous NaOH-methanol media afforded dimeric compounds 2a-d as main products, in which only one carbonyl group of 1 was reduced.
A Facile Synthesis of Stable Heterocyclic Phosphorus Ylides
Authors: Yavari Issa , Maghsoodlou Malek Taher , Djahaniani Hoorih , Hazeri Norollah
Published: June 2021

Stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine, dialkyl acetylenedicarboxylate and strong NH-acids, such as imidazole, benzimidazole, benzotriazole or carbazole.
Synthesis of Clusters containingTwo C2Co2 Cores
Authors: Chen Xue Nian , Zhang Jie , Ding Er-Run , Yin Yuan-Qi , Sun Jie
Published: June 2021

New clusters [Co2(CO)6]2μ-HC2RC2H) [R=C6H4(CO2CH2)2-1,2 2, CH2OCH2 3, (CH2)5 4] have been isolated from the reaction of Co2(CO)8 1 with diyne ligands HC=CRC=CH, and the structure of 2 has been established by single-crystal X-ray diffraction methods.
Hydrophobic Effects in 1,3-Dipolar Cycloaddition of C,N-Diphenylnitrone with Dibutyl fumarate in Aqueous Solutions
Authors: Gholami Mohammed R. , Yangjeh Aziz Habibi
Published: June 2021

The reaction rate of 1,3-dipolar cycloaddition of C,N-diphenylnitrone with dibutylfumarate increases dramatically in aqueous solutions relative to other solvents.
A Rapid and Convenient Synthesis of Oximes in Dry Media under Microwave Irradiation
Authors: Hajipour Abdol Reza , Mallakpour Shadpour E. , Imanzadeh Gholamhasan
Published: June 2021

In a novel method, the reaction of hydroxylamine hydrochloride with a number of aldehydes and ketones under microwave irradiation and solventless ‘dry’ condition gave oximes in excellent yield.
Efficient Solvent-free Oxidation of Benzylic and Aromatic Allylic Alcohols and Biaryl Acyloins by Manganese Dioxide and Barium Manganate
Authors: Firouzabadi Habib , Karimi Babak , Abbassi Mohammad
Published: June 2021

Active manganese dioxide and commercially available barium manganate are used for the efficient oxidation of benzylic and aromatic allylic alcohols and biaryl acyloins under solvent-free conditions.
Hydrolytic and Dinuclear Species Formed by Copper(II) with Di-, Tri- and Tetra-peptides Containing Proline in the Second Position
Authors: Chruscinska Elzbieta , Garribba Eugenio , Micera Giovanni , Sanna Daniele
Published: June 2021

A significant amount of hydrolysed species is formed by interaction of CuII with oligopeptides having proline in the second position; a dimetallic species is found in the CuII-Pro-Pro system.
Microwave-assisted Syntheses of 1,2-Diketones
Authors: Mitra Alok Kumar , De Aparna , Karchaudhuri Nilay
Published: June 2021

A comparative study of the conversion of a number of α-hydroxyketones into 1,2-diketones by three oxidants under microwave irradiation is reported.
Ruthenium-catalyzed Regioselective Synthesis of Dienol Diesters
Authors: Kabouche Ahmed , Kabouche Zahia , Bruneau Christian , Dixneuf Pierre Henri
Published: June 2021

(Geminal, geminal) dienol diesters are obtained in one step by direct addition of carboxylic acids to terminal diynes in the presence of ruthenium catalysts such as RuCI2(PR3)(arene) or [Ru(μ-O2CH)(CO)2(PR3)]2 while the catalyst [PPh2(CH2)4PPh2]Ru[η3-CH2=C(Me)CH2]2 favours the formation of regioselective ( Z,Z) dienol diesters.
The Formation and Structure of Some Androstane 4- and 6-Ketones
Authors: Flaih Nazar , Hanson James R. , Hitchcock Peter B. , Kiran Ismail
Published: June 2021

The preparation of some substituted androstane 4- and 6-ketones is described revealing further examples of neighbouring group participation between substituents at C-4 and C-6; the X-ray crystal structure of androstane-4,6,17-trione showed that it existed in a form that was a hybrid of the Δ4- and Δ6-enolates.
A Practical and Efficient Procedure for Preparation of Diacetals from 2,2-Bis(hydroxymethyl)propane-1,3-diol with Aldehydes and Ketones Catalysed by Anhydrous Ferrous Sulfate
Authors: Jin Tong-Shou , Ma Yan-Ran , Li Tong-Shuang , Wang Jian-Xin
Published: June 2021

Synthesis of diacetals in excellent yields from aldehydes and ketones with 2,2-bis(hydroxymethyl)propane-1,3-diol is carried out in refluxing benzene or toluene with anhydrous ferrous sulfate as catalyst.
Regioselective Benzylation of an Indazolyl-substituted Pyrazole under the Influence of Inorganic Solid Supported Bases
Authors: Branco M. W. , Cao R. Z. , Liu L. Z. , Ege G.
Published: June 2021

The benzylation of an indazolyl-substituted pyrazole under the influence of KOH–AI2O3, KF–AI2O3 and CsF–AI2O3 is investigated.
A Novel Synthesis of Allyl Sulfides and Allyl Selenides via Sm–BiCl3 System in Aqueous Media
Authors: Zhan Zhuangping , Lu Genliang , Zhang Yongmin
Published: June 2021

Allyl sulfides and allyl selenides are synthesized via the reaction of allyl bromide with disulfides and diselenides promoted by the Sm–BiCl3 system in aqueous media in moderate to good yields.
Complexation Thermodynamics of Selenacrown Ether: Origin of High Silver(I) Selectivity of 1,5,14,18-Tetraselena-8,11,21,24-tetraoxacyclohexacosane
Authors: Liu Yu , Dong Shu-Ping , Inoue Yoshihisa , Wada Takehiko
Published: June 2021

The thermodynamic parameters and relative cation selectivity for complexation of some alkali and heavy metal cations with 1,5,14,18-tetraselena-8,11,21,24-tetraoxacyclohexacosane (selena-26-crown-8) are investigated for the first time by titration calorimetry in water–acetonitrile (1:24 v/v) at 25 °C to show the contrasting complexation thermodynamic behaviour between Ag+ and alkali or Tl+ and a very high Ag+ selectivity, originating from the exclusive contribution of the enthalpy term probably owing to the partially covalent interaction between Ag+ and Se donor.
Tin Chloride Catalysed Oxidation of Acetone with Hydrogen Peroxide to Tetrameric Acetone Peroxide
Authors: Jiang Heng , Chu Gang , Gong Hong , Qiao Qingdong
Published: June 2021

SnCl4·5H2O and SnCl2·2H2O are efficient catalysts for the oxidation of acetone with 30% hydrogen peroxide at room temperature and produce tetrameric acetone peroxide which is identified by molecular weight determination, elemental analysis, FTIR, NMR and MS.
A New Preparation of Perdeuterated Ferrocene
Authors: Shabanova Elizabeth , Schaumburg Kjeld , Kamounah Fadhil S.
Published: June 2021

A new synthesis of ferrocene- d10 using acid catalysed exchange is described.
A Hypervalent Phosphorane-Palladium Cation Complex Bearing Benzaldehyde
Authors: Toyota Koichiro , Yamamoto Yohsuke , Akiba Kin-ya
Published: June 2021

[Rf2PPd(PhCHO)(Ph2PCH2CH2PPh2)] + SbF6-[Rf = o-C6H4C(CF3)20] 5 is prepared by the reaction of Rf2PPdCI(Ph2PCH2CH2PPh2) 1 with AgSbF6 in the presence of benzaldehyde in 92% yield, and the structure determined by X-ray diffraction analysis.
Microwave-assisted Synthesis of Triazones and 4-Oxo-oxadiazinane in Dry Media
Authors: Balalaie Saeed , Hashtroudi Mehri S. , Sharifi Ali
Published: June 2021

Three component condensation of N,N-dimethylurea, paraformaldehyde and primary amines using montmorillonite K-10 in dry media under microwave irradiation leads to triazones 5a-f in high yields.
Demethylation of Methyl Aryl Ethers using Pyridine Hydrochloride in Solvent-free Conditions under Microwave Irradiation
Authors: Kulkarni P. P. , Kadam A. J. , Mane R. B. , Desai Uday V. , Wadgaonkar P. P.
Published: June 2021

Methyl aryl ethers are deprotected in high yields using pyridine hydrochloride in the absence of solvent under microwave irradiation
A Facile Synthesis of 3-Cyclopropyl- and 5-Cyclopropyl-isoxazoles
Authors: Singh Okram Mukherjee , Junjappa H. , Ila H.
Published: June 2021

The regioselective synthesis of isomeric isoxazoles 3-(2-arylcyclopropyl)-5-methylthio- and 5-(2-arylcyclopropyl)-3-methylthio-isoxazoles is described.
A Selective Catalytic Method of Enol-acetylation under Microwave Irradiation
Authors: Kalita Dipok J. , Borah Ruli , Sarma Jadab C.
Published: June 2021

Six-membered cyclic ketones on treatment with acetic anhydride and a catalytic amount of iodine under microwave irradiation give the corresponding enol acetates in good yield.
Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Aluminium in Hydrochloric Acid and Sodium Hydroxide Solutions
Authors: Madkour Loutfy H. , Issa R. M. , El-Ghrabawy I. M.
Published: June 2021

This investigation is designed to apply an advanced kinetic–thermodynamic model on the data obtained from acidic and alkaline corrosion of aluminium using bis- and mono-azo dyes as corrosion inhibitors.
New Insights on the Reaction of 2-Aminothiazole with Ethyl Bromopyruvate for the Synthesis of 6-Ethoxycarbonylimidazothiazole. Crystal Structure of 5-Acetyl-6-ethoxycarbonylimidazo-[2,1-b]thiazole and 2-Ethoxycarbonyl-2-hydroxy-7-oxo-thiazole[2,3-b]pyrimido[2,3-d]furan
Authors: Canestrari Stefania , Sgarabotto Paolo , Andreani Aldo , Greci Lucedio
Published: June 2021

The reaction of 2-aminothiazole 1c with ethylbromopyruvate yields two by-products 4 and 5.
Direct Synthesis of Imides from Dicarboxylic Acids using Microwaves
Authors: Seijas Julio A. , Vázquez-Tato M. Pilar , Martínez M. Montserrat , Núñez-Corredoira Gonzalo
Published: June 2021

1,4- and 1,5-dicarboxylic acids, when treated with amines in a domestic microwave oven, afford good yields of the corresponding imides.
Regioselective Addition of Grignard Reagents to Isoxazole-4,5-dicarboxylate Esters
Authors: Batchelor Kevin J. , Bowman W. Russell , Davies Roy V. , Hockley Michael H. , Wilkins David J.
Published: June 2021

Regioselective mono-addition of a range of Grignard reagents with the 5-esters of 3-methylisoxazole-4,5-diesters affords 5-keto derivatives instead of tertiary alcohols which is explained by the complexing ability of the isoxazole oxygen atom and by the electron withdrawing effect of the isoxazole ring.
Synthesis of 2,3,4,6-Tetrasubstituted Pyridines as Precursors to Bicycles and Polycycles
Authors: Abu-Shanab Fathi A.
Published: June 2021

Ammonium 1,1,3-tricyano-2-methylprop-2-enide 1a and sodium 2-amino-1,1,3-tricyanoprop-2-enide 1b are treated with H2S in absolute ethanol to afford 3,4,6-trisubstituted pyridine-2(1 H)-thione 3a,b; their structures are confirmed by reaction with phenacyl bromide to give 4a,b; also 3a,b reacts with DMFDMA to give 6a,b, and on treatment of 6a with phenacyl bromide affords 8; reaction of 4b with DMFDMA gave 9 while methylation of 3a,b by methyl iodide in ethanolic sodium hydroxide gives 10a,b.
Homocoupling of Substituted Benzenes to Symmetrical Biaryls with Mercury(II) in the Presence of Cerium(IV)
Authors: Iranpoor Nasser , Shekarriz Marzieh
Published: June 2021

Homocoupling of substituted benzenes to symmetrical biaryls is achieved with different cerium(IV) compounds such as cerium(IV) triethylammonium nitrate (CTEAN), cerium(IV) pyridinium nitrate (CPN) and Ce(OTf)4 in the presence of HgII in good to high yields.
Dehydration of Aldoximes to Nitriles Using a Polymeric Reagent
Authors: Tamami B. , Kiasat A. R.
Published: June 2021

Aldoximes undergo rapid dehydration with polyvinylpyrrolidone–thionyl chloride complex under mild reaction conditions to afford nitriles in high yields
Palladium-catalysed Heteroannulation with Acetylenic Carbinols: Synthesis of 3-Acylmethylisoindolin-1-ones
Authors: Kundu Nitya G. , Khan M. Wahab , Mahanty Jyan S.
Published: June 2021

Palladium-catalysed reactions of 2-iodobenzamides 1–6 with acetylenic carbinols 7–12 having a terminal acetylenic group and an adjacent carbinol functionality result in the formation of the 3-acylmethylisoindolin-1-ones 13–23 in one step.
Studies on 5-Bromo-4,7-dimethylindene, an Intermediate in the Synthesis of 6-Bromo-5,8-dimethylisoquinoline
Authors: Raposo M. Manuela M. , Pereira Alexandra M. B. , Oliveira-Campos Ana M. F. , Shannon Patrick V. R.
Published: June 2021

We report the complete characterisation of all the precursors of 6-bromo-5,8-dimethylisoquinoline via the synthesis of Miller and Moock, and the synthesis of 6-bromo-4,7-dimethyl-2-(5′-Bromo-4’,7′-dimethyl)-2’,3′-dihydro-1' H-inden-1′-yl)-1 H-indene.
Synthesis of RGD Analogues Containing α-Trifluoromethylaspartic Acid as Potential Fibrinogen Receptor Antagonists
Authors: Pozzo Alma Dal , Dikovskaya Klara , Moroni Maurizio , Fagnoni Maurizio , Vanini Laura , Bergonzi Roberto , de Castiglione Roberto , Bravo Pierfrancesco , Zanda Matteo
Published: June 2021

The total synthesis of a peptide containing α-trifluoromethylaspartic acid at the P3 position is described.
Cycloaddition of Ketene Acetals with 4-Bromo-6-spiroepoxycyclohexa-2,4-dienone
Authors: Mondon Martine , Boeker Norbert , Gesson Jean-Pierre
Published: June 2021

4-Bromo-6-spiroepoxycyclohexa-2,4-dienone reacts as a diene in an inverse electron-demand reaction with 1-ethoxy-3-methoxy-1-trimethylsilyloxybuta-1,3-diene but as a dienophile with 1-ethoxy-3-methylene-4-(ethoxy trimethylsilyloxymethylene)-1-cyclohexene.
A Novel Route to Stereoselective Synthesis of (4R,5S)-O-Acetylosmundalactone and (4S,5R)-O-Acetylosmundalactone
Authors: Yonghong Gan , Fangning Zhang , Xinfu Pan
Published: June 2021

A route has been developed for the enantioselective synthesis of (4 R,5 S)- O-acetylosmundalactone 1 and (4 S,5 R)- O-acetylosmundalactone 2 by using Sharpless kinetic resolution of the racemic 1-(2-furyl)ethanol 6 as a key step.
Synthesis of Phospholipids Bearing a Conjugated Oxo-polyunsaturated Fatty Acid Residue
Authors: Zhu Changjin , Ohashi Takaaki , Morimoto Tatsuya , Onyango Arnold N. , Takao Kaneko , Shimizu Sakayu , Nakajima Shuhei , Baba Naomichi
Published: June 2021

2-(15′-Oxo-5’,8’,11’,13′-eicosatetraenoyl)-1-stearoyl- sn-glycerol(3)phosphocholine (APC-CO) 1 and 2 and 2-(13′-oxo-9’,11′-octadecadienoyl)-1-stearoyl- sn-glycero(3)phosphocholine (LPC-CO) 3 are synthesized and an analytical system established for the determination of geometrical isomers at the 13’ position of APC-CO.
Stereoselective Synthesis of Tetraalkyl Cyclobutene-1,2,3,4-tetracarboxylates. Synthesis of Tetraalkyl (Z,Z)-Buta-1,3-diene-1,2,3,4-tetracarboxylates
Authors: Yavari Issa , Nourmohammadian Farahnaz
Published: June 2021

Tetraalkyl cyclobutene-1,2,3,4-tetracarboxylates, prepared by intramolecular Wittig reaction between a vinylphosphonium salt and diethyl 2-oxobutanedioate, undergo electrocyclic ring-opening reactions, in boiling toluene, to produce highly electron-deficient 1,3-dienes.
Coupling of Geminal Dihalides with Disodium Tetracarbonyl Ferrate: A Novel Reactivity Pattern for Collman's Reagent
Authors: Warner Kirstin F. , Rehman Atiq-ur , Jha Salil K. , Schnatter Wayne F. K.
Published: June 2021

The reaction of gem-dihalides with Na2Fe(CO)4 results in the formation of alkenes instead of the iron(O) carbene complexes.