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The dehydrogenation adjacent to an electron-withdrawing group provides an efficient access to α,β-unsaturated compounds that serving as versatile synthons in organic chemistry. However, the α,β-desaturation of aliphatic imines has hitherto proven to be challenging due to easy hydrolysis and preferential dimerization. Herein, by employing a pre-fluorination and palladium-catalyzed dehydrogenation reaction sequence, the abundant simple aliphatic amides are amendable to the rapid construction of complex molecular architectures to produce α,β-unsaturated imines. Mechanistic investigations reveal a Pd(0)/Pd(II) catalytic cycle involving oxidative H–F elimination of N-fluoroamide followed by a smooth α,β-desaturation of the in-situ generated aliphatic imine intermediate. This protocol exhibits excellent functional group tolerance, and even the carbonyl groups are compatible without any competing dehydrogenation, allowing for late-stage functionalization of complex bioactive molecules. The synthetic utility of this transformation has been further demonstrated by a diversity-oriented derivatization and a concise formal synthesis of (±)-alloyohimbane. α,β-unsaturated compounds serve as versatile synthons in organic chemistry, but the α,β-desaturation of aliphatic imines is challenging due to easy hydrolysis and preferential dimerization. Herein, the authors report the synthesis of α,β-unsaturated imines by employing a pre-fluorination and palladium-catalyzed dehydrogenation reaction sequence. [ABSTRACT FROM AUTHOR]

Introduction: This study was to investigate the correlations between pyrethroid exposure and bone mineral density (BMD) and osteopenia. Materials and methods: This cross-sectional study included 1389 participants over 50 years of age drawn from the 2007–2010 and 2013–2014 National Health and Nutrition Examination Survey (NHANES). Three pyrethroid metabolites, 3-phenoxybenzoic acid (3-PBA), trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropane-1-carboxylic acid (trans-DCCA), and 4-fluoro-3-phenoxybenzoic acid (4-F-3PBA) were used as indicators of pyrethroid exposure. Low BMD was defined as T-score < − 1.0, including osteopenia. Weighted multivariable linear regression analysis or logistic regression analysis was utilized to evaluate the correlation between pyrethroid exposure and BMD and low BMD. Bayesian kernel machine regression (BKMR) model was utilized to analyze the correlation between pyrethroids mixed exposure and low BMD. Results: There were 648 (48.41%) patients with low BMD. In individual pyrethroid metabolite analysis, both tertile 2 and tertile 3 of trans-DCCA were negatively related to total femur, femur neck, and total spine BMD [coefficient (β) = − 0.041 to − 0.028; all P < 0.05]. Both tertile 2 and tertile 3 of 4-F-3PBA were negatively related to total femur BMD (P < 0.05). Only tertile 2 [odds ratio (OR) = 1.63; 95% CI = 1.07, 2.48] and tertile 3 (OR = 1.65; 95% CI = 1.10, 2.50) of trans-DCCA was correlated with an increased risk of low BMD. The BKMR analysis indicated that there was a positive tendency between mixed pyrethroids exposure and low BMD. Conclusion: In conclusion, pyrethroids exposure was negatively correlated with BMD levels, and the associations of pyrethroids with BMD and low BMD varied by specific pyrethroids, pyrethroid concentrations, and bone sites. [ABSTRACT FROM AUTHOR]

This paper uses Chinese provincial data from 2006 to 2021 as a sample period to study the relationship between higher education development, industrial structure adjustment, and environmental pollution. Conclusions were as follows: (1) the industry structure adjustment can reduce environmental pollution in Chinese regions except eastern, and the increase in the proportion of the tertiary industry will increase pollution emissions in the eastern region. (2) Although there is a negative correlation between higher education and environmental pollution in China, it is not significant. From different regions, the coefficients in the eastern are positive which means aggravated environmental pollution, and the coefficients in the central region are not significant, but higher education in the western region improves environmental pollution. (3) Urbanization has a significant moderating effect on the national and regional environmental pollution, but in the central and western regions, it is smaller than the eastern region; although environmental regulation has a certain inhibitory effect on environmental pollution, the coefficient in the eastern region is significantly positive, and there is a situation of "more pollution, more control." Further, the increase of foreign direct investment will aggravate environmental pollution; although the elasticity coefficient in the eastern region is negative, there is a trend of improving environmental pollution, but it is not significant. The study holds promising implications for the development of policies related to education, industry, and the environment. Through the research on the relationship between the three, exploring and improving the regional environmental pollution level from the perspective of higher education and industrial structure have important practical significance for the regional green development. [ABSTRACT FROM AUTHOR]

Green finance is the main way to solve financing problems and support green technology innovation. The development of higher education is the source of innovative human capital and a key factor in promoting green economic growth. Studying the relationship between the three is an important realistic meaning for achieving green economic growth. Based on the idea of system coupling, this paper adopts the analysis method of the three-system coupling coordination model. This paper constructs a three-system coupling model, which incorporates green finance, higher education, and green economic growth into a unified framework, and based on a comprehensive review of the interaction and mechanism, the degree of system coupling is analyzed from the regional and provincial levels. Conclusions of the study are as follows: (1) the composite indexes of green finance, higher education, and green economic growth are all on the rise. The highest increase has been found in the index of higher education. In addition, the green finance index has also shown an accelerated upward trend in recent years, and green economic growth index has also shown a steady rise in recent years. (2) The upward trend of the coupling degree is relatively observable, but the overall coupling degree is still at low level. The coupling state has jumped from the low-degree coupling stage to the primary coupling stage, and the coupling degrees of the three major regions all show a fluctuating rising trends, but there are apparent regional differences. The degree of coupling between the eastern region and the other two regions is quite different. (3) During the sample period, the degree of coordination between green finance, higher education, and green economic growth in each province has increased to varying degrees. The degree of coordination in the eastern region is the best, the western region is the worst, and the central region is somewhere in between. The study concludes with implications for the protection of the environment. Finally, based on the empirical analysis results, this paper puts forward corresponding countermeasures and suggestions from the perspectives of improving the ability of green technology innovation, promoting the development of green finance and the high-quality development of higher education, and hoping to provide theoretical reference for the coordinated development of China's regional economy. [ABSTRACT FROM AUTHOR]

Key message: Two 2-phenylethanol biosynthetic pathways were constructed into Arabidopsis ; 2-phenylethanol biosynthesis led to reduced rate of lignin biosynthesis and increased cellulose-to-glucose conversion in the transgenic plants. Abstract: Lignin is the second most abundant biopolymer on the planet with importance for various agro-industrial activities. The presence of lignin in cell walls, however, impedes biofuel production from lignocellulosic biomass. The phenylpropanoid pathway is responsible for the biosynthesis of lignin and other phenolic metabolites such as 2-phenylethanol. As one of the most used fragrance chemicals, 2-phenylethanol is synthesized in plants from l-phenylalanine which is the first specific intermediate towards lignin biosynthesis. Thus, it is interesting to prove the concept that the phenylpropanoid pathway can be modulated for reduction of lignin as well as production of natural value-added compounds. Here we conferred two 2-phenylethanol biosynthetic pathways constructed from plants and Saccharomyces cerevisiae into Arabidopsis. As anticipated, 2-phenylethanol was accumulated in transgenic plants. Moreover, the transformants showed 12-14 % reduction in lignin content and 9-13 % increase in cellulose content. Consequently, the glucose yield from cell wall hydrolysis was increased from 37.4 % in wild type to 49.9-52.1 % in transgenic plants with hot water pretreatment. The transgenic plants had normal development and even enhanced growth relative to the wild type. Our results indicate that the shunt of l-phenylalanine flux to the artificially constructed 2-phenylethanol biosynthetic pathway most likely reduced the rate of lignin biosynthesis in Arabidopsis. [ABSTRACT FROM AUTHOR]