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A DMAP (4-dimethylaminopyridine) catalyzed cyclization of methyl 2-alkynylbenzimidates has been developed, which affords 3-methoxy-1-methyleneisoindoles with excellent Z-stereoselectivity under mild and transition-metal-free conditions. The (Z)-3-methoxy-1-methyleneisoindole products can be converted to corresponding 3-amino-1-methyleneisoindoles, 3-methoxy-isoindoles, 3-methyleneisoindolinones and isoindolinones with high efficiency. 相似文献
44.
Zong Chang Feng Liu Liang Wang Mengying Deng Chunhua Zhou Qinchao Sun Jun Chu 《中国化学快报》2019,30(10):1856-1882
Taking the advantage of reduced scattering and low autofluorescence background, the NIR fluorescence probes, such as fluorescence proteins, organic molecules and nanoparticles, not only hold the promise of in vivo imaging of biological processes in physiology and pathology with high signal-to-noise ratio, but also for clinical diagnosis. In this review, we provide an overview of the recent progress on NIR probes, focusing on fundamental mechanisms of NIR dyes and nanoparticles, and protein engineering strategies for NIR proteins. 相似文献
45.
This study evaluated the performance of in-vitro freehand aspiration of a simulated cyst with ultrasound aspiration guided by a newly designed laser assisted (LA) device. The LA device was equipped with an adjustable light source generating a sector light plane. This laser light plane was parallel to and overlapped the ultrasound acoustical plane, to help with needle positioning. Five operators randomly performed 30 freehand or LA ultrasound guided aspirations of a simulated cyst. The frequency was set at 8 MHz and depth at 4 cm. Procedure time and number of syringe withdrawals were statistically compared before and after using the LA device. Both experienced and inexperienced operators required significantly less time to perform the aspiration and had fewer syringe withdrawals when using the LA device. The LA device provides a reference plane in space, allowing the operator to more accurately position and adjust needle direction. Additional in-vivo testing is required to test the clinical practicability. 相似文献
46.
Yong Zhang Yonghai Liu Shuai Zhang Lei Shi Wei Wang Hao Li 《Tetrahedron letters》2019,60(22):1463-1466
An acid-promoted 2-component Mannich annulation reaction of readily available acetylbenzaldehydes and secondary amines has been reported. The approach provides a simple and efficient method under mild conditions to synthesize 3-aminoindan-1-one derivatives in moderate to good yields. 相似文献
47.
Deep levels in LPE GaAs were studied in relation to growth conditions. The residual deep levels in LPE layers are hole traps 0.50 and 0.65 eV above the top of the valence band. Their concentrations are of the order of 1013 cm-3 for growth temperatures between 650 and 840°C, and increase with increasing growth temperature. The activation energy of incorporation is about 0.7 eV, which is very close to that of an arsenic vacancy. It is also noted that their concentrations near the grown surface are independent of the growth temperature. This indicates that the hole traps undergo an annealing effect after the growth period. From the experimental results for Fe and oxygen doping, each impurity acts as a deep level only when it makes a complex defect with a gallium vacancy, otherwise they are shallow levels, The distribution coefficients at 750°C are 1 × 10-7 and 1.1 × 10-5 for the deep and Fe and the shallow acceptor, respectively. 相似文献
48.
Pingping Li Jian Sun Xiaohe Xu Zhisheng Mi Yuyan Lin Jingya Cheng Renren Bai Yuanyuan Xie 《Tetrahedron letters》2018,59(27):2640-2643
A ferric nitrate-promoted cross-dehydrogenative coupling reaction of N-hydroxyphthalimide (NHPI) with toluene derivatives is reported. The reaction proceeded smoothly using molecular oxygen as an oxidant, providing an efficient method for the synthesis of N-hydroxyimide esters. Furthermore, a plausible mechanism was proposed. 相似文献
49.
Aileen M. Eagleton Emma K. Ambrogi Sophia A. Miller Dr. Nataliia Vereshchuk Prof. Katherine A. Mirica 《Angewandte Chemie (International ed. in English)》2023,62(49):e202309078
Owing to high modularity and synthetic tunability, metal–organic frameworks (MOFs) on textiles are poised to contribute to the development of state-of-the-art wearable systems with multifunctional performance. While these composite materials have demonstrated promising functions in sensing, filtration, detoxification, and biomedicine, their applicability in multifunctional systems is only beginning to materialize. This review highlights the multifunctionality and versatility of MOF-integrated textile systems. It summarizes the operational goals of MOF@textile composites, encompassing sensing, filtration, detoxification, drug delivery, UV protection, and photocatalysis. Building upon these recent advances, this review concludes with an outlook on emerging opportunities for the diverse applications of MOF@textile systems in the realm of smart wearables. 相似文献
50.
明确了“物质分类”“氧化还原反应”“电离与离子反应”等概念对物质性质的认识功能,阐述了鲁科版教材通过构建认识模型,基于认识发展布局学习素材,依据学习理解、应用实践、迁移创新构建进阶的评价体系等方式促进核心知识向能力、素养转化的编写思路,并提出了使用建议。 相似文献