The benzylic functionalization of alkylpyridines is an important pathway for pyridine derivatives synthesis. The reaction partners, however, were mostly limited to highly reactive polar electrophiles. Herein, we report a potassium amide-catalyzed selective benzylic C-H bond addition of alkylpyridines to styrenes. Potassium bis(trimethylsilyl)amide (KHMDS), a readily available Brønsted base, showed excellent catalytic activity and chemoselectivity. A series of alkylpyridine derivatives, including benzylic quaternary carbon substituted pyridines, were obtained in good to high yield. Preliminary mechanistic studies revealed that the deprotonation equilibrium is probably responsible for the excellent selectivity.
Direct functionalization of the benzylic C-H bond of diarylmethanes is an important strategy for the synthesis of diarylmethine-containing compounds. However, the methods developed to date for this purpose require a stoichiometric amount (usually more) of either a strong base or an oxidant. Reported here is the first catalytic benzylic C-H bond addition of diarylmethanes to styrenes and conjugated dienes. A potassium zincate complex, generated from potassium benzyl and zinc amide, acts as a catalyst and displays good activity and chemoselectivity. Considering the atom economy of the reaction and the ready availability of the catalyst, this reaction constitutes a practical, efficient method for diarylalkane synthesis.
Background Each rare disease only affects a small number of population. However, a total of 7000 rare diseases may affect 10% of the population. Due to the severity and lack of rare disease awareness, rare disease represents a huge challenge for the healthcare system. In Western countries, patient organizations have been playing an integral role in raising awareness, advocating legislation, and supporting drug development. This study aims to assess the unmet needs of rare disease patient organizations in China, and identify their unmet needs, providing essential information for the government and legislators. Results A total of 28 individuals representing 28 patient organizations in China were interviewed. Most organizations do not have official registration, employees, written standard operation protocol, or reliable financial resources. Misdiagnosis or delayed diagnosis is common, and treatment is often lacking. Due to the lack of financial resources, no organizations have been able to sponsor academic research, unlike their counterparts in Western countries. As to challenges, 71.4% of interviewees listed lack of rare disease awareness among the general public, while 67.9% selected lack of financial resources. Further, only 7.3% of these organizations received support from the government, and 28.6% received support from the general public. As to recommendations to the government, 82.1% of interviewees selected special insurance programs for rare diseases because rare diseases have been generally excluded from the national medical insurance programs. In addition, 78.6% of interviewees recommended to stimulate rare disease research, 75% recommended to import orphan drugs, and 71.4% recommended legislation of an orphan drug act, highlighting the urgent need of therapies. Conclusions Due to lack of support and rare disease awareness, patient organizations in China are still in the early phase. To empower these patient organizations, the interviewees’ recommendations, including legislating orphan drug act and releasing official definition of rare diseases, should be considered by the government and legislators.
Developing metal–organic frameworks (MOFs) as heterogeneous catalysts attracts much attention because their high internal surface areas and open metal sites may facilely improve the catalytic activity. In this study, a copper-cluster-based MOF, denoted as {2Cu(L)(A)·3H2O} n (1, L = bis(4-(4H-1,2,4-triazol-4-yl)phenyl)methane, A = deprotonated 1,4-naphthalenedicarboxylic acid), has been constructed. 1 has a (3,10)-connected three-dimensional (3D) porous network structure with a new topology of {48·624·83}{43}2. Structural analysis reveals that copper ions adopt two coordination modes in the secondary building unit, forming polyhedral copper clusters by Cu–O–Cu bridge bonds. Detailed studies show that 1 can be employed as an efficient heterogeneous catalyst for converting CO2 to cyclic carbonates in 81.0–99.0% yield under 1 atm CO2 and solvent-free conditions. Furthermore, 1 retains good catalytic efficiency after 10 cycles (83.0% conversion). Moreover, 1 exhibits good catalytic performance toward azide–alkyne cycloaddition (AAC) reactions in an aqueous solution with the addition of sodium ascorbate, yielding a series of 1,4-disubstituted 1,2,3-triazoles in high yields (over 99.0%) and presenting recyclable ability.
Breaking saline KH: The combined KH/alkaline-earth metal amide catalysts display much better catalytic activity than their components in the hydrogenation of alkenes, suggesting the degradation and activation of saline KH with the metal amides.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.