Over the past decade, significant progress has been made in the direct C-H acylation of naphthalenes, occurring at the α or β-positions to yield valuable ketones through Friedel-Crafts acylation or transition-metal-catalysed carbonylative coupling reactions. Nevertheless, highly regioselective acylation of naphthalenes remains a formidable challenge. Herein, we developed a nickel-catalysed reductive ring-opening reaction of 7-oxabenzonorbornadienes with acyl chlorides as the electrophilic coupling partner, providing a new method for the exclusive preparation of β-acyl naphthalenes.
View Article and Find Full Text PDFHerein we reported a directing-group assisted strategy for nickel-catalysed reductive defluorinative sulfenylation of trifluoropropionic acid derivatives with disulfides in the presence of Zn, involving triple C-F bond cleavage. This process yielded a diverse array of carbonyl-sulfide di-substituted alkenes in moderate to good yields with good functional group tolerance. Specifically, the reactions exhibited high -selectivity with / ratio up to >99 : 1.
View Article and Find Full Text PDFChem Commun (Camb)
December 2022
Herein we reported the use of Earth-abundant iron as the catalytic metal in the presence of Mn to induce difluorobromoacetates to form carbon radicals, which reacted with trifluoromethyl olefins followed by β-F elimination to generate the corresponding -difluoroolefins. The cross-electrophile coupling displayed excellent functional group tolerance and broad substrate scope under mild reductive conditions, affording a large number of polyfluorinated compounds, which could be further transformed to other valuable molecules.
View Article and Find Full Text PDFHigh-pressure ultrasound-assisted extraction was used to extract polysaccharides from the Ligusticum chuanxiong rhizomes. Three independent variables, namely, extraction temperature (X1), ultrasonic power (X2) and extraction time (X3) were investigated. Response surface methodology was performed based on the results of single-factor tests.
View Article and Find Full Text PDFThe effects of acute and subacute toxicity of 1,8-cineole in Kunming mice were studied. After acute oral administration, the LD50 value (95% CL) was 3849 mg/kg (3488.8~4247.
View Article and Find Full Text PDFHigh-pressure ultrasound-assisted extraction technology was applied to extract ferulic acid, senkyunolide I, senkyunolide H, senkyunolide A, ligustilide and levistolide A from Ligusticum chuanxiong rhizomes. Seven independent variables, including solvent type, pressure, particle size, liquid-to-solid ratio, extraction temperature, ultrasound power, and extraction time were examined. Response Surface Methodology (RSM) using a Central Composite Design (CCD) was employed to optimize the experimental conditions (extraction temperature, ultrasonic power, and extraction time) on the basis of the results of single factor tests for the extraction of these six major components in L.
View Article and Find Full Text PDFXiang-Qi-Tang (XQT) is a Chinese herbal formula containing Cyperus rotundus, Astragalus membranaceus and Andrographis paniculata. Alpha-Cyperone (CYP), astragaloside IV (AS-IV) and andrographolide (AND) are the three major active components in this formula. XQT may modulate the inflammatory or coagulant responses.
View Article and Find Full Text PDFThe preparation of neem oil microemulsion and its acaricidal activity in vitro was developed in this study. In these systems, the mixture of Tween-80 and the sodium dodecyl benzene sulfonate (SDBS) (4:1, by weight) was used as compound surfactant; the mixture of compound surfactant and hexyl alcohol (4:1, by weight) was used as emulsifier system; the mixture of neem oil, emulsifier system and water (1:3.5:5.
View Article and Find Full Text PDFZhongguo Zhong Yao Za Zhi
August 2008
A field trial was carried out to study the influence of different kinds of spring topdressing on growth, yield and quality of Ligusticum chuanxiong. The results showed that the spring topdressing had effects of improving root length, tiller numbers and plant height to some extent. At the same time the chlorophyll content and dry weight accumulation especially the dry weight of root increased significantly.
View Article and Find Full Text PDFAjuga decumbens Thunb. is superficially similar to Prunella vulgaris Linn. and has been used as a substitution of the latter for along time.
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