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Carboxylic Acids, Carboxylic Acid Derivatives, and Acyl Substitution Reactions
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
An acid halide has a halogen, usually chlorine or bromine, attached directly to a carbonyl (X—C=O). What is an acid chloride?
2-(4-Biphenylyl)-1,3,4-oxadiazoles: synthesis and mesogenic studies
Published in Liquid Crystals, 2018
Farid Fouad, David R. Davis, Robert Twieg
As an alternative preparative route (not shown), the same monobenzoyl hydrazine can be reacted instead with an aliphatic acid anhydride (or acyl halide) to give the unsymmetrical monobenzoyl monoacyl hydrazine. This intermediate can then in turn be dehydrated to give the 1,3,5-oxadiazole with a variety of agents, including polyphosphoric acid (PPA) and phosphorous oxychloride (POCl3) [46,47]. In a complimentary route to 1,3,4-oxadiazoles also seen in Scheme 1 starting from a substituted benzonitrile, the 1,2,3,4-tetrazole derivative is readily prepared by reaction with sodium azide [48–50]. The tetrazole, in turn, is acylated and this derivative (not shown) loses nitrogen and rearranges to the desired 1,3,4-oxadiazole [51–53]. This overall process is the Huisgen 1,3,4-oxadiazole synthesis. The tetrazole acylation can be performed with an acid chloride or acid anhydride (including an acid anhydride generated from the respective carboxylic acid in situ with dicyclohexylcarbodiimide) [54].
An insight on the different synthetic routes for the facile synthesis of O/S-donor carbamide/thiocarbamide analogs and their miscellaneous pharmacodynamic applications
Published in Journal of Sulfur Chemistry, 2023
Faiza Asghar, Bushra Shakoor, Babar Murtaza, Ian S. Butler
Kumavat et al. [72] prepared a mixture containing aliphatic amines, CS2, and Et3N in 1 mL water that was agitated for 5 min at room temperature. Dropwise additions of acyl halide were made, and the reaction mixture was stirred for 20 min until the reaction was completed. The solids were collected, washed in ethanol/methanol or diethyl ether, and dried in the open air. Ethyl acetate was added to the filterate and the organic layer was separated and dried over Na2SO4 (Scheme 35). In most instances, high-purity reaction products were produced, and in a few cases, the products were refined using silica gel column chromatography with petroleum ether-ethyl acetate to yield analytically pure compounds.