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An efficient, one-pot, protecting-group-free, and regioselective protocol to obtain enantiomerically pure (Z)-5-methylene-containing morpholin-2-ones, using α-amino acids and 5-bromo-4-methoxy enones as selective starting materials, is reported. The reaction was fully selective in providing the (Z)- regioisomer in all cases, regardless of the α-amino acid used; however, when a secondary amino group was used, only the (E)-isomer was observed. The synthesized compounds were obtained at yields of up to 92%, and their structure was unambiguously assigned by x-ray and 2D-NMR experiments. [ABSTRACT FROM AUTHOR]

The 1,4-dicarbonyl scaffold ethyl 3-formyl-4,5-dihydrofuran-2-carboxylate was obtained through the rearrangement of the parent ethyl 2-(4,5-dihydrofuran-3-yl)-2-oxoacetate and applied to the synthesis of a series of 7-alkoxy-2,3-dihydrofuro[2,3- d ]pyridazines. Twelve pyridazines- were obtained in yields of up to 70%. [ABSTRACT FROM AUTHOR]

The regioselective synthesis of twenty novel [3-substituted 5-hydroxy-5-(trifluoromethyl)-4,5-dihydro- 1H -pyrazol-1-yl][6-aryl-(2-methylthio)pyrimidin-4-yl]methanones from the cyclocondensation reactions of new 6-aryl-2-(methylthio)pyrimidine-4-carbohydrazides with 4-substituted 1,1,1-trifluorobut-3-en-2-ones is reported. Human acetylcholinesterase (Hs AChE) and butyrylcholinesterase (Hs BChE) inhibition tests were performed on selected products in order to explore the possible pharmacological applications of these compounds. Two compounds showed significant and selective inhibitory activity for BChE. [ABSTRACT FROM AUTHOR]

Three new series of compounds, 5-alkoxy-3-(trifluoromethyl) penta-2,4-dienenitriles, 5-(phenylthio)-3-(trifluoromethyl)penta-2,4-dienenitriles, and ethyl 4-alkoxy-2-(cyanomethylene)but-3-enoates, obtained from the olefination reaction of the respective enones with diethyl cyanomethylphosphonate via the Horner-Wadsworth-Emmons olefination are reported. All products were obtained as single regioisomers; however, the composition of the stereoisomers changed according to the enone substituents. A study based on ¹H and 13C NMR chemical shifts, ¹H-19F and 13C-19F NMR coupling constants, ¹H NMR signal integrals, and HSQC, HMBC, and NOESY experiments was performed in order to assign the structure and percentage of each stereoisomer obtained. [ABSTRACT FROM AUTHOR]

A simple and efficient procedure for the synthesis of ethyl 2- methylthio- and ethyl 2-benzylthio-6-methyl(aryl)-pyrimidine-4-carboxylates and their corresponding acid derivatives is reported. The products are obtained in good yields via the cyclocondensation reaction of ethyl 4-alkoxy-2-oxo-4-methyl(aryl)-but-3-enoates with 2-methylisothiourea sulfate or 2-benzylisothiourea hydrochloride, under mild, basic, aqueous conditions. [ABSTRACT FROM AUTHOR]

This study reports the synthesis of a new series of pyrazole-isoxazolines, at very good yields, from the cyclocondensation reaction of pyrazole-enaminones with hydroxylamine hydrochloride. Dehydration of the pyrazole-isoxazolines furnished another new series of the respective pyrazole-isoxazoles, at excellent yields. Both series of the obtained compounds were screened for antimycobacterial activity, and compounds 4 f and 5 c showed significant inhibition of bacterial growth with a time- and concentration-dependent bactericidal effect. Cytotoxicity tests in VERO cell line did not indicate toxicity of compounds 4 f and 5 c regarding cellular prediction, NO production or dsDNA release. However, both compounds were associated with an increase in total ROS levels, providing induction of oxidative stress, but without compromising cellular targets. These results highlight compounds 4 f and 5 c as promising candidates for antimycobacterial treatment with a favorable safety profile., (© 2024 Wiley-VCH GmbH.)