Furoxans are potentially useful heteroaromatic units in pharmaceuticals and agrichemicals. However, the applications for furoxan-based compounds have been hampered due to the underdevelopment of their synthetic methods. Herein, we report a new synthetic approach for the synthesis of chloro- and bromofuroxans. The starting materials were dichloro- and dibromofuroxans, and the substituents were directly
An expedient synthesis of (±)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid hydrobromide<i>via</i>a 3-bromoisoxazole intermediate
作者:Robert N. Hanson、Farid A. Mohamed
DOI:10.1002/jhet.5570340155
日期:1997.1
The excitatory, amino acid ±2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionicacid hydrobromide was prepared in gram quantities in an 3.3% overall yield from methylbut 2-ynoate. The key step was the facile preparation of methyl 3-bromo-5-methylisoxazole-4-carboxylate.
1,3-Dipolar cycloaddition synthesis of 3-bromo-5-substituted isoxazoles, useful intermediates for the preparation of pharmacologically active compounds
作者:D. Chiarino、M. Napoletano、A. Sala
DOI:10.1002/jhet.5570240109
日期:1987.1
monosubstituted acetylenic derivatives 4 to give 3-bromo-5-substituted isoxazoles 5 in high yield. The experimental conditions necessary to overcome difficulties such as the low reactivity of acetylenicdipolarophiles and the high tendency to dimerization of bromonitrile oxide 2, are discussed; the regioselectivity of this 1,3-dipolar cycloaddition is also studied. The obtained improvements in the synthesis of