Synthesis of 1-methyl-, 4-nitro-, 4-amino- and 4-iodo-1,2-dihydro-3H-pyrazol-3-ones
(EN)
Fiamegos, Y. C.
(EN)
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
(EL)
Fiamegos, Y. C.
(EN)
4-Aminopyrazole-3-ones 4b, e, f were prepared from pyrazole-3-ones 1b-d in a four-step reaction sequence. Reaction of the latter with methyl p-toluenesulfonate gave 1-methylpyrazol-3-ones 2b-d. Compounds 2b-d were treated with aqueous nitric acid to give 4-nitropyrazol-3-ones 3b-d. Reduction of compounds 3b-d by catalytic hydrogenation with Pd-C afforded the 4-amino compounds 4b, e, C Using similar reaction conditions, nitropyrazole-3-ones derivatives 2c, d were reduced into aminopyrazole-3-ones 5e, f. 4-lodopyrazole-3-ones 7a, 7c and 8 were prepared from the corresponding pyrazol-3-ones 2a, 2c and 6 and iodine monochloride or sodium azide and iodine monochloride.
(EN)
