Detail of "104599-36-2"

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Pyrazoles

Pyrazoles. 19. Selective thermolysis reactions of bromo-1-nitro-1H-pyrazoles. Formation of 3-nitro-1H- vs. 4-nitro-1H-pyrazoles. Juffermans, J. P. H.; Habraken, Clarisse L. (Dep. Org. Chem.Several reagents such as 104599-36-2 is used here., Univ. Leiden, Leiden 2300 RA, Neth.). J. Org. Chem., 51(24), 4656-60 (English) 1986. CODEN: JOCEAH. ISSN: 0022-3263. DOCUMENT TYPE: Journal CA Section: 28 (Heterocyclic Compounds (More Than One Hetero Atom)) Refluxing 3,4,5-tribromo-1-nitro-1H-pyrazole (I) in benzene results in the evolution of bromine and NO2 and gives 4-nitro-3,5-dibromo-1H-pyrazole (II) and 1-phenyl-3,5-dibromo-4-nitro- and 1-phenyl-3,4,5-tribromo-1H-pyrazole while heating I in toluene gives II and PhCH2Bz. Thermolysis of I in refluxing acetonitrile affords both II and the isomeric 5-nitro-3,4-dibromo-1H-pyrazole (III). Refluxing I mixed with the electron-rich 3,5-dimethyl-1H-pyrazole (IV) in all three solvents gives III and 4-bromo-3,5-dimethyl-1H-pyrazole, whereas refluxing I mixed with anisole in benzene soln. gives II and bromoanisoles. 3,5-Dibromo-1-nitro-1H-pyrazole (V) in refluxing acetonitrile gives mainly III and 3,5-dibromo-1H-pyrazole, but refluxing V mixed with IV affords 3-bromo-5-nitro-1H-pyrazole. .