Effect of “anomalous” electrochemical halogenation of pyrazoles and its reasons
作者:B. V. Lyalin、V. A. Petrosyan
DOI:10.1007/s11172-012-0030-9
日期:2012.1
the nature of halo gen determines, to a noticeable extent, the yield of target products in the electrochemical halogenation of pyrazoles in aqueoussolutions of alkaline metal halides. It is known4 that pyrazole halogenation proceeds via the mechanism of electrophilic aromaticsubstitution, and the reactivity of halogen in these reaction decreases in the series Cl > Br > I. This is consistent with the
Keratin dyeing compounds, keratin dyeing compositions containing said compounds, and use thereof
申请人:The Procter & Gamble Company
公开号:US07850742B2
公开(公告)日:2010-12-14
Compositions for the oxidative dyeing of keratin fibers, comprising a medium suitable for dyeing and at least one 3-substituted pyrazole keratin dyeing compound and derivatives thereof. A method for oxidative dyeing of keratin fibers, comprising applying such compositions in the presence of an oxidizing agent, for a period sufficient to develop the desired coloration.
Process for the synthesis of 4,5-diaminopyrazole derivatives useful for
申请人:Wella Aktiengesellschat
公开号:US05663366A1
公开(公告)日:1997-09-02
The subject matter of the present invention is directed to a process for producing 4,5-diaminopyrazole derivatives of the general formula (I) ##STR1## where R.sub.1 and R.sub.2 independently designate hydrogen, a C.sub.1 - to C.sub.6 -alkyl radical or a C.sub.2 - to C.sub.4 -hydroxyalkyl radical, which can be used as dye precursors, for example for hair dyes, and to new pyrazole derivatives. When using the process according to the invention good yields of isomer-pure 4,5-diaminopyrazole derivatives of general formula (I) can be obtained.
Keratin Dyeing Compounds, Keratin Dyeing Compositions Containing Said Compounds, and Use Thereof
申请人:Dahlgren Richard Marc
公开号:US20090282622A1
公开(公告)日:2009-11-19
Compositions for the oxidative dyeing of keratin fibers, comprising a medium suitable for dyeing and at least one 3-substituted pyrazole keratin dyeing compound and derivatives thereof. A method for oxidative dyeing of keratin fibers, comprising applying such compositions in the presence of an oxidizing agent, for a period sufficient to develop the desired coloration.