1, 1-Disubstituted hydrazines were prepared from the corresponding 1, 1-disubstituted ureas by means of the Hofmann rearrangement reaction. The yields were fairly good, except from the ureas susceptible to oxidation, and thus the present method represents an additional and efficient procedure for the synthesis of 1, 1-disubstituted hydrazines.
We present herein an unprecedented desymmetrization of meso 1,3-diones by enantioselective intermolecular condensation. Under the catalysis by a chiral phosphoric acid, a range of readily available 1,3-diones undergo reaction with hydrazines to produce cyclic and acyclic keto-hydrazones bearing an all-carbon quaternary center in high efficiency and enantioselectivity. These compounds are also highly
A palladium-catalyzed C–N bond coupling reaction between arylhydrazines and aryl tosylates for facile synthesis of unsymmetrical N,N-diarylhydrazines has been developed. Employing the catalyst system of Pd(TFA)2 associated with newly developed phosphine ligand L1, the monoarylation of arylhydrazine proceeds smoothly to afford desired products in good-to-excellent yields (up to 95%) with good functional
Synthesis of pyrazolinylnaphthalic acid derivatives
申请人:——
公开号:US20010012905A1
公开(公告)日:2001-08-09
The invention pertains to a method for preparing derivatives of the pyrazolinylnaphthalic acid having the general formula
1
where Ar
1
and Ar
2
are unsubstituted or substituted phenyl radicals bearing in the para position an alkylated or acylated oxy- or amino group, or a polynuclear aryl radical, and Ar
3
is a substituted N-naphthalimid or 1,8-naphthylene-1′,2′-benzimidazole. Compounds ofthe above general formula are high-efficient red organic luminophors and are used widely as luminescent components of dyes for plastics and liquid scintillators, in hydrogeology to study water streams, to label the chemical industry wastewaters, as laser dyes, etc.