54679-59-3Relevant articles and documents
Consecutive Three-Component Coupling-Addition Synthesis of β-Amino Enoates and 3-Hydroxypyrazoles via Ethyl 3-Arylpropiolates
Niedballa, Jonas,Reiss, Guido J.,Müller, Thomas J. J.
supporting information, p. 5019 - 5024 (2020/07/24)
Two consecutive three-component syntheses furnishing β-amino enoates or 3-hydroxypyrazoles based upon the Sonogashira alkynylation of aryl iodides and ethyl propiolate were established in mostly excellent yields. The ethyl 3-arylpropiolate intermediates are Michael systems which are suited for concatenation with conjugate addition or cyclocondensation giving access to libraries of 21 different β-amino enoates and 17 different 3-hydroxypyrazoles. The rotational barrier of β-pyrrolidino enoates was assessed by studying the coalescence of pyrrolidinyl protons in VT-NMR spectra of electronically different substituted derivatives showing that the electronic substituent effect on the aryl group does not affect the height of the rotational barrier. This indicates that the substituents are essentially oriented orthogonally to the plane of the β-pyrrolidino enoates.
Reactivity of p-Phenyl Substituted β-Enamino Compounds using K-10/ultrasound. I. Synthesis of Pyrazoles and Pyrazolinones
Valduga, Claudete J.,Braibante, Hugo S.,Braibante, Mara E.F.
, p. 189 - 192 (2007/10/03)
The reactivity of the β-enamino ketones, 3-amino-l-(p-phenyl-substituted)-2-buten-l-ones la-d and β-enamino esters. Ethyl-3-amino-3-(p-phenyl-substituted)-2-propenoates 5a-d were evaluated by systematic studies of the reactions with hydrazine and methylhydrazine by reactions with solid support K-10/ultrasound and homogeneous media (reflux in ethanol or dichloromethane) yielding pyrazole rings 2a-d, Af-methylpyrazoles 3a-d, 4a-d and N-methylpyrazolinones 6a-c and 7a-c. The regiochemistry of the cyclization showed dependence of the reaction conditions employed as well as the substituent in the aromatic ring.
Reactivity of p-phenyl substituted β-enamino compounds using K- 10/ultrasound. I. Synthesis of pyrazoles and pyrazolinones
Valduga,Braibante,Braibante
, p. 1453 - 1457 (2007/10/03)
The reactivity of the β-enamino ketones, 3-amino-1-(p-phenyl- substituted)-2-buten-1-ones 1a-d and β-enamino esters, ethyl 3-amino-3-(p- phenyl-substituted)-2-propenoates 5a-d was systematically studied when allowed to react with hydrazine and methylhydrazine under solid support K- 10/ultrasound conditions and in homogeneous media (reflux in ethanol or dichloromethane). The products were pyrazoles 2a-d, N-methylpyrazoles 3a-d, 4a-d and N-methylpyrazolinones 6a-c and 7a-c. The regiochemistry of the cyclization reactions showed dependence upon the reaction conditions employed as well as upon the substituent in the aromatic ring.
