Nickel-Catalyzed C-O Cross-Coupling Reaction at Low Catalytic Loading with Weak Base Participation
Herein, we report a nickel-catalyzed crossing-coupling reaction for the synthesis of diaryl ethers. The desired products are achieved by coupling heterocyclic alcohols with aryl bromides bearing strong electron withdrawing nitro group under the catalyst system of NiCl2(PPh3)2 and weak base KHCO3. This mild reaction exhibits a broad functional group tolerance. Compound 4 as an important intermediate is suitable for further structural modification of MALT1 inhibitor MI-2.
Phase-transfer catalyzed acylation of 5(3)-hydroxy-3(5)-substituted-1H- pyrazoles
PTC acylation of 5(3)-hydroxy-3(5)-substituted-1H-pyrazoles by different acyl halide reagents at 25°C in the presence of tetrabutylammonium bromide as catalyst has been investigated. This work is aiming to study the comparison of N-versus O- and C-acylati
Khalil, Ali Kh.,Hassan, Mohamed A.,Mohamed, Mohamed M.,El-Sayed, Abeer M.
p. 2485 - 2490
(2007/10/03)
An experimental (flash vacuum pyrolysis) and theoretical study of the tautomerism of pyrazolinones at high temperatures
Flash vacuum pyrolysis experiments were carried out between 500 and 800°C on 3(5)-phenyl- and 3(5)-methylpyrazolinones and on 3(5)-methoxy-5(3)-phenylpyrazole. The origin of the isolated products (mainly indanone, hydroxyalkynes and α,β-unsaturated aldehydes) can be explained as arising from the hydroxy tautomers of pyrazolinones. Temperature effects on the tautomeric equilibrium of 1-phenyl-3-methylpyrazolinone in solution show that the percentage of the CH tautomer increases with the temperature. MP2 ab initio calculations on the model compound, pyrazolinone itself, have been used to rationalize these findings. The problem of the aromaticity of the four tautomers of pyrazolinone has been examined through Schleyer's NICS (nuclear independent chemical shifts) calculations.
Yranzo, Gloria I.,Moyano, Elizabeth L.,Rozas, Isabel,Dardonville, Christophe,Elguero, Jose
p. 211 - 216
(2007/10/03)
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