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Selectivity Studies Towards the Synthesis of Novel Biaryl Ureas by (Hetero)Nanocatalysis: Size Control and Support Effects
Author(s) -
Senra Jaqueline D.,
Viana Gil M.,
Malta Luiz Fernando B.,
Simas Alessandro B. C.,
Aguiar Lucia C. S.
Publication year - 2016
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201500889
Subject(s) - catalysis , phenylboronic acid , particle size , alkyl , palladium , chemistry , urea , aryl , selectivity , cyclodextrin , heterogeneous catalysis , nanoparticle , combinatorial chemistry , chemical engineering , organic chemistry , nanotechnology , materials science , engineering
Abstract A series of novel biaryl ureas containing different structural patterns have been prepared in good yields in the presence of palladium nanoparticles (PdNPs) with narrow particle size distribution. In particular, α, β‐, and γ‐hydroxypropylated cyclodextrins were used as reductants/stabilizers under different Pd‐to‐cyclodextrin ratios to tune the particle size and exploit the surface/cavity effects in the Suzuki–Miyaura reaction. Catalyst recovery in this process was pursued as well. Owing to its excellent performance, ceria was explored as a support for these PdNPs. The heterogeneous catalyst was characterized and investigated in the reaction of N ‐(4‐iodo‐aryl), N ′‐alkyl urea and phenylboronic acid. Our preliminary results revealed a high activity of the catalyst at 0.5 mol % Pd 0 during three consecutive cycles. It is suggested that the specific interface between Pd 0 and the high‐surface‐area ceria has a role in the catalytic performance.