- Noncovalent Interactions in Ir-Catalyzed C-H Activation: L-Shaped Ligand for Para-Selective Borylation of Aromatic Esters
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An efficient strategy for the para-selective borylation of aromatic esters is described. For achieving high para-selectivity, a new catalytic system has been developed modifying the core structure of the bipyridine. It has been proposed that the L-shaped ligand is essential to recognize the functionality of the oxygen atom of the ester carbonyl group via noncovalent interaction, which provides an unprecedented controlling factor for para-selective C-H activation/borylation.
- Hoque, Md Emdadul,Bisht, Ranjana,Haldar, Chabush,Chattopadhyay, Buddhadeb
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supporting information
p. 7745 - 7748
(2017/06/21)
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- Preparation method of N,N-dimethyl benzoate composite
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The invention relates to a preparation method of an N,N-dimethyl benzoate composite, in particular to a preparation method for preparing N,N-dimethyl benzoate by using N,N-dimethylaniline, bi(trichloromethyl)carbonic ester and alcohol as raw materials. The raw materials are cheap and easy to obtain, the yield is high, a midbody does not need to be purified, a continuous reaction can be performed without replacing solvents, the preparation method is cheap, environmentally friendly, easy to implement and suitable for industrialization, and the method can be used for preparing the important chemical and medical midbody through N,N-dimethyl benzoyl chloride.
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Paragraph 0031
(2016/10/09)
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- Mono-N-methylation of functionalized anilines with alkyl methyl carbonates over NaY faujasites. 4. Kinetics and selectivity
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(Chemical Equation Presented) In the presence of NaY faujasite as the catalyst, the reaction of bifunctional anilines (1-4: XC6H 4-NH2; X = OH, CO2H, CH2OH, and CONH2) with methyl alkyl carbonates [MeOCO2R′: R′ = Me or MeO(CH2)2O(CH2)2] proceeds with a very high mono-N-methyl selectivity (XC6H 4NHMe up to 99%), and chemoselectivity as well, with other nucleophilic functions (OH, CO2H, CH2OH, CONH2) fully preserved from alkylation and/or transesterification reactions. Aromatic substituents, however, modify the relative reactivity of amines 1-4: good evidence suggests that, not only steric and electronic effects, but, importantly, direct acid-base interactions between substituents and the catalyst are involved. Weakly acidic groups (OH, CH2OH, CONH2, pKa ≥ 10) may help the reaction, while aminobenzoic acids (pK a of 4-5) are the least reactive substrates. The solvent polarity also affects the reaction, which is faster in xylene than in the more polar diglyme. The mono-N-methyl selectivity is explained by the adsorption pattern of reagents within the zeolite pores: a BAl2 displacement of the amine on methyl alkyl carbonate should occur aided by the geometric features of the NaY supercavities. Different factors account for the reaction chemoselectivity. Evidence proves that the polarizability of the two nucleophilic terms (NH 2 and X groups) of anilines is relevant, although adsorption and confinement phenomena of reagents promoted by the zeolite should also be considered.
- Selva, Maurizio,Tundo, Pietro,Foccardi, Tommaso
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p. 2476 - 2485
(2007/10/03)
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