89-95-2Relevant articles and documents
Experimental and theoretical study of the effect of active-site constrained substrate motion on the magnitude of the observed intramolecular isotope effect for the P450 101 catalyzed benzylic hydroxylation of isomeric xylenes and 4,4'-dimethylbiphenyl
Audergon, Christian,Iyer, Krishna R.,Jones, Jeffrey P.,Darbyshire, John F.,Trager, William F.
, p. 41 - 47 (1999)
The validity of a cytochrome P450 (P450) 101 force field developed previously was tested by comparing to published results from other laboratories the predicted regioselectivity and stereoselectivity of both (R)- and (S)-norcamphor oxidation when the force field was used. Once validated, the force field was used to test the hypothesis that the magnitude of an observed intramolecular isotope effect is a function of the distance between equivalent but isotopically distinct intramolecular sites of oxidative attack. Molecular dynamics simulations and kinetic deuterium isotope effect experiments on benzylic hydroxylation were then conducted for a series of selectively deuterated isomeric xylenes and 4,4'-dimethylbiphenyl with P450 101. The molecular dynamics simulations predicted that the rank order of substrate mobility in the active site of P450 101 was o-xylene > p- xylene > dimethylbiphenyl. The observed isotope effects for the trideutero analogues were 10.6, 7.4, and 2.7, for the o-xylene, p-xylene, and 4,4'- dimethylbiphenyl, respectively. Thus, as the theoretically predicted rates of interchange between the isotopically distinct methyl groups decrease, the observed isotope effect decreases. The agreement between the theoretical predictions and experimental results provides strong support for the distance hypothesis stated above and for the potential of computational analysis to enhance our understanding of protein/small molecule interactions.
Deoxygenative hydroboration of primary, secondary, and tertiary amides: Catalyst-free synthesis of various substituted amines
An, Duk Keun,Jaladi, Ashok Kumar,Kim, Hyun Tae,Yi, Jaeeun
, (2021/11/17)
Transformation of relatively less reactive functional groups under catalyst-free conditions is an interesting aspect and requires a typical protocol. Herein, we report the synthesis of various primary, secondary, and tertiary amines through hydroboration of amides using pinacolborane under catalyst-free and solvent-free conditions. The deoxygenative hydroboration of primary and secondary amides proceeded with excellent conversions. The comparatively less reactive tertiary amides were also converted to the corresponding N,N-diamines in moderate yields under catalyst-free conditions, although alcohols were obtained as a minor product.
Sodium Aminodiboranate, a New Reagent for Chemoselective Reduction of Aldehydes and Ketones to Alcohols
Wang, Jin,Guo, Yu,Li, Shouhu,Chen, Xuenian
supporting information, p. 1104 - 1108 (2021/05/25)
Sodium aminodiboranate (NaNH 2(BH 3) 2, NaADBH) is a new member of the old borane family, which exhibits superior performance in chemoselective reduction. Experimental results show that NaADBH can rapidly reduce aldehydes and ketones to the corresponding alcohols in high efficiency and selectivity under mild conditions. There are little steric and electronic effects on this reduction.
Experimental and density functional theory studies on hydroxymethylation of phenylboronic acids with paraformaldehyde over a Rh-PPh3 catalyst
Wang, Kuan,Lan, Jie,He, Zhen-Hong,Cao, Zhe,Wang, Weitao,Yang, Yang,Liu, Zhao-Tie
, (2020/12/01)
The synthesis of benzyl alcohols (BAs) is highly vital for their wide applications in organic synthesis and pharmaceuticals. Herein, BAs was efficiently synthesized via hydroxymethylation of phenylboronic acids (PBAs) and paraformaldehyde over a simple Rh-PPh3 catalyst combined with an inorganic base (NaOH). A variety of BAs with the groups of CH3?, CH3O?, Cl?, Br?, and so on were obtained with moderate to good yields, indicating that the protocol had a good universality. Density functional theory (DFT) calculations proposed the Hayashi-type arylation mechanism involved the arylation step of PBA and Rh(OH)(PPh3)2 catalyst to form Rh(I)-bound aryl intermediates and the hydrolysis step of Rh(I)-bound aryl intermediates and HCHO to generate BA product (the rate-determining step). The present route provides a valuable and direct method for the synthesis of BAs and expands the application range of paraformaldehyde.