2621-73-0Relevant articles and documents
Preparation of a novel bromine complex and its application in organic synthesis
Nishio, Yuya,Yubata, Kotaro,Wakai, Yutaro,Notsu, Kotaro,Yamamoto, Katsumi,Fujiwara, Hideki,Matsubara, Hiroshi
, p. 1398 - 1405 (2019/02/07)
Although molecular bromine (Br2) is a useful brominating reagent, it is not easy to handle. Herein, we describe the preparation of a novel air-stable bromine complex prepared from 1,3-dimethyl-2-imidazolidinone (DMI) and Br2, which was identified to be (DMI)2HBr3 by spectral and X-ray techniques. This complex was then used to brominate olefins, carbonyl compounds, and aromatics, as well as in the Hofmann rearrangement. Yields of reaction products using this complex were almost the same or superior to those using other bromine alternatives.
Cu(II)-ion-catalyzed solvolysis of N,N- bis(2-picolyl)ureas in alcohol solvents: Evidence for cleavage involving nucleophilic addition and strong assistance of bis(2-picolyl)amine leaving group departure
Belzile, Mei-Ni,Neverov, Alexei. A.,Brown, R. Stan
, p. 7916 - 7925 (2014/08/18)
The kinetics and products for solvolysis of N-p-nitrophenyl-N′, N′-bis(pyridin-2-ylmethyl) urea (7a), N-methyl-N-p-nitrophenyl-N′, N′-bis(pyridin-2-yl methyl) urea (7b), and N-phenyl-N′,N′- bis(pyridin-2-yl-methyl) urea (DPPU) (7c) promoted by Cu(II) ion in methanol and ethanol were studied under sspH-controlled conditions at 25 °C. Methanolysis and ethanolysis of these substrates proceeds rapidly at a 1:1 ratio of substrate:metal ion, the half-times for decomposition of the Cu(II):7a complexes being ～150 min in methanol and 15 min in ethanol. In all cases, the reaction products are the Cu(II) complex of bis(2-picolyl)amine and the O-methyl or O-ethyl carbamate of the parent aniline, signifying that the point of cleavage is the bis(2-picolyl) - N - C - O bond. Reactions of the Cu(II):7b complexes in each solvent proceed about 3-5 times slower than their respective Cu(II):7a complexes, excluding an elimination mechanism that proceeds through an isocyanate which subsequently adds alcohol to give the observed products. The reactions also proceed in other solvents, with the order of reactivity ethanol > methanol >1-propanol >2-propanol > acetonitrile (with 0.2% methanol) > water spanning a range of 150-fold. The mechanism of the reactions is discussed, and the reactivity and mode of cleavage are compared with that of the M(II)-promoted ethanolytic cleavage of a mono-2-picolyl derivative, N-p-nitrophenyl-N′-(pyridin-2-yl-methyl) urea (4a), which had previously been shown to cleave at the aniline N-C - O bond. The large estimated acceleration of the rate of attack of ethoxide on 7b of at least 2 × 1016 provided by associating Cu(II) with the departing group in this urea is discussed in terms of a trifunctional role for the metal ion involving Lewis acid activation of the substrate, intramolecular delivery of a Cu(II)-coordinated ethoxide, and metal-ion-assisted leaving group departure.
New and simple synthesis of acid azides, ureas and carbamates from carboxylic acids: Application of peptide coupling agents EDC and HBTU
Sureshbabu, Vommina V.,Lalithamba,Narendra,Hemantha
experimental part, p. 835 - 840 (2010/06/20)
Conversion of carboxylic acids into acid azides using peptide coupling agents, EDC and HBTU is described. The procedure is efficient, practical and applicable to a diverse range of carboxylic acids including N-protected amino acids. Using the same reagents, one-pot synthesis of ureas, dipeptidyl urea esters and carbamates from acids has also been achieved. The Royal Society of Chemistry 2010.
