Aminochlorination reaction with N-chlorophthalimide as a new nitrogen/chlorine source resulting in α-amino derivatives
作者:Yu Qian、Xiaoyun Ji、Wei Zhou、Jianlin Han、Guigen Li、Yi Pan
DOI:10.1016/j.tet.2012.05.066
日期:2012.8
N-chlorophthalimide was reported as an efficient nitrogen/chlorine source for the aminohalogenation of β-nitrostyrenes, which tolerates a wide range of β-nitrostyrenes substrates with good chemical yields, as well as excellent regioselectivities. The resulted vicinal haloamino nitro products have been converted into several other valuable α-amino compounds under simple and mild conditions.
Potassium Carbonate Catalyzed Regioselective Aminohalogenation of β-Nitrostyrenes by Using Benzyl Carbamate/N-Chlorosuccinimide as a New Nitrogen/Chlorine Source
作者:Jianlin Han、Yi Pan、Xiaoyun Ji、Haibo Mei、Yu Qian、Guigen Li
DOI:10.1055/s-0030-1260245
日期:2011.11
A combination of benzyl carbamate and N-chlorosuccinimide was developed as a new system for aminohalogenation of β-nitrostyrenes catalyzed by potassium carbonate in dichloromethane at room temperature. The reaction tolerates a wide range of substituents on the β-nitrostyrene, and proceeds smoothly in good-to-excellent chemical yields (77-99%). The new system shows a high efficiency and it markedly
Approach to Vicinal <i>t</i>-Boc-amino Dibromides via Catalytic Aminobromination of Nitrostyrenes without Using Chromatography and Recrystallization
作者:Hao Sun、Jianlin Han、Padmanabha V. Kattamuri、Yi Pan、Guigen Li
DOI:10.1021/jo302727v
日期:2013.2.1
A 1.0 mol % amount of K3PO4 center dot 3H(2)O was found to catalyze aminohalogenation reaction of nitrostyrenes with N,N-dibromo-tert-butylcarbamate (t-Boc-NBr2) in a dichloroethane system. Good to excellent yields and complete regioselectivity have been achieved by taking advantage of the GAP workup without using traditional purification techniques such as column chromatography and recrystallization. A new mechanism is proposed involving radical and ionic catalytic cycles and an intramolecular migration.
New class of bifunctional thioureas from l-proline: highly enantioselective Michael addition of 1,3-dicarbonyls to nitroolefins
A new class of bifunctional tertiary amine thiourea was synthesized from L-proline. The reported thiourea is amenable to steric and electronic modifications at the stereogenic center bearing a thiourea moiety. Excellent enantioselectivity was obtained in the Michael addition of 2,4-pentanedione to various nitro olefins using the new organocatalyst. The construction of contiguous stereocenters via the Michael reaction of substituted 1,3-dicarbonyls to nitro olefins was also carried out with very good yield, enantioselectivity, and diastereoselectivity. (C) 2014 Elsevier Ltd. All rights reserved.
Identification and<i>in vivo</i>evaluation of a fluorine-18 rolipram analogue, [<sup>18</sup>F]MNI-617, as a radioligand for PDE4 imaging in mammalian brain
作者:David Thomae、Thomas J. Morley、Hsiaoju S. Lee、Olivier Barret、Cristian Constantinescu、Caroline Papin、Ronald M. Baldwin、Gilles D. Tamagnan、David Alagille
DOI:10.1002/jlcr.3389
日期:2016.5.15
R-(-)-rolipram. Herein we describe a small series of rolipram analogs that contain fluoro- or iodo-substituents that could be used as fluorine-18 PET or iodine-123 SPECT PDE4 radiotracers. This series was evaluated with an in vitro binding assay and a 4-(fluoromethyl) derivative of rolipram, MNI-617, was identified, with a five-fold increase in affinity for PDE4 (Kd = 0.26 nM) over R-(-)-rolipram (Kd = 1.6 nM)