76649-96-2Relevant academic research and scientific papers
Non- C2-Symmetric Chiral-at-Ruthenium Catalyst for Highly Efficient Enantioselective Intramolecular C(sp3)-H Amidation
Zhou, Zijun,Chen, Shuming,Hong, Yubiao,Winterling, Erik,Tan, Yuqi,Hemming, Marcel,Harms, Klaus,Houk,Meggers, Eric
, p. 19048 - 19057 (2019/12/04)
A new class of chiral ruthenium catalysts is introduced in which ruthenium is cyclometalated by two 7-methyl-1,7-phenanthrolinium heterocycles, resulting in chelating pyridylidene remote N-heterocyclic carbene ligands (rNHCs). The overall chirality results from a stereogenic metal center featuring either a or Δabsolute configuration. This work features the importance of the relative metal-centered stereochemistry. Only the non-C2-symmetric chiral-at-ruthenium complexes display unprecedented catalytic activity for the intramolecular C(sp3)-H amidation of 1,4,2-dioxazol-5-ones to provide chiral -lactams with up to 99:1 er and catalyst loadings down to 0.005 mol % (up to 11 ?200 TON), while the C2-symmetric diastereomer favors an undesired Curtius-type rearrangement. DFT calculations elucidate the origins of the superior C-H amidation reactivity displayed by the non-C2-symmetric catalysts compared to related C2-symmetric counterparts.
Anticonvulsant properties of histamine H3 receptor ligands belonging to N-substituted carbamates of imidazopropanol
Sadek, Bassem,Shehab, Safa,Wiecek, Malgorzata,Subramanian, Dhanasekaran,Shafiullah, Mohamed,Kiec-Kononowicz, Katarzyna,Adem, Abdu
supporting information, p. 4886 - 4891 (2013/09/02)
Ligands targeting central histamine H3 receptors (H 3Rs) for epilepsy might be a promising therapeutic approach. Therefore, the previously described and structurally strongly related imidazole-based derivatives belonging to carbamate
N-Alkenyl and cycloalkyl carbamates as dual acting histamine H3 and H4 receptor ligands
Wicek, Ma?gorzata,Kottke, Tim,Ligneau, Xavier,Schunack, Walter,Seifert, Roland,Stark, Holger,Handzlik, Jadwiga,Kie?-Kononowicz, Katarzyna
experimental part, p. 2850 - 2858 (2011/06/21)
Previous studies have shown that several imidazole derivatives posses affinity to histamine H3 and H4 receptors. Continuing our study on structural requirements responsible for affinity and selectivity for H3/H4 receptor subtypes, two series of 3-(1H-imidazol-4-yl)propyl carbamates were prepared: a series of unsaturated alkyl derivatives (1-9) and a series possessing a cycloalkyl group different distances to the carbamate moiety (10-13). The compounds were tested for their affinities at the human histamine H3 receptor, stably expressed in CHO-K1 cells. Compounds 1, 2, 5-7, 10-13 were investigated for their affinities at the human histamine H4 receptor co-expressed with Gαi2 and Gβ1γ2 subunits in Sf9 cells. To expand the pharmacological profile, compounds were further tested for their H3 receptor antagonist activity on guinea pig ileum and in vivo after oral administration to mice. All tested compounds exhibited good affinity for the human histamine H3 receptor with Ki values in the range from 14 to 194 nM. All compounds were active in vivo after peroral administration (p.o.) to Swiss mice, thus demonstrating their ability to cross the blood-brain barrier. The most potent H3 receptor ligand of these series was compound 5, 3-(1H-imidazol-4-yl)propyl pent-4-enylcarbamate with the highest affinity (Ki = 14 nM). Additionally, compound 3 showed remarkable central nervous system (CNS) H3R activity, increasing the Nτ-methylhistamine levels in mice with an ED 50 value of 0.55 mg/kg, p.o. evidencing therefore, a twofold increase of inverse agonist/antagonist potency compared to the reference inverse agonist/antagonist thioperamide. In this study, the imidazole propyloxy carbamate moiety was kept constant. The different lipophilic moieties connected to the carbamate functionality in the eastern part of the molecule had a range of influences on the human H4 receptor affinity (154-1326 nM).
SYNTHESIS OF ALIPHATIC ISOCYANATES VIA A TWO-PHASE HOFMANN REACTION
Sy, Anita O.,Raksis, Joseph W.
, p. 2223 - 2226 (2007/10/02)
A convenient method of preparing aliphatic isocyanates via a two-phase Hofmann reaction using a phase transfer catalyst is described.
