37677-17-1Relevant academic research and scientific papers
Lithium Chloride Catalyzed Asymmetric Domino Aza-Michael Addition/[3 + 2] Cycloaddition Reactions for the Synthesis of Spiro- and Bicyclic α,β,γ-Triamino Acid Derivatives
Just, David,Hernandez-Guerra, Daniel,Kritsch, Susanne,Pohl, Radek,Císa?ová, Ivana,Jones, Peter G.,Mackman, Richard,Bahador, Gina,Jahn, Ullrich
, p. 5213 - 5221 (2018)
Angularly and peri-fused tricyclic pyrrolidinopyrazolines are efficiently prepared by LiCl-catalyzed domino aza-Michael addition-1,3-dipolar cycloaddition reactions. The absolute stereochemistry is controlled in the aza-Michael addition step, nonaflyl azide serves as effective diazo transfer reagent to the formed enolate and the resulting diazo dipole engages in the 1,3-dipolar cycloaddition step. The resulting tricyclic pyrrolidinopyrazolines can be easily transformed to enantiomerically enriched nonproteinogenic spirocyclic α,β,γ-triamino acids, angularly or peri-fused tricyclic β-prolines or pyrimidines. The activity of the tricyclic amino acid derivatives against the hepatitis C virus was determined.
Regiospecific Synthesis of Calcium-Independent Daptomycin Antibiotics using a Chemoenzymatic Method
Mupparapu, Nagaraju,Lin, Yu-Hsin Cindy,Kim, Tae Ho,Elshahawi, Sherif I.
supporting information, p. 4176 - 4182 (2021/02/01)
Daptomycin (DAP) is a calcium (Ca2+)-dependent FDA-approved antibiotic drug for the treatment of Gram-positive infections. It possesses a complex pharmacophore hampering derivatization and/or synthesis of analogues. To mimic the Ca2+-binding effect, we used a chemoenzymatic approach to modify the tryptophan (Trp) residue of DAP and synthesize kinetically characterized and structurally elucidated regiospecific Trp-modified DAP analogues. We demonstrated that the modified DAPs are several times more active than the parent molecule against antibiotic-susceptible and antibiotic-resistant Gram-positive bacteria. Strikingly, and in contrast to the parent molecule, the DAP derivatives do not rely on calcium or any additional elements for activity.
Pyrrolidines and Piperidines by Ligand-Enabled Aza-Heck Cyclizations and Cascades of N-(Pentafluorobenzoyloxy)carbamates
Hazelden, Ian R.,Carmona, Rafaela C.,Langer, Thomas,Pringle, Paul G.,Bower, John F.
, p. 5124 - 5128 (2018/03/26)
Ligand-enabled aza-Heck cyclizations and cascades of N-(pentafluorobenzoyloxy)carbamates are described. These studies encompass the first examples of efficient non-biased 6-exo aza-Heck cyclizations. The methodology provides direct and flexible access to carbamate protected pyrrolidines and piperidines.
Stereospecific Alkene Aziridination Using a Bifunctional Amino-Reagent: An Aza-Prilezhaev Reaction
Farndon, Joshua J.,Young, Tom A.,Bower, John F.
supporting information, p. 17846 - 17850 (2019/01/04)
In situ deprotection (TFA) of O-Ts activated N-Boc hydroxylamines triggers intramolecular aziridination of N-tethered alkenes to provide complex N-heterocyclic ring systems. Synthetic and computational studies corroborate a diastereospecific aza-Prilezhaev-type mechanism. The feasibility of related intermolecular alkene aziridinations is also demonstrated.
Carbene-catalyzed desymmetrization of 1,3-diols: Access to optically enriched tertiary alkyl chlorides
Li, Bao-Sheng,Wang, Yuhuang,Proctor, Rupert S. J.,Jin, Zhichao,Chi, Yonggui Robin
, p. 8313 - 8316 (2016/07/06)
The introduction of a chlorine atom to a carbon center in an enantioselective manner via conventional C-Cl bond formation is difficult. Here we report a new approach to this class of tertiary alkyl chlorides with high optical purities. Instead of forming a new C-Cl bond, our approach involves carbene-catalyzed desymmetrization of 2-chloro-1,3-diols as the key step to set up the chiral carbon center with excellent enantiomeric excess.
Diverse N-Heterocyclic Ring Systems via Aza-Heck Cyclizations of N-(Pentafluorobenzoyloxy)sulfonamides
Hazelden, Ian R.,Ma, Xiaofeng,Langer, Thomas,Bower, John F.
, p. 11198 - 11202 (2016/10/13)
Aza-Heck cyclizations initiated by oxidative addition of Pd0-catalysts into the N?O bond of N-(pentafluoro-benzoyloxy)sulfonamides are described. These studies, which encompass only the second class of aza-Heck reaction developed to date, provide direct access to diverse N-heterocyclic ring systems.
HETEROARYL COMPOUNDS USEFUL AS INHIBITORS OF SUMO ACTIVATING ENZYME
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, (2015/01/16)
Disclosed are compounds of formula (I): or a pharmaceutically acceptable salt thereof; wherein Y, Ra, Ra', Rc, Rf, X2, Rd, Rd', Re, Re', m, and G have the values described herein and stereochemical configurations depicted at asterisked positions indicate absolute stereochemistry, useful as inhibitors of Sumo Activating Enzyme (SAE). Further provided are pharmaceutical compositions comprising a compound of the disclosure and methods of using the compositions in the treatment of proliferative, inflammatory, cardiovascular and neurodegenerative diseases or disorders.
Palladium catalyzed cyclizations of oxime esters with 1,1-disubstituted alkenes: Synthesis of α,α-disubstituted dihydropyrroles and studies towards an asymmetric protocol
Faulkner, Adele,Scott, James S.,Bower, John F.
, p. 1521 - 1523 (2013/03/13)
We report efficient Pd-catalyzed cyclizations of oxime esters with 1,1-disubstituted alkenes as the basis of a general entry to α,α-disubstituted pyrrolidine derivatives. We also demonstrate that catalytic asymmetric variants of this chemistry are feasible by employing a suitable chiral ligand. The Royal Society of Chemistry 2013.
Tandem ring-opening/ring-closing metathesis polymerization: Relationship between monomer structure and reactivity
Park, Hyeon,Lee, Ho-Keun,Choi, Tae-Lim
supporting information, p. 10769 - 10775 (2013/08/23)
Monomers containing either cycloalkenes with low ring strain or 1-alkynes are poor monomers for olefin metathesis polymerization. Ironically, keeping two inactive functional groups in proximity within one molecule can make it an excellent monomer for metathesis polymerization. Recently, we demonstrated that monomer 1 having cyclohexene and propargyl moieties underwent rapid tandem ring-opening/ring-closing metathesis (RO/RCM) polymerization via relay-type mechanism. Furthermore, living polymerization was achieved when a third-generation Grubbs catalyst was used. Here, we present a full account on this tandem polymerization by investigating how various structural modifications of the monomers affected the reactivity of the tandem polymerization. We observed that changing the ring size of the cycloalkene moieties, the length of the alkynes, and linker units influenced not only the polymerization rates but also the reactivities of Diels-Alder reaction, which is a post-modification reaction of the resulting polymers. Also, the mechanism of tandem polymerization was studied by conducting end-group analysis using 1H NMR analysis, thereby concluding that the polymerization occurred by the alkyne-first pathway. With this mechanistic conclusion, factors responsible for the dramatic structure-reactivity relationship were proposed. Lastly, tandem RO/RCM polymerization of monomers containing sterically challenging trisubstituted cycloalkenes was successfully carried out to give polymer repeat units having tetrasubstituted cycloalkenes.
SPIROCYCLIC DIHYDRO-THIAZINE AND DIHYDRO-OXAZINE BACE INHIBITORS, AND COMPOSITIONS AND USES THEREOF
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Page/Page column 132; 133, (2013/10/08)
Compounds are provided having a structure according to Formula (I): wherein A1, A2, A3, Y, R 1, R2, R3, R4, R5, R6, m, n and p are defined herein. Further provided are pharmaceutical compositions including the compounds provided and methods of making and using the compounds and compositions as provided, e.g., in the treatment and prevention of various disorders, such as Alzheimer's disease.
