23277-00-1Relevant academic research and scientific papers
Stereoselective synthesis of 2(S)-(1,1-dimethylethylsulfonylmethyl)-3-(1- naphthyl)-propionic acid, building block for protease inhibitors via asymmetric hydrogenation
Beck,Jendralla,Kammermeier
, p. 4691 - 4698 (1994)
Title compound 1b (purity > 99%, 99.6% ee) is synthesized (100g scale) from commercial 3-bromo-pyruvic acid in six steps with an overall yield of 16%. The sequence is operationally simple and devoid of chromatographic purifications. Key step is the asymmetric hydrogenation of a substrate with sulfur functionality.
Novel carbazole skeleton-based photoinitiators for led polymerization and LED projector 3D printing
Mousawi, Assi Al,Garra, Patxi,Dumur, Frédéric,Bui, Thanh-Tuan,Goubard, Fabrice,Toufaily, Joumana,Hamieh, Tayssir,Graff, Bernadette,Gigmes, Didier,Fouassier, Jean Pierre,Lalevée, Jacques
supporting information, (2018/01/12)
Radical chemistry is a very convenient way to produce polymer materials. Here an application of a particular photoinduced radical chemistry is illustrated. Seven new carbazole derivatives Cd1–Cd7 are incorporated and proposed as high performance near-UV photoinitiators for both the free radical polymerization (FRP) of (meth)acrylates and the cationic polymerization (CP) of epoxides utilizing Light Emitting Diodes LEDs @405 nm. Excellent polymerization-initiating abilities are found and high final reactive function conversions are obtained. Interestingly, these new derivatives display much better near-UV polymerization-initiating abilities compared to a reference UV absorbing carbazole (CARET 9H-carbazole-9-ethanol) demonstrating that the new substituents have good ability to red shift the absorption of the proposed photoinitiators. All the more strikingly, in combination with iodonium salt, Cd1–Cd7 are likewise preferred as cationic photoinitiators over the notable photoinitiator bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO) for mild irradiation conditions featuring their remarkable reactivity. In particular their utilization in the preparation of new cationic resins for LED projector 3D printing is envisioned. A full picture of the included photochemical mechanisms is given.
Stereopure Functionalized Benzosultams via Ruthenium(II)-Catalyzed Dynamic Kinetic Resolution-Asymmetric Transfer Hydrogenation
Jeran, Marko,Cotman, Andrej Emanuel,Stephan, Michel,Mohar, Barbara
supporting information, p. 2042 - 2045 (2017/04/28)
A highly diastereo- and enantioselective Ru(II)-catalyzed dynamic kinetic resolution-asymmetric transfer hydrogenation (DKR-ATH) of α-(N-sulfonylimino) and α-(N-sulfonylamino) aryl ketones to 4-hydroxy-benzo-δ- and 3-(α-hydroxy-arylmethyl)-benzo-γ-sultams is presented. By employing enantiopure ansa-Ru[PipSO2DPEN(CH2)4Ph] cat. II with S/C = 10 000 in a HCO2H/Et3N binary mix, up to >99.9% ee and dr >99:1 are obtained with 100% conversion under mild conditions. Application to access the stereopure "structurally simplified TsDPEN" N,N-ligand syn-3-(α-aminobenzyl)-benzo-γ-sultam ("syn-ULTAM") and its structural isomer trans-4-amino-3-phenyl-benzo-δ-sultam (trans-4) is demonstrated.
1-[(E)-2-arylethenyl]-2,2-diphenylcyclopropanes: Kinetics and mechanism of rearrangement to cyclopentenes
Mulzer, Johann,Huisgen, Rolf,Arion, Vladimir,Sustmann, Reiner
experimental part, p. 1359 - 1388 (2011/10/09)
Kinetic measurements for the thermal rearrangement of 2,2-diphenyl-1-[(E)- styryl]cyclopropane (22a) to 3,4,4-triphenylcyclopent-1-ene (23a) in decalin furnished ΔHρm{{-{isom}^{ne }}}$=31.0±1.2kcal mol-1 and ΔSρm{{-{isom}^{ne }}}$=-6. 0±2.6e.u. The lowering of ΔHa‰ by 20kcal mol-1, compared with the rearrangement of the vinylcyclopropane parent, is ascribed to the stabilization of a transition structure (TS) with allylic diradical character. The racemization of (+)-(S)-22a proceeds with ΔHρm{{-{rac}^{ne }}}$=28.2±0.8kcal mol -1 and ΔSρm{{-{rac}^{ne }}}$=-5±2e.u., and is at 150° 106 times faster than the rearrangement. Seven further 1-(2-arylethenyl)-2,2-diphenylcyclopropanes 22, (E)- and (Z)-isomers, were synthesized and characterized. The (E)-compounds showed only modest substituent influence in their krac (at 119.4°) and kisom (at 159.3°) values. The lack of solvent dependence of rate opposes charge separation in the TS, but a linear relation of log krac with log p.r.f., i.e., partial rate factors of radical phenylations of ArH, agrees with a diradical TS. The ring-opening of the preponderant s-trans-conformation of 22 gives rise to the 1-exo-phenylallyl radical 26 that bears the diphenylethyl radical in 3-exo-position, and is responsible for racemization. The 1-exo-3-endo-substituted allylic diradical 27 arises from the minor s-gauche-conformation of 22 and is capable of closing the three- or the five-membered ring, 22 or 23, respectively. The discussion centers on the question whether the allylic diradical is an intermediate or merely a TS. Quantum-chemical calculations by Houk etal. (1997) for the parent vinylcyclopropane reveal the lack of an intermediate. Can the conjugation of the allylic diradical with three Ph groups carve the well of an intermediate? Copyright
Process for the stereoselective synthesis of 3-substituted 2-sulfonylmethylpropionic acids, and intermediate products
-
, (2008/06/13)
Compounds of the formula I STR1 can be prepared in a multi-day process starting from the compounds of the formulae II and III
Synthesis and Stereochemical Characterization of Some Optically Active 1,2-Dinaphthylethane-1,2-diols
Rosini, Carlo,Scamuzzi, Simone,Uccello-Barretta, Gloria,Salvadori, Piero
, p. 7395 - 7400 (2007/10/02)
Three new diols, 1,2-di(2-naphthyl)ethane-1,2-diol, 1-(1-naphthyl)-2-(2-naphthyl)ethane-1,2-diol, and 1,2-di(1-naphthyl)ethane-1,2-diol, have been prepared in optically active form by catalytic asymmetric syn-dihydroxylation of the corresponding (E)-olefins.The complete stereochemical characterization was easily accomplished by transforming them into the corresponding isopropyiidene ketals.These derivatives can be separated by HPLC on a Chiralcel OD column allowing the determination of the ee, and at same time, their CD spectra have been analyzed, allowing a safe assignment of absolute configuration in conjunction with molecular mechanics calculations and an exciton-coupling treatment.
Anti-hypertensive piperidine compounds
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, (2008/06/13)
Novel compounds of the formula: STR1 are described wherein Z is a bicyclic aryl group containing between 9 and 10 ring atoms, up to two of which may be nitrogen and up to one of which may be oxygen or sulfur; A is an ethenyl group which may be lower-alkyl-substituted; and R and R' each represent H or an aliphatic group of 1-4 carbon atoms; or a pharmaceutically acceptable acid addition salt thereof.
Approaches to Protection against Nerve Agent Poisoning. (Naphthylvinyl)pyridine Derivatives as Potential Antidotes
Gray, Allan P.,Platz, Robert D.,Henderson, Theresa R.,Chang, Timothy C. P.,Takahashi, Kazuyuki,Dretchen, Kenneth L.
, p. 807 - 814 (2007/10/02)
Analogues of the potent inhibitor of choline acetyltransferase (CAT) (E)-4-(1-naphthylvinyl)pyridine methiodide were synthesized and evaluated for their ability to inhibit CAT and protect against nerve agent intoxication.Several compounds, notably (E)-1-(2-hydroxyethyl)-(1-naphthylvinyl)pyridinium bromide (3), (E)-1-methyl-4-(1-naphthylvinyl)-1,2,3,6-tetrahydropyridine hydrochloride (22), and (E)-1-methyl-4-(1-naphthylvinyl)piperidine hydrochloride (23), were found to afford significant protection against sarin in the mouse and against soman in the giunea pig.However, protection was apparently not related to CAT inhibition.Compound 23, our most effective compound in protecting against nerve agent, was without CAT inhibitory activity.Compound 22, which proved to be a potent CAT inhibitor, most likely owed this activity to being dehydrogenated back to the pyridinium quaternary salt by oxidative enzymes.Several of the (naphthylvinyl)pyridine quaternary salts, but not their tertiary amine analogues, were found to be effective in slowing the rate of aging of soman-inhibited acetylcholinesterase.Ability to slow the rate of aging was enhanced by introduction of methoxy substituents on the aryl moiety whereas the aging rate was actually accelerated by chloro substituents.To date, our most effective compound in slowing the rate of aging, (E)-4-pyridine methochloride (6), did not provide significant protection against soman in the mouse.
INTRODUCTION OF METHYL GROUPS INTO POLYCYCLIC COMPOUNDS THROUGH THE PHOSPHONIUM SALTS OF METHYLNAPHTHALENE AND 9-METHYLPHENANTHRENE
Listvan, V. N.,Stasyuk, A. P.
, p. 354 - 359 (2007/10/02)
Chloromethyl derivatives synthesized by the chloromethylation of naphthalene and methylnaphthalenes were converted into the corresponding triphenylphosphonium salts.Alkaline hydrolysis of the latter gave 1-methylnaphthalene and some di-, tri-, and tetramethylnaphthalenes. 9-Methylphenanthrene was obtained similarly from phenanthrene.The corresponding diarylethenes were synthesized from the phosphonium salts by the Wittig reaction.
