Synthesis of New Chiral C_2-Symmetrical Bis(oxazoline) Compounds

New chiral C_2-symmetrical bis(oxazoline) compounds bearing one isobutyl-, secbutyl-, benzyl- or isopropyl-substituent at the 4-position have been prepared and characterized.

Synthesis of binaphthyl bridged chiral bis-corrole

Chiral bis-corrole 1 and 2 were prepared by reaction of （s）-2,2′-bis（bromomethyl）-1, 1′-binaphthyl and 10-（4-hydroxylphenyl）- 5,15-bis（pentafluorophenyl）corrole or 10-（3-hydroxylphenyl）-5,15-bis（pentafluorophenyl）corrole in DMF at 60 ℃ in the presence of anhydrous K2CO3 with an isolated yield -8%. Both 1 and 2 exhibit unsymmetrical induced circular dichroism （ICD） in the soret band with positive exciton chirality.

Chiral Synthesis of 13-Acetyl-12-hydroxy-podocarpane-8,11,13-triene-7-one

An enantioselective synthetic route to (+)-13-acetyl-12-hydroxy-podocarpane-8,11,13-triene-7-one 1a and (-)-13-acetyl-12-hydroxy-podocarpane-8,11,13-triene-7-one 1b was developed from (S)-(-)-alpha -cyclocitral 8a and (R)-(+)-alpha -cyclocitral 8b.

Synthesis of Novel C_2-Symmetric Chiral Polyamide Macrocycles Containing Pyridyl Side-arm

Three novel C2-symmetric macrocycles containing pyridyl units have been prepared by the cyclic condensation of chiral diamide intermediates with 2,6-pyridinedicarbonyl dichloride in highly diluted solution at room temperature.

Enantioselective Synthesis of Chiral 1-Ferrocenyl Alcohol via CBS-Reduction

Reduction of prochiral ferrocenyl ketones 2a-e in the presence of 10 mol% of chiral beta -amino alcohols 4a-b provides 1-ferrocenyl alcohols 1a-e in high yields (> 85%) with high optically purity (e.e. up to 96%).

The Synthesis of a New Type of Calixarene with Chiral Pendant

Two new chiral calixarenes were synthesized by condensing 1,3 bis chlorocarbomethyl calixarenes with (1S, 2S) 2 amino 1 (4 nitrophenyl) 1,3 propanediol, a by product from antibiotic industry , and were characterized by 1H NMR , MS FAB, and elemental analysis. The 1H NMR spectra show that those molecules assume a cone conformation in solution.

Facile Synthesis of Chiral Conjugated Polymer Based on BINOL Skeleton

A new type of chiral conjugated polymers 6a-d has been synthesized by the reaction of (R)-2,2'-dihydroxy-1,1'-binaphthyl-6,6'-dicarbaldehyde 5 with corresponding diamine in the presence of acetic acid.

Studies on Enantioselective Effect of Chiral Titanate Reagents on the Synthesis of Substituted Benzhydrols

Chiral titanate reagents were prepared for inducing asymmetric syntheses of substituted benzhydrols from Grignard reagents and aldehydes. The solvents, reaction temperature and exchange of reactants by crossing experiments were investigated. Favorable attack of the nucleophile upon the aromatic aldehydes' prochiral face was proposed, the absolute configurations of the synthesized benzhydrols were suggested, and a preliminary reaction mechanism was described.

Synthesis and Phase Behavior Studies of Two New Chiral Liquid Crystals of Schiff Base——The Influence of Intramolecular Hydrogen Bond on the Phase Behavior

Two new chiral liquid crystals of schiff-base type have been synthesized.This series of compounds contain α-chloro acidic ester chain prepared from commercially available L-valine.Both of the compounds exhibit tilted smectic phases;their phase transitions were studied using DSC and polarized optical microscopy;the influence of intramolecular hydrogen bonds on the phase behavior was studied as well.

SYNTHESIS AND CHARACTERIZATION OF NOVEL CHIRAL SMECTIC C(Sc~*) PHASE SHISH-KEBAB TYPE LIQUID CRYSTALLINE BLOCK COPOLYMERS

A new series of chiral shish-kebab type liquid crystal block copolymers that form the smectic C(Sc*) phase was synthesized by solution polycondensation. The copolymers were characterized by GPC, DSC, TG, POM, X-ray diffraction and polarimeter. The copolymers 7 entered into liquid crystal phase whin they were heated to their melting temperatures (T-m) and the copolymers 8 were in liquid crystal phase at room temperature with low viscosities. The smectic sanded texture or focal-conic texture were observed on POM. All the chiral block copolymers showed high optical activity. No racemization has happened. Temperature-variable X-ray diffraction study together with POM and polarimetric analysis realized that they are chiral smectic C(Sc*) phase. Thus we offer in this report the first example of shish-kebab type liquid crystal block copolymers that form a chiral smectic C(Sc*) phase. The variation of melting and isotropization temperatures with molecular structure was also discussed.

Synthesis of Chiral Amino Cyclic Phosphoric Acids

Chiral amino cyclic phosphoric acids, 5-amino-2-hydroxy-4-(4-nitrophenyl)-1,3,2-dioxaphosphorinane 2-oxide and 2-hydroxy-4-(4-methylsulfonylphenyl)-5-phthalimido-1,3,2-dioxaphos phorinane 2-oxide are synthesized in good over yields (64.2%and 72.8%respectively) from 2-amino-1-aryl-1,3-propanediols. The different reaction conditions are necessary in hydrolysis reactions of amino cyclic phosphonyl chlorides.

Synthesis and Characterization of Both Enantiomers of a Chiral C_(60) Derivative Bearing the 1, 1'-Binaphthyl Group

Both enantiomers R-1 and S-1 of a chiral C60 derivative were synthesized by the reactions of C60 with 1, 1'-bi-2-naphthol bis(azidoacetates) and characterized by FD-MS, fT-IR,1H NMR, 13C NMR, UV-VIS, CD spectra.

Reductive amination of ketones with ammonium catalyzed by a newly identified Brevibacterium epidermidis strain for the synthesis of(S)-chiral amines

The asymmetric reductive amination of achiral ketones with ammonia is a particularly attractive reaction for the synthesis of chiral amines.Although several engineered amine dehydrogenases have been developed by protein engineering for the asymmetric reductive amination of ketones,they all display(R)‐stereoselectivity.To date,there is no report of an(S)‐stereoselective biocatalyst for this reaction.Herein,a microorganism named Brevibacterium epidermidis ECU1015 that catalyzes the(S)‐selective reductive amination of ketones with ammonium has been successfully isolated from soil.Using B.epidermidis ECU1015 as the catalyst,the asymmetric reductive amination of a set of phenylacetone derivatives was successfully carried out,yielding the corresponding(S)‐chiral amines with moderate conversion and>99%enantiomeric excess.

Synthesis,Characterization,X-ray Crystal Structure and Safener Activity of Chiral 2-(3-Methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl)-2-oxoethyl Acetate

The new title compound, chiral 2-（3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl）- 2-oxoethyl acetate, has been synthesized via reduction, cyclization and acylation reaction. The structure of the product has been confirmed by IR, 1H NMR, 13C NMR, LC-MS （ESI） and single-crystal X-ray diffraction. （R）-2-（3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl）-2-oxoethyl acetate crystallizes in monoclinic, space group P21/c with a = 11.867（2）, b = 8.4087（2）, c = 14.325（6） A^°, β = 117.59（2）°, Z = 4, V = 1266.9（6） A^°3, Dc = 1.307 g/cm^3, F（000） = 528, μ（MoKα） = 0.097 mm-1, R = 0.0453 and wR = 0.1237; （S）-2-（3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl）-2-oxoethyl acetate belongs to the triclinic system, space group P with a = 8.2647（17）, b = 8.7034（17）, c = 9.5479（19） A^°, α = 105.33（3）, β = 100.95（3）, γ = 105.14（3）°, Z = 2, V = 614.1（2） A^°3, Dc = 1.348 g/cm^3, F（000） = 264, μ（MoKα） = 0.10 mm-1, R = 0.0613 and wR = 0.1037. Both of the molecules prefer to form crystal packing through C–H…O hydrogen bonds.

SYNTHESIS OF DIAZA CROWN ETHER CHIRAL LIQUID CRYSTAL

A chiral liquid crystal crown ether containing diaza-18-crown-6 was synthesized with the help of CPK atomic model and in the meantime a nonchiral liquid crystal crown ether of alike structure was also synthesized for comparison, indicating that only the former was asymmetric. The present work represents the first attempt of the investigation in chiral liquid crystal crown ether, thus providing basis for further research into problems as such.

The Synthesis of New Sulfur-containing Chiral Macrocyclic Ligands

Five new chiral sulfur-containing macrocyclic ligands which can be used in chiral recognition to guests have been synthesized and characterized

Chiral Synthesis of the Intermediate of (-)-Gibberellin A_(12)

(-)-Dimethyl(1R,4aS),4a-dimethyl-6-nitro-1,2, 3,4, 4a-pentahydrofluorene-1, 9 -dicarboxylate (1) was synthesized from (R)-(+)-2 -methyl- 2 -(2 -nitrovinyl)-δ-valerolactone(2),which constitutes a formal total Synthesis of (-)-gibberellin A_(12).

SYNTHESIS OF CHIRAL MIXED-LICAND COMPLEXES AND THEIR USE IN ASYMMETRIC SYNTHESIS OF CHRYSANTHEMIC ACID

Several chiral mixed-ligand complexes have been synthesized and their efficiency as catalysts for the asymmetric synthesis of chrysanthemic acid tested.

Design,synthesis and antifungal activities in vitro of novel tetralin compounds

Novel chiral tetralin compounds were designed and synthesized, and their antifungal activities in vitro were tested. The results showed that all of target compounds had potent antifungal activities, and were stronger than that of control compounds tetrahydroisoquinolines. The binding model of lead molecules in the active site of CYP51 of Candida albicans showed that lead compound specifically interacted with the amino acids residues in the active site, without binding with the heme of CYP51, which was different from azole antifungal drugs. The present study might afford a novel lead molecule to develop non-azole CYP51 inhihitars of fungi.