Stereoselective Synthesis of （R）-Salmeterol via Asymmetric Cyanohydrin Reaction

The authors described a short and highly enantioselective route to （R）-salmeterol involving asymmetric synthesis of cyanohydrin followed by nucleophilic substitution with 6-（4-phenylbutoxy） hexyl methanesulfonate.     

Synthesis and Crystal Structure of 4-Chloro-N- （2-（2-nitrophenyl）acetoxy）-N-（m-tolyl）benzamide

The new title compound 4-chloro-N-(2-(2-nitrophenyl)acetoxy)-N-(m-tolyl)benzamide(C22H17ClN2O5, Mr = 424.82) has been synthesized via the reaction of 4-chloro-N-hydroxy-N-(m-tolyl)benzamide with 2-(2-nitrophenyl)acetyl chloride. The structure of the product was confirmed by 1H NMR, 13 C NMR, IR, HRMS(ESI) and single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic system, space group P21/c with a = 13.0269(10), b = 6.7251(6), c = 23.9313(16) , β = 99.931(6)o, V = 2065.1(3) 3, Z = 4, Dc = 1.366 g/cm3, F(000) = 880, μ = 0.221 mm-1, the final R = 0.0600 and wR = 0.1754 for 1981 observed reflections(I 2σ(I)). X-ray analysis indicates that the chloro-phenyl ring(C(10)~C(15)) and the methyl-substituted benzene ring(C(16)~C(21)) are not coplanar with the nitro-substituted benzene ring(C(1)~C(6)), with the dihedral angle to be 70.78° and 63.72°, respectively. Hydrogen bonds C(2)–H(2)···O(2) and C(7)–H(7B)···O(5) are observed.     

One-pot Synthesis of 4-Trifluoromethyl-l,2-dihydropyrimidines

4-Trifluoromethyl-1,2-dihydropyrimidines were synthesized in moderate yields by the one-pot reaction of 4-ethoxy-1,1,1-trifluoro-3-buten-2-one, aldehydes and ammonia catalyzed by zinc chloride under mild conditions.     

Convenient one-pot synthesis of functionalized （E）-2-arylvinyl bromides from （E）-4-（2-bromovinyl）phenyl acetate

A convenient one-pot synthesis of functionalized (E)-2-arylvinyl bromides was achieved by microwave-induced deacetylation and subsequent acylation using dicyclohexyl carbodiimide (DCC) and dimethylamino-pyridine (DMAP) at room temperature from (E)-4-(2-bromovinyl)phenyl acetate.     

Enantioselective Synthesis of （＋）-Nuciferal, （＋）-（E）-Nuciferol and （＋）- α -Curcumene by Chiral Hydrogenesterification Reaction

Using chiral hydrogenesterification reaction as the key step, the stereoselective synthesis of ( )-nuciferal 1, ( )-(E)-nuciferol 2 and ( )-α-curcumene 3 has been achieved.     

Highly Efficient One-Pot Synthesis of 2-Arylmethyl N-Substituted Anilines via Yb（OTf）3 Catalyzed Three-Component Reaction

An efficient method has been developed for one-pot three-component coupling reactions of various aldehydes, 1-cyclohexen-2-one, and primary or secondary amines in the presence of a catalytic amount of Yb（OTf）3 under mild conditions to afford the corresponding 2-arylmethyl N-substituted anilines in good yields. In addition, the catalyst was easily recovered and could be reused for at least four cycles without any loss of activity.     

Synthesis and Crystal Structure of （E）-4-（3-oxo-3-（（4- （N-（pyrimidin-2-yl）-sulfamoyl）phenyl）amino）prop- 1-en-l-yl）-l,2-phenylene diacetate Dimethanol

The title compound, (E)-4-(3-oxo-3-((4-(N-(pyrimidin-2-yl)sulfamoyl)-phenyl)ami- no)prop- 1-en- 1-yl)- 1,2-phenylene diacetate dimethanol, was synthesized by the reaction of caffeic acid with sulfadiaz...     

A Novel Method for Synthesis of 2, 3, 4-Trisubstituted Furans

Intermolecular addition-cyclization of 1, 3-dicarbonyl compounds with arylbromoallenes in K2CO3 mediated condition afforded 2, 3, 4-trisubstituted furans in good yield.     

DFT Study on the Origin of the Enantioselectivity of （S）-4-Hydroxylproline-Catalyzed Direct Aldol Reaction between Acetone and 4-Nitrobenzaldehyde

DFT-B3LYP calculations were carried out to study the enantioselectivity of the （S）-4-hydroxylproline-catalyzed direct aldol reaction between acetone and 4-nitrobenzaldehyde. Four transition structures associated with the stereo-controlling step of the reaction have been determined. They are corresponding to the anti and syn arrangements of the methylene moiety related to the carboxylic acid group in enamine intermediate and the si and re attacks to the aldehyde carbonyl carbon. The effect of DMSO solvent on the stereo-controlling step was investigated with polarized continuum model （PCM）. The computed energies of the transition states reveal the moderate enantioselectivity of the reaction.     

An Efficient and Solvent-Free Reaction for Synthesis of Bis（indol-3-yl）methanes Catalyzed by Sulfamic Acid

SA （sulfamic acid） catalyzes the reaction of indole with aldehyde and ketone to afford bis（indol-3-yl）methanes in good to excellent yields under solvent-free condition at ambient temperature.     

Synthesis and Herbicidal Activities of 3-（Substituted phenyl）isoxazole Derivatives

Several novel 3-(substituted phenyl)isoxazole derivatives were prepared from phenyl butan-l,3-dione. Their structures were confirmed by IH NMR, 1R, and CIMS. Preliminary bioassay showed that some of them exhibited good activities toward various weeds.     

Synthesis,Crystal Structure and Herbicidal Activity of N-（4-Methylbenzyl）-4-（3-fluorophenyl）-4-piperidinol Hydrochloride

A novel compound N-（4-methylbenzyl）-4-（3-fluorophenyl）-4-piperidinol hydrochloride has been synthesized and its structure （C19H23ClFNO, Mr = 335.83） was characterized by elemental analysis, IR, ^1H NMR, MS and single-crystal X-ray diffraction analyses. The crystal belongs to the triclinic system, space group P1 with a = 7.2163（6）, b = 10.7905（9）, c = 12.2651（10） A, α = 109.576（2）,β = 98.407（2）,γ= 95.956（2）°, V= 878.14（13）A3, Z = 2, Dc = 1.270 g/cm^3,μ = 0.231 mm^-1, F（000） = 356, S = 1.100, the final R = 0.0525 and wR = 0.1425 for 3206 unique reflections （Rint = 0.0140） with 2736 observed ones （I 〉 2σ（I））. The piperidine ring exhibits a chair conformation. The dihedral angle made by the methyl- and fluoro-substituted benzene rings is 66.84（7）°. There are some intra- and intermolecular hydrogen bonding interactions among the molecules, which stabilize the whole crystal structure. The preliminary biological activity tests indicate good herbicidal activity for the title compound, in particular against the roots of some tested plants （such as Brassica campestris L. and Echinochloa crusgallis L.）.     

One-pot Copper Nanoparticle-catalyzed Synthesis of Imidazo[1,2-α]pyridines Under Solvent-free Conditions

A direct and efficient approach to synthesize imidazo[1,2-α]pyridines through three-component one-pot reaction of 2-aminopyridine,aldehyde and terminal alkyne catalyzed by Cu-nanoparticles under solvent-free conditions has been developed.This method provides a rapid access to substituted imidazo[1,2-α]pyridines with good yields（up to 85％）.     

Reduced Species （HSO2^-, SO2^·-） Promoted One-Pot Efficient Synthesis of Phenyl Alkyl Selenides

Reduced species （HSO2^-, SO2^·-） promoted one-pot synthesis of phenyl alkyl selenides has been developed. This synthetic method was achieved by reactions of diphenyl diselenide with alkyl halides at room temperature. It is noteworthy that the reactions were operated under mild reaction conditions, required short time, and got good resuits. A single electron transfer reaction mechanism was proposed for the reaction.     

Synthesis and Crystal Structure of（S）-N-（hexahydro-2-oxo-1H-azepin-3-yl）-3-phenyl-2-propenamide

The title compound(S)-N-(hexahydro-2-oxo-1H-azepin-3-yl)-3-phenyl-2-propenamide(C15H18N2O2, Mr = 258.31) was synthesized by the reaction of(S)-α-amino-ε-caprolactam with 3-phenyl-2- propenoyl chloride. Its chemical structure was determined by 1H NMR, 13C NMR, H RMS and X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P21/n with a = 14.957(3), b = 4.884(1), c = 18.630(4), β = 95.91(3)o, V = 1353.7(5)3, Z = 4, Dc = 1.267 g/cm3, μ = 0.085 mm-1, F(000) = 552, R = 0.0671 and wR = 0.1547 for 2473 observed reflections with I 2σ(I).     

Stereoselective Synthesis of （E）-1, 3-Enynyl Bromides via Pd／Cu-cata-lyzed Cross-coupling Reaction of （Z）-α-Bromovinylstannanes

(Z)-α-Bromovinylstannanes undergo the cross-coupling reaction with alkynyl iodides in the presence of Pd(PPh3)4 and CuI in THF at room temperature to afford stereoselectively (E)- 1, 3-enynyl bromides in good yields.     

Facile Synthesis of Enantiomerically Pure 1-（5-Bromo-2-chlorophenyl）-1-（4-ethoxyphenyl）ethane

A facile 7-step procedure for the synthesis of enantiomerically pure 1-（5-bromo-2-chlorophenyl）-1-（4-ethoxyphenyl）ethanes[（R）-2 and（S）-2] that started from （5-bromo-2-chlorophenyl）（4-ethoxyphenyl）methanone 3 was developed.The key step was the resolution of 2-（5-bromo-2-chlorophenyl）-2-（4-ethoxyphenyl）acetic acid 6 by crystallizations of its L-and D-menthyl esters 7 and 8 from petroleum ether to give optically pure enantiomers 9 and 10,respectively.The absolute configurations of the products were unambiguously determined by single-crystal X-ray diffractions of four key intermediates,9,10,13 and 14.This procedure is characterized by inexpensiveness,scalability and ability to produce two individual enantiomers of a diarylethane with unambiguously determined absolute configurations and high enantiomeric purities.     

（E）-α-Bromovinylselenides as Convenient Precursors for Stereose-lective Synthesis of Trisubstituted Alkenes

Based on the different reactivity of selanyl and bromo groups,(E)-α-bromovinylselenides can undergo sequential cross coupling reactions with nucleophiles in the presence of transition metal complexes to form two carbon-carbon bonds in the same olefinic carbon leading to trisubstituted alkenes stereoselectively in good yields.     

One-pot Synthesis of 3-Aryl-1,5-bis（2-hydroxyaryl）pentane-1,5-diones

A simple method for the synthesis of 3-aryl-1,5-bis(2-hydroxyaryl)pentane-1,5-diones is developed by one-potreaction involving 2-hydroxyacetophenone and arylaldehyde in aqueous potassium hydroxide.     

Synthesis, Crystal Structure and Antitumor Activity of 6,7,8-Trimethoxy-1-（4-methoxy-3-nitrophenyl）-4- （pyridin-4-ylmethyl）-3,4-dihydroisoquinoline

A novel class of 3,4-dihydroisoquinolines (7a～e) was designed, synthesized and characterized by IR, NMR and ESI-MS. The crystal structure of compound 7a (6,7,8-trime- thoxy-1-(4-methoxy-3-nitrophenyl)-4-(pyridin-4-methyl)-3,4-dihydroisoquinoline, C25H25N3O6, Mr=463.48) was determined by X-ray diffraction analysis. The crystal belongs to the monoclinic system, space group P21/n with a=12.074(5), b=12.896(6), c=15.450(7), β=105.846(5)°, V=2314.4(17) 3, Z=4, Dc=1.330 Mg/m3, μ(MoKα)=0.096 mm-1, F(000)=976, S=0.991, the final R=0.0467 and wR=0.1231 for 4545 unique reflections (Rint=0.0656) with 3117 observed ones. The bioassay showed that compounds 7a～e exhibit moderate antitumor activities in vitro.