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Huang Z.,University of Sichuan | Wu C.,University of Sichuan | Shang Z.,University of Sichuan | Deng Y.,University of Sichuan | Deng Y.,Key Laboratory of Drug Targeting and Drug Delivery System
Chinese Journal of Organic Chemistry | Year: 2012

A novel process for synthesis of 1,2,6,7-tetrahydro-8H-indeno[5,4-6]furan- 8-one, a key intermediate for preparation of ramelteon, a MT1 and MT2 melatonin receptor selective agonist, was developed. The key intermediate 3-(2,3-dihydro-benzofuran-5-yl)propanoic acid was synthesized by condensation of p-bromophenol with bromoacetaldehyde diethyl acetal in the presence of K2CO3 and Friedel-Crafts reaction to give 5-bromobenzofuran, which was subsequently subjected to Heck coupling reaction with methyl acrylate in the presence of palladium acetate, then catalytic hydrogenation and hydrolysis in one pot reaction. Subsequently, 1,2,6,7-tetrahydro-8H-indeno[5, 4-b]furan-8-one was synthesized from 3-(2,3-dihydrobenzo-furan-5-yl)propanoic acid through bromination, Friedel-Crafts acylation and catalytic hydrogenolysis debromination. The overall yield was about 49.9%. The structures of intermediates and final product were determined by 1H NMR, 13C NMR and HRMS techniques. This method has the advantages of easily available starting materials, simply conducted procedures, relatively high yield and easy purification, and is more suitable for scale-up production.

Chen Q.,Chengdu University of Technology | Chen Q.,University of Sichuan | Chen Q.,Chongqing Medical University | Chen Q.,Key Laboratory of Drug Targeting and Drug Delivery System | And 7 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2011

A simple and sensitive high performance liquid chromatography method with fluorescence detection (HPLC-FD) was described for the determination of aesculin (AL) at low concentrations in rabbit plasma and ocular tissues. After deproteinization by methanol using pazufloxacin mesilate (PM) as an internal standard (I.S.), supernatants were evaporated to dryness at 40 °C under a gentle stream of nitrogen. The residue was reconstituted in mobile phase and a volume of 20 μL was injected into the HPLC for analysis. Analytes were separated on an Ultimate XB-C18 column (250. mm × 4.6. mm i.d., 5 μm particle size) and protected by a ODS guard column (10. mm × 4.0. mm i.d., 5 μm particle size), using acetonitrile-0.1% triethylamine in water (adjusted to pH 3.0 using phosphoric acid) (12:88, v/v) as mobile phase with a flow rate of 1.0. mL/min. The wavelengths of fluorescence detector (FD) were set at 344. nm for excitation and 466. nm for emission. The lower limit of quantitation (LOQ) for AL was 0.80. ng/mL for plasma and vitreous body, 1.59. ng/mL for aqueous humor, and 6.55. ng/g for iris and 1.66. ng/g for retina. The method was used in the study of AL concentrations in plasma and ocular tissues after topical administration of AL eye drops. © 2011.

Huang Z.,University of Sichuan | Sang Z.,University of Sichuan | Cao H.,University of Sichuan | Chao R.,University of Sichuan | And 2 more authors.
Chinese Journal of Organic Chemistry | Year: 2014

The ester bond and amide bond of linezolid were selectively hydrolyzed by using LiOH to afford N-[(2R)-3-[[3-fluoro-4-(4-morpholino)phenyl] amino]-2-hydroxypropyl] acetamide (2) and (2S)-1-amino-3-[[3-fluoro-4-(4-morpholino)-phenyl]-amino]-2-propanol (4) with 78.3% and 86.6% yields respectively, which were the partially hydrolyzed impurity and fully hydrolyzed impurity of the injection of linezolid. The terminal amino group of compound 4 was then protected with tert-butyloxycarbonyl and subjected to N, O-diacetylation. Subsequently, N-[(2S)-3-amino-2-hydroxypropyl]-N-[3-fluoro-4-(4-morpholino)phenyl] acetamide (3) hydrochloride was synthesized by removal of O-acetyl with ammonia/methanol and then deprotection tert-butoxycarbonyl using saturated solution of hydrogen chloride in ether with 62.3% overall yield. © 2014 Chinese Chemical Society & SIOC, CAS.

Gu J.,Key Laboratory of Drug Targeting and Drug Delivery System | Ma C.,Key Laboratory of Drug Targeting and Drug Delivery System | Li Q.-Z.,Key Laboratory of Drug Targeting and Drug Delivery System | Du W.,Key Laboratory of Drug Targeting and Drug Delivery System | And 2 more authors.
Organic Letters | Year: 2014

A stereoselective inverse-electron-demand aza-Diels-Alder cycloaddition process of cyclic 1-aza-1,3-butadienes and α,β-unsaturated aldehydes has been developed via dienamine catalysis. This reaction exhibits excellent β,γ- regioselectivity for enal substrates with substantial structural diversity and broad functionalities, readily producing highly enantioenriched fused piperidine derivatives and enabling efficient sequential construction of complex polycyclic frameworks. © 2014 American Chemical Society.

Xiao Y.-C.,Key Laboratory of Drug Targeting and Drug Delivery System | Yue C.-Z.,Key Laboratory of Drug Targeting and Drug Delivery System | Chen P.-Q.,Key Laboratory of Drug Targeting and Drug Delivery System | Chen Y.-C.,Key Laboratory of Drug Targeting and Drug Delivery System | Chen Y.-C.,Chongqing Medical University
Organic Letters | Year: 2014

An asymmetric dearomatic Diels-Alder protocol for various heteroarenes, such as benzofuran, benzothiophene, or even furan, has been developed via π-system activation. This method involves in situ generation of formal trienamine species embedding a heteroaromatic moiety, and an array of chiral fused frameworks with high molecular complexity and skeletal diversity were efficiently constructed in good to excellent stereoselectivity by the catalysis of a cinchona-based primary amine. © 2014 American Chemical Society.

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