- Electrophotochemical Ring-Opening Bromination oftert-Cycloalkanols
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An electrophotochemical ring-opening bromination of unstrainedtert-cycloalkanols has been developed. This electrophotochemical method enables the oxidative transformation of cycloalkanols with 5- to 7-membered rings into synthetically useful ω-bromoketones without the use of chemical oxidants or transition-metal catalysts. Alkoxy radical species would be key intermediates in the present transformation, which generate through homolysis of the O-Br bond in hypobromite intermediates under visible light irradiation.
- Yamamoto, Kosuke,Toguchi, Hiroyuki,Kuriyama, Masami,Watanabe, Shin,Iwasaki, Fumiaki,Onomura, Osamu
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p. 16177 - 16186
(2021/09/13)
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- Synthesis of ketamine from a nontoxic procedure: a new and efficient route
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Abstract: Ketamine [2-(2-chlorophenyl)-2-methylamino-cyclohexan-1-one]has been used in both veterinary and human medicine. In this research, a new and efficient protocol has been developed for the synthesis of ketamine, by using hydroxy ketone intermediate.Synthesis of this drug has been done in five steps. At first, the cyclohexanone was made to react with 2-chlorophenyl magnesium bromide reagent followed by dehydration in the presence of an acidic ionic liquid, 1-methyl-3-[2-(dimethyl-4-sulfobutyl-ammonium) ethane] imidazolium hydrogen sulfate to obtain 1-(2-chlorophenyl)-cyclohexene. The oxidation of the synthesized alkene by potassium permanganate gave corresponding hydroxy ketone intermediate. The imination of this intermediate by methyl amine and finally the rearrangement of the obtained imine at elevated temperature resulted in the synthesis of ketamine. All of the intermediates and the product were characterized by 1H-NMR and IR spectroscopies. No need to use toxic bromine (which is used in most of the reported procedures for the synthesis of ketamine), high reaction yields and use of commercially available and safe materials and no need to use corrosive acids in the dehydration step are some of the advantages of this procedure over the common reported ones for the snthesis of ketamine. Graphic abstract: An efficient five-step protocol for the synthesis of ketamine was developed. Cyclohexanone reacted with 2-chlorophenyl magnesium bromide, followed by dehydration with acidic ionic liquid. Oxidation of the alkene gave corresponding hydroxy ketone intermediate.The imination of this intermediate and rearrangement of the obtained imine finally produced ketamine.[Figure not available: see fulltext.]
- Fareghi-Alamdari, Reza,Momeni-Fard, Behnaz,Zekri, Negar
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- Novel enantioselective synthesis of (S)-ketamine using chiral auxiliary and precursor Mannich base
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Ketamine has been extensively used as an anesthetic drug. Chiral auxiliaries such as tert-butanesulfinamide (TBSA) can be used for the asymmetric synthesis of (S)-ketamine. Condensation of TBSA with ketones provides tert-butanesulfinylimines in consistently high yields. The tert-butanesulfinyl group actuates the imine for nucleophilic addition, is a potent chiral directing group, and after nucleophilic addition is easily dissociated by intervention with acid solution. To prepare 2-(N-piperidinomethyl)-1-phenylcyclohexylamine (1), we started with the cyclohexanone and using Mannich reaction achieved an aminoketone. Then, we made the sulfiniylamin (2) by the condensation of TBSA with aminoketone. By using salts such as Ti(OEt)4, we obtained N-tert-butanesulfinylketimine in 85% yield. Next, we provided a new chiral center (3) using Grignard reagent as nucleophile at -78 °C (80% yield). Finally, after many steps, the (S)-ketamine synthesized under ozonolysis conditions, with good yield and enantioselectivity (75% yield and 75% ee).
- Gohari, Seyed Jamaladdin,Javidan, Abdollah,Moghimi, Abolghasem,Taghizadeh, Mohammad Javad,Iman, Maryam
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p. 331 - 336
(2019/05/07)
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- SOLID ORAL DOSAGE FORMS OF 2R,6R-HYDROXYNORKETAMINE OR DERIVATIVES THEREOF
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This invention relates to solid oral dosage forms of 2R,6R-hydroxynorketamine or prodrugs thereof having Formula Ib, including any pharmaceutically acceptable salt of the foregoing, for use in a therapeutic method for the treatment of a depressive disorder in a patient.
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Page/Page column 38
(2018/01/17)
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