196597-78-1Relevant articles and documents
Concise Six-Step Asymmetric Approach to Ramelteon from an Acetophenone Derivative Using Ir, Rh, Cu, and Ni Catalysis
?asar, Zdenko,Cluzeau, Jér?me,Kova?evi?, Miroslav Planinc,Nettekoven, Ulrike
, (2021/10/20)
A concise six-step asymmetric synthesis of nearly enantiomerically pure ramelteon was developed from a monocyclic precursor with a 17% overall yield and a 97% ee in the asymmetric step. The synthetically challenging tricyclic 1,6,7,8-tetrahydro-2H-indeno[5,4-b]furan core of ramelteon was assembled by using Ir-catalyzed O-vinylation and Rh-catalyzed vinyl ether annulation through directed C-H bond activation, while the chirality was introduced with enantioselective reduction of an α,β-unsaturated nitrile moiety under hydrosilylation conditions using a CuII/Walphos type catalyst. The presented methodology represents the shortest synthetic approach to ramelteon.
Preparation method 1, 2, 6, 7 - tetrahydro - 8H - indeno [5, 4 - b] furan -8 - ketone
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, (2021/09/21)
The invention provides a preparation method of 1, 2, 6, 7 - tetrahydro - 8H - indeno [5, 4 - b] furan -8 - ketone, which comprises the following steps of (1) taking compound II as a raw material, adding a halogenating agent and hydrogen peroxide to halogenate to obtain compound III: 3 - X - 4 - hydroxybenzoic acid. (2) The compound III was mixed with 1 - bromo -2 - chloroethane and an alkali metal hydroxide to give compound IV: 3 - X - 4 - (2 - chloroethoxy) phenylpropionic acid. (3) Compound IV was added to nitrobenzene, and an acylation reagent was added to react to give compound V: 3 - X - 4 - (2 - chloroethoxy) phenylpropionyl chloride. (4) To the reaction system, aluminum trichloride was added to react to give compound VI: 4 - X - 1, 2, 6, 7 - tetrahydro - 8H - indeno [5, 4 - b] furan -8 - ketone. (5) Compound VI was added to toluene, and a palladium carbon and sodium acetate aqueous solution were added to catalyze hydrogenation to give compound I: 1, 2, 6, 7 - tetrahydro - 8H - indeno [5, 4 - b] furan -8 - ketone.
A thunder-US for amine preparation method for the synthesis of the key intermediate
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, (2019/10/02)
The invention discloses a synthetic preparation method for a key intermediate of ramelteon 1,2,6,7-tretrahydro-8H-indeno[5,4-b]furan-8-one. According to the preparation method, by taking 2,3-dihydrobenzofuran-4-formaldehyde as an initial raw material, the key intermediate of ramelteon 1,2,6,7-tretrahydro-8H-indeno[5,4-b]furan-8-one is synthesized through Grignard reaction, oxidizing reaction and Nazarov cyclization reaction. The preparation method has the advantages of being high in reaction selectivity, few in side effects, high in total yield and quality, environmental-friendly, simple and convenient in process operation, high in stability and controllability and the like, and is suitable for industrial large-scaled production.
Pharmaceutical preparation containing copolyvidone
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, (2018/11/06)
A stabilized preparation which comprises: a unstable drug in a polyethylene glycol-containing preparation; and a coating agent comprising a copolyvidone instead of polyethylene glycol with which the drug is coated.
A method of preparing intermediates lei Meiti amine
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Paragraph 0063; 0064, (2017/02/24)
The invention relates to a preparation method of a Ramelteon intermediate. The Ramelteon intermediate is prepared by taking 4,5-dibromo-1,2,6,7-tetrahydro-8H-indeno[5,4-b]furan-8-one as a raw material, and then subjecting the raw material to a series of simple reactions so as to obtain the Ramelteon intermediate. The preparation method of the Ramelteon intermediate has the advantages of high yield, high product purity, simple operation, low cost, and suitability for mass production.
PROCESS FOR PREPARING 1,2,6,7-TETRAHYDRO-8H-INDENO[5,4-B]FURAN-8-ONE
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Page/Page column 9, (2011/05/05)
The invention provides a process for preparing 1,2,6,7-tetrahydro-8H-indeno-[5,4-b]furan-8-one (I), said process comprising the steps: (i) subjecting 6-hydroxy-7-allyl-indan-1-one to ozonolysis followed by reduction in the presence of methanol to form 2-methoxy-1,2,6,7-tetrahydro-8H-indeno[5,4-b]furan-8-one; (ii) subjecting 6-hydroxy-7-allyl-indan-1-one to alcohol elimination to form 6,7-dihydro-8H-indeno-[5,4-b]furan-8-one; and (iii) subjecting 6,7-dihydro-8H-indeno-[5,4-b]furan-8-one to hydrogenation to obtain 1,2,6,7-tetrahydro-8H-indeno[5,4-b]furan-8-one.
SYNTHESIS OF 1-(2,3-DIHYDROBENZOFURAN-4-YL)ETHANONE AS INTERMEDIATE IN THE PREPARATION OF RAMELTEON
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Page/Page column 18, (2010/11/03)
The present invention relates in general to the field of organic chemistry and in particular to the preparation of 1-(2,3-dihydrobenzofuran-4-yl)ethanone, an intermediate in preparation of (S)-N-[2-(1,6,7,8-tetrahydro-2H-indeno-[5,4-b]furan-8-yl)ethyl]propionamide, i.e. ramelteon.
SYNTHESIS OF 6,7-DIHYDRO-1H-INDENO[5,4-B]FURAN-8(2H)-ONE AS INTERMEDIATE IN THE PREPARATION OF RAMELTEON
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Page/Page column 12-13, (2010/04/03)
The present invention describes the preparation of 6, 7 -dihydro-1H-indeno[5, 4 -b] furan-8 (2H) -one of formula V, a key intermediate in preparation of ramelteon. The present invention also describes further preceding intermediate compounds useful for the synthesis of 6, 7-dihydro-1H-indeno[5, 4-b] furan-8 (2H) -one.
SYNTHESIS OF (S)-N-[2-(1,6,7,8-TETRAHYDRO-2H-INDENO-[5,4-B]FURAN-8-YL)ETHYL]PROPIONAMIDE
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Page/Page column 16-17; 21-22, (2010/09/03)
The present invention relates in general to the field of organic chemistry and in particular to the preparation of (S)-N-[2-(1,6,7,8-tetrahydro-2H-indeno-[5,4-b]furan-8-yl)ethyl]propionamide, i.e. ramelteon, and analogues thereof.
PROCESS FOR PREPARATION OF (S)-N-[2-(1,6,7,8-TETRAHYDRO-2H-INDENO[5,4-B]FURAN-8-YL)ETHYL] PROPIONAMIDE AND NOVEL INTERMEDIATES THEREOF
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Page/Page column 30, (2010/04/28)
Disclosed herein process for preparation of (S)-Ramelteon and intermediates thereof.