943126-72-5Relevant academic research and scientific papers
Preparation method of 2-chloro-1-(6-fluoro-3,4-dihydro-2H-1-benzopyran-2-yl)ethanone
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Paragraph 0046-0069, (2018/09/08)
The invention provides a preparation method of 2-chloro-1-(6-fluoro-3,4-dihydro-2H-1-benzopyran-2-yl)ethanone shown as a formula (I). The preparation method comprises the following steps: step (a), preparing an organic zinc reagent (III): enabling zinc powder and a compound shown as a formula (IV) to react in an anhydrous solvent A for 2 to 3h at 50 to 70 DEG C, so as to generate the organic zincreagent (III), wherein in the formula (III) or (IV), X1 is selected from Cl, Br and I and X2 is Cl; step (b), enabling the organic zinc reagent which does not need to be post-treated, and 6-fluoro-2-cyano-3,4-dihydro-2H-1-benzopyran shown as a formula (II) to react in an anhydrous solvent B for 15 to 48h at 0 to 45 DEG C; then quenching the unreacted organic zinc reagent and treating an obtained reaction solution to obtain the 2-chloro-1-(6-fluoro-3,4-dihydro-2H-1-benzopyran-2-yl)ethanone shown as the formula (I). The method provided by the invention has the advantages of simple technology, moderate reaction conditions and high safety and is suitable for industrial production. The formula of step (b) is shown in the description.
Preparation of 6-fluoro -3,4-dihydro -2H-1-benzopyran-2-oxirane improved method
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Paragraph 0050; 0051; 0052, (2016/10/07)
The invention relates to an improvement method for preparing a nebivolol key intermediate, namely 6-fluorin-3,4-dihydro-2H-1-benzopyranyl-2-epoxy ethane. The method comprises the following steps of: (a) condensing a compound (IV) and dihalogenated methane in the presence of an organic metal lithium compound to obtain a compound (II); (b) reducing the compound (II) to obtain a compound (III); and (c) performing cyclization on the compound (III) under alkaline condition to obtain a compound (I). The scheme of the invention has the advantages of readily available raw materials, easiness in operating, greatly increased reaction yield and purity and high contribution to industrial mass production.
METHOD FOR PREPARING NEBIVOLOL
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, (2011/10/12)
The present invention relates to a process for the preparation of nebivolol and, more particularly, to an improved process of synthesizing an alpha-haloketone of formula a key intermediate in the preparation of nebivolol.
PROCESS FOR PREPARING NEBIVOLOL
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Page/Page column 12-13, (2008/06/13)
The present invention relates to a process for the preparation of Nebivolol and, more particularly, to an improved method of synthesizing 6-fluoro chroman epoxides of formula (I) key intermediates in preparing nebivolol.
Process for preparation of racemic Nebivolol
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, (2008/06/13)
A process of making racemic [2S*[R*[R*[R*]]]] and [2R*[S*[S*[S*]]]]-(±)α,α′-[iminobis(methylene)]bis[6-fluoro-3,4-dihydro-2H-1-benzopyran-2-methanol] of the compound of the formula (I) and its pure [2S*[R*[R*[R*]]]]- and [2R*[S*[S*[S*]]]]-enantiomer compo
A process for preparation of racemic nebivolol
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Page/Page column 53-54, (2008/06/13)
A process of making racemic [2S*[R*[R*[R*]]]] and [2R*[S*[S*[S*]]]]-(±)α,α'-[iminobis(methylene)]bis[6-fluoro-3,4-dihydro-2H-1-benzopyran-2-methanol] of the compound of the formula (I) and its pure [2S*[R*[R*[R*]]]]- and [2R*[S*[S*[S*]]]]- enantiomer comp
