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ChemicalBook CAS DataBase List 7-bromochroman-4-one
18442-22-3

7-bromochroman-4-one synthesis

11synthesis methods
7-Bromochroman-4-one was synthesized by hydrogenation addition of 7-Bromo-benzopyrone catalyzed by Wilkinson's catalyst Rhodium( Ⅰ) tris( triphenylphosphine) chloride[Rh( PPh3)3Cl]. The structure was confirmed by1 H NMR and MS. The optimum reaction conditions for synthesizing 7-Bromochroman-4-one were as follows: 5 0. 329 mol,ethanol as the solvent,c( 5) =0. 4 mol·L- 1,4% mol Rh( PPh3)3Cl as the catalyst,under 0. 3 MPa of hydrogen pressure,at 70℃ for 20 h,the yield was 79. 8%.
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Yield:18442-22-3 85%

Reaction Conditions:

with acid activated montmorillonite K-10 in toluene; for 0.5 h;Reflux;Inert atmosphere;

Steps:

General experimental procedure for the synthesis of chroman-4-one (4a-4p)

General procedure: A mixture of 3-aryloxypropionic acid 3a-3o (1.0 mmol) and freshly prepared AA.Mont.K-10 (300% by weight) in toluene (2 mL) was heated to reflux under inert atmosphere for the specified time (30-45 minutes). After reaction completion, reaction mixture is cooled and added CH2Cl2 (10-15 mL). Filtered the AA.Mont.K-10 and washed twice with CH2Cl2. The organic filtrate is concentrated and the crude mass is extracted with hexane (10-15 mL) to afford pure chromanones 4a-4p.

References:

Begum, Ayisha F.;Balasubramanian, Kalpattu K.;Shanmugasundaram, Bhagavathy [Tetrahedron Letters,2021,vol. 82,art. no. 153372] Location in patent:supporting information

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