Background and overview[1]
Ketone carbonyl compounds such as m-bromoacetophenone are an important functional group in organic synthesis. This functional group is widely used in the synthesis of fine chemicals and organic synthesis intermediates. For example, acetophenone is widely used in the manufacture of spices, Drugs and other raw materials for organic synthesis, etc. The ketone carbonyl functional group has active chemical properties and is prone to nucleophilic addition reactions with hydrocyanic acid, Grignard reagent, hydroxylamine, alcohol, etc.; it can be reduced to alcohol. Affected by the polarization effect of the carbonyl group, ketones with α-H can undergo halogenation reactions; under alkaline conditions, ketones with methyl groups can undergo many different types of reactions such as haloform reactions. Usually ketone carbonyl groups are prepared by oxidation of secondary alcohols, acylation of aromatic hydrocarbons, and reaction of carboxylic acid derivatives with organometallic compounds.
Preparation[1]
The preparation of m-bromoacetophenone is as follows:
(1) Dissolve ethylbenzene (0.2mmol) m-bromoethylbenzene in 2mL acetonitrile in a 10mL reaction bottle;
(2) Then add magneton, ferric chloride (0.02mmol) and lithium bromide (0.02mmol) respectively, seal the reaction bottle with a stopper, and insert an air ball above the stopper to provide air to the reaction bottle ;
(3) Finally, put the reaction bottle into a 25C incubator and stir the reaction at a distance of 5cm from a 3W blue light (λ=450-455nm). The reaction will be detected by the TLC plate until the reaction is complete (reaction time is about 24 ~58h), spin dry, pass through the column (column chromatography silica gel column), use eluent (first use petroleum ether to elute, and then use petroleum ether/ethyl acetate with a volume ratio of 100/1 to elute) Elute and spin the solvent to dryness to obtain the product acetophenone m-bromoacetophenone. Colorless oil, 78% yield;
HNMR (300MHz, CDCl) δ8.07 (t, =1.7Hz, 1H), 7.86 (d, =7.8Hz, 1H), 7.72–7.64 (m, 1H), 7.34 (t, =7.9Hz, 1H), 2.58 (s, 3H); CNMR (75MHz, CDCl) δ196.6, 138.7, 135.9, 131.3, 130.2, 126.8, 122.9, 26.6.
Main reference materials
[1] CN201610599959.0 A method for preparing ketones by oxidizing the benzylic position
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