4-Bromophthalic anhydride

off-white to white powder

A solution of 4-bromophthalic acid (5 g, 0.02 mol) and acetic anhydride (30 mL) was heated for 2 h at 140 °C. The present invention provides a process for the preparation of 4-bromo-phthalic anhydride, First, 11.3 g of sodium hydroxide was dissolved in 50 g of water, 20 g of phthalic anhydride was added and stirred well, followed by the addition of 0.5 g of benzyltrimethylammonium chloride catalyst and stirring was continued.The reaction was then carried out in three stages of temperature control and three times addition of reactants, The first temperature control temperature is 45 , The mass of bromine added was 11.5 g and the reaction time was 1.7 hours.The second paragraph temperature control temperature is 70 , The mass of the added bromine was 10.8 g, Reaction time is 5 hours;The third temperature control temperature is 80 , 3g of sodium hydroxide was added and 10 g of bromine was added thereto to continue the reaction for 5 hours.At the end of the reaction, 15 g of fuming sulfuric acid was added to the product with a mass fraction of 20percentHeating to 96 ° C for acidification, After the acidification was completed, the mixture was cooled to 25 ° C, Then, 15 g of an aqueous solution of sodium bisulfite having a mass fraction of 10percent was added to remove the excess bromine.Ethyl acetate was then added for extraction, After standing for 8 minutes, the organic layer was taken, And the organic layer is distilled to remove the organic solvent, The distillation temperature was 110 ° C, The temperature was then raised to 200 ° C to give crude 4-bromophthalic anhydride.Then 4-bromo-phthalic anhydride in the vacuum of 0.095MPa vacuum distillation under the conditions, And the fractions having a temperature of about 215 ° C were collected, To obtain 4-bromo-phthalic anhydride product.To a solution of intermediate I-53 (22 g, 0.15 mol, 1.0 eq) in water (150 mL) was added solid NaOH (12 g, 0.30 mol, 2.0 eq) and neat BrTo a solution of phthalic anhydride (1) (22 g, 148.5 mmol, 1.0 equiv) in water (150 mL) was added NaOH (12 g, 300.0 mmol, 2.0 equiv) and neat Br2 (8.5 mL, 165.9 mmol, 1.1 equiv) slowly and the mixture was stirred at 90 °C for 12 h. After that the reaction mixture was cooled to 0 °C and filtered to give a light yellow solid. The solid was washed with cold water (50 mL), dissolved in SOd2 (60 mL) and the mixture was heated to reflux for 5 h. The reaction mixture was concentrated to give a residue, to which DCM (200 mL) was added and the mixture was stirred at room temperature for 2 h. The mixture was filtered and the filtrate was concentrated to give 5-bromoisobenzofuran- 1, 3-dione (2) (20 g, 71percent yield) as a yellow solid. 1H-NMR (400 MHz, CDC13) 8.16-8. 17 (m, 1H), 8.06-8.07 (m, 1H), 7. 89-7.90 (m, 1H).General procedure: EXAMPLE 6 Bromoisocyanurate induced radical bromodecarboxylation of (0335) arenecarboxylic acids bromoisocyanurate (0336) ArCO H ArBr (0337) 2 hv (0338) [00139] A mixture of arenecarboxylic acid ArC02H (1 mmol), bromoisocyanurate, additive and solvent (10 mL) was stirred under fluorescent room light (FL) or warm-white 3 W LED (LL) irradiation (hv). The reaction mixture washed with 1 M aq Na2S03, dried over Na2S04, filtered through short neutral alumina pad and concentrated in vacuo to yield crude bromoarene ArBr. Optionally, the crude bromide was purified by chromatography on silica gel. The results are presented in Table 5.Examples of suitable bromo- or chloro-substituted anhydrides include the following non-limiting examples: tetrabromophthalic anhydride, tetrachlorophthalic anhydride, dibromophthalic anhydride, dichlorophthalic anhydride, Typical halogen-containing anhydrides include: 3-chlorophthalic anhydride,

Molecular Weight:227.01
XLogP3:2
Hydrogen Bond Acceptor Count:3
Exact Mass:225.92656
Monoisotopic Mass:225.92656
Topological Polar Surface Area:43.4
Heavy Atom Count:12
Complexity:239
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes