2,3-二氢-2-甲基苯并呋喃

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: With efficient stirring, 283 g. (1.77 moles) of bromine are added dropwise at 0°-5° C. to a mixture of 237 g (1.77 moles) of 2,3-dihydro-2-methylbenzo[b]furan, 148.7 g (1.77 moles) of sodium bicarbonate, 500 ml of methylene chloride and 500 ml of water. When the addition of bromine is complete, the mixture is stirred for another 1/2 hour at 20°-25° C. The organic phase is separated, dried over sodium sulfate, concentrated and fractionated in vacuo. Yield: 242 g (66% of theory) of 5-bromo-2,3-dihydro-2-methylbenzo[b]furan and 77 g (15% theory) of 5,7-dibromo-2,3-dihydro-2-methylbenzo[b]furan. The organic phase is separated dried over sodium sulfate concentrated

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: A solution of 215 ml of bromine in 450 ml of methylene chloride is added dropwise over 21/2 hours to an ice-cooled mixture of 562.3 g of 2,3-dihydro-2-methylbenzo[b]furan, 1600 ml of methylene chloride, 1600 ml of water and 352.5 g of sodium bicarbonate. After the mixture has been stirred for another 11/2 hours at the same temperature, the aqueous phase is separated and extracted with two 300 ml portions of methylene chloride. The combined organic phases are washed with 2×250 ml of water, dried over sodium sulfate and concentrated. After removal of all constituents having a boiling point below 99° C. under a pressure of 8 mbar, there are obtained 750.7 g of 5-bromo-2,3-dihydro-2-methylbenzo[b]furan as residue. cooled the aqueous phase is separated extracted with two 300 ml portions of methylene chloride The combined organic phases are washed with 2×250 ml of water dried over sodium sulfate concentrated After removal of all constituents

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: A solution of 215 ml of bromine in 450 ml of methylene chloride is added dropwise over 21/2 hours to an ice-cooled mixture of 562.3 g of 2,3-dihydro-2-methylbenzo[b]furan, 1600 ml of methylene chloride, 1600 ml of water and 352.5 g of sodium bicarbonate. After the mixture has been stirred for another 11/2 hours at the same temperature, the aqueous phase is separated and extracted with two 300 ml portions of methylene chloride. The combined organic phases are washed with 2×250 ml of water, dried over sodium sulfate and concentrated. After removal of all constituents having a boiling point below 99° C. under a pressure of 8 mbar, there are obtained 750.7 g of 5-bromo-2,3-dihydro-2-methylbenzo[b]furan as residue. cooled the aqueous phase is separated extracted with two 300 ml portions of methylene chloride The combined organic phases are washed with 2×250 ml of water dried over sodium sulfate concentrated After removal of all constituents

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: With efficient stirring, 283 g. (1.77 moles) of bromine are added dropwise at 0°-5° C. to a mixture of 237 g (1.77 moles) of 2,3-dihydro-2-methylbenzo[b]furan, 148.7 g (1.77 moles) of sodium bicarbonate, 500 ml of methylene chloride and 500 ml of water. When the addition of bromine is complete, the mixture is stirred for another 1/2 hour at 20°-25° C. The organic phase is separated, dried over sodium sulfate, concentrated and fractionated in vacuo. Yield: 242 g (66% of theory) of 5-bromo-2,3-dihydro-2-methylbenzo[b]furan and 77 g (15% theory) of 5,7-dibromo-2,3-dihydro-2-methylbenzo[b]furan. The organic phase is separated dried over sodium sulfate concentrated

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: A solution of 215 ml of bromine in 450 ml of methylene chloride is added dropwise over 21/2 hours to an ice-cooled mixture of 562.3 g of 2,3-dihydro-2-methylbenzo[b]furan, 1600 ml of methylene chloride, 1600 ml of water and 352.5 g of sodium bicarbonate. After the mixture has been stirred for another 11/2 hours at the same temperature, the aqueous phase is separated and extracted with two 300 ml portions of methylene chloride. The combined organic phases are washed with 2×250 ml of water, dried over sodium sulfate and concentrated. After removal of all constituents having a boiling point below 99° C. under a pressure of 8 mbar, there are obtained 750.7 g of 5-bromo-2,3-dihydro-2-methylbenzo[b]furan as residue. cooled the aqueous phase is separated extracted with two 300 ml portions of methylene chloride The combined organic phases are washed with 2×250 ml of water dried over sodium sulfate concentrated After removal of all constituents

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: A solution of 215 ml of bromine in 450 ml of methylene chloride is added dropwise over 21/2 hours to an ice-cooled mixture of 562.3 g of 2,3-dihydro-2-methylbenzo[b]furan, 1600 ml of methylene chloride, 1600 ml of water and 352.5 g of sodium bicarbonate. After the mixture has been stirred for another 11/2 hours at the same temperature, the aqueous phase is separated and extracted with two 300 ml portions of methylene chloride. The combined organic phases are washed with 2×250 ml of water, dried over sodium sulfate and concentrated. After removal of all constituents having a boiling point below 99° C. under a pressure of 8 mbar, there are obtained 750.7 g of 5-bromo-2,3-dihydro-2-methylbenzo[b]furan as residue. cooled the aqueous phase is separated extracted with two 300 ml portions of methylene chloride The combined organic phases are washed with 2×250 ml of water dried over sodium sulfate concentrated After removal of all constituents