3,4-dihydrochromen-2-one

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Diethylamine (98.5 g) and dihydrocoumarin (20.0 g) were refluxed for 4 hours. Excess diethylamine was removed in vacuo to leave 34.0 g of N,N-diethyl-3-(2-hydroxyphenyl) propionamide. 1H NMR (CDCl3): 7.26-7.03 (m, 2H), 6.91 (dd, 1H), 6.81 (td, 1H), 3.37 (quartet, 2H), 3.26 (quartet, 2H), 2.95 (m, 2H), 2.71 (m, 2H), 1.10 (quartet, 6H). Excess diethylamine was removed in vacuo

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 74.08 g (0.50 mole) 2-chromanone in 150 ml carbon disulfide at 0° C. was added dropwise over 15 minutes, 79.91 g (0.50 mole) bromine. Stirring was continued at 0° C. for ten minutes and at room temperature for 2 days. The resulting mixture was filtered, the crystals air dried to afford 96.8 g (85%) of colorless material, m.p. 103°-105° C. (2 crops). The resulting mixture was filtered the crystals air dried

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 74.08 g (0.50 mole) 2-chromanone in 150 ml carbon disulfide at 0° C. was added dropwise over 15 minutes, 79.91 g (0.50 mole) bromine. Stirring was continued at 0° C. for ten minutes and at room temperature for 2 days. The resulting mixture was filtered, the crystals air dried to afford 96.8 g (85%) of colorless material, m.p. 103°-105° C. (2 crops). The resulting mixture was filtered the crystals air dried

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To an ice-cooled solution of methyl magnesium bromide in ether (104 ml × 2.7M; 0.28 mole) was added slowly, under nitrogen, a solution of 13.8 g (0.093 mole) of dihydrocoumarin (Compound 28, Scheme 8) in 230 ml of dry ether. The cooling bath was then removed and the mixture stirred for a further 16 hours. The reaction mixture was then poured onto 300 g of ice and 10 ml of conc. H2SO4 and the mixture was stirred to ensure dissolution. The organic layer was then separated and the aqueous layer was extracted with 2×100 ml of ether. The organic layers were combined and washed successively with 70 ml portions of water, saturated NaHCO3, 2M Na2S2O3 and saturated NaCl and then dried (Na2SO4). The solution was then filtered and the filtrate concentrated in-vacuo to give the title compound as a white solid. PMR (CDCl3) : & 1.30 (6H, s), 1.80 (2H, t, J~7.5 Hz), 2.12 (1H, broad s), 2.73 (2H, t, J~7.5 Hz), 6.80-6.87 (2H, m), 7.00 (1H, broad s), 7.07-7.14 (2H, m). was added slowly, under nitrogen The cooling bath was then removed The reaction mixture was then poured onto 300 g of ice and 10 ml of conc. H2SO4 the mixture was stirred dissolution The organic layer was then separated the aqueous layer was extracted with 2×100 ml of ether washed successively with 70 ml portions of water, saturated NaHCO3, 2M Na2S2O3 and saturated NaCl dried (Na2SO4) The solution was then filtered the filtrate concentrated in-vacuo

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To an ice-cooled solution of methyl magnesium bromide in ether (104 ml × 2.7M; 0.28 mole) was added slowly, under nitrogen, a solution of 13.8 g (0.093 mole) of dihydrocoumarin (Compound 28, Scheme 8) in 230 ml of dry ether. The cooling bath was then removed and the mixture stirred for a further 16 hours. The reaction mixture was then poured onto 300 g of ice and 10 ml of conc. H2SO4 and the mixture was stirred to ensure dissolution. The organic layer was then separated and the aqueous layer was extracted with 2×100 ml of ether. The organic layers were combined and washed successively with 70 ml portions of water, saturated NaHCO3, 2M Na2S2O3 and saturated NaCl and then dried (Na2SO4). The solution was then filtered and the filtrate concentrated in-vacuo to give the title compound as a white solid. PMR (CDCl3) : & 1.30 (6H, s), 1.80 (2H, t, J~7.5 Hz), 2.12 (1H, broad s), 2.73 (2H, t, J~7.5 Hz), 6.80-6.87 (2H, m), 7.00 (1H, broad s), 7.07-7.14 (2H, m). was added slowly, under nitrogen The cooling bath was then removed The reaction mixture was then poured onto 300 g of ice and 10 ml of conc. H2SO4 the mixture was stirred dissolution The organic layer was then separated the aqueous layer was extracted with 2×100 ml of ether washed successively with 70 ml portions of water, saturated NaHCO3, 2M Na2S2O3 and saturated NaCl dried (Na2SO4) The solution was then filtered the filtrate concentrated in-vacuo

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of chroman-2-one (444 mg) in THF (1 mL) was treated with dimethylamine (7.5 mL) and stirred at room temperature for 5 hours. The solution was concentrated. The concentrate was filtered through a small pad of silica gel. The solution was concentrated The concentrate was filtered through a small pad of silica gel