1-(2,5-dihydroxyphenyl)propan-1-one

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

Procedure: 6-Hydroxy-3-methyl-2-phenylchroman-4-one was prepared as described for 2-(3-fluorophenyl)-6-hydroxychroman-4-one in Example 9(a) starting from 2.0 g of 2,5-dihydroxypropiophenone and 1.63 ml of benzaldehyde. The product was purified by column chromatography using heptane-ethyl acetate (3:1) as an eluant. 1H NMR (300 MHz, d6-DMSO) δ: 9.37 (s, 1H), 7.53 (m, 2H), 7.47-7.39 (m, 3H), 7.13 (d, 1H, J 3.1 Hz), 7.02 (dd, 1H, J 8.9, 3.1 Hz), 6.89(d, 1H, J 8.9 Hz), 5.17 (d, 1H, J 12.3), 3.18 (dq, 1H, J 12.3, 6.9 Hz), 0.84 (d, 3H, J 6.9 Hz). The product was purified by column chromatography

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

Procedure: 1.6 g of bromine in 6 ml of chloroform are added dropwise to a solution of 4.12 g of 3',5'-dibromo-6,4'-dihydroxy-3-methylflavanone (m.p. 200°-202°; obtainable by reaction of 2,5-dihydroxypropiophenone with 3,5-dibromo-4-hydroxybenzaldehyde in boiling ethanol in the presence of piperidine) in 55 ml of dioxane while stirring and irradiating (500 watt Agaphot lamp). The mixture is stirred for a further 30 minutes while cooling and irradiating, the usual working-up is carried out, and the resulting crude 3,3',5'-tribromo-6,4'-dihydroxy-3-methylflavanone is dissolved in 100 ml of ethanol. 15 ml of 10% aqueous potassium hydroxide solution are added, and the mixture is boiled for 5 minutes, cooled, poured on to ice and the usual working-up is carried out. 3',5'-Dibrom-6,4'-dihydroxy-3-methylflavone ("D") is obtained, m.p. 264°-265°. irradiating (500 watt Agaphot lamp) The mixture is stirred for a further 30 minutes while cooling irradiating cooled poured on to ice

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

Procedure: 1.6 g of bromine in 6 ml of chloroform are added dropwise to a solution of 4.12 g of 3',5'-dibromo-6,4'-dihydroxy-3-methylflavanone (m.p. 200°-202°; obtainable by reaction of 2,5-dihydroxypropiophenone with 3,5-dibromo-4-hydroxybenzaldehyde in boiling ethanol in the presence of piperidine) in 55 ml of dioxane while stirring and irradiating (500 watt Agaphot lamp). The mixture is stirred for a further 30 minutes while cooling and irradiating, the usual working-up is carried out, and the resulting crude 3,3',5'-tribromo-6,4'-dihydroxy-3-methylflavanone is dissolved in 100 ml of ethanol. 15 ml of 10% aqueous potassium hydroxide solution are added, and the mixture is boiled for 5 minutes, cooled, poured on to ice and the usual working-up is carried out. 3',5'-Dibrom-6,4'-dihydroxy-3-methylflavone ("D") is obtained, m.p. 264°-265°. irradiating (500 watt Agaphot lamp) The mixture is stirred for a further 30 minutes while cooling irradiating cooled poured on to ice

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

Procedure: 6-Hydroxy-3-methyl-2-phenylchroman-4-one was prepared as described for 2-(3-fluorophenyl)-6-hydroxychroman-4-one in Example 9(a) starting from 2.0 g of 2,5-dihydroxypropiophenone and 1.63 ml of benzaldehyde. The product was purified by column chromatography using heptane-ethyl acetate (3:1) as an eluant. 1H NMR (300 MHz, d6-DMSO) δ: 9.37 (s, 1H), 7.53 (m, 2H), 7.47-7.39 (m, 3H), 7.13 (d, 1H, J 3.1 Hz), 7.02 (dd, 1H, J 8.9, 3.1 Hz), 6.89(d, 1H, J 8.9 Hz), 5.17 (d, 1H, J 12.3), 3.18 (dq, 1H, J 12.3, 6.9 Hz), 0.84 (d, 3H, J 6.9 Hz). The product was purified by column chromatography

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

Procedure: 6-Hydroxy-3-methyl-2-phenylchroman-4-one was prepared as described for 2-(3-fluorophenyl)-6-hydroxychroman-4-one in Example 9(a) starting from 2.0 g of 2,5-dihydroxypropiophenone and 1.63 ml of benzaldehyde. The product was purified by column chromatography using heptane-ethyl acetate (3:1) as an eluant. 1H NMR (300 MHz, d6-DMSO) δ: 9.37 (s, 1H), 7.53 (m, 2H), 7.47-7.39 (m, 3H), 7.13 (d, 1H, J 3.1 Hz), 7.02 (dd, 1H, J 8.9, 3.1 Hz), 6.89(d, 1H, J 8.9 Hz), 5.17 (d, 1H, J 12.3), 3.18 (dq, 1H, J 12.3, 6.9 Hz), 0.84 (d, 3H, J 6.9 Hz). The product was purified by column chromatography

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

Procedure: 1.6 g of bromine in 6 ml of chloroform are added dropwise to a solution of 4.12 g of 3',5'-dibromo-6,4'-dihydroxy-3-methylflavanone (m.p. 200°-202°; obtainable by reaction of 2,5-dihydroxypropiophenone with 3,5-dibromo-4-hydroxybenzaldehyde in boiling ethanol in the presence of piperidine) in 55 ml of dioxane while stirring and irradiating (500 watt Agaphot lamp). The mixture is stirred for a further 30 minutes while cooling and irradiating, the usual working-up is carried out, and the resulting crude 3,3',5'-tribromo-6,4'-dihydroxy-3-methylflavanone is dissolved in 100 ml of ethanol. 15 ml of 10% aqueous potassium hydroxide solution are added, and the mixture is boiled for 5 minutes, cooled, poured on to ice and the usual working-up is carried out. 3',5'-Dibrom-6,4'-dihydroxy-3-methylflavone ("D") is obtained, m.p. 264°-265°. irradiating (500 watt Agaphot lamp) The mixture is stirred for a further 30 minutes while cooling irradiating cooled poured on to ice

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

Procedure: 1.6 g of bromine in 6 ml of chloroform are added dropwise to a solution of 4.12 g of 3',5'-dibromo-6,4'-dihydroxy-3-methylflavanone (m.p. 200°-202°; obtainable by reaction of 2,5-dihydroxypropiophenone with 3,5-dibromo-4-hydroxybenzaldehyde in boiling ethanol in the presence of piperidine) in 55 ml of dioxane while stirring and irradiating (500 watt Agaphot lamp). The mixture is stirred for a further 30 minutes while cooling and irradiating, the usual working-up is carried out, and the resulting crude 3,3',5'-tribromo-6,4'-dihydroxy-3-methylflavanone is dissolved in 100 ml of ethanol. 15 ml of 10% aqueous potassium hydroxide solution are added, and the mixture is boiled for 5 minutes, cooled, poured on to ice and the usual working-up is carried out. 3',5'-Dibrom-6,4'-dihydroxy-3-methylflavone ("D") is obtained, m.p. 264°-265°. irradiating (500 watt Agaphot lamp) The mixture is stirred for a further 30 minutes while cooling irradiating cooled poured on to ice

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

Procedure: The compound was prepared by a method similar to Example 11 from 2',5'-dihydroxypropiophenone, cyclohexanecarbonyl chloride, 1-bromo-6-chlorohexane, and 4-hydroxypiperidine: mp 109°-110° C.

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

Procedure: The compound was prepared by a method similar to Example 11 from 2',5'-dihydroxypropiophenone, cyclohexanecarbonyl chloride, 1-bromo-6-chlorohexane, and 4-hydroxypiperidine: mp 109°-110° C.

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

Procedure: 1.6 g of bromine in 6 ml of chloroform are added dropwise to a solution of 4.12 g of 3',5'-dibromo-6,4'-dihydroxy-3-methylflavanone (m.p. 200°-202°; obtainable by reaction of 2,5-dihydroxypropiophenone with 3,5-dibromo-4-hydroxybenzaldehyde in boiling ethanol in the presence of piperidine) in 55 ml of dioxane while stirring and irradiating (500 watt Agaphot lamp). The mixture is stirred for a further 30 minutes while cooling and irradiating, the usual working-up is carried out, and the resulting crude 3,3',5'-tribromo-6,4'-dihydroxy-3-methylflavanone is dissolved in 100 ml of ethanol. 15 ml of 10% aqueous potassium hydroxide solution are added, and the mixture is boiled for 5 minutes, cooled, poured on to ice and the usual working-up is carried out. 3',5'-Dibrom-6,4'-dihydroxy-3-methylflavone ("D") is obtained, m.p. 264°-265°. irradiating (500 watt Agaphot lamp) The mixture is stirred for a further 30 minutes while cooling irradiating cooled poured on to ice