6,7-dichloro-4H-1,4-benzoxazin-3-one

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

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

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 1 L round-bottom flask was purged with argon and charged with sodium hydride (6.94 g of a 60% dispersion of NaH in mineral oil, 0.174 mol) and 60 mL of anhydrous DMF. This suspension was magnetically stirred and cooled to 0° C. in an ice-bath and then treated slowly with a suspension of 6,7-dichloro-2H-1,4-benzoxazin-3(4H)-one (22.2 g. 0.102 mol) in 140 mL of anhydrous DMF. The reaction mixture was maintained at 0° C. for one hour and then treated slowly with ethyl bromoacetate (29.4 mL, 0.265 mol) over a period of 5-10 minutes. This reaction mixture was maintained at 0° C. for thirty minutes, allowed to warm to room temperature, and then was maintained at room temperature for thirty minutes. HPLC (Eclipse XDB-C18, 4.6×250 mm, 5 micron, 1-99% CH3CN/H2O with 0.1% trifluoroacetic acid) showed that all of the starting material (Rt=6.2 min) was gone and that a new compound had formed (Rt=7.5 min). The reaction mixture was poured into 5.5 L of 5% aqueous HCl and the product precipitated immediately as a yellow solid. The suspension was stirred for 10 minutes and the solid was filtered off to give a yellow filter cake. The solid was rinsed with ice-cold ethanol (3×200 mL) and hexanes (3×200 mL) and then dried under high vacuum to give ethyl (6,7-dichloro-3-oxo-2,3-dihydro-4H-1,4-benzoxazin-4-yl)acetate (26.0 g, 0.085 mol, 84%) as a white powder. MS (ES) m/e 304 [M+H]+. A 1 L round-bottom flask was purged with argon charged with sodium hydride (6.94 g of a 60% dispersion of NaH in mineral oil, 0.174 mol) and 60 mL of anhydrous DMF The reaction mixture was maintained at 0° C. for one hour This reaction mixture was maintained at 0° C. for thirty minutes to warm to room temperature was maintained at room temperature for thirty minutes had formed (Rt=7.5 min) the product precipitated immediately as a yellow solid The suspension was stirred for 10 minutes the solid was filtered off to give a yellow filter cake The solid was rinsed with ice-cold ethanol (3×200 mL) and hexanes (3×200 mL) dried under high vacuum

Conditions: temp:85.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl[(4,5-dichloro-2-nitrophenyl)oxy]acetate (36.0 g, 0.122 mol) was dissolved in 400 mL of ethanol and treated with SnCl2.2H2O (138.0 g, 0.612 mol). This mixture was magnetically stirred and heated to 85° C. in an oil bath. After stirring overnight, HPLC (Eclipse XDB-C18, 4.6×250 mm, 5 micron, 1-99% CH3CN/H2O with 0.1% trifluoroacetic acid) showed that all of the starting material (Rt=7.8 min) was gone and that two new compounds had formed: the desired product (Rt=6.2 min) and the hydroxamic acid of the desired product (Rt=5.9 min). An additional 138.0 g of SnCl2.2H2O (0.612 mol) and 90 mL of concentrated HCl were added and stirred at 85° C. for seven hours, after which time HPLC showed that only the desired product remained. The reaction mixture was poured into 5.5 L of 5% aqueous HCl and a suspension formed which was stirred for 20 minutes, resulting in a white precipitate. The white solid was filtered off and air-dried on a vacuum funnel for one hour. The white solid was transferred to a 1 L round bottom flask and suspended in 500 mL of absolute ethanol. The solvent was removed by rotary evaporation to azeotrope off the last traces of water. This process of suspending the solid in absolute ethanol and removing the solvent by rotary evaporation was repeated once more. The resulting white solid was dried overnight under high vacuum to give 6,7-dichloro-2H-1,4-benzoxazin-3(4H)-one (22.2 g. 0.102 mol, 83%) as a fine white powder. MS (ES) m/e 218 [M+H]+. After stirring overnight had formed

Conditions: temp:85.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl[(4,5-dichloro-2-nitrophenyl)oxy]acetate (36.0 g, 0.122 mol) was dissolved in 400 mL of ethanol and treated with SnCl2.2H2O (138.0 g, 0.612 mol). This mixture was magnetically stirred and heated to 85° C. in an oil bath. After stirring overnight, HPLC (Eclipse XDB-C18, 4.6×250 mm, 5 micron, 1-99% CH3CN/H2O with 0.1% trifluoroacetic acid) showed that all of the starting material (Rt=7.8 min) was gone and that two new compounds had formed: the desired product (Rt=6.2 min) and the hydroxamic acid of the desired product (Rt=5.9 min). An additional 138.0 g of SnCl2.2H2O (0.612 mol) and 90 mL of concentrated HCl were added and stirred at 85° C. for seven hours, after which time HPLC showed that only the desired product remained. The reaction mixture was poured into 5.5 L of 5% aqueous HCl and a suspension formed which was stirred for 20 minutes, resulting in a white precipitate. The white solid was filtered off and air-dried on a vacuum funnel for one hour. The white solid was transferred to a 1 L round bottom flask and suspended in 500 mL of absolute ethanol. The solvent was removed by rotary evaporation to azeotrope off the last traces of water. This process of suspending the solid in absolute ethanol and removing the solvent by rotary evaporation was repeated once more. The resulting white solid was dried overnight under high vacuum to give 6,7-dichloro-2H-1,4-benzoxazin-3(4H)-one (22.2 g. 0.102 mol, 83%) as a fine white powder. MS (ES) m/e 218 [M+H]+. After stirring overnight had formed

Conditions: temp:85.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl[(4,5-dichloro-2-nitrophenyl)oxy]acetate (36.0 g, 0.122 mol) was dissolved in 400 mL of ethanol and treated with SnCl2.2H2O (138.0 g, 0.612 mol). This mixture was magnetically stirred and heated to 85° C. in an oil bath. After stirring overnight, HPLC (Eclipse XDB-C18, 4.6×250 mm, 5 micron, 1-99% CH3CN/H2O with 0.1% trifluoroacetic acid) showed that all of the starting material (Rt=7.8 min) was gone and that two new compounds had formed: the desired product (Rt=6.2 min) and the hydroxamic acid of the desired product (Rt=5.9 min). An additional 138.0 g of SnCl2.2H2O (0.612 mol) and 90 mL of concentrated HCl were added and stirred at 85° C. for seven hours, after which time HPLC showed that only the desired product remained. The reaction mixture was poured into 5.5 L of 5% aqueous HCl and a suspension formed which was stirred for 20 minutes, resulting in a white precipitate. The white solid was filtered off and air-dried on a vacuum funnel for one hour. The white solid was transferred to a 1 L round bottom flask and suspended in 500 mL of absolute ethanol. The solvent was removed by rotary evaporation to azeotrope off the last traces of water. This process of suspending the solid in absolute ethanol and removing the solvent by rotary evaporation was repeated once more. The resulting white solid was dried overnight under high vacuum to give 6,7-dichloro-2H-1,4-benzoxazin-3(4H)-one (22.2 g. 0.102 mol, 83%) as a fine white powder. MS (ES) m/e 218 [M+H]+. After stirring overnight had formed

Conditions: temp:85.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl[(4,5-dichloro-2-nitrophenyl)oxy]acetate (36.0 g, 0.122 mol) was dissolved in 400 mL of ethanol and treated with SnCl2.2H2O (138.0 g, 0.612 mol). This mixture was magnetically stirred and heated to 85° C. in an oil bath. After 20 hours, HPLC (Eclipse XDB-C18, 4.6×250 mm, 5 micron, 1-99% CH3CN/H2O with 0.1% trifluoroacetic acid) showed that all of the starting material (Rt=7.8 min) was gone and that two new compounds had formed: the desired product (Rt=6.2 min) and the hydroxamic acid of the desired product (Rt=5.9 min). An additional 138.0 g of SnCl2.2H2O (0.612 mol) and 90 mL of concentrated HCl were added and stirred at 85° C. for seven hours, after which time HPLC showed that only the desired product remained. The reaction mixture was poured into 5.5 L of 5% aqueous HCl and stirred for 20 minutes, resulting in precipitation of the product. The solid was filtered off and air-dried on a vacuum funnel for one hour. The solid was transferred to a 1 L round bottom flask and suspended in 500 mL of absolute ethanol. The solvent was removed by rotary evaporation to azeotrope off the last traces of water and the resulting white solid was dried under high vacuum to give 6,7-dichloro-2H-1,4-benzoxazin-3(4H)-one (22.2 g. 0.102 mol, 83%) as a fine white powder. MS (ES) m/e 218 [M+H]+. had formed

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 1 L round-bottom flask was purged with argon and charged with sodium hydride (6.94 g of a 60% dispersion of NaH in mineral oil, 0.174 mol) and 60 mL of anhydrous DMF. This suspension was magnetically stirred and cooled to 0° C. in an ice-bath and then treated slowly with a suspension of 6,7-dichloro-2H-1,4-benzoxazin-3(4H)-one (22.2 g. 0.102 mol) in 140 mL of anhydrous DMF. The reaction mixture was maintained at 0° C. for one hour and then treated slowly with ethyl bromoacetate (29.4 mL, 0.265 mol) over a period of 5-10 minutes. This reaction mixture was maintained at 0° C. for thirty minutes, allowed to warm to room temperature, and then was maintained at room temperature for thirty minutes. HPLC (Eclipse XDB-C18, 4.6×250 mm, 5 micron, 1-99% CH3CN/H2O with 0.1% trifluoroacetic acid) showed that all of the starting material (Rt=6.2 min) was gone and that a new compound had formed (Rt=7.5 min). The reaction mixture was poured into 5.5 L of 5% aqueous HCl and the product precipitated immediately as a yellow solid. The suspension was stirred for 10 minutes and the solid was filtered off to give a yellow filter cake. The solid was rinsed with ice-cold ethanol (3×200 mL) and hexanes (3×200 mL) and then dried under high vacuum to give ethyl (6,7-dichloro-3-oxo-2,3-dihydro-4H-1,4-benzoxazin-4-yl)acetate (26.0 g, 0.085 mol, 84%) as a white powder. MS (ES) m/e 304 [M+H]+. A 1 L round-bottom flask was purged with argon charged with sodium hydride (6.94 g of a 60% dispersion of NaH in mineral oil, 0.174 mol) and 60 mL of anhydrous DMF The reaction mixture was maintained at 0° C. for one hour This reaction mixture was maintained at 0° C. for thirty minutes to warm to room temperature was maintained at room temperature for thirty minutes had formed (Rt=7.5 min) the product precipitated immediately as a yellow solid The suspension was stirred for 10 minutes the solid was filtered off to give a yellow filter cake The solid was rinsed with ice-cold ethanol (3×200 mL) and hexanes (3×200 mL) dried under high vacuum

Conditions: temp:85.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl [(4,5-dichloro-2-nitrophenyl)oxy]acetate (36.0 g, 0. 122 mol) was dissolved in 400 mL of ethanol and treated with SnCl2·2H2O (138.0 g, 0.612 mol). This mixture was magnetically stirred and heated to 85° C. in an oil bath. After stirring overnight, HPLC (Eclipse XDB-C18, 4.6×250 mm, 5 micron, 1-99% CH3CN/H2O with 0.1% trifluoroacetic acid) showed that all of the starting material (Rt=7.8 min) was gone and that two new compounds had formed: the desired product (Rt=6.2 min) and the hydroxamic acid of the desired product (Rt=5.9 min). An additional 138.0 g of SnCl2·2H2O (0.612 mol) and 90 mL of concentrated HCl were added and stirred at 85° C. for seven hours, after which time HPLC showed that only the desired product remained. The reaction mixture was poured into 5.5 L of 5% aqueous HCl and a suspension formed which was stirred for 20 minutes, resulting in a white precipitate. The white solid was filtered off and air-dried on a vacuum funnel for one hour. The white solid was transferred to a 1 L round bottom flask and suspended in 500 mL of absolute ethanol. The solvent was removed by rotary evaporation to azeotrope off the last traces of water. This process of suspending the solid in absolute ethanol and removing the solvent by rotary evaporation was repeated once more. The resulting white solid was dried overnight under high vacuum to give 6,7-dichloro-2H-1,4-benzoxazin-3(4H)-one (22.2 g. 0.102 mol, 83%) as a fine white powder. MS (ES) m/e 218 [M+H]+. After stirring overnight had formed

Conditions: temp:85.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl [(4,5-dichloro-2-nitrophenyl)oxy]acetate (36.0 g, 0. 122 mol) was dissolved in 400 mL of ethanol and treated with SnCl2.2H2O (138.0 g, 0.612 mol). This mixture was magnetically stirred and heated to 85° C. in an oil bath. After 20 hours, HPLC (Eclipse XDB-C18, 4.6×250 mm, 5 micron, 1-99% CH3CN/H2O with 0.1% trifluoroacetic acid) showed that all of the starting material (Rt=7.8 min) was gone and that two new compounds had formed: the desired product (Rt=6.2 min) and the hydroxamic acid of the desired product (Rt=5.9 min). An additional 138.0 g of SnCl2.2H2O (0.612 mol) and 90 mL of concentrated HCl were added and stirred at 85° C. for seven hours, after which time HPLC showed that only the desired product remained. The reaction mixture was poured into 5.5 L of 5% aqueous HCl and stirred for 20 minutes, resulting in precipitation of the product. The solid was filtered off and air-dried on a vacuum funnel for one hour. The solid was transferred to a 1 L round bottom flask and suspended in 500 mL of absolute ethanol. The solvent was removed by rotary evaporation to azeotrope off the last traces of water and the resulting white solid was dried under high vacuum to give 6,7-dichloro-2H-1,4-benzoxazin-3(4H)-one (22.2 g. 0.102 mol, 83%) as a fine white powder. MS (ES) m/e 218 [M+H]+. had formed