4-bromo-3-methyl-1H-pyrrole-2-carbaldehyde

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

Procedure: Following a general procedure,50 a stirred suspension of 60% NaH (2.5 g, 62 mmol) in dry THF (42 mL, distilled) was cooled to 0° C. under argon. The mixture was treated portionwise with 3 (7.78 g, 41.4 mmol). The mixture was stirred for 30 min at 0° C. before treating all at once with p-toluenesulfonyl chloride (8.00 g, 41.4 mmol). The reaction mixture was stirred at room temperature for 3 h, whereupon water (100 mL) was slowly added to quench the reaction. Ethyl acetate (100 mL) was added, and the organic layer was separated. The organic layer was washed with brine, dried (Na2SO4), and concentrated to a solid. The solid was dried under high vacuum for 2 h. The crude solid material was dissolved in 100 mL hexanes/ethyl acetate (5:1) by refluxing in a hot water bath. Upon allowing the solution to cool to room temperature the product crystallized. The mixture was cooled overnight at −10° C. to promote additional crystallization. The mixture was vacuum-filtered, and the resulting light brown crystals were dried under high vacuum (9.73 g, 69%): mp 152-155° C.; 1H NMR δ 2.29 (s, 3H), 2.43 (s, 3H), 7.34 (d, J=8.5 Hz, 2H), 7.55 (s, 1H), 7.76 (d, J=8.5 Hz, 2H), 10.14 (s, 1H); 13C NMR δ 2.1, 22.0, 106.2, 126.8, 127.6, 129.1, 130.6, 135.2, 136.4, 146.5, 180.1; Anal. Calcd for C13H12BrNO3S: C, 45.63; H, 3.53; N, 4.09. Found: C, 45.71; H, 3.44; N, 4.11. was slowly added to quench the reaction the organic layer was separated The organic layer was washed with brine dried (Na2SO4) concentrated to a solid The solid was dried under high vacuum for 2 h The crude solid material was dissolved in 100 mL hexanes/ethyl acetate (5:1) by refluxing in a hot water bath to cool to room temperature the product crystallized The mixture was cooled overnight at −10° C. crystallization The mixture was vacuum-filtered the resulting light brown crystals were dried under high vacuum (9.73 g, 69%)

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

Procedure: Following a general procedure,50 a stirred suspension of 60% NaH (2.5 g, 62 mmol) in dry THF (42 mL, distilled) was cooled to 0° C. under argon. The mixture was treated portionwise with 3 (7.78 g, 41.4 mmol). The mixture was stirred for 30 min at 0° C. before treating all at once with p-toluenesulfonyl chloride (8.00 g, 41.4 mmol). The reaction mixture was stirred at room temperature for 3 h, whereupon water (100 mL) was slowly added to quench the reaction. Ethyl acetate (100 mL) was added, and the organic layer was separated. The organic layer was washed with brine, dried (Na2SO4), and concentrated to a solid. The solid was dried under high vacuum for 2 h. The crude solid material was dissolved in 100 mL hexanes/ethyl acetate (5:1) by refluxing in a hot water bath. Upon allowing the solution to cool to room temperature the product crystallized. The mixture was cooled overnight at −10° C. to promote additional crystallization. The mixture was vacuum-filtered, and the resulting light brown crystals were dried under high vacuum (9.73 g, 69%): mp 152-155° C.; 1H NMR δ 2.29 (s, 3H), 2.43 (s, 3H), 7.34 (d, J=8.5 Hz, 2H), 7.55 (s, 1H), 7.76 (d, J=8.5 Hz, 2H), 10.14 (s, 1H); 13C NMR δ 2.1, 22.0, 106.2, 126.8, 127.6, 129.1, 130.6, 135.2, 136.4, 146.5, 180.1; Anal. Calcd for C13H12BrNO3S: C, 45.63; H, 3.53; N, 4.09. Found: C, 45.71; H, 3.44; N, 4.11. was slowly added to quench the reaction the organic layer was separated The organic layer was washed with brine dried (Na2SO4) concentrated to a solid The solid was dried under high vacuum for 2 h The crude solid material was dissolved in 100 mL hexanes/ethyl acetate (5:1) by refluxing in a hot water bath to cool to room temperature the product crystallized The mixture was cooled overnight at −10° C. crystallization The mixture was vacuum-filtered the resulting light brown crystals were dried under high vacuum (9.73 g, 69%)

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

Procedure: Following a general procedure,50 a stirred solution of 3-methyl-pyrrole-2-carboxaldehyde (2, 5.63 g, 51.6 mmol) in THF (52 mL) was cooled to 0° C. NBS (9.19 g, 51.6 mmol; reagent grade, unrecrystallized) was added all at once. The reaction mixture was stirred for 15 min at 0° C. under argon before the solvent was removed on a rotary evaporator. The resulting solid was dried under high vacuum for 2 h. Water (100 mL, room temperature) was added to the flask and the suspension was filtered (Büchner funnel). The filter cake was washed with an additional 100 mL of water. The solid filtered material was recrystallized from water/ethanol as follows. The solid filtered material was transferred to a 250 mL round bottom flask equipped with a reflux condenser. Water/ethanol (150 mL, 5:1) were added and the mixture was refluxed in a hot water bath until all solid material had dissolved. Upon allowing the solution to cool to room temperature the product crystallized. The mixture was cooled to 4° C. for 2 h to promote more crystallization. The mixture was vacuum-filtered and the resulting off-white crystals were dried under high vacuum for 24 h (7.78 g, 80%): mp 140-143° C.; 1H NMR δ 2.32 (s, 3H), 7.08 (d, J=3.3 Hz, 1H), 9.60 (s, 1H), 9.95 (brs, 1H); 13C NMR δ 9.8, 101.7, 126.0, 129.3, 131.7, 177.9; ESI-MS obsd 187.9708, calcd 187.9706 [(M+H)+, M=C6H6BrNO]. was removed on a rotary evaporator The resulting solid was dried under high vacuum for 2 h Water (100 mL, room temperature) was added to the flask the suspension was filtered (Büchner funnel) The filter cake was washed with an additional 100 mL of water The solid filtered material was recrystallized from water/ethanol The solid filtered material was transferred to a 250 mL round bottom flask equipped with a reflux condenser Water/ethanol (150 mL, 5:1) were added the mixture was refluxed in a hot water bath until all solid material had dissolved to cool to room temperature the product crystallized The mixture was cooled to 4° C. for 2 h crystallization The mixture was vacuum-filtered the resulting off-white crystals were dried under high vacuum for 24 h (7.78 g, 80%)

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

Procedure: Following a general procedure,50 a stirred suspension of 60% NaH (2.5 g, 62 mmol) in dry THF (42 mL, distilled) was cooled to 0° C. under argon. The mixture was treated portionwise with 3 (7.78 g, 41.4 mmol). The mixture was stirred for 30 min at 0° C. before treating all at once with p-toluenesulfonyl chloride (8.00 g, 41.4 mmol). The reaction mixture was stirred at room temperature for 3 h, whereupon water (100 mL) was slowly added to quench the reaction. Ethyl acetate (100 mL) was added, and the organic layer was separated. The organic layer was washed with brine, dried (Na2SO4), and concentrated to a solid. The solid was dried under high vacuum for 2 h. The crude solid material was dissolved in 100 mL hexanes/ethyl acetate (5:1) by refluxing in a hot water bath. Upon allowing the solution to cool to room temperature the product crystallized. The mixture was cooled overnight at −10° C. to promote additional crystallization. The mixture was vacuum-filtered, and the resulting light brown crystals were dried under high vacuum (9.73 g, 69%): mp 152-155° C.; 1H NMR δ 2.29 (s, 3H), 2.43 (s, 3H), 7.34 (d, J=8.5 Hz, 2H), 7.55 (s, 1H), 7.76 (d, J=8.5 Hz, 2H), 10.14 (s, 1H); 13C NMR δ 2.1, 22.0, 106.2, 126.8, 127.6, 129.1, 130.6, 135.2, 136.4, 146.5, 180.1; Anal. Calcd for C13H12BrNO3S: C, 45.63; H, 3.53; N, 4.09. Found: C, 45.71; H, 3.44; N, 4.11. was slowly added to quench the reaction the organic layer was separated The organic layer was washed with brine dried (Na2SO4) concentrated to a solid The solid was dried under high vacuum for 2 h The crude solid material was dissolved in 100 mL hexanes/ethyl acetate (5:1) by refluxing in a hot water bath to cool to room temperature the product crystallized The mixture was cooled overnight at −10° C. crystallization The mixture was vacuum-filtered the resulting light brown crystals were dried under high vacuum (9.73 g, 69%)

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

Procedure: Following a general procedure,50 a stirred solution of 3-methyl-pyrrole-2-carboxaldehyde (2, 5.63 g, 51.6 mmol) in THF (52 mL) was cooled to 0° C. NBS (9.19 g, 51.6 mmol; reagent grade, unrecrystallized) was added all at once. The reaction mixture was stirred for 15 min at 0° C. under argon before the solvent was removed on a rotary evaporator. The resulting solid was dried under high vacuum for 2 h. Water (100 mL, room temperature) was added to the flask and the suspension was filtered (Büchner funnel). The filter cake was washed with an additional 100 mL of water. The solid filtered material was recrystallized from water/ethanol as follows. The solid filtered material was transferred to a 250 mL round bottom flask equipped with a reflux condenser. Water/ethanol (150 mL, 5:1) were added and the mixture was refluxed in a hot water bath until all solid material had dissolved. Upon allowing the solution to cool to room temperature the product crystallized. The mixture was cooled to 4° C. for 2 h to promote more crystallization. The mixture was vacuum-filtered and the resulting off-white crystals were dried under high vacuum for 24 h (7.78 g, 80%): mp 140-143° C.; 1H NMR δ 2.32 (s, 3H), 7.08 (d, J=3.3 Hz, 1H), 9.60 (s, 1H), 9.95 (brs, 1H); 13C NMR δ 9.8, 101.7, 126.0, 129.3, 131.7, 177.9; ESI-MS obsd 187.9708, calcd 187.9706 [(M+H)+, M=C6H6BrNO]. was removed on a rotary evaporator The resulting solid was dried under high vacuum for 2 h Water (100 mL, room temperature) was added to the flask the suspension was filtered (Büchner funnel) The filter cake was washed with an additional 100 mL of water The solid filtered material was recrystallized from water/ethanol The solid filtered material was transferred to a 250 mL round bottom flask equipped with a reflux condenser Water/ethanol (150 mL, 5:1) were added the mixture was refluxed in a hot water bath until all solid material had dissolved to cool to room temperature the product crystallized The mixture was cooled to 4° C. for 2 h crystallization The mixture was vacuum-filtered the resulting off-white crystals were dried under high vacuum for 24 h (7.78 g, 80%)