4-(difluoromethoxy)-3,5-dimethoxybenzaldehyde

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

Procedure: Piperidine (110 μL, 1.10 mmol) was added to a suspension of 4-(difluoromethoxy)-3,5-dimethoxybenzaldehyde (200 mg, 1.10 mmol) and 2-[(carboxyacetyl)amino]benzoic acid (233 mg, 1.05 mmol) in toluene (5.0 mL). The reaction flask was fitted with a Dean-Stark apparatus and heated to reflux for 30 min. The reaction was then cooled to rt and the resulting suspension was filtered and washed with toluene. The piperidinium salt was dissolved in MeOH (4 mL) and water (2 mL) and the solution was acidified with 20% aqueous AcOH. The crude product was collected by filtration and recrystallised from EtOH/water and filtered to afford (E)-2-[[4-(difluoromethoxy)-3,5-dimethoxyphenyl)-1-oxo-2-propenyl]amino]benzoic acid (210 mg, 51%) as a pale yellow crystalline solid; mp 211-215° C.; δH (400 MHz, DMSO-d6) 3.87 (s, 6H, OCH3), 6.87 (t, J=75 Hz, 1H, OCHF2), 6.98 (d, J=15.6 Hz, 1H, CH═CHCO), 7.17 (s, 2H, H2′, H6′), 7.18 (t, J4,5=J5,6=8.0 Hz, 1H, H5), 7.61 (d, J=15.6 Hz, 1H, CH═CHCO), 7.62 (t, J3,4=J4,5=8.0 Hz, 1H, H4), 8.00 (d, J5,6=8.0 Hz, 1H, H6), 8.61 (d, J3,4=8.0 Hz, 1H, H3), 11.33 (s, 1H, NH), 13.60 (s, 1H, CO2H); δC (100 MHz, DMSO-d6) 56.4, 105.5, 116.8 117.2 (t, J=259 Hz), 120.4, 122.9, 123.1, 129.6, 131.1, 132.9, 134.0, 140.8, 141.1, 152.6, 163.7, 169.4; νmax 1153, 1113, 1224, 1506, 1593, 1694, 2602, 2946 cm−1. The reaction flask was fitted with a Dean-Stark apparatus heated to reflux for 30 min the resulting suspension was filtered washed with toluene The piperidinium salt was dissolved in MeOH (4 mL) The crude product was collected by filtration recrystallised from EtOH/water filtered

Conditions: temp:67.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Methyl chlorodifluoroacetate (0.58 mL, 5.5 mmol) was added to a suspension of 4-hydroxy-3,4-dimethoxybenzaldehyde (0.50 g, 2.7 mmol) and potassium carbonate (0.76 g, 5.5 mol) in DMF (5.0 mL). The suspension was heated to 65-70° C. for 16 h and the suspension was diluted with water. The aqueous phase was extracted with EtOAc and the combined organic fractions were washed with saturated aqueous NaHCO3, water, brine, dried and concentrated. The crude product was recrystallised from EtOAc/petrol providing 4-(difluoromethoxy)-3,5-dimethoxybenzaldehyde (0.25 g, 39%) as a colourless crystalline solid; mp 113-115° C.; δH (400 MHz, CDCl3) 3.95 (s, 6H, OCH3), 6.65 (t, J=74 Hz, 1H, OCHF2), 7.15 (s, 2H, H2, H6), 9.91 (s, 1H, CHO); δC (100 MHz, CDCl3) δ6.5, 106.3, 116.2 (t, J=256 Hz), 134.1, 153.5, 190.8; νmax 831, 1048, 1099, 1330, 1600, 1699, 2854 cm−1. The aqueous phase was extracted with EtOAc the combined organic fractions were washed with saturated aqueous NaHCO3, water, brine dried concentrated The crude product was recrystallised from EtOAc/petrol

Conditions: temp:67.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Methyl chlorodifluoroacetate (0.58 mL, 5.5 mmol) was added to a suspension of 4-hydroxy-3,4-dimethoxybenzaldehyde (0.50 g, 2.7 mmol) and potassium carbonate (0.76 g, 5.5 mol) in DMF (5.0 mL). The suspension was heated to 65-70° C. for 16 h and the suspension was diluted with water. The aqueous phase was extracted with EtOAc and the combined organic fractions were washed with saturated aqueous NaHCO3, water, brine, dried and concentrated. The crude product was recrystallised from EtOAc/petrol providing 4-(difluoromethoxy)-3,5-dimethoxybenzaldehyde (0.25 g, 39%) as a colourless crystalline solid; mp 113-115° C.; δH (400 MHz, CDCl3) 3.95 (s, 6H, OCH3), 6.65 (t, J=74 Hz, 1H, OCHF2), 7.15 (s, 2H, H2, H6), 9.91 (s, 1H, CHO); δC (100 MHz, CDCl3) δ6.5, 106.3, 116.2 (t, J=256 Hz), 134.1, 153.5, 190.8; νmax 831, 1048, 1099, 1330, 1600, 1699, 2854 cm−1. The aqueous phase was extracted with EtOAc the combined organic fractions were washed with saturated aqueous NaHCO3, water, brine dried concentrated The crude product was recrystallised from EtOAc/petrol

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

Procedure: Piperidine (110 μL, 1.10 mmol) was added to a suspension of 4-(difluoromethoxy)-3,5-dimethoxybenzaldehyde (200 mg, 1.10 mmol) and 2-[(carboxyacetyl)amino]benzoic acid (233 mg, 1.05 mmol) in toluene (5.0 mL). The reaction flask was fitted with a Dean-Stark apparatus and heated to reflux for 30 min. The reaction was then cooled to rt and the resulting suspension was filtered and washed with toluene. The piperidinium salt was dissolved in MeOH (4 mL) and water (2 mL) and the solution was acidified with 20% aqueous AcOH. The crude product was collected by filtration and recrystallised from EtOH/water and filtered to afford (E)-2-[[4-(difluoromethoxy)-3,5-dimethoxyphenyl)-1-oxo-2-propenyl]amino]benzoic acid (210 mg, 51%) as a pale yellow crystalline solid; mp 211-215° C.; δH (400 MHz, DMSO-d6) 3.87 (s, 6H, OCH3), 6.87 (t, J=75 Hz, 1H, OCHF2), 6.98 (d, J=15.6 Hz, 1H, CH═CHCO), 7.17 (s, 2H, H2′, H6′), 7.18 (t, J4,5=J5,6=8.0 Hz, 1H, H5), 7.61 (d, J=15.6 Hz, 1H, CH═CHCO), 7.62 (t, J3,4=J4,5=8.0 Hz, 1H, H4), 8.00 (d, J5,6=8.0 Hz, 1H, H6), 8.61 (d, J3,4=8.0 Hz, 1H, H3), 11.33 (s, 1H, NH), 13.60 (s, 1H, CO2H); δC (100 MHz, DMSO-d6) 56.4, 105.5, 116.8 117.2 (t, J=259 Hz), 120.4, 122.9, 123.1, 129.6, 131.1, 132.9, 134.0, 140.8, 141.1, 152.6, 163.7, 169.4; νmax 1153, 1113, 1224, 1506, 1593, 1694, 2602, 2946 cm−1. The reaction flask was fitted with a Dean-Stark apparatus heated to reflux for 30 min the resulting suspension was filtered washed with toluene The piperidinium salt was dissolved in MeOH (4 mL) The crude product was collected by filtration recrystallised from EtOH/water filtered

Conditions: temp:67.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Methyl chlorodifluoroacetate (0.58 mL, 5.5 mmol) was added to a suspension of 4-hydroxy-3,4-dimethoxybenzaldehyde (0.50 g, 2.7 mmol) and potassium carbonate (0.76 g, 5.5 mol) in DMF (5.0 mL). The suspension was heated to 65-70° C. for 16 h and the suspension was diluted with water. The aqueous phase was extracted with EtOAc and the combined organic fractions were washed with saturated aqueous NaHCO3, water, brine, dried and concentrated. The crude product was recrystallised from EtOAc/petrol providing 4-(difluoromethoxy)-3,5-dimethoxybenzaldehyde (0.25 g, 39%) as a colourless crystalline solid; mp 113-115° C.; δH (400 MHz, CDCl3) 3.95 (s, 6H, OCH3), 6.65 (t, J=74 Hz, 1H, OCHF2), 7.15 (s, 2H, H2, H6), 9.91 (s, 1H, CHO); δC (100 MHz, CDCl3) δ6.5, 106.3, 116.2 (t, J=256 Hz), 134.1, 153.5, 190.8; νmax 831, 1048, 1099, 1330, 1600, 1699, 2854 cm−1. The aqueous phase was extracted with EtOAc the combined organic fractions were washed with saturated aqueous NaHCO3, water, brine dried concentrated The crude product was recrystallised from EtOAc/petrol