Potassium Hydroxide → 5-formyl-4-methyl-1H-pyrrole-2-carboxylic Acid

HRID 397378Notes

Reaction equation

C([O:3][C:4]([C:6]1[NH:7][C:8]([CH:12]=[O:13])=[C:9]([CH3:11])[CH:10]=1)=[O:5])C.[OH-].[K+]>O.C(O)C>[CH:12]([C:8]1[NH:7][C:6]([C:4]([OH:5])=[O:3])=[CH:10][C:9]=1[CH3:11])=[O:13]

Participants

Conditions

Temperature: 100 °C

Procedure

To a solution of 0.8 g (4.4 mmol) of 5-formyl-4-methyl-1H-pyrrole-2-carboxylic acid ethyl ester in 35 mL of water and 15 mL of ethanol was added 0.5 g (8.9 mmol) of potassium hydroxide. The reaction mixture was heated to 100 ° C. for 1 hour, cooled to room temperature, and evaporated ethanol. The water layer was acidified to pH=3 using 2N hydrogen chloride solution. The precipitate was filtered and washed with water to afford 0.67 g (68%) of 5-formyl-4-methyl-1H-pyrrole-2-carboxylic acid as a tan solid. 1H NMR (360 MHz, DMSO-d6) δ 12.92 (br s, 1H, CO2H), 12.48 (br s, 1H, NH), 9.76 (s, 1H, CHO-5), 6.63 (s, 1H), 2.28 (s, 3H, CH3). MS m/z 152 [M−1].

Workup

temperaturecooled to room temperature
customevaporated ethanol
filtrationThe precipitate was filtered
washwashed with water

Sources & evidence

ORD record: ord-068759c7e99d44d3b7a264f658d0fb54
Source dataset: uspto-grants-2003_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06610688B2

Reaction notes

Loading…