Morpholine → (5-Bromo-4-methylthiophen-2-yl)(morpholin-4-yl)methanone

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

5-Bromo-4-methyl-thiophene-2-carboxylic acid methyl ester (8.51 mmol) was dissolved in EtOH (100 ml) and NaOH (42.5 mmol) added, as a 1M solution in water. Reaction was heated to 80° C. for 2 h, after which time all starting material had been consumed. Reaction was then concentrated in vacuo and the residue taken up in DCM and shaken with 1M HCl. The resulting biphasic mixture was then filtered and the filtrant washed with hexane and dried under vacuum. This gave 5-Bromo-4-methyl-thiophene-2-carboxylic acid as off white solid: m/z in MS AP−=219, 221 [M−H]−, 6.79 mmol, 80%. 5-Bromo-4-methyl-thiophene-2-carboxylic acid (6.79 mmol) was taken up in 30 ml DMF and morpholine (7.47 mmol), WSC.HCl (7.47 mmol) and HOBt (7.47 mmol) were added. Reaction was stirred at room temperature for 17 h and then diluted with EtOAc, washed with 1M HCl and brine, dried over Na2SO4 and concentrated in vacuo. Flash chromatography of the residue (silica, 33-50% EtOAc in hexane) gave (5-Bromo-4-methyl-thiophen-2-yl)-morpholin-4-yl-methanone as a pale golden oil: m/z in MS ES+=290, 292 [M+H]+, 4.67 mmol, 69%.

Herkunft & Nachweise