Cesium carbonate → Methyl 4-[(4-ethylphenyl)amino]-5-methylthiothiophene-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

To an oven-dried glass vial with stir bar was added a mixture of 100 mg (0.374 mmol) of methyl 4-bromo-5-methylthiothiophene-2-carboxylate (as prepared in Example 241, step (a)), 5.8 mg (6.9 mol %) of palladium (II) acetate, 21.7 mg (9.3 mol %) of racemic-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, 171.5 mg (0.526 mmol) of cesium carbonate and 59 mg (0.487 mmol) of 4-ethylaniline. The vial was transferred to a glove bag, flushed with dry argon and anhydrous toluene (749 μL) was added. The vial was capped with a Teflon-lined screw cap and heated at 100° C. for 48 h. The cooled suspension was filtered (Celite) washing with ethyl acetate (2×2 mL), and the solvents removed in vacuo. The resulting residue was purified on 1 mm silica prep plates eluting with 40% methylene chloride-hexanes to afford 14 mg (12%) of methyl 4-[(4-ethylphenyl)amino]-5-methylthiothiophene-2-carboxylate as a pale yellow resin which was used directly in the following step.

Provenance & Evidence