7-Methyl-6-chlorochromene → 6-chloro-7-(thien-2-ylmethyl)-2-(trifluoromethyl)-2H-chromene-3-carboxylic acid

Participants

Reaction Steps

The ester obtained from Example 170 Step 3 was converted to the acid according to the procedure of Example 150 Step 4. The product (20 mg) contained a major impurity amounting to 14%, which was determined to be the 7-methyl-6-chlorochromene, which can be removed by reverse phase HPLC (column: Delta Pak 300×50 mm I.D. C18, 15 μM) using a H2O—CH3CN gradient (conditions: 90/10-50/50 over 30 minutes) which gave pure product. 1H NMR (MeOH-d4) 7.54 (s, 1H), 7.14 (s, 1H), 7.07 (d, 1H, J=4.3 Hz), 6.76-6.73 (3H), 5.55 (q, 1H, J=6.9 Hz), 4.15 (d, 1H, J=16.7 Hz), 4.05 (d, 1H, J=16.1 Hz).

Provenance & Evidence