403-42-9

447-43-8

General procedure for the synthesis of hydrated 4-fluorobenzoylformaldehyde from 4-fluoroacetophenone: general method: a mixture of substrate (0.6 mmol) and bromoethylene (2a, 0.06 mmol) in DMSO (1.1 mL) was placed in an open-topped flask and heated in an oil bath (see Table 2 for specific temperatures and reaction times). After completion of the reaction (monitored by TLC), the reaction mixture was diluted with water (11 mL), treated with saturated NaCl solution and extracted with ethyl acetate (5 × 4 mL). Only in case of synthesis of arylglyoxal, the organic layer was additionally washed with Na2CO3 solution (0.12 mmol, dissolved in 2 mL of water), followed by saturated aqueous NaCl solution and dried with anhydrous Na2SO4. The extract was purified by column chromatography (eluent: petroleum ether/ethyl acetate gradient) to give pure product.