Methanesulfonyl chloride → 3-bromo-5-nitro-4-(4-methoxy-3-(6-oxo-3(1H)-pyridazinylmethyl)phenoxy)benzaldehyde

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Reaction Steps

Methane sulphonyl chloride (3.6 g) was added to a solution of 3-bromo-4-hydroxy-5-nitrobenzaldehyde (7.7 g) in dry pyridine (100 ml), and the mixture heated at reflux for 10 min. A solution of 4-methoxy-3-(6-oxo-3(1H)pyridazinylmethyl)phenol (prepared as in Example 44(a)) (6.6 g) in dry pyridine (50 ml) was then added and the resultant dark mixture heated at reflx for 1.5 hours, then allowed to cool to room temperature. The solvent was then evaporated and the residue dissolved in dichloromethane (150 ml), washed with aqueous 2N hydrochloride acid (100 ml), water (100 ml), aqueous saturated sodium bicarbonate solution (2×100 ml) and water (4×100 ml), then dried and evaporated to dryness. The orange residue was dissolved in IMS, treated with charcoal and filtered. On addition of water (200 ml) and cooling a precipitate was formed which was filtered off and dried. This solid was recrystallised from ethyl acetate/petroleum spirit to give 3-bromo-5 -nitro-4-(4-methoxy-3-(6-oxo-3(1H)-pyridazinylmethyl)phenoxy)benzaldehyde (5.2 g, 40%) as a yellow solid, m.p. 188°-190°.

Provenance & Evidence