Triethylamine → Benzo[1,2,5]thiadiazole-4-carboxylic acid methoxy-methyl-amide

Participants

Reaction Steps

A suspension of benzo[1,2,5]thiadiazole-4-carboxylic acid (Intermediate L1) (1.8 g, 9.99 mmol) (commercially available from Maybridge) in benzene (100 mL) was treated with oxalyl chloride (5.1 mL of a 2 M CH2Cl2 solution) and DMF (catalytic amount) at rt for 1 h. The solvent was removed under vacuum and re-suspended in benzene. The mixture was decanted into a flask and concentrated under vacuum. The acid chloride intermediate was dissolved in chloroform (10 mL) and added to a solution of N,O-dimethylhydroxylamine-HCl (1.47 g, 15 mmol) (commercially available from Aldrich) and triethylamine (4 mL, 30 mmol) in chloroform (90 mL) at 0° C. The mixture was stirred at rt for 2 h. The mixture was subjected to a standard aqueous work-up. All solvent was removed under vacuum and the residue was purified by chromatography on silica gel with 50% EtOAc:hexane to give benzo[1,2,5]thiadiazole-4-carboxylic acid methoxy-methyl-amide (Intermediate L2) 2 g (90% over two steps).

Provenance & Evidence