Sodium hydride → Ammonia

Participants

Reaction Steps

2.88 g (0.06 mol) of sodium hydride dispersion (approximately 50% in oil; Fluka, Buchs, Switzerland) are added in portions over a period of 10 minutes, with stirring and with the introduction of nitrogen, to a solution of 8.1 g (0.05 mol) of benzaldehyde guanylhydrazone in 80 ml of DMF. After 25 minutes stirring at room temperature, 7.1 ml (0.06 mol) of bromoacetaldehyde dimethylacetal (Aldrich, Buchs, Switzerland; 97%, Cat. no. 24,250-0) are added dropwise to the mixture, which has been cooled in an ice-bath. The reaction mixture is stirred for one hour at room temperature and for 20 hours at 55° C., and then concentration by evaporation is carried out in vacuo and the residue is partitioned between ethyl acetate and water. The organic phase is washed with water and brine and is concentrated by evaporation, and the oily residue is purified by flash chromatography on silica gel having a particle size of 0.04-0.063 mm, using ethyl acetate and ethyl acetate/methanol (9:1). Concentration of the product-containing fractions by evaporation yields the title compound in the form of an oil, Rf value=0.80 (silica gel/methylene chloride:methanol:conc. ammonia (40:10:1)), 1H-NMR (DMSO): δ=8.07 (s, 1H); 7.67-7.73 (m, 2H); 7.23-7.40 (m, 3H); 5.93 (bs, 3H); 4.48 (t, 1H); 3.32 (s, 6H); 3.29 (d, 2H).

Provenance & Evidence