Dimethylformamide → HCID 19773375, compound

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Reaction Steps

0.38 g of a 75% suspension of sodium hydride in paraffin oil (0.012 mol) are added to a mixture of 40 ml of absolute dimethylformamide and 5 ml of absolute tetrahydrofuran. Then 2.88 g (0.010 mol) of 5-acetyl-2-di-n-propylamino-tetraline (Example 4.3.4) dissolved in 10 ml of absolute dimethylformamide are added with stirring and cooling with ice. Then the mixture is stirred at ambient temperature until the reaction is complete (several hours; monitored by DC). After concentration by rotary evaporation, finally at 95° C. under a complete water-jet vacuum, the residue is shaken with 50 ml of water and 50 ml of methylene chloride. The aqueous phase separated off is extracted twice more with 15 ml of methylene chloride. The combined extracts are washed with 20 ml of water, dried with sodium sulphate and, after the drying agent has been filtered off, concentrated by rotary evaporation, finally at 80° C. under a complete water-jet vacuum. The residue cannot be crystallised either as a base or as a salt. Therefore it is purified by column chromatography on 150 g of silica gel with methylene chloride/methanol/conc. ammonia 90:10:0.5. The substance purified in this way (2.8 g, 92.6% of theory) does not crystallise either, even though it is pure according to thin layer chromatography (silica gel, above-mentioned mixture of solvents, Rf =0.64) and by NMR spectroscopy.

Provenance & Evidence