反应详情

55.0 g of a bisazomethine prepared from 2 mols of salicylaldehyde and 1 mol of 2,5-diamino-2,5-dimethylhexane and with a melting point of 111°-112° C. are hydrogenated for 2 hours in 250 ml of ethanol in an autoclave in the presence of 5.5 g of Raney nickel at 100° C. and under a pressure of 80 atmospheres. The catalyst is filtered off and the filtrate is concentrated. The residue is recrystallised from 220 ml of ispropanol, collected by filtration, washed with n-hexane and dried in vacuo, affording 18.9 g (34% of theory) of N,N'-bis-(2-hydroxybenzyl)-2,5-diamino-2,5-dimethyl-hexane with a melting point of 102°-106° C. Two recrystallisations from a mixture of cyclohexane and ethanol yield 15.2 g of pure product with a melting point of 124°-125° C.

1. filtrationThe catalyst is filtered off
2. concentrationthe filtrate is concentrated
3. customThe residue is recrystallised from 220 ml of ispropanol
4. filtrationcollected by filtration
5. washwashed with n-hexane
6. customdried in vacuo