Alumina → HCID 18704059, compound

Participants

Reaction Conditions

Reaction Steps

0.01 g of ammonium vanadate and 8 g of aluminium oxide granules containing 0.5% by weight of metallic platinum and having a particle size of 3.2 mm (from Acros Organics) are added to a suspension consisting of 200 ml of water and 21.4 g of 5-chloro-6-nitrobenzimidazolone. After displacing the air with nitrogen, the latter is replaced by hydrogen at atmospheric pressure and the suspension is stirred at 65° C. At a hydrogen absorption of 85% of theory, another 50 ml of water are added to improve the stirrability and the mixture is then stirred at the same temperature under a hydrogen atmosphere for a total of 98 hours. During this time, 97% of the theoretical amount of hydrogen, based on 5-chloro-6-nitrobenzimidazolone, is absorbed. The resulting suspension is then sieved through a sieve having a mesh width of 1 mm. The material remaining on the sieve is washed with 50 ml of water and the combined aqueous phases are then filtered through a paper filter and washed with 100 ml of water. Drying at 80° C. under reduced pressure (125 mbar) gives 17.5 g (95%) of 5-amino-6-chlorobenzimidazolone. Only traces of 5-aminobenzimidazolone can be found in the NMR.

Provenance & Evidence