Common use of Palladium Clause in Contracts

Palladium. charcoal (5%) until the absorption of hydrogen had ceased. The catalyst was filtered off and the filtrate evaporated to dryness. The residue was taken up in 5 ml. 2N hydrochloric acid, cooled to -5 degrees C. and treated with 2.5 ml. of 10% aqueous sodium nitrite solution. After standing for 30 minutes, the clear solution was added at -5 degrees C. to a solution of 0.5 g. salicylic acid in 20 ml. of a 1N aqueous sodium hydroxide solution. After subsequently standing for 3 hours at 20 degrees C., the reaction mixture was acidified and extracted with diethyl ether to remove unreacted salicylic acid. The aqueous phase was adjusted to pH 7 by adding 1N aqueous sodium hydroxide solution and the resulting solution was evaporated to dryness. The residue was further dried by adding toluene and subsequently evaporating it and the residue then extracted with methanol. The methanolic solution was concentrated to a small volume. After adding diethyl ether and cooling, the disodium salt of 5-(4-(a- dimethylaminocarboxypentylcarbamoyl)-phenylazo]-salicylic acid separated out; m.p. (greater than) 210 degrees C. (decomp.).

Palladium. charcoal (5%) until the absorption of hydrogen had ceased. The catalyst was filtered off and the filtrate evaporated to drynessdry-ness. The residue was taken up in 5 ml. 2N hydrochloric acid, cooled to -5 degrees -5deg.C. and treated with 2.5 ml. of 10% aqueous sodium nitrite solution. After standing for 30 minutes, the clear solution was added at -5 degrees -5deg.C. to a solution of 0.5 g. salicylic acid in 20 ml. of a 1N aqueous sodium hydroxide solution. After subsequently standing for 3 hours at 20 degrees 20deg.C., the reaction mixture was acidified and extracted with diethyl ether to remove unreacted salicylic acid. The aqueous phase was adjusted to pH 7 by adding 1N IN aqueous sodium hydroxide solution and the resulting solution was evaporated to dryness. The residue was further dried by adding toluene and subsequently evaporating it and the residue then extracted with methanol. The methanolic solution was concentrated to a small volume. After adding diethyl ether and cooling, the disodium salt of 5-(4-(a- 5-[4-(a-dimethylaminocarboxypentylcarbamoyl)-phenylazo]-salicylic acid separated out; m.p. (greater than) 210 degrees 210deg.C. (decomp.).