carbuterol

Originator

Bronsecur,SK and F,W. Germany,1980

Uses

Carbuterol is a beta-adrenoceptor binding drug.

Uses

Bronchodilator.

Definition

ChEBI: Carbuterol is a member of ureas.

Manufacturing Process

A stirred solution of 40 g (0.41 m) of phosgene in 150 ml of toluene is held at 25°C with a cooling bath while a mixture of 252 g (0.105 m) of 3-amino-4- benzyloxyacetophenone and 220 ml of toluene are added slowly. The mixture is heated to reflux and continued for 30 minutes. Nitrogen is passed through the mixture and then concentrated in vacuo to give a crystalline isocyanate, MP 105°-106°C.
A stirred solution of the isocyanate (28.0 g) in 500 ml of dry benzene is saturated with ammonia. After one hour, the mixture is cooled to give the crystalline 4-benzyloxy-3-ureidoacetophenone, MP 184°-186°C.
To a stirred solution of 5.7 g (0.02 m) of 4-benzyloxy-2-ureidoacetophenone in 100 ml of chloroform is added 32 g (0.02 m) of bromine. The mixture is stirred at room temperature for about 45 minutes and the solution is concentrated in vacuo at 25°-30°C. The amorphous residue (hydrobromide salt of 4-benzyloxy-α-bromo-3-ureidoacetophenone) is dissolved in 80 ml of acetonitrile and 98 g (0.06 m) of N-benzyl-N-t-butylamine is added. The mixture is stirred and refluxed for 1.5 hours, then it is cooled to 0°C in an ice bath. Crystalline N-benzyl-N-t-butylamine hydrobromide is filtered. The filtrate is acidified with ethereal hydrogen chloride. The semicrystalline product is filtered after diluting the mixture with a large excess of ether. Trituration of the product with 60 ml of cold ethanol gives 4-benzyloxy-α-(N-benzyl-N-t_x0002_butylamino)-3-ureidoacetophenone hydrochloride, MP 200°-221°C (decomposition).
A solution of 10.5 g (0.0218 m) of 4-benzyloxy-α-(N-benzyl-N-t-butylamino)-3-ureidoacetophenone hydrochloride in 65 ml of methanol and 25 ml of water is added to a suspension of 1.5 g of 10% palladium-on-carbon in 10 ml of water. The mixture is hydrogenated on the Parr apparatus at room temperature, using an initial pressure of 60 psi of hydrogen. After 4 hours about 80% of the theoretical volume of hydrogen has been absorbed. The mixture is filtered, an additional 1.5 g of 10% palladium-on-carbon is added and the mixture is again hydrogenated on the Parr apparatus under the same conditions. After hydrogenating for an additional 3 hours, the mixture is filtered and the filtrate is concentrated in vacuo. The residue is stripped twice with toluene and crystallized with ether-ethanol to give α-(t-butylaminomethyl)-4-hydroxy-3-ureidobenzyl alcohol hydrochloride, MP 214°- 215°C.

brand name

Bronsecur [as the base].

Therapeutic Function

Bronchodilator

Raw materials

Preparation Products