18559-94-9

solid

Ventolin ,Allen and Hanburys ,UK ,1969

In 1968, Salbutamol (Albuterol) will become the most prescribed bronchodilator in the world. Discovered by DAVID HARTLEY, DAVID JACK, LAWRENCE LUNTZ AND ALEXANDER RITCHIE of the British company Allen and Hanburys, former division of Glaxo-smith kline marketed under the name of Ventolin; who will stop the acute crisis and save the life of the asthmatic.
In 2008, a study shows its action in cases of neuromuscular diseases.
In February 2020, the U.S. Food and Drug Administration (FDA) approved the first generic of an albuterol sulfate inhalation aerosol for the treatment or prevention of bronchospasm in people four years of age and older with reversible obstructive airway disease and the prevention of exercise-induced bronchospasm in people four years of age and older. The FDA granted approval of the generic albuterol sulfate inhalation aerosol to Perrigo Pharmaceutical.

Albuterol(18559-94-9) is widely used for severe and chronic bronchial asthma and other illnesses of the respiratory tract that result in a spastic condition of the bronchi.

immune suppressant, antineoplastic, antiviral

short-acting b2-adrenergic agonist, asthma therapeutic

ChEBI: A member of the class of phenylethanolamines that is 4-(2-amino-1-hydroxyethyl)-2-(hydroxymethyl)phenol having a tert-butyl group attached to the nirogen atom. It acts as a beta-adrenergic agonist used in the treatment of asthma and chronic obstructive pulmonary disease (COPD).

(a) α1-Benzyl-tert-butylaminomethyl-4-hydroxym-xylene-α1,α3-diol: 3.0 g of 5-(N-benzyl-N-tert-butylglycyl)-salicylic acid methyl ester hydrochloride in 40 ml of water was basified with sodium bicarbonate solution and extracted into ether. The ethereal solution was dried over MgSO4 and evaporated and the basic residue in 20 ml of dry tetrahydrofuran was added with stirring to 1.0 g of lithium aluminum hydride in 100 ml of dry tetrahydrofuran, over a period of 5 minutes. The light gelatinous precipitate that formed was stirred and refluxed for 8 hours after which time 7 ml of water was carefully added and the solvents were removed under reduced pressure.
The residue was acidified with dilute hydrochloric acid and brought to pH 8 with sodium hydroxide and sodium bicarbonate. The mixture was filtered and the filtrate and orange solid were separately extracted with chloroform. The combined, dried, chloroform solutions were evaporated to give 22 g of the crude basic triol as an orange solid, when triturated with ether. A portion of the material was recrystallized from ether/light petroleum (BP 40-60°C) to give a white solid, MP 109-111°C.
In an alternative process, sodium borohydride was used as the reducing agent, as follows:
36 g of 2-(benzyl-tert-butylamino)-4'-hydroxy-3'-hydroxymethyl acetophenone, hydrochloride was shaken with 100 ml of 10% sodium carbonate solution and 100 ml of ethyl acetate. The ethyl acetate layer was separated, washed with water, dried over anhydrous sodium sulfate and evaporated in vacuum.
The residual gum was dissolved in 360 ml of ethanol and cooled to 15°C in an ice/water bath, 8 g of sodium borohydride was then added in portions over 30 minutes while maintaining the temperature at 15-20°C. After a further 30 minutes at 20°C the solution was stirred at room temperature for 2 hours. The solution was again cooled in ice and 250 ml of 2 N sulfuric acid were slowly added, then the solution was evaporated in vacuum until the ethanol had been removed. The clear aqueous solution was then treated with 250 ml of 10% sodium carbonate solution and the oil which precipitated was extracted into ethyl acetate. The ethyl acetate layer was washed with sodium carbonate solution, then with water, and was dried over anhydrous sodium sulfate and evaporated in vacuum, to a small volume. Petroleum ether (BP 40-60°C) was added, and after standing overnight a white solid was obtained. This was filtered off to give 23 g of the product, MP 110-114°C.
(b) α1-tert-Butylaminomethyl-4-hydroxy-m-xylene-α1,α3-diol: 0.8 g of α1- benzyl-tert-butyl-aminomethyl-4-hydroxy-m-xylene-α1,α3-diol in 20 ml of ethanol and 2 ml of water was shaken with hydrogen in presence of 0.50 g of pre-reduced 10% palladium on charcoal catalyst. When uptake of hydrogen was complete, the solution was filtered and evaporated under reduced pressure to give 0,4 g of the base as a colorless oil which yielded a white solid, MP 144-145°C when triturated with ether/cyclohexane. Recrystallization from ethyl acetate-cyclohexane gave a white solid, MP 147-149°C.

Proventil (Schering); Ventolin (GlaxoSmithKline).

Bronchodilator

Levalbuterol is the R-(–)-isomer of albuterol and is available only in solution to be administered via nebulizer. Because it is the active isomer, the dose is fourfold less than that of albuterol. Pirbuterol is the pyridine isostere of albuterol. It has pharmacokinetics similar to albuterol but is half as potent at the β2-receptor. Pirbuterol is only available as an inhaler, whereas albuterol comes in tablet, syrup, solution, and aerosol formulations.

Synthesis, p. 966, 1988 DOI: 10.1055/s-1988-27768

β2-adrenoceptor agonist

Albuterol(18559-94-9) has the N-t-butyl and a salicyl alcohol phenyl ring, which gives it optimal β2-selectivity. It is resistant to COMT and slowly metabolized by MAO, giving it good oral bioavailability. Its onset by inhalation is within 5 minutes, with a duration of action between 4 and 8 hours. It currently is the drug of choice for relief of the acute bronchospasm of an asthmatic attack.

Adverse effects of pirbuterol are nervousness, tremor, and headache, which is less than the profile for albuterol, which adds nausea, vomiting, dizziness, hypertension, insomnia, tachycardia, and palpitations.

Albuterol, 2-tert-butylamino-1-(4-hydroxy-3-hydroxymethylphenyl)ethanol (11.1.26), basically differs from all of the aforementioned sympathomimetics in that the hydroxyl group at C3 of the aromatic ring is replaced with a hydroxymethyl group. It is synthesized in two ways. According to the first, it is prepared from 4-hydroxyacetophenone, the chloromethylation of which gives 4-hydroxy-3-hydroxymethylacetophenone (11.1.20). This is acetylated into a diacetyl derivative (11.1.21), which is further brominated into the corresponding bromoacetophenone (11.1.22). Reacting this with N-benzylN-tert-butylamine gives a derivative of aminoacetophenone (11.1.23), the acetyl group of which is hydrolyzed by hydrochloric acid, and the resulting product (11.1.24) undergoes a reduction?afirst by sodium borohydride for transforming the keto group into a hydroxyl group to give 11.1.25, and then by hydrogenation over a palladium catalyst for removing the benzyl-protecting group, giving albuterol (11.1.26) [26¨C30].

Tachycardia occurs as a reflex to the drop in mean arterial pressure (MAP) or as a result of b-1 stimulus. b-Adrenergic receptors in the locus coeruleus also regulate norepinephrineinduced inhibitory effects, resulting in agitation, restlessness, and hand tremor. Stimulation of nonpulmonary b2 receptors may lead to an increase in heart rate, QTc interval prolongation, nonspecific T-wave changes, skeletal muscle tremor, and slight increases in blood glucose and nonesterified fatty acids. Hypokalemia is more pronounced in patients receiving intravenous albuterol. Hypotension is also known to occur mostly in overdose. The buildup of cyclic AMP in the liver stimulates glycogenolysis and an increase in serum glucose.
In skeletal muscle, this process results in increased lactate production. Direct stimulus of sodium/potassium ATPase in skeletal muscle produces a shift of potassium from the extracellular space to the intracellular space. Relaxation of smooth muscle produces a dilation of the vasculature supplying skeletal muscle, which results in a drop in diastolic and MAP.Myocardial ischemia and infarction have been associated with excessive tachycardia in elderly patients. The skin may be warm and pink with evidence of diaphoresis.

Store at -20°C

Albuterol’s production and use as a bronchodilator may result in its release to the environment through various waste streams.