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Semi-synthetic antibiotic related to Penicillin. Antibacterial.

ChEBI: A hydrate that is the trihydrate form of amoxicillin; a semisynthetic antibiotic, used either alone or in combination with potassium clavulanate (under the trade name Augmentin) for treatment of a variety of bacterial infections.

Amoxicillin was synthesized by Beecham Research Laboratories in 1968. A hydroxyl group was introduced on the benzene ring of ampicillin. Amoxicillin shows about a twofold higher serum concentration than ampicillin when administered orally. It was shown by double-blind comparative studies with ampicillin that amoxicillin was as effective as ampicillin when administered at half the dose of ampicillin.

Arnoxil,Bencard,UK,1972

Ethyl chlorocarbonate (2.2 ml) was added to an ice cold solution of O,N-dibenzyloxycarbonyl-p-oxy-dl-α-aminophenylacetic acid (10 grams) and triethylamine (3.85 ml) in dry acetone (193 ml). The mixture was stirred at 0°C for 5 minutes during which triethylamine hydrochloride precipitated. The suspension was cooled to -30°C and stirred vigorously while adding as rapidly as possible an ice cold solution of 6-aminopenicillanic acid (5.85 grams) in 3% aqueous sodium bicarbonate (193 ml), the temperature of the mixture never being allowed to rise above 0°C. The resulting clear solution was stirred for 30 minutes at 0°C, and then for a further 30 minutes, without external cooling, and finally extracted with diethyl ether (3 x 200 ml) only the aqueous phase being retained.
This aqueous solution was brought to pH 2 by the addition of hydrochloric acid and the 6-(O,N-dibenzyloxycarbonyl-p-oxy-dl-α- aminophenylacetamido)penicillanic acid so liberated was extracted into diethyl ether (50 ml and 2 portions of 30 ml). The ether phase was washed with water (3 x 5 ml) and the water washings were discarded.
Finally, the penicillin was converted to the sodium salt by shaking the ether solution with sufficient 3% sodium bicarbonate to give a neutral aqueous phase, separating the latter and evaporating it at low pressure and temperature below 20°C. The product was finally dried over phosphorus pentoxide in vacuo to give sodium 6-(O,N-dibenzyloxycarbonyl-p-oxy-dl-α- aminophenylacetamido)-penicillanate (9.2 grams).
A suspension of palladium on calcium carbonate (36 grams of 5%) in water (150 ml) was shaken in an atmosphere of hydrogen at room temperature and atmospheric pressure for 1 hour. A neutral solution of sodium 6-(O,Ndibenzyloxycarbonyl- p-oxy-dl-α-aminophenylacetamido)penicillanate (9 grams) in water (100 ml) was then added and shaking in hydrogen was resumed for one hour. The suspension was then filtered and the collected catalyst was washed well with water without being allowed to suck dry between washings. The combined filtrate and washings were then brought to pH 6.5 with dilute hydrochloric acid and evaporated to dryness at reduced pressure and temperatures below 20°C. The product was finally dried over phosphorus pentoxide in vacuo to give a solid (5.4 grams) containing 6-(phydroxy- dl-α-aminophenylacetamido)penicillanic acid.

Amoxil (GlaxoSmithKline); Dispermox (Ranbaxy); Larotid (GlaxoSmithKline); Trimox (Apothecon) [Name previously used: Amoxycillin.].

Antibacterial