Decarboxylation and Elimination

Drug substances having a carboxylic acid group are sometimes susceptible to decarboxylation, as shown in Scheme 42. 4-Aminosalicylic acid is a good example.168 Foscarnet also undergoes decarboxylation under strongly acidic conditions, 169 whereas etodolac is susceptible to decarboxylation by acid catalysis.170

Other elimination reactions have been reported for various drug substances, as shown in Scheme 43. Trimelamol eliminates its hydroxymethyl groups and forms formaldehyde.171 Levothyroxine eliminates iodine. 172 ADD-17014, a derivative of triazoline, eliminates nitrogen and forms a derivative of aziridine.173 Ditiocarb eliminates carbon disulfide.174

Scheme 38. Racemization of epinephrine.

Scheme 38. Racemization of epinephrine.

Scheme 39. Racemization of oxazepam.
Moxalactam
Scheme 40. Epimerization of moxalactam.
Street Drugs Elimination Times

COOH

Scheme 41. Epimerization and hydrolysis of hetacillin.

Decarboxylation Catalyst

Scheme 42. Representative drug substances that are susceptible to decarboxylation.

etodolac

Scheme 42. Representative drug substances that are susceptible to decarboxylation.

Scheme 43. Other drug substances that are susceptible to elimination reactions.

ditiooarb

Scheme 43. Other drug substances that are susceptible to elimination reactions.

Continue reading here: Oxidation

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