Pharmaceutical API / Intermediate Synthesis

DMSO has been an essential part of numerous pharmaceutical syntheses that are currently in various clinical trial stages or commercial phases. Below are some specific pharmacological drug classes which benefit from the use of DMSO in manufacturing.



Azoles are substituted imidazoles that exhibit fungistatic activity at very low levels and are fungicidal at micromolar levels. Common fungicides used in agricultural and medicinal applications include itraconazole, ketoconazole, and miconazole.

As shown below, DMSO is primarily used to produce the ether linkage in this class of compounds.

Quinolone Antibiotics

The Quinolones have medicinal properties that make them important agents in the treatment of cystic fibrosis and bacterial infections. Important examples from this class include Ciprofloxacin hydrochloride and Norfloxacin.

The piperidine addition step is effectively performed in hot DMSO. DMSO is an especially useful solvent for nucleophilic substitution reactions using amine nucleophiles. Gaylord Chemical’s Comparative Reaction Solvent program has developed data which suggests that DMSO is the preferred solvent for such transformation even relative to other dipolar aprotic solvents.


DMSO is an important solvent in the synthesis of some macrolide antibiotics. In the clarythromycin process, it is the solvent used in the methylation step shown below.

In spite of the many hydroxyl groups available for alkylation, the hydroxyl moiety highlighted is selectively methylated in the process.

Some chemical reactions require the participation of DMSO as a reactive intermediate. Such DMSO Intrinsic Reactions are featured in a web-based seminar module accessible from the Learning Center.

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