The Reaction of Bases with Chloroform

Solvent Derived Artifacts in Natural Products Chemistry

Solvents play an important and critical role in natural product chemistry. They are mainly used during the extraction and purification of metabolites from a biological matrix. To a lesser extent, solvents are also used as reagents or catalysts to perform chemical reactions. This review focuses on the most important classes of solvents, including alcohols, halogen-containing solvents, esters, ethers, acids and bases. The chemical reactions associated with the use of these solvents to form the so-called “artifacts” are discussed and the most common contaminants found in these solvents are also reviewed. The formation of artifacts and the use of contaminated solvents mainly leads to the formation of new compounds, loss of activity of active compounds, formation of active compounds from inactive ones (false positives), loss in total yield of important compounds during isolation, formation of toxic compounds and difficulty in reproducing an extraction or purification method. Finally, the need for stability studies of purified natural products is emphasized, as this is a common overlooked aspect in natural product chemistry.

Artifacts produced by using dichloromethane in the extraction and storage of some antihistaminic drugs

The use of dichloromethane for the extraction of amines may lead to the formation of artifacts. Dichloromethane reacts rapidly (37.5 degrees) with brompheniramine, diphenylpyraline, cyclizine, cyproheptadine but not with antazoline and lignocaine. This difference in reactivity as well as the thin-layer chromatographic, gas-liquid chromatographic, nuclear magnetic resonance, and mass spectrometric characteristics of cyclizine and diphenylpyraline chloromethochlorides are investigated.