Haloethylene-related compounds of industrial, environmental, and medical significance.
A broad-based literature survey was made for chemicals that contain either a haloethylene or a related substructure. Two hundred and sixty-two compounds, including synthetic intermediates, pesticides, solvents, drugs, food components, natural products, and metabolites, are grouped by their structures. Some are in current use or are bioavailable while little exposure is expected from others. As more biologic-response information is reported for small compounds of these types, it should become possible to select others for research on additional questions of structure-activity relationships. Some of the compounds are widespread while others are not. Some are used or found in large amounts while others may be trace contaminants, minor or more major by-products of synthesis or isolation. The pesticides and solvents, for example, are knowingly and often deliberately released to the environment, sometimes in very large quantities. Inadvertent release also occurs, sometimes referred to as fugitive emission. Food contaminants and drugs are directly accessible to humans. Sparsely distributed natural products could be accessible to humans, for example, via the food chain. Some of the compounds in food may be formed during preparation, storage or metabolically. Last, the haloethylene function has often been synthesized into compounds in order to achieve desired biologic activities. There are many types and degrees of relatedness of structure, depending upon atomic dimensions and stereochemical, polar, resonance, and other factors. Furthermore, for some chemical series, biologic responses are continuously variable while, in other cases, it is not uncommon that qualitatively different types of response occur with apparently very close homologs. Genetic, metabolic, and behavioral factors affecting response must also be considered. Thus, safety or hazard cannot yet be predicted conclusively by apparent relatedness of structure alone. Also, since the tables are noncomprehensive, some relevant compounds have likely been omitted. The haloalkanes, for example, are not here because of their large number, despite the knowledge that some are either metabolized or nonbiologically converted to haloalkenes.