Isotopically Modified Compounds
This chapter describes a general system of nomenclature for isotopically modified organic compounds, i.e., compounds in which the isotopic ratio of nuclides for at least one element deviates measurably from that occurring in nature. Isotopically modified compounds are divided into, isotopically substituted compounds and isotopically labeled compounds. An isotopically substituted compounds has a compositions such that essentially all the molecules of the compound have only the indicated nuclide at each designated position. Although an isotopically labeled compound is really a mixture as far as chemical identity is concerned (in the same way as is an unmodified compound), for nomenclature purposes, such mixtures are called isotopically labeled compounds. Four kinds of isotopically labeled compounds are described, specifically labeled, selectively labeled, nonselectively labeled, and isotopically deficient. Isotopically labeled compounds can be generally or uniformly labeled.