The first mass producers of chemicals became active in the 1800s, and over the last two centuries scientific and technological advances have made a tremendous number of chemical substances available. Some of these many chemical products are meant to be directly utilized in the form in which they are sold, as is the case with pharmaceuticals. However, a great number of the substances produced by the chemical industry, including chloroisatin, are intermediates, which are intended to be used as a middle stage in the manufacture of some other desired end product. Indeed, the majority of synthetic processes are based upon the transformation of one or more readily available and often inexpensive intermediates, and, therefore, a vast array of these substances are commercially available through chemical supply companies.