ABSTRACT
Primary agrochemical producers a decade ago typically screened 104 to 5 X 104 compounds per company per year. Most of the compounds were a diverse random group of chemicals from other divisions within the company, or obtained from outside collaborators. Some compounds were specifically synthesized in-house for optimization of perceived lead chemi cals. Now, companies plan on screening ten times more compounds per year (which is not that many more compounds industry wide, as there are far fewer companies than a decade ago), mainly by combinatorial tech niques. Combinatorial chemistry is a technique to generate large numbers of related compounds in a short time from a single precursor component bound to a solid support and multiply derivatized during removal from the support by eluting with different reactants. Time will tell whether this mode of increasing numbers while decreasing diversity yields more lead structures than before. Combinatorial synthesis is an excellent way to synthesize large number analogs of newly found leads for structure-activity relationships with minimum intellectual input. Again, whether that proves superior to the intuitive design of fewer analogs by highly experienced chemists, as was previously done, remains an open question.
