Automated synthesis and combinatorial chemistry

Development and Commercialization of the MiniBlock Synthesizer Family: A Historical Case Study

An internal development project at Bristol-Myers Squibb (BMS) led to invention of a family of organic chemistry synthesis blocks for both parallel synthesis in drug discovery and parallel reaction optimization in pharmaceutical development. The internal demand for these synthesis blocks became so great that the original development team was challenged by the burden of ongoing manufacture, support, and supply chain management. As a result, BMS entered into a unique industry partnership with Mettler-Toledo AutoChem (MT), Newark, DE, formerly Bohdan Automation, to commercialize the reactor blocks and extend the product family, now known as the MiniBlock line. This manuscript describes the initial development drivers, the overall technical design, and the ultimate successful commercialization of the MiniBlock synthesis family.

Combinatorial chemistry as a tool for drug discovery

The question 'will combinatorial chemistry deliver real medicines' has been posed [96]. First it is important to realise that the chemical part of the drug discovery process cannot stand alone; the integration of synthesis and biological assays is fundamental to the combinatorial approach. The results presented in Tables 3.1 to 3.8 suggest that so far smaller directed combinatorial libraries have obtained equivalent results to those obtained previously from traditional medicinal chemistry analogue programs. Unfortunately, because of the long time it takes to develop pharmaceutical drugs there are no examples yet of marketed drugs discovered by combinatorial methods. There are interesting examples where active leads have been discovered from the screening of the same library against multiple targets (e.g. libraries 13, 39, 43, 66, 71 and 76). It is now possible to handle much larger libraries of non-oligomeric structures and the chemistry required for such applications is becoming available. Whether combinatorial approaches can also be adapted to deal with all the other requirements of a successful pharmaceutical (lack of toxicity, bioavailability etc.) is open to question but there are already examples such as cassette dosing [235-237]. However we can still be optimistic about the possibility of larger libraries producing avenues of investigation for the medicinal chemist to develop into real drugs. Combinatorial chemistry is an important tool for the medicinal chemist.

Automated synthesis: new tools for the organic chemist

Routine automation of organic chemistry had proved an elusive goal until the arrival of combinatorial chemistry and the economic pressures of increased drug discovery throughput. Now, several approaches have been used to automate chemical synthesis, resulting in a range of new tools, both large and small, to support the process of compound production. The availability of these tools to the organic chemist heralds the change from the traditional 'hand-crafted' philosophy to a more mechanized view of compound synthesis in drug discovery groups.

Combinatorial chemistry, automation and molecular diversity: new trends in the pharmaceutical industry

Combinatorial chemistry has emerged as a set of novel strategies for the synthesis of large sets of compounds (combinatorial libraries) for biological evaluation. Within a few years combinatorial chemistry has undergone a series of changes in trends, which are closely related to two important factors in libraries: numbers and quality. While the number of compounds in a library may be easily expressed, it is a lot more difficult to indicate the degree of quality of a library. This degree of quality can be split into two aspects: purity and diversity. The changing trends in combinatorial chemistry with respect to the strategies, the technologies, the libraries themselves (numbers and purity aspects) and the molecular diversity are outlined in this paper.

The impact of polystyrene resins in solid-phase organic synthesis

A major objective of the DIVERSOMER technology is to provide pure and characterized compounds for biological testing in order to prevent 'false negatives' in our libraries. On several occasions, analysis of the final products by 1H-NMR and MS, has revealed by-products from the polystyrene solid support. Subsequently, three alternative methods were studied to remove polystyrene by-products; (i) prewashing of the resin prior to execution of the synthesis; (ii) pretreatment of the resin with the cleavage conditions consistent with the solid-phase synthesis reaction scheme; and (iii) parallel purification.