High-speed parallel synthesis

Veeramaneni, V. R., Pal, M., and Yeleswarapu, K. R. 2003. A high speed parallel synthesis of 1,2-diaryl-l-ethanones via a clean-chemistry C-C bond formation reaction. Tetrahedron 59 3283-3290. 

Kappe CO, Kumar D, Varma RS (1999) Microwave-assisted high-speed parallel synthesis of 4-Aryl-3,4-dihydropyrimidin-2(lH)-ones using a solventless biginelli condensation protocol. Synthesis 10 1799-1803... 

In a dedicated combinatorial approach, Strohmeier and Kappe have reported the rapid parallel synthesis of polymer-bound enones [33]. This approach involved a two-step protocol utilizing initial high-speed acetoacetylation of Wang resin with a selection of common /i-ketoesters (Scheme 7.13) and subsequent microwave-mediated Knoevenagel condensations with a set of 13 different aldehydes (see Section 7.3.6). 

Parallel to these developments in combinatorial chemistry, microwave-enhanced organic synthesis has attracted a substantial amount of attention in recent years. As evidenced from the other chapters in this book and the large number of review articles available on this subject [7-14], high-speed microwave-assisted synthesis has... 

In another paper, a development of the microwave-assisted parallel solid-phase synthesis of a collection of 21 polymer-bound enones was described. The two-step protocol involves initial high-speed acetoacetylation of polystyrene resins with a selection of seven common P-ketoesters. When microwave irradiation at 170 °C was employed, complete conversions were achieved within 1-10 min, a significant improvement over the conventional thermal method, which takes several hours for completion. Significant rate enhancements were also observed for the subsequent microwave-heated Knoevenagel condensations. Reaction times were reduced to 30-60 min at 125 °C in the microwave protocol compared to 1-2 days using conventional thermal conditions. Kinetic comparative studies indicate that the observed rate enhancements can be attributed to the rapid direct heating of the... 

For high-throughput preparation of solid catalytic materials, automated robots equipped with synthesis control protocols are used. These robots carry out the various synthesis steps at high speed and in parallel or consecutively. The steps require high accuracy and reproducibiUty, without which no reliable data on optimal catalyst composition and best performance can be obtained. Moreover, the steps have to be performed in such a way, which is transferable to pilot- and technical-scale plant operation. For illustration, an automated sjmthesis robot is presented in Figure 2.3. 

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