Planning reactions

To be able to define reaction planning, reaction prediction, and synthesis design To know how to acquire knowledge from reaction databases To understand reaction simulation systems... 

This is a question of reaction planning. To answer such a problem reagents and reaction conditions have to be found that allow one to perform the desired transformation. Such a question is best answered by a query into a reaction database (see Section 5.12). 

Pait/Piocess Numbei Pi ocess Name/Opeiation Descnption Macliine, Device, Jig, Tools, foi- Mfg Cliaiactei istics Special Cliai Class Methods Reaction Plan... 

This initial medicinal chemistry ELN was followed into the market by products such as the Arthur suite from Synthematix and the iELN system from Intellichem (both since acquired by Symyx), which were more oriented at reaction planning and process chemistry. The heavyweight of the traditional cheminformatics companies, Elsevier MDL, also released a system, called Elan, which combined a Word-based front end with their well-known ISIS chemical technology on the back end (Fig. 9.3). 

One of the fundamental and most important principles of Green Chemistry is that of atom economy. This essentially is a measure of how many atoms of reactants end up in the final product and how many end up in byproducts or waste. The percentage atom economy can be calculated as 100 times the relative molecular mass (RMM) of all atoms used to make wanted product divided by the RMM of all reactants. Box 1.2. The real benefit of atom economy is that it can be calculated at the reaction planning stage from a balanced reaction equation. Taking the following theoretical reaction ... 

Using the catalytic system described above, the enantioselective opening of meso epoxides could also be pursued. Although many excellent examples of ring-opening of meso epoxides by Sn2 reactions have recently been reported, the reaction planned here is conceptually different [40]. In the SN2 reaction, the path of the incoming nucleophile has to be controlled. In the titanocene-catalyzed reaction, the intermediate radical has to be formed selectively. If an intermediate similar to that invoked in the Bartmann ring-open-... 

The flow reactor is used primarily in the study of the kinetics of heterogeneous reactions. Planning of experiments and interpretation of data obtained in flow reactors are considered in later chapters. 

Process Step Output Input Spec Limit Process Capability Measurement System Current Control Method Who When/ Where Reaction Plan Transition Plan... 

Computer-assisted synthesis and reaction planning in combinatorial chemistry. Perspectives in Drug Discovery and Design, 20, 245-264. 

Gasteiger, J., et al., Computer-Assisted Synthesis and Reaction Planning in Combinatorial Chemistry, Persp. Drug Discov. Design, 20, 1, 2000. 

Reaction SMILES represents a specific reaction between specific reactants yielding specific products. As such, it can be very useful to store a library of reactions of interest. These might be a record of reactions that have been carried out at a company, a set of reaction plans in an academic research group, or even a set of hypothetical reactions that might never succeed in the laboratory. There is another extension of SMILES called SMIRKS that is more general and can represent a class of reactions. 

The rich chemistry of carbenium ions that may be accessed by the Friedel-Crafts acylation means that careful consideration must be given to any particular reaction planned, especially with regard to competing pathways. Nevertheless, the method remains an important, if relatively infrequently used, route to aliphatic ketones. 

Process Controls Engineers (continued) Equipment process capability Critical parameters process controls defined and reviewed Test equipment capability Review reaction plans for process failures... 

Where can I learn what I need to know about the reaction planned ... 

To begin work that demands familiarity with the chemical reactions planned, they need certain resources to answer the questions enumerated above. Information sources include their own stores of knowledge, their colleagues , and the appropriate chemical literature. 

The aldol reaction planned for target molecule 1 looks all right but enol formation has occurred on the wrong side. This is not surprising in add solution, so use base instead. 

Planning What subgrouping strategy wUl help us to leam the most about a process How often should measurements be made What is our reaction plan for out-of-control points ... 

REACTION PLAN FOR OUT OF CONTROL POINTS (attach copy)... 

A plan for reaction to special causes on the chart should be established. Often a checklist of items to evaluate or a flow chart of the steps to follow is useful. The reaction plan should state the transfer of responsibility for identification of the special cause if it cannot be done at the local level. A plan for reaction to special causes on the chart should be established. Often a checklist of items to evaluate or a flow chart of the steps to follow is useful. The reaction plan should state the transfer of responsibility for identification of the special cause if it cannot be done at the local level. As an example, a reaction plan for a control chart in a laboratory to monitor a measurement system might have the following reaction plan ... 

As in industry including butyl rubber chlorination and piperylene cationic oligomerization we often have to use liquid flows with different physical characteristics (density, viscosity) it is necessary to study the influence of these parameters on conditions of reaction plan front formation - quasi-plug-flow mode, and consequently on the effectiveness of external heat removal. 

The versatility of our reaction planning algorithms is demonstrated in our third example. The design of an isonitrile preparation method exemplifies the fact that reactions can be designed for specific purposes. 

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