Synthesis tree

Condenser. To produce a saturated liquid at 6°C, the phase-change operation is carried out by a condenser that transfers heat to a mild refrigerant. Then the pressure is lowered to 12 atm across a valve. 

Recycle cooler. To prevent vapor from entering the pump, when the recycle stream is mixed with effluent from the dichlorination reactor, the recycle stream is cooled to 90°C (below the boiling point of dichloroethane at 1.5 atm) using cooling water. 

Similar screening techniques are applied by the design team in every step, as discussed throughout this book. 

To satisfy the objective of generating the most promising flowsheets, care must be taken to include sufficient analysis in each synthesis step to check that each step does not lead to a less profitable flowsheet or exclude the most profitable flowsheet prematurely. For this reason, it is common practice in industry to mix these synthesis steps with analysis using the simulators introduced in the next chapter. 

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After a strategic bond has been broken and precursor molecules have been obtained, a new level is added to the synthesis tree. Between two levels of the tree the synthesis tree branches out into precursors In addition, a new... 

A drawback of this approach is that it typically generates enormous and imwieldy synthesis trees which contain a large number of dead-end branches which are not worth further consideration. Furthermore, the chemist is forced to follow a rigid scheme during the planning process, alternating between the application of transforms, the derivation of new precursors, and again the application of further transforms to these precursors. 

Figure 10.3-56. Entire synthesis tree for target compound 1.

The design of the synthesis foi 1 is now finished. The target eompound (1) can be simplified to eommeicially available starting materials which can easily be converted to the target compound in the synthesis direction, Figure 10.3-56 shows the entire synthesis tree interactively developed with the WODCA program. 

Diethylphosphoryl cyanide 3 as a reagent lor amide bond lormation and applicallon to peptide synthesis tree ol racemization. 

As an illustrated example of these ideas presented thus far we show in Scheme 4.8 and Figure 4.14 the conventional synthesis plan for triclosan and its corresponding synthesis tree diagram. 

Figure 4.14 Synthesis tree for triclosan synthesis plan shown in Scheme 4.8. Molecular weights for each species are shown within parentheses.

Figure 4.15 shows the same synthesis tree for triclosan as given before in Figure 4.14 with some modifications made and added geometric parameters superimposed. The... 

Figure 4.16 Summary of parameters for all combinations of synthesis trees involving four input reagents.

Figure 4.19 Synthesis tree for nicotine plan 1 (Craig, 1 933).

Figure 4.20 Synthesis tree for nicotine plan 2 (Spath, 1 928).

Figure 4.21 Synthesis tree for nicotine plan 3 (Lebreton, 2001).

Figure 4.22 Synthesis tree for nicotine plan 4 (Chavdarian, 1982).

Figure 4.23 Synthesis tree for nicotine plan 5 (Helmchen, 2005).

Figure 4.26 Synthesis tree for nicotine plan 8 (Jacob, 1 982).

Figure 4.28 Synthesis tree for nicotine plan 10 (Campos, 2006).

Figure 4.29 Synthesis tree for nicotine plan 11 (Pictet, 1 895-1 904).

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