Synthesizer Model 496 multiple organic

The model 496 Multiple Organic Synthesizer (Figure 13.7) has two robotic arms to deliver reagents and solvents to the Teflon reaction block. Standard monomer racks accommodate 10, 36, or 128 vessels (custom configurations are easy to adapt). The reagents in the racks are kept under an inert atmosphere. To pick up a reagent, the robotic arms pierce the septum at the top of the rack. In addition, six 100-mL reservoirs are available to store common reagents. 

The model 440 Multiple Organic Synthesizer is smaller than the model 496 (24 in. wide x 25 in. deep x 36 in. high). It is otherwise very similar to the model 496. The major difference is the reaction block, which has only 40 reaction vessels. However, the volume of each is 8 mL. 

In 1992, ACT replaced the Model 350 with the Model 396 Multiple Biomolecular Synthesizer. This instrument possesses two robotic arms, a variable speed orbital mixer, nitrogen assisted bottom filtration, a built-in ventilation system, protocols for both Fmoc and Boc synthesis and fully automated on-board cleavage for the Fmoc syntheses. It has reactor blocks of 8, 16, 40, and 96 wells for the synthesis of peptides from 5 pmol to 1 mmol. The Model 396 MBS also has a heater/cooler option for applications in solid-phase organic synthesis. 

The formation of crystalline microfibrils has been elucidated using the bacterium Acefol acter xylinum as cellulose producing model. It appears that individual cellulose chains are extruded at multiple cellulose-synthesizing sites located in the cytoplasmatic membrane of the organism. Cellulose synthesis produces 12 to 16 cellulose chains into the surrounding medium... 

A typical synthesis of complex organic molecules involves multiple reaction steps with intermediate purification of the intermediates. Such synthetic routes require a lot of labor-intensive manipulations and generate a lot of waste (e.g., solvents). With the atom-efficient biosynthetic pathways in cells as a model, several approaches have been developed in order to facilitate synthetic chemistry, such as protecting group-free syntheses [46], one-pot syntheses [47], cascade reactions [48], and multicomponent reactions [49]. More recently, synthetic chemists have been attracted by flow chemistry since it allows to combine all these processes in a single streamlined continuous process (i.e., multistep one-flow synthesis) [50]. Several strategies have been developed. 

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