A peptide synthesis system

The system incorporates a vertically positioned single reaction vessel manufactured from an inert fluorocarbon polymer that generally operates at the 0.1 or 0.2, mmol scale with 10 ml and 40 ml reaction vessels, respectively. 

A range of reaction vessels are available to enable synthesis scales ranging from 0.005 to 1.0 mmol (3 ml reaction vessel for 0.005,0.010, and 0.025 mmol 10 ml reaction vessel for 0.1 mmol 40 ml reaction vessel for 0.25 mmol 55 ml reaction vessel for 1.0 mmol). Different sizes of reaction vessels are required to enable resin swelling and efficiency of washing steps. Mixing in the reaction vessel occurs by vortex agitation that allows for efficient resin-fluid interaction. 

Two different types of activation are generally used on the Model 433A, namely HBTU or HOBt-DCC. Activation with HBTU is also referred to as FastMoc chemistry. In the activation step of the 0.25 mmol and 0.10 mmol FastMoc cycles, 1.0 mmol of dry protected amino acid in the cartridge is dissolved in solutions of HBTU-HOBt and JV,A-diisopropylethylamine (DIPEA) in DMF with additional NMP added. The FastMoc 1.0 mmol cycles use three 1.0 mmol cartridges, or a total of 3.0 mmol of Fmoc amino acid. The activated Fmoc amino acid is formed rapidly and the solution transferred directly to the reaction vessel. All washing steps are performed with NMP and Fmoc deprotection is achieved by treatment with piperidine-DMF (1 4). Cycle times are 24, 45, and 70 min for the 0.1, 0.25, and 1.0 mmol scales, respectively, with times potentially increasing when feedback monitoring is 

The system incorporates nine solvent/reagent reservoirs to enable delivery of the NMP main wash, neat piperidine deblock (diluted with main wash on line), 0.45 M HBTU-HOBt-DMF activator solution, 2.0 M DIPEA-NMP, MeOH final wash, DCM wash, alternative activators (e.g. 1.0 M DCC-NMP), capping solution, and solvent exchange for Fmoc/rBu chemistry. In the case of Boc/Bzl-based methods, DCM and NMP are used as the main wash solvents, TFA (diluted with DCM on-line) for deblock, 1.0 M DCC-NMP and 1.0 M HOBt-NMP for activation, DMSO-NMP (4 1) for improved solvation, acetic anhydride for capping, and MeOH for final wash. A gas positive-pressure chemical delivery system controls the flow of all reagents and solvents. Gas pressure is provided by an external tank of nitrogen. 

In the Model 433A SynthAssist Software, based on a Macintosh platform, there are 152 functions, designated with a number and a name, which control all the processes required for synthesis. Some functions activate a switch or set of switches to deliver solutions or to perform a specific task. 

---