1 - deoxynojirimycin synthetic route design and process optimization
|School||Nanjing Normal University|
|Course||Microbial and Biochemical Pharmacy|
|Keywords||1-deoxynojirimycin process optimization pilot scale|
In this paper, we designed a route of synthesis of 1-deoxynojirimycin (DNJ) with methyl a-D-glucopyranoside as the start materials. Based on this route, we optimized it and carried out small scale experiments under laboratory conditions to verify the feasibility of the optimal procedure to meet the standards of industrialized production. Then on the basis of the success of small scale experiments in the laboratory, we did pilot scale of this optimized route to explore the feasibility of industrial production. Results are as follows:1. We designed a route to synthesize 1-deoxynojirimycin after the literature review and reaction research. This route is taking methylα-D-glucopyranoside as the start materials, and the desired product has been gotten after five steps reactions. Each steps of the route were benzyl protected reaction, demethylation reaction, ring-opening reaction, the reaction of Pftizner-Moffat oxidation followed stereocontrolled intramolecular reductive aminaton, debenzylation reaction. Then we carried out small scale laboratory experiments with this route and got success finally. We used 77.6 gram reactant and got 6.79 gram desired product DNJ ultimately after five steps reactions. The general yield was 29.4% and the yields of each steps were:75%,65%,98.5%,72% and 85%.2. After verifying the feasibility of the reaction route through small scale experiments in laboratory, this study optimized this procedure to the capable of industrial production as standard. The optimization contents:Verify the by-product benzyl ether of step 1 reaction in the procedure don’t affect step 2 reaction, and so the processing steps after the reaction can be simplified; Optimize the solvent in step 2,4 and 5 reactions of original procedure; Change the catalyst LiAlH4 in original procedure to NaBH4; Change using lq. ammonia and lithium metal as reaction conditions in original procedure which is a bit difficult to be operated in industrial production to use Pd(OH)2 and H2 doing benzyl protection. Then we carried out small scale laboratory experiments with optimized procedure and got success finally. We used 195 gram reactant and got 7.4 gram desired product DNJ ultimately after five steps reactions. The general yield was 7.98% and the yields of each steps were:65%, 52%,90.2%,35% and 74.8%.3. We carried on two batches of pilot scale experiments to further verify the feasibility of industrial production with the optimized procedure. We used 20kg reactant in each batch of pilot scale experiments, got desired product 0.67kg and 1.63kg after reactions, the general yield were 8.03% and 7.95%, the average yield was 7.99% and it’s similar with the yield in small scale experiments. In the meantime, all the product we got from two batches of pilot scale experiments could reach 100% purity which verified the feasibility and stability of the optimized procedure. We can see from the results of the two batches pilot scale experiments that the experiments are designed reasonable and the reaction conditions are accurate in the optimized procedure, it’s qualified for industrial production.