| Predicate |
Object |
| assignee |
http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_b0323ccb3e40d79a81b5774ebe5b164c
http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_066af93d226b9a8b1151cb1bc45bd190
http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_79316eeaf1bb028331ec423337beb09a |
| classificationCPCAdditional |
http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/Y02P20-55 |
| classificationCPCInventive |
http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C07D207-27 |
| classificationIPCInventive |
http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/C07D207-27 |
| filingDate |
2018-08-09-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| grantDate |
2022-11-15-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| inventor |
http://rdf.ncbi.nlm.nih.gov/pubchem/patentinventor/MD5_be5ecea6747849e3da8818b3f1d4b911
http://rdf.ncbi.nlm.nih.gov/pubchem/patentinventor/MD5_299818ef009e33869b5212b0594ba5d9
http://rdf.ncbi.nlm.nih.gov/pubchem/patentinventor/MD5_9a7acc8647c8fdb07566589f51bbd448
http://rdf.ncbi.nlm.nih.gov/pubchem/patentinventor/MD5_0c828f26df0c754c8623a447f1eb09cd |
| publicationDate |
2022-11-15-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber |
US-11498897-B2 |
| titleOfInvention |
Method for preparing levetiracetam |
| abstract |
A preparing method for high-purity levetiracetam, comprising: adjusting the pH of an extracted aqueous layer obtained by dissociating (S)-α-ethyl-2-oxo-1-pyrrolidineacetic acid (R)-methylbenzylamine salt to 5-9; removing water; adding an organic solvent to form a solution and then performing an esterification reaction with ethyl chloroformate or methylchlorofonmate; and carrying out an ammonolysis reaction to obtain the levetiracetam. The method simplifies production process, increases yield, reduces or even avoids the use of triethylamine in the esterification process, and reduces the emission of a great amount of three wastes. |
| priorityDate |
2017-08-10-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type |
http://data.epo.org/linked-data/def/patent/Publication |