http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-813756-A
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_232361c9031a709144573276863c462b |
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C07J5-00 http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C07J75-00 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/C07J75-00 http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/C07J5-00 |
| filingDate | 1956-07-30-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| inventor | http://rdf.ncbi.nlm.nih.gov/pubchem/patentinventor/MD5_184be722146a7975993c772f16ee373a http://rdf.ncbi.nlm.nih.gov/pubchem/patentinventor/MD5_fe20f6e104347c172e4b019c254821fe |
| publicationDate | 1959-05-21-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-813756-A |
| titleOfInvention | Improvements in or relating to the preparation of new steroid substances |
| abstract | The invention comprises 2,4-dibromo-3-keto-11b -hydroxyallosteroids and a process for their preparation by brominating the corresponding 3-keto-11b -hydroxyallosteroids in a medium containing a solvent which is inert to the steroid but which is reactive with hydrogen bromide present substantially to inhibit side-reactions without substantial inhibition of the desired reaction, e.g. open chain and cyclic ethers, particularly diethyl ether, isopropyl ether, dioxane and tetrahydrofuran. The medium may contain other diluents, e.g. saturated chlorinated hydrocarbons such as chloroform, methylene dichloride and ethylene dichloride, and acetic acid. The process is normally effected between -10 DEG and +40 DEG C., preferably between +5 DEG and +20 DEG C., using from 2.0 to 2.5 molecular equivalents bromine/mol. steroid. In examples: (1) 11b -hydroxyergostan-3-one in dioxane containing a trace of HBr is brominated to 2a ,4a - dibromo - 11b - hydroxy - ergostan - 3-one; (2) to (6) 4,5a -dihydrocortisol 21-acetate is brominated to 2,4-dibromo-4,5a -dihydrocortisol 21-acetate in dioxan (with and without HBr), methylene chloride - isopropyl ether, methylene chloride - tetrahydrofuran, and methylene chloride - diethyl ether respectively; (7) 21 - acetoxy - 11b ,17a - dihydroxy - 5a - pregnane - 3,20 - dione is brominated in dioxane containing a trace of HBr, the resulting dibromo steroid refluxed in acetone with sodium iodide and bromoacetone, treated with chromous chloride solution, the product treated with Girard P reagent and then 40 per cent aqueous formaldehyde, finally giving cortisol 21-acetate; (8) 4,5a -dihydrocortisol 21-acetate is brominated in tetrahydrofuran-acetic acid containing HBr and the resulting 2,4-dibromo compound (contaminated with 4-bromobutyl acetate) dehydrobrominated to prednisolone acetate. The Provisional Specification further mentions t-butanol and acetonitrile as suitable solvents for the bromination process. Specification 811,632 is referred to. |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
Total number of triples: 68.