http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-582872-A
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_b4982f67e44e5b9dbfc41ee6302d9468 http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_51504e7bffdc9e15086507fa932286a2 |
| filingDate | 1944-09-21-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationDate | 1946-11-29-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-582872-A |
| titleOfInvention | Improvements in or relating to the production of naphthyridones and of naphthyridines therefrom |
| abstract | Naphthyridones are obtained by treating a 2-azafluorenone or substitution product thereof with hydrazoic acid or a source thereof, in presence of a mineral acid, advantageously sulphuric acid, the quantity of hydrazoic acid used being somewhat in excess of 1 molecular proportion. The benz-naphthyridones so obtained are converted into the corresponding halogen-benznaphthyridines which are then employed for the production of other substituted benznaphthrydines. The halogen derivatives may be obtained by known methods for converting hydroxypyridine, -quinoline or -phenathridine derivatives into the corresponding halogen compounds, a preferred method consisting in heating the benznaphthridone with a phorphorus oxyhalide or with a phosphorus pentahalide in phosphorus oxyhalide suspension at elevated temperature, preferably between 170 and 190 DEG C. Reaction is effected in a sealed vessel or alternatively the reactants are heated in an open vessel in an inert high-boiling solvent medium, e.g. nitrobenzene or a dialkylamine such as diethylaniline. In examples: (1) 1 : 3-dimethyl-2-azafluorenone in concentrated sulphuric acid is treated with aqueous sodium azide and the product is poured into ice to precipitate the corresponding sulphate, from which is isolated 6 : 8-dimethyl-3 : 4-benzo-1 : 7-naphthyrid-2-one by treatment with dilute ammonia; (2) the product of (1) and phosphorus oxychloride are heated in a sealed tube at 180 DEG C., the residual oil being treated with ice and excess ammonia to isolate 2-chloro-6 : 8-dimethyl-3 : 4-benzo-1 : 7-naphthyridine; (3) the product of (1) and phosphorus oxychloride are heated in a sealed tube at 180 DEG C. and the residue, after cooling, is treated as in (3), (4) 4-carbethoxy-1 : 3-dimethyl-2-azafluorenone in concentrated sulphuric acid is treated with aqueous sodium azide as in (1) and the product was treated with ice-ammonia, the pptd. sulphate being dissolved in 5 per cent sodium hydroxide, and the filtrate saturated with carbon dioxide to isolate 4-carbethoxy-6 : 8-dimethyl-3 : 4-benzo-1 : 7-naphthyrid-2-one, the enolic form being 4-carbethoxy-6 : 8-dimethyl-3 : 4-benzo-2-hydroxy-1 : 7-naphthyridine. 1-Carbethoxy-4 : 3-dimethyl-2-azafluorenone is obtained by treating the corresponding 4-carboxy compound in ethanolic N/2 potassium hydroxide with aqueous silver nitrate, heating under reflux with ethyl iodide an alcoholic suspension of the silver salt so precipitated, and diluting the concentrated filtrate with water. |
| priorityDate | 1944-09-21-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
Total number of triples: 47.