http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-683344-A
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_c7ad58d3c0b071069a8ee0cb8c8ba2e8 |
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C07D311-16 http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C07D311-18 http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C07D311-92 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/C07D311-92 http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/C07D311-18 http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/C07D311-16 |
| filingDate | 1950-11-24-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationDate | 1952-11-26-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-683344-A |
| titleOfInvention | Process of making substituted 4-methyl coumarins |
| abstract | 4-Methylcoumarins, containing a substituent in the benzene nucleus or having a further ring fused thereto, are manufactured by the action of a dehydrating condensing agent on an acetoacetic ester of the general formula <FORM:0683344/IV (b)/1> (wherein R represents one or more substituents or a fused-on ring) obtainable by reacting the corresponding phenol with an equimolecular proportion of diketene in the presence of an esterification catalyst at an elevated temperature not substantially above the melting point of the phenol. Suitable starting materials (which need not be isolated in the pure state) are the acetoacetates of the phenol homologues (e.g. cresols and xylenols) and the naphthols, and the mono-acetoacetates of polyhydric phenols. The condensation is advantageously effected by running the acetoacetate into the condensing agent at a temperature between 0 DEG and about 50 DEG C. In examples: (1) resorcinol is fused with a small amount of pyridine and an equimolecular proportion of diketene is run in, and the resulting monoacetoacetate is run into 78 per cent sulphuric acid, producing methyl umbelliferone; (2) pyrogallol similarly yields 7 : 8-dihydroxy-4-methylcoumarin; (3) 6-hydroxy-4-methylcoumarin is similarly prepared from hydroquinone, except that the first step is carried out in benzene solution; (4) a -naphthol is treated as in (1) to produce 4-methyl-1 : 2-a -naphthopyrone; (5) diketene is run in a slow jet into a heated mixture of p-cresol with a trace of dimethylaniline, and the resulting acetoacetate is treated as in (2) to form 4 : 6-dimethylcoumarin; (6) resorcinol is reacted with diketene in the presence of triethylamine and the product is run into concentrated phosphoric acid, producing methylumbelliferone. Zinc chloride is additionally specified as a condensing agent, and sodium acetate, benzenesulphonic acid and concentrated sulphuric acid as esterification catalysts. |
| isCitedBy | http://rdf.ncbi.nlm.nih.gov/pubchem/patent/US-5231194-A |
| priorityDate | 1949-11-25-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
Total number of triples: 59.