http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-739128-A
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_653f5c196338bcb4c8f94debd09cdaad |
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C07D309-30 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/C07D309-30 |
| filingDate | 1954-09-09-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationDate | 1955-10-26-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-739128-A |
| titleOfInvention | 2-alkoxy-3:4-dihydro-1:2-pyran derivatives, and process for their preparation |
| abstract | The invention comprises 2-alkoxy-3 : 4-dihydro-1 : 2-pyrans of the general formula <FORM:0739128/IV (b)/1> and their preparation by heating an unsaturated ether of formula RO.CH : CR1R2 with an unsaturated aldehyde R3CH : CR4.CHO under pressure, preferably in an autoclave between 150 DEG and 300 DEG C. In the above formul R and R1 are alkyl groups each having from 1 to 12 carbon atoms, R2 is hydrogen or an alkyl group having not more than 12 carbon atoms, and R3 and R4 are hydrogen or alkyl groups having up to 5 carbon atoms. Specified unsaturated ethers are 1-propen-1-ol, 1-buten-1-ol, 2 - methyl - 1 - propen - 1 - ol, 2 - ethyl - 1-buten - 1 - ol, 1 - hexen - 1 - ol, and 2 - ethyl-1-hexen-1-ol; and unsaturated aldehydes mentioned include acrolein, methacrolein, crotonaldehyde, 2-ethyl-2-hexenal, 2-propyl-2-hexenal, 2-ethyl-2-butenal, 2-methyl-2-pentenal, 2-hexenal, 4-ethyl-2-hexenal and 2-butyl-2-octenal. A polymerization inhibitor, e.g. pyrogallol, t-butyl catechol, and hydroquinone may be added to the reaction mixture, particularly when acrolein or methacrolein is a reactant. In examples: (1) acrolein, 1-butenyl methyl ether and hydroquinone are autoclaved and the product fractionated to yield 2-methoxy - 3 - ethyl - 3 : 4 - dihydro - 1 : 2-pyran; (2) 2-ethyl-2-hexenal, 1-propenyl methyl ether and hydroquinone similarly yield 2 - methoxy - 3 - methyl - 4 - propyl - 5 - ethyl-3 : 4 - dihydro - 1 : 2 - pyran; (3) as in (1) but using 1-propenyl methyl ether, to give 2-methoxy - 3 - methyl - 3 : 4 - dihydro - 1 : 2-pyran; (4) as in (1), using crotonaldehyde to give 2 - methoxy - 3 - ethyl - 4 - methyl - 3 : 4-dihydro-1 : 2-pyran. Reference is also made to the formation of 2-methoxy-3 : 4-dimethyl-5 - ethyl - 3 : 4 - dihydro - 1 : 2 - pyran from 2 - ethyl - 2 - butenal and 1 - propenyl methyl ether, and 2-methoxy-3 : 3 : 4-trimethyl-3 : 4-dihydro - 1 : 2 - pyran from crotonaldehyde and 2-methyl-1-propenyl methyl ether. Hydrolysis of the methoxytrimethyldihydropyran yields 2 : 2 : 3-trimethylglutaraldehyde. 2-Methyl-1-propenyl methyl ether is prepared by decomposition of the dimethyl acetal of isobutyraldehyde. |
| isCitedBy | http://rdf.ncbi.nlm.nih.gov/pubchem/patent/US-2972621-A |
| priorityDate | 1952-10-02-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
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