HCID 13205461, Verbindung → 2H-Pyran-4-carboxylic acid, tetrahydro-, methyl ester
Reaktionsgleichung
[CH3:1][O:2][CH2:3][CH2:4][CH:5]1[CH2:9][CH2:8][O:7][C:6]1=[O:10].C(C1CCOC1=O)=C>CO>[O:2]1[CH2:3][CH2:4][CH:5]([C:6]([O:7][CH3:8])=[O:10])[CH2:9][CH2:1]1Komponenten
4
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Versuchsvorschrift
The patent examples demonstrate that when operating in the gas phase in the presence of fluidized Al2O3 catalysts at a temperature of from 240° to 270° C. yields of tetrahydropyrancarboxylate of only 36 to 42% are achieved (based on 3-(2'-hydroethyl)-dihydro-2(3H)furanone used)(Examples 1 and 2). The by-products formed under these conditions comprise from 18 to 20 % of 3-(2'-methoxyethyl)-dihydro-2(3H)furanone and from 16 to 27% of 3-vinyldihydro-2(3H)furanone. Example 1b demonstrates that the by-product 3-(2'-methoxyethyl)-dihydro-2(3H)furanone can be reacted with methanol to form methyl tetrahydropyran-4-carboxylate to give a yield of 26%. On the other hand, the reaction of the by-product 3-vinyldihydro-2(3H)furanone with methanol as described in Example 1c provides a yield of only 10%.