Study of the Chemistry of 3-Carbonyl-2-methylene-2,3- dihydrofuran and 3,4-Dicarbonyl-2,5-dimethylene- tetrahydrofuran

• Main Authors: Chen, Chun-An, 陳俊安
• Other Authors: Chou, Chin-Hsing
• Format: Others
• Language: zh-TW
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/57065183606087726116

碩士 === 國立中山大學 === 化學學系 === 82 === Part(1): Synthesis of 3-carbonyl-2-methylene-2,3- dihydrofuran(60) by the flash vacuum pyrolysis method has been studied.Pyrolysis of 3-carbonylfuran-2- acetic anhydride(59) gave furano[b-4,5]-2-(2-methyl- 3-furyl)-6-oxo-pyran-2-ene(68), buten-3-yne(66) and 2- methyl-3-furoic acid(69). Compound of 60 has been detected by low temperature NMR. Part(2):The temperature and pressure dependence of the products formed from pyrolysis of 2,5- dimethylfuryl-3,4-diacyl chloride(53) has been studied. Pyrolysis of 53 at 550oC and 1x10(-4)torr , using methanol as a trapping agent, gave dimethyl 2,5-dimethyl-3,4- dicarboxylate(73) and methyl 3- carbonyl-2,5-dihydrofuran-4- carboxylate(74). A result that supports the formation 3,4- carbonyl-2,5- dimethylenetetrahydrofuran(54). However , pyrolysis of 53 at 550oC and under the pressure of 1x10(-2)torr gave 2-methyl-3-thiophenooxy-5-thiophenoxyfuran(71) when thiophenol was used as a trapping agent, and 5- chlorohexa-5- en-2-one (60) and 4,5-dichloro-3,5-dien- 2-one(61) when no trapping agent was used. Such results suggest that, under lower vacuum condition, the primary pyrolysis product 54 will eliminate two molecules to form 2,5-dimethylene-3-furyne (59) as the secondary pyrolysis product. The reactive molecule 54 has been detected by low temperature NMR.