中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
—— | hexamethyl pentane-1,1,3,3,5,5-hexacarboxylate | 123298-11-3 | C17H24O12 | 420.37 |
三甲基丁-3-烯-1,1,3-三羧酸酯 | 2-(methoxycarbonyl)-4-methylenepentanedioic acid dimethyl ester | 61245-10-1 | C10H14O6 | 230.218 |
环丙烷-1,1,2,2-四羧酸四甲酯 | cyclopropane-1,1,2,2-tetracarboxylic acid tetramethyl ester | 7605-66-5 | C11H14O8 | 274.227 |
Oxidation of 2,2,5-trimethyl-5-phenylseleno-1,3-dioxan-4,6-dione with m-chloroperbenzoic acid in methylene chloride gives a solution containing 2,2-dimethylspiro[1,3-dioxan-5,2'-oxiran]-4,6-dione and the unstable 2,2-dimethyl-5-methylene-1,3-dioxan-4,6-dione, which forms stable adducts with cyclohexadiene and cyclopentadiene. Flash vacuum pyrolysis of the cyclopentadiene adduct over the temperature range 460- 570° and detection of the components present in the pyrolysate by mass spectrometry showed that cyclopentadiene, acetone, carbon dioxide and methyleneketene (CH2=C=C=O) are formed; the last breaks down into acetylene and carbon monoxide at higher temperatures (520-570°). Infrared measurements on the pyrolysis products kept at liquid nitrogen temperature showed absorption near 2100 cm-1 which is attributed to methyleneketene. Reaction of the pyrolysate with aniline vapour or methanol vapour yielded acrylanilide and methyl acrylate respectively. Pyrolysis in the absence of trapping agents gave a glassy solid on an uncooled glass surface. This solid is considered to be formed by addition of methyleneketene to 2,2-dimethyl-5-methylene-1,3-dioxan-4,6- dione. Methanolysis of the solid and esterification with diazomethane gave dimethyl 2-methoxycarbonyl-4-methylenepentanedioate.