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.
2,2,5-三甲基-5-苯基硒-1,3-二氧杂环戊烷-4,6-二酮在二氯甲烷中与间氯过苯甲酸发生氧化反应,生成含有以下成分的溶液
用间氯过苯甲酸在二氯甲烷中进行氧化,得到的溶液中含有
2,2-二甲基螺[1,3-二氧杂环戊烷-5,2'-环氧乙烷]-4,6-二酮和不稳定的
2,2-二甲基-5-亚甲基-1,3-二氧杂环戊烷-4,6-二酮的溶液。
环己二烯和环戊二烯形成稳定的加合物。环戊二烯加合物在
在 460-570° 的温度范围内对环戊二烯加合物进行闪烁真空热解,并检测热解产物中的成分。
通过质谱法检测热解产物中的成分,结果表明环戊二烯、丙酮、二氧化碳和甲烷都含有环戊二烯、
丙酮、二氧化碳和亚甲基乙烯(CH2=C=C=O);
最后一种在较高温度下(520-570°)分解成乙炔和一氧化碳。
(520-570°).在液氮温度下对热解产物进行的红外线测量显示,在 2100° 附近有吸收。
在液氮温度下对热解产物进行的红外测量显示,2100 cm-1 附近的吸收
2100 cm-1 附近的吸收归因于亚甲基乙烯。将热解产物与苯胺蒸气或甲醇蒸气反应
分别生成丙烯酰苯胺和丙烯酸甲酯。
在没有捕集剂的情况下进行热解,会在未冷却的玻璃表面上生成玻璃状固体。
玻璃表面形成玻璃状固体。这种固体被认为是在 2,2-二甲基-5-丙烯酸甲酯中加入亚甲基酮而形成的。
加到 2,2-二甲基-5-亚甲基-1,3-二恶烷-4,6-二酮中形成的。该固体的甲醇分解
与重氮甲烷进行酯化反应,得到 2-甲氧基羰基-4-亚甲基环戊二酸二甲酯。