- Synthetic method of dimethyl acetyl succinate
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The invention relates to a synthetic method of dimethyl acetyl succinate. The synthetic method comprises the following steps: esterification reaction; acetylation reaction: adding dimethyl maleate andmethanol into a reactor, starting stirring, dropwise adding acetic anhydride into the reactor, adding sodium borohydride solid powder at the same time, and performing a constant-temperature reactionto obtain an acetyl compound solution; extracting: adjusting the pH value of the acetyl compound solution by using a sodium carbonate solution; adding the solution into a rotary evaporator, evaporating excessive methanol and part of water in the solution, putting the rest part into a separating funnel, standing for layering, separating out a water phase, washing an organic phase with purified water, evaporating residual water in the organic phase in vacuum, and slowly cooling to the normal temperature to obtain a dimethyl acetyl succinate solid. Acetic anhydride is used as an acylating agent for acetylation reactions, the optimal reaction conditions are selected, the reaction yield is increased to 96.71%, the reaction process is carried out under a normal pressure, and the influence of thepurity of dimethyl maleate on the yield of DMAS is reduced.
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Paragraph 0031-0051
(2020/08/09)
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- Alkoxycarbonylcarbene Transfer to Acyclic Tertiary Enaminones
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Copper-catalyzed alkoxycarbonylcarbene transfer from methyl or tert-butyl diazoacetate to acyclic enaminoesters 6a,b and enaminocarboxanilide 13 yields vicinal push-pull-substituted cyclopropanes 7a,b, 8, and 14. In contact with dry silica gel, the latter compounds undergo facile ring-opening leading to enaminoesters 9,10, and 15. Treatment with aqueous acid transforms 9 and 10 into 2-acylsuccinates 11 and 12, and 15 into pyrrolinone 16. Methoxycarbonylcarbene transfer to enaminoketones 1a-c does not yield isolable cyclopropanes, but after hydrolytic work-up α-acyl-γ-ketoesters 2a-c are obtained.
- Maas,Mueller
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p. 315 - 322
(2007/10/03)
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- THE PHOTOCHEMISTRY OF METHYL GERANATE, A MODEL CHROMOPHORE FOR INSECT JUVENILE HORMONE ANALOGS
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The irradiation of methyl geranate (3) in ether using 254 nm lamps produces methyl 5-methyl-2-isopropenyl-4-hexenoate (13), 1,6,6-trimethyl-endo-5-carbomethoxybicyclo-hexane (11), methyl 2-isopropenyl-5-methylcyclopentanecarboxylate (12) and methyl (3Z)-3,7-dimethyl-3,6-octadienoate (14).Photolysis run in water or in ether in the presence of base generates two additional dienes: methyl 3-methylene-7-methyl-6-octaenoate (16) and methyl (3E)-3,7-dimethyl-3,6-octadienoate (17).The photolysis of methyl (2E, 6E)-3,7-dimethyl-2,6-nonadienoate (4a) in ether procedures all Z/E isomers, 4a - 4d.
- Freeman, Peter K.,Siggel, Lorenz,Chamberlain, Paul H.,Clapp, Gary E.
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p. 5051 - 5064
(2007/10/02)
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- 4-(Phenylthio)-pyrrole-3-carboxylic Acid Esters
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Dihydro(dimethoxy)methylfurancarboxylic acid esters 4A/4B have been applied to the synthesis of the title compounds.With amines as catalysts they react with thiophenols to give the addition products 12a-d, which upon heating with acids eliminate methanol to form the furancarboxylic acid esters 13a-b and 17, whereas reactions with ammonia or amines lead to the pyrrolecarboxylic acid esters 20a-e.Reactions of 4 with 2-aminothiophenol yield the fused pyrrole and pyrrolidine derivatives 15 and 16.Compounds 20b and e were transformed to the benzothiopyranopyrrole carboxylic acid esters 23a and b.
- Eiden, Fritz,Grusdt, Ulrike
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p. 1020 - 1031
(2007/10/02)
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