Search results
Results from the WOW.Com Content Network
Maleic anhydride is a classic substrate for Diels-Alder reactions. [9] It was used for work in 1928, on the reaction between maleic anhydride and 1,3-butadiene, for which Otto Paul Hermann Diels and Kurt Alder were awarded the Nobel Prize in 1950. It is through this reaction that maleic anhydride is converted to many pesticides and pharmaceuticals.
The original rationale behind Lewis acid-catalyzed Diels–Alder reactions is incorrect, [39] [48] [49] [50] because besides lowering the energy of the dienophile's LUMO, the Lewis acid also lowers the energy of the HOMO of the dienophile and hence increases the inverse electron demand LUMO-HOMO orbital energy gap. Thus, indeed Lewis acid ...
Thus, the LUMO diene and HOMO dienophile are the frontier orbitals that interact the most strongly, and result in the most energetically favourable bond formation. [2] [7] [9] In DA INV, the LUMO diene and HOMO dienophile are very close in energy, which results in a strong bonding interaction between the two.
In industry, maleic acid is derived by hydrolysis of maleic anhydride, the latter being produced by oxidation of benzene or butane. [4] Maleic acid is an industrial raw material for the production of glyoxylic acid by ozonolysis. [8] Maleic acid may be used to form acid addition salts with drugs to make them more stable, such as indacaterol ...
The first major discovery in this area was in 1960, when Yates and Eaton reported the significant acceleration of the Diels-Alder reaction by AlCl 3 when maleic anhydride is the dienophile. [ 4 ] Early theoretical studies that depended on frontier orbital analysis established that Lewis acid catalysis operates via lowering of the dienophile's ...
It involves the formation of a diene and dienophile from a cyclohexene. It can be accomplished spontaneously with heat, or with acid or base mediation. [1] [2] In principle, it becomes thermodynamically favorable for the Diels–Alder reactions to proceed in the reverse direction if the temperature is high enough.
3-Sulfolene reacts with maleic anhydride in boiling xylene to cis-4-cyclohexene-1,2-dicarboxylic anhydride, obtaining yields of up to 90%. [4] 3-Sulfolene reacts also with dienophiles in trans configuration (such as diethyl fumarate) at 110 °C with SO 2 elimination in 66–73% yield to the trans-4-cyclohexene-1,2-dicarboxylic diethyl ester. [17]
Dimethyl maleate can be synthesized from maleic anhydride and methanol, with sulfuric acid acting as acid catalyst, via a nucleophilic acyl substitution for the monomethyl ester, followed by a Fischer esterification reaction for the dimethyl ester.