Question

1. Explain why dimethyl maleate is converted in high yield to dimethyl fumarate under the conditions you used. Use thermodynamic and kinetic arguments to justify your answer.

2. How does the reaction preformed relate to the isomerization of retinal in the human eye (which enables vision).
   Primer: A major topic covered in the second half of Organic I is the properties and reactivity of alkenes. This lab experiment will provide you with an opportunity to examine alkene reactivity by conducting an isomerization of dimethyl maleate to dimethyl fumarate. Interestingly, the dimethyl fumarate product is currently marketed as a prescription for relapsing multiple sclerosis. b oló Brz (catalytic) visible light dimethyl maleate dimethyl fumarate Chemical Formula: CH04 Chemical Formula: C8H304 Molecular Weight: 144.1260 g/mol Molecular Weight: 144.1260 g/mol Melting point: -17 °C Melting point: 103.5 °C density: 1.15 g/ ml Bromine is used in this reaction as a source of radicals to facilitate rupture of the bond, thereby allowing the isomerization to proceed. Unlike previous reactions that we have done, this reaction will conducted in a test tube that is heated while being irradiated with visible light. Both heating and irradiation are needed to overcome the kinetic barrier and accomplish the isomerization in a reasonable amount of time.
   

Answer 1

Dimethyl mareate is converted to dimethyl Sumarate in high yield. Hore thermodynamic stability occurs. When a system in its lowest energy state of chemical equilibrium where individual ayoms or molecules change forms but their overall number in a perly comar foom is conserved. Here dimethyl maleate is zo isomer. This Isomer is not stable. It will react in presence of Br. 4 ger converted to a more stable dimethyl sumarate. When a compound with low stability get converted to compound with high stabilly, this is called as thermo- dynamic stability. It is a spontaneous change once the molecule is get converted to more Istable isomer then it is nor converted back to starting compound kinetically stable compounds are generally intermediates which are difficult to isolates. Kinetically stable compounds are generally studied of that pesticular temperature & pressure condition In giren reaction a more stable dimethyl fumare is formed as follows: ny 27B8 تدعم کام Toite 17°C Dimethyl fumarate M.P. = 103.5 (Thermodynamically more stable)