Question

Draw a FULL reaction mechanism for the formation:

reactants: sodium saccharin with iodoethane in the solvent DMF

a) N-ethylsaccharin

b) O-ethylsaccharin

Answer 1

shen sodium saccharin is treated with lodoethane in presence of DMF as solvent to givee two products i.e Nethylsacchann and o-ethyl saccharin respectively. perly CH3 wNa + CH-H-I DME > LIN + to Emyliodige oretages accharin sod. saccharin Reaction - - -C+, H. Nethyl sacchasin mechanism :- This is nucleophilic substitution reaction Mechanism sodium saccharin will attack nucleophilically via nitrogen on ethye jadide carbon to displace iodine to get N-ethyl saccharin isomer. But if sodium saccharin undergoes conjugation with pi electons of Corbanyl group then oxygen atom of Grbonyl group will nucleophilically substitute iodine atom og jodoethane to obtain o-ethylsacchane THIN

+ iNa + 4b -NGI C -CH ₂ M₂ Methylsaccharin I e I - NGI & THE CH3 o-ethyl sacchasin
in this reaction the substrate sodium saccharin contains two nucleophilic centre one at nitrogen atom and other at oxygen atom. It means nitrogen and oxygen acts as nucleophile which attack on iodoethane nucleophilically to displace iodine to form two isomers. At thermal equilibrium out of two isomers the N- ethylsaccharin is more stable and major product than O-ethyl saccharin isomer. Iodine atom of iodoethane acts as leaving group.