Heterocyclic Rings Thiophene

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Presentation transcript:

Heterocyclic Rings Thiophene

Importance Pyrantal 49, is a broad spectrum anthelmintic agent (طارد للديدان المعوية) effective against pinworm and hookworm Bioten50 (Vitamin H),, occurs in yeast and egg Thiophene also occurs in organic conducting polymers

Ring Synthesis The Pall Synthesis Lawesson's reagent can be used also in this synthesis.

Applications of Lawesson’s reagent

The Hinzberg Synthesis

The Gewald Synthesis

Reactions of Thiophene Electrophilic Substitution Substitution takes place at the 2- position Reactivity pyrrole >> furan > thiophene > benzene Thiophene tends to undergo substitution rather than addition reactions and it is not so readily cleaved by acids as is furan.

Substitution of 2-substituted thiophene

Nucleophilic Substitution

Cycloaddition Reaction Thiophene is a poor diene

Diels-Alder Cycloaddition

Cycloadditions of thiophene