Synthesis of Tolbutamide


To prepare and submit tolbutamide from p-toluene sulfonamide and calculate its percentage yield.


The synthesis of tolbutamide involves the addition reaction of p-toluene sulfonamide and butyl isocyanate in the presence of triethylamine and



  • p-Toluene Sulfonamide – 1 g
  • Butyl isocyanate – 1 g
  • Triethylamine – 1.2 ml
  • Tetrahydrofuran – 10 ml


About N-butyl isocyanate (1mmol) and triethylamine (1.2mmol) in a round bottom flask containing 10 ml of tetrahydrofuran, kept in an ice bath. To the above mixture p-toluene sulfonamide (1mmol) was added dropwise at 0oc. After completing the addition, the temperature was suddenly raised to 35-45oC and stirred for 3-4 Hrs. Then the solution was filtered. The product was separated and dried. Then it was recrystallised by using Diethyl ether.
Melting Point: 128oC to 129oC
Use: Anti-diabetic


Tolbutamide was Prepared and submitted. Report the Following
Theoretical Yield:
Practical Yield:
Percentage Yield:

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