February 22, 2024

Synthesis of Phenytoin from Benzil by Microwave Irradiation

Synthesis of Phenytoin from Benzil by Microwave Irradiation

BP607P Medicinal Chemistry III Practical : I Preparation of drugs Sulphanilamide * 7-Hydroxy, 4-methyl coumarin * Chlorobutanol * Triphenyl imidazole * Tolbutamide * Hexamine II Assay of drugs Isonicotinic acid hydrazide * Chloroquine * Metronidazole * Dapsone * Chlorpheniramine maleate * Benzyl penicillin III Microwave irradiation technique Synthesis of Phenytoin by Microwave * Synthesis of Aspirin by Microwave IV Drawing structures and reactions using chem draw®


To synthesise and submit phenytoin from benzil by using a microwave oven and calculate its percentage yield.


The microwave region of Electro-Magnetic spectrum light between IR irradiation and frequency corresponding to the wavelength of 1cm-1 to 1m. The organic compound can be heated by applying energy in the form of microwave high-frequency IR irradiation. The use of this technique can have substantial saving time for laboratory synthesis of drugs and chemicals.

Phenytoin is prepared by condensation of benzil and urea under reflux condensation to give the heterocyclic compound Pinnacol. When the pinnacol is treated with sodium hydroxide it’s rearrangement to produce phenytoin as sodium salt and the esterification gives phenytoin as a crude product. This reaction is completed to take place only 2 to 3 minutes of microwave irradiation.


Phenytoin Synthesis Microwave

Chemicals Required:

Benzil = 1.25g
Urea = 0.75g
NaOH (30%)= 3.75 ml
Methanol = 18.75 ml


1.25gm of benzil, 0.75gm urea, 3.75ml 30% sodium hydroxide and 18.75 ml of methanol were taken in a beaker and kept in a Microwave oven for 3 minutes.

Then it was cooled to room temperature and 50ml of water was poured, mixed well and filtered. To the filtrate con. HCl, was added to get the crude product.

Then the product was recrystallized from ethanol.

Melting Point: 295oC to 298oC




Phenytoin was synthesised and reported the following

  1. Theoretical yield =
  2. Practical yield =
  3. Percentage yield =

Third Year B Pharm Notes, Syllabus, Books, PDF Subjectwise/Topicwise

T Y B Pharm Sem VT Y B Pharm Sem VI
BP501T Medicinal Chemistry II TheoryBP601T Medicinal Chemistry III Theory
BP502T Industrial Pharmacy TheoryBP602T Pharmacology III Theory
BP503T Pharmacology II TheoryBP603T Herbal Drug Technology Theory
BP504T Pharmacognosy II TheoryBP604T Biopharmaceutics and Pharmacokinetics Theory
BP505T Pharmaceutical Jurisprudence TheoryBP605T Pharmaceutical Biotechnology – Theory
BP506P Industrial Pharmacy I PracticalBP606T Quality Assurance Theory
BP507P Pharmacology II PracticalBP607P Medicinal chemistry III Practical
BP508P Pharmacognosy II PracticalBP608P Pharmacology III Practical
BP609P Herbal Drug Technology Practical

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