aspirin.pptx

Project on Aspirin by a pharmacy student.

1. O-Acetylation Reaction(Aspirin) Domain- Drug design and process chemistry Submitted by – Anurag Gupta Roll no- 1902020500025

2. Contents Acetylation Aspirin Synthesis of Aspirin Calculation Observations Uses Reference

3. Acetylation Introduction of an acetyl group ( Acetoxy group,CH 3 C=O group) into an organic chemical compound is known as Acetylation Acetylation is a chemical reaction in which a hydrogen atom is substituted for an acetyl group (CH 3 C=O group) in a compound. The products formed in acetylation reactions typically have an acetoxy  functional group . When the hydrogen atom belonging to an alcohol group replaced with an acetyl group in an acetylation reaction, an ester is formed as the product E.g.

4. O-Acetylation & N-Acetylation E.g. Amines N-acetylation A mide E.g. Alcohol/phenol O-acetylation E ster

5. Aspirin Aspirin is also commonly known by the name Acetyl salicylic acid . It’s IUPAC name is : 2-Acetoxy benzoic acid . It has the ability to reduce fever (an antipyretic), to reduce pain (an analgesic), and to reduce swelling, soreness, and redness (an anti-inflammatory agent). Aspirin is also used long-term to help prevent further heart attacks,  ischemic strokes , and  blood clots  in people at high risk. 2-Acetoxy benzoic acid

6. Synthesis of Aspirin The acetylation of salicylic acid occurs in an basic medium. Here, the basic medium (usually pyridine) aids in the detachment of the chloride from the acetyl chloride. This chloride goes on to associate with the proton liberated by the phenolic OH group (hydroxy group) of the salicylic acid molecule, resulting in the formation of hydrochloric acid. The mechanism of the acetylation reaction undergone by salicylic acid to afford aspirin and hydrochloric acid as the product . It can be noted that acetylsalicylic acid is commonly known as aspirin. Salicylic acid Acetyl chloride A spirin

7. Reaction Mechanism Salicylic acid Acetyl chloride A spirin Pyridine

8. Chemicals required Requirements Apparatus required Conical flask Beaker Stirring rod Pipette Water bath Oven Salicylic acid Pyridine Acetyl chloride Water Acetic acid

9. Procedure for synthesis of aspirin Dissolve 5 gm of salicylic acid in 3.5 mL of dry pyridine contained in a conical flask. Then without delay (since this solution if allowed to stand tends to become a semisolid mass) run in 3.75 mL of acetyl chloride adding about 1 mL of it at a time & shake the mixture continuously during the addition. Maintain the temperature b/w 50-60 C throughout the addition. Heat the mixture on a boiling water bath 5-10 min. Then after cooling pour it into a beaker containing cold water (approx. 150) with stirring continuously. The crude acetyl salicylic acid (ASPIRIN) either solidifies at once or separates as oil, which rapidly crystallizes as the stirring proceeds.

10. Crude product collected was dissolved in aqueous acetic acid in a 100mL conical flask. Warmed. Approx 30mL of hot distilled water is added to the solution. If solid separates, warm till solid dissolved completely. Solution allowed to cool down. The dried crystal is weighed together with the filter paper and watch glass. Weight is recorded. A clean and dry watch glass is measured together with a filter paper and the weight is measured and recorded. Recrystallisation Of Aspirin

11. Calculations Step-1: Find the limiting agent- Start with the balanced chemical reaction- C 7 H 6 O 3 + C 2 H 3 OCl → C 9 H 8 O 4 + HCl Step-2: Calculate the molar mass- Molar mass of 1 mole of salicylic acid = 138.121 g/mol Molar mass of 1 mole of acetyl chloride = 78.49 g/mol Step-3: Convert from grams to moles- Salicyclic acid = 5g/138.12 g/mol = 0.036 mol Acetyl chloride = 3.75g/78.49 g/mol = 0.047mol Step-4: Find the ratio of your reaction- Reaction-your reaction, Ideal reaction Divide the moles of 1 reactant with other= 0.047/0.036 = 1.3

12. Step-5. Find ideal ratio of reactant- C 7 H 6 O 3 + C 2 H 3 OCl → C 9 H 8 O 4 + HCl = 1 Step-6. Compare the above two ratio to find the limiting agent- Actual reactant 1.3 > 1 ideal Reactant 1 is in excess salicylic acid , So limiting agent is acetyl chloride Step-7. Calculating theoratical yield- Ratio of product/limiting agent = aspirin/acetyl chloride 1 mole of Acetyl chloride is forms 1mole of aspirin. Therefore,0.047 mole of acetyl chloride forms 0.047 mole of aspirin. Moles = weight / molecular weight Weight = moles × molecular weight =0.047 ×180.158 = 8.46g Theoratical yield = 8.46 g Practical yield = 7.6 g %yield = practical yield / theoratical yield ×100 = 7.6/8.46 ×100 % yield = 89.83%

13. Observations 1. Melting Point : Melting point of aspirin = 147 C 2. Rf Value: A B 2cm Solvent run 3.5cm B - Aspirin A – Salicylic acid Rf =  Distance moved by analyte / Distance moved by solvent front.   Rf= 2.0/3.5 Rf= 0.57 Mobile Phase {Hexane : Acetone = 70:30 }

14. 3. Nature: 4. Physical State: 5. : Aromatic/Aliphatic Acidic White crystal Aromatic ( Sooty flame )

15. Computational Parameter S.No . Parameter Remark 1 Chemical Structure 2 IUPAC Name 2-acetoxybenzoic acid 3 Molecular Formula C 9 H 8 O 4 4 Molecular Weight 180.16 5 Melting Point 159.410C 6 LogP & CLogP 1.21 And 1.0235 7 Polar Surface Area ( tPSA ) 63.6 8 Elemental Analysis C, 60.00; H, 4.48; O, 35.52 9 Mass Spectra (m/z) 180.04 (100.0%), 181.05 (10.0%), 182.05 (1.3%)

16. S.No . Parameter Remark 1 Physical State White or almost white, crystalline powder or colorless crystals 2 Color White or colorless 3 Odor Vinegar odor 4 Solubility Freely soluble in alcohol; soluble in chloroform and in ether; sparingly soluble in absolute ether; slightly soluble in water. 5 Nature Acidic 6 Saturation/Unsaturation Saturated 7 Aliphatic/Aromatic Aromatic 8 % Yield 89.83 9 M.P. (Determined) 147 ºC 10 R f Value 0.57 Practical Parameter

17. Uses of Aspirin To reduce fever(antipyretic). To relieve mild to moderate pain from headaches To relieve pain from menstrual periods, muscles aches. Aspirin does help the heart by thinning the blood and preventing clots from developing. Aspirin is a non-steroidal anti-inflammatory drugs,work as anti-inflammatory.

18. References Vogel’s text book of Practical Organic Chemistry Page No. 1290. Ashutosh kar ,”advanced practical medicinal chemistry", third edition, 'new age international (p)limited ,publishers', page no-79-81. Practical Organic Chemistry by Frederick George Mann and Bernard Charles Saunders  Published by Longan Inc., Fourth Edition; Page No. 110. https://labmonk.com/synthesis-of-aspirin-from-salicylic-acid-using-acetic-anhydride. PubChem Aspirin compound summary accessed 07/05/2020 Vogel’s text book of Practical Organic Chemistry , Page No. 1290. Practical Organic Chemistry by Frederick George Mann and Bernard Charles Saunders  Published by Longan Inc., Fourth Edition; Page No. 110.