Oxazolone TEMPLATE

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Feb 20, 2024

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TEMPLATE: Oxazolone Synthesis Please make a copy before editing. Name: Olivia Mertes Section: TA First Name: Sepi, Moha TA email: abbais@iastate.edu Combination: 38-14-28 Pre-lab Questions Day 1: Hippuric Acid Synthesis 1. (4 pts) The first synthesis for this experiment is shown below. Examine the product of the reaction. Given the most common types of reactions for acyl chlorides, what type of reaction is this? (e.g. nucleophilic substitution, addition, elimination, etc.) This type of reaction is a nucleophilic substitution since the lone pairs in the nitrogen will attack the carbonyl and the chlorine will be kaicked off. 2. (4 pts) Consider the structure of glycine at various pHs as shown below. Explain why the addition of NaOH is necessary to facilitate the reaction between benzoyl chloride and glycine. The addition of NaOH is necessary to facilitate the reaction between benzoyl chloride and glycine since we want glycine to act as the nucleophile instead of the base in the reaction. The lone pair on the nitrogen needs to be there so that it can attack the carbonyl of the benzoyl chloride. It the reaction did not have NaOH the amine group would be protonated and the lone pairs on notrogen wouldn’t be there and thereofr wouldn’t attack the carbonyl aand a whole different product would form.
3. (16 pts) Draw the complete mechanism for the reaction between benzoyl chloride and glycine. 4. (20 pts) Fill in the following tables with amounts to use. Amounts for Synthesis of Hippuric Acid Reactant Reactant Base Acid Product benzoyl chloride glycine NaOH (aq) conc HCl (aq) hippuric acid Moles 2.5 mmol 2.5 mmol 3x excess Enough to neutralize NaOH 2.5 mmol MW 140.57 g/mol 75.07 g/mol NA NA 179.17 g/mol Concentration NA NA 6 M 12 M NA Amount 0.35g 0.19g 1.25mL 0.625mL 0.448g Benzoyl chloride: 0.0025mol x 140.57g/mol = 0.35g Glycine: 0.0025mol x 75.07g/mol = 0.19g NaOH: 0.0075mol / 6M = 1.25mL HCl: 0.0075mol / 12M = 0.625mL Hippuric Acid: 0.0025mol x 179.17g/mol = 0.448g Day 2: Oxazolone Sythesis Mechanism The reaction of hippuric acid and an aromatic aldehyde to produce a fluorescent oxazolone has multiple steps. These questions will walk you through the steps. 1. (4 pts) The first step is simply a proton transfer. Fill in the missing curved arrows and draw product A to complete the step. 2. (4 pts) The second step is a nucleophilic attach on the anhydride. Draw product A and fill in the missing arrows to complete the step.
3. (4 pts) The third step is loss of a leaving group. Draw product B to complete the step. 4. (4 pts) Compound B tautomerizes as shown below. Draw product B and curved arrows to show tautomerization. 5. (8 pts) Next step is a nucleophilic attack of the double bond on the carbonyl carbon of the aldehyde. This is followed by a proton transfer step to remove the charge on the oxygen. Draw the missing product C and fill in missing curved arrows to complete these two steps. 6. (4 pts) Notice that the product of the last step is a beta hydroxy ketone (circled in red below). Remember that a beta hydroxy ketone is also the product of an aldol addition. The next step in the oxazolone reaction is like an aldol condensation: Base removes a proton, a double bond is formed, and a hydroxide leaves. Using this information, draw product D and fill in missing curved arrows.
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7. (8 pts) The next step involves intramolecular nucleophilic attack to form a five membered ring. Draw the missing product E. The curved arrows are drawn for you this time. 8. (4 pts) The final step involves loss of a leaving group to form the final product, an oxazolone. Draw the missing product E and fill in missing curved arrows. Amounts 9. (16 pts) Fill in the following tables with amounts to use.
Amounts for Synthesis of Oxazolone Reactant Reactant Base Product 4-(dimethylamino)benzaldehyde Hippuric acid anhydrous sodium acetate Moles 1.4 mmol 1.4 mmol 1.4 mmol 1.4 mmol MW 149.19 g/mol 179.17 g/mol 82.03 g/mol 292.3 g/mol Amount 0.2089g 0.251g 0.115g 0.409g Reactant: (4-dimethyl): 1.4mmol = 0.0014mol x 149.19g/mol = 0.2089g Reactant (Hippuric): 0.0014mol x 179.17g/mol = 0.251g Base: 0.0014mol x 82.03g/mol = 0.115g Product: 0.0014mol x 292.3g/mol = 0.409g In-lab Notes Week 1: o Mass of benzoyl chloride: 0.3mL o Mass of glycine: 0.185g o Mass of watch glass: 22.641g o Mass of watch glass + product: 22.702g o Mass of product: 0.061g o Melting point: 185-189 degrees C Week 2: o Mass of aldehyde: 0.16mL o Mass of anhydrous sodium acetate: 0.118g o Mass of hippuric acid: 0.253g o Mass of acetic anhydride: 0.7 mL o Mass of watch glass: 24.185g o Mass of watch glass + product: 24.306g o Mass of product: 0.121g o Melting point: 140-142 degrees C Analysis and Application Questions Do not copy and paste structures or mechanisms from any source. Answers must be legible or they will not be graded. Note that there are no application questions and point structure is different due to this being a 2- day experiment. Part 1: Hippuric Acid Synthesis Data and Observations 1. (5 pts) Calculate your percent yield. Show your work for full credit.
2. (1 pts) Melting point range of crude and pure product. a. Our melting point range was 185-189 degrees 3. Copy of FTIR spectra of crude and pure product annotated with: Crude Product:
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Pure Product: a. (6 pts) Structure (3 pts ea) b. (8 pts) Peaks labeled according to functional groups in product. (4 pts ea) 4. Copy of Proton NMR spectra of product annotated with:
3 . 6 3 . 8 4 . 0 4 . 2 4 . 4 4 . 6 4 . 8 5 . 0 5 . 2 5 . 4 5 . 6 5 . 8 6 . 0 6 . 2 6 . 4 6 . 6 6 . 8 7 . 0 7 . 2 7 . 4 7 . 6 7 . 8 8 . 0 8 . 2 8 . 4 8 . 6 8 . 8 9 . 0 9 . 2 f 1 ( p p m ) - 5 0 0 0 0 5 0 0 0 1 0 0 0 0 1 5 0 0 0 2 0 0 0 0 2 5 0 0 0 3 0 0 0 0 3 5 0 0 0 4 0 0 0 0 4 5 0 0 0 5 0 0 0 0 5 5 0 0 0 6 0 0 0 0 6 5 0 0 0 7 0 0 0 0 A p r 1 2 2 0 2 3 _ 3 3 2 L S e c 5 . 3 3 . f i d O x a z o l o n e p 1 2 . 1 0 2 . 1 6 1 . 0 3 2 . 0 0 1 . 0 0 3 . 8 5 3 . 9 2 3 . 9 4 6 . 1 5 7 . 3 4 7 . 3 6 7 . 3 7 7 . 3 8 7 . 3 8 7 . 3 8 7 . 4 2 7 . 4 3 7 . 4 4 7 . 4 6 7 . 4 7 7 . 4 7 7 . 4 8 7 . 4 9 7 . 4 9 7 . 5 0 7 . 5 1 7 . 5 3 7 . 5 4 7 . 5 4 7 . 5 4 7 . 5 5 7 . 5 6 7 . 5 6 7 . 5 7 7 . 5 8 7 . 5 8 7 . 6 9 7 . 7 0 7 . 7 1 7 . 7 1 7 . 7 2 7 . 8 6 7 . 8 7 7 . 8 7 7 . 8 8 7 . 8 8 7 . 8 9 7 . 8 9 7 . 9 4 7 . 9 4 7 . 9 6 8 . 8 2 8 . 8 3 8 . 8 5 a. (3 pts) Structure b. (7 pts) Prediction table showing shift, integrations and splitting c. (5 pts) Each peak labeled with associated proton(s) in structure Analysis 5. Explain how your data give evidence that you synthesized the product that you expected and that it is pure. a. (3 pts) Compare melting point with what was expected. Comment on possible contaminants if relevant. Was the melting point improved with recrystallization? Explain.
i. Our expected melting point was 190 degrees C and we had a melting point of 185-189 degrees C for our pure product. Pur product does not show any contaminants or deviation from what we expected with our observed melting point. b. (5 pts) Compare FTIR spectrum with what was expected. Comment on possible contaminants if relevant. Was the FTIR spectrum improved with recrystallization? Explain. i. We expected the FTIR spectrums to have four relevent peaks. These peaks were N-H which is expected to show at around 3250cm^-1, O-H stretch which is supposed to appear around 3000cm^-1, a C-H stretch which is supposed to appear around 2750cm^-1 and a C=O stretch that is supposed to appear around 1750cm^-1. Our pure spectra shows all founr relevent peaks. The N-H stretch appears at around 3300cm^-1, O-H appears at about 3000cm^-1, C-H appears right under 3000cm^-1, C=O appears right about 1700cm^-1. Yes, the FTIR was improved with recrystallization as the peaks in the pure product were a lot atringer and easier to identify. This also indicated our product had little contaminates and our product is pure. c. (5 pts) Compare 1 H-NMR spectrum with what was expected. Comment on possible contaminants if relevant. i. We predicted the final product of Hippuric acid to have 5 relevent peaks. Proton A around the aromatic were expected to have a shift between 7-8ppm, integration of 3H and multiplet splitting. Our spectra shows a peak at about 7.5ppm with 3H integration and multiplet splitting. Proton B, connected to nitrgoen was predicted to habe a shift between 8-9ppm with 1H integration and triplet splitting. Our spectra shows a peak at about 8.8ppm that has 1H integration and triplet splitting. Proton C, which is the proton off of the carbon between the nitrogen and carbonyl was expected to have a shift between 3-4ppm 2H integration, and doublet splitting. Our spectra shows a peak at about 4.0ppm with 2H integration and doublet splitting. Proton D which is connected to the oxygen was predicted to have a shift between 12-13ppm with 1H integration and singlet splitting. Our spectra does not show a peak anywhere near 12ppm. Proton E whish are next to A on the aromatic ring were expected to have a shift between 7-8ppm with 2H integration and doublet splitting. Our spectra shows a peak at about 7.9ppm with 2H integration and doublet splitting. Our spectra does not show any contaminants, but it also seems to be missing a peak which indicates that our synthesis had some issues and our product is probably not as pure as it could have been. Part 2: Oxazolone Sythesis Data and Observations 6. (5 pts) Calculate your percent yield. Show your work for full credit. 7. (1 pts) Melting point range a. 140-142 degrees C 8. (4 pts) Photo of TLC plate with R values calculated.
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9. (1 pts) Photo of fluorescence properties of product. 10. Include an annotated FTIR spectrum of your product annotated with:
a. (3 pts) Structure b. (4 pts) Label each peak with the corresponding functional group on the structure. 11. Proton NMR spectra of your product annotated with:
2 . 5 3 . 0 3 . 5 4 . 0 4 . 5 5 . 0 5 . 5 6 . 0 6 . 5 7 . 0 7 . 5 8 . 0 8 . 5 f 1 ( p p m ) - 2 0 0 0 0 0 2 0 0 0 0 4 0 0 0 0 6 0 0 0 0 8 0 0 0 0 1 0 0 0 0 0 1 2 0 0 0 0 1 4 0 0 0 0 1 6 0 0 0 0 1 8 0 0 0 0 2 0 0 0 0 0 2 2 0 0 0 0 2 4 0 0 0 0 2 6 0 0 0 0 2 8 0 0 0 0 A p r 1 9 2 0 2 3 _ 3 3 2 L S e c 5 . 3 3 . f i d O x a z o l o n e p t . 2 3 . 0 0 1 . 9 3 2 . 1 1 1 . 9 8 0 . 9 9 1 . 9 7 1 . 9 2 2 . 4 6 2 . 4 7 7 . 2 7 7 . 2 8 7 . 3 1 7 . 3 3 7 . 3 4 C D C l 3 7 . 5 4 7 . 5 4 7 . 5 5 7 . 5 6 7 . 5 8 7 . 5 9 7 . 6 1 7 . 6 2 7 . 6 2 7 . 6 4 7 . 6 4 7 . 6 5 7 . 6 5 7 . 6 6 8 . 1 3 8 . 1 5 8 . 2 0 8 . 2 0 8 . 2 1 8 . 2 2 8 . 2 3 a. (3 pts) Structure b. (7 pts) prediction table showing shift, integrations and splitting c. (5 pts) each peak labeled with associated proton(s) in structure Analysis 12. Explain how your data give evidence that you synthesized the product that you expected and that it is pure. a. (2 pts) Compare melting point with what was expected. Comment on possible
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contaminants if relevant. a. Our expected melting point of our final product was around 149-151 degrees C. Our product had a melting point range of 140-142 degrees C. Based on the melting point, our product shows that is was decently pure as it was in the reasonable range of acceptable melting point of 10 degrees. b. (4 pts) Did the TLC plate give evidence of successful synthesis? Explain a. Our TLC plate does give evidence of a pretty successful synthesis. Our product only has one spot showing that it had no contaminants and it had a higher Rf value than 2 out of 3 of our starting materials, one matching our product Rf value which indicates evidence of a successful synthesis, but there could be some contaminants in it with the matching Rf value of one of the starting materials. c. (3 pts) Did the color and fluorescence properties give evidence of a successful synthesis of oxazolone? Explain. a. Yes, the color and flourescence properties do give evidence of a successful synthesis since we know oxazilone has flourescence properties due to its amino acid light sensitivity. Our product showed a neon yellow color and flourescent properties under the UV light which indicates a succeddful synthesis and creation of oxazolone. d. (5 pts) Compare FTIR spectrum with what was expected. Comment on possible contaminants if relevant. a. The FTIR spectra is what we expected. We expected three rlelvent peaks of our product. The first peak was a C-H stretch around 2500cm^-1, a C=O stretch at about 1750cm^-1, and a C=C stretch at right about 1500cm^-1. Our soectra shows these three relevent peaks, C-H right above 2500cm^-1, C=O right above 1500cm^-1 ans C=C right below 1500cm^-1. There do not appear to be any contaminants in our spectra. e. (5 pts) Compare 1 H-NMR spectrum with what was expected. Comment on possible contaminants if relevant. a. For our product we expected four major peaks in the NMR spectra. The first proton A the methyl group was expected to have a shift of 2-3ppm, integration of 3H and singlet splitting. Our graph shows a peak at about 2.5ppm with a 3H integration and singlet splitting. Proton B which is around the aromatic right connected to the methyl group was expected to have a shirt of 7-8ppm with 4H integration and multiplet splitting. Our spectra shows a peak at about 7.4ppm with 3H integration and multiplet splitting. Proton C which is connected to the alkene was expected to have a shihft between 4-5ppm with 1H integration and singlet splitting. Our spectra does not show a peak for proton C. Proton D which is connected to the second aromatic ring was expected to show between 7-8ppm with 5H integration and multiplet splitting. Our soectra shows a peak at about 7.6ppm with 3H integration and multiplet splitting. Our spectra shows many contaminants are present. There are peaks that are not accounted for in the product, and there are peaks we expected to be there that aren’t. Since we are missing a whole peak from our product we can conclude that our product was not synthesized correctly, and there are contaminants in our product.