Evaluation of L – Proline as a Catalyst for an Asymmetric Aldol Reaction

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Evaluation of L – Proline as a Catalyst for an Asymmetric Aldol Reaction Abstract This reaction is divided into two parts. In the first part acetone, L – proline and 4 – nitrobenzaldehyde are reacted to give (R)-4-hydroxy-4-(4-nitrophenyl)butan-2-one as the major product along with (S)-4-hydroxy-4-(4-nitrophenyl)butan-2-one. The identity of the product is confirmed by IR spectra of the product which gives peaks at 1073.94 cm-1, 1330 cm-1, 1515.05, 1600.13 cm-1, 1708.25 cm-1, 2930.82 cm-1and broad peak at 3418.10 cm-1. The mass of the product is 0.013 grams which gives a percentage yield of 29.81%. The melting point of the product is not taken due to minimal product. In the second part of the reaction excess reagents are used and the…show more content…
| 53.491 | 5 mL | | | | Ethyl Acetate | 88.11 | 10 mL | 101.805 | - 83.6 | 77.1 | MgSO4 | 120.37 | | | 1124 | | CH2Cl2 | 84.93 | 4.5 mL | 70.47 | - 96.7 | 39.6 | DMAP | 122.17 | 0.0075 grams | 0.061 | 110 - 113 | 162 | Pyridine | 79.10 | 0.075 mL | 0.931 | - 41.6 | 115.2 | (-) – MTPA - Cl | 252.62 | 0.125 mL | 0.400 | | 213 – 214 | 0.1 M HCl | | 2.5 mL | | | | Sat. Bicarbonate sol | | 2.5 mL | | | | Brine | | 2.5 mL | | | | Reaction 1. Dissolve 24 mg of L – proline in 5 mL anhydrous DMSO/acetone (4:1) for 15 minutes. 2. To this solution add 60 mg of 4 – nitrobenzaldehyde and stir the mixture for at least 30 minutes. Product Isolation 3. After the reaction is complete, dilute with 5 mL of saturated ammonium chloride solution and extract the product with 10 mL of ethyl acetate. 4. Dry the organic layer over MgSO4, separate the drying agent by gravity filtration and evaporate the solvent in a rotary evaporator. Product Purification 5. Purify the product by flash chromatography using 50% petroleum

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