Experiment 5 Synthesis and NMR Spectroscopy of ethyl cinnamate
Introduction:
Wittig reactions involve the stereoselective synthesis of olefins from phosphonium ylides and aldehydes or ketones, where the carbonyl bond is converted to an alkene double bond.1 The variety of suitable reagents and the relatively mild experimental conditions facilitate their industrial applications, such as the synthesis of epoxides, esters, carotenoids and vitamin A.2,3 Specifically, the ester ethyl cinnamate is used as a flavouring agent and in perfumes.
The diastereomers of the alkene are distinguished through Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy, where the coupling constants of alkenyl protons are different for (E) and (Z) isomers.4 It is often …show more content…
A sample of this reaction mixture (100 μL) was added to dichloromethane (0.5 mL). Potassium carbonate (5 mL, 5 mmol) was added to the rest of the reaction mixture which was then placed in the sonication bath. A sample of the dichloromethane layer (100 μL) was extracted out every 8 minutes and added to dichloromethane (0.5 mL) until the 32nd minute. All the samples, along with benzaldehyde and ethyl cinnamate solutions were analysed by TLC with the eluent prepared from hexane (8 mL) and dichloromethane (2 mL), and then stained with …show more content…
The IR spectrum of this product was acquired as shown in figure 2, where the peaks were present at 3061.55 "c" "m" ^"-1" , 1707.53 "c" "m" ^"-1" , 1637.67 "c" "m" ^"-1" , 1173.41 "c" "m" ^"-1" and 734.73 "c" "m" ^"-1" . Respectively, these indicated the presence of C-H bonds on the aromatic ring and the ethyl group, the carbonyl group, the alkene bond stretches, the C-O bond of the ester and the alkene bond bends. Subsequently, the ethyl cinnamate was identified by the characteristic alkene bond and the ester
Introduction:
Wittig reactions involve the stereoselective synthesis of olefins from phosphonium ylides and aldehydes or ketones, where the carbonyl bond is converted to an alkene double bond.1 The variety of suitable reagents and the relatively mild experimental conditions facilitate their industrial applications, such as the synthesis of epoxides, esters, carotenoids and vitamin A.2,3 Specifically, the ester ethyl cinnamate is used as a flavouring agent and in perfumes.
The diastereomers of the alkene are distinguished through Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy, where the coupling constants of alkenyl protons are different for (E) and (Z) isomers.4 It is often …show more content…
A sample of this reaction mixture (100 μL) was added to dichloromethane (0.5 mL). Potassium carbonate (5 mL, 5 mmol) was added to the rest of the reaction mixture which was then placed in the sonication bath. A sample of the dichloromethane layer (100 μL) was extracted out every 8 minutes and added to dichloromethane (0.5 mL) until the 32nd minute. All the samples, along with benzaldehyde and ethyl cinnamate solutions were analysed by TLC with the eluent prepared from hexane (8 mL) and dichloromethane (2 mL), and then stained with …show more content…
The IR spectrum of this product was acquired as shown in figure 2, where the peaks were present at 3061.55 "c" "m" ^"-1" , 1707.53 "c" "m" ^"-1" , 1637.67 "c" "m" ^"-1" , 1173.41 "c" "m" ^"-1" and 734.73 "c" "m" ^"-1" . Respectively, these indicated the presence of C-H bonds on the aromatic ring and the ethyl group, the carbonyl group, the alkene bond stretches, the C-O bond of the ester and the alkene bond bends. Subsequently, the ethyl cinnamate was identified by the characteristic alkene bond and the ester