0.1 Extraction of carvone  (Page 2/3)

Chiral: An object that is not superimposable on its mirror image.

Isomers: Different molecules with the same molecular formula.

Constitutional isomers: Isomers that differ in the connectivities of atoms.

Stereoisomers: Isomers that are not constitutional isomers. These differ in the spatial arrangement of atoms.

Enantiomers: Stereoisomers that are non-superimposable mirror images.

Diastereomers: Stereoisomers that are not enantiomers. (Compounds with more than one stereocenter)

Fig 2.1: Summary of isomerism

Meso Compounds: A compound that contains exactly one stereocenter is always chiral. However, compounds that contain more than one stereocenter are not necessarily chiral. This occurs when multiple stereocenters create an internal plane of symmetry. For example, consider 2,3-dichlorobutane. There are four possible stereochemical permutations since there are two stereocenters:

Figure 4: Stereoisomers of 2,3-dichlorobutane

Figure 4.2: Four possible stereoisomers of 2-bromo-3-chlorobutane

Prelab: extraction of carvone

(Total 10 Points)

On my honor, in preparing this report, I know that I am free to use references and consult with others. However, I cannot copy from other students’work or misrepresent my own data.

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1. Assign the configurations of the two stereocenters in the compound below. (2 points)

2. Assign R or S configuration to the following molecules. (3 points)

3. Between the stress of university and your diet consisting entirely of pizza, potato chips, and chocolate bars, you have developed an ulcer. In order to numb the burning in your stomach, you take Pepcid. The active ingredient in Pepcid, famotidine, has the structure shown below. For the atoms indicated, identify the hybridization (5 points)

Grading

• Completion of Pre-Lab Questions.
• Write-up in your Lab Notebook).
• Completion of Report Questions.
• TA Points.

Materials required

Safety

Wear gloves all the time. Keep safety glasses on all the time to avoid unwanted accidents. Dispose organic substances in the proper container.

Experimental procedure

1) Measure 2 g of crushed caraway seeds into a 30 mL beaker and add 10 mL of ether. Ether is chosen as a solvent because the carvone is soluble in ether. Cover with aluminum foil to prevent evaporation and allow the mixture to stand for 15-30 minutes.

2) Measure 2 g of spearmint leaves into a 50 mL beaker and add 10 mL of ether. Again, cover with aluminum foil and allow the mixture to stand for 15-30 minutes. The different containers have no effect on the extraction; they simply allow you to do two extractions simultaneously without duplicating your glassware.

3) Once the seeds have soaked for the appropriate time, use a Hirsch funnel to filter the caraway seed solution (Always clamp a filter flask.). This is done by placing a piece of filter paper in the funnel, assembling the Hirsch funnel as shown in the diagram below, and starting the suction such that a vacuum builds up in the filter flask. Pre-wet the filter paper with ether, then pipette the liquid from the extraction into the funnel and collect the liquid in the receiving flask. When you have filtered the caraway seed solution, transfer the filtrate to a cleaned 30 mL beaker and wash out the receiving flask with acetone. During filtration, if you see no solvents left at the receiving flask, you can add a minimum amount of ether (~5-10 mL) to dissolve the solid substance. Ether is volatile at room temperature.