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Chem 334
Department of Chemistry and Biochemistry
University of Delaware
Syllabus

Organic Chemistry Lab

Office Hours: 202 LDL     M 11:00-1:00, F 3:00-4:00

            W: 831-2433     

            Fax: 831-6335   

                       

           

I will be glad to schedule other appointments (maximum 30 minutes, once a week) if additional help is needed. Tutors are also available. I will not talk with you about the course on the day of the exam. I can be reached at Douglass F. Taber

Texts: Organic Chemistry Laboratory, Bell, Clark, Taber and Rodig

Molecular Model Set

Grading: Your grade will be lab quizzes 50%, and lab book, including results, 50%. You will turn in your notebook at the end of each lab period. Your TA will grade it and return it to you promptly.

Handouts: Rather than handouts, the syllabus directs you to the original literature for your guidance.

Lab Exams: There will be no lab exams, but there will be quizzes in the labs.

Protective Equipment: Goggles are required and must be worn at all times in the laboratory. Suitable clothing must also be worn.

 

Purpose of Second Semester Lab: First semester, you learned the basic techniques of organic chemistry. This semester, you will learn to put those together to do stepwise synthesis. A key to this will be your ability to follow your reactions by TLC, and to purify your products by column chromatography.

The emphasis this semester will be on your taking individual responsibility for the work you do in the lab.

9 Week of Feb. 11th: Wittig reaction (Wittig); start benzopinacol using 200 mg of benzophenone

2 Week of Feb 18th Finish benzopinacol, including pinacol rearrangement; Beckmann J. Chem. Educ. 87: 1392 (2010) run on 300 mg cyclododecanone; set up bromomandelate (see next week) on 200 mg of cyclohexene.

3 Week of Feb 25th Bromomandelate J. Org. Chem. 72: 431 (2007) separate the two diastereomers by column chromatography; measure the optical rotation of the second diastereomer off the column. Oxidize all of the first diastereomer using the procedure of Tetrahedron Lett 46: 1651(2005), except replace PCC by Dess-Martin, follow by TLC; then reduce the crude oxidized product (ketone) with NaBH4 in ethanol. Keep the reduction cold (ice bath) and the time short. Work up the reaction, and separate the two diastereomers by column chromatography; it will mainly be the second diastereomer. Measure the optical rotation of this purified second diastereomer.

4 Week of March 4th Heterocycle synthesis: 37 A #2, 37F For both, use the scale indicated. For 37A #2, dissolve 0.9 g of guanidine carbonate and 0.5 g of sodium acetate in 2.5 mL water. Once a clear solution is achieved, add 1 mL of acetylacetone. Concentrate under a stream of compressed air until slightly cloudy, then add a few drops of water to make clear again. Then let stand and crystallize. For 37F, let the crystallization sit at least overnight.

5 Week of Mar 11th Day one: run the Heck reaction: Combine 200 mg ethyl crotonate, 200 mg iodobenzene, 200 mg triethylamine, 1.0 g tetrabutylammonium bromide, 0.5 g tetrabutylammonium acetate, 5 mg Pd acetate. Heat at 120 oC for 30 min. Ref: Angew. Che. Int. Ed. 48: 6101 (2009). While it heats, set up the Grubbs reaction J. Chem. Educ. 83: 283 (2006) with eugenol, and put it in your drawer. Cool the Heck reaction, dilute with 5% aqueous NaHSO3, extract with ethyl acetate, dry over Na2SO4, evaporate. Chromatograph on 10 gm silica gel with 2% MTBE/pet ether. The product shows a strong UV spot on TLC. Take up in CH2Cl2, add 1.5 equivalent of MCPBA, let stand one week. Day 2: To purify the Grubbs product, concentrate the reaction mixture, then chromatographon 10 gm silica gel, eluting with 100 mL each of 20% MTBE/PE, 40% MTBE/PE, and pure MTBE. The desired product comes with the pure MTBE, and has a TLC Rf of 0.15 in 40% MTBE/PE.

6 Week of March 18th  Purify the epoxide from the Heck reaction by column chromatography. Record its fragrance. ; Diazonium salts 29D 1-2-3. Try painting cloth with the diazonium salt solution, then adding the coupling agent. That should leave a bolder color after rinsing.

Spring Break

7 Week of April 1st  Sulfanilamide synthesis 39ABC. At the end of step A, go right on to step B. After step B, you can let it sit before doing step C. It is convenient to monitor ammonia coming off in step B with moist pH paper.

Start carrot reduction J. Chem Educ. 83: 1049 (2006). Use 200 mg of ketone, 250 grams (half a pound) of carrots, and 750 mL of water in a 2 L beaker or Erlenmeyer flask. Before you come to lab, cut regular carrots into 1/4 inch thick circles, or cut grocery store baby carrots in half. Stir the mixture for 90 minutes, then add 15 gm NaCl, and stir an additional 10 minutes. Decant the water, and extract it with 4 x 25 mL of EtOAc. Dry the EtOAc extract with sodium sulfate, evaporate, and chromatograph the residue on 10 gm of flash silica gel. Record the weight of the recovered ketone, and the weight of the product alcohol. Measure the rotation of the product alcohol.

8 Week of April 8th  Complete the carrot reduction. 26C Electrophilic aromatic substitution. Note that in the second line of the procedure on page 241, 2.1 g should be 2.1 mL.

11 Week of April 15th  Nucleophilic aromatic substitution 28A; Chemiluminescence 30A

12 Week of April 22nd  Chemiluminescence 30B; Clean up, check out