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CHEM 122: Introduction to Organic Chemistry 1) Label each of the following compounds as chiral or achiral

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CHEM 122: Introduction to Organic Chemistry 1) Label each of the following compounds as chiral or achiral. If chiral, circle all stereocenters present, draw the enantiomer, and name each structure in the pair according to IUPAC nomenclature, using appropriate R/S designation to show handedness. One of these compounds has two diastereomers. Which one? Draw them, state what the relationship between the pair of compounds you have drawn is, and name each structure in the pair according to IUPAC nomenclature, using appropriate R/S designation to show handedness. HO H H OH H2N H OH H OH O 2-amino-3-hydroxypropanoic acid 2) a) Consider 2-bromo-3-chlorobutane. How many stereoisomers are possible for this compound? Draw all stereoisomers, label each stereocenter with the appropriate R/S designation to show handedness, and indicate the relationship (enantiomers or diastereomers) between every possible pairing of compounds. Name each compound according to IUPAC nomenclature, using appropriate R/S designation to show handedness. b) Repeat this exercise for 2,3-butanediol. What is different about this compound relative to the first example? What word describes the unique stereoisomer? c) Which of the compounds in parts a) and b) above are optically active? Among these, give one example of a pair of compounds that will give a specific rotation of 0o if present in equal amounts. Imagine one of them has a specific rotation of +16.9o as a pure sample. What do you expect the specific rotation of the other to be? CHEM 122: Introduction to Organic Chemistry 1) Predict the major product of each of the following reactions or series of reactions. CH3Br NH2 NH3 (-HBr) 1) (CH3)2CHCl 2) CH3CH2Cl 3) CH3Cl CH3Br N NH2 HCl HCl N 2) Of the five starting amines given in the first problem, which two are the weakest bases? Which two are the strongest bases? Draw the structure you might expect to find at biological pH of these two strongest bases. 3) Plan a synthesis of each of the following amines, from the given starting material. Both should take three steps. N NH3 NH CHEM 122: Introduction to Organic Chemistry 1) Draw both the hemiacetal and acetal each of the following aldehyde or ketone and alcohol pairs generates in the presence of acid. H O + O CH3OH + H + HO OH HO O 2) Draw the cyclic hemiacetal each of the following compounds generates in the presence of acid. H O OH H O H OH HO H HO H H OH OH 3) Thinking backwards, what aldehyde/ketone and alcohol pairs generated the following hemiacetals and acetals in the presence of acid? OH O O H O O O 4) Draw the tautomer that exists in equilibrium with each of the following aldehydes, ketones, and enols. OH O H O O CHEM 122: Introduction to Organic Chemistry 1) Arrange the following compounds from most to least acidic. Briefly explain. F OH Br OH O F Br F O O O 2) Fischer esterification produces esters from a carboxylic acid and an alcohol. For each of the following, where an acid and alcohol are given, draw the structure of the ester which is produced; and where an ester is given, draw the structures of the carboxylic acid and alcohol required to make it. OH O H+ OH O O H+ OH O O CH3CH2OH HO H+ OH O H+ O HO OH H+ O H OH OH OH OH O 3) Fill in the missing reagents in each of the following reductions. The bottom one is tricky, requires 3 separate steps, and involves Chapter 9 as well as Chapter 10. OH O O OH O OH OH O OH OH CHEM 122: Introduction to Organic Chemistry 1) a) The following carboxylic acid derivatives may each be synthesized in one or more ways from benzoic acid, as indicated. Fill in the missing reagents. O O O O OH 2 steps O O 1 step 2 steps O 1 step N 2 steps a different 2 steps b) Where more than one method exists, what are some of the advantages and disadvantages of each one? Which one would you choose to do in lab? 2) The following ester may be hydrolyzed to its parent carboxylic acid and alcohol by two different methods. Fill in the missing reagents illustrating each method, then give some of the advantages and disadvantages of each one. Which one would you choose to do in lab? O O + 1 step O OH a different 1 step HO CHEM 122: Introduction to Organic Chemistry 1) a) Fill in the missing structural forms for each of the following monosaccharides. Name each structure. Haworth Projection (? and ?) Fischer Projection Most stable Chair conformation (? and ?) O HO H HO H H OH H OH OH OH OH H H OH OH H OH H HO OH O OH H H OH H H OH H HO b) Draw structures for the product(s) formed by reaction of each monosaccharide above with: i) CH3OH, H+ ii) 1) NaBH4 2) H2O iii) Tollens’ reagent 2) a) Make two different disaccharides by linking one unit of ?-D-glucopyranose to one unit of ?-D-allopyranose: i) with a ?-1,1-Glycosidic bond ii) with a ?-1,3 –Glycosidic bond b) Draw a structure or state “No reaction” for the product formed by addition of Tollens’ reagent to each disaccharide above. CHEM 122: Introduction to Organic Chemistry Homework 10 (Tuesday June 15): Chapter 12: Carbohydrates (4 problems) 1. Draw Fischer projections for the product formed by treating each of the following monosaccharides with sodium borohydride, NaBH4, in water. a) D-Galactose b) D-Ribose 2. Reduction of D-glucose by NaBH4 gives D-sorbitol, a compound used in the manufacture of sugar-free gums and candies. Draw a structural formula for D-sorbitol. 3. Both maltose and lactose are reducing sugars, but sucrose is a nonreducing sugar. Explain why. 4. Following is a structural formula for a disaccharide. OH HO HO OH O OH O HO O OH OH a) Name the two monosaccharide units in the disaccharide. b) Describe the glycosidic bond. c) Is this disaccharide a reducing sugar or a nonreducing sugar? d) Will this disaccharide undergo mutarotation?