SI_Chem_262_Worksheets_Reeves_Spring2011

SI_Chem_262_Worksheets_Reeves_Spring2011 - SI Chem...

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Unformatted text preview: SI Chem 262 [Professor Hixson) MWE 9:05-9:55AM SI: Kyle Reeves [SI Session: Sunday 5:45 PM—7:00PM, Tuesday 8:45PM-10:00PM] Oxidation and Reduction in Organic Molecules Oxidation and reduction is thought ofa bit differently than with metals. Often; fall charges are not present in the molecule. Thefoilowing problems are in tended to practice identifi/ing oxidation states oforganic molecules and identifi/ing redox reactions. The rules for determining the oxidation state of an organic molecule are as follows: Draw a moleculefor each ofthese oxidation states: -4, 0; and +4. For each of the following reactions, predict whether the reaction can be classified as oxidation, redaction, or neither. 0 OH HOW HO\/l\/\ OH \ H20 M + BIZ —"'—"" Br OH \ Alcohols What property of alcohols allows them to obtain F: .3351 boiling points, even when the molecular weight ofthe molecule is low? Draw: a small diagram showing how molecules might interact to justifi/ your claim. To practice nomenclature. name the follow-in g alcohols. OH OH C] ()H Are alcohols acidic or basic? What is the plfa ofwater? What is the pKa ofethanol? justifv why phenol is so acidic compared to the other alcohols. Draw the molecule and its conjugate base to supportyour argument. (3H Phenol You want to generate a solution ofethoxide ion. lfyour starting material is ethanol, which reagent migh t you use to generate this solution? Write out the reaction. Couldyou use NaOH? Reactions with Alcohols Acid-promoted Substitution of on Alcohol Draw a primary alcohol and then draw a reaction riieciianismfor what might happen if HBr is slowly dropped into the alcohol. Dehydration Reaction Now, draw a tertiary alcohol and follow throapi: with the mechanism to generate a dehydrated product Don’t forget Zaitsev’s Role for elimination! Go back and label any reactions above as 53.1 Sit-'2, El or E2. Other Reactions You Should Know Predict the product of these reactions, and iden tijj/ what kind of reaction each one is. ___+ iirsoJJilo NHECIJO? —-——-—.h- “35,041 up .1, Sl Chem 262 [Professor Hixson) M WE 9:059:55AM SI: Kyle Reeves _ [SI Session: Sunday 5:45 PM—7:00P‘Mj Tuesday 8:4—5PMw10:00PM) A common synthesis of alcohols is to use the Grignara' synthesis, You should feel comfortable predicting the products ofa Grignard reagent and an aldehyde/ketone as well as determining the starting materials ifgiuen an alcohol. Draw the mechanism for the following alcohol synth esis, Make sure to note solvents and any other reagents used throughout the reaction. bv WEI Determine the reagents from which these alcohols may have been syn thesizetl. For cases that may have more than one set ofpossihle reagen ts; note thorn all. Final Product is} DH o: I ffiifr"! . or” Foch xii“ c U # s5; ,5? Possible Reagents Ag. iii—promoted Sahatitation of an Aicohoi Draw a primary aIcohoI and then draw a reaction mechanism for what might happen if H Br is slowly dropped into the alcohol Dehydration fleaction Now; draw a tertiary alcohol and follow through with the mechanism to generate a dehydrated product. Don ’t forget Zaitsev’s Role for eliminationi Go back and label any reactions above as 5N1, SNZ, E1 or E2, Other Reactions You Should Know Predict the product ofth ese reactions, and identifi/ what kind ofreaction each one ie, Egifi3‘:(}j _ A Knjfigfiw my. _ H3584? 13.30 “a Ci; i loot“: as i; is. SI Chem 262 [Professor Hixsan} M WE 9:05-9:55AM SI: Kyle Reeves [31 Session: Sunday 5:45 PM»7:OOPM, Tuesday 8:45PM-10200PM) Oxidation and redaction is thought af a bit diflerently than with metals. Often, fall charges are net present in the molecule The fallawing problems are intended to practice identijj/ing axidatian states afarganic molecules and identifi/ing redo}: reactians. The ralesfar determining the axidatian state af an organic molecule are as follows: Draw a inalecalefar eacb af these aXidatian states: «4,: 0), and +4. Far each of the fallawing reactians, predict whether the reaction can be classified as oxidatian, redaction, ar neither; OH - O HOV/M mum—en- HOV/KA OH Akahais What praperty afaicahals ailaws them ta abtain high boiling paints, even when the maiecaiar weight of the malecaie is law? Draw a smaii diagram showing haw molecules might interact ta jastifiz year claim; Ta practice namenclatare, name the following aicaheis. OH OH O! (3H Are alcahais acidic at basic? What is the pKa af water? What is the pKa af ethanol? justiij why phenol is so acidic compared ta the other alcehaisi Draw the malecale and its canjagate base to sappartyaar argument, (3H Phenai You want ta generate a salatian afethaiiide iani Ifyaar starting material is ethane}; which reagent might you ase ta generate this saiatian? Write eat the reactian, Caaidyaa use NaOH? SI Chem 262 [Professor Hixson] M WE. 9:05-9:55AM SI: Kyle Reeves [51 Session: Sunday 5:45PM-7:00PM, Tuesday 8:45PM-10:00PM] m Name. these ethers and then predict the products efthefnllowing reactants. Nut)” /’\O/\/ --—-—-———-———r- mgr 0/\\/ W B a /\O/\ m—jM Why must ethers he handled with extreme care? What is potentially dangerous about elder bottles ofether reagents? Show n mechanism fer a possible synthesis of methyl tert—biityl ether. >L/ SI Chem 262 [Professor Hixson] MWE 9:05-9:55AM SI: Kyle Reeves [SI Session: Sunday 5:45PM-7:00PM, Tuesday 8:45PM-10:00PM) Epoxides There are two distinctly, different mechanisinsfor the catalytic addition of water to an epoxide. One is an catah/zed by a strong acid and the other is catalyzed by a strong base, Draw the mechanisms for the addition of water to these eporidesfor both an acid catalized reaction [H300 and for a base catalyzed reaction (OH). OH Acid Ca ta lyzed— Base-ca ta lyzed What is the reason for why these molecules will react with strong acid and base, but other ethers do not undergo reactions with the same reagents? Predict the epoxx'defrom which these molecules can be derived, Note the reagent (acid or base] that is used to open the ring. Predict the products of these reactions. Draw both possible products and Eden trfi/ which one(s) WEN beforrned. 0 Nu‘” OCi-lsfi is ._..........._'.__',.. 13:0“ HG! W (:‘knhydruus‘: D What wouIdyou expect ffthe HCI in the third reaction above were not anhydrous? What product mfghtyou expect, then? SI Chem 262 [Professor Hixson) M WE, 9:05-9:55AM SI: Kyle Reeves ' [SI Session: Sunday 5:45PM-7:00PM, Tuesday 8:45PM—10:00PM] Ketones and Aldeh des Practice naming thefollowing carbonyl containing molecules. ldentijy both lUPAC name and common name ifapplicable, . C i O I O H I H /J\/\ H3CJ\H Mechanisms Show the mechanism for the acid-catalyzed addition ofwater to 2-butanone. Show the mechanism for the base-catah/zed addition ofwater to 3-hexanone. What is the purpose ofa catalyst? How does a catalysis afiect theyield? How does a catalyist aflect the rate of the reaction? What kinds ofmolecules are synthesized through the addition of water to ketones? Comment on their stability and its efi‘ect on the reaction equillihrium. Hemiacetals and Acetals [nyaur awn wards. describe what a hemiacetai and an acetai are. Camment an structure. stability. arder in synthesis. etc. Generate a structure afa stable hemiacetai. Predict the products of these reactions. Draw fine! praductsfar each reaction. Ci HC‘] + t"; can “mm—h- {excess} N;I*CN' Which wauidyau expect ta have the greatest Keg when reacted with UN? Which wauidyau expect ta have the least? i M34: 0%: SI Chem 262 (Professor Hixson) M WE, 9:05-9:55AM 31: Kyle Reeves [SI Session: Sunday 5:45PM-7:00PM, Tuesday 8:45PM—10:00PM] I Carboxylic Acids State ofPortonation- Succinic acid [butanedioic acid) is an example of a dicarboxylic acid. The pKa values are pKEll: 4.2 and pKa225.6. Draw the state of the molecule at the following pH’s and the relative amount if more than one molecule exists. pH 22.0 pH = 4.2 pH = 5.0 pH = 6.6 What is the order of reactivity of the following type ofcarboxylic acid derivatives? Ester Acid Anhydride Acid Chloride Amide Draw and example ofeach type ofmolecale above. Using the general form below. write out the mechanism for the addition ofa nacleophile to the carbonyl carbon. 0 A” R X justify the reastii'i.'itye* ofeath tarboxylio atid deri'.'_:::. e drawing out the resonance structure and destrihing the justification for its :;:;._ 1:3: to the overall stability of the moieeaie. Propose a set of reagents than can be used to synthesize an amide bond. If] want to synthesize an ester from an acid anhydride, how important is it that my reagents be dry [ no water present)? Draw out any relevant mechanisms to jastijj/yoar argument. SI Chem 262 [Professor Hixsonj MWE 9:05—9:55AM 81: Kyle Reeves [SI Session: Sunday 5:45PM—7:00PM, Tuesday 8:45PM~10:00PM] Sa unification of Esters and Esterification Given the following set ofreogents ond conditions, predict the finol products ofeoch reoction. Brow out of! ofthe possible products. o “Oi—l OH _+ CI—I30H 0 O—OH Mk H20 —‘—-—hI-r —h- H+ c; 'o CH3OH —-—+—-l- HQSO4 on Fish er Esterificotion Predict the foliowing esterifl'cotion product ond show the mechonisrn for the following reoction. ' O + ' H+ NOH —"_+ OH Saponification of Esters— Prediet the products of thefollowmg reactions and show the meehom’smsfor one ofthe three. [3 O '01-! Esterification and P01 mers- Predict the monomers used in the following polymers. Assume that these ore esterr'fioo tion reactions. fl H. SI Chem 262 [Professor Hixson] MWE 9:05—9:55AM 31: Kyle Reeves [51 Session: Sunday 5:45 PEA-7:00PM, Tuesday 8:45PM—10:00PM] KetmEnol Tautomerism There are two difierent mechanisms for interconverting between an aldehyde/ketone and its enoI/enalate ion form. One of these mechanisms is acid catalyzed while the other is base- ca talyzed. Draw the mechanismsfor each using 3—methyI—2-pen tanone. 3-methyI-2-pen tanone Enolform Enolateform Acid-Catah/zeti Mechanism: Base—Catalyzed Mechanism.- Predict the possihie product(5] that would beformea' in an aide! reaction with 3—methyI-2- pentanone. Label the new bona’[s) that is/areformed in the product(s). Aldol Reaction: Predictin Rea ents and Predictin Products Predict the Products Below is a series of reagents that are mixed tag eti: er in a basic solution. Predict the product or products that are formed in each aidoi reaction. 0 HuOH -————|-— O as.) D D H + “I—u—a n30 NuOH o H 1130 Predict the Reagents Below is a series of products that are generated by mixing aldehyde and/or hetone reagents together in a basic soiution. Determine a set of possible reagents that could he used to generate the desired finai product. Naif)“ I [:0 O/JL DH NuOH t?“ W E} ago SI Chem 262 [Professor Hixson] M WE, 9:05 —9:5 5AM SI: Kyle Reeves [SI Session: Sunday 5:45 PM-7:00PM, Tuesday 8:45PM-10:00PM) Practice Problems: Aldo! Reaction;r Claisen Condensation, Michael Reactionr and the Robinson Annotation Aldo]: Determine the starting materials for each of these aldol products. a Claisen Condensation: Predict the starting materials or the productsfor each ofthe Claisen condensations below. 0 O C} F D Wet-“Ha 1. _OCH2CH3 / ~——-————#-—--—I- oer-ace3 2- 1430+ O O A + AL '1. 'OCHZCHE, / HOCHZCH3 —————-—~——:I- ongoH3 2. H30“ H oCHZGI—l3 Michael Reaction: Predict the starting materials or the products for each of the Michael reactions below. Label the new bond that is formed daring each reaction. 0 f O I o C} 0 PI": 0 0 w H300 0 H3000 coon3 Robinson Annalation: Predict the starting materials or the products for each of the Robinson annalations below. Show the state of the reaction before the Michael reaction, after the Michael reaction and following the aldol condensation. 0 Make up your own Robinson annalation reaction. Give the final stractare (following the dehydration) to someone near you and see if they can work backwards to determine the starting molecules, SI Chem 262 [Professor Hixson] M WE, 9:05-9:55AM SI: Kyle Reeves [SI Session: Sunday 5:45 PM-7:00PM, Tuesday 8:45PM-10:00PM) Carbohydrates: Cyclic Hemiacetals An importancakill to develop is to be able to go between a Fischer projection ofa carbohydrate and the representation ofa carbohydrate when it is in its hemiacecaiforrn. Practice drawing the cyclic herniacecals corresponding to the Fischer projections provided below. Identify the molecule as a (D) or (L) sugar and represent both anomers. CDH Faranose: Pyranose: Put a star next to each anomeric carbon. Identifi/ where this carbon derived from in the straight-chain sugar. Carbohydrate Chemistry: Carbohydrates in a Basic Environment Carbohydrates have the ability to interconvert. This occurs through enolute 1': -' Draw the two major carbohydrates that you would espect the molecule to cor.- :: Label them with their general name (ex. aldopen tose or ketohexosej COH H {3H H {3H UH ._...__..h + H SH H LC} H0 H CHEOH Major Product 1 Major Product 2 Now, you allow this solution to equilibrate for an extended period oftirne. Would you expect there to still only be two products? Ifyou believe there are more, propose structures for the other structures. Using the major products from the first equilibrium process above and predict the products of a reverse adol reaction. (Hint: the enol/enolateform looks a lot like the result ofa dehydrated aldol reaction. Identify the “new” carbon-carbon bond relative to the unsatura tion.) Major Product 1: Major Product 2: SI Chem 262 [Professor Hixson) M WE 9:05-9:55AM SI: Kyle Reeves [31 Session: Sunday 5:45 PM-7:00PM, Tuesday 8:45PM—10:00PM] Carboh drate Chemistl‘ - Additional Practice with Stereochemistr Translate thefCIIowfngfumnCse and pyranose rings into their Fishcher projections. _ CH0 CHEOH CH0 CHEOH CH0 CHEOH CH0 CH20H Amino Acids- '|'. 1' NwTermmus 3 r5; CdTorminus "1 Zvn'tter Ion Assign the pka values to the appropriate groups on the amino acid and predict vvhat the isoelectric point (pl) vvill hefor each ofthe amino acids. 0 H H H2N———-—CH-—C—OH HgN—CH—-—C—OH I l CH2 CH2 7—0 m OH LNH ASpartic Acid (Asp, D) Histidine (His, H) pka1= 1.95, pka2= 3.71, pkafi=9.66 pkal: 1.78, pkaZ= 5.97, pka3=5.97 Perform a paper electrophoresis experiment with a pH 6 hufler solution. With a mixture ofaspartic acid, leucine and histidine. predict the final appearance of the piece of paper. The plfor leucine is 6.01. ++++ Describe the process of the Edman Degradation as vvell as the advantages and disadvantages of the process. No need to show reaction mechanism. What couldyau do to get around the limitations ofthe Edman Degradation? ...
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This note was uploaded on 09/30/2011 for the course CHEM 262 taught by Professor Hixson,s during the Spring '08 term at UMass (Amherst).

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SI_Chem_262_Worksheets_Reeves_Spring2011 - SI Chem...

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