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19_all_

Course Number: CHEM 101, Spring 2010

College/University: Duke

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19.1 (a) Write a mechanism for all steps of the Claisen condensation that take place when ethyl propanoate reacts with ethoxide ion. (b) What products form when the reaction mixture is acidified? Answer: (a) O H3CHC H COC2H5 + OC2H5 H3CHC O COC2H5 + C2H5OH H3CHC O COC2H5 O H3CH2C COC2H5 + H3CHC O COC2H5 O H3 CH2CC C2H5O H C CH3 O COC2H5 O H3CH2CC H C CH3 O COC2H5 + OC2H5 O H3CH2CC H C CH3 O COC2H5 +...

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(a) 19.1 Write a mechanism for all steps of the Claisen condensation that take place when ethyl propanoate reacts with ethoxide ion. (b) What products form when the reaction mixture is acidified? Answer: (a) O H3CHC H COC2H5 + OC2H5 H3CHC O COC2H5 + C2H5OH H3CHC O COC2H5 O H3CH2C COC2H5 + H3CHC O COC2H5 O H3 CH2CC C2H5O H C CH3 O COC2H5 O H3CH2CC H C CH3 O COC2H5 + OC2H5 O H3CH2CC H C CH3 O COC2H5 + OC2H5 O H3 CH2CC C CH3 O COC2H5 + C2H5OH O H3CH2CC C CH3 O COC2H5 O H3 CH2CC C CH3 O COC2H5 O H3CH2CC C CH3 O COC2H5 O O H C CH3 COC2H5 OH H3CH2CC C CH3 O COC2H5 H3O+ (rapid) H3 CH2CC (b) O H3 CH2CC H C CH3 O COC2H5 OH H3CH2CC C CH3 O COC2H5 and 19.2 What product would you expect from a Dieckmann condensation of diethyl heptanedioate (diethyl pimelate)? (b) Can you account for the fact that diethyl pentanedioate (diethyl glutarate) does not undergo a Dieckmann condensation? Answer: (a) Ethyl-2-oxocyclohexanecarboxylate O O COC2H5 (b) Because the four members ring is not stable. 19.3 Write mechanisms that account for the products that are formed in the two crossed Claisen condensations just illustrated. (1) O O O O H2 C C OC2H5 C OC2H5 + C H3C OC2H5 (1)NaOC2H5 (2)H3O + C Mechanism: O O Ph C H2C OC2H5 O O H2 C OC2H5 C OC2H5 C OC2H5 O C OC2H5 OC2H5 H H2C C O H2C C OC2 H5 O O O C H C H O C C OC2H5 OC2H5 H C C O O H2 C C OC2 H5 H3O+ C OC2 H5 (2) H2 C C O O O + C (1)NaOC2H5 (2)H3O+ OC2H5 O CH C OC2H5 OC2H5 C2H5O C OC2H5 Mechanism: O O C Ph O C OC2H5 CH C OC2H5 OC2H5 H O Ph C O C OC2H5 OC2H5 H CH Ph C OC2H5 H O H C Ph C H O O Ph C2H5O C OC2H5 H C C O OC2H5 OC2H5 OC2H5 O C OC2H5 CH C C O OC2H5 O OC2H5 OC2H5 19.4 What products would you expect to obtain from each of the following crossed Claisen condensations? (a) Ethyl propanoate + diethyl oxalate (b) (1)NaOCH2 CH3 (2)H3 O+ Ethyl acetate Answer: (a) O C H3C CH C O + ethyl formate (1)NaOCH2CH3 (2)H3O+ O C OC2H5 OC2H5 (b) O H C H2 C O C OC2H5 19.5 Show how you might synthesize each of the following compounds using, as your starting materials, esters, ketones, acyl halides, and so on. O O H (a) O O O O H NaOEt H 3O HCCH2CH2CH2CH2CH2 COC2 H5 O (b) O O O O NaOEt H 3O NaOEt T.M CH3 Br O CH3 CCH2 CH2CH2COEt O CO2C2 H5 (c) O CO2C2 H5 EtO OEt CH3 NaOEt H3O T.M + O O EtOOCCH2CCH2COOEt CH3 19.6 Keto esters are capable of undergoing cyclization reactions similar to the Dieckmann condensation. Write a mechanism that accounts for the product formed in the following reaction: O O O (1)NaOEt (2)H3O O CH3 C(CH2 )4COC2 H5 2-Acetyleyclopentanone Mechanism: O O (1)NaOEt (2)H3O O O CH3 C(CH2 )4COC2 H5 CH3CCHCH2 CH2CH2COC2H5 H OEt O O O OC2 H5 O CH3CCHCH2CH2 CH2 COC2H5 T.M 19.7 Occasional side products of alkylations of sodioacetoacetic esters are compounds with the following general structure: OR O H3CC CHCOC2H5 Explain how these are formed. Answer: O O O O R Br OR H3CC O CHCOC2H5 OEt OEt Na 19.8 Show how you would use the acetoacetic ester synthesis to prepare each of the following: (a) 2-pentanone , (b) 3-propyl-2-hexanone, and (c) 4-phenyl-2-butanone. Answer: (a) O O O + OEt Br (1)NaOEt/EtOH (2)H 2-pentanone (b) O O Br O + OEt (1)NaOEt/EtOH (2)H OEt O Br O (1)NaOEt/EtOH + (2)H 3-propyl-2-hexanone (c) O O O + OEt Br (1)NaOEt/EtOH (2)H 4-phenyl-2-butanone 19.9 The acetoacetic ester synthesis generally gives best yields when primary halides are used in the alkylation step. Secondary halides give low yields, and tertiary halides give practically no alkylation product at all. (a) Explain. (b) What products would you expect from the reaction of sodioacetoacetic ester and tert-butyl bromides? (c) Bromobenzene cannot be used as an arylating agent in an acetoacetic ester synthesis in the manner we have just described. Why not? a) The alkylation reaction is typical SN2 reaction. Therefore, primary alkyl halide reacts fastest, and the tertiary alkyl halide doesnt undergo SN2 at all. b) O O H H H Br Na O + sodioacetoacetic ester tert-butyl bromide O O O + c) In my thought, because Bromobenzene have a conjugation effect between benzene and bromide, it is so stable and cant be substituted so easily. 19.10 Since the products obtained from Claisen condensations are -keto esters, subsequent hydrolysis and decarboxylation of these products give a general method for the synthesis of ketones. Show how you would employ this technique in a synthesis of 4-heptanone. Answer: 19.11 In the synthesis of the keto acid just given, the dicarboxylic acid decarboxylates in a specific way, it gives O OH O O rather than OH O Explain. The answer: O O O O OH OH OH O O O O O OH O OH O O Resonance-stablized anion Forketo acid can form Enol form which is more stabilized, the acid decarboxylation occur in theposition. 19.12 How would you use the acetoacetic ester synthesis to prepare the following? O O The answer: O O O OC2H5 (1) C2H5ONa O OC2H5 O CH2Br O (2) O OH O O (1) dilute NaOH H3O heat T.M -CO2 O O O O NaOEt O H 3O + O EtOH 19.13 How would you use the acetoacetic ester synthesis to prepare the following? O O CCH2CCH3 Answer: O O O Cl O O O O NaH O 1)dilute NaOH O aprotic solvent O 2) H3O+ 3) 19.14 Outline a step-by-step mechanism for the phenylation of acetoacetic ester by bromobenzene and two molar equivalents of sodium amide. (Why are two molar equivalents of NaNH2 necessary?) Answer: O O O O O H H O O O NaNH2 Br O H NH3 NaNH2 O O O C6H5 (a) What product would be obtained by hydrolysis and decarboxylation of the acetoacetic ester? Answer: O (b) How would you prepare phenylacetic acid from malonic ester? Answer: O Cl O C2H5 O O C2 H5 + O O COOH C2H5 1) 2NaNH2 2) liq. NH3 O O C2 H5 1) dilute NaOH 2) H3+O COOH COOH 19.15 Show how you could C6H5CH2CH2COCH2COOCH2H5. Answer: use ethyl acetoacetate in a synthesis of O O O O + O Br 1) 2 NaNH /NH 2 3 O 2)NH 4Cl 19.16 Outline all steps in a malonic ester synthesis of each of the following: (a) pentanoic acid, (b) 2-methylpentanoic acid, and (c) 4-methylpentanoic acid. Answer: (a) COOCH2CH3 COOCH2CH3 COOCH2CH3 NaOCH2CH3 COOCH2CH3 COOCH2CH3 CH3CH2CH2Br H3CH2CH2C COOCH2CH3 COO OH-,heat H3CH2CH2C COO H+,heat COOH (b) COOCH 2CH 3 COOCH2CH3 COOCH 2CH 3 NaOCH2CH3 C OOCH 2CH 3 COOCH 2CH 3 CH3CH2CH2 Br H 3CH 2CH 2C COOCH2CH3 COO NaOC(CH3 )3 CH3 I H 3CH 2CH 2C COO OH-,heat H3CH2CH 2C H+,heat COO COO C OOH (c) COOCH2CH3 COOCH2CH3 COOCH2CH3 NaOCH2CH3 COOCH2CH3 COOCH2CH3 (CH3)2CHCH2Br (H3C)2HCH2C COOCH2CH3 COO OH-,heat H+,heat (H3C)2HCH2C COOH COO 19.17 The antiepileptic drug valproic acid is 2-propylpentanoic acid (administered as the sodium salt). One commercial synthesis of valproic acid begins with ethyl cyanoacetate. The penultimate step of this synthesis involves a decarboxylation, and the last step involves hydrolysis of a nitrile. Outline this synthesis. Answer: O N O O CH3CH2CH2ONa CH3CH2CH2Cl O N CH3CH2CH2ONa CH3CH2CH2Cl N O N O 1 NaOH 2 H 3O + O N HO heat CO2 O OH H 3O + 19.18 (a) Which aldehyde would you use to prepare 1,3-dithiane itself? (b) How would you synthesize C6H5CH2CHO using a 1,3-dithiane as an intermediate? (c) How would you convert benzaldehyde to acetophenone? Answer: (a) HCHO (b) S S H H (1) C4H9Li (-C4H10) (2) -LiCl S H S Cl H HgCl2, CH3OH,H2 O (-HSCH2CH2 CH2 SH) O (c) O H3O+ + HSCH2CH2CH2SH S S H (1) C4H9Li (-C4H10) (2)CH3I (-LiI) H S S O HgCl2, CH3 OH,H2O (- HSCH2CH2CH2SH) 19.19 The Corey-Seebach method can also be used to synthesize molecules with the structure RCH2CH2R. How might this be done? Answer: (1) S R' S H (1) C4H 9Li(-C4H10) (2) RCH2X(-LiX) S R' S CH2R Raney Ni (H2) R'CH2CH2R 19.20 (a) The Corey Seebach method has been used to prepare the following highly strained molecule called a metaparacyclophane. What are the structures of the intermediates A-D? 2 HSCH2CH2CH2 SH HC O CH O (1) 2 C4H9Li acid A (C14H18S4) (2) BrH2C CH2Br B (C22H24S4) Hydrolysis C (C16 H12 O2 ) NaBH4 D (C16H16O2) (1) 2 TsCl (2) 2 KOC(CH 3)3 (b) What compound would be obtained by treating B with excess Raney Ni? Answer: (a) A S S S S S S B S S C D O O HO OH (b) 19.21 How would you prepare HOCOCH2C(CH3)2CH2COOH from the product of the Michael addition given above? CH3 H3CC CH2COOC2H5 HOOC CH HOOC CH3 C CH3 H2 C O C OH H3O + CH(CO2C2H5)2 O CH3 CH2CCH2COOH CH3 heat HO C 19.22: Outline reasonable mechanisms that account for the products of the following Mannich reactions: (a) O O CH2N(CH3)2 + CH2O + (CH3)2 NH Answer: H+ H3C NH H3 C O H H3C C H OH CH3 O H3C O CH2N(CH3)2 N H3C OH H3C N + HA N CH3 O CCH3 + CH2 O + N H O CCH2CH2 N (b) Answer: H+ H NH H C O N OH N O CCH3 OH C CH2 N O CCH2CH2 N (c) OH (H3C)2 NCH2 OH CH2N(CH3)2 + 2CH2O + 2(CH3)2NH CH3 CH3 Answer: H3C NH H3C H H C O N H+ OH OH N O (H3C)2NCH2 (H3C)2NCH2 OH (H3C)2NCH2 N OH CH3 CH2 N(CH3)2 CH3 CH3 CH3 19.23 Show how you could employ enamines in systhneses of the following compounds: O O C(CH2)4CH3 (c) O CH2COCH3 (a) O (b) CH2COOC2H5 CH2CH CHCH3 (d) O Answer: Cl(a) N + O O C(CH2)4CH3 O Cl N heat O C(CH2)4CH3 H 2O C(CH)4CH3 ( b) N N O + Br CH2COCH 3 heat H2 O CH2COCH3 CH2COCH3 (c) N N O CH2CH CHCH3 + Br CH2CH CHCH3 heat H2O CH2CH=CHCH3 O CH2COC2H5 O CH2COC2H5 O (d) N Cl O N CH2COC2H5 heat H2O 19.24 Outlined here is a synthesis of phenobarvital. (a ) What are compounds A-F? (b) Propose an alternative synthesis of E from diethyl malonate. NBS CCl4 (1) Mg,Et2O (2) CO2, then H3O+ B (C8H8O2 ) SOCl2 C6H5CH3 EtOH A (C7H7Br) C (C8H7ClO) NH2CONH2 phenobarbital NaOEt D (C10H12O2) EtOCOOEt NaOEt E (C13 H16O4) KOC(CH3) CH3CH2Br F (C15H20O4) Answer: (a) A Br B O Cl OH OEt C O COOEt OEt D O Et COOEt COOEt E Phenobarbital: O F O NH Et O NH O (b) Et Et Et 1. NaOEt EtOOC COOEt 1. t-BuOK EtOOC COOEt NH2CONH2 EtOOC COOEt T. M. 2. EtBr 2. EtBr 19.25 Starting with diethyl malonate, urea, and any other required reagents, outline a synthesis of veronal and seconal. O O H EtO O O OEt + H2 N O H NH2 NaOEt N urea C2H5 O N H O NaOEt CH3CH2Br O N C2H5 N H O veronal O CH3 CH(CH2)2CH3 CH2CH CH2 EtO O O OEt NaOEt H2C CHCH2Br EtO O O OEt NaNH2 CH3 CH(CH2)2CH3 Br EtO EtO O diethyl malonate O H H2N NH2 N O CH3 CH(CH2)2CH3 CH2CH CH2 O N H O Seconal 19.26 Show all steps in the following synthesis. You may use any other needed reagents but you should begin with the compound given. You need not repeat steps carried out in earlier parts of this exercise. (a) O O O CH3CH2 CH2 COC2H5 CH3CH2CH2CCHCOC2 H5 CH2 CH3 Answer: O O O 2 CH3 CH2CH2COC2H5 NaOEt CH3CH2 CH2 CCHCOC2H5 CH2 CH3 (b) O O CH3CH2CH2 COC2 H5 Answer: O CH3CH2CH2CCH2CH2 CH3 O CH3CH2CH2 COC2 H5 (c) O CH3 CH2CH2)2 CuLi Et2O CH3CH2CH2 CCH2 CH2CH3 CH3 C6 H5CH2COC2H5 C6H5CHCO2H Answer: O CH3 C6 H5CH2COC2H5 NaOEt CH3I C6H5CHCO2H (d) O O CH3CH2CH2COC2H5 CH3 CH2CHCOC2H5 C O COC2H5 O O O CH3CH2CH2COC2H5 NaOEt C2H5OC O COC2H5 O O C CH3CH2CHCOC2 H5 COC2H5 O (e) O OO CH3CH2CH2C COC2H5 CH3CH2CH2 COC2 H5 Answer: product of (d) H 3O OO CH3CH2CH2C COC2H5 (f) O O C6H5CH2COC2 H5 C6H5CHCOC2 H5 CH O Answer: O O C6H5CH2COC2 H5 NaOEt HCOC2H5 O C6H5CHCOC2 H5 CH O (g) O O O CCH3 Answer: O O N O O CH3CCl H3O CCH3 (h) O O CH3 CCH3 O Answer: O NaOEt product of (h) (i) O O CH3 I CH3 CCH3 O O COC2H5 CH2CH3 Answer: O O O O COC2H5 NaOEt CH3CH2I CH2CH3 H 3O COOEt 19.27 Outline syntheses of each of the following from acetoacetic ester and any other required reagents. (a) tert-Butyl methyl ketone (b) 2-Hexanone (c) 2,5-Hexanedione (d) 4-Hydroxypentanoic acid (e) 2-Ethyl 1,3-butaneiol (f) 1-Phenyl-1,3-butanediol Answer: (a) O O +3 O I LDA O O O O H3O heat b O O O + O O O Br NaOEt O heat (c) O O O O O NaOEt O CH3 COCH2Br O H3 O heat O O (d) O O O O O NaOEt O BrCH2COOEt O OEt H3 O heat O OH NaBH4 O OH OH O (e) O O NaOEt + O I O O OH LiAlH4 O OH (f) O O O O O O NaOEt O PhCOCl O H 3O + Ph Ph O LiAlH4 OH OH Ph 19.28 Outline syntheses of each of the following from diethyl malonate and any other required reagents. (a) 2-Methylbutanoic acid (b) 4-Methyl-1-pentanol (c) CH3CH2CH(CH2OH)2 (d) HOCH2CH2CH2CH2OH (a) O O O O O O 1 O NaOEt O O 1. t-BuOK O O O 2 CH3CH2Br 2. CH3I H3O heat O OH (b) O O + O O Br NaOEt O O O O O H3O heat LiAlH4 OH OH (c) O O + O O Br NaOEt O O O O H3O HO O O OH LiAlH4 HO OH (d) COOEt EtOOC COOEt NaOEt COOEt BrCH2COOEt H 3O + HOOC COOEt COOH LiAlH4 HO OH 19.29 The synthesis of cyclobutanecarboxylic acid given in Section 19.4 was first carried out by William Perkin. Jr. in 1883, and it represented one of the first syntheses of an organic compound with a ring smaller than six carbon atoms. (There was a general feeling at the time that such compounds would be too unstable to exist.) Earlier in 1883, Perkin reported what he mistakenly believed to be a cyclobutane derivative obtained from the reaction of acetoacetic ester and 1,3-dibromopropane. The reaction that Perkin had expected to take place was the following: O O BrCH2CH2CH2Br + O C2 H5ONa CH2 CH2 CH2 C COC2H5 O The molecular formula for his product agreed with the formulation given in the preceding reaction, and alkaline hydrolysis and acidification gave a nicely crystalline acid (also having the expected molecular formula). The acid, however, was quite stable to heat and resisted decarboxylation. Perkin later found that both the ester and the acid contained six-membered rings (five carbon atoms and one oxygen atom). Recall the charge distribution in the enolate ion obtained from acetoacetic ester and propose structures for Perkins ester and acid. Solution: CCH3 CH3CCCH2COC2H5 O CH3 O CH3 COC2H5 COH O ester acid O 19.30 (a) In 1884 Perkin achieved a successful synthesis of cyclopropanecarboxylic acid from sodiomalonic ester and 1,2-dibromoethane. Outline the reactions involved in this synthesis. (b) In 1885 Perkin synthesized five-membered carbocyclic compounds D and E in the following way: C H O Na Br2 A (C17H28O8) 2 2 5 2 Na CH(CO2C2H5)2 + BrCH2CH2CH2Br B (C17H26O8) (1) OH /H2 O (2) H3O C (C9 H10 O8 ) heat D (C7 H10 O4 ) + E (C7H10O4) D and E are diastereomers; D can be resolved into enantiomeric forms while E cannot. What are the structures of A E? (c) Ten years later Perkin was able to synthesize 1,4-dibromobutane; he later used this compound and diethyl malonate to prepare cyclopentanecarboxylic acid. Show the reactions involved. Solution: (a) H5C2O2C Na CH(CO2 C2H5)2 + BrCH2 CH2Br CO2C2 H5 H5C2O2C CO2C2H5 H3O /H2 O HOOC COOH (b) O C2H5OC O COC2H5 O C2H5OC C2H5OC O O COC2H5 COC2H5 O CHCH2CH2CH2 CH C2H5OC O COC2 H5 O A B O HOC HOC O COH O OH O O OH O COH O O HO HO C (c) H2C O CH C H CH2 D E Br Br2 H2/Pt Br O Br O O O + Br EtONa EtOH O O O O O H3O /H2O O O O HO O OH T.M. 19.31 Write mechanisms that account for the products of the following reactions: (a) O O C6H5HC CH2(COC2H5)2 + O NaOCH2CH3 C6H5 CH CH CH2COC2H5 CHCOC2H5 C2H5O C O C O OC2 H5 (b) O O COCH3 O CH3NH2 H2C CHCOCH3 CH3 N(CH2CH2COCH3 )2 O Base N CH3 (c) CH3 H3C O CH2 COC2H5 C C2 H 5 O (-C2H5OH) CH3 O + CH3C CHCOC2H5 CH(CO2C2H5)2 CH(CO2C2 H5)2 Answer: (a) CH2(COC2H5)2 O NaOCH2 CH3 CH(CH2 OC2H5)2 O O C6 H5HC CHCOC2H5 O HO C6H5CH CH C2H5O C O H O CHCOC2H5 C6H5CH CH CH2COC2H5 C O OC2H5 C2H5O C O C O OC2H5 (b) H CH3NH H O CH3NHCH2CHCOCH3 O H2C CHCOCH3 O CH3NHCH2CH2COCH3 O H2C O CH2CH2COCH3 -OH CH3N CH2CH2COCH3 CHCOCH3 O O CH2CHCOCH3 O O COCH3 CH3N CH2CH2 COCH3 O N CH3 (c) C2 H5 OCH3 H3C O CH2COC2H5 H3C CH3 O CHCOC2H5 C C CH(CO2C2H5)2 CH(CO2C2H5)2 CH3 O + CH 3 C CHCOC2H5 CH(CO2C2H5)2 19.32 Knoevenagel condensations in which the active hydrogen compound is a-keto ester or a -diketone often yield products that result from one molecule of aldehyde or ketone and two molecules of the active methylene component. For example, R CH(COCH ) C R' O + CH2(COCH3 )2 base 32 R C CH(COCH3 )2 R' Suggest a reasonable mechanism that account for the formation of these prouducts. Answer: R C R' O R COCH3 C R' COCH3 R' CH(COCH3)2 R C CH(COCH3)2 + CH2(COCH3)2 CH(COCH3)2 19.33 Thymine is one of the heterocyclic bases found in DNA (see the chapter opening vignette). Starting with ethyl propanoate and using any other needed reagents, show how you might synthesize thymine. NH O N H O thymine Answer: O HCO2Et/NaOEt CH3CHCO2 CH2 CH3 H3 O CHO NH CH3CH2COCH2CH3 H2N H2N C O NaOEt N O H 19.34 The mandibular glands of queen bees secrete a fluid that contains a remarkable compound O known as queen substance. When even an exceedingly small amount of the queen substance is transferred to worker bees, it inhibits the development of their ovaries and prevents the workers from bearing new queens. Queen substance, a monocarboxylic acid with the molecular formula C10H16O3, has been synthesized by the following route: Cycloheptanone (1) CH3MgI (2) H3O A(C8 H16O) HA,heat B (C8H14) (1) O3 (2) Zn,HOAc C (C8H14O2) CH2 (CO2H)2 pyridine queen substance (C10H16O3) On catalytic hydrogenation queen substance yields compound D, which, on treatment with iodine in sodium hydroxide and subsequent acidification, yields a dicarboxylic acid E; that is, Queen substance H2 Pd D (C10H18O3) (1) I2 in aq.NaOH (2) H3O E (C9H16O4) Provide structures for the queen substance and compounds AE. Answer: HO CH3 C: OHC(CH2)5COCH3 A: B: D: HOOC(CH2)7COCH3 E: HOOC(CH2)7COOH queen substance: HOOC (CH2)5COCH3 19.35 Linalool, a fragrant compound that can be isolated from a variety of plants, is 3,7-dimethyl-1,6-octadien-3-ol.Linaool is used in making perfumes, and it can be synthesized in the following way: C C CH2 sodioacetoacetic H2C H F (C5H9Br) + HBr ester CH3 G C11H18O3 (1) dilute NaOH (2) H3O (3) heat H C8H14O (1) LiC (2) H3O CH I linalool linldar's catalyst Outline in the reaction involved. Answer: (1) C10H16O H 2C C CH3 C H CH2 H2 + HBr H 3C C CH3 C H H2 C Br O H3C C CH3 C H H2 C Br sodioacetoacetic H3C C CH3 ester O C H H2 C O H C CCH3 (2) COCH2CH3 O (3) H3C C CH3 C H H2 C O H C (1) dilute NaOH CCH3 H3C (2) H3O (3) heat O C CH3 C H H2 C H2 C CCH3 COCH2 CH3 (4) OH C CH3 C H H2 C H2 C HC CCH3 C H3C C CH3 C H H2 C H2 C CCH3 (1) LiC (2) H3 O CH H3 C (5) OH OH H3C C CH3 C H H2 C H2 C HC H2 CCH3 C H3C linldar's catalyst C CH3 C H H2 C H2 C H2 C CCH3 CH 19.36 Compound J, a compound with two four-membered rings, has been synthesized by the following route. Outline the steps that are involved. NaCH(CO2C2H5)2 + BrCH2 CH2CH2Br (1) LiAlH4 HBr (2) H2O C6 H12 O2 (C10H17BrO4) NaOC2 H5 C10H16O4 C6 H10Br2 CH2(CO2C2H5)2 2 NaOC2H5 C13H20 O4 Solution: (1) OH-,H2O (2) H3O+ C9H12O4 heat J (C8H12O2) + CO2 O C O C2H5 NaCH(CO2C2H5)2 + BrCH2CH2CH2Br Br C O H2 C O C2H5 O C O C2H5 OH NaOC2H5 C O O C2H5 (1) LiAlH4 (2) H2O C H2 OH HBr O H2 C Br C O C2H5 C H2 Br CH2(CO2C2H5)2 2 NaOC2H5 C O O O C2H5 (1) OH-,H2 O (2) H3O+ O C OH heat C O OH C OH + CO2 19.37 When an aldehyde or a ketone is condensed with ethyl -chloroacetate in the presence of sodium ethoxide, the product is an ,-epoxy ester called a glycidic ester. The synthesis is called the Darzens condensation. R' C R O O + ClCH2CO2C2 H5 R' C2 H5 ONa R C CHCO2C2 H5 + NaCl + C2H5OH (a) Outline a reasonable mechanism for the Darzens condensation. (b) Hydrolysis of the epoxy ester leads to an epoxy acid that, on heating with pyridine, furnishes an aldehyde. What is happening here? R' R C O CHCOOH R' O CH + CO2 C5H5N heat R C H (c) Starting with -ionone (Problem 17.15), show how you might synthesize the following aldehyde. (This aldehyde is an intermediate in an industrial synthesis of vitamin A.) CH O Answer: (a): OC2H5 H ClCH CO2C2H5 Cl R C O O HCC R' R' OC2H5 R C O CO2C2H5 R C O CHCO2C2H5 Cl R' (b): R' R C O O CHCO H N R R' C O H C C O R H N O O R' H R R' C H O CH (c): O C2H5ONa ClCH2CO2C2 H5 O CO2 C2H5 O CO2H CHO C 5H 5N heat CHOH 19.38 The Perkin condensation is an aldol-type condensation in which an aromatic aldehyde (ArCHO) reacts with a carboxylic acid anhydride(RCH2CO)2O, to give an ,-unsaturated acid (ArCH=CRCO2H). The catalyst that is usually employed is the potassium salt of the carboxylic acid (RCH2CO2K). (a) Outline the Perkin condensation that takes place when benzaldehyde reacts with propanoic anhydride in the presence of potassium propanoate. O OH O O H O + (CH3CH2CO)2O OH O O O H 3O + O OH + CH3CH2COOH (b) How would you use a Perkin condensation to prepare p-chlorocinnamic acid, p-ClC6H4CH=CHCO2H? Cl2 FeCl3 Cl + (1) O Cl ; O + H Cl AlCl3 Cl H (2) ; O H H + (CH3CO)2O Cl H2 O Cl O + CH3 COOH H (3) . 19.39 (+)-Fenchone is a terpenoid that can be isolated from fennel oil. ()-Fenchone has been synthesized through the following route. Supply the missing intermediates and reagents. CO2CH3 CH2=CHCH=CH2 (a) CO2CH3 (1) (b) (2) (c) (d) mixture of (e) and (f) CO2CH3 CO2CH3 CO2H CO2CH3 (g) (h) (i) (j) O O CO2CH3 H3 O+ CH2 CO2CH3 OH (l) (k) heat COOCH3 O (m) (n) CH2 CO2CH3 O Answer: (a) CH2=C(CH3)CO2CH3 + (b) KMnO4 OH H3O (c) EtOH, H + + (d) CH3ONa H3O (e) and (f) CO2CH3 CO2CH3 H3CO2C O O CO2CH3 (g) (h) (i) (j) (k) OHH3O+, CH3 OH Zn, BrCH2COOMe CO2CH3 CHCO2CH3 (l) H2 Pt + (m) CH3ONa H3O (n) NaNH2 CH3I 19.40 Outline a synthesis of the analgesic Darvon (below) starting with ethyl phenyl ketone. CH3 H2 C C O C O C H H2 C H2 C N(CH3)2 CH3 Answer: O O C O C2H5 CH3 C CH H3C H2 C N CH3 CH3 HO CH2Ph C N CH3 CH3 CH3 1. PhCH2MgBr 2. H3O+ + H H + HN CH3 CH3CH2COO C CH2Ph CH3 N CH3 CH3 (CH3CH2CO)2O 19.41 Explain the variation in enol content that is observed for solutions of acetylacetone (2,4-pentanedione) in the several solvents indicated. Solvent % Enol H2O 15 CH3CN 58 C6H14 92 Gas phase 92 Answer: O C O C C H2 CH3 OH C O C O C OH C C H CH3 O C O C C H CH3 H3C H3C H3C C CH3 H In a polar solvent, such as water, the keto form is stabilized by solvation. When the interaction H3C with the solvent becomes minimal, the enol form achieves stability by the internal hydrogen bonding. 19.42 When a Dieckmann condensation is attempted with diethyl succinate, the product obtained has the molecular formula C12H16O6. What is the structure of this compound? Answer: O OC2H5 C2 H5O O 19.43 Ethyl crotonate, CH3CH=CHCOOC2H5, reacts with diethyl oxalate, C2H5OOCCOOC2H5, to form a Claisen-type condensation product. O C2H5OC O CCH2CH O CHCOC2H5 Write a detailed mechanism for the formation of this compound. O H2C H C H C H COC2H5 H2C C H C H O C OC2H5 EtOH2C O EtO C O C OEt O C H O O C H C OC2H5 C2H5OC C H O C OC2H5 O CHCOC2H5 CCH2CH OEt H2 C C H O C2H5 OC O CCHCH H O CHCOC2H5 O C2H5OC O C H C C H C H O COC2H5 EtO- O C2H5 OC O CCH CHCH O COC2H5 O C2H5OC O C C H C H C H O COC2H5 O C2H5OC O C H C C H C H O COC2H5 O O CCH2CH O CHCOC2 H5 H3O+ C2H5OC 19.44 Show how this diketone could be prepared by a condensation reaction: O O Answer: O COOEt O CH3COOEt NaH COOEt CH2 COOEt NaH COOEt H 3O T.M. COOEt O 19.45 (a) Deduce the structure of product A, which is highly symmetrical. N O + A ethanol The following are selected spectral date for A: MS (m/z): 220(M.+) IR (cm-1): 2930, 2860, 1715 1 H NMR (): 1.25(m), 1.29(m), 1.76(m), 1.77(m), 2.14(s), 2.22(t); (area rations 2:1:2:1:2:2, respectively) C NMR (): 23 (CH2), 26 (CH2), 27 (CH2), 29 (C), 39 (CH), 41 (CH2), 46 (CH2), 208 (C) (b) Write the mechanism that explain formation of A. answer: (a) O O 13 (b) N O N O + O O O O O O ethanol O O NaoEt ethanol HO O O ethanol

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Duke - CHEM - 101
20.1 Outline a procedure for separating hexylamine from cyclohexane using dilute HCl, aqueous NaOH, and diethyl ether. Answer:organic phase: CH3(CH2)5NH2 dil HCl ether NaOH ether organic phase dry distill CH3 (CH2 )5NH2 dry distillaqueous phase20.2 Out
Duke - CHEM - 101
22.1 How many stereocenters are contained in the (a) aldotetrose and (b) ketopentose just given? (c) How many stereoisomers would you expect from each general structure?O CH CHOH CHOH CH2OHCH2OH C CHOH CHOH CH2OH OAn aldotetroseA ketopentoseThe answe
Duke - CHEM - 101
23.4 Give structural formulas for the products that you would expect from the following reactions:(a) -Pinene+ hot KMnO4(b) ZingibereneH+ H2PtH(c) CaryonphylleneCH 3+ HCl(d) -Selinene Answer:OH+ 2THF:BH3 (2)H2O2,OH(a)H(b)CH3ClHHCl(c
Duke - CHEM - 101
24.1 What form of glutamic acid would you expect to predominate in: (a) strongly acidic solution? (b) strongly basic solution? (c) at its isoelectric point (pI 3.2)? (d) The isoelectric point of glutamine (pI 5.7) is considerably higher than that of gluta
Duke - STAT - 101
Chapter 8 Hypothesis TestingSection 83z Test for a MeanChapter 8 Hypothesis TestingSection 83A report in USA TODAY stated that the average age of commercial jets in the United States is 14 years. An executive of a large airline company selects a samp
Duke - STAT - 101
Chapter 3 Data DescriptionSection 3-2 Measures of Central TendencyChapter 3 Data DescriptionSection 3-2 Exercise #361, 11, 1, 3, 2, 30, 18, 3, 7 The data above are the num er of b burglaries reported for a specific year for nine w stern Pennsylvania u
Duke - STAT - 101
Chapter 4 Probability and Counting RulesSection 4-2 Exercise #13 Sample Spaces and ProbabilityIf two dice are rolled one time, find the probability of getting these results. a. b. c. d. e. A sum of 6 Doubles A sum of 7 or 11 A sum greater than 9 A sum l
Duke - STAT - 101
Chapter 5 Discrete Probability DistributionsSection 5-2 Probability DistributionsChapter 5 Discrete Probability DistributionsSection 5-2 Exercise #19The probabilities that a patient wll have 0, 1, 2, or 3tests i 6531 perform d on entering a hospital a
Duke - STAT - 101
USING THE Z-TABLE Ex. 1) Find the area under the normal distribution curve. Between z=0 and z=0.75 Start by drawing the standard normal curve and shading the desired area. The shaded area looks like that in the chart. So, our answer will be the value we l
Duke - STAT - 101
Chapter 4: Probability & Counting RulesProbability: Probability is a likelihood or chance that a certain thing will happen. The thing that is happening is known as the outcome. Events are a set of possible outcomes. When tend to refer to the probability
Duke - STAT - 101
Chapter 5:Discrete Probability DistributionsWhat is a probability distribution? Probability Distribution gives all the possible outcomes and the probabilities associated with each. There are two (2) types of probability distributions. We have discrete a
Duke - STAT - 101
CHAPTER 6Ch 5 discusses discrete distributions. Ch 6 discusses a popular continuous distribution called the Normal distribution. Normal Distribution is a symmetric continuous distribution about the mean, . It is not the only symmetric continuous distribu
Duke - STAT - 101
WARNING: Due to the mere fact that we are covering chapter 10 before chapters 5-9, we will have to do a little creative editing. You will have to pay close attention to what is being covered in the notes and compare it to that in the text.Chapter 10INTR
Duke - STAT - 101
Chapter 1StatisticsWhat is it?the science of conducting studies to collect, organize, summarize, analyze, and draw conclusions from data (pg 4) statistics are used to describe or make inferences regarding a particular group or population.Why study it?
Duke - STAT - 101
Chapter 3: Data Descriptions In statistics, we like to describe what the data is telling us. It is important to distinguish between a statistic and a parameter. A statistic is obtained from a sample. A parameter is obtained from a population. We use bot
Duke - STAT - 101
USING THE Z-TABLE Ex. 1) Find the area under the normal distribution curve. Between z=0 and z=0.75 Start by drawing the standard normal curve and shading the desired area. The shaded area does not look like that in the chart. The chart will give from nega
Duke - STAT - 101
CHAPTER 7 INTRODUCTION TO CONFIDENCE INTERVALSWe now begin our study into inferential statistics. We are going to use statistics to infer what the data is telling us. In order to do so, we will use the normal approximation to the binomial, normal distrib
Duke - STAT - 101
HYPOTHESIS TESTING BACKGROUNDWhen most people think of inferential statistics, they think of hypothesis testing. Hypothesis tests are used to determine whether or not a drug is effective, whether a particular teachers students score better on the final t
Duke - STAT - 101
1 Population Hypothesis Test Flow ChartWhat are we testing?MeanIsProportionsDoes the normal approx. apply?known?VarianceYES, x z=NO Isn 30 ?n x zNO We will not discuss. NO x2 =(n 1) s 2 < < x + z 2 n 2 n t=2< 2 < (n 1) s 2(n 1) s 22 2
Duke - STAT - 101
Hypothesis Testing Steps1. 2. 3. 4. 5. Determine Ho and H1. Determine the test statistic / test value using the flow chart. * Determine the decision rule. Make a decision Write a conclusion. z Critical Value 0.10 Value 1.28 0.05 1.645 0.025 1.96 0.01 2.3
Duke - PHIL - 101
Theatre 101I.Worksheet 1general terms/conceptsArt: makes order out of chaos; man-made, therefore artificial. Fine Art: art made for entertainment, culture; brings us pleasure, sharpens our perception of life. All art requires knowledge, study and expe
Duke - PHIL - 101
Theatre 10172Worksheet 2Greek Theatrepage 57 -I.Concept: Man is the measure of all things, Fate Religious ritual: to honor the Gods, Dithryambs Epic Poetry-II.Theatre: educates, sets laws, and moral standardsSponsors: private enterprise along wit
Duke - PHIL - 101
Theatre 101Concept/Lifestyle:Worksheet 4Blood thirsty, competitive-Roman TheatreVariety entertainmentCompetitive arenaReligious ritual: to honor Gods, new Gods inventedTheatre: variety entertainment, comedy of characterSponsors: GovernmentAudience: f
Duke - CHEM - 201
Organic Chemistry I Exam 4 20101 Name KEYMultiple Choice - Circle the letter of the best choice for the answer to the question. (2 1/3 Points each) 1. The correct IUPAC name for the following compound is:BrA) 2-Bromo-4-methylenehexane C) E) 2-(2-Bromop
Duke - CHEM - 202
Organic Chemistry IDr Luke A. BurkeOrganic chemistry is the chemistry of Carbon and its compounds. For many scientists, the study of Organic Chemistry will be their only opportunity to explore synthesis. All sciences use analysis where ideas or things a
Duke - CHEM - 202
Structure and Properties of Organic Molecules Electrons exhibit wave-particle duality. 1) The particle property gives a meaning of here at this spot at this time and going off in a particular direction with a certain speed (billiard ball). Localized desri
Duke - CHEM - 202
Alkanes Alkanes are the simplest organic molecules, they only contain C and hydrogen, and only contain single bonds. Compounds that have the maximum number of bonded hydrogens, are said to be saturated. Alkanes are saturated hydrocarbons. General Formula:
Duke - CHEM - 202
The Study of Chemical Reactions Mechanism: The complete, step by step description of exactly which bonds are broken, formed, and in which order. Thermodynamics: The study of the energy changes that accompany chemical and physical transformations. It allow
Duke - CHEM - 202
Stereochemistry This is study of the 3 dimensional arrangement in space of molecules. In organic chemistry, subtle differences in spatial arrangements can give rise to prominent effects. E.g. the isomers of butenoic acid:H HO2C CO2H H HO2C CO2Htrans iso
Duke - CHEM - 202
Alkyl Halides Alkyl halides are a class of compounds where a halogen atom or atoms are bound to an sp3 orbital of an alkyl group. CHCl3 (Chloroform: organic solvent) CF2Cl2 (Freon-12: refrigerant CFC) CF3CHClBr (Halothane: anesthetic) Halogen atoms are mo
Duke - CHEM - 202
Structure and Synthesis of Alkenes Alkenes (olefins) are hydrocarbons which have carboncarbon double bonds.H H CC H HA double bond is a bond and a bond. Double bond B.D.E. bond B.D.E. = 146 kcal/mol = 83 kcal/molTherefore B.D.E. must = 63 kcal/mol. A b
Duke - CHEM - 202
Reactions of Alkenes Since bonds are stronger than bonds, double bonds tend to react to convert the double bond into bonds+ X-Y XYThis is an addition reaction. (Other types of reaction have been substitution and elimination).Addition reactions are typi
Duke - CHEM - 202
Alkynes Alkynes or acetylenes are compounds that contain a carboncarbon triple bond. E.g.HCCH acetylene CH3CH2 C C H H3C C C CH3The triple bond results in a molecular formula of CnH2n-2 Ethane Ethene Ethyne C2H6 C2H4 C2H2 0 elements of unsaturation 1 el
Duke - CHEM - 202
Synthesis and Structure of Alcohols Alcohols can be considered organic analogues of water.HOH ROHAlcohols are usually classified as primary, secondary and tertiary.H R H primary OH R R secondary H OH R R tertiary phenol R OH OHAlcohols with the hydrox
Duke - CHEM - 202
Reactions of Alcohols Alcohols are versatile organic compounds since they undergo a wide variety of transformations the majority of which are either oxidation or reduction type reactions. Oxidation is a loss of electrons Reduction is a gain of electrons.
Duke - CHEM - 202
Infrared Spectroscopy and Mass Spectrometry Introduction It is fundamental for an organic chemist to be able to identify, or characterize, the new compound that he/she has just made. Sometimes this can be achieved by a chemical means, such as determining
Duke - CHEM - 202
Nuclear Magnetic Resonance (NMR) Spectroscopy NMR is the most powerful analytical tool currently available to an organic chemist. NMR allows characterization of a very small amount of sample (10mg), and does not destroy the sample (non-destructive techniq
Duke - CHEM - 202
Organic Chemistry II with Prof. BurkeLecture Notes Email Room Office Hours Texthttp:/camchem.rutgers.edu/~burke burke@camden.rutgers.edu Sci 114B Half-hour before and after each lecture or by appt. (a) Organic Chemistry Wade, 4th ,5th, or 6th Edition (b
Duke - CHEM - 202
Conjugated Systems, Orbital Symmetry and UV Spectroscopy Introduction There are several possible arrangements for a molecule which contains two double bonds (diene): Isolated: (two or more single bonds between them)Conjugated: (one single bond between th
Duke - CHEM - 202
Aromatic Compounds Historically, benzene and its first derivatives had pleasant aromas, and were called aromatic compounds. Structure of Benzene Kekul Structure Kekul (1866) bravely proposed that benzene had a cyclic structure with three alternating C=C d
Duke - CHEM - 202
Reactions of Aromatic Compounds Just like an alkene, benzene has clouds of electrons above and below its sigma bond framework.Although the electrons are in a stable aromatic system, they are still available for reaction with strong electrophiles. This ge
Duke - CHEM - 202
Ketones and Aldehydes The carbonyl group is of central importance in organic chemistry because of its ubiquity. Without studying the carbonyl group in depth we have already encountered numerous examples of this functional group (ketones, aldehydes, carbox
Duke - CHEM - 202
Amines Amines are derivatives of ammonia with one or more alkyl groups bonded to the nitrogen. Amines can be classified as primary, secondary or tertiary, meaning one, two and three alkyl groups bonded to the nitrogen respectively. E.g.Prim ary Am ines N
Duke - CHEM - 202
Carboxylic AcidsWhen a carbonyl carbon also bears a hydroxyl group, then these compounds are appreciably acidic, and are called carboxylic acids.O R C O-HRCO2HRCOOHCarboxylic acids are classified according to the substituent that is bonded to the car
Duke - CHEM - 202
Carboxylic Acid DerivativesCarboxylic derivatives are described as compounds that can be converted to carboxylic acids via simple acidic or basic hydrolysis. The most important acid derivatives are esters, amides and nitriles, although acid halides and a
Duke - CHEM - 202
Duke - CHEM - 202
Duke - CHEM - 202
Duke - CHEM - 202
Duke - CHEM - 202
Duke - CHEM - 201
Chapter 24 Organic ChemistryStudent: _ 1. The general formula for alkenes is A. CnH2n+2 B. C2nH2n C. CnHn+2 D. CnH2n E. CnH2n-2 2. The general formula of an alkane is A. CnH2n B. CnH2n+2 C. CnH2n-2 D. CnH2n+4 E. CnH2n-4 3. Which one of these formulas is
Norfolk - CHM - CHM-331
CalculatorPotentiometric Titration of Hydrogen PeroxideOne method of determining the concentration of a hydrogen peroxide, H2O2, solution is by titration with a solution of potassium permanganate, KMnO4, of known concentration. The reaction is oxidation
Norfolk - CHM - CHM-331
17-3 Sodium Hydroxide and Carbon Dioxide: Why it is Important to Keep Your Standard NaOH Solutions CappedDescription: A sodium hydroxide solution is added to a PET soda bottle that is filled with CO2. The bottle is quickly capped and shaken. The bottle c
Norfolk - CHM - CHM-331
Chapter 17Acid-Base Equilibria81John A. Schreifels Chemistry 212Chapter 17-1Overview Solutions of a Weak Acid or Base Acid ionization equilibria Polyprotic acids Base ionization equilbria Acid-Base properties of Salts Solutions of a Weak Acid or B
UCSB - HISTORY 10 - 101
L ucas Whelan 2/2/10 H istory 101 Yugoslavia chapter summary The question of a unified Slavic state was one that brought great d ifficulties to the Peace Conference in 1919. South Slav unity would especially be a difficult task given that several soldiers
U. Houston - BUSINESS - intb 3353
1.Matching3 MatchtheitemfromColumn1withtheBESTcorrespondingitemfromColumn2. JohnMaynardKeynes Pricespecieflowmechanism HeckscherOhlintradetheory DavidRicardo HjalmarSchacht GoldStandardregulatoryprocess Nazieconomicminister Explainedpatternsofexportspeci
U. Houston - BUSINESS - intb 3353
M ANYI ZHOU 0537955 STAT 3331 Assignment 2 Due Date: 07/16/2009 1-a) 0.815515986 b) 0.186118321 c) 0.577146515 d) 0.2241537442-a) 0.815263245 b) 0.186502944 c) 0.576809919 d) 0.224041808 3) The possibilities calculated in 1 and 2 are very similar. The di
U. Houston - BUSINESS - intb 3353
Mei-Chih Lin History 1302 Antrece. Baggett Writing Assignment 1 This essay looks at the presidency of Herbert Hoover, 31st president of the United States, and Franklin D. Roosevelt, 32nd president of the United States, and compares their presidency to the
U. Houston - BUSINESS - intb 3353
ExerCompthe Intelligent path to FitnessAuthor Date PurposerCompgent path to FitnessMei-Chih Lin Wednesday, March 25, 2009 To compare the sales of the X310 and X410 modelsMei-Chih LinExerCompthe Intelligent path to Fitnesshighest highest Region R0
U. Houston - BUSINESS - intb 3353
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U. Houston - BUSINESS - intb 3353
ViewAttempt1of1Title: Started: Submitted: Timespent: Totalscore: 1. Quiz9 April27,20091:29PM April27,20091:59PM 00:29:23 80/100=80% Totalscoreadjustedby0.0 Maximumpossiblescore:100Quiz9_Q1TheFederalReserveBankusesopenmarketoperationstodirectlyaffect: S