Sách giải cuốn Organic Structures from Spectra 4th Wiley (2007)

Please Keep Absolutely Confidential ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman Copyright: Copying or duplicating these solutions in any form is strictly prohibited Solutions Manual December 2007 Please Keep Absolutely Confidential ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman Copyright: Copying or duplicating these solutions in any form is strictly prohibited BrCH2 CH2Br O 13 OH OH CH3 C C Cl2CH CH3 CH3 CH3 CH3 2-butanone 1,2-dibromoethane pinacol 1,1-dichloroethane C4H8O C2H4Br2 C6H14O2 C2H4Cl2 CH3CH2 OH 10 O CH3 O O O 14 CH3 H CH3 CH3 OH O propionic acid 1,2-butanedione (biacetyl) C4H6O2 C3H6O2 O CH2CH3 CH3 O CH2C N CH2C N 11 1,4-cyclohexanedione 2-propanol C6H8O2 C3H8O O 15 CH3 H CH3 Br ethyl acetate succinonitrile cyclopentanone 2-bromopropane C4H8O2 C4H4N2 C5H8O2 C3H7Br CH3O CH2CH3 O 12 CH3 CH3 CH3 C C CH3CH2 I 16 Cl Cl CH3 CH3 CH3 December 2007 methyl propionate 2,2,3,3-tetramethylbutane iodoethane 1,4-dichlorobutane C4H8O2 C8H18 C2H5I C4H8Cl2 Please Keep Absolutely Confidential 17 Br ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman 21 Br Copyright: Copying or duplicating these solutions in any form is strictly prohibited H2N 25 COOH N CH2C 29 CH2 C CH3 O 1,3-dibromopropane 4-aminobutyric acid benzyl cyanide benzyl methyl ketone C3H6Br2 C4H9NO2 C8H7N C9H10O 18 Br 22 Cl 26 OCH3 CH2NH2 30 O 1-bromo-3-chloropropane anisole benzylamine propiophenone C3H6BrCl C7H8O C7H9N C9H10O 19 Br N C 23 27 CH2OH OH 31 CH3 CH C H O 4-bromobutyronitrile benzyl alcohol 2-phenylethanol 2-phenylpropionaldehyde C4H6NBr C7H8O C8H10O C9H10O 28 + NH3 20 CH3 December 2007 H COO 24 OH CH2Br 32 O H CH3 - alanine benzyl bromide 1-phenylethanol butyrophenone C3H7NO2 C7H7Br C8H10O C10H12O Please Keep Absolutely Confidential ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman O 33 O O 34 37 O 41 N CH3 O C O 45 C O CH3 O CH3 H CH3 O O H t-butyl acetoacetate dibenzylamine propionic anhydride 1,1-diacetoxyethane C8H14O3 C14H15N C6H10O3 C6H10O4 CH3CH2 O C H 38 42 CH3 O CH3 N N ethyl formate CH3 O 35 O 39 C H O COOCH3 CH3 diethyl oxalate dimethyl methylmalonate C6H10O4 C6H10O4 43 O 47 O CH3 O O O CH3 O CH3 CH3 O O O C CH3OOC O N,N,N,N-tetramethyl-1,2ethanediamine C6H16N2 C3H6O2 46 O CH3 C O OCH3 benzil 2,5-hexanedione ethylene glycol diacetate methyl acetyllactate C14H10O2 C6H10O2 C6H10O4 C6H10O4 36 40 44 O CH3CH2O OCH2CH3 48 O CH3O OCH3 O December 2007 Copyright: Copying or duplicating these solutions in any form is strictly prohibited O O C C O O 1,2-diphenylethane diethyl carbonate dimethyl succinate diethyl succinate C14H14 C5H10O3 C6H10O4 C8H14O4 Please Keep Absolutely Confidential Copyright: Copying or duplicating these solutions in any form is strictly prohibited ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman O 49 53 O O 57 CHCl2 O H3C CH3 H3C CH3 61 OCH3 OCH3 OCH3 ethylene glycol dipropionate α,α-dichlorotoluene 1,2,3-trimethoxybenzene durene C8H14O4 C7H6Cl2 C9H12O3 C10H14 CH3 50 51 O O C C O 54 58 OCH3 C H OCH3 CH3 62 CH3 CH3 CH3 CH3 butyric anhydride benzaldehyde dimethylacetal mesitylene 1,2,3,4-tetramethylbenzene C8H14O3 C9H12O2 C9H12 C10H14 Br 55 Br 59 OH 63 CH3 COOH CH3 CH3 CH3 CH3 CH3 52 CH3 CH3 1,4-dibromobenzene benzilic acid 1,2,3-trimethylbenzene 1,2,3,5-tetramethylbenzene C6H4Br2 C14H12O3 C9H12 C10H14 Br Br 56 60 OH CH3 CH3 OH CH3 64 CH3 CH3 CH3 CH3 CH3 CH3 4,4'-dibromobiphenyl catechol 1,2,4-trimethylbenzene hexamethylbenzene C12H8Br2 C6H6O2 C9H12 C12H18 December 2007 Please Keep Absolutely Confidential 65 CH3 ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman 69 CH3 CH3 1,2,3,4,5,pentamethylcyclopentadiene C10H16 66 CH3 CH3 3-hydroxybutanone (acetoin) C4H8O2 70 NH2 74 4-hydroxy-4-methyl-2pentanone C6H12O2 C2H5NO 71 O O 3,3-dimethylglutaric acid C7H12O4 78 HOOC COOH O hexylamine 2,2-dimethylpentanedioc acid C7H12O4 C6H15N 75 CH3 79 O CH3CH2 O CH3 CH3 CH3 O CH3 Br N N CH3 O ethyl glycolate isobutyl acetate ethyl 2-bromopropionate tetramethylurea C4H8O3 C6H12O2 C5H9O2Br C5H12N2O 68 72 O CH3CH2O December 2007 NH2 HOOC COOH CH3 CH3 O acetamide HO CH3 CH3 2-methyl-2-butanol (t-amyl alcohol) C5H12O HO O 67 77 OH CH3 O CH3 H 73 OH CH3 CH3 Copyright: Copying or duplicating these solutions in any form is strictly prohibited C N 76 COOH OCH3 O 80 O O OCH3 ethyl cyanoacetate 3,3-dimethylbutyric acid 4,4-dimethoxy-2-butanone 1,3-dioxan C5H7NO2 C6H12O2 C6H12O3 C4H8O2 Please Keep Absolutely Confidential 81 ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman 85 O 89 Br OH O 93 CH2 HO O H O 1,4-dioxan 2-bromohexanoic acid 2-methylbut-3-en-2-ol dibutyl ether C4H8O2 C6H11O2Br C5H10O C8H18O 82 O 86 O O 90 CN H + - C H OH O O 94 NH3 CH3 CN O O 83 Copyright: Copying or duplicating these solutions in any form is strictly prohibited O 18-crown-6 2-ethylmalononitrile threonine butylbenzene C12H24O6 C5H6N2 C4H9NO3 C10H14 H2C C 87 CH2Cl 91 CN Br 95 C(CH3)3 Cl 2,3-dichloropropene 3-methylbutyronitrile 1-bromo-3-phenylpropane t-butylbenzene C3H4Cl2 C5H9N C9H11Br C10H14 84 88 O Cl O H2N C C 92 H NO2 96 CH3 4-chlorobutyl acetate 5-amino-1-pentyne 1-nitropropane sec-butylbenzene C6H11O2Cl C5H9N C3H7NO2 C10H14 December 2007 Please Keep Absolutely Confidential ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman 101 97 Copyright: Copying or duplicating these solutions in any form is strictly prohibited Cl C(CH3)3 105 O C 109 O CH3O C CH3 HO CH2OCH3 CH3 neopentylbenzene p-chloroacetophenone 4-methoxyacetophenone 4-methoxymethylphenol C11H16 C8H7OCl C9H10O2 C8H10O2 98 CH2Cl 102 CH3 O 106 O CH3 C C O 110 CH3 CH3 N C N CH3 Cl 4-(n-butyl)-α-chlorotoluene p-toluyl chloride p-cresyl acetate 4-dimethylaminobenzonitrile C11H15Cl C8H7OCl C9H10O2 C9H10N2 99 103 O CH3O 107 COOH O H3C 111 CH3 Br C N CH3 OCH3 4-methyl-4-phenyl-2-pentanone C12H16O 100 O Br C 104 p-anisic acid methyl p-toluate p-bromo-N,N-dimethylaniline C8H8O3 C9H10O2 C8H10NBr CH2O C CH3 108 CH3O CH2OH O CH3 112 O CH3O C C(CH3)3 p-bromoacetophenone benzyl acetate p-methoxybenzyl alcohol p-anisyl t-butyl ketone C8H7OBr C9H10O2 C8H10O2 C12H16O2 December 2007 Please Keep Absolutely Confidential 113 O (H3C)3C Copyright: Copying or duplicating these solutions in any form is strictly prohibited ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman 117 121 O O C CH3 CH3CH2O C H NH2 125 N O 4-t-butylphenyl acetate o-nitrobenzaldehyde ethyl p-aminobenzoate C12H16O2 C7H5NO3 C9H11NO2 (CH3)3C C OCH3 O 118 H C 122 OCH3 CH3CH2O C O NH2 p-ethoxybenzamide C12H16O2 C8H8O2 C9H11NO2 NO2 119 p-ethoxyacetanilide (phenacetin) C10H13NO2 H 126 HO N C CH3 O 4-methoxybenzaldehyde CH3O O 2N C C H 123 p-hydroxyacetanilide (paracetamol) C8H9NO2 127 O CH3 CH3 O O methyl 4-t-butylbenzoate 115 C CH3CH2O NO2 114 H O C NH C CH3 O O 116 p-nitroanisole 4-nitrophenylacetylene 4-methylacetanilide ethyl p-ethoxybenzoate C7H7NO3 C8H5NO2 C8H9NO C11H14O3 H C NO2 120 124 O C O O C H3C OH 128 O CH3 C NH2 O OCH3 O p-nitrobenzaldehyde 4-acetoxybenzoic acid 4-aminoacetophenone C7H5NO3 C9H8O4 C8H9NO December 2007 CH3O methyl (p-methoxyphenyl)propionionate C11H14O3 Please Keep Absolutely Confidential 129 H N Copyright: Copying or duplicating these solutions in any form is strictly prohibited ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman 133 137 O O O C O O O C 141 H O O CH3 C O N-isopropylbenzylamine hydroquinone dipropionate C10H15N C12H14O4 130 134 OCH3 O C CH3 methyl 2-methoxy-2phenylacetate C10H12O3 131 NCO O cyclopropyl methyl ketone C5H8O 142 CH3O C O O 138 O O 1,3-dihydroxyphenyl dipropionate C12H14O4 C C H OCH3 OH C O O O diethyl terephthalate dimethyl o-phthalate cyclopropane carboxylic acid C12H14O4 C10H10O4 C4H6O2 O 135 C C 139 O O O 143 H C O O 132 phenyl isocyanate diethyl o-phthalate cycloheptanone benzoylcylopropane C7H5NO C12H14O4 C7H12O C10H10O OCH3 136 O OCH3 H O C 140 O C 144 H CH2 C O OCH2CH3 O phenylacetaldehyde dimethyl acetal C10H14O2 December 2007 diethyl isophthalate cycloheptatriene ethyl cyclobutanecarboxylate C12H14O4 C7H8 C7H12O2 10 Please Keep Absolutely Confidential ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman Problem 301 Problem 302 1-iodobutane butyl butyrate Carbon Ha Chemical Shift (δ) in ppm 0.75 Ca Chemical Shift (δ) in ppm 13.9 Hb 1.19 Cb 19.5 Hc 1.40 Cc 31.2 Hd 3.97 Cd 64.0 Ce 172.8 Proton Hf 2.08 Cf 36.2 Hg 1.52 Cg 19.0 Hh 0.79 Ch 13.9 December 2007 Copyright: Copying or duplicating these solutions in any form is strictly prohibited 1-butanol 1-iodobutane 25 CH3 CH2 CH2 CH2 CH3 CH2 CH2 CH2 OH I 1-butanol H1 H Chemical Shift (δ) in ppm 2.70 H1 H Chemical Shift (δ) in ppm 3.41 H2 1.40 H2 1.27 H3 1.08 H3 1.39 H4 0.64 H4 0.84 -OH 1.95 Please Keep Absolutely Confidential Copyright: Copying or duplicating these solutions in any form is strictly prohibited ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman Problem 303 Problem 304 CH3 (E)- and (Z)-2-butene H C (Z)-3-methyl-2-penten-4-ynol C CH2OH C C H H Problem 305 Br C C CH3 CH3 H8 NO2 H7 H2 H6 H3 1-nitronaphthalene H5 H CH3 C CH3 December 2007 C Br 26 H4 Proton Chemical Shift (δ) in ppm H2 8.22 H3 7.53 H4 8.10 H5 7.95 H6 7.62 H7 7.71 H8 8.56 Please Keep Absolutely Confidential Copyright: Copying or duplicating these solutions in any form is strictly prohibited ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman Problem 306 Problem 309 COOCH2CH3 ethyl diethylmalonate CH3 CH3CH2 C geraniol COOCH2CH3 H CH3 HOCH2 Problem 307 butyl valerate CH3 CH2 CH2 CH2 O C CH2 CH2 CH2 CH3 O Problem 308 CH3 nerol CH3 H CH3 H December 2007 CH3 H CH2OH 27 H Please Keep Absolutely Confidential ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman Copyright: Copying or duplicating these solutions in any form is strictly prohibited Chapter 9.4 – Analysis of NMR Spectra Problem 310 Problem 311 Structure Number of 1H environments Number of 13C environments CO CH2CH2CH3 CH3CH2 CO CH2CH3 CH2 CHCH2CH3 cis- CH3CH CHCH3 2 trans-CH3CH CHCH3 2 1 3 2 slow chairchair fast chairchair 1 rigid CH3 Cl Br Chemical Shifts δA = 300 Hz / 60 MHz = 5.0 ppm δM = 240 Hz / 60 MHz = 4.0 ppm δX = 120 Hz / 60 MHz = 2.0 ppm Br Cl Cl Br Br Br Cl Cl OCH3 H Problem 312 Chemical Shifts Cl December 2007 28 δA = 180 Hz / 200 MHz = 0.90 ppm δM = 220 Hz / 200 MHz = 1.22 ppm δX = 300 Hz / 200 MHz = 1.50 ppm Please Keep Absolutely Confidential ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman Problem 313 Problem 314 Spin System Chemical Shifts Copyright: Copying or duplicating these solutions in any form is strictly prohibited A2X3 δA = 150 Hz / 400 MHz = 0.375 ppm δX = 300 Hz / 400 MHz = 0.750 ppm Chemical Shifts δA = 3.36 ppm = 3.36 x 60 = 202 Hz from TMS δX = 1.11 ppm = 1.11 x 60 = 67 Hz from TMS 1st Order Analysis ΔνAX = νA - νX = 202 - 67 = 135 Hz ΔνAX / JAX = 135 / = 19.3 This ratio is much greater than so a 1st order analysis is justified December 2007 29 Please Keep Absolutely Confidential Problem 315 Spin System Chemical Shifts Coupling constants 1st Order Analysis Copyright: Copying or duplicating these solutions in any form is strictly prohibited ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman AMX Problem 316 Spin System AMX δA = 501 Hz / 100 MHz = 5.01 ppm δM = 439 Hz / 100 MHz = 4.39 ppm δX = 408 Hz / 100 MHz = 4.08 ppm Chemical Shifts JAM = 3.1 Hz JAX = 20.1 Hz JMX = 1.1 Hz δA = 460 Hz / 60 MHz = 7.67 ppm δX = 442 Hz / 60 MHz = 7.37 ppm δM = 394 Hz / 60 MHz = 6.57ppm Coupling constants JAM = 1.70 Hz JAX = 0.85 Hz JMX = 3.65 Hz 1st Order Analysis ΔνΑΜ = νA - νM = 460 - 394 = 66 Hz ΔνΑΞ = νA - νX = 460 - 442 = 18 Hz ΔνΜΞ = νM - νX = 442 - 394 = 48 Hz ΔνΑΜ / JAM = 66 / 1.7 = 38.8 ΔνΑΞ / JAX = 18 / 0.85 = 21.2 ΔνΜΞ / JMX = 48 / 3.65 = 13.2 ΔνΑΜ = νA - νM = 501 - 439 = 62 Hz ΔνΑΞ = νA - νX = 501 - 408 = 93 Hz ΔνΜΞ = νM - νX = 439 - 408 = 31Hz ΔνΑΜ / JAM = 62 / 3.1 = 20.0 ΔνΑΞ / JAX = 93 / 20.1 = 4.6 ΔνΜΞ / JMX = 31 / 2.1 = 14.7 All ratios are greater than so a 1st order analysis is justified All ratios are greater than so a 1st order analysis is justified December 2007 30 Please Keep Absolutely Confidential Problem 317 Spin System ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman AMX Chemical Shifts δ3 = 673 Hz / 100 MHz = 6.73 ppm δ4 = 719 Hz / 100 MHz = 7.19 ppm δ6 = 777 Hz / 100 MHz = 7.77ppm Coupling constants 1st Order Analysis Δν34 = ν4 - ν3 = 719 - 673 = 46 Hz Δν46 = ν6 - ν4 = 777 - 719 = 58 Hz Δν36 = ν6 - ν3 = 777 - 673 = 104 Hz Δν34 / J34 = 46 / 8.8 = 5.2 Δν46 / J46 = 58 / 2.3 = 25.2 Δν36 / J36 = 104 / 104 Problem 318 J34 = 8.8 Hz J46 = 2.3 Hz J36 not resolved (< 1Hz) Spin System AMX Chemical Shifts δA = 628 Hz / 100 MHz = 6.28 ppm δB = 527 Hz / 100 MHz = 5.27 ppm δC = 592 Hz / 100 MHz = 5.92 ppm Coupling constants JAB = 2.1 Hz; JAC = 17.5 Hz; JBC = 9.9 Hz 1st Order Analysis ΔνAB = νA - νB = 628 - 527 = 101 Hz ΔνAC = νA - νC = 628 - 592 = 36 Hz ΔνBC = νC - νB = 592 - 527 = 65 Hz ΔνAB / JAB = 101 / 2.1 = 48.1 ΔνAC / JAC = 36 / 17.5 = 2.1 ΔνBC / JBC = 65 / 9.9 = 6.6 All ratios are greater than so a 1st order analysis is justified December 2007 Copyright: Copying or duplicating these solutions in any form is strictly prohibited out of ratios are greater than so this is borderline 1st order The main deviation from 1st order is that intensities are severely distorted - a 1st order spectrum would have all lines of equal intensity JAC = 17.5 Hz indicates that HA and HC must be trans JBC = 9.9 Hz indicates HA and HC are cis 31 Please Keep Absolutely Confidential Problem 319 Spin System Chemical Shifts Copyright: Copying or duplicating these solutions in any form is strictly prohibited ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman AX3 Problem 320 Spin System AX3 δA = 160 Hz / 60 MHz = 2.67 ppm δX = 280 Hz / 60 MHz = 4.67 ppm Chemical Shifts δA = 199 Hz / 100 MHz = 1.99 ppm δX = 99 Hz / 100 MHz = 0.99 ppm Coupling constants JAX = Hz 1st Order Analysis ΔνAX = νA - νX = 199 - 99 = 100 Hz ΔνAX / JAX = 100 / = 20.0 ΔνAX / JAX is much greater than so a 1st order analysis is justified December 2007 32 Please Keep Absolutely Confidential Problem 321 Spin System AMX2 Chemical Shifts December 2007 ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman Problem 322 δA = 340 Hz / 60 MHz = 5.67 ppm δM = 240 Hz / 60 MHz = 4.00 ppm δX = 100 Hz / 60 MHz = 1.67 ppm Spin System AM2X Chemical Shifts 33 Copyright: Copying or duplicating these solutions in any form is strictly prohibited δA = 110 Hz / 60 MHz = 1.83ppm δM = 200 Hz / 60 MHz = 3.33 ppm δX = 290 Hz / 60 MHz = 4.83 ppm Please Keep Absolutely Confidential Problem 323 Spin System Chemical Shifts Copyright: Copying or duplicating these solutions in any form is strictly prohibited ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman AM2X Problem 324 Spin System δA = 646 Hz / 100 MHz = 6.46 ppm δM = 510 Hz / 100 MHz = 5.10 ppm δX = 395 Hz / 100 MHz = 3.95 ppm Coupling constants JAM = Hz; JAX = 16 Hz; JMX = Hz; 1st Order Analysis ΔνAX = νA - νX = 646 - 395 = 251 Hz ΔνAM = νA - νM = 646 - 510 = 136 Hz ΔνMX = νM - νX = 510 - 395 = 115 Hz ΔνAX / JAX = 251 / 16 = 15.7 ΔνAM / JAM = 136 / = 45.3 ΔνMX / JMX = 115 / = 23.0 A2MX Chemical Shifts δA = 279 Hz / 100 MHz = 2.79 ppm δM = 149 Hz / 100 MHz = 1.49 ppm δX = 39 Hz / 100 MHz = 0.39 ppm Coupling constants JAM = 4.5 Hz; JAX = 7.5 Hz; JMX = 11.0 Hz; 1st Order Analysis ΔνAX = νA - νX = 279 - 39 = 240 Hz ΔνAM = νA - νM = 279 - 149 = 130 Hz ΔνMX = νM - νX = 149 - 39 = 110 Hz ΔνAX / JAX = 240 / 7.5 = 32.0 ΔνAM / JAM = 130 / 4.5 = 28.9 ΔνMX / JMX = 110 / 11 = 10.0 All ratios are significantly greater than so a 1st order analysis is justified All ratios are significantly greater than so a 1st order analysis is justified December 2007 34 Please Keep Absolutely Confidential Problem 325 Spin System Chemical Shifts Copyright: Copying or duplicating these solutions in any form is strictly prohibited ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman AMX2 Problem 326 Spin System δA = 302 Hz / 100 MHz = 3.02 ppm δM = 160 Hz / 100 MHz = 1.60 ppm δX = 37 Hz / 100 MHz = 0.37 ppm Coupling constants JAM = 12.0 Hz; JAX = 5.0 Hz; JMX = 8.0 Hz; 1st Order Analysis ΔνAX = νA - νX = 302 - 37 = 265 Hz ΔνAM = νA - νM = 302 - 160 = 142 Hz ΔνMX = νM - νX = 160 - 37 = 123 Hz ΔνAX / JAX = 265 / 5.0 = 53.0 ΔνAM / JAM = 142 / 12.0 = 11.8 ΔνMX / JMX = 123 / 8.0 = 15.4 A2M2X Chemical Shifts δA = 1000 Hz / 200 MHz = 5.0 ppm δM = 500 Hz / 200 MHz = 2.5 ppm δX = 100 Hz / 200 MHz = 0.5 ppm Coupling constants JAM = 3.0 Hz; JAX = 7.0 Hz; JMX = 10.0 Hz; 1st Order Analysis ΔνAX = νA - νX = 1000 - 100 = 900 Hz ΔνAM = νA - νM = 1000 - 500 = 500 Hz ΔνMX = νM - νX = 500 - 100 = 400 Hz ΔνAX / JAX = 900 / 7.0 = 128.6 ΔνAM / JAM = 500 / 3.0 = 166.7 ΔνMX / JMX = 400 / 10.0 = 40.0 All ratios are significantly greater than so a 1st order analysis is justified All ratios are significantly greater than so a 1st order analysis is justified December 2007 35 Please Keep Absolutely Confidential Problem 327 Spin System ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman AMX3 Chemical Shifts δA = 710 Hz / 100 MHz = 7.10 ppm δM = 585 Hz / 100 MHz = 5.85 ppm δX = 192 Hz / 100 MHz = 1.92 ppm Coupling constants JAM = 15.3 Hz; JAX = 6.9 Hz; JMX = 1.6 Hz; 1st Order Analysis ΔνAX = νA - νX = 710 - 192 = 518 Hz ΔνAM = νA - νM = 710 - 585 = 125 Hz ΔνMX = νM - νX = 585 - 192 = 393 Hz ΔνAX / JAX = 518 / 6.9 = 84.7 ΔνAM / JAM = 125 / 15.3 = 8.2 ΔνMX / JMX = 393 / 1.6 = 245.6 All ratios are significantly greater than so a 1st order analysis is justified JAM = 15.3 Hz is typical of a coupling between vinylic protons which are trans to each other (see Section 5.7) December 2007 36 Copyright: Copying or duplicating these solutions in any form is strictly prohibited Please Keep Absolutely Confidential Problem 328 Spin System Copyright: Copying or duplicating these solutions in any form is strictly prohibited ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman ADMX3 1st Order Analysis ΔνAD = νA ΔνAM = νA ΔνAX = νA ΔνDM = νD ΔνDX = νD ΔνMX = νM- νD = 956 - 695 = 261 Hz νM = 956 - 619 = 337 Hz νX = 956 - 205 = 751 Hz νM = 695 - 619 = 76 Hz νX = 695 - 205 = 490 Hz νX = 619 - 205 = 414 Hz ΔνAD / JAD = 261 / 261 ΔνAM / JAM = 337 / 8.2 = 41.1 ΔνAX / JAX = 751 / 751 ΔνDM / JDM = 76 / 15.8 = 4.8 ΔνDX / JDX = 490 / 6.9 = 71.0 ΔνMX / JMX = 414 / 1.6 = 258.8 All ratios are significantly greater than so a 1st order analysis is justified The critical coupling constant is JDM = 15.8 Hz which is typical of a coupling between vinylic protons which are trans to each other (see Section 5.7) The compound is: O H Chemical Shifts Coupling constants December 2007 δA = 956 Hz / 100 MHz = 9.56 ppm; δD = 695 Hz / 100 MHz = 6.95 ppm; δM = 619 Hz / 100 MHz = 6.19 ppm; δX = 205 Hz / 100 MHz = 2.05 ppm; M 37 H C H JAD= < Hz; JAM = 8.2 Hz; JAX = < Hz; JDM = 15.8 Hz; JDX = 6.9 Hz; JMX = 1.6Hz; D C A C CH3 X Please Keep Absolutely Confidential Problem 329 ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman Spin System AMX3 Chemical Shifts Problem 330 Copyright: Copying or duplicating these solutions in any form is strictly prohibited Spin System A2X δA = 80 Hz / 60 MHz = 1.33 ppm δM = 220 Hz / 60 MHz = 3.67 ppm δX = 320 Hz / 60 MHz = 5.33 ppm Of the isomeric anilines, only compounds and have the correct symmetry to give a spectrum with only two chemical shifts in the aromatic region, in the ratio 2:1 Both and would give A2X spin systems The measured coupling constant is 7.7 Hz which is in the range for protons which are ortho to each other Compound is the correct answer December 2007 38 NH2 Br Br HA HA HX Please Keep Absolutely Confidential Copyright: Copying or duplicating these solutions in any form is strictly prohibited ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman Problem 331 Problem 332 All of the protons in the 1H spectrum 1,5-dichoronaphthalene have protons which are ortho to them This means that every proton must have at least one large (>7 Hz) ortho coupling The spectrum has one proton (at δ 7.1) which has only a small coupling so this cannot be the spectrum of 1,5-dichloronaphthalene The spectrum is obtained after D2O exchange so the carboxylic acid and phenolic protons will not be present and the spectrum only contains the aromatic and vinylic protons The spectrum shows distinct resonances therefore compounds and can be eliminated because they would each have only resonances (on symmetry grounds) The spectrum is an AMX spectrum with couplings between A and X of about 8.3 Hz (typical of an ortho coupling) and coupling between M and X of about 2.7 Hz (typical of a meta coupling) Two possible structure are given below The proton at about δ 7.1 shows no large coupling (> Hz), this means that it has no protons ortho to it This eliminates compounds and since all protons in these compounds will have at least one large ortho coupling Compounds and differ by the stereochemistry at the double bond The proton at δ 6.4 is clearly one of the vinylic protons and it is coupled to the other vinylic proton at δ 7.6 The coupling constant is 16 Hz and this characteristic of vinylic protons which are trans to each other The correct answer is compound OH COOH HM HM Cl HX HA HA Cl HX HX Cl HA 2,7-dichloronaphthalene December 2007 39 HM Cl HX HM HA 2,6-dichloronaphthalene ... Absolutely Confidential ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman Copyright: Copying or duplicating these solutions in any form is strictly prohibited BrCH2... Confidential 17 Br ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman 21 Br Copyright: Copying or duplicating these solutions in any form is strictly prohibited... Absolutely Confidential ORGANIC STRUCTURES FROM SPECTRA – 4th EDITION L D Field, S Sternhell and J R Kalman O 33 O O 34 37 O 41 N CH3 O C O 45 C O CH3 O CH3 H CH3 O O H t-butyl acetoacetate dibenzylamine