Problem O, C5H10O2 DBE = {[(2x5)+2]-10}/2 = 1

Problem O, C5H10O2 DBE = {[(2x5)+2]-10}/2 = 1
2 ‘O’ and IR peak at 1740 suggests: ester = 1DBE

Integration ratios: 2 : 3 : 2 : 3 =10
C5H10O2 Integration ratios: : : 2 : 3 =10 d 4 - what can shift a CH2 down to 4? only –O- p. 123

so it is next to another CH2
: : 2 : 3 C5H10O2 but this is a triplet so it is next to another CH2 but this is a sextet p. 123

2 : 3 : 2 : 3 C5H10O2 but this is a sextet
: : 2 : 3 C5H10O2 but this is a sextet so it is next to 6-1 = 5 H’s only one peak left a – CH3 !! p. 123

always check to see shifts are reasonable
: : 2 : 3 C5H10O2 could have started here always check to see shifts are reasonable p. 123

Problem P C6H12O DBE = {[(2x6)+2]-12}/2 = 1
1 ‘O’ and IR peak at 1720 suggests: >C=O NO 2750 peak, so probably ketone what sort of carbonyl? how do we verify this – look in 1H NMR for –CHO at d 10

d 1 = -CH3 – a triplet so next to a –CH2- , so we have a –CH2CH3
Problem P C6H12O no d 10, so must be a ketone. start here Integrations: 2:3:2:2:3 = 12 d 1 = -CH3 – a triplet so next to a –CH2- , so we have a –CH2CH3 we now have to decide is this the triplet , quintet or the sextet, which are all –CH2- ????

try different approach – only functional group is ketone
Problem P C6H12O ?-CH2CH3 Integrations: 2:3: 2:2:3 = 12 try different approach – only functional group is ketone -CHx-CO-CHY- H’s next to a ketone are in 2-3 region so we have a –CH2- and a –CH3 so we now know we have CH3-CO-CH2-

so we now know we have CH3-CO-CH2-
p. 124 Problem P C6H12O ?-CH2CH3 Integrations: 2:3:2:2:3 = 12 so we now know we have CH3-CO-CH2- triplet, so next to –CH2- but don’t forget we have already found a –CH2-CH3 CH3-CO-CH2-CH2- so now we have found all six carbons!!

CH3-CO-CH2-CH2-CH2-CH3 now check splittings, and d
Problem P C6H12O Integrations: 2:3:2:2:3 = 12 CH3-CO-CH2-CH2- -CH2-CH3 so they must be joined! CH3-CO-CH2-CH2-CH2-CH3 now check splittings, and d s t t <= expect d <= expect between 2 and 1.3

Problem Q C5H10O2 DBE = {[(2x5)+2]-10}/2 = 1
2 ‘O’ and IR peak at 1740 suggests: ester = 1DBE

most downfield peak will be on –O- so
Problem Q C5H10O2 Integrations: : : 2 : 3 = 10H ester most downfield peak will be on –O- so CH2 next to a carbonyl is 2-3, so

<= triplet, so next to –CH2-
Problem Q C5H10O2 Integrations: : : 2 : 3 = 10H <= triplet, so next to –CH2- <= sextet, so next to 5H 2 + 3

p. 125 Problem Q C5H10O2 Integrations: : : 2 : 3 = 10H check data

Problem R C5H12O DBE = {[(2x5)+2]-12}/2 = 0 1 ‘O’ but no –OH or C=O
so ether – there is an 1100 C-O str

so most downfield H’s next to O
p. 126 Problem R C5H12O Integrations 2:3 : 2:2:3 = 12H ether = C-O-C so most downfield H’s next to O CH3-O = singlet CH2 is triplet so next to CH2 so CH3OCH2CH2- most likely this is the next peak but to be sure, we can now go to the end

CH3 triplet so next to -CH2-
Problem R C5H12O Integrations 2:3 : 2:2:3 = 12H so CH3OCH2CH2- CH3 triplet so next to -CH2- = -CH2CH3 but we have now found all 5 carbon atoms so CH3OCH2CH2-CH2CH3 s t t <=check !!!

Problem S C8H9BrO DBE = {[(2x8)+2]-(9+1)}/2 = 4
> 6C, d 7 so benzene para (maybe) functional group = -OH

-OH, -Br, benzene (para, maybe) confirmed
Problem S C8H9BrO Integrations: 2: : : : = 9 -OH, -Br, benzene (para, maybe) confirmed para-benzene = C6H4 so C8H8-C6H4 left to find = C2H4 d d OH do not couple

we have a CH (q next to 3) and a CH3 (d next to 1)
p. 127 Problem S C8H9BrO Integrations: 2: : : : = 9 para-benzene = C6H4 so C8H8-C6H4 left to find = C2H4 -OH, -Br, we have a CH (q next to 3) and a CH3 (d next to 1) so >CHCH3

Problem S C8H9BrO Integrations: 2: : : : = 9 -CHCH3 -OH, -Br,

Problem S C8H9BrO normal d ~7.3 shielded d 6.8 as well, Ar-OH d 5-10
and Ar-OH has IR 1220 not at around 1100 correct

Problem T C11H12 >6C, d 7 so benzene DBE = {[(2x11)+2]-(12)}/2 = 6
two bands, so MONO 2200 = ? = 6 DBE

Problem T C11H12 Integrations 5 : 2 : 2 : 3 = 12 these are all coupled
so not singlet

CH3 is a triplet, so is next to a CH2, which is a sextet
Problem T C11H12 Integrations : : 2 : 3 = 12 start where we know! CH3 is a triplet, so is next to a CH2, which is a sextet so must have 5 neighbors, 3 of which are CH3, so other 2 must be –CH2

Problem T C11H12 Integrations 5 : 2 : 2 : 3 = 12 CH2---CH2---CH3 t 6 t

Problem U C8H10ClN ? DBE = {[(2x8)+2+1]-(10+1)}/2 = 4
> 6 C, d 7 so benzene so use NMR Functional group -NH2

Note the ‘leaning’ shape
Problem U C8H10ClN Note the ‘leaning’ shape Integrations: 2: : = 10 -Cl, -NH2 para-benzene = C6H4 should be singlet, no coupling we still need to find C8H10ClN – C6H6ClN = C2H4 -CH2-CH2-

always then join bifunctional or higher groups together
Problem U C8H10ClN Integrations: 2: : = 10 -Cl, -NH2 -CH2-CH2- always then join bifunctional or higher groups together

Problem U C8H10ClN Integrations: 2:2 2:2 2 = 10 -Cl, -NH2
now, 2 choices

Problem U C8H10ClN Integrations: 2:2 2:2 2 = 10 at least d 3.5 d 7-7.3
shielded to 6.8 correct

-CN Nitrile and benzene account for all DBE
p. 130 Problem V C9H9N ? DBE = {[(2x9)+2+1]-(9)}/2 = 6 > 6C, d 7 so benzene maybe mono? Functional Group? -CN Nitrile and benzene account for all DBE

Problem V C9H9N =9H Integrations: 5 : 1 : 3 = 9 + mono-subs-benzene
C9H9N – (C6H5 + CN) = C2H4 so >CHCH3 q d

p. 130 Problem V C9H9N =9H Integrations: : : = 9 >CHCH3

Problem W C10H12O DBE = {[(2x10)+2]-12)}/2 = 5 >6 C, d 7 so benzene
probably mono-subs Functional Group ? ketone – confirm in NMR with no d 10 What sort of ketone? >1700, satd, so? 8

satd ketone, not next to benzene ring
p. 131 Problem W C10H12O Integrations: : : : = 12 X satd ketone, not next to benzene ring CH3 triplet so next to CH2 –which?

Problem W C10H12O Integrations: 5 : 2 : 2 : 3 = 12 -CH2CH3
next to anything else? C C CC = C11 !!! d = 2-3, so on carbonyl

p. 131 Problem W C10H12O Integrations: : : : = 12 d?

Problem X C9H10O ? DBE = {[(2x9)+2]-10)}/2 = 5
> 6 C, d 7 so benzene Functional group ? >C=O 2750, so –CHO confirm in NMR

confirms para-benzene ring d 10 confirms CHO C6H4
Problem X C9H10O : : : : = 10 confirms para-benzene ring d 10 confirms CHO C6H4 Have found C7H5O, so C2H5 left to find -CH2-CH3 q t

p. 132 Problem X C9H10O : : : : = 10 -CH2-CH3 OHC- d 7.8

Problem Y C10H12O2 DBE = {[(2x10)+2]-12)}/2 = 5
> 6 C, d 7 so benzene mono subst Functional group = ester can we tell what type of ester??? 1740, so saturated both sides!!!

Problem Y C10H12O2 Integrations 5 : 3 : 2:2 = 12H
} C7H5O2 so C3H7 left to find satd CH3 CH2 CH2 d 3.5 so on O coupled

p. 133 Problem Y C10H12O2 Integrations : : 2:2 = 12H

Problem Z C11H14O2 DBE = {[(2x11)+2]-14)}/2 = 5
> 6 C, d 7 so benzene ?-subst Functional group = acid type of acid??? <1700, so conjugated (to what) benzene ring

-COOH is at d 10-16 not shown in above spectrum
Problem Z C11H14O2 Integrations 2: : = 13 -COOH is at d not shown in above spectrum Benzene is para conjugated C4H9 C7H5O2

Problem Z C11H14O2 Integrations 2:2 : 9 = 13 (CH3)3 identical C4H9
-C(CH3)3 9H ~ d 1

Problem O, C5H10O2 DBE = {[(2x5)+2]-10}/2 = 1

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Problem O, C5H10O2 DBE = {[(2x5)+2]-10}/2 = 1

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Presentation on theme: "Problem O, C5H10O2 DBE = {[(2x5)+2]-10}/2 = 1"— Presentation transcript:

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