General comments
• inspect molecular formula CmHh0oNnXx: Degree of unsaturation m + 1 — 0.5(h + x — n)
• identify signals of CH3 and exchangeable protons in ID 1H sectrum
• arbitrary numbering (e.g., from lower to higher value of chemical shift) of resolved resonances in all spectra
• identification of the individual spin systems using DQF-COSY
• resolve geminal protons using HSQC
• connect molecular fragments/isolated spins using HMBC, NOESY
specify the stereochemistry (relative configuration) by means of j— and NOE interaction
Jan Novotný
Task 1:
Unknown substance C10H20O
Jan Novotný
Task 1:
ID *H of Ci0H20O
4.0
—1—
3.5
3.0
—1—
2.5
fl (ppm)
—1—
2.0
—1—
1.5
—1—
1.0
—r
0.5
Jan Novotný
3/5
Task 1: ./-connectivity of C10H20O
• methyls la,2d connected to CH 51
• remaining crosspeak of CH 51 to CH 9g
O  methyls la,2d
diastereotopic =>* chiral carbon 9
I
a. .    1  H  2_. .d
H3C
5 9
g
H
CH
I 2H
4^
UnHg-Hm
3 2 C02-1H (ppm)
if >
Jan Novotný
4/5
Task 1: ./-connectivity of C10H20O
• CH 9g has crosspeaks with deshielded 10m OH group (n)
• CH 9g has two crosspeaks with diastereotopic protons 4if
H   fH H
f I
E
S 2
4^
UnHg-Hm"
UnHm-Hn
3 2 C02-1H (ppm)
if >
Jan Novotný
4/5
Task 1: ./-connectivity of C10H20O
• CH 10m connected with CH2 8ck
• CH2 4if connected with CH2 7bj
I 2H
3J
4^
UnHm-Hn
3 2 C02-1H (ppm)
Jan Novotný
4/5
Task 1: J-connectivity of C10H20O
• CH2 8ck weakly coupled with CH2 7bj closing ring
• protons b and k coupled to CH 6h which is connected to methyl 3e
• other expected crosspeaks in DQ-COSY
crowded / overla pped, found topology confirmed
in HMBC (3/aJhc)
a,     1 H 2^>, ,d
b M
1-
E
ä 2
UnHc-J
UnHg-Hm"
DnHk-Hm"
UnHm-Hn
DnHJ -H j
3 2 (ö2- 1H (ppm)
Jan Novotný
Task 1: J-con necti vity of C10H20O
• CH2 8ck weakly coupled with CH2 7bj closing ring
• protons b and k coupled to CH 6h which is connected to methyl 3e
• other expected crosspeaks in DQ-COSY
crowded/overlapped, found topology confirmed
in HMBC (3/4Jhc)
3~J3 MENTHOL
Jan Novotný
30
35-
E
Q_ Q.
Ü
CO
40-
45
50
HSQC HMBC
UnC6-Hh
UnC6-He
UnC6-Hi UnC6-Hk
UnC6-Hb
30
UnC7-He^ UnC6-Hf
UnC7-Hk*
UnC7-Hj \ UnC7"
35
Hb
UnC7-Hi
40
UnC8-He
UnC8-Hm  UnC8_Hk    „_ „\ UnC8-Hb UnC8-Hn \ xUnC8-Hh \ /
45
UnC9-Hn UnC9-Hm     UnC9-Hl UnC9_Hd
UnC9-Hg
UnC8-Hc UnC9-Ha
50
4 2 G)2- 1H (ppm)
=
4/5
Task 1:
Stereochemistry of menthol CiqH2oO
• lo2:
homonuclear/heteronuclear couplings
• large couplings preserved in ID slices of HSQC:
axial H - 2 visible interactions (geminal and vicinal) x equatorial H - only geminal
• ID TOCSY: selective decoupling =4> simplification of complex multiplets
• DQF-COSY: analysis of phase sensitive spectrum
• lo3: NOE contacts (axial strong)
He
3JXA = small 3JXB = large
c
3JHC — 6-8 Hz 2JHr = 5-7 Hz
H
B
3JXA = small 3JXB = small
3JHC = 1-3 Hz R
2JHr = 0-2 Hz
□ 31
Task 1:
Stereochemistry of menthol CiqH2oO
• lo2:
homonuclear/heteronuclear couplings
• large couplings preserved in ID slices of HSQC:
axial H - 2 visible interactions (geminal and vicinal) x equatorial H - only geminal
• ID TOCSY: selective decoupling =4> simplification of complex multiplets
• DQF-COSY: analysis of phase sensitive spectrum
• lo3: NOE contacts (axial strong)
h9
Task 1:
Unknown substance C21H26O7
Jan Novotný