Table Of Content1 General introduction 1
1 Introduction
The phenomenon of nuclear magnetic resonance (NMR) is based on magnetic properties of nuclei and
therefore they are included here.
1.1 Magnetic properties of nuclei
All nuclei carry a charge and in some nuclei this charge spins on the nuclear axis generating a magnetic
field along the axis. These nuclei behave as tiny bar magnets. The magnetic properties of a nucleus can be
specified in terms of the nuclear spin quantum number I (I = 0, 1/2, 1, 3/2, 2, 5/2, ....., 7) and the magnetic
moment µ of the nucleus. The magnetic moment of the nucleus is proportional to the nuclear angular
momentum (nuclear spin) and is expressed by:
µ = γ p , (1)
with
|p| = [I(I + 1)]½ ħ . (2)
where ħ = h/(2π) and γ is a proportionality constant known as gyromagnetic or magnetogyric ratio
(differing for each nucleus and essentially measures the strength of nuclear magnets). h is Planck’s
constant (h = 6.626075.10−34 J s).
The magnetic moment µ can be also expressed in terms of the nuclear magneton µ by:
N
µ = gN µN p , (3)
where gN is known as the nuclear g-factor (which is determined experimentally). µN is defined as
µN = e ħ/(2 mP) = 5.0507866⋅10−27 J T−1 (e = electronic charge, mP = mass of the proton).
Each proton and neutron has its own spin and spin number. I is the resultant of these spins. If the sum
of protons and neutrons (i.e. mass number) is odd, I is half-integer (I = 1/2, 3/2, 5/2, ...), if both protons
and neutrons are even-numbered, I is zero (I = 0 denotes no spin) and if the sum is even, I is integer (I =
1, 2, 3, 4 ...). The magnetic properties of some NMR nuclei are summarized in Table 1. Nuclei with I > 0
may be called magnetic as they develop the magnetic fields along the axis of spins and give rise to the
phenomenon of nuclear magnetic resonance. Such nuclei do not simply possess magnetic dipoles, but
rather possess electric quadrupoles (it measures the electric charge distribution within a nucleus when it
possesses non−spherical symmetry) and interact with both, magnetic and electric gradients. The relative
importance of the two effects is related to their magnetic moments and electric quadrupole moments.
Landolt-Börnstein
New Series III/35D4
2 1 General introduction
Table 1. Magnetic properties of NMR nuclei.
Isotope Natural Spin quantum Magnetogyric Magnetic Quadrupole
abundance number ratio moment moment
% I γ [107 T-1 s-1] µ/µ Q [fm2]
N
1n 1/2 –1.913042
1H1 99.9844 1/2 26.752 2.7928474
2H1 0.156 1 4.107 0.85738 0.2860
3H1 – 1/2 28.5335 2.9788
3He 0.000137 1/2 –2.127624
2
7Li 92.5 3/2 3.256424 4.01
3
10B5 18.83 3 2.8747 1.8006 8.459
11B5 81.17 3/2 8.5827 2.6880 4.059
13C6 1.108 1/2 6.728 0.70216
14N7 99.635 1 1.9324 0.40357 2.02
15N7 0.365 1/2 –2.7126 –0.28304
17O8 0.037 5/2 –3.628 –1.8930 –2.558
19F9 100.00 1/2 25.179 2.6273
23Na 100 3/2 2.217520 10.89
11
29Si14 4.70 1/2 –5.319 –0.55477
31P15 100.00 1/2 10.840 1.1305
33S16 0.74 3/2 2.054 0.64274 –6.78
35Cl17 75.40 3/2 2.627 0.82089 –8.165
37Cl17 24.60 3/2 2.184 0.68329 –6.435
51V 99.750 7/2 5.1487 –5.2
23
57Fe 2.1 1/2 0.090623
26
59Co 100 7/2 4.627 40.4
27
73Ge 7.73 9/2 –0.8794677 –6.73
32
75As 100 3/2 1.43947 31.4
33
77Se 7.58 1/2 5.101 0.535042
34
79Br35 50.54 3/2 6.7256 2.0991 29.3
81Br35 49.46 3/2 7.2245 2.2626 27.0
89Y 100 1/2 –0.137415
39
95Mo 15.92 5/2 –0.9142 2.2
42
113Cd 12.22 1/2 –0.62230
48
117Sn 7.61 1/2 –9.589 –1.00104
50
119Sn50 8.58 1/2 –10.0318 –1.04728
123Te 0.908 1/2 –0.7369478
52
125Te 7.139 1/2 –0.8885051 –0.79
52
127I 100.00 5/2 5.33521 2.7937 –0.789
53
183W 14.40 1/2 – 0.11778
74
207Pb 22.6 1/2 5.56264 0.58219
82
Landolt-Börnstein
New Series III/35D4
1 General introduction 3
1.2 Spinning nuclei in magnetic fields
A spinning nucleus generates a magnetic moment and when placed in an uniform magnetic field with the
magnetic flux density B it tends to align itself with the field. Unless the axis of the nuclear magneton is
oriented exactly parallel or antiparallel to the magnetic field, a certain force is exerted by the applied
field. Because the nucleus is spinning, the effect is that its rotational axis draws out a circle perpendicular
to the external field (Fig. 1). This motion is called precession. The precessional angular velocity of a
spinning top is known as Larmor frequency ω which is proportional to the applied magnetic flux density
B of the magnetic field and can be expressed by:
ω = γ |B|. (4)
With ω /(2π) = ν and therefore 2 π ν = γ |B| the precessional frequency ν can be expressed by:
ν = γ |B| / (2 π). (5)
The Larmor frequency is such that a projection of the angular momentum on the direction of B always
assumes whole multiple of ħ and therefore, not all possible precession “cones” occur, only some selected
ones. The number of the possible alignments is 2I+1 for spin I in the direction of magnetic field. These
2I+1 orientations are quantized in the direction of magnetic field and the absorbable component m of the
I
spin I can be expressed by the following equations for half-integer and integer spins, respectively:
m = I, I−1, I−2, ..., 1/2, −1/2, ..., −(I−2), −(I−1), −I, (6)
I
m = I, I−1, I−2, ..., 1, 0, −1, ..., −(I−2), −(I−1), −I. (7)
I
In each case there are 2I+1 values of the magnetic quantum number m. Each orientation is associated
I
with a different energy level E and can be expressed by:
E = − µ B or E = – γ ħ |B| m = – ħ ω m (8).
I I
This type of splitting of energy levels in magnetic fields for a nucleus (I > 0) is called nuclear Zeeman
splitting.
B
ω
Precessional orbit
Axis of rotation
Radio frequency ν
Fig. 1: Spinning nuclei in magnetic fields
Spinning nucleus
1.3 Theory of nuclear resonance
The basis of nuclear magnetic resonance is to induce transitions between the nuclear Zeeman energy
levels. Such transitions are affected by placing an alternating field Ha perpendicular to the applied field H
in such a way that frequency can be altered conveniently. Selection rules permit such transitions between
energy levels 2 and 1 that mI,2 − mI,1 = ∆mI = ± 1 i.e. ∆mI = +1 when energy is absorbed (transition is from
lower to higher energy level) and ∆m = −1 when energy is emitted (transition from higher to lower
I
energy level). The transitions from E2 to E1 energy levels can be expressed by:
∆E = E2 – E1 = γ h |B| mI,2 – γ h |B| mI,1 = γ h |B| (mI,2 – mI,1) (9)
Landolt-Börnstein
New Series III/35D4
4 1 General introduction
According to selection rules of quantum mechanics, m – m = ±1 depending on whether energy is
I,2 I,1
absorbed or emitted, Eq. (9) is reduced:
∆E = ± γ h |B| (10)
When the frequency of electromagnetic radiation necessary to induce a transition from one nuclear spin
state to another is exactly equal to the precessional frequency of spinning nucleus, they are in resonance
and the phenomenon of resonance occurs. Thus nuclear resonance (absorption or emission of energy)
occurs when a magnetic nucleus (I > 0) is placed in an uniform magnetic field H and subjected to
electromagnetic radiation of appropriate frequency matching to the precessional frequency of spinning.
Under these conditions the frequency of electromagnetic radiation causing resonance can be expressed
by:
∆E = h ν = γ h |B| or ν = γ |B| / (2 π). (11)
Eq. (11) also exhibits that the precessional frequency ν is γ |B| / (2 π).
Eq. (11) correlating electromagnetic frequency causing nuclear resonance with magnetic field strength
is the basis of NMR spectroscopy and from this equation the electro-radiation frequency causing the
resonance for various field strengths can be calculated. Precessional frequencies for some nuclei at
various magnetic field strengths are summarized in Table 2.
1.4 Chemical shift
The fundamental NMR Equation (11), ν = γ |B| / (2 π), exhibits that a single peak should be obtained from
the interaction of radiofrequency energy and the magnetic field on a nucleus as γ is characteristic for a
nucleus. However, the nucleus is shielded by an electron cloud whose density varies with the
environment. This variation gives rise to different absorption positions. Under the influence of the applied
magnetic field electrons circulate and generate their own magnetic field opposing the applied field and
cause a shielding effect. The magnitude of the induced field is proportional to the magnetic field. The
effective magnetic field B experienced by the nucleus is changed by this small local field σB (due to
eff
electronic circulation), such that B = B – σB with σ = shielding constant. This shielding effect influences
eff
the resonance condition:
ν = [γ |B| / (2 π)](1 – σ) (12)
A nucleus in different environments is shielded by the circulation of surrounding electrons to different
extents. Different values of σB, each depending on the magnitude of the applied B field are obtained for
the nucleus. Because the strength of the applied magnetic field cannot be determined to the required
degree of accuracy, the absolute position of absorptions cannot be obtained directly from the instrument.
However, the relative position of absorption can readily be obtained with an accuracy of ± 1 Hz or lower.
The separation of resonance frequencies of a nucleus in different structural environments from an
arbitrarily chosen standard is termed as chemical shift. A plot of the chemical shifts (frequencies of
absorption peaks) versus the intensities of absorption peaks (which for some nuclei may by integration
provide the number of nuclei) constitutes a NMR spectrum. The chemical shift is symbolized by δ (delta)
and is measured in ppm (parts per million) according to:
δ (in ppm) = [(ν – ν)/ ν] ⋅ 106 (13)
s r r
where νs and νr are the resonance frequencies in Hz of the sample s and the reference substance r,
respectively, at constant field B = Br = Bs. Since field and frequency are linearly related, Equation (13) can
be transformed to:
δ (in ppm) = [(B – B)/ B] ⋅ 106 (14)
s r r
Landolt-Börnstein
New Series III/35D4
1 General introduction 5
Table 2. Precessional frequencies ν as a function of the magnetic flux density B
ν [MHz]
B [T] 2.35 4.70 7.05 9.40 11.74 14.09 21.14
Nucleus
1H 100.0 200.0 300.0 400.0 500.0 600.0 900.0
1
2H 15.3 30.7 46.1 61.4 76.8 92.1 138.2
1
3H 106.7 213.3 320.0 426.7 533.3 640.0 960.0
1
3He 76.2 152.4 228.5 304.7 380.9 457.1 685.6
2
7Li 38.9 77.7 116.6 155.5 194.3 233.2 349.8
3
10B 10.5 21.5 32.2 43.0 53.7 64.5 96.7
5
11B 32.0 64.2 96.3 128.3 160.4 192.5 288.8
5
13C 25.1 50.3 75.4 100.6 125.7 150.9 226.3
6
14N 7.2 14.4 21.7 28.9 36.1 43.3 65.0
7
15N 10.1 20.3 30.4 40.5 50.7 60.8 91.2
7
17O 13.6 27.1 40.7 54.2 67.8 81.3 122.0
8
19F 94.1 188.2 282.2 376.3 470.4 564.5 846.7
9
23Na 26.5 52.9 79.4 105.8 132.3 158.7 238.1
11
29Si 19.5 39.7 59.6 79.5 99.3 119.2 17.8
14
31P 40.5 81.0 121.4 161.9 202.4 242.9 364.3
15
33S 7.6 15.3 23.0 30.7 38. 4.6 6.9
16
35Cl 9.6 19.6 29.4 39.2 49.0 58.8 88.2
17
37Cl 8.2 16.3 24.5 32.6 40.8 48.9 73.4
17
51V 9.6 52.6 78.9 105.2 131.4 157.7 236.6
23
57Fe 3.2 6.5 9.7 12.9 16.2 19.4 29.1
26
59Co 23.6 47.2 70.8 94.5 118.1 141.7 212.5
27
73Ge 3.5 7.0 10.5 14.0 17.4 20.9 31.4
32
75As 17.1 34.3 51.4 68.5 85.6 102.8 154.1
33
77Se 19.1 38.1 57.2 76.3 95.3 114.4 171.6
34
79Br 24.5 50.1 75.2 100.2 125.3 150.3 225.5
35
81Br 26.5 54.0 81.0 108.0 135.0 162.0 243.1
35
89Y 4.9 9.8 14.7 19.6 24.5 29.4 44.1
39
95Mo 6.5 13.0 19.5 26.1 32.6 39.1 58.6
42
113Cd 22.2 44.4 66.5 88.7 110.9 133.1 119.6
48
117Sn 35.6 71.3 106.9 142.5 178.1 213.8 320.6
50
119Sn 37.3 74.5 111.8 149.1 186.4 223.6 335.5
50
123Te 26.2 52.4 78.6 104.8 131.0 157.2 235.9
52
125Te 31.6 63.2 94.8 126.4 158.0 189.6 284.4
52
127I 20.0 40.0 60.0 80.0 100.0 120.0 180.1
53
129Xe 27.7 55.3 83.0 110.6 138.3 166.0 248.9
54
183W 4.1 8.3 12.5 16.6 20.8 25.0 37.4
74
187Os 2.3 4.6 6.9 9.2 11.5 13.8 20.7
76
195Pt 21.5 43.0 64.5 86.0 107.5 129.0 193.5
78
199Hg 17.8 35.7 53.5 71.3 89.1 107.0 160.4
80
205Tl 57.7 115.4 173.1 230.8 288.5 346.2 519.4
81
207Pb X 41.8 62.8 83.7 104.6 125.5 188.3
82
Landolt-Börnstein
New Series III/35D4
6 1 General introduction
where Bs and Br refer to the fields at resonance for the sample s and the reference substance r,
respectively, at constant frequency ν = νr = νs. The chemical shift in Hz is directly proportional to the
applied field B and therefore to the applied frequency. It is dependent on diamagnetic shielding induced
by the applied field. It is the ratio of the necessary change in field to the reference field or the necessary
change in frequency to the reference frequency and hence a dimensionless number. To spread out
chemical shifts i.e. to increase separation of resonance signals, a high magnetic field is applied which
constitutes high resolution NMR spectroscopy. In the 1950s and 1960s, chemical shifts were also
expressed in an alternative scale, τ, which is related to δ:
τ = 10.00 − δ (15)
but this convention has been abandoned.
High values of chemical shifts (δ in ppm) correspond to high-frequency shifts (“downfield”) due to a de-
shielding of the nucleus; and low values correspond to low-frequency shifts (“upfield”) due to shielding.
1.5 Coupling constant
The position of the resonance signal of a nucleus A depends on its electronic and magnetic environment.
In addition, it may be affected by neighboring nuclei B if these are magnetic themselves and act through
intervening bonds (scalar coupling). A nucleus B can either have its magnetic moment aligned parallel to
that of nucleus A or opposite; both spin orientations of B are nearly equally populated (Boltzmann distri-
bution). In this way, nucleus B can either increase the net magnetic field experienced by A or decrease it,
a consequence of the different energies of the spin interaction. Thereby, the two spin orientations of B
give rise to two resonance lines of nucleus A. Their distance, usually given in Hz, is called the coupling
constant J. If the antiparallel combination of the spin states of A and B is energetically favored (right-
hand resonance of the doublet), the sign of J is positive by definition, whereas J < 0 if the parallel combi-
nation is favored. Such signs cannot be read easily from NMR signals so that, generally, coupling con-
stants reported in the literature are given as absolute values. Of course, nucleus A has the same effect on
B, i.e., the signal of B is a doublet as well with the same frequency distance.
Coupling constants (in Hz) are independent of the external field because they reflect an intramolecular
nuclear interaction energy. However, there is a strong dependence of J-values of the number of bonds
between the coupling partners. One-bond couplings [1J(A,B)] are the largest, and J-values tend to de-
crease with the number of intervening bonds: geminal [2J(A,B)], vicinal [3J(A,B)] and long-range coup-
ling [nJ(A,B); n > 3]. On the other hand, electronegativies of attached atoms or groups and stereochemical
influences play a significant role as well.
If a nucleus A has more than one coupling partner, its signal appearance changes in that each partner
causes a new duplication. Thereby, multiplets arise from which the number of coupling partners and the
coupling constants for each pair can be determined. However, this evaluation procedure is possible only
in first-order spin systems where the ratio of the chemical shift difference ∆ν = ν (A) – ν (B) (in Hz, not in
ppm) and the coupling constant J(A,B)is larger than 10. At lower ratios, quantum mechanics effects may
obscure line distances and relative intensities within multiplets so that exact chemical shifts and coupling
constants can be detected only by calculation and simulation, not by direct evaluation.
1.6 Organization of Data
The volume III/35D contains chemical shifts δ (in ppm) and coupling constants J (in Hz) for carbon-13
nuclei. The present subvolume III/35D, Part 4 provides data for natural compounds. For each nucleus the
arrangement of compounds is based on their gross formulae arranged according to Hill's system: carbon
comes first, hydrogen second and then other elements in alphabetical order.
Landolt-Börnstein
New Series III/35D4
2.1 Introduction to Carbon-13 NMR of Natural Products 1
2.1 Introduction to Carbon-13 NMR of Natural Products
Direct observation of carbon atoms in carbon containing functional groups has been available on a
practical basis only since the early 1970s. The 12C nucleus is not magnetically active ( spin number I = 0),
but the 13C nucleus like 1H nucleus, has a spin number of ½. The natural abundance of 13C is only 1.1%
that of 12C, its sensitivity is about 1.6% that of 1H and overall sensitivity of 13C compared with 1H is about
1/5700. The low natural abundance of 13C (1.1%), relatively small gyromagnetic ratio and relatively long
spin-relaxation time present difficulties in recording a 13C-NMR spectrum by continuous-wave (CW)
technique. A good spectrum is obtained by the Fourier Transform NMR (FT-NMR). The chemical shifts
normally range between δ 0-200 ppm, and therefore, these represent the spread of chemical shifts of
about twenty times that of proton. Carbon-13 NMR has emerged as an analytical tool of enormous power.
It has been used to detect and study the structure of intermediates in organic reactions including
carbocations, free radicals, and carbanions. 13C NMR spectra for a vast variety of compounds from almost
all series have been extensively investigated.
This subvolume includes Carbon−13 NMR data of natural products. Chemical shifts δ (in ppm) and
coupling constants nJ(HX) (in Hz) have been organized by arranging the gross formulae according to
Hill's system as explained in the introduction (section 1.6). Chemical shifts (in ppm) are expressed
relative to the signal of tetramethylsilane (TMS) as an internal standard. The prefix n in nJ indicates the
number of bonds over which coupling is occuring.
Abbreviations
D O − Deuterium oxide C D − Benzene−d
2 6 6 6
C D N − Pyridine−d DMSO-d − Dimethyl sulfoxide-d
5 5 5 6 6
CD OD − Methanol−d CF COOD − Trifluoroacetic acid-d
3 4 3
n.a. – Not assigned n.d. – Not detected
n.m. – Not measured n.o. – Not observed due to solvent signal
n.r. – Not reported ax – Axial
eq. – Equatorial Ac – Acetyl (COCH )
3
Bz – Benzoyl Glc or G – Glucose
Nic – Nicotinoyl Rh – Rhamnose
iBu – Isobutyl Gem – Gemminal
Api – Apiosyl Xyl – Xylose
Ph(i) – Phenyl ipso Ph(o) – Phenyl ortho
Ph(m) – Phenyl meta Ph(p) – Phenyl para
Ar or Ph or φ – Phenyl Tigl – Tiglate
*,** – Assignment with same superscript may be interchanged
R, S – Denote configuration (R = Rectus; S = Sinister)
E, Z – Denote configuration (E = Entgegen; Z = Zusammen)
ff – Signal hidden in solvant or overlapped with solvent signal
Landolt-Börnstein
New Series III/35D4
Landolt-Börnstein III/35D4
Index of natural compounds investigated by C-13 NMR
Structure No. 16 -- C H NO Structure No. 36 -- C H NO
Structures with 4 carbon atoms 8 9 3 10 11 4
Structure No. 17 -- C H O Structure No. 37 -- C H O
8 12 3 10 12 4
Structure No. 1 -- C H O
4 6 3
Structure No. 18 -- C H O Structure No. 38 -- C H O
8 12 5 10 12 4
Structures with 5 carbon atoms Structure No. 19 -- C H NO Structure No. 39 -- C H O
8 13 10 12 4
Structure No. 2 -- C5H7N3 Structure No. 20 -- C8H13NO2 Structure No. 40 -- C10H13NO5
Structure No. 3 -- C5H10O4 Structure No. 21 -- C8H17NO3 Structure No. 41 -- C10H14O2
Structure No. 42 -- C H O
Structures with 6 carbon atoms Structures with 9 carbon atoms 10 14 2
Structure No. 43 -- C H O
10 14 3
Structure No. 4 -- C6H7NO Structure No. 22 -- C9H10N2O3
Structure No. 44 -- C H O
10 14 4
Structure No. 5 -- C6H8O3 Structure No. 23 -- C9H10O3
Structure No. 45 -- C H O
10 16
Structure No. 6 -- C6H8O3 Structure No. 24 -- C9H10O4
Structure No. 46 -- C H O
10 16 3
Structure No. 7 -- C6H10O3 Structure No. 25 -- C9H11NO3
Structure No. 47 -- C H O
10 16 3
Structure No. 8 -- C6H10O3 Structure No. 26 -- C9H11NO5
Structure No. 48 -- C H O
10 16 3
Structure No. 9 -- C6H11NO2S Structure No. 27 -- C9H12O4
Structure No. 49 -- C H O
10 16 5
Structure No. 10 -- C6H11NO3S Structure No. 28 -- C9H12O4
Structure No. 50 -- C H O
10 16 8
Structure No. 11 -- C6H14O2 Structure No. 29 -- C9H12O5
Structure No. 51 -- C H ClO
10 17 2
Structure No. 30 -- C H O
9 12 5
Structures with 7 carbon atoms Structure No. 52 -- C H O
10 18
Structure No. 31 -- C H O
9 14 2
Structure No. 12 -- C7H6N2O2 Structure No. 53 -- C10H18O2
Structure No. 32 -- C H O
9 16 4
Structure No. 54 -- C H O
10 18 3
Structures with 8 carbon atoms
Structures with 10 carbon atoms Structure No. 55 -- C H O
10 20 4
Structure No. 13 -- C H Cl O
8 8 2 2
Structure No. 33 -- C10H6O3 Structure No. 56 -- C10H21NO4
Structure No. 14 -- C H N O
8 8 2 3
Structure No. 34 -- C10H9NO3
Structure No. 15 -- C H O
8 8 4
Structure No. 35 -- C H NO
10 9 4
Structures with 11 carbon atoms Structure No. 83 -- C H O Structure No. 109 -- C H NO
11 18 5 12 15 4
Structure No. 57 -- C11H6O4 Structure No. 84 -- C11H18O6 Structure No. 110 -- C12H15NO4
Structure No. 58 -- C11H8O3 Structure No. 85 -- C11H18O6 Structure No. 111 -- C12H15NO7
Structure No. 59 -- C11H8O3 Structure No. 86 -- C11H18O8 Structure No. 112 -- C12H16O2
Structure No. 60 -- C11H8O3 Structure No. 87 -- C11H18O8 Structure No. 113 -- C12H16O4
Structure No. 61 -- C11H8O3 Structure No. 88 -- C11H18O9 Structure No. 114 -- C12H16O4
Structure No. 62 -- C11H10O3 Structure No. 89 -- C11H20O5 Structure No. 115 -- C12H16O4
Structure No. 63 -- C11H10O5 Structure No. 90 -- C11H20O9 Structure No. 116 -- C12H16O5
Structure No. 64 -- C11H10O5 Structures with 12 carbon atoms Structure No. 117 -- C12H16O5
Structure No. 65 -- C11H10O5 Structure No. 91 -- C H O Structure No. 118 -- C12H16O5
12 8 4
Structure No. 66 -- C11H11NO Structure No. 92 -- C H O Structure No. 119 -- C12H16O7
12 10
Structure No. 67 -- C11H12O3 Structure No. 93 -- C H O Structure No. 120 -- C12H16O7
12 10
Structure No. 68 -- C11H12O3 Structure No. 94 -- C H O Structure No. 121 -- C12H17NO6
12 10 3
Structure No. 69 -- C11H12O4 Structure No. 95 -- C H NO Structure No. 122 -- C12H18O2
12 11 5
Structure No. 70 -- C11H12O7 Structure No. 96 -- C H O Structure No. 123 -- C12H18O3
12 12 3
Structure No. 71 -- C11H13ClO3 Structure No. 97 -- C H O Structure No. 124 -- C12H18O4
12 12 3
Structure No. 72 -- C11H13NO3 Structure No. 98 -- C H O Structure No. 125 -- C12H18O4
12 12 3
Structure No. 73 -- C11H16O3 Structure No. 99 -- C H O Structure No. 126 -- C12H20O5
12 12 4
Structure No. 74 -- C11H16O3 Structure No. 100 -- C H O Structures with 13 carbon atoms
12 12 4
Structure No. 75 -- C H O
11 16 5 Structure No. 101 -- C H O Structure No. 127 -- C H O
12 12 4 13 8 4
Structure No. 76 -- C H O
11 16 6 Structure No. 102 -- C H NO Structure No. 128 -- C H O
12 13 3 13 8 4
Structure No. 77 -- C H O
11 16 6 Structure No. 103 -- C H NO Structure No. 129 -- C H O
12 13 3 13 8 5
Structure No. 78 -- C H O
11 16 10 Structure No. 104 -- C H O Structure No. 130 -- C H O
12 14 2 13 8 5
Structure No. 79 -- C H NO
11 17 7 Structure No. 105 -- C H O Structure No. 131 -- C H O
12 14 3 13 8 6
Structure No. 80 -- C H NO
11 17 8 Structure No. 106 -- C H O Structure No. 132 -- C H NO
12 14 4 13 9
Structure No. 81 -- C H O
11 18 5 Structure No. 107 -- C H O Structure No. 133 -- C H NO
12 14 5 13 9 3
Structure No. 82 -- C H O
11 18 5 Structure No. 108 -- C H O Structure No. 134 -- C H NO
12 14 5 13 9 3
Structure No. 135 -- C H O Structure No. 162 -- C H NO Structure No. 188 -- C H O
13 10 2 13 21 3 14 16 5
Structure No. 136 -- C H O Structure No. 163 -- C H N Structure No. 189 -- C H NO
13 10 4 14 8 2 14 17 2
Structure No. 137 -- C H O Structure No. 190 -- C H NO
13 10 5 Structures with 14 carbon atoms 14 17 7
Structure No. 138 -- C H O Structure No. 191 -- C H NO
13 10 8 14 17 7
Structure No. 164 -- C H N O
14 8 2 3
Structure No. 139 -- C H O Structure No. 192 -- C H NO
13 12 3 14 17 9
Structure No. 165 -- C H O
14 10 4
Structure No. 140 -- C H O Structure No. 193 -- C H NO
13 12 4 14 17 9
Structure No. 166 -- C H O
14 10 4
Structure No. 141 -- C H O Structure No. 194 -- C H N O
13 12 4 14 17 3 3
Structure No. 167 -- C H O
14 10 5
Structure No. 142 -- C H O Structure No. 195 -- C H O
13 12 4 14 18 3
Structure No. 168 -- C H O
14 10 5
Structure No. 143 -- C H NO Structure No. 196 -- C H O
13 13 3 14 18 4
Structure No. 169 -- C H O
14 10 5
Structure No. 144 -- C H NO Structure No. 197 -- C H O
13 13 5 14 18 7
Structure No. 170 -- C H O
14 10 5
Structure No. 145 -- C H O Structure No. 198 -- C H ClO
13 14 4 14 19 3
Structure No. 171 -- C H O
14 10 5
Structure No. 146 -- C H O Structure No. 199 -- C H NO
13 14 4 14 19 2
Structure No. 172 -- C H O
14 10 6
Structure No. 147 -- C H O Structure No. 200 -- C H NO
13 16 4 14 19 8
Structure No. 173 -- C H O
14 10 6
Structure No. 148 -- C H O Structure No. 201 -- C H O
13 16 4 14 20 2
Structure No. 174 -- C H O
14 10 7
Structure No. 149 -- C H O Structure No. 202 -- C H O
13 16 4 14 20 4
Structure No. 175 -- C H N O
14 12 2 3
Structure No. 150 -- C H O Structure No. 203 -- C H O
13 16 9 14 20 4
Structure No. 176 -- C H O
14 12 2
Structure No. 151 -- C H Cl O Structure No. 204 -- C H O
13 17 4 14 22 2
Structure No. 177 -- C H O
14 12 2
Structure No. 152 -- C H NO Structure No. 205 -- C H O
13 17 14 22 5
Structure No. 178 -- C H O
14 14
Structure No. 153 -- C H O Structure No. 206 -- C H O
13 18 2 14 22 8
Structure No. 179 -- C H O
14 14 2
Structure No. 154 -- C H O Structure No. 207 -- C H O
13 18 3 14 24 2
Structure No. 180 -- C H O
14 14 3
Structure No. 155 -- C H O Structure No. 208 -- C H O
13 18 5 14 24 3
Structure No. 181 -- C H O
14 14 3
Structure No. 156 -- C H NO Structure No. 209 -- C H O
13 19 2 14 26 9
Structure No. 182 -- C H O
14 14 4
Structure No. 157 -- C H O Structure No. 210 -- C H O
13 20 2 15 10 4
Structure No. 183 -- C H O
14 14 5
Structure No. 158 -- C H O
13 20 2 Structures with 15 carbon atoms
Structure No. 184 -- C H O
14 14 5
Structure No. 159 -- C H O
13 20 3
Structure No. 185 -- C H NO Structure No. 211 -- C H O
14 15 3 15 10 6
Structure No. 160 -- C H O
13 20 3
Structure No. 186 -- C H NO Structure No. 212 -- C H O
14 15 5 15 10 7
Structure No. 161 -- C H NO
13 21 3
Structure No. 187 -- C H O Structure No. 213 -- C H O
14 16 5 15 12 4
