Mass Spectral Data of Cyclooctyl Derivatives John R. Dixon, Gareth J. James, and lvor G. Morris’ Department of Chemistry, Glamorgan Polytechnic, Tretorest, Glamorgan, Great Britain
The mass spectra of some cyclooctyl derivatives are reported. The main fragmentation processes observed are loss of C2H5, loss of C2H4, and where appropriate, loss of water. High-resolution mass measurements define the exact composition of some of the principal fragment peaks.
In the course of work on bicyclononane derivatives, it was considered to be of interest to prepare some cyclooctyl derivatives and to examine their mass spectral fragmentations. The mass spectra of the prepared derivatives (Table I) reported here are: methylenecyclooctane (I), 5-methylenecyclooctene ( I I ) , 5-hydroxymethylcyclooctene (I I I ) , 5-formylcyclooctene (IV), 5-acetylcyclooctene (V), 5-propionylcyclooctene (VI), and cyclooctene-5-carboxylic acid (VI I). The cyclooctyl derivatives were prepared from 2 - ( N pyrrolidinyl)bicyclo13,3,l~nonan-9-ene. The conversions of the ketoamine to IV and VI1 have been described pre-
viously ( 7 , 3). The compounds V (2) and VI were prepared from the ketoamine by the method used for compound IV after reaction of the ketoamine with methyl magnesium iodide or ethyl magnesium iodide. Lithium aluminum hydride reduction of the methyl ester of VI1 afforded the hydroxymethyl compound (II I ) (2). The hydrocarbon ( I I) was prepared from the hydroxymethyl compound (I1I) by reaction with triphenyl phosphite and bromine. Treatment of the subsequent bromide with 2,4,6trimethylpyridine eliminated hydrogen bromide giving an exocyclic double bond. The saturated hydrocarbon (I) (2) was prepared in an analogous manner from 5-hydroxymethylcyclooctane, obtained from the carboxylic acid (VI I ) after catalytic hydrogenation, esterification, and lithium aluminum hydride reduction. All the compounds were purified by fractional distillation. The mass spectra were recorded at the PCMU, Harwell, England, on an AEI MS-902 spectrometer at an ionizing voltage of 70 eV. The accuracy of the high-resolution data is f0.005 over the range of mass values given. Results and Discussion
With the one exception of the carboxylic acid (VII), all the cyclooctyl derivatives gave a clear indication of the
’ To whom correspondence should be addressed. Table 1. Fragmentation Pattern of Cycloocty I Derivatives m/e
I
II
Ill
IV
V
VI
VI1
m/e
39 40 41 42 43 44 50 51 52 53 54 55 56 57 58 63 65 66 67 68 69 70 71 72 73 77 78 79 80 81 82 83 84 85
48 11 60 14 84 6
30 14 6 5
32 7 61 11 29 10
37 7 50 12 100 9
36 7 57 10 69 15
50 10 54 9 27
47
7
6
5
21 36 52 15 55 8
15 30 30 7 30 66
15 20 48
87 91 92 93 94 95 96 97 98 99 105 107 108 109 110 111 112 117 118 119 120 121 122 123 124 131 134 136 137 138 140 152 154 166
9 5 22 32 44 22 7 25 10
11 64 40 27 6
13 5 36 28 100 24 6
7 7
9
9 27 35 7
5 13 9 9
9 12 100 39 18 22 23 6 15 11 58 48 71 31 33 10 14
a 62 20 9 11 7 8 8 8 32 15 30 24 10 6
52
10 5 12 7 20 21 29
28 27 62
50 10 5 5 60 10 7 36 16
8 5 22 8 17 6 21 8
11 17 100 22 8 10
72 26
20
19 9 71 46 19 7 8 10
27 100 95 25 18
I
II
11
7
16 24 21 48
7 100 8
7
8 5
Ill
IV
31 17 42 39 10 12 17 5
28 22 9 11 12 9 12
10 24
6 5 6 26 8
31 8 7 15
v
VI
10 14 10
6 17 5 46 18 10 5 6 23
8
21 100 7 5 6 20
5 8 18 38 5
VI1 28 60
21
59
8 6
9 7 7
12
26 9
5P
7 24 7
4P 11
24 15 5
6
12 10P
58 18
61 9
9P 15P 4P 1P
Journal of Chemical and Engineering Data, Vol. 20, No. 1, 1975
123
loss of a C2H5 fragment upon electron impact. The loss of C2H5 from the ethyl ketone ( V I ) is no doubt due to both loss from the ring, as has occurred with the other compounds, and loss from the side chain. The corresponding loss of a methyl unit from the methyl ketone (V) was observed. Another linking feature of these ketones is the loss of H20 subsequent to the loss of the hydrocarbon fragment from the side chain. Compound (V) mle 152 Compound (VI) m/e 166
- -CH3
137
-C2H5
137
-H20
-H 0
-H2O
134
119
-
m/e 138
-C'2H5,
Metastable ions
I
68.3 77.1 104.4 105.7 89.0 120.2
Ill IV
V VI VI I
66.3 66.4 77.1 96.4 80.0 89.1
54.8 70.5 77.1 78.1 78.4
52.5 66.2 70.5
54.7 66.5
66.4
59.2
Table 111. High-Resolution Mass Measurement
CornCompound
m/e
position
IV
120 109 109 92 79 58 43 43 134 109 109 98 79 67 108 108 93 93 80 79 67
CgHiP CsHis C7HgO CTHs CaH7 CaHaO CsH7 CzHsO CioHii CsHia C7HgO CeHloO CBH, C5H7 CsH12 C7HsO C7Hs CGHSO CaHs CeH7
a 119
The ethyl ketone ( V I ) was the only oxygenated compound examined that did not lose water as an initial fragmentation process. The breakdown in the acid ( V I I ) is accompanied by the formation of a metastable ion at m / e 120.2 (Table 1 1 ) . High resolution (Table Ill) upon the (M-18) fragments of the aldehyde ( I V ) and the methyl ketone (V) show them to be due to hydrocarbon fragments only. The formation of the ion m / e (M-28) is apparent only in the two hydrocarbons (I and I I ) , the alcohol ( I l l ) , and the aldehyde ( I V ) . In the two oxygenated compounds this could be due to loss of CO. However, it could be due to the loss of C2H4 from the parent, or the sequential loss of H2 and C2H2, as is undoubtedly the case with the hydrocarbon ( I ) . The hydrocarbon ( 1 1 ) appears to lose CpHl from the parent, but here, contrary to the compounds just mentioned, there is a loss of 2H2 from the parent. Possibly, this is due to the fact that such a loss, with a rearrangement would bring the resulting double bonds formed into a cyclic conjugated system. This result could also account for the loss of 3H2 from the hydrocarbon ( I ) , m / e 124 122 118. The fragment ion at m / e 109 in the spectrum of the compounds I, I l l , IV, V, and V I has some duality associated with it. In the case of the hydrocarbon ( I ) , it is due to a straight loss of a methyl group. However, in the oxygenated compounds I l l , I V , V, and VI, it would appear to be due to loss of side chain or loss of a hydrocarbon fragment either directly as in ( I V ) , +
Compound
119
A metastable peak at m / e 105.7 corresponding to the breakdown m / e 137 to m / e 119 was observed in the spectrum of (V). The alternative sequence was only apparent in (V), i.e.,
mle I 5 2
Table II. Metastable Ions
109
V
VI1
CSH7
Multiplet ratio 1 1
1 2 2 1
'
4 1 4 1
Measd mass
Calcd mass
120.0935 109.1016 109.0647 92.0624 79.0546 58.0419 43.0549 43.0184 134.1095 109.1020 109.0655 98.0733 79.0549 67.0547 108.0941 108.0577 93.0704 93.0341 80.0624 79.0547 67.0550
120.0939 109.1017 109.0653 92.0626 79.0548 58.0419 43.0548 43.0184 134.1095 109.1017 109.0653 98.0732 79.0548 67.0548 108.0939 108.0575 93,0704 93.0340 80.0626 79.0548 67.0548
ative abundance of the oxygenated as opposed to the hydrocarbon fragment (Table I ) . Similarly, the ion m / e 108 in the spectra of compounds IV, V, VI, and VI1 could be due to the loss of a hydrocarbon fragment or of the side chain plus a hydrogen atom to give the molecules formaldehyde, acetaldehyde, propionaldehyde, and formic acid, respectively. That this latter process is the major route is shown by the multiplet ratios of the ions at m / e 108 (Table I I I ) . The alcohol ( I l l ) did not give rise to a fragment ion at m / e 108 corresponding to the loss of methanol which would bring its behavior into line with the other oxygenated compounds studied. Acknowledgment
or by a sequential process as indicated:
(ill) 140 (V)152 (V1)166
-138
-CH3
-C2H5
137
137
-C2H5
-C2H4
-C2H4
109 109 109
High resolution (Table I I I ) upon m / e 109 indicates that the structure of the parent has an influence upon the rel-
124
Journal of Chemical and Engineering Data, Vol. 2 0 , No. 1, 1975
The authors thank J. A. Winter for experimental assistance and the SRC for credit facilities enabling the spectra to be recorded at the PCMU, Harwell, England. Literature Cited (1) Dean, C. S.,Dixon, J. R . , Graham, S. H . , Lewis, D. 0.. J . Chem. SOC.(London), 1968, p 1491. (2) Graham, S. H., University College of Wales, Aberystwyth, G.B., private communication, 1974. (3) Stork, G., Landesman. H. K.. J . Amer. Chem. SOC.,7 8 , 5129 (1956)
Received for review March 28, 1974. Accepted September 23, 1974
