New aspects of nitrosation of arylcyclopropanes: Nitrosation of phenylcyclopropanes with bulky alkyl substituents in the small ring

Article abstract of DOI:10.1007/s10593-009-0184-z

It has been shown for the first time that nitrosation of phenylcyclopropanes with bulky alkyl substituents in the small ring proceeds predominantly with attack of the nitrosonium cation on the benzyl carbon atom of the cyclopropane ring with intermediate

Full text of DOI:10.1007/s10593-009-0184-z

Chemistry of Heterocyclic Compounds, Vol. 44, No. 10, 2008
NEW ASPECTS OF NITROSATION
OF ARYLCYCLOPROPANES: NITROSATION
OF PHENYLCYCLOPROPANES WITH BULKY
ALKYL SUBSTITUENTS IN THE SMALL RING
O. B. Bondarenko, A. Yu. Gavrilova, L. G. Saginova, N. V. Zyk, and N. S. Zefirov
It has been shown for the first time that nitrosation of phenylcyclopropanes with bulky alkyl substituents
in the small ring proceeds predominantly with attack of the nitrosonium cation on the benzyl carbon
atom of the cyclopropane ring with intermediate formation of an alkyl carbocation. In addition to
isoxazolines, 1,2-oxazines and ∆1-pyrroline N-oxide are formed, formation of the latter is preceded by
skeletal rearrangement.
Keywords: 1-alky-2-phenylcyclopropanes, isoxazolines, 1,2-oxazines, ∆1-pyrroline N-oxide,
nitrosation, skeletal rearrangement.
The synthesis of isoxazolines and isoxazoles by the nitrosation of arylcyclopropanes is the most
established method for the construction of these heterocycles, to a large extent facilitated by the search for
available and effective nitrosating reagents [1, 2]. Widening the range of nitrosating agents in these reactions
provided a new contribution to our ideas of the process of nitrosation and the conversion of such cyclopropanes.
Particular attention has been paid to the regiochemistry of the nitrosation of alkylcyclopropanes, directly
connected to the spatial interactions of substituents in the small ring.
It is known that in most cases nitrosation of 1,2-disubstituted cyclopropanes leads to the formation of a
mixture of isomeric isoxazolines [1, 3]. Thus on nitrosation of 1-methyl-2-phenylcyclopropane the basic
reaction product is 3-methyl-5-phenylisoxazoline, formed as a result of opening the C(1)–C(2) bond, while a
second isomer appeared, 4-methyl-5-phenylisoxazoline, formed by opening of the C(1)–C(3) bond, probably
caused by the formation of steric hindrance on introducing the nitroso group into the small ring. In this
connection we were interested in studying the nitrosation of a number of cyclopropanes containing bulky
substituents in the small ring. We chose 1-cyclohexyl- (1), 1-isopropyl- (2), and 1-tert-butyl-2-phenylcyclo-
propanes (3) as model substrates.
_______
* Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
__________________________________________________________________________________________
M. V. Lomonosov Moscow State University, Moscow 119991, Russia; e-mail:
bondarenko@org.chem.msu.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1566-1575,
October, 2008. Original article submitted May 30, 2008.
0009-3122/08/4410-1275©2008 Springer Science+Business Media, Inc.
1275

It was suggested that the large volume of the substituent at position 2 of the cyclopropane ring led to a
decrease in the fraction of the 3,5-disubstituted isoxazoline, the product of opening the C(1)–C(2) bond, and on
increase in the fraction of the corresponding 4,5-isomer, product of opening the C(1)–C(3) bond.
The results we have obtained were unexpected: an increase in the size of the substituent in the small ring
led not only to an increase in the content of the 4,5-disubstituted isoxazoline in the reaction mixture, but also to
the appearance of atypical products of nitrosation of arylcyclopropanes with opening of the 1,2-disubstituted
bond and attack of the nitrosonium cation at the benzyl carbon atom.
For example, in the case of cyclopropane 1 the isomeric isoxazolines 4a-c were isolated from the
reaction mixture, compound 4c being as the main product. It should be noted that products of nitrosation of
arylcylopropanes resulting from attack of the nitrosonium cation on the benzyl carbon atom of the small ring has
not been reported in the literature before.
.
NOCl 2SO3
Ph
Hex-c
CH2Cl2, 0°C
1
Ph
Ph
Ph
Hex-c
Hex-c
Hex-c
O
+
O
+
N
N
N
O
4b (25%)
4c (40%)
4a (26%)
The structures of compounds 4a-c were determined from the chemical shifts and multiplicities of the
signals in the 1H NMR spectra.
In the spectra of compounds 4a,c and 4b a set of signals of the isoxazoline ring were present as ABM
and AMX systems respectively. The signals of the CHO proton in the 5.0-6.0 ppm field are characteristic for
each isomer. For isomers 4a and 4c it appears as a doublet of doublets with two vicinal constants of the order of
8-10 Hz. In isomer 4c a complication of the signal of the CHO proton is observed as a result of interaction with
the protons of the alkyl substituent (an additional coupling constant of 6.8 Hz), while in the isomer 4b the signal
of the CHO appears as a doublet. In addition in the spectrum of isomer 4b there is a signal of the CH=N proton
at weak field which is absent for isomers 4a and 4c. The chemical shifts and multiplicities of the remaining
signals correspond to the proposed structures (Table 1).
Ph
Pr-i
Ph
.
NOCl 2SO3
i-Pr
+
O
O
+
Ph
Pr-i
5a (33%)
CH2Cl2, 0°C
N
N
2
5b (50%)
O
Ph
Ph
Me
Me
+
+
+
N
N
Pr-i
O
O
Pr-i
7 (5%)
6 (5%)
5c (5%)
1276

1277

Table 2. 13C NMR Spectra of Isoxazolines 4a-c, 5a-c, 8b
Chemical shifts, δ, ppm
Com-
pound
Aromatic carbon atoms
CH2
CHO
C=N
Other atoms
С(2)H, С(3)H,
C(6)H C(5)H
СHR
С-1
С-4
4a
5a
81.0
81.3
157.5
163.1
141.4
141.4
128.5
128.7
125.5
125.7
127.7
128.0
25.8 (3CH2), 26.0, 30.4,
37.25 (CH)
43.3
63.9
64.7
69.2
42.5
20.1 (2СН3),
27.9 (СН(СН3)2)
4b
5b
8b
4c
83.4
83.5
81.5
85.8
147.8
147.8
145.5
156.4
141.7
141.6
142.4
126.2
128.7
128.7
125.1
128.7
125.6
125.5
128.6
126.6
127.9
128.0
127.6
129.9
26.01, 26.04, 26.20,
30.7, 31.0, 40.1 (CH)
19.9 (СН3), 20.3 (СН3),
30.3 (СН(СН3)2)
27.5 (3СН3),
33.1 (Сquat),
25.7, 25.9, 26.3, 28.6,
31.9 (СH), 37.4
More complex mixtures of reaction products were obtained from the nitrosation of 1-isopropyl- and
1-tert-butyl-2-phenylcyclopropanes. In the case of hydrocarbon 2 the isoxazolines 5a and 5b were isolated as
the main components, with the amount of 5b exceeding that of 5a by a half. Small quantities of the isoxazoline
5c, the oxazine 6, and 3-isopropylindanone-1(7) were also formed.
In the case of hydrocarbon 3 only 5% of the isoxazoline 8a was isolated, the amount of isoxazoline 8b
isolated corresponded to 20% of the initial cyclopropane, 5-tert-butyl-3-phenylisoxazoline was not observed
among the reaction products. The main reaction products were the corresponding oxazine 9 (30%) and the
pyrroline N-oxide 10 (30%). Small quantities of a fraction consisting of a mixture of the oxime 11 and the
ketones 12, 13 were also isolated.
Ph
Bu-t
Ph
Ph
Me
+
Me
Me
9 (30%)
+
+
Bu-t
+
N
O
O
Ph
Bu-t
O
N
N
3
8a (5%)
8b (20%)
NOH
Me
Ph
Ph
Me
Me
Ph
Me
Me
Me
10 (30%)
Cl
+
+
+
Me
O
O
N
Me
Me
Me
Me
11 (2.5%)
Me
O
13 (5%)
12 (2.5%)
The composition and structures of compounds 6, 7, 9-13 were established on the basis of NMR and IR
spectroscopy, mass spectrometry, and elemental analyses.
Oxazine 9 was isolated in the pure state, while compound 6 was characterized in a mixture with
isoxazoline 5b. The m/z molecular ion values of compounds 6 and 9 are respectively 189 and 203, i.e., these
compounds are structural isomers of the corresponding isoxazolines 5 and 8. Analysis of the chemical shifts and
1278

multiplicities of the signals of the aliphatic portion of the 1H NMR spectra shows the change in structure of the
alkyl substituent which in this case can only arise if the reaction center is the carbon atom bonded to the
substituent. Fragmentation of the molecular ions corresponds to the structures 6 and 9.
In the case of cyclopropane 3 a single compound with a molecular ion [M]+ 203 and a small value of Rf
was isolated in pure form. The character and multiplicity of the proton signals were identical with those of
oxazine 9, but were shifted by 0.3-0.5 ppm to weak field. We assigned structure 10 to this compound. The data
of the 1H NMR spectrum of the isolated compound did not disagree with the proposed structure 10.
The ketone 7 was isolated in pure form, while oxime 11 was characterized in a mixture with compounds
12 and 13. A carbonyl absorption at 1690 cm-1 appears in the IR spectrum of compound 7. The signal of the
C=O carbon appears at 198.2 ppm in its 13C NMR spectrum.
The IR spectrum of the first fraction isolated from the reaction mixture obtained from the nitrosation of
hydrocarbon 3 showed the presence of an oxime unit and a carbonyl group (1690, 3300-3500 cm-1). Chromato-
mass spectroscopic analysis of the mixture of these compounds, taking into account the multiplicities and
integrated intensities of the proton signal in the 1H NMR spectrum permitted the assignments of structures 11-13
to these compounds.
1
In their H NMR spectra the signals of the protons of the CH2 group of compounds 7 and 11 appear as
doublets of doublets with large geminal couplings of ~ 17 Hz and vicinal couplings within the limits of 4.5 and
9.5 Hz. The signal of the H-3 proton for ketone 7 and oxime 11 are multiplets appearing at 2.83 and 2.22 ppm
respectively. In the indanone 7 it is shifted to lower field because it is found in the benzyl position relative to the
aromatic ring. The isopropyl fragment is retained in ketone 7, whereas in the spectrum of compound 9 signals of
three different methyl groups are observed which indicated the rearrangement of the hydrocarbon skeleton. The
character of the signals of the aromatic region in the 1H and 13C NMR spectra indicate the presence of an ortho
substituent in the aromatic ring.
Despite the various structures of compounds 6, 7, and 9-13 , they are all formed as a result of an initial
attack of the nitrosonium cation at the benzyl carbon atom of the small ring with subsequent opening of the
1,2-disubstituted bond of the cyclopropane ring and formation of a carbocation center (C). Subsequently
different stabilization of the intermediate is possible: by participation of an internal nucleophile (the oxygen of
the nitroso group – the 1,2-oxazines 6 and 9, the nitrogen atom of the nitroso group – the ∆1-pyrroline N-oxide
10), an external nucleophile (a chlorine atom – ketone 12), elimination of a proton (unsaturated ketone 13), or
electrophilic attack of a carbocation on the aromatic ring (ketone 7, oxime 11). We note that, in the case of the
tert-butyl radical, all of the following conversions precede skeletal rearrangement with participation of the
substituent with formation of a stable tertiary carbocation D, which is analogous to the hydride shift which
precedes the cyclization for the formation of oxazine 6.
Thus the whole range of compounds obtained as a result of nitrosation of hydrocarbons 2 and 3,
including isoxazolines 5a,b and 8a,b, are formed from the carbocations A and B respectively, can be described
by the scheme on the p. 1280.
It follows from these studies that with increasing size of the alkyl substituent in 1-alkyl-2-phenyl-
cyclopropanes spatial factors play role and the attack of the nucleophile predominates at the unsubstantiated
carbon on the small ring (the yield of the 4,5-disubstituted isoxazoline is equal to or exceeds the yield of the
3,5-disubstituted isomer in the case of hydrocarbons 1 and 2, 3 respectively). In the isopropyl, cyclohexyl, and
tert-butyl series of substituents the preference for the attack of the nitrosonium cation at the benzyl carbon atom
of the smaller ring with opening of the C(1)–C(2) bond increases: the overall yield of products formed as a result
of this reaction is 10, 40, and 74% respectively. The solution to the question whether this is connected only with
the size of the substituent or is associated with the influence of other factors requires further investigation.
1279

1280

EXPERIMENTAL
1
The H and 13C NMR spectra of CDCl3 solutions with HMDS (δ 0.05 ppm) as internal standard were
recorded on a Bruker Avance 400 instrument (400 and 100 MHz respectively). IR spectra of nujol mulls or thin
films were recorded on UR-20 spectrometer, mass spectra were recorded on Finnigan MAT SSQ 7000 chromato-
mass spectrometer, ionization energy 70 eV, quartz capillary column OV-1 (25 m), temperature regime: 70 (2 min)
-20 (1 min) -280°C (10 min). Elemental analyses of the compounds synthesized were determined on a Carlo-Erba
CHN-analyzer. Melting points were determined on a block in open capillaries. Rf values were determined on Silufol
plates in 1:10 ethyl acetate–petroleum ether (compounds 4-9, 11-13) or 2:1 ethyl acetate–petroleum ether (compound
10).
The phenylcyclopropanes 1-3 were synthesized by a known method by decomposition of the
corresponding pyrazolines [4] and were used in reactions as a mixture of the cis and trans isomers.
Syntheses of Isoxazolines from Arylcyclopropanes and NOCl·2SO3 (General Method). An
equimolar quantity of an arylcyclopropane in methylene chloride (2ml) was added to a suspension of
NOCl·2SO3 (1 mmol) in methylene chloride (10 ml) at 0°C. The solid dissolved partially and the solution
became colored. At the end of the reaction (monitored by TLC) the reaction mixture was neutralized with
sodium carbonate solution and washed with water. The water layer was extracted with methylene chloride (3×10
ml), the extract was dried with Na2SO4, the solvent was evaporated, and the reaction products were isolated
chromatographically.
Compounds 4a-c were prepared by the reaction of 2-cyclohexyl-1-phenylcyclopropane (1) (400 mg,
2 mmol) and NOCl·2SO3 (450 mg, 2 mmol) for 2 h at 0°C after standard treatment of the reaction mixture and
chromatographic isolation on a column (SiO2 40/100, 1:10 ethyl acetate–petroleum ether).
3-Cyclohexyl-5-phenylisoxazoline (4a). Yield 134 mg (26%). Rf 0.40. Mass spectrum, m/z (Irel, %): 229
[M]+ (37), 161 (89), 117 (14), 104 (100), 91 (17), 83 (8), 77 (13), 55 (13).
4-Cyclohexyl-5-phenylisoxazoline (4b). Yield 129 mg (25%). Rf 0.42. Mass spectrum, m/z (Irel, %): 229
[M]+ (77), 186 [M-HCNO]+ (35), 146 [M-C6H11]+ (100), 130 (97), 117 (28), 107 (88), 104 (85), 91 (42), 83 (40),
55 (62).
5-Cyclohexyl-3-phenylisoxazoline (4c). Yield 206 mg (40%). Rf 0.44. IR spectrum, ν, cm-1: 1675
(C=N), 1600. Mass spectrum, m/z (Irel, %): 229 [M]+ (44), 146 [M-C6H11 ]+ (100), 118 (62), 104 (16), 91 (42), 77
(33), 55 (18).
Compounds 5a-c, 6, and 7 were obtained as a result of the reaction of 1-isopropyl-2-phenylcyclopropane
(2) (473 mg, 3 mmol) and NOCl·2SO3 (677 mg, 3 mmol) for 2 h at 0°C after standard work-up of the reaction
mixture and chromatographic separation on a column (SiO2 40/100, 1:10 ethyl acetate–petroleum ether).
3-Isopropyl-5-phenylisoxazoline (5a). Yield 180 mg (33%). Rf 0.25. Found, %: C 76.25; H 8.10;
N 7.26. C12H15NO. Calculated, %: C 76.19; H 7.94; N 7.41.
4-Isopropyl-5-phenylisoxazoline (5b). Yield 280 mg (50%). Rf 0.31. Mass spectrum, m/z (Irel, %): 189
[M]+ (55), 146 [M-HCNO]+ (55), 131 [M-HCNO-CH3]+ (100), 115 (27), 107 (51), 91 (52), 77 (36), 51 (12).
Found, %: C 76.29; H 7.75; N 7.65. C12H15NO. Calculated, %: C 76.19; H 7.94; N 7.41.
6,6-Dimethyl-3-phenyl-5,6-dihydro-4H-1,2-oxazine (6) (isolated and characterized in a mixture with
isoxazoline 5b). Yield 28 mg (5%). Rf 0.29. 1H NMR spectrum, δ, ppm (J, Hz): 1.33 (6H, s, 2CH3); 1.90 (2H, t,
J = 7.0, CH2); 2.60 (2H, t, J = 7.0, CH2); 7.40 (3H arom, m); 7.74 (2H arom, m). 13C NMR spectrum, δ, ppm:
15.6 (2CH3); 19.7 (CH2); 29.6 (CH2); 73.83 (CO); 125.2, 128.4, 129.2 (C- 4); 136.09 (C-1); 152.87 (C=N).
Mass spectrum, m/z (Irel, %): 189 [M]+ (100), 174 [M–CH3]+ (72), 130 [M-CH3-CH3CHO]+ (44), 117
,
[PhCNCH2]+ (19), 103 [PhC=N]+ (63), 77 (54).
5-Isopropyl-3-phenylisoxazoline (5c). Yield 25 mg (5%) (separated and characterized in a mixture with
ketone 7). Rf 0.40, Mass spectrum, m/z (Irel, %): 189 [M]+ (33), 146 [M-i-Pr]+ (22), 118 (100), 104 (17), 91 (39),
77 (74), 51 (46).
1281

3-Isopropylindanone-1 (7). Yield 26 mg (5%). Rf 0.42. IR spectrum, ν, cm-1: 2970-2890, 1690 (C=O),
1
1605, 1460, 1310, 1290, 775. H NMR spectrum, δ, ppm (J, Hz): 1.12 (3H, d, J = 6.9, CH3); 1.43 (3H, d,
J = 7.0, CH3); 2.18 (1H, m, HC(CH3)2); 2.43 (1H, dd, J = 17.0, J = 7.0, CH2); 2.83 (1H, m, i-Pr-CH); 2.89 (1H,
dd, J = 17.0, J = 4.5, CH2); 7.32 (1H, dt, J = 7.8, J = 0.6, H-6 arom); 7.36 (1H, d, J = 7.8, H-4 arom); 7.53 (1H,
dt, J = 7.8, J = 1.4, H-5 arom); 8.03 (1H, dd, J = 7.8, J = 1.4, H-7 arom). 13C NMR spectrum, δ, ppm: 20.3
(CH3); 20.6 (CH3); 35.4 (C(CH3)2); 39.9 (i-Pr-C); 43.4 (CH2); 126.4, 126.7, 128.3, 131.6 (Cquat); 133.9, 147.7
(Cquat); 198.2 (C=O). Mass spectrum, m/z (Irel, %): 174 [M]+ (50), 159 [M-CH3]+ (43), 132 (100). 131 (74), 115
(30),104 (84), 91 (27), 78 (47), 51 (41). Found, %: C 82.89; H 8.20. C12H14O. Calculated, %: C 82.76; H 8.05.
Compounds 8a,b, 9-13 were obtained as a result of the reaction of 1-tert-butyl-2-phenylcyclopropane
(3) (470 mg, 2.7 mmol) and NOCl·2SO3 (677 mg, 3 mmol) for 2 h at 0°C after standard work-up of the reaction
mixture and column chromatographic separation (SiO2, 40/100, 1:10 ethyl acetate–petroleum ether). Rf 0.54.
3-tert-Butyl-5-phenylisoxazoline (8a). Yield 25 mg (5%). Rf 0.30.
4-tert-Butyl-5-phenylisoxazoline (8b). Yield 110 mg (20%). Rf 0.36. IR spectrum, ν, cm-1: 1680 (C=N),
1600. Mass spectrum: m/z (Irel, %): 203 [M]+ (40), 147 [M – t-Bu]+ (87), 130 (100), 115 (19), 105 (15), 77 (18),
57 (t-Bu) (75).
5,6,6-Trimethyl-3-phenyl-5,6-dihydro-4H-1,2-oxazine (9). Yield 160 mg (30%). Rf 0.32. IR spectrum,
1
3
ν, cm-1: 1660 (C=N), 1595. H NMR spectrum, δ, ppm (J, Hz): 1.06 (3H, d, J = 6.8, CH3); 1.15 (3H, s, CH3);
3
2
3
1.38 (3H, s, CH3); 2.00 (1H, m, CHCH3); 2.15 (1H, dd, J = 9.9, J = 18.2, CH2); 2.62 (1H, dd, J = 5.9,
2J = 18.2, CH2); 7.34 (3H arom); 7.70 (2H arom). 13C NMR spectrum, δ, ppm: 16.76 (CH3); 18.82 (CH3); 25.74
(CH3); 27.80 (CH2); 32.82 (CH); 77.18 (CO(CH3)2); 125.04 (C-2,3 arom); 128.17 (C-2,3 arom); 128.91 (C-4
arom); 136.02 (C-1 arom); 153.50 (C=N). Mass spectrum, m/z (Irel, %): 203 [M]+ (70), 188 [M-CH3]+ (5), 160
(10), 144 (36), 130 (100), 118 (84), 104 (65), 103 (58), 77 (40), 59 (28), 43 (21).
4,5,5-Trimethyl-2-phenyl-∆1-pyrroline N-Oxide (10). Yield 160 mg (30%). Rf 0.41. IR spectrum, ν,
cm-1: 2980-2940, 2860, 1540, 1450, 1370, 1220. 1H NMR spectrum, δ, ppm (J, Hz): 1.17 (3H, d, 3J = 6.9, CH3);
3
2
1.28 (3H, s, CH3); 1.47 (3H, s, CH3); 2.31 (1H, m, CHCH3); 2.62 (1H, dd, J = 9.2, J = 16.3, CH2); 3.15 (1H,
dd, 3J = 8.0, 2J = 16.3, CH2); 7.41 (3H arom); 8.83 (2H arom). 13C NMR spectrum, δ, ppm: 14.81 (CH3); 19.49
(CH3); 25.15 (CH3); 35.17 (CH2); 37.34 (CH); 77.59 (NC(CH3)2); 127.01 (C-2,3 arom); 128.13 (C-2,3 arom);
129.43 (C-4 arom); 129.92 (C-1 arom); 136.19 (C=N). Mass spectrum, m/z (Irel, %): 203 [M]+ (90), 188
[M-CH3]+ (26), 171 (12), 118 (41), 103 (100), 91 (19), 83 (45), 77 (59), 55 (31), 41 (49).
3,4,4-Trimethyl-3,4-dihydronaphthalin-1(2H)-one Oxime (11) (separated and characterized in a
1
3
mixture with ketones 12 and 13). H NMR spectrum, δ, ppm (J, Hz): 1.07 (3H, d, J = 6.9, CH3); 1.44 (6H, s,
3
2
3
2
2CH3); 2.22 (1H, m, CHCH3); 2.55 (1H, dd, J = 9.5, J = 17.4, CH2); 2.79 (1H, dd, J = 4.5, J = 17.4, CH2);
7.31 (1H arom); 7.47 (1H arom); 7.55 (1H arom); 8.04 (1H arom). Mass spectrum, m/z (Irel, %): 203 [M]+ (33),
170 (60), 160 (19), 141 (56), 118 (100), 105 (40), 83 (34), 57 (20).
3,4,4-Trimethyl-1-phenylbuten-3-one (12) (separated and characterized in a mixture with ketone 13
and oxime 11). 1H NMR spectrum, δ, ppm (J, Hz): 1.29 (6H, s, 2CH3); 1.59 (3H, s, CH3); 3.13 (1H, d, 3J = 16.5,
CH2); 3.38 (1H, d, 3J = 16.5, CH2); 7.41 (3Harom); 7.68 (2Harom). Mass spectrum, m/z (Irel, %): 188 [M]+ (5), 173
(9), 147 (81), 146 (50), 130 (100), 117 (11), 115 (24), 77 (25), 83 (43), 57 (66).
3-Chloro-3,4,4-trimethyl-1-phenylbutanone (13) (isolated and characterized in a mixture with ketone 12
and oxime 11). 1H NMR spectrum, δ ppm (J, Hz): 0.99 (3H, d, 3J = 6.84, CH3); 1.04 (3H, d, 3J = 6.75, CH3); 1.40
2
2
(3H, s, CH3); 2.93 (1H, d, J = 16.6, CH2); 3.21 (1H, d, J = 16.6, CH2); 7.41 (3H arom); 7.68 (2H arom). Mass
spectrum, m/z (Irel, %): 224 [M]+ (5),188 (53), 173 (100), 145 (61), 131 (81), 117 (26), 105 (11), 103 (11), 77 (11).
This work was carried out with a subvention from the Russian Fund for Fundamental Research (grant no.
08-03-00707-a) and the Russian Academy of Sciences program "Theoretical and Experimental Study of the
Nature of Chemical Bonds and Chemical Processes".
1282

REFERENCES
1.
2.
3.
4.
R. A. Gazzaeva, Yu. S. Shabarov, and L. G. Saginova, Khim. Geterotsikl. Soedin., 738 (1983). [Chem.
Heterocycl. Comp., 19, 589 (1983)].
O. B. Bondarenko, A. Yu. Gavrilova, L. G. Saginova, N. V. Zyk, and N. S. Zefirov, Izv. Akad. Nauk,
Ser. Khim., 741 (2003).
R. A. Gazzaeva, Yu. S. Shabarov, and L. G. Saginova, Khim. Geterotsikl. Soedin., 309 (1984). [Chem.
Heterocycl. Comp., 20, 246 (1984)].
N. M. Kizhner, Zhurn. Russ. Fiz.-Khim. Obshch., 44, 863 (1912).
1283