Oxidative addition of N-aminophthalimide to conjugated and nonconjugated alkylazoalkanes

Article abstract of DOI:10.1007/s11178-005-0145-7

A series of γ,δ-unsaturated azo compounds was prepared by thermal isomerization of allylalkylhydrazones obtained from the simplest carbonyl compounds. The oxidation of N-aminophthalimide with lead tetraacetate in the presence of these unsaturated compound

Full text of DOI:10.1007/s11178-005-0145-7

Russian Journal of Organic Chemistry, Vol. 41, No. 2, 2005, pp. 204-213. Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005,
pp. 214-223.
Original Russian Text Copyright Ó 2005 by Kuznetsov, Belov, Buchaka.
Oxidative Addition of N-Aminophthalimide to Conjugated
and NonconjugatedAlkylazoalkanes
M.A. Kuznetsov1, V.N. Belov1,2, and S.M. Buchaka1
1 St. Petersburg State University, St. Petersburg, 198904 Russia
e-mail: mak@org.chem.lgu.spb.su
..
2 Institut fur organische und biomolekulare Chemie, Georg-August-Universitaet,
Tammannstrasse 2, D-37077 Goettingen, German
Received May 27, 2004
Abstract—A series of g,d-unsaturated azo compounds was prepared by thermal isomerization of allylalkyl-
hydrazones obtained from the simplest carbonyl compounds. The oxidation of N-aminophthalimide with lead
tetraacetate in the presence of these unsaturated compounds gave rise to mixtures of adducts at the azo group,
regioisomers of phthalimidoazimines. The oxidative addition of N-aminophthalimide to 1-isopropylazocycloalkenes
afforded bicyclic C-isopropylazo-N-phthalimidoaziridines, but the same reaction with 2-alkylazopropenes did not
result in any adducts with these conjugated azocompounds.
We recently demonstrated that oxidation of N-amino-
phthalimide (I) with lead tetraacetate in the presence of
conjugated phenylazoalkenes and also of cyclic azoalk-
ene, 3,3,5-trimethyl-3H-pyrazole, furnished a wide range
of compounds: C-azoaziridines, phthalimidoazimines,
2H-1,2,3-triazole derivatives etc. [1, 2]. However our first
attempts to bring 2-alkylazopropenes into this reaction
were unsuccessful, although with g,d-unsaturated azo
compounds we obtained the corresponding unsaturated
phthalimidoazimines [3]. Therefore we believe that
a closer look at the oxidative addition of N-aminophthal-
imide to a series of conjugated and nonconjugated
alkylazaalkenes is called for. We selected for the study
4-alkylazo-1-alkenes IIa–IIe in whose structure the
mutual influence of the C=C and N=N bonds was
negligible, and also 2-alkylazo-propenes IIIa, IIIb and
1-iso-propylazocycloalkenes IVa, IVb with a conjugated
bond system C=C–N=N.
To the preparation of homoallyl azo compounds IIa–
IIe we applied the [3,3]-sigmatropic rearrangement of
alkylallylhydrazones [4]. Initial hydrazones Va–Ve were
obtained from primary amines, allyl bromide, and carbonyl
compounds along the common procedure.
The rearrangement of alkylallylhydrazones Va–Ve into
g,d-unsaturated azo compounds IIa–IIe was performed
by heating the initial hydrazones in sealed ampules at 170–
185°C for 20–35 h. In keeping with [4] the rearrangement
rate decreased at the growing number of substituents in
the carbonyl moiety. In the course of formaldehyde
allylmethylhydrazone (Va) isomerization the reaction
5
=Qꢀ+Jꢁ
+&O
5
5
$OO%U
1D12
1+
5
1 12
1 1+
5
1+
9,,Dꢀꢁ9,,E
1 1
&5 5
5 5 & 2
5
'
>ꢂꢃꢂ@
1 1
5
5
9D 9H
,,D ,,H
VI,VII, R1 = Me (a), i-Pr (b); II,V, R1 = Me, R2 = R3 = H (a), Me (b); R1 = i-Pr, R2 = H, R3 = H (c), Me (d), R2 = R3 = Me (e).
1070-4280/05/4102-0204Ó2005 Pleiades Publishing, Inc.

OXIDATIVE ADDITION OF N-AMINOPHTHALIMIDE
205
mixture often suffered tarring, and then the yield of
azoalkene IIa sharply decreased. In the other cases the
yield of the azo compound depended mainly on the length
of heating time; therewith the clean and relatively fast
isomerization of allylisopropylhydrazones of formaldehyde
(Vc) and acetaldehyde (Vd) (20–30 h, 180°C) yielded
virtually individual azo compounds IIc, IId (>95%
according to GLC data). However at the isomerization
under the same conditions of acetone allylisopropyl-
hydrazone (Ve) after ~25 h of heating the sealed ampules
twice exploded apparently due to decomposition of the
reaction product. In further experiments in the course of
this hydrazone isomerization we cautiously opened the
ampule after every 10–14 h of heating, flushed it with
inert gas, and sealed again. In this way we succeeded to
prepare also azo compound IIe.
5
1
1
1 1
,9Dꢀꢁ,9E
,,,Dꢀꢁ,,,E
azocyclohexene (IVb) was obtained in dichloromethane
at the use of potassium carbonate as dehydrating agent
in an almost quantitative yield, but the yield of the less
stable 1-isopropylazocyclopentene (IVa) under these
conditions attained only 25%. We succeeded in raising
the yield of azo compound IVa twofold by using as solvent
ethyl ether and as dehydrating agent the neutral sodium
sulfate. 1-Isopropyl-azo-cycloalkenes IVa, IVb prepared
by us for the first time are greenish viscous fluids with a
sweetish odor that decompose at room temperature. Their
structure expected for the given method of synthesis was
confirmed by the 1H and 13C NMR spectra.
As a result of theses syntheses were isolated and
characterized for the first time nitrosamines VIa, VIb
{allylmethylnitrosamine (VIa) had been formerly used
without purification for preparation of the respective
hydrazine [4]}, 1-allyl-1-isopropylhydrazine (VIIb),
hydrazones Vc–Ve, and three isopropylazoalkenes IIc–
IIe. Their structure follows from the synthesis method
and is confirmed by the sum of physicochemical and
spectral characteristics. The mass spectra of hydrazones
Vc–Ve we synthesized were presented and discussed
in [5].
The oxidative addition of N-aminophthalimide (I) to
g,d-unsaturated azo compounds IIa–IIe was carried out
by bringing lead tetraacetate in a dispersion of imide I
and potassium carbonate in a solution of the azo compound
in CH2Cl2. From the reaction mixtures obtained with
substrates IIa, IIc, IId we succeeded to isolated by
column chromatography substances characterized by
similar values of Rf (0.35–0.50 in a system benzene–
ethyl acetate, 7:1, SiO2) which were yellow oily sub-
stances slowly crystallizing on standing. The sum of their
characteristics shows that in these cases in 15–50% yields
were obtained mixtures containing regioisomers resulting
from oxidative addition of the N-aminophthalimide to the
1
In the H NMR spectra of azo compounds IIc–IIe
a single set of signals from substituents was present. It
means that these compounds are formed as a single
spatial isomer and apparently they belong to the (E) series
1
(cf. [4]). In the H NMR spectra of nitrosamines VIa,
VIb two sets of signals are observed due to the partially
double character of the N–N bond resulting in appearance
of the corresponding syn- and anti-isomers. It is
presumable that in both cases the isomer prevails where
the oxygen is nearer to the less bulky substituent (Me in
VIa, All in VIb). Then the comparison of the chemical
shift values for the respective pairs of signals shows that
the N=O group exerts shielding effect on the protons of
the syn-located substituent.
5
3L1
1
3L1 1+
1
1
,
,,D ,,H
3Eꢀ2$Fꢁ
5
9,,,D 9,,,F
5
3L1
1
1
1
Conjugated alkylazoalkenes III and IV were prepared
from the corresponding alkylhydrazines and a-chloro-
ketones by procedure [6] slightly modified for 1- isopropyl-
azocycloalkenes IV. By the example of compound IVb
synthesis we found that cooling to –20...–15°C at the
moment of reagents mixing and isolation of the reaction
product by column chromatography provided better yield
of the unsaturated azo compound.As a result 1-isopropyl-
5
,;D ,;F
VIII, IX, R1 = Me, R2 = H (a);
R1 = i-Pr, R2 = H (b), Me (c).
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 2 2005

206
KUZNETSOV et al.
adducts across the C=C bond, the corresponding phthal-
imidoaziridines. Actually, to the phthalimidoaziridine
structure should correspond not only the presence in
azo group, (1Z,2E)-1-alkenyl-2-alkyl- (VIIIa–VIIIc) and
(1Z,2E)-2-alkenyl-1-alkyl-3-phthalimidoazimines (IXa–
IXc).
1
the H NMR spectra of characteristic multiplets of the
The elemental analyses really show that these
compounds are adduct of imide I with homoallyl azo
compounds, 1:1. In their 1H NMR spectra apart from the
downfield signal of the phthalimide fragment in the region
4.9–6.2 ppm appears a characteristic multiplet of olefin
protons from the allyl group whose presence is additionally
confirmed by the signal of its methylene protons
(~2.6 ppm) and the corresponding signals in the 13C NMR
spectrum of azimines VIIIa+ IXa mixture. Inasmuch as
the allyl group in the compounds is retained, the reaction
obviously proceeds at the N=N bond affording phthal-
imidoazimines VIII+ IX.This assumption is confirmed by
signals of protons contiguous to nitrogens characteristic
of azimines in the region 3.5–4.9 ppm.
aziridine protons in the region 2.5–4.5 ppm, but also a sig-
nificant upfield shift of the methylene protons of the
previous allyl fragment (from ~2.6 to 1.5–1.8 ppm).
1
Inasmuch as no signals appear in this region of the H
NMR spectra of the reaction mixtures, we can conclude
that even if the phthalimido-aziridines form their amounts
are insufficient to be detected by 1H NMR spectroscopy,
TLC, and to be isolated preparatively. It may be
rationalized by reminding that the oxidative addition of
N-aminoheterocycles to a nonconjugated terminal C=C
bond of 1-alkenes usually occurs to an insignificant extent
(cf. [9]).
From the reaction mixtures obtained with compounds
IIb, IIe having a tertiary substituent at the azo group we
failed to isolate both phthalimidoazimines and phthalimido-
aziridines. In these cases we obtained as the main product
phthalimide arising due to oxidation of aminoimide I in
the absence of any reactive [10]. The similar chromato-
graphic behavior of all phthalimidoazimines obtained from
azoalkenes IIa, IIc, IId suggests that the corresponding
adducts with azo compounds IIb, IIe either do not form
at all or are unstable under the isolation conditions.
The position of substituents in the azimine fragment
1
was deduced from the H NMR spectra. As already
mentioned [7, 8], the signals of the a-protons of alkyl
groups attached to the central nitrogen of the azimine
system, on the one hand, and those at the N1 atom, on
the other hand, are present in essentially different regions
of the spectrum, and the position of these signals is virtually
insensitive to the geometry of the molecule or to the kind
of the substituent at the neighboring nitrogen atom. The
comparison of chemical shifts corresponding to these
protons in adducts VIII + IX with the chemical shifts of
the relevant protons for 1,2-dialkyl-3-phthalimidoazimines
described in the literature [7, 8] suggests that the main
reaction products VIIIa, VIIIc, IXb contain the smaller
substituent at the central nitrogen of the azimine system,
and in the minor products this substituent is attached to
the terminal nitrogen atom.
Thus the oxidative addition of aminoimide I to g,d-un-
saturated azo compounds II occurs only at the azo group
affording the corresponding phthalimidoazimines VIII +
IX. No wonder that the reaction follows the rules which
we have established for the series of (E)-azoalkanes [7,
11]: The reaction proceeds stereospecifically, with reten-
tion of azo group configuration, and regioselectively,
affording predominantly adducts containing the smaller
substituent at the central nitrogen of the azoimine system.
The decisive role belongs here apparently to the steric
effect of the substituents. With their growing bulk the
yield decreases, and the presence of a tertiary substituent
at the N=N bond prevents the adduct formation (Cf. [7,
11]). The specific effect of the alkenyl substituent is
manifested only in formation in some experiments with
substrates IIb–IId of unidentified products of pronounced
oligomeric character.
Each of the regioisomeric phthalimidoazimines formed
as a single stereoisomer. Therewith the chemical shifts
of alkyl protons virtually coincide with the corresponding
values in the spectra of already described (1Z,2E)-1,2-
dialkyl-3-phthalimidoazimines [7, 8]. At the same time
the change in the geometry of the molecule is usually
reflected in significant shift of the signals in the 1H NMR
spectra [7, 8]. This fact permits attribution of adducts
VIII + IX to the same series of stereoisomers as the
main products of the oxidative addition of imide I to the
(E)-azoalkanes, namely, to (1Z,2E)-azimines.
The reactions with conjugated azoalkenes IIIa, IIIb
were performed by the same procedure as with substrates
II. On completion of the reaction the precipitate of
inorganic salts was filtered off and washed with
dichloromethane. The filtrate was green-yellow, and its
color was considerably different from the bright yellow
one of the initial azo compound. On storage of this solution
In the 1H NMR spectra of reaction mixtures obtained
with substrates IIa, IIc, IId no significant additional
signals were observed as compared to the spectra of
azimines VIII + IX. This fact evidences the lack of
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 2 2005

OXIDATIVE ADDITION OF N-AMINOPHTHALIMIDE
207
at 5°C for 24 h no precipitate separated, and the char-
acteristic color remained. In the cases of both initial
compounds the evaporation of the filtrate obtained from
the reaction mixture we isolated only two products:
phthalimide (70–75%) and a colorless powdery substance
that decomposed at ~150°C, was virtually insoluble in
the common organic solvents, and reacted with DMSO
and DMF with heat and gas evolution. The yield of the
latter compound was 12–14% of the weight of the residue
after evaportion of the filtrate.
stable only in solution [13]. Therefore in the empirical
formula of the compound (C8H4N2O2)n n ³ 3.At the same
time it should be mentioned that in [13] was described
the oxidation of 2,3-dihydrophthalazine-1,4-dione with
Pb(OAc)4 giving bright-green solution of phthalazine-1,4-
dione which reacted with 1,3-dienes by Diels-Alder type
process. On storage of this solution an amorphous
colorless precipitate separated that contained 16% of
nitrogen, was insoluble in water and common organic
solvents, and decomposed at heating to 190–200°C.
Clement [13] believed that this compound originated from
phthalazinedione polymerization.
The large amount of phthalimide in reaction products
evidences the low reactivity of azoalkenes IIIa, IIIb. It
is in agreement with the result of the GLC analysis of
the reaction mixture obtained from 2-isopropylazopropene
IIIb:According to these data ~70% of the azo compound
remains in the reaction mixture also when all Pb(OAc)4
is added. However it is necessary to state that neither at
oxidation of hydrazide I in the absence of any substrates
[10] nor in the many described examples of its oxidative
addition to olefins, dienes, enynes, styrenes, azo compound
etc. [11, 12] has been observed a formation of compound
like the insoluble substance we have obtained. Hence it
is presumable that the conjugated azoalkene still takes
part in the reaction giving rise to an unstable compound
that at evaporation of its green-yellow solution in CH2Cl2
suffers decomposition and/or oligomerization.
Notwithstanding a certain likeness of the properties
of the latter compound and our products we should take
into account, firstly, that the oxidation of aminophthalimide
I does not yield the phthalazine-1,4-dione, and secondly,
that in the absence of the conjugated azoalkenes we do
not obtain these products. Thus the question of the
character of insoluble compound obtained remains open.
Finally we may state that under the given reaction
conditions and workup procedure we failed to isolate any
products of aminoimide I oxidative addition to a,b-un-
saturated azo compounds IIIa, IIIb, and they apparently
were also lacking in the dry residue after evaporation of
the reaction mixture. In contrast, aminoimide I oxidative
addition to very similar 1-isopropylazocycloalkenes IVa,
IVb resulted in bicyclic 1 isopropylazoaziridines Xa, Xb,
yet in a low yield.
In the IR spectrum of the insoluble substances that
we obtained in both reactions appeared strong absorption
bands corresponding to the stretching vibrations of the
In the similar way this reaction occurs with 1-phenyl-
azocyclohexane, and the properties of adducts Xa, Xb
are like the characteristics of the 1-phenylazo-7-phthal-
imido-7-azabicyclo-[4.1.0]heptane we have described
–1
C=O bonds at ~1750 cm , and also vibration bands of
the aromatic ring. Therefore most probably the phthaloyl
fragment is retained in these molecules. The elemental
analyses of these products may be attributed (although
with a large error) to a formula (C8H4N2O2)n. Then at
n = 1 this empirical formula might correspond to the
structure of phthalazine-1,4-dione, and at n = 2 to
bisphthaloyltetrazene.
1
before [1, 2]. In the H NMR spectra of azoaziridines
Xa, Xb appears a characteristic doublet of the aziridine
proton at ~4 ppm, in the 13C NMR spectrum the two
carbon atoms of the three-membered ring are observed
at ~70–80 (C1) and 50 ppm. A known characteristic
feature of N-aminoaziridine derivative is the high barrier
to aziridine nitrogen inversion [14]. Inasmuch as in the
1H and 13C NMR spectra of both bicyclic aziridines Xa,
Xb as also in the spectra of 1 phenyl-azo-7-phthalimido-
7-azabicyclo[4.1.0]heptane [1, 2] only a single set of
signals is clearly observed they evidently to over 90%
exist in the form of the more stable invertomer with the
syn-position of the aziridine proton and the heterocyclic
fragment.
13L
1 1
3L1 1+
1
,9Dꢀꢁ,9E
3Eꢀ2$Fꢁ
;Dꢀꢁ;E
n = 1 (a), 2 (b).
However the properties of the known bisphthaloyl-
tetrazene [10] are quite different from those of the
products we obtained, and the phthalazinedione-1,4 is
The formation of azoaziridines Xa, Xb may be either
due to the difference in the reactivity of the trisubstituted
bond >C=CH– in compounds IVa, IVb and of the 1,1
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 2 2005

208
KUZNETSOV et al.
disubstituted bond >C=CH2 in azoalkenes IIIa, IIIb or
simply to the greater stability of these products under
conditions of the reaction and workup; however, the
reasons thereof are unclear. It is also interesting that the
oxidative addition of aminoimide I to both 1-isopropyl-
azocycloalkenes IVa, IVb afforded azoaziridines whereas
the only product of this reaction with 1-phenylazocyclo-
pentene was 2-phenyl-2,4,5,6-tetrahydrocyclopenta-
[d][1,2,3]triazole [1, 2]. This fact once more shows the
high sensitivity of the reaction under study to relatively
small changes in the structure of the initial azoalkene.
Allylisopropylamine. To 118 g (2 mol) of isopropyl-
amine was slowly added while cooling with ice-salt
mixture 121 g (1 mol) of allyl bromide. The separated
precipitate was filtered off, the filtrate was subjected to
distillation on a column (12 plates) collecting the fraction
of bp 95–98°C (AllNHPr-i). The precipitate was treated
with 50% KOH solution while distilling off the volatile
products up to bp 100°C, the distillate was dried over
KOH and subjected to column distillation over alkali
collecting the fractions of bp 30–33°C (isopropylamine)
and 96–97°C (AllNHPr-i). The overall yield of
allylisopropylamine was 23.6 g (24%), nD20 1.4158 (publ.:
bp 96–97°C, nD25 1.4140 [16]).
EXPERIMENTAL
Alkylallylnitrosamines VIa, VIb. To a solution of
105 ml of concn. hydrochloric acid (d 1.19 g/cm3) in
200 ml of water while cooling with ice-salt mixture was
slowly added dropwise at stirring 1 mol of alkylallylamine
and then by small portions 105 g (1.5 mol) of NaNO2.
The reaction mixture was heated for 30 min at stirring
on a boiling water bath, and afterwards the upper layer
was separated, dried with MgSO4, and distilled in a
vacuum.
1H NMR spectra of compounds II, III, V–IX were
registered on spectrometers Varian EM-360 (60 MHz)
and HA-100D-15 (100 MHz) from 5–25% solutions in
CDCl3 or CCl4 using HMDS or TMS as internal
1
reference. H and 13C NMR spectra of compounds IV
and X were recorded on spectrometer Varian Gemini-
2000 (200 MHz) from solutions in CDCl3, internal
reference TMS or the solvent signals. Mass spectra of
liquids were obtained on a GC-MS LKB-2091 instrument,
ionizing electrons energy 70 and 12 eV, mass spectra of
solid samples were measured on Hewlett-Packard HP-
5985A installation at direct admission of the sample into
the ion source, ionizing electrons energy 70 eV. IR spectra
were taken on UR-10 spectrometer from samples
prepared as pellets with KBr or as mulls in mineral oil.
Allylmethylnitrosamine (VIa). Yield 82%, bp 79°C
(30 mm Hg), d240 0.9767, nD20 1.4640, MRD 28.29,
calc. 28.00.Amixture of syn-anti-isomers in a ratio ~3:8.
1H NMR spectrum (60 MHz), d, ppm: 2.90 s and 3.70 s
(intensity ratio ~8:3, overall intensity 3H, CH3), 4.15 d
(J 5 Hz) and 4.74 d (J 5 Hz) (intensity ratio ~3:8, overall
intensity 2H, CH2), 5.06–5.50 m (2H, =CH2), 5.64–
6.33 m (1H, =CH). Mass spectrum, m/z (Irel, %): 101 (2),
100 (33) [M]+, 99 (2), 84 (6), 83 (100), 73 (4), 70 (4),
69 (6), 68 (18), 59 (13), 57 (10), 56 (4), 55 (10), 54 (7),
45 (1), 44 (14), 43 (41), 42 (81), 41 (6), 40 (5), 39 (30),
38 (3), 37 (2), 32 (5), 31 (6), 30 (25).
GLC analysis was carried out on a chromatograph
LKhM-8MD, detector katharometer, column 2300 ´
3 mm, stationary phase 5% SE-30 on Inerton-Super 0.16–
0.20, carrier gas helium, flow rate 25–30 ml/min.
Elemental analyses were performed on a CHN-
analyzer Hewlett-Packard HP-185B. The preparative
separation of reaction mixtures was done by column
chromatography on silica gel 40–100 mm. The
composition of reaction mixtures obtained by fractions
separation, and the purity of products isolated were tested
by TLC on Silufol UV-254 plates.
Allylisopropylnitrosamine (VIb).Yield 80%, bp 91–
92°C (20 mm Hg), d240 0.9435, nD20 1.4590, MRD 37.12,
calc. 37.30. A mixture of syn-anti-isomers in a ratio
1
~1:10. H NMR spectrum (60 MHz), d, ppm: 1.13 d
(J 6.5 Hz) and 1.45 d (J 6.5 Hz) (intensity ratio ~1:10,
overall intensity 6H, 2CH3), 4.08 d (CH2 of main isomer,
J 5 Hz), ~4.7 sept (>CH of main isomer, J 6.5 Hz) on the
background of 4.40–5.03 m (CH2 and >CH of minor
isomer, overall intensity 3H), 5.03–6.29 m (3H,
CH=CH2). Mass spectrum, m/z (Irel, %): 129 (4) 128 (37)
[M]+, 113 (2), 112 (2), 111 (19), 98 (8), 97 (1), 96 (2),
87 (5), 86 (11), 84 (1), 83 (12), 82(20), 71 (3), 70 (5),
69 (37), 68 (15), 59 (2), 58 (8), 57 (4), 56 (40), 55 (16),
54 (7), 44 (5), 43 (95), 42 (28), 41 (100), 40 (9), 39 (28),
38 (2), 32 (5), 30 (10); (12 eV): 129 (8), 128 (100) [M]+,
Refraction indices of liquids were measured onAbbe
–4
refractometer IFR-22 with an accuracy to 2´10 and
on Pulfrich refractometer of IRF-23m type with an
–5
accuracy to 2´10 . Densities were measured with the
use of Byron pycnometers of 1–10 ml volume accurate
–4
–5
to 5´10 –5´10 g/cm3.
Conjugated alkylazopropenes III were synthesized by
procedure [6]. N-Aminophthalimide I was obtained as
described in [15].
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 2 2005

OXIDATIVE ADDITION OF N-AMINOPHTHALIMIDE
209
113 (2), 112 (35), 111 (48), 99 (14), 98 (45), 87 (86),
86 (19), 70 (28), 69 (62), 68 (17), 59 (21), 57 (15), 56 (5),
43 (18), 42 (3), 41 (5), 40 (3); m* 96.2 (128 > 111).
Acetaldehyde allylisopropylhydrazone (Vd). To
17 g (0.15 mol) of 1-allyl-1-isopropylhydrazine (VIIb)
was added at stirring while cooling with ice-water mixture
9 g (0.2 mol) of acetaldehyde. The reaction mixture was
heated at 40°C for 1h, the organic layer was separated,
dried over potassium carbonate, and distilled in a vacuum.
Yield 15.4 g (73%), bp 65°C (74 mm Hg), d240 0.8376,
1-Alkyl-1-allylhydrazines VIIa, VIIb (by procedure
[17]). Into a thick-walled tough vessel of 3 liter capacity
equipped with a powerful stirrer was charged 200 ml of
water, 78 g (1.2 mol) of zinc, 10 ml of mercury, and 30 ml
of concn. HCl. At starting the stirrer zinc was covered
with an amalgam, the vessel was cooled with water-ice
mixture, and 400 ml of water and 250 ml of concn. HCl
was added.At cooling and vigorous stirring to the mixture
within 1 h was added dropwise 0.6 mol of nitrosamine
VIa, VIb. The stirring was continued till the end of heat
liberation (~2.5 h), the solution was poured into a flask of
2 liter capacity, a solution of 130 g of NaOH in 130 ml of
water was added, and the mixture was subjected to steam
distillation. The process was carried out till the nD20 of the
distillate coming into the receiver became smaller that
1.3360 (300–400 ml of total distillate). The distillate was
saturated with KOH (~350 g), the organic layer was
separated, dried over KOH, and hydrazines VIIa, VIIb
were distilled in a nitrogen flow.
nD20 1.4552, MRD 45.42, calc. 45.06. H NMR spectrum
1
(60 MHz), d, ppm: 1.10 d (6H, 2CH3, J 6.5 Hz), 1.83 d
(3H, CH3, J 5.2 Hz), ~3.5 sept (CH, J 6.5 Hz) on the
background of a signal 3.13–3.87 m (CH2, overall intensity
3H), 4.99–5.50 m (2H, =CH2), 5.60–6.30 m (1H, =CH),
6.70 q (1H, N=CH, J 5.2 Hz).
Acetone alkylallylhydrazones Vb, Ve. To a cooled
with ice water mixture of 12 g (0.2 mol) of acetone,
0.8 g of calcium chloride, and 10 ml of anhydrous ether
was slowly added at intermittent shaking 0.1 mol of
hydrazine VIIa, VIIb, then the mixture was heated for
1 h at 35–45°C. On cooling the water formed was
separated, the reaction product was dried over potassium
carbonate and distilled in a vacuum.
Acetone allylisopropylhydrazone (Ve). Yield 55%,
bp 72°C (37 mm Hg), d240 0.8216, nD20 1.4447, MRD 49.77,
Allylisopropylhydrazine (VIIb). Yield 40%, bp 70–
72°C (76 mm Hg), d240 0.8351, nD20 1.4448, MRD 36.38,
calc. 36.82. 1H NMR spectrum (60 MHz), d, ppm:
1.00 d (6H, 2CH3, J 6.5 Hz), ~2.7 sept (CH, J 6.5 Hz) on
the background of a wide signal 2.47–3.03 (NH2, CH2,
overall intensity 5H), 4.97–5.50 m (2H, =CH2), 5.67-
6.43 m (1H, =CH). Mass spectrum, m/z (Irel, %): 115 (4),
114 (48) [M]+, 113 (11), 100 (7), 99 (100), 87 (2), 84 (1),
74 (1), 73 (25), 72 (2), 71 (4), 70 (1), 69 (2), 68 (2),
67 (3), 59 (2), 58 (5), 57 (12), 56 (53), 55 (7), 54 (7),
45 (18), 44 (15), 43 (23), 42 (13), 41 (57), 40 (3), 39 (16),
38 (1), 31 (5), 30 (9), 29 (9), 28 (25); m* 86 (114 > 99),
46.8 (114 > 73); (12 eV): 115 (12), 114 (100) [M]+, 100 (5),
99 (71), 87 (1), 74 (1), 73 (25), 56 (2), 43 (2), 41 (1).
1
calc. 49.71. H NMR spectrum (60 MHz), d, ppm:
0.95 d (6H, 2CH3, J 6.5 Hz), 1.88 s (6H, 2CH3),
2.87 sept (1H, CH, J 6.5 Hz), 3.17 d (2H, CH2,
J 6.5 Hz), 4.82–5.23 m (2H, =CH2), 5.43–6.10 m (1H,
=CH).
Isomerization of alkylallylhydrazones V into
g,d-unsaturated azo compounds II [4]. Into an ampule
of 10 ml capacity made of molybdenum glass was
charged 4–6 ml of hydrazone V. Through the fluid nitrogen
or argon was bubbled for 10–15 min, then the ampule
was sealed and heated on an oil bath at 170–185°C for
20–35 h. On cooling the ampule was opened and the
product was distilled.
Formaldehyde alkylallylhydrazones Va, Vc.
To 0.3 mol of 1-alkyl-1-allyl-hydrazine VIIa, VIIb was
slowly added at stirring while cooling with ice 29 ml
(0.3 mol) of 34% formaldehyde water solution. Then at
cooling 20 g of KOH was added, the organic layer was
separated, dried over potassium carbonate, and distilled
in a vacuum.
4-Methylazo-1-butene (IIa). In most runs in 20 h
at 170–175°C the reaction mixture suffered tarring. Its
distillation afforded 15–25% of target reaction product
IIa (bp 90–98°C, nD20 1.4200–1.4330) with an admixture
of up to 25% of the initial hydrazone and a fraction of
sufficiently pure formaldehyde allyl-methylhydrazone
(Va) (bp 118–120°C, nD20 1.4598). The recovery of the
latter (30–40%) varied depending on the heating period.
The repeated isomerization of the recovered hydrazone
occurred as a rule without tarring and afforded sufficiently
pure azo compound IIa in a 20–30% yield, bp 89–92°C,
nD20 1.4196´1.4210 (publ.: bp 87–90°C, nD20 1.4185 [4]).
Formaldehyde allylisopropylhydrazone (Vc). Yield
72%, bp 78°C (105 mm Hg), d240 0.8402, nD20 1.4565,
1
MRD 40.84, calc. 40.41. H NMR spectrum (60 MHz),
d, ppm: 1.11 d (6H, 2CH3, J 6.5 Hz), ~3.5 sept (CH,
J 6.5 Hz) on the background of a signal at 3.30–3.80 m
(CH2, overall intensity 3H), 4.90–5.33 m (2H, =CH2),
5.52–6.20 m (3H, =CH and N=CH2).
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 2 2005

210
KUZNETSOV et al.
4-Methyl-4-methylazo-1-pentene (IIb) was obtain-
residue was subjected to chromatography on a column
charged with 30 g of silica gel (eluent petroleum–ethyl
ether, 5:1). Yield of 1 isopropyl-azocyclopentene (IVa)
1.35 g (49%), yellowish fluid of sharp odor, quickly
ed by heating compound Vb for 30 h at 185°C in a 88%
yield (contained 12% of initial hydrazone Vb), bp 118–
120°C, nD20 1.4298 (publ.: bp 113–115°C, nD20 1.4270 [4]).
1
decomposing at room temperature. H NMR spectrum
4-Isopropylazo-1-butene (IIc) was obtained by
heating hydrazone Vc for 20 h at 180–185°C. Yield 80%,
bp 127–128°C, d420 0.7891, nD20 1.4208, MRD 40.54, calc.
40.08. 1H NMR spectrum (60 MHz), d, ppm: 1.23 d
(6H, 2CH3, J 6.5 Hz), 2.50 q (2H, CH2, J 7 Hz),
3.64 sept (1H, CH, J 6.5 Hz), 3.83 t (2H, CH2N, J 7 Hz),
4.84–5.30 m (2H, =CH2), 5.50–6.24 m (1H, =CH). Mass
spectrum, m/z (Irel, %): 127 (3), 126 (25) [M]+, 111 (4), 85
(2), 84 (2), 83 (6), 70 (3), 69 (4), 57 (3), 56 (25), 55 (94),
54 (5), 53 (7), 51 (1), 44 (4), 43 (100), 42 (8), 41 (43),
40 (4), 39 (21), 38 (13), 32 (9), 30 (1); (12 ýB): 127 (9),
126 (96) [M]+, 112 (1), 111 (15), 85 (3), 84 (6), 83 (21),
70 (9), 69 (11), 57 (9), 56 (63), 55 (100), 54 (7), 44 (14),
43 (58), 42 (3).
(CDCl3), d, ppm: 1.26 d (6H, 2CH3, J 6.6 Hz), 1.97 quint
(2H, H4, J 7.8 Hz), 2.40–2.56 m (4H, H3,5), 3.68 sept
(1H, CH, J ~6.5 Hz), 6.60 t.t (1H, H2, 3J 2.8, 4J 1.6 Hz).
13C NMR spectrum (CDCl3), d, ppm: 20.7 (2CH3), 22.0
(C4), 27.7 (C3), 41.2 (C5), 67.8 (CH), 138.2 (C2), 159.2
(C1).
1-Isopropylazocyclohexene (IVb). To a cooled to
–10°C dispersion of 2.07 g of potassium carbonate in
a mixture of 1.33 g (10 mmol) of 2-chlorcyclohexanone
and 25 ml of dichloromethane was added dropwise at
vigorous stirring a solution of 1.48 g (20 mmol) of
isopropylhydrazine in 15 ml of dichloromethane. The
reaction mixture was additionally stirred for 30 min at
cooling and then it was allowed to warm up to room
temperature. The greenish solution was passed through
a 4 cm bed of silica gel on a glass frit filter, and the silica
gel was washed with dichloromethane. The solvent was
distilled off in a vacuum, the oily residue was subjected
to chromatography on a column charged with 25 g of
silica gel (eluent petroleum ether–ethyl ether, 5:1). Yield
of compound IVb 1.44 g (95%), greenish fluid with a
pleasant sweetish odor, Rf 0.28 (hexane–ethyl ether, 9:1).
1H NMR spectrum (CDCl3), d, ppm: 1.26 d (6H, 2CH3,
J 6.6 Hz), 1.70 m (4H, H4,5), 2.19 m (2H) and 2.65 m
(2H, H3,6), 3.68 sept (1H, CH, J 6.6 Hz), 6.60 t (1H, H2,
J ~5 Hz). 13C NMR spectrum (CDCl3), d, ppm: 20.7
(2CH3), 22.0, 22.3, 22.5 (C3,4,5), 25.7 (C6), 67.3 (CH),
137.6 (C2), 153.7 (C1).
4-Isopropylazo-1-pentene (IId) was obtained by
heating hydrazone Vd for 30 h at 180°C. Yield 60%, bp
140–142°C, d420 0.7862, nD20 1.4214, MRD 45.18, calc.
44.73. 1H NMR spectrum (60 MHz), d, ppm: 1.16 d (9H,
3CH3, J 6.5 Hz), 2.15–2.51 m (2H, CH2), 3.13–3.50 m
(2H, 2CHN), 4.69–5.15 m (2H, =CH2), 5.28–6.01 m (1H,
=CH). Mass spectrum, m/z (Irel, %): 141 (1), 140 (8) [M]+,
125 (1), 99 (1), 97 (1), 84 (1), 83 (1), 71 (3), 70 (9),
69 (53 ), 68 (4), 67 (3), 57 (3), 56 (5), 55 (2), 54 (1),
53 (4), 44 (2), 43 (40), 42 (9), 41 (100), 40 (3), 39 (12);
(12 eV): 141 (2), 140 (18) [M]+, 125 (1), 98 (1), 97 (1),
84 (4), 83 (2), 71 (12), 70 (32), 69 (100), 57 (4), 56 (13),
43 (27 ), 41 (8).
4-Isopropylazo-4-methyl-1-pentene (IIe) was
obtained in a 45% yield.Admixture of hydrazone Ve about
10%, bp 155–158°C, dD20 0.7987, nD20 1.4303, MRD 49.92,
calc. 49.38. 1H NMR spectrum (60 MHz), d, ppm:
1.09 C (6H, 2CH3), 1.25 d (6H, 2CH3, J 6.5 Hz), 2.10 d
(2H, CH2, J 7 Hz), 3.53 sept (1H, CHN, J 6.5 Hz), 4.82–
5.25 m (2H, =CH2), 5.39–6.09 m (1H, =CH).
Oxidative addition of N-aminophthalimide (I) to
azoalkenes II and III. To a cooled to –20°C dispersion
of 1.62 g (10 mmol) of aminoimide I and 4 g (30 mmol)
of fine powder of potassium carbonate in a solution of
10 mmol of azo compound in 50 ml of dichloromethane
was added within 30 min a solution of 4.43 g (10 mmol)
of Pb(OAc)4 in a minimum volume of dichloromethane
(~50 ml). The reaction mixture was stirred for 1 h and
then the cold reaction mixture was filtered through 10 g
of silica gel (40–100 mm). The precipitate was washed
with cold dichloromethane till colorless filtrate (~50 ml).
The solution obtained was evaporated in a vacuum to
dryness.
1-Isopropylazocyclopentene (IVa). To a cooled to
–20°C dispersion of 3.55 g of sodium sulfate in a mixture
of 25 ml of ethyl ether and 2.37 g (20 mmol) of 2-chloro-
cyclopentanone was added dropwise at vigorous stirring
a solution of 2.96 g (40 mmol) of isopropyl-hydrazine in
10 ml of ethyl ether. The reaction mixture was additionally
stirred for 30 min at –20°C and then it was allowed to
slowly warm up to room temperature. The yellowish
solution was passed through a 4 cm bed of silica gel on a
glass frit filter and the silica gel was washed with ethyl
ether. The solvent was distilled off in a vacuum, the oily
In reactions with g,d-unsaturated azo compounds IIa–
IIe the residue after solvent evaporation was subjected
to chromatography on a column charged with 25–30 g
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 2 2005

OXIDATIVE ADDITION OF N-AMINOPHTHALIMIDE
211
of silica gel (40–100 mm) eluting with a mixture benzene–
ethyl acetate, 7:1, and collecting the fractions of Rf 0.5–
0.3 (yellow) and 0.25–0.15 (colorless). On evaporating
the solvent in a vacuum we obtained from the first fraction
a yellow oily substance that slowly crystallized on standing
(sometimes within 2–3 days). According to the 1H NMR
spectra this fraction usually contained a mixture of two
regioisomeric phthalimidoazimines. From the second
fraction in all cases was isolated only phthalimide.
0.35–0.47 (benzene–ethyl acetate, 7:1). The reaction
product partially crystallized at storage, the crystalline
compound was separated and washed with a little ether.
1
The weight of crystals was 319 mg. H NMR spectrum
(60 MHz), d, ppm: 1.10–1.53 m (5H), 2.10–2.51 m (4H),
2.66–2.83 m (2H), 7.74–8.00 m (5H) (the intensity values
of signals were approximated to the nearest integer).
Found, %: C 68.7; H 5.8; N 11.7. (C7H7NO)n. Calculated,
%: C 69.4; H 5.8; N 11.6. On evaporating the filtrate 560
mg of yellow oily substance was isolated that gradually
solidified at cooling furnishing a low-melting (mp 45–
47.5°C) compound composed of a mixture of (buten-3-
yl)isopropyl-3-phthalimidoazimines (VIIIb) and
(IXb) in a ratio ~1:2.5. The product obtained was
reprecipitated from 2 ml of ether by adding 1 ml of pentene
to isolate 120 mg of fine crystals of mp 45–47°C. Yield
of the pure azimine mixture in two runs was 22 and
From 0.38 g (3.9 mmol) of 4-methylazo-1-butene (IIa)
and 0.63 g (3.8 mmol) of imide I after oxidation with 1.8
g (4.7 mmol) of Pb(OAc)4 with added 1.5 g of potassium
carbonate we obtained 0.965 g of dry residue of the
reaction mixture.As a result of its separation on a column
charged with 10 g of silica gel we isolated 205 mg (38%)
of phthalimide of Rf 0.21–0.25 and 512 mg (49%) of a
~1.5:1 mixture of 1-(buten-3-yl)-2-methyl-3-
phthalimidoazimine (VIIIa) and 2-(buten-3-yl)-1-
methyl-3-phthalimidoazimine (IXa) of Rf 0.42–0.54,
mp 79–81.5°C. 1H NMR spectrum (100 MHz, CDCl3),
d, ppm: 2.60 m (2H, CH2C=), 3.47 s (N1CH3), 3.67 t
(N1CH2, J 7 Hz), 3.91 s (N2CH3), 4.15 t (N2CH2,
J 7 Hz), overall intensity of the latter four signals equals
to 5H, intensity ratio in the pairs of singlets at 3.91 and
3.47 ppm and triplets at 3.67 and 4.15 ppm ~1.5:1; 4.90–
5.30 m (2H, =CH2), 5.45–6.08 m (1H, =CH), 7.70–
7.94 m (4H, PiN). 13C NMR spectrum (Varian CFT-20
instrument, 20 MHz, CDCl3), d, ppm: 32.3 (CH2C=, both
isomers), 42.8 (N1CH3), 49.9 (N2CH3), 54.7 (N1CH2),
60.7 (N2CH2), 116.1 and 118.1 (=CH2), 123.7 and 124.5
(PiN, C3,6), 130.8 and 132.9 (PiN, C1,2), 133.9 and 134.6
(PiN, C4,5), 135.2 and 136.4 (=CH), 166.0 and 166.4
1
28%. H NMR spectrum (100 MHz), d, ppm: 1.30 d
(J 6.5 Hz), 1.38 d (J 6.5 Hz) (intensity ratio ~2.5:1, overall
intensity 6H, 2CH3), 2.60 m (2H, CH2), 3.68 t (N1CH2,
J 7 Hz) and 4.08 t (N2CH2, J 7 Hz) (intensity ratio ~1:2.5,
the downfield triplet is the stronger one; overall intensity
2H), 4.34 sept (N1CH, J 6.5 Hz) and 4.74 sept (N2CH,
J 6.5 Hz, overall intensity 1H), 4.90–5.32 m (2H, =CH2),
5.51–6.15 m (1H, =CH), 7.71–7.95 m (4H, PiN). Found,
%: C 62.4; H 6.2; N 19.4. C15H18N4O2. Calculated, %:
C 62.9; H 6.3; N 19.6.
In reaction of 1.52 g (10.8 mmol) of 4-isopropylazo-
1-pentene (IId) with 1.59 g (9.8 mmol) of aminoimide I
according to TLC data at least two products were obtained
characterized by close values of Rf (0.50 and 0.45 in the
system benzene–ethyl acetate, 7:1). We succeeded in
their separation, although with great losses. The product
of Rf 0.50 was a mixture of similar amounts of azimine
regioisomers VIIIc and IXc, the former compound,
(1Z,2E)-2-isopropyl-1-(1-methyl-buten-3-yl)-3-
phthalimidoazimine (VIIIc), slightly prevailing.
1H NMR spectrum (100 MHz), d, ppm: 1.24–1.45 m (9H,
3CH3), 2.20–2.80 m (2H, CH2C), 4.28–4.92 m (2H,
CHN2,3), 4.96–5.30 m (2H, =CH2), 5.40–6.18 m (1H,
=CH), 7.68–7.96 m (4H, PiN). Found, %: C 63.2; H 6.5;
N 17.9. C16H20N4O2. Calculated, %: C 64.0; H 6.7;
N 18.6. Compound of Rf 0.45 had the 1H NMR spectrum
identical to that of the substance of the assumed empirical
formula (C7H7NO)n isolated in the experiment involving
4-isopropylazo-1-butene (IIc), mp 92–98°C (decomp.).
–1
(C=O). IR spectrum, n, cm : 3090 v.w, 3039 v.w, 3018
v.w, 2940 v.w, 2880 v.w 1783 m, narrow, 1725 v.s, broad;
1650 w, 1613 w, 1498 s, 1450 m. Found, %: C 60.2;
H 5.2; N 20.6. C13H14N4O2. Calculated, %: C 60.5;
H 5.5; N 21.7.
In the experiment with 5 mmol of 4-methylazo-4-
methyl-1-pentene (IIb) (the azo compound contained an
impurity of the initial hydrazone) we failed to obtain
adducts with the azo compound. The chromatographic
separation of the reaction mixture yielded phthalimide
(~70%) and 80 mg of unidentified substance of Rf 0.60–
0.48 (benzene–ethyl acetate, 7:1) with the following
1H NMR spectrum (60 MHz), d, ppm: 1.10 s (6H),
1.45 s (3H), 2.01 s (2H), 2.30–2.38 distorted d (?) (2H,
J ~7 Hz), 4.90–6.30 m (3H), 7.80–8.00 m (3H).
In the experiment with 15 mmol of 4-isopropylazo-4-
methyl-1-pentene (IIe) we failed to isolate any adducts
with the azoalkene, and only 56% of phthalimide was
obtained.
From 1.29 g (10 mmol) of 4-isopropylazo-1-butene
(IIc) we obtained 1.23 g of yellow oily substance of Rf
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 2 2005

212
KUZNETSOV et al.
Reaction with conjugated azoalkenes IIIa, IIIb.
dichloromethane was continued till colorless filtrate.
The solvent was distilled off under reduced pressure of
a water-jet pump, and the residue was subjected to further
workup.
Along the general procedure from 1.67 g (10.3 mmol) of
aminoimide I and 0.89 g (10.6 mmol) of 2 methylazo-1-
propene (IIIa) we obtained 1.72 g of dry residue
containing according to TLC data (benzene–ethyl acetate,
7:1) two substances characterized by Rf 0.38 and 0.21.
A portion of this residue (0.23 g) was extracted with
15 ml of chloroform (5´3 ml). From the extract after
evaporation and recrystallization from ethanol we
obtained 0.175 g (76%) of phthalimide (Rf 0.21, mp 228–
233°C, no melting point depression in the mixture with
an authentic sample). The residue insoluble in CHCl3
(32 mg, 14%) was a colorless powdery substance that
completely decomposed at heating to ~150°C, reacted
with dimethyl sullfoxide and dimethylformamide with
self-heating and gas evolution, and was not notably soluble
in any of the common organic solvents. IR spectrum, n,
Reaction with 1-isopropylazo-1-cyclopentene
(IVa). The oily residue (846 mg) was ground with 50 ml
of pentane, the precipitate was filtered off (phthalimide,
324 mg). The filtrate was evaporated, the residue was
applied on 30 g of silica gel, gradual elution with pentane–
ether, from 5:1 to 1:1. We obtained 7 mg of the initial azo
compound and 158 mg (11%) of 1 isopropylazo-6-
phthalimido-6-azabicyclo-[3.1.0]hexane (Xa).
1
Yellowish oily substance, Rf 0.59 (ethyl ether). H NMR
spectrum, d, ppm: 1.11 d (J 6.3 Hz) and 1.13 d (J 5.6 Hz)
(6H, 2CH3), 1.57–1.78 m (2H, H3), 1.90–2.04 m (1H),
2.10–2.18 m (1H), 2.27–2.40 m (2H), 3.60 sept (1H,
i-Pr, CH, J 6.5 Hz), 4.19 d (1H, H5, J 2.8 Hz), 7.61–
7.73 m (4H, PiN). 13C NMR spectrum, d, ppm:
19.86 (C3), 19.90 and 19.98 (2CH3), 26.3 and 27.3 (C2,4),
54.9 (C5), 68.1 (i-Pr, CH), 81.0 (C1), 122.7 (PiN, C3,6),
130.6 (PiN, C1,2), 133.7 (PiN, C4,5), 165.0 (C=O).
–1
cm : 3308 v.w, 3269 w, 3110 v.w, 3070 v.w, 2927 v.w,
2863 v.w, 1793 m, 1750 and 1730 v.s, 1613 w, 1475 m.
Found, %: C 58.2; H 3.1; N 16.6. (C8H4N2O2)n.
Calculated, %: C 60.0; H 2.52; N 17.5.
The oxidation of 1.60 g (9.9 mmol) of aminoimide I in
the presence of 1.18 g (10.3 mmol) of 2 isopropylazo-1-
propene (IIIb) gave similar results. GLC analysis of the
reaction mixture by the method of internal reference
(isooctane) showed that after addition of the total amount
of Pb(OAc)4 the mixture contained ~70% of initial azo
compound IIIb. The dry residue after evaporation of the
reaction mixture contained according to TLC data
(benzene–ethyl acetate, 7:1) two substances char-
acterized by Rf 0.44 and 0.20. Applying the procedure
described above from the residue were isolated phthal-
imide (71%) and 13% (by weight) of insoluble residue
possessing the same characteristics as the unidentified
The last fractions contained 88 mg of phthalimide
[overall amount 412 mg (56%)].
Reaction with 1-isopropylazo-1-cyclohexene
(IVb). The oily residue (1.01 g) was subjected to
chromatography on a column packed with 55 g of silica
gel, gradual elution with pentane–ether, from 9:1 to 5:1.
We obtained 130 mg (17%) of the initial azo compound
and 498 mg (32, 38% taking into consideration the
unreacted azo compound) of 1-isopropyl-azo-7-
phthalimido-7-azabicyclo[4.1.0]heptane (Xb).
Greenish glassy crystalline compound, mp 92–95°C.
1H NMR spectrum, d, ppm: 1.10 d and 1.11 d (6H, 2CH3,
J 6.6 Hz), 1.29–1.39 m and 1.46–1.62 m (4H, H3,4), 2.01–
2.09 m (2H), 2.38 m (1H), 2.65 m (1H), 3.59 sept (1H,
i- Pr, CH, J 6.6 Hz), 3.71 d (1H, H6, J 4.6 Hz), 7.61–
7.72 m (4H, PiN). 13C NMR spectrum, d, ppm: 19.9 and
20.0 (2CH3), 20.2 (C3,4), 23.2 and 23.3 (C2,5), 49.1 (C6),
67.7 (i-Pr, CH), 71.2 (C1), 122.5 (PiN, C3,6), 130.7 (PiN,
C1,2), 133.5 (PiN, C4,5), 164.9 (PiN, C=O). Found, %:
C 65.39; H 6.36; N 17.85. C17H20N4O2. Calculated, %:
C 65.37; H 6.45; N 17.94.
–1
product from the previous run. IR spectrum, n, cm :
3103 v.w, 3070 v.w, 3040 v.w, 2930 v.w, 2860 v.w,
1795 m, 1745 v.s, 1615 w, 1473 m. Found, % : C 57.5;
H 2.7; N 16.4. (C8H4N2O2)n. Calculated, %: C 60.0;
H 2.52; N 17.5.
Oxidative addition of N-aminophthalimide (I) to
1-isopropylazocycloalkenes IV. To a dispersion of 4.83
g (35 mmol) of potassium carbonate in 50 ml of anhydrous
dichloromethane containing 5 mmol of azo compound was
added within 30 min while stirring at cooling to –20´–
30°C in small portions by turns 810 mg (5 mmol) of
aminoimide I and 2.60 g (5 mmol) of lead tetraacetate
containing 15% of acetic acid. The reaction mixture was
stirred for 20 min at the same temperature and then it
was allowed to warm to 12–16°C, was filtered through a
silica gel bed 1.5–2 cm thick. Washing with
The last fractions contained 119 mg (16%) of
phthalimide.
REFERENCES
1. Kuznetsov, M.A., Kuznetsova, L.M., and Shantl’, I.G., Zh.
Org. Khim., 2000, vol. 36, p. 869.
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 2 2005

OXIDATIVE ADDITION OF N-AMINOPHTHALIMIDE
213
2. Kuznetsov, M.A., Kuznetsova, L.M., and Schantl, J.G., Eur.
J. Org. Chem., 2001, vol. 7, p. 1309.
3. Kuznetsov, M.A., Belov, V.N., and Suvorov,A.A.,Abstracts
of Papers, III Vsesoyuznaya konferentsiya po khimii
karbenov (3rd All-Union Conf. on Chemistry of Carbenes),
Moscow: Nauka, 1982, p. 40.
4. Isidorov, V.A., Ioffe, B.V., and Zenkevich, I.G., Dokl. Akad.
Nauk SSM, 1976, vol. 230, p. 605; Isidorov, V.A.,
Moloshnikov, V.A., and Zenkevich, I.G., Zh. Org. Khim.,
1978, vol. 14, p. 1832.
5. Zenkevich, I.G., Isidorov, V.A., and Ioffe, B.V., Zh. Org.
Khim., 1986, vol. 22, p. 1797.
6. Matveeva, Z.M., Kochetov, A.P., Sergeeva, Z.I., Zele-
nin, K.N., and Ioffe, B.V., Zh. Org. Khim., 1969, vol. 5,
p. 424.
7. Suvorov, A.A., Malov, M.Yu., and Kuznetsov, M.A.,
Zh. Org. Khim., 1987, vol. 23, p. 1962.
Helv. Chim. Acta, 1977, vol. 60, p. 816; Leuenberg, C.,
Hoesch, L., and Dreiding, A.S., Helv. Chim. Acta, 1981,
vol. 64, p. 1219.
9. Atkinson, R.S. and Kelly, B.J., J. Chem. Soc., Perkin Trans.
I, 1989, p. 1627.
10. Hoesch, L. and Dreiding, A.S., Helv. Chim. Acta, 1975,
vol. 58, p. 980.
11. Suvorov, A.A. and Kuznetsov, M.A., Usp. Khim., 1987,
vol. 56, p. 1324.
12. Kuznetsov, M.A. and Ioffe, B.V., Usp. Khim., 1989, vol. 58,
p. 1271.
13. Clement, R.A., J. Org. Chem., 1960, vol. 25, p. 1724.
14. Atkinson, R.S. and Malpass, J.R., J. Chem. Soc., Perkin
Trans. I, 1977, p. 2242.
15. Drew, N.D.K. and Hatt, N.H., J. Chem. Soc., 1937, p. 16.
16. D’Amico, J.J., Harman, M.W., and Cooper, R.H., J. Am.
Chem. Soc., 1957, vol. 79, p. 5270.
8. Hoesch, L., Karpf, M., Dunkelblum, E., and Dreiding,A.S.,
17. Ioffe, B.V., Zh. Obshch. Khim., 1958, vol. 28, p. 1296.
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 2 2005