Chemistry of diazocarbonyl compounds: XXVII. Thermolysis and photolysis of diazirines, derivatives of 1,3-dioxane-4,6-dione

Article abstract of DOI:10.1134/S1070428006080197

Photolysis of diazirines, 1,3-dioxane-4,6-dione derivatives, occurs in the presence of methanol or dimethyl sulfide as carbene traps without a formation of carbene intermediates. It was established for the first time that the thermolysis and photolysis of diazirines from the 1,3-dioxane-4,6-dione series led mainly to Wolff rearrangement with a subsequent formation of 5-oxo-1,3-dioxolane-4-carboxylic acids or their derivatives. The data obtained show that the α-oxodiazirines are the key intermediates in the photolysis and Wolff rearrangement of α-diazocarbonyl compounds. Nauka/Interperiodica 2006.

Full text of DOI:10.1134/S1070428006080197

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2006, Vol. 42, No. 8, pp. 1213-1219. Ó Pleiades Publishing, Inc. 2006.
Original Russian Text Ó V.V. Shevchenko, N.N. Khimich, M.S. Platz, V.A. Nikolaev, 2006, published in Zhurnal Organicheskoi Khimii, 2006, Vol.
4
2, No. 8, pp. 1232-1238.
Chemistry of Diazocarbonyl Compounds: XXVII.*
Thermolysis and Photolysis of Diazirines, Derivatives
of 1,3-Dioxane-4,6-dione
a
a
b
a
V.V. Shevchenko , N.N. Khimich , M.S. Platz , and V.A. Nikolaev
a
St. Petersburg State University, St. Petersburg, 198504 Russia
e-mail: vnikola@VN6646.spb.edu
Ohio State University, 120 West 18th Avenue, Columbus, Ohio, 43210 USA
b
Received July 15, 2005
Abstract—Photolysis of diazirines, 1,3-dioxane-4,6-dione derivatives, occurs in the presence of methanol or
dimethyl sulfide as carbene traps without a formation of carbene intermediates. It was established for the first time
that the thermolysis and photolysis of diazirines from the 1,3-dioxane-4,6-dione series led mainly to Wolff
rearrangement with a subsequent formation of 5-oxo-1,3-dioxolane-4-carboxylic acids or their derivatives. The
data obtained show that the a-oxodiazirines are the key intermediates in the photolysis and Wolff rearrangement
of a-diazocarbonyl compounds.
DOI: 10.1134/S1070428006080197
1
Diazirines with alkyl and aryl substituents attached to
and IIb having singlet signals in the H NMR spectra
the carbon atom of the three-membered heterocycle are
as a rule far more stable and less hazardous for application
that their linear isomers, aliphatic diazo compounds. The
diazirines are widely used in the carbene chemistry, and
their transformations are well documented [2]. However
the a-oxodiazirines containing in their structure 3-acil or
which facilitated the identification of the reaction products.
2
2
KY
ꢀꢁꢂꢃQP
2
2
2
2
0
H
0H
5
1
1
!
1
5
2
2
,Dꢀꢁ,,E
,Dꢀꢁ,E
3
-alkoxycarbonyl groups are virtually unstudied and are
,
seldom used in the “carbene “ reactions presumably
because of their unavailability and instability already
mentioned by Schmitz et al. [3] who have first synthesized
the cyclic analogs of the aliphatic diazo compounds.
2
2
2
0
H
'ꢄꢃKY
"
ꢂ
ꢂ
5
In the course of studies of the photochemical trans-
formations of 5-diazo-2,2-dialkyl-1,3-dioxa-4,6-diones I
we [1, 4] and other researchers [5, 6] identified in the
reaction mixture relatively stable cyclic isomers of the
initial diazo compounds, a,a-dioxodiazirines II, and an
efficient photochemical method for preparation of these
compounds was developed [4]. We report here on the
results of studies of the chemical properties of a,a-dioxo-
diazirines II from the 1,3-dioxane series, on establishing
the main routes of their thermolysis and photolysis, and
on the prospects to apply diazirines II as a source of
cyclic a,a-dioxocarbenes III.
2
,
,,Dꢀꢁ,,,E
R = Me (a), t-Bu (b).
Dioxodiazirines IIa and IIb were prepared by the
photochemical isomerization of the corresponding
diazodioxanediones Ia and Ib in a solution THF–NuH
(
NuH = H O, MeOH), 20:1, using irradiation with long-
2
wave UV light (l > 310 nm). The highest yield (40–43%)
was obtained by irradiation of diazo compounds I in the
mixture THF–MeOH [1, 4] (see EXPERIMENTAL).
The procedure we developed for of the photolysis and
the subsequent separation of the reaction products enabled
us within several hours to obtain from diazo compounds I
We chose as the objects of investigation 2,2-dimethyl-
and 2-methyl-2-tert-butyl-substituted dioxodiazirines IIa
1
–2 g of diazirines II. Before use in the photochemical
*
For communication XXVI, see [1].
reactions diazirines II were subjected to thorough
1213

1214
SHEVCHENKO et al.
Table 1. Thermolysis of diazirines IIaand IIb in CDCl and C D
solutions
transition), whereas the short-wave band corresponded
to the p-p* transition [9].
3
6
6
7
KHUPRO\VLVꢀ
The irradiation of diazirines IIa and IIb was performed
with the use of a mercury lamp of a medium pressure
passing its total light thorough a quartz filter (l > 210 nm)
with no additional monochromatization. The reaction
products were identified in the solution analyzed by
'
LD]LULQHꢀ,,ꢁꢀ
VROYHQWꢀꢀ
W ꢁꢀKꢀꢀ
ꢅꢆꢄƒ&ꢇꢀꢀ
Nuꢃꢄ ꢁꢀV
SURGXFWVꢁꢀꢂꢀꢀ
,
ꢀ
,9ꢁꢀ9ꢀ
ꢈꢄꢀ
ꢈꢍꢀ
ꢊꢍ ꢀ
ꢋꢋꢀ
,
,
,
,
,Dꢁꢀ&'&O ±0H2+ꢀ
,Eꢁꢀ&'&O ±+ 2ꢀ
,Dꢁꢀ& ' ±0H2+ꢀ
,Eꢁꢀ& ' ±0H2+ꢀ
ꢈꢉꢊꢀ
ꢆꢉꢋꢀ
ꢈꢉꢍꢀ
ꢈꢉꢃꢀ
ꢌꢉꢆꢀ
ꢈꢉꢄꢀ
ꢃꢉꢌꢀ
ꢈꢊ ꢀ
ꢌꢈ ꢀ
ꢎꢎ ꢀ
ꢌꢈꢀ
1
H NMR spectra of individual compounds which had been
ꢃꢆꢉꢌꢀ
prepared and completely characterized in the course of
the photolysis studies on diazo compounds I [1, 4]. In the
kinetic experiments we performed a qualitative and
quantitative analysis of the reaction mixture by means of
a
ꢀ
Initial diazirine is also present in the reaction mixture (IIa 13%, IIb
8%).
According to the H NMR data, at diazirine IIa conversion ~15%.
1
b
1
1
H NMR spectroscopy without the preparative separation
purification by recrystallization and an additional sublima-
tion in a vacuum. Inasmuch as the diazirines are relatively
prone to isomerization into the corresponding diazo
compounds [7], a,a-dioxodiazirines II were used in
subsequent reactions either just after preparation and
purifying or after short storage at –10...–15°C.
UV spectra of diazirines IIa and IIb considerably differ
from spectral characteristics of diazo compounds I [1, 4,
]. Two weak absorption bands appear in the spectra in
the regions 245–250 and 285–290 nm as shoulders on
the tail of a more short-wave strong absorption band
l < 230–240 nm). The long-wave absorption of diazirines
was previously assigned to the s-p*, p-p*, or p-p*
transition [3], and the latter was believed to be the most
probable [8]. The weak long-wave absorption band was
later shown by quantum-chemical calculations to
correspond more likely to the transition of an electron
from the unshared pair of the nitrogen to the p*
antibonding orbital of the three-membered ring (p-p*
of the mixture.
Thermolysis of diazirine IIa and IIb. Pure crystal-
line dioxodiazirines IIa and IIb can be stored without
notable decomposition or isomerization for many days.
However in solutions the isomerization proceeds much
faster, and therefore prior to studying the photochemical
reactions of dioxodiazirines IIa and IIb we tested their
thermal stability and measured the lifetime of these diazo
substrates. The thermolysis of diazirines was carried out
directly in the probe of the NMR spectrometer at 50 ±
6
1
°C charging into the NMR tube solutions in CDCl or
(
3
C D with nucleophile added [MeOH–(IIa and IIb), 10:1]
6 6
and registering the changes in the amounts of the
components of the reaction mixture at regular time
intervals. From the results of the kinetic experiments we
calculated the half-life of diazirines IIa and IIb (t , 50°C)
1/2
[10].
The data presented in Table 1 show that the half-life
Sryh‡v‰rꢁ
p‚pr‡ꢂh‡v‚
of diazirines IIa and IIb in solution of CDCl and C D
at 50°C amounts to 3.5–4.0 h.
3
6
6
2
ꢀ
ꢀ
2
2
0
H
'
ꢀꢁꢂꢃ &
,,Dꢀꢁ,,E
,Dꢀꢁ,E
&
'&O ꢁRUꢁ& '
5
'ꢀ
&
2 +ꢄ0Hꢅ
,9ꢀꢁ9Dꢀꢁ9E
%ꢀ
Inasmush as the photholysis experiments were carried
out at lower temperature (18–20°C) and for a shorter
time (1–1.5 h) we assumed that the probable thermal
transformations of diazirines IIa and IIb in the course of
the photochemical experiments were negligible.
#
ꢀ
!
ꢀ
By these experiments we also established that the
ꢀ
thermolysis of diazirines II in CDCl at 50°C led to the
3
ꢀ
ꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁ ꢀꢀꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁ!ꢀꢀꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁ"ꢀꢀꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁꢁ#ꢀꢀ
W
ꢃꢁ€v
formation of dioxolanonecarboxylic acid derivatives IV
and V and diazo compounds I in approximately equal
amounts.At the same time in C D solution at the similar
Fig. 1. Thermolysis of diazirine IIb in C D –MeOHsolution at
0°C.
6
6
5
6
6
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 42 No. 8 2006

CHEMISTRY OF DIAZOCARBONYL COMPOUNDS: XXVII.
1215
temperature Wolff rearrangement into V dominated (66–
8%), whereas the isomerization of diazirines II into the
corresponding diazodioxanes I occurred under these
Table 2. Photolysis of diazirines IIa and IIb
7
&
RPSGꢃꢀ
QRꢃꢀ
3KRWRO\VLVꢀSURGXFWVꢁꢀꢂꢀꢀ
9ꢀ 9,ꢀ 9,, ꢀ
±ꢀ ꢆꢇꢀ ±ꢀ ±ꢀ
5HDFWLRQꢀFRQGLWLRQVꢀ
ꢄꢅꢀPLQꢁꢀ0H2+ꢀ
,
ꢀ
conditions to a lesser extent (22–34%) (Fig. 1).
,
,
, ꢀ
Photolysis of diazirines IIa and IIb was carried
, ꢁꢀ,,Eꢀꢈꢅ±ꢄꢅꢀPLQꢁꢀ7+)±0H2+ꢀꢉ±ꢊ ꢀꢄꢆ±ꢆꢋꢀWUDFHV ꢀ ±ꢀ
out in methanol solution or in a mixture of THF (Me S)
2
ꢋꢅ±ꢋꢈꢀPLQꢁꢀ0H 6±
H2+ꢀ
±ꢀ
with methanol at the molar ratio diazirine II : methanol
,, ꢀ
ꢇ±ꢄꢀꢌꢆ±ꢈꢊ
ꢉꢌ±ꢉꢇꢀ
0
1
:10. In the preparative runs the reaction mixture after
,
, ꢁꢀ,,Eꢀꢊ±ꢌꢀKꢁꢀ52+ ±3K &2ꢀ
±ꢀ
±ꢀ ꢆꢍ±ꢆꢋꢀ ±ꢀ
the photolysis was subjected to chromatography on silica
gel, the isolated substances were characterized by spectral
methods under the same conditions as described for the
study of diazo compounds reactions [1, 4].
a
ꢀ
1
According to IR, H NMR spectroscopy and TLC.
b
R = Me for IIa, i-Pr for IIb.
worse as shown by the yield of sulfonium ylide VIIa at
Oꢀ!ꢀꢁꢂꢃꢀQP
the completion of the photolysis (14–16%).
,
,
,Dꢀꢀꢄꢀꢀ9Dꢁꢀ9E
Triplet-sensitized photolysis of diazirines IIa and IIb
in methanol or 2-propanol in the presence of benzo-
phenone resulted in an exclusive formation of dioxane-
diones VIa and VIb (93–97%) (Table 2).
2
2
2
2
2
2
0H
0H
0
H
0H
0H
6
5
The investigation of diazirine II transformations on
heating showed that the main thermolysis path at 50°C in
CDCl and C D solution consisted in nitrogen elimina-
2
2
3
6
6
The kinetic experiments were carried out by sampling
from the photochemical reaction at regular intervals,
evaporating the solvent from the sample in a vacuum
1–2 mm Hg), the residue was mixed with a required
quantity of an internal reference, the mixture was dissolved
in CDCl and immediately analyzed by H NMR
spectroscopy. The principle findings of this part of the
research are given on the scheme and in Table 2.
tion and Wolff rearrangement with the formation of
-oxoacids IV or their methyl esters V, and also in the
5
isomerization into diazo compound I (the ratio of these
(
processes was ~1:1 in CDCl solution and ~2.5:1 in C D ).
3
6 6
Taking into consideration that diazodioxanediones I under
1
3
similar conditions (50°C, solution in CDCl or C D ) are
3
6
6
quite stable and even at heating for 10 h at 80°C remain
virtually intact, we can unambiguously conclude that they
are not intermediates on the route from diazirines II to
Wolff rearrangement products IV and V, and therefore
the latter form in the course of the thermolysis directly
As seen from the data, the photolysis of diazirines II
under the short-wave light (l > 210 nm) in pure MeOH
IIa) or in a mixture THF–MeOH (IIa and IIb) led to
(
the almost exclusive formation of Wolff rearrngement
products Va and Vb (Fig. 2). In the reaction products
obtained in the THF–MeOH mixture we succeeded only
to detect traces of diazodioxanediones I and dioxane-
diones VI as impurities.According to the IR spectroscopy
used as analytical tool during the irradiation of diazirine
IIa in the mixture THF–MeOH, the maximum amount
of diazo compound Ia in the photolysate did not exceed
5
HODWLYHꢆ
FRQFHQWUDWLRQ
ꢀꢁꢁ
ꢂꢁ
ꢃꢁ
ꢄꢁ
ꢅꢁ
ꢁ
1
–2%. The formation of 1,3-dioxane-4,6-dione VIa was
1
qualitatively established by means of H NMR spectro-
scopy and TLC on completion of the photolysis of diazirine
IIa under the same conditions.
Photolysis of diazirine IIa in a mixture Me S–MeOH
2
ꢁ
ꢆꢆꢆꢆꢆꢆꢆꢆꢆꢆꢆꢆꢅꢁꢆꢆꢆꢆꢆꢆꢆꢆꢆꢆꢆꢆꢄꢁꢆꢆꢆꢆꢆꢆꢆꢆꢆꢆꢆꢃꢁꢆꢆꢆꢆꢆꢆꢆꢆꢆꢆꢆꢂꢁ
gave rise to the same set of the reaction products
W
ꢇꢆPLQ
(
Table 2) that had been found at the photochemical
decomposition of diazo compound Ia [1, 4], and the
Fig. 2. Irradiation of diazirine IIb in THF–MeOH solution (l ³
efficiency of the carbene processes is here somewhat
210 nm).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 42 No. 8 2006

1216
SHEVCHENKO et al.
from diazirines II omitting a preliminary isomerization
stage into diazo compounds I. Besides the lack in the
reaction products after thermolysis of diazirines II of
substances originating from dioxocarbenes III insertion
into the O–H bond of methanol and of dioxanediones VI
which is characteristic of carbenes III [1, 4] indicates
that the latter also are not intermediates in this process.
absence of diazodioxanediones I or their characterisic
phototransformation products, dioxanediones VI, which
appear in small amount in the reaction products only when
the photolysis of diazirines II is carried out in the presence
of THF or dimethyl sulfide.
The formation of photoreduction products VI and
S-ylides VII detected when the photolysis of diazirines
Thus we for the first time experimentally have
established the direct thermal transformation of a,a-di-
oxodiazirines II into Wolff rearrangement products,
II was carried out in THF–MeOH or Me S–MeOH
2
solutions may be formally ascribed either to the
photochemical decomposition of diazirines II proper or
to the same process occurring with their isomerization
products, diazo compounds I. It is not possible to make
an unambiguous choice among these opportunities basing
on the experimental data obtained. However we presume
that during the photolysis of diazirines II ylides VII and
dioxanediones VI are generated by carbene
decomposition of diazo compounds I that arise by partial
isomerization of initial diazirines II in the course of the
photochemical reaction [7].
2
-oxoacids IV or their esters V, and these data are not
consistent with the current concepts of this well studied
reaction. The common scheme of Wolff rearrangement
implies that the a-diazocarbonyl compounds convert into
ketenes by a ketocarbene (a) or concerted (b) route [11].
The present study demonstrated that in the thermolysis
of dioxodiazirines II Wolff rearrangement products
formed directly from diazirines II, namely, not involving
diazodioxanediones I and intermediate carbenes III.
Therefore we are able to conclude, that here we are
dealing with a new, “diazirine” Wolff rearrangement
represented below.
The main products of the triplet-sensitized photolysis
of diazirines II are dioxanediones VI apparently
originating from the photolysis of the primary products
of insertion into OH of singlet carbenes (I-s), 5-methoxy-
dioxanediones [1, 12], or from the appearance in the
reaction mixture of triplet carbenes [13]. The latter, as in
the reactions of the corresponding a-diazocarbonyl
compounds (IIIa and IIIb) attack the solvent (alcohol)
giving dioxanediones VI.
ꢀ
2
2
2
2
2
2
0
H
0H
5
KY
D
1
,
1
5
2
2
,,,ꢁV
E
F
1
Thus the direct photolysis of a,a-dioxodiazirines II
from the 1,3-dioxane series occurred without an inter-
mediate formation of the corresponding carbenes, and
these compounds cannot serve as precursors of hetero-
cyclic a,a-dioxocarbenes III. Thermolysis and photolysis
of diazirines from the 1,3-dioxane-4,6-dione series resulted
predominantly in Wolff rearrangement leading to the
formation of dioxolanonecarboxylic acids or their deriva-
tives. The finding obtained evidence that the diazirines
take part in the photolysis and Wolff rearrangement of
the a-diazocarbonyl compounds.
2
2
2
0
H
ꢂꢁ5ꢂ2+
'
ꢆꢃꢇꢈ &
,9ꢀꢁ9
,
,
,,ꢃꢄ6ꢀꢃꢅ
R
1
5
2
Moreover, since the thermal rearrangement proceeds
through the vibrational levels of the ground state (S*) of
o
diazirines II it is reasonable to suggest that it may easily
occur also in the photochemical reactions of the diazo-
carbonyl compounds I (by the route c), for the isomeriza-
tion of the latter into the corresponding oxodiazirines also
goes through a “hot” ground state of diazirines. Thus in
all likelihood just the a-oxodiazirines are the key inter-
mediate stage in the photochemical Wolff rearrangement
of the a-diazocarbonyl compounds.
EXPERIMENTAL
1H (300 MHz) and 13C (75.5 MHz) NMR spectra
were registered on a spectrometer Bruker AM-300 from
The photolysis of diazirines II under short-wave UV
irradiation in a straight methanol resulted exclusively in
Wolff rearrangement that also here occurred apparently
not through diazo compound I. This conclusion is based
on the kinetics of diazirines II decomposition and on the
solutions in CDCl , internal reference (CH ) Si. IR
spectra were recorded on a spectrophotometer Specord
3
3 4
75IR from solutions in CHCl of concentration 0.02–0.03
3
-
1
mol l . UV spectra were obtained using a spectrometer
Specord M-40 in methanol in the range 200–500 nm, cell
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 42 No. 8 2006

CHEMISTRY OF DIAZOCARBONYL COMPOUNDS: XXVII.
1217
thickness 0.05–1.0 cm, concentration of solutions 3 ´
5
2
4
(
CH ), 25.3 (C ), 39.8 (CMe ), 113.4 (C ), 162.3 (C ).
3 3
–4
–3
-1
10 –6´10 mol l .
Found, %: C 50.89; H 5.60; N 13.20. C H N O .
9
12
2
4
The reactions were carried out in anhydrous solvents
Calculated, %: C 50.92; H 5.66; N 13.18.
purified by standard procedures. The preparative
separation of the reaction mixtures was performed by
column and flash-chromatography on Silicagel L 40/100
mm in a gradient mode, analytical TLC was done on Silufol
UV-254 plates (Czechia), eluents petroleum ether and
General procedure of photolysis experiments.
The irradiation of diazirines II was performed at 18–
20°C in a reactor of 25 ml capacity equipped with a quartz
filter (l > 210 nm). The monitoring of the reaction
progress was done by TLC or by measuring the volume
of nitrogen liberated.
Et O in various ratios, and also chloroform, acetone,
2
ethanol, and their mixtures.
In a reactor for photolysis was charged a solution of
3 mmol diazirine II in 20 ml of MeOH or in 20 ml of a
freshly distilled THF containing 1.2 ml of MeOH, and
the solution was irradiated till disappearance from the
mixture of initial diazirines IIa and IIb (TLC monitoring).
The solvent and excess nucleophilic reagent was distilled
off at 18–20°C in a vacuum (15–20, then 1–2 mm Hg),
the reaction mixture was dissolved in 25–30 ml of CH Cl ,
dried with anhydrous magnesium sulfate for 2 h, the
solvent was distilled off, the residue was subjected to
column chromatography on the neutral silica gel (20–
35 g) at gradient elution with a mixture petroleum ether–
ether. The main fraction containing methyl esters Va and
Vb was dried with magnesium sulfate and distilled in
a vacuum (1–2 mm Hg) on a micro distillation apparatus.
Diazirines IIa and IIb. General procedure. Into
a reactor for photolysis equipped with a filter of ordinary
glass (l > 310 nm) was charged a solution of 10 mmol
diazo compound Ia or Ib in 80 ml of a freshly distilled
THF containing 3 ml of H O, the solution was irradiated
2
for 7–9 h at 16–18°C, the solvent was distilled off in
a vacuum (15–20, then 1–2 mm Hg) at 18–20°C, the
reaction mixture was dissolved in 25–30 ml of CH Cl ,
dried with anhydrous magnesium sulfate for 2 h, the
solvent was distilled off, the residue was subjected to
chromatography on neutral silica gel (20 g) eluting
diazirines II with a mixture petroleum ether–ether, 50:1,
the residue on removing the solvents was crystallized from
a mixture petroleum ether–ether, 3:1.
2
2
2
2
Diazirines II, invisible at common vizualization of the
spot on a TLC plate (Silufol UV-254) with UV irradiation,
are easily detected as a strongly absorbing spot of the
corresponding diazodioxanedione I after heating the plate
for 1–2 min at 80–100°C [4].
Methyl 2,2-dimethyl-5-oxo-1,3-dioxolane-4-
carboxylate (Va). Yield 0.506 g (97%), bp 55–60°C (1–
1
2 mm Hg). H NMR spectrum (CDCl3), d, ppm: 1.65 s
(3H, CH3), 1.73 s (3H, CH3), 3.87 s (3H, OCH3), 4.97 s
(1H, CH) [1, 4].
6
,6-Dimethyl-4,8-dioxa-5,7-dioxo-1,2-diaza-
spiro[2,5]oct-1-ene (IIa). Yield 0.73 g (43%), mp 82–
3°C (petroleum ether–ether, 3:1), R 0.8 (petroleum
Methyl 2-methyl-2-tert-butyl-5-oxo-1,3-dioxo-
lane-4-carboxylate (Vb) (stereoisomers mixture). Yield
0.576 g (89%), bp 65–70°C (1–2 mm Hg). H NMR
1
8
f
ether–ether, 1:1) [4, 5]. UV spectrum, l (log e): 251
2.00), 289 (1.48). IR spectrum, n, cm : 1799 (C=O).
spectrum (CDCl3), d, ppm: 1.05 s, 1.10 s (9H, 3CH3),
max
1
–
1.55 s, 1.68 s (3H, CH ), 3.88 s (3H, OCH ), 4.93 s,
(
3 3
+
4.96 s (1H, CH) [1].
Mass spectrum, m/z (I , %): 170 (18) [M] , 155 (40), 69
rel
1
(
12), 58 (17), 43 (100). H NMR spectrum (CDCl ), d,
Irradiation of diazirines II in the presence of
3
1
3
ppm: 2.00 s (6H, 2CH ). C NMR spectrum (CDCl ),
3
3
4
a sensitizer (Ph C=O). General procedure. Into
2
5
2
d, ppm 25.3 (C ), 28.4 (2CH ), 108.1 (C ), 162.0 (C ).
Found, %: C 42.09; H 3.60; N 16.50. C H N O .
Calculated, %: 42.40; H 3.61; N 16.50.
3
a quartz cell of 15 ml capacity was charged a solution of
1 mmol of diazirine II in 7–13 ml of a freshly distilled
MeOH (i-PrOH) containing 0.5 (2.0) mmol of sensitizer
( at this concentration the extinction of benzophenone at
the wavelength 254 nm exceeds 80 times that of compound
II). The solution was irradiated with a short-wave UV
light (l > 210 nm) till disappearance from the mixture of
initial diazirines IIa and IIb (TLC monitoring). On
completion of the photolysis the reaction mixture was
6
6
2
4
6
-Methyl-6-tert-butyl-4,8-dioxa-5,7-dioxo-1,2-
diazaspiro[2,5]oct-1-ene (IIb). Yield 0.85 g (40%),
mp 71–73°C (petroleum ether–ether, 3:1), R 0.75
petroleum ether–ether, 3:1). UV spectrum, l (log e):
50 (2.18), 289 (1.48). IR spectrum, n, cm : 1770 (C=O).
Mass spectrum, m/z (I , %): 197 (1) [M–15] , 155 (40),
00 (5), 85 (9), 57 (100), 43 (60). H NMR spectrum
f
(
2
max
–
1
+
rel
1
1
1
analyzed by means of H NMR spectroscopy. The
(
CDCl ), d, ppm: 1.21 s (9H, 3CH ), 1.98 c (3H, CH ).
quantitative analysis was performed using an internal
reference, p-dibromobenzene.
3
3
3
1
3
C NMR spectrum (CDCl ), d, ppm: 23.8 (3CH ), 24.7
3
3
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 42 No. 8 2006

1218
SHEVCHENKO et al.
Table 3. Results of thermolysis of diazirine IIb in C D –MeOH
solution at 50°C
nucleophile, 1:10. The content of components in the
reaction mixture was estimated by the internal
normalization method. From the results of kinetic runs
we calculated the half-life of diazirines II (t , 50°C)
6
6
&
RQWHQWꢀRIꢀFRPSRQHQWVꢀLQꢀUHDFWLRQꢀ
7
KHUPRO\VLVꢀWLPHꢁꢀ
PL[WXUHꢀDWꢀWKHUPRO\VLVꢁꢀꢂꢀ
1
/2
PLQꢀ
,
,Eꢀ
,Eꢀ
9Eꢀ
ꢄꢉꢄꢀ
[10].
ꢄꢀ
ꢎꢄꢀ
ꢈꢄꢀ
ꢋꢄꢀ
ꢍꢋꢀ
ꢃꢄꢄꢉꢄꢀ
ꢍꢄꢉꢄꢀ
ꢋꢏꢉꢆꢀ
ꢋꢎꢉꢈꢀ
ꢈꢆꢉꢄꢀ
ꢎꢆꢉꢄꢀ
ꢆꢉꢄꢀ
ꢄꢉꢄꢀ
Thermolysis of diazirine IIb in C D –MeOH was per-
6
6
ꢆꢉꢊꢀ
ꢍꢉꢏꢀ
ꢃꢃꢉꢊꢀ
ꢃꢋꢉꢌꢀ
ꢎꢎꢉꢎꢀ
ꢎꢍꢉꢎꢀ
ꢃꢈꢉꢌꢀ
ꢎꢃꢉꢋꢀ
ꢎꢆꢉꢏꢀ
ꢌꢍꢉꢊꢀ
ꢆꢎꢉꢍꢀ
ꢋꢋꢉꢍꢀ
formed for 60 min directly in the probe of the spectrom-
eter; the content of components Ib, IIb, and Vb in the
reaction mixture was estimated from the integral inten-
sity of proton signals of the following groups: diazo com-
pound Ib, CH (1.11 ppm); diazirine IIb, CH (1.8 ppm);
ꢃꢆꢃꢀ
ꢌꢎꢋꢀ
3
3
methyl ester of 5-oxocarboxylic acid Vb, CH (1.07 and
3
ꢀ
1
.57 ppm). The results of the analysis are presented in
Table 4. Results of irradiation of diazirine IIb in THF–MeOH
Fig. 1 and Table 3. To estimate the yield of reaction prod-
ucts at higher conversion the thermolysis of diazirine IIb
was continued at 80°C for 9 h. On completion of the
reaction the components of the reaction mixture were
present in the following amounts: diazo compound Ib,
(
l ³ 210 nm)
&RQWHQWꢀRIꢀFRPSRQHQWVꢀLQꢀUHDFWLRQꢀ
3KRWRO\VLVꢀWLPHꢁꢀPLQꢀꢀ
PL[WXUHꢀDWꢀSKRWRO\VLVꢁꢀꢂꢀꢀ
,
,Eꢀ
9Eꢀ
ꢄꢀ
3
4%; methyl ester of 5-oxocarboxylic acid Vb, 66%.
ꢄꢀ
ꢃꢄꢀ
ꢎꢄꢀ
ꢌꢄꢀ
ꢈꢄꢀ
ꢆꢄꢀ
ꢊꢄꢀ
ꢍꢄꢀ
ꢃꢄꢄꢀ
ꢊꢍꢉꢍꢀ
ꢆꢏꢉꢆꢀ
ꢈꢌꢉꢎꢀ
ꢎꢏꢉꢃꢀ
ꢎꢌꢉꢏꢀ
ꢃꢎꢉꢈꢀ
ꢃꢄꢉꢊꢀ
ꢎꢃꢉꢎꢀ
ꢈꢄꢉꢆꢀ
ꢆꢋꢉꢍꢀ
ꢊꢄꢉꢏꢀ
ꢊꢋꢉꢃꢀ
ꢍꢊꢉꢋꢀ
ꢍꢏꢉꢌꢀ
Kinetics of photolysis of diazirines IIa and IIb.
Into a reactor for photolysis equipped with a jacket of
quartz was charged a solution of 1.4–1.6 mmol of diazirine
II in 20 ml of a freshly distilled THF or Me S containing
2
0.6 ml of MeOH, and the mixture was subjected to
irradiation at 16–18°C till disappearance from the mixture
of initial diazirine II (TLC monitoring). In the course of
the photolysis the sampling (0.5 or 1 ml) was performed
at regular intervals, the volatile components from the
samples of the reaction mixture were removed in
a vacuum (1–2 mm Hg) at 16–18°C. The content of
components in the reaction mixture was estimated by
the internal normalization method or with the help of an
internal reference (p-dibromobenzene, 3–5 mg/ml
CDCl3).
ꢀ
Photochemical decomposition of diazirine IIa in
methanol solution. On irradiation of 0.170 g (1 mmol)
of diazirine IIa for 120 min in a methanol solution (7 ml)
containing 0.091 g (0.5 mmol) of benzophenone we
1
identified in the reaction mixture by means of H NMR
spectroscopy only 2,2-dimethyl-1,3-dioxane-4,6-dione
(VIa). Yield 0.134 g (93%).
Photochemical decomposition of diazirine IIb in
-propanol. On irradiation of 0.212 g (1 mmol) of diazirine
IIb for 240 min in a 2-propanol solution (13 ml) containing
Photolysis of diazirine IIb in THF–MeOH. Asolu-
tion of 0.34 g (1.6 mmol) of diazirine IIb in 22 ml of THF
and 0.6 ml of MeOH was irradiated for 80 min with
sampling of the reaction mixture (0.5 ml) after 10, 20, 30,
40, 50, 60, 70, and 80 min from the start of the reaction,
the quantitative analysis of the reaction mixture was
performed with the help of the internal reference. The
results of analyses are presented in Fig. 2 and Table 4.
2
0
.364g (2 mmol) of benzophenone we identified in the
1
reaction mixture by means of H NMR spectroscopy only
2
0
-methyl-2-tert-butyl-1,3-dioxane-4,6-dione (VIb). Yield
.180 g (97%).
Kinetics of the thermolysis of diazirine IIa and
1
On completion of the photolysis according to H NMR
spectroscopy the only product was methyl ester of
IIb. The thermolysis of diazirines II was carried out in
an NMR tube placed in a temperature-controlled device
or directly in the probe of the NMR spectrometer at 50 ±
5
-oxocarboxylic acid Vb, yield 0.308 g (89%).
1
°C in CDCl or C D solution. The content of the reaction
The study of the heat resistance of diazo com-
3
6 6
mixture components was registered at regular time
pounds Ia and Ib. The thermolysis of diazo compounds
I was carried out in an NMR tube at 50 ± 1°C in CDCl3
solution and at 80 ± 1°C in C D solution with methanol
intervals. The concentration of diazirines IIa and IIb in
-
1
solution was 0.09–0.1 mol l , the ratio diazirine II–
6
6
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 42 No. 8 2006

CHEMISTRY OF DIAZOCARBONYL COMPOUNDS: XXVII.
1219
added (content of diazo compounds I in solution 0.01–
.02 g, molar ratio I–MeOH 1:10), after 10 h the reaction
6. Bogdanova,A. and Popik, V.V., J. Am. Chem. Soc., 2003, vol.
25, p. 1457; Bogdanova,A. and Popik, V.V., J. Am. Chem.
Soc., 2003, vol. 125, p. 14153.
7. Meier, H., Chemistry of Diazirines, Liu, M.T.H., Ed., Boca
Raton: CRC Press, 1987, p. 1; Zollinger, H., Diazo Chemis-
try. II, Weinheim: VCH Verlagsgesellshaft, 1995, p. 173;
Regitz, M. and Maas, G., Diazo Compounds: Properties
and Syntheses, Academic Pr., 1986, p. 166.
1
0
mixture was cooled to room temperature and analyzed
1
by means of H NMR spectroscopy. In all runs (Ia–
CDCl –MeOH, Ia–C D –MeOH, Ib–CDCl –MeOH,
3
6
6
3
Ib–C D –MeOH) at the end of heating in the reaction
6
6
mixtures were identified only initial diazo compounds Ia
and Ib.
8. Shustov, G.V., Tavakalyan, N.B., Pleshkova, A.P., and
Kostyanovskii, R.G., Khim. Geterotsikl. Soedin., 1981,
p. 901.
REFERENCES
9
. Baird, N.C., Chemistry of Diazirines, Liu, M.T.H., Ed. Boca
Raton: CRC Press, 1987, p. 1; Winnewisser, M., Moller, K.,
and Gambi, A., Chemistry of Diazirines, Liu, M.T.H., Ed.,
Boca Raton: CRC Press, 1987, p. 19.
1
. Nikolaev, V.A., Shevchenko, V.V., Khimich, N.N., and
Platz, M.S., Zh. Org. Khim., 2006, vol. 42, p. 840.
2
. Liu, M.T.H. and Stevens, I.D.R., Chemistry of Diazirines,
Liu, M.T.H., Ed., Boca Raton: CRC Press, 1987, p. 111; Doyle,
M.P., The Selectivity of Carbenes Generated from
Diazirines, Liu, M.T.H., Ed., Boca Raton: CRC Press, 1987,
p. 33; Platz, M.S. and Maloney, V.M., Kinetics and Spec-
troscopy of Carbenes and Biradicals, Platz, M.S., Ed., New
York: Plenum Press, 1990, p. 239; Carbene Chemistry,
Bertrand, G., Ed., NewYork: Marcel Dekker Inc, 2002, 320 p.
1
0. Emanuel’, N.M. and Sergeeva, G.B., Eksperimental’nye
metody khimicheskoi kinetiki (Experimental Methods of
Chemical Kinetics), Moscow: Vysshaya Shkola, 1980,
p. 124; Dneprovskii,A.S., Eliseeva, E.E., and Ershov, B.A.,
Laboratornye raboty k praktikumu po fizicheskoi
organicheskoi khimii (Laboratory Manual on Physical
Organic Chemistry), 1988, p. 16.
1. Rodina, L.L. and Korobitsyna, I.K., Usp. Khim., 1967,
vol. 36, p. 260; Meier, H. and Zeller, K.P., Angew. Chem. Int.
Ed., 1975, vol. 87, p. 52; Kirmse, W., Eur. J. Org. Chem.,
3
. Schmitz, E., Angew. Chem. Int. Ed., 1964, vol. 3, p. 333;
Schmitz, E. and Horig, C., Chem. Ber., 1967, vol. 100,
p. 2101; Schmitz, E., Three-Membered Rings with Two
Hetero Atoms, Katritzky,A., Ed., Elsevier, 2006.
1
2002, p. 2193.
4
. Nikolaev, V.A., Khimich, N.N., and Korobitsina, I.K., Khim.
Geterotsikl. Soedin., 1985, p. 321; Khimich, N.N., Cand.
Sci. (Chem.) Dissertation, Leningrad, 1989; Shevchenko,
V.V., Khimich, N.N., Platz, M.S., and Nikolaev,V.A., Tetrahe-
dron Lett., 2005, vol. 46, p. 435.
12. Voigt, E. and Meier, H., Chem. Ber., 1975, vol. 108, p. 3326;
Li, Y-Z., and Schuster, G.B., J. Org. Chem., 1986, vol. 51,
p. 3804.
13. Ando, W., Chemistry of Diazonium and Diazo Groups,
Patai, S., Ed., Toronto: Wiley, 1978, vol. 1, p. 439;
Schuster, G.B., Adv. Phys. Org. Chem., 1986, vol. 23, p. 311;
Kirmse, W., Adv. Carbene Chem., 1994, vol. 1, p. 39.
5. Livinghouse, T. and Stevens, R.V., J. Am. Chem. Soc., 1978,
vol. 100, p. 6479.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 42 No. 8 2006