Organometallic synthesis in the furazan series 2. Furazanylethanes

Article abstract of DOI:10.1023/A:1023967008642

The reactions of Li derivatives of methylfurazans with electrophilic reagents and oxidants were investigated. A series of functionalized furazanylethane derivatives were prepared.

Full text of DOI:10.1023/A:1023967008642

Russian Chemical Bulletin, International Edition, Vol. 52, No. 3, pp. 679—688, March, 2003
679
Organometallic synthesis in the furazan series
2.* Furazanylethanes
ꢀ
A. B. Sheremetev, E. A. Ivanova, A. Yu. Sizov, V. O. Kulagina, D. E. Dmitriev, and Yu. A. Strelenko
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences,
47 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (095) 135 5328. Eꢀmail: sab@ioc.ac.ru
The reactions of Li derivatives of methylfurazans with electrophilic reagents and oxidants
were investigated. A series of functionalized furazanylethane derivatives were prepared.
Key words: furazans, furazanylethanes, organolithium synthesis, electrophilic reagents,
NMR spectroscopic study.
Scheme 1
Organolithium synthons are widely used in the target
synthesis of compounds containing heterocyclic fragꢀ
ments.3,4 Lithiation of the simplest heterocyclic derivaꢀ
tives followed by the reactions of the resulting Liꢀconꢀ
taining intermediates with electrophiles enables one to
substantially complicate the molecular structure in one
operation. However, this methodology has found virtuꢀ
ally no application in the construction of complex furazan
derivatives. At the same time, it is these derivatives that
are most attractive as potentially biologically active comꢀ
pounds. The stateꢀofꢀtheꢀart of chemistry of furazan deꢀ
rivatives has been surveyed in the review.5
Earlier,1,2,6 we have demonstrated that the electronꢀ
withdrawing nature of the furazan ring is favorable for
smooth lithiation of the methyl group bound to this ring.
The resulting lithium derivatives reacted with alkyl haꢀ
lides or haloacetic esters to give the corresponding deꢀ
rivatives.
Lithiation of compound 1 with butyllithium was carꢀ
ried out analogously to a procedure described earlier.1
Treatment of the resulting intermediate 3 with different
electrophilic reagents at –50 °C afforded compounds
4—10 (Scheme 2) in 65—85% yields.
The procedure used afforded the expected compounds
4—7, 9, and 10a,b. However, the reaction of intermediate
3 with butyrolactone unexpectedly gave rise to ylideneꢀ
tetrahydrofuran 8. Apparently, keto alcohol 11 that iniꢀ
tially formed readily underwent enlolization followed by
cyclodehydration under the reaction conditions.
In the present study, we report on the use of Li derivaꢀ
tives of methylfurazans in the synthesis of a series of new
functionalized furazanylethanes.
3,4ꢀDimethylfurazan (1) was chosen as the basic preꢀ
cursor. Several procedures have been developed5 for the
synthesis of this compound by dehydration of dimethylꢀ
glyoxime (2) (Scheme 1). However, the procedures deꢀ
scribed earlier enable one to prepare compound 1 in yields
of at most 80% and require large amounts of dehydrating
reagents. We optimized dehydration of 2 promoted by
bases,7 which made it possible to increase the yield of 1
to 95%. Thus, slow heating of a suspension of 2 in ethylꢀ
ene glycol to boiling in the presence of catalytic amounts
of a mixture of KOH and Cs2CO3 ensures smooth distillaꢀ
tion of the product and allows one to obtain more than
400 g of furazan 1 in one operation.
Difurazanylethane 6 was also readily prepared in
85—95% yields by oxidative condensation of intermediꢀ
ate 3 under the action of I2, CuCl2, or dibromoethane.
Recently,8 compound 6 has been synthesized by the reꢀ
action of cyclopropyllithium with 3ꢀbromomethylꢀ4ꢀ
methylfurazan.
* For Part 1, see Ref. 1. Selected results of the present study
were submitted to the Conference on Organic Synthesis.2
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 651—659, March, 2003.
1066ꢀ5285/03/5203ꢀ679 $25.00 © 2003 Plenum Publishing Corporation

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Russ.Chem.Bull., Int.Ed., Vol. 52, No. 3, March, 2003
Sheremetev et al.
Scheme 2
Ketone 9 was readily nitrosated at the methylene fragꢀ
step and their further modifications. We used compound 5
as a model object. Under the reaction conditions used for
lithiation of furazan 1, compound 5 was lithiated excluꢀ
sively at the methyl group. Treatment of the intermediate
thus formed with electrophiles afforded products 15—21
(Scheme 4). However, the products were prepared in lower
yields than those achieved in the reactions of intermediꢀ
ate 3. The reactions with the use of different benzyl chloꢀ
rides as electrophiles gave rise to the corresponding stilꢀ
benes as byꢀproducts. For example, an attempt to syntheꢀ
size compound 16 by treatment of dimethylfurazan 1 with
two equivalents of butyllithium to produce a C,C´ꢀdiꢀ
lithiated intermediate followed by treatment with two
equivalents of benzyl chloride led to the formation of only
trace amounts of the target product,16 stilbene being obꢀ
tained in 84% yield.
ment. The resulting ketoxime 12 was transformed into
glyoxime 13 (Scheme 3).9 However, attempts to perform
dehydration of glyoxime 13 to produce bifurazan 14 under
the conditions used for the synthesis of compound 1 failed.
Scheme 3
Two approaches to the synthesis of unsymmetrically
substituted difurazanylethane 22 were used (Scheme 5).
Both approaches gave rise to product 22 in similar yields
(66—68%).
Oxidative condensation of the corresponding lithiated
derivatives under the action of CuCl2 is an efficient proꢀ
cedure for the synthesis of difurazanylethanes 23 and 24
(Scheme 6), which were isolated in 78 and 85% yields,
respectively.
In the next step of investigation, we carried out secꢀ
ondary lithiation of the compounds prepared in the first

Furazanylethanes
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 3, March, 2003
681
Scheme 4
lecular ion peak [M]+ was observed in the mass spectra of
all compounds. Earlier,1 we have reported that the
[M+ – NO] fragment is characteristic of furazans containꢀ
ing alkyl substituents. Competitive heterolytic fragmentaꢀ
tion of the alkyl chain producing the ions [M – CH3]+,
[M – C2H4]+, [M – NO – CH3]+, etc., was less proꢀ
nounced.
Scheme 5
Taking into account the characteristic features, which
have been revealed in the earlier NMR spectroscopic studꢀ
ies of furazan derivatives,1,10—12 the interpretation of the
1H and 13C NMR spectra of rather simple compounds,
such as 4—16, 23, and 24, presented no problems. Howꢀ
ever, the assignment of the signals in the spectra of unꢀ
symmetrical compounds 17—22 called for a more deꢀ
tailed investigation. Only some of the signals observed in
the spectra of the latter compounds can be interpreted by
comparing with the spectra of the corresponding symꢀ
metrical derivatives. The complete assignment of all sigꢀ
nals for the protonated carbon atoms was made based on
the assignments of the signals for the corresponding proꢀ
tons with the use of the inversion twoꢀdimensional
heteronuclear H,C correlation experiment. The longꢀ
The compositions and structures of all compounds
were confirmed by elemental analysis, NMR and IR specꢀ
troscopy, and mass spectrometry. Thus, an intense moꢀ
1
range spinꢀspin coupling constants between the H and

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Sheremetev et al.
H(10), H(5)
H(6)
H(9)
a
δ
C
22
C(9)
24
C(6)
26
28
30
C(10)
32
C(5)
34
3.1
3.0
2.9
2.8
δ
H
H(10), H(5)
H(6)
H(9)
b
δ
C
C(12)
132
134
136
138
140
142
144
146
148
150
152
154
C(14)
C(16)
C(11)
C(4)
C(8)
C(7)
3.1
3.0
2.9
2.8
δ
H
Fig. 1. NMR H,C correlation spectra (a) and HMBC spectra (b) of the CH2 groups of compound 19.

Furazanylethanes
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 3, March, 2003
683
Scheme 6
Table 1. Calculated and experimental spinꢀspin coupling conꢀ
stants (J/Hz) of the difurazanylethylene fragment of compound 6
J
Jcalc
Jexp
1
3
5
ϕ
ϕ
ϕ
J2,4
J2,5
J3,4
1.85
14.80
5.25
1.81
—
14.82
2.50
2.50
14.82
—
1.81
5.25
14.80
1.85
—
8.54
6.44
6.44
8.54
132.6
5.2
J3,5
1JC,H
2JC,H
—
—
—
constants JH,H were determined from the analysis of the
13C satellites of this signal. When one of the methylene C
atoms is the 13C magnetic isotope, the degeneration is
removed giving rise to the AA´BB´X spin system, where A
and B are protons and X is the 13C nucleus. The iterative
1
calculations of the H and 13C NMR subspectra made it
possible to determine all spinꢀspin coupling constants of
the fiveꢀspin system. The conformationally dependent
vicinal spinꢀspin coupling constants are given in Table 1.
The spinꢀspin coupling constants for each rotamer were
calculated according to the generalized Karplus equaꢀ
tion.13 Assuming that the observed spinꢀspin coupling
constants are the sum of the corresponding spinꢀspin couꢀ
pling constants of all conformations with consideration
for the proportion of each conformer in the conformaꢀ
tional equilibrium, the system of Eqs. (1)—(3) can be
written. The solution of these equations gives the proporꢀ
tion of each structure in the dynamic equilibrium and the
energy difference (∆G298) between these structures.
13C atoms in the HMBC experiment allowed us to comꢀ
plete the analysis of the spectra with the assignment of the
signals for the quaternary carbon atoms. As an example,
Figure 1 shows the patterns observed in the assignments
Let us denote the equilibrium fraction of the transoid
fragment by A and the fractions of the skewed conformers
1
of the signals in the H and 13C NMR spectra of comꢀ
pound 19.
by B and C. Then:
Since data on the stereochemistry of the difurazanylꢀ
ethylene fragment were lacking, it was of interest to eluciꢀ
date this question. Calculations by the molecular meꢀ
chanics with the MM2 force field revealed three lowꢀ
energy conformations of the ethylene fragment in comꢀ
pound 6, viz., two equivalent skewed conformations, ϕ1
and ϕ5, and one transoid conformation ϕ3 (Fig. 2).
Since the methylene protons in this symmetrical comꢀ
pound are chemically equivalent and are observed as a
3
J2,4 = AJ2,4 + BJ2,4 + CJ2,4
,
(1)
(2)
(3)
3J2,5 = AJ2,5 + BJ2,5 + CJ2,5
A + B + C = 1.
,
The solution of these equations gives:
A = 0.510, B = C = 0.245,
∆G298(A/B) = RTln(A/B),
(4)
∆G298(A/B) = 1.81 kJ mol–1
.
Hence, the 1,2ꢀdi(furazanyl)ethylene fragment in
compound 6 occurs predominantly in the transoid conꢀ
formation.
1
singlet in the H NMR spectrum, the spinꢀspin coupling
In conclusion, it should be noted that the possibility
of a successive increase in the length of the carbon chain
of the substituent opens up an approach to the target
synthesis of the previously inaccessible complex furazan
derivatives starting from simple methylfurazans.
Experimental
Fig. 2. Conformations of the difurazanylethylene fragment of
compound 6.
The melting points were determined on a Kofler stage. The
1H and 13C NMR spectra were recorded at natural isotopic

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Sheremetev et al.
abundance on a Bruker AMꢀ300 spectrometer operating at 300.13
and 75.7 MHz, respectively, and on a Bruker DRXꢀ500 specꢀ
trometer operating at 500.13 and 125.7 MHz, respectively. The
chemical shifts are given in the δ scale relative to the solvent as
the internal standard. The mass spectra were obtained on
Finnigan MAT INCOSꢀ50 and Varian MAT CHꢀ111 instruꢀ
ments (EI, 70 eV). The IR spectra were measured on a Specord
IRꢀ75 spectrometer (in KBr pellets for solids and in a thin layer
for liquid samples). The course of the reactions and the purities
of the products were monitored by GLC and TLC (Silufol
UVꢀ254 plates, detection from UV absorption). Preparative chroꢀ
matography was carried out with the use of SiO2 (40—100 µm;
Armenia). The GLC analysis was performed on a Biokhromꢀ1
chromatograph (flame ionization detector, capillary column,
helium as the carrier gas). Commercially available dimethylꢀ
glyoxime was used. 4ꢀChloromethylꢀ3ꢀmethylfurazan was preꢀ
pared according to a procedure described earlier.14
3,4ꢀDimethylfurazan (1). Dimethylglyoxime 2 (300 g,
2.5 mol), ethylene glycol (350 mL), KOH (5.6 g, 0.1 mol), and
Cs2CO3 (6.52 g, 0.02 mol) were placed in a 1ꢀL threeꢀneck flask
equipped with a thermometer, a down condenser, and a powerꢀ
ful mechanical stirrer. The resulting viscous substance was rapꢀ
idly heated to 110 °C with active stirring. Further heating was
carried out slowly with a rate of ∼1 °C min–1, the dark solution
being gradually formed. Once the reaction mixture was heated
above 160 °C, distillation of both the product and water that was
eliminated in the course of the reaction started and ∼300 mL of
the distillate were collected, after which the residue was cooled
to 80—90 °C and dimethylglyoxime (232 g, 2 mol) was added.
Following the aboveꢀmentioned recommendations, ∼250 mL of
the distillate were additionally distilled off, the residue was cooled
to 80—90 °C, water (200 mL) was added, and the residue of the
product was removed by azeotropic distillation with water.
Dichloromethane (100 mL) was added to the combined distilꢀ
lates, and the mixture was washed with water (2×100 mL). The
organic layer was dried over MgSO4 and filtered through a layer
of silica gel. The dichloromethane was removed on a rotary
evaporator at 20 °C. The remaining oil was distilled unꢀ
der atmospheric pressure. Compound 1 was obtained in a
yield of 419 g (95%), b.p. 156—158 °C (cf. lit. data7: b.p.
159—161 °C).
Rf 0.60 (CH2Cl2). Found (%): C, 62.34; H, 9.18; N, 18.14.
C8H14N2O (154.21). Calculated (%): C, 62.31; H, 9.15;
N, 18.17. MS, m/z: 154 [M+], 122 [M+ – NO – H2], 107, 98,
84. H NMR (CDCl3), δ: 0.95 (t, 3 H, C(8)H3, J = 6.8 Hz);
1.30—1.50 (m, 4 H, C(6)H2, C(7)H2); 1.68 (m, 2 H, C(5)H2);
1
2.32 (s,
3 H, C(1)H3); 2.54 (t, 2 H, C(4)H2, J =
6.6 Hz). 13C NMR (CDCl3), δ: 154.2 (C=N); 153.6 (C=N);
31.1 (C(4)); 27.1 (C(5)); 23.0 (C(6)); 22.1 (C(7)); 14.0 (C(8));
7.9 (C(1)).
3ꢀMethylꢀ4ꢀ(2ꢀphenylethyl)furazan (5). A solution of comꢀ
pound 1 (1.57 g, 0.016 mol) in anhydrous THF (150 mL) was
placed in an apparatus used for the synthesis of compound 4 and
then a solution of BuLi (1.023 g, 0.016 mol, 0.0472 g mL–1) in
pentane was added dropwise with stirring under an atmosphere
of argon at –55 °C. The brightꢀyellow reaction mixture was
stirred at –55 °C for 20 min and then a solution of BnCl (2.1 g,
0.0166 mol) in anhydrous THF (20 mL) was rapidly added. The
reaction mixture was stirred at –55 °C for 30 min. Then cooling
was terminated. The reaction mixture was allowed to warm to
∼20 °C, stirred for 1 h, and neutralized with EtOH (3 mL). All
volatile components were evaporated under reduced pressure.
The residue was dissolved in CH2Cl2 (50 mL), washed with
water (2×30 mL), dried over MgSO4, and filtered through a
SiO2 layer. The solvent was evaporated. The product was twice
purified by preparative chromatography (CHCl3—pentane 1 : 1,
as the eluent,). Compound 5 was obtained as an oil in a yield of
20
2.4 g (80%), b.p. 115 °C (20 Torr), nD 1.526. Found (%):
C, 70.22; H, 6.47; N, 14.81. C11H12N2O (188.23). Calcuꢀ
lated (%): C, 70.19; H, 6.43; N, 14.88. MS, m/z: 188 [M+], 158
[M+ – NO], 156 [M+ – NO – H2], 147, 141, 139, 121, 111, 98.
IR, ν/cm–1: 3064, 3032, 2936, 2864, 1584, 1496, 1452, 1400,
1216, 1184, 1080, 1036, 888. 1H NMR (CDCl3), δ: 2.14 (s, 3 H,
Me); 2.97—3.12 (m, 4 H, CH2CH2); 7.15 (d, 2 H, mꢀPh, J =
7.2 Hz); 7.22—7.38 (m, 3 H, o,pꢀPh). 13C NMR (CDCl3), δ:
153.7 (C(3)); 150.6 (C(2)), 139.8 (C(6)); 128.6, 128.3, 128.6,
33.8 (C(5)), 25.1 (C(4)), 7.8 (C(1)).
1,2ꢀBis(4ꢀmethylfurazanꢀ3ꢀyl)ethane (6). A. The solid comꢀ
pound was prepared analogously to the synthesis of comꢀ
pound 5 starting from 4ꢀchloromethylꢀ3ꢀmethylfurazan (2.2 g,
0.0166 mol) followed by evaporation of the solvent. The resultꢀ
ing compound was purified by recrystallization from CCl4. Prodꢀ
uct 6 was obtained as small white crystals in a yield of 2.53 g
(79%), m.p. 100—102 °C. Found (%): C, 49.47; H, 5.24;
N, 28.78. C8H10N4O2 (194.19). Calculated (%): C, 49.48;
H, 5.19; N, 28.85. MS, m/z: 194 [M+], 164 [M+ – NO], 153
[M+ – MeCN], 137 [M+ – MeCNO], 111 [M+ – MeCNO –
3ꢀMethylꢀ4ꢀpentylfurazan (4). A solution of compound 1
(0.34 g, 3.47 mmol) in anhydrous THF (150 mL) was placed in a
250ꢀmL threeꢀneck flask equipped with a thermometer and two
dropping funnels with pressureꢀequalization arms and then a
solution of BuLi (0.22 g, 3.47 mmol, 0.0255 g mL–1) in pentane
was added dropwise with stirring at –55 °C under a static atmoꢀ
sphere of argon. The brightꢀyellow reaction mixture was stirred
at –55 °C for 20 min, after which a solution of BunCl (0.34 g,
3.67 mmol) in anhydrous THF (30 mL) was rapidly added. The
reaction mixture was stirred at –55 °C for 30 min. Then cooling
was terminated. The reaction mixture was allowed to warm to
∼20 °C, stirred for 1 h, neutralized with a saturated aqueous
NH4Cl solution (10 mL), and concentrated on a rotary evaporaꢀ
tor to 20—30 mL. Water (100 mL) was added to the residue and
the reaction mixture was extracted with CH2Cl2 (3×30 mL).
The extract was dried over MgSO4 and filtered through a layer of
silica gel, after which the solvent was evaporated. Liquid prodꢀ
uct 4 was isolated by column chromatography (CH2Cl2—penꢀ
1
CN]. H NMR (CDCl3), δ: 2.32 (s, 6 H, Me); 3.12 (s, 4 H,
CH2). 13C NMR (CDCl3), δ: 153.7 and 150.4 (both C(3)); 20.8
(C(4)); 7.9 (C(1)). IR, ν/cm–1: 2960, 2915, 1585, 1450, 1435,
1385, 1275, 1175, 1040, 980, 890.
B. Analogously to the procedure used for the synthesis of
compound 4, compound 1 (2.2 g, 0.022 mol) was lithiated with
a solution of BuLi (1.44 g, 0.022 mol, 0.0511 g mL–1) in penꢀ
tane. The brightꢀyellow reaction mixture was stirred at –55 °C
for 20 min, after which a solution of I2 (2.85 g, 0.044 mol) in
anhydrous THF (20 mL) was added. The reaction mixture was
stirred at –55 °C for 30 min, heated to ∼20 °C for 20 min, stirred
for 1 h, and treated with a saturated aqueous NH4Cl solution
(10 mL). Then water (50 mL) was added and the reaction mixꢀ
ture was concentrated under reduced pressure to 70—80 mL.
20
tane, 1 : 1, as the eluent) in a yield of 0.5 g (94%), nD 1.499,

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Russ.Chem.Bull., Int.Ed., Vol. 52, No. 3, March, 2003
685
The residue was extracted with CH2Cl2 (3×50 mL). The comꢀ
bined extracts were washed with a 10% sodium hyposulfite soluꢀ
tion (30 mL) and water (3×30 mL). The extract was dried over
MgSO4 and filtered through a SiO2 layer. Then the solvent was
evaporated and the residue was recrystallized from CCl4.
Compound 6 was obtained in a yield of 1.83 g (84%), m.p.
99—100 °C.
C. Analogously to the procedure used for the synthesis of
compound 4, compound 1 (2.65 g, 0.027 mol) was lithiated with
a solution of BuLi (1.728 g, 0.027 mol, 0.043 g mL–1) in penꢀ
tane. The brightꢀyellow reaction mixture was stirred at –55 °C
for 20 min, after which a solution of 1,2ꢀdibromoethane (2.538 g,
0.0135 mol) in anhydrous THF (20 mL) was rapidly added. The
reaction mixture was stirred at –55 °C for 30 min and treated as
described in the method A. The product was obtained in a yield
of 2.54 g (97%), m.p. 99—101 °C.
D. Analogously to the procedure used for the synthesis of
compound 4, compound 1 (2.74 g, 0.028 mol) was lithiated with
a solution of BuLi (1.79 g, 0.028 mol, 0.025 g mL–1) in pentane.
The brightꢀyellow reaction mixture was stirred at –55 °C for
20 min, after which a solution of anhydrous CuCl2 (3.78 g,
0.028 mol) in anhydrous THF (20 mL) was rapidly added. The
reaction mixture was stirred at –55 °C for 30 min and treated as
described in the method A. The product was obtained in a yield
of 2.6 g (96%), m.p. 101—102 °C.
treated with a saturated aqueous NH4Cl solution (10 mL), and
concentrated to 15—20 mL. Dichloromethane (100 mL) was
added to the residue. The reaction mixture was washed with
water (2×40 mL) and dried over MgSO4. The solvent was reꢀ
moved under reduced pressure. The product was isolated by
chromatography on a plate (SiO2 40/100 µm, CHCl3 as the
eluent). Oily compound 8 was obtained in a yield of 1.56 g
20
(42%), nD 1.4915, Rf 0.50 (CHCl3). Found (%): C, 57.85;
H, 6.08; N, 16.81. C8H10N2O2 (166.18). Calculated (%):
C, 57.82; H, 6.07; N, 16.86. MS, m/z: 166 [M+], 165, 154, 141,
140, 130, 125, 98, 83. 1H NMR (CDCl3), δ: 2.15 (m, 2 H,
C(7)H2); 2.30 (s, 3 H, Me); 3.05 (t, 2 H, C(6)H2, J = 6.6 Hz);
4.27 (t, 2 H, C(8)H2, J = 6.8 Hz); 5.45 (br.s, 1 H, CH). 13C NMR
(CDCl3), δ: 151.6, 149.9, 80.9 (C(4)); 71.9 (C(8)); 30.6 (C(6));
24.3 (C(7)); 9.1 (C(1)).
1ꢀ(4ꢀMethylfurazanꢀ3ꢀyl)acetone (9). Analogously to the
synthesis of compound 5, a solution of compound 1 (10 g, 0.102
mol) in anhydrous THF (150 mL) was placed in a 300ꢀmL flask
and lithiated with a solution of BuLi (6.53 g, 0.102 mol,
0.0224 g mL–1) in pentane. The brightꢀyellow reaction mixture
was stirred at –55 °C for 20 min, after which a twofold excess of
anhydrous MeCN dissolved in anhydrous THF (50 mL) was
added dropwise. The reaction mixture was stirred for 30 min.
Then cooling was terminated. The reaction mixture was allowed
to warm to ∼20 °C and stirred for 1 h. The solvent was evapoꢀ
rated under reduced pressure. The residue was suspended in
concentrated HCl (100 mL) and heated at 50—60 °C for 32 h.
The product was isolated by azeotropic distillation with a water
vapor. The distillate was extracted with CH2Cl2 (3×50 mL),
dried over MgSO4, and filtered through a layer of silica gel. The
solvent was removed under reduced pressure. The liquid product
with a characteristic odor was obtained in a yield of 13.56 g
1,2ꢀBis(4ꢀmethylfurazanꢀ3ꢀyl)ꢀethanꢀ1ꢀone (7). Analogously
to the synthesis of compound 5, a solution of BuLi (1.0 g,
0.0156 mol, 0.0224 g mL–1) in pentane was added dropwise with
stirring under argon at –55 °C to a solution of compound 1
(1.53 g, 0.0156 mol) in anhydrous THF (100 mL). The brightꢀ
yellow reaction mixture was stirred at –55 °C for 20 min, after
which a solution of ethyl 3ꢀmethylfurazancarboxylate (2.43 g,
0.0156 mol) in anhydrous THF (10 mL) was rapidly added. The
reaction mixture was stirred at –55 °C for 30 min. Then cooling
was terminated. The reaction mixture was allowed to warm to
∼20 °C, stirred for 1 h, acidified with 20% HCl to рH ∼2, and
stirred for 10 h. Then volatile components were concentrated
under reduced pressure to 15—20 mL. Dichloromethane (80 mL)
was added to the residue. The reaction mixture was washed with
water (2×30 mL), dried over MgSO4, and filtered through a
SiO2 layer. The solvent was evaporated. The product was puriꢀ
fied by preparative chromatography (CHCl3—pentane, 1 : 1, as
the eluent). The oily product was obtained in a yield of 1.68 g
1
(95%). H NMR (CDCl3), δ: 2.25 (s, 6 H, Me + Me); 3.55 (s,
2 H, CH2). 13C NMR (CDCl3), δ: 201.6 (C(5)); 151.4, 149.2,
37.2 (C(4)); 29.5 (C(6)); 7.8 (C(1)).
1ꢀ(4ꢀMethylfurazanꢀ3ꢀyl)acetone oxime was synthesized
analogously to compound 9 from compound 1 (2 g, 0.02 mol)
(instead of acidification, the residue was dissolved in MeOH
(30 mL) followed by treatment with a solution of NH2OH•HCl
(1.39 g, 0.02 mol) in MeOH (20 mL)). The resulting mixture
was stirred for 3 h and filtered through a layer of silica gel. The
filtrate was concentrated and the residue was recrystallized from
PriOH. The product was obtained in a yield of 2 g (64%), m.p.
87—88 °C (cf. lit. data9: m.p. 88 °C).
20
(52%), nD 1.491; Rf = 0.60. Found (%): C, 46.20; H, 3.89;
N, 26.84. C8H8N4O3 (208.18). Calculated (%): C, 46.16;
H, 3.87; N, 26.91. MS, m/z: 208 [M+], 180, 151, 137, 125, 110,
97. IR, ν/cm–1: 2970, 2940, 1740, 1470, 1400, 1335, 1225, 1050,
920, 900. 1H NMR (CDCl3), δ: 2.32 and 2.54 (both s, 3 H each,
Me); 4.62 (s, 2 H, CH2). 13C NMR (CDCl3), δ: 185.8 (C(5));
150.5 (C(2)); 150.4 (C(6)); 149.7 (C(7)): 147.1 (C(3)); 34.6
(C(4)); 8.2, 7.3.
3ꢀMethylꢀ4ꢀ(tetrahydrofuranꢀ2ꢀylidenemethyl)furazan (8).
Analogously to the synthesis of compound 5, a solution of comꢀ
pound 1 (2.2 g, 0.0224 mol) in anhydrous THF (100 mL)
was lithiated with a solution of BuLi (1.44 g, 0.0224 mol,
0.043 g mL–1) in pentane. The brightꢀyellow reaction mixture
was stirred at –55 °C for 20 min, after which a solution of
γꢀbutyrolactone (2.0 g, 0.023 mol) in anhydrous THF (15 mL)
was rapidly added. After 30 min, cooling was terminated. The
reaction mixture was allowed to warm to ∼20 °C, stirred for 1 h,
1ꢀ(2ꢀFuryl)ꢀ2ꢀ(4ꢀmethylfurazanꢀ3ꢀyl)ethanol (10a). Analoꢀ
gously to the synthesis of compound 5, a solution of diꢀ
methylfurazan 1 (2.14 g, 0.0218 mol) in anhydrous THF
(100 mL) was lithiated with a solution of BuLi (1.4 g, 0.0218 mol,
0.064 g mL–1) in pentane. The brightꢀyellow reaction mixture
was stirred at –55 °C for 20 min, after which a solution of freshly
distilled furfurol (2.1 g, 0.0218 mol) in anhydrous THF (30 mL)
was rapidly added. The reaction mixture was stirred at –55 °C
for 30 min. Then the mixture was allowed to spontaneously
warm to ∼20 °C, stirred for 1 h, neutralized with a saturated
aqueous NH4Cl solution (10 mL), and concentrated under reꢀ
duced pressure to 25—30 mL. The residue was treated with ether
(150 mL) and washed with water (3×30 mL). The extract was
dried over MgSO4 and filtered through a layer of a mixture of
silica gel with NaHSO3 (100 : 1). The solvent was removed
under reduced pressure. The oily product with 95% purity was

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Sheremetev et al.
obtained in a yield of 2.7 g (64%). Found (%): C, 55.75; H, 5.18;
N, 14.31. C9H10N2O3 (194.19). Calculated (%): C, 55.67;
H, 5.19; N, 14.43. MS, m/z: 194 [M+], 176 [M – H2O]+, 164
[M – NO]+, 146 [M – NO – H2O]+.
tract was dried over CaCl2, the solvent was removed, and the
residue was passed through a short column with SiO2 (CHCl3 as
the eluent). Oily product 15 was obtained in a yield of 0.97 g
20
(94%), nD 1.499, Rf 0.50 (CH2Cl2). Found (%): C, 73.79;
Attempts to purify the product on a chromatographic plate
(SiO2 40/100 µm, CHCl3—hexane, 2 : 1, as the eluent) led to its
substantial decomposition (apparently, the product was dehyꢀ
drated followed by the transformation of the resulting vinyl inꢀ
termediate) to form a mixture of compounds.
2ꢀ(4ꢀMethylfurazanꢀ3ꢀyl)ꢀ1ꢀ(2ꢀthienyl)ethanol (10b) was
prepared analogously to compound 10а. Thienylethanol 10b
was obtained as an amorphous creamꢀcolored compound in
72% yield, m.p. 127—128 °C. Found (%): C, 51.47; H, 4.81;
N, 13.31, S, 15.18. C9H10N2O2S (210.25). Calculated (%):
C, 51.41; H, 4.79; N, 13.32; S, 15.25. MS, m/z: 210 [M+], 192
[M – H2O]+, 180 [M – NO]+, 162 [M – NO – H2O]+. 1H NMR
(CDCl3), δ: 2.27 (s, 3 H, Me); 3.20 (d, 2 H, CH2, J = 6.6 Hz);
5.42 (t, 1 H, C(5)H, J = 6.6 Hz); 6.98 (m, 2 H, C(7)H, C(8)H);
7.29 (br.s, 1 H, C(9)H). 13C NMR (CDCl3), δ: 151.7, 151.4
(C(2), C(3)); 146.3 (C(6)); 126.9, 125.1, 124.4 (C(7)—C(9));
68.8 (C(5)); 33.3 (C(4)); 6.0 (C(1)).
1ꢀHydroxyiminоꢀ1ꢀ(4ꢀmethylfurazanꢀ3ꢀyl)acetone (12). A soꢀ
lution of NaNO2 (1.52 g, 0.022 mol) in water (5 mL) was slowly
added dropwise with vigorous stirring to a solution of compound
9 (2.8 g, 0.02 mol) in 80% AcOH (5 mL) cooled to 0 °C. The
reaction mixture was stirred at 0 °C for 1 h and then a solution of
NaOH (2.5 g, 0.0625 mol) in water (20 mL) was added. The
reaction mixture was stirred for 2 h and then kept in a refrigeraꢀ
tor (+4 °C) for 16 h. The product was filtered off and recrystalꢀ
lized from benzene. Compound 12 was obtained as colorless
crystals in a yield of 1.95 g (57%), m.p. 151—153 °C (cf. lit.
data9: m.p. 153 °C).
1ꢀMethylꢀ2ꢀ(4ꢀmethylfurazanꢀ3ꢀyl)glyoxime (13). A solution
of NH2OH in MeOH (20 mL) (was prepared from NH2OH•HCl
(1.39 g, 0.02 mol) and sodium (0.46 g, 0.02 mol), NaCl being
filtered off) was added to a solution of compound 12 (1.69 g,
0.01 mol) in MeOH (15 mL). The resulting solution was stirred
at 50—55 °C for 2 h, concentrated to 1/3 of the initial volume,
cooled to 0 °C, and kept for 8 h. The product was filtered off and
recrystallized from benzene. The crystalline product was obꢀ
tained in a yield of 1.63 g (88%), m.p. 171.5—172.5 °C (cf. lit.
data9: m.p. 172 °C). MS, m/z: 184 [M+], 167 [M+ – OH],
154 [M+ – NO], 148, 136, 125, 109, 101, 95, 84. 1H NMR
(DMSOꢀd6), δ: 2.18 (s, 3 H, C(1)H3); 2.28 (s, 3 H, C(6)H3);
11.9 (br.s, 1 H, =N—OH); 12.7 (br.s, 1 H, =N—OH). 13C NMR
(DMSOꢀd6), δ: 152.8 (C(3)); 151.3 (C(5)); 148.3 (C(4)): 143.6
(C(2)); 9.7 (C(1)); 7.9 (C(6)).
H, 8.30; N, 11.36. C15H20N2O (244.34). Calculated (%):
C, 73.74; H, 8.25; N, 11.47. MS, m/z: 244 [M+], 188, 187, 171,
130, 123, 109, 105, 84. 1H NMR (CDCl3), δ: 0.95 (t, 3 H, CH3,
J = 6.9 Hz); 1.30—1.50 (m, 4 H, C(11)H2, C(12)H2); 1.68 (m,
2 H, C(10)H2); 2.54 (t, 2 H, C(9)H2, J = 6.6 Hz); 3.00—3.20
(m, 4 H, C(5)H2, C(6)H2); 7.20—7.50 (m, 5 H, Ph). 13C NMR
(CDCl3), δ: 154.2 (C(8)); 153.5 (C(7)); 139.9 (C(4)); 128.5,
128.3 (C(2), C(3)); 126.4 (C(1)); 33.7 (C(5)); 31.1 (C(11));
26.8 (C(10)); 25.2 (C(6)); 22.7 (C(9)); 22.1 (C(12)); 13.8
(C(13)). IR, ν/cm–1: 3064, 3032, 2928, 2888, 2864, 1604,
1592, 1580, 1536, 1496, 1484, 1456, 1408, 1376, 1176, 1080,
1016, 888.
3,4ꢀBis(2ꢀphenylethyl)furazan (16) was prepared analogously
to compound 15 from BnCl (0.63 g, 5 mmol). Chromatographic
separation (CH2Cl2—pentane, 2 : 1, as the eluent) afforded the
20
product as a colorless oil in a yield of 0.88 g (74%), nD 1.565.
Found (%): C, 77.70; H, 6.55; N, 10.01. C18H18N2O (278.35).
Calculated (%): C, 77.67; H, 6.52; N, 10.06. MS, m/z: 278 [M+],
261, 248, 201, 187, 172, 157, 143, 130, 105, 91. 1H NMR
(CDCl3), δ: 2.80 (t, 2 H, C(6)H2, J = 7.4 Hz); 3.10 (t, 2 H,
C(5)H2, J = 7.4 Hz); 7.10—7.40 (m, 5 H, Ph). 13C NMR
(CDCl3), δ: 153.6 (C(7)); 139.6 (C(4)); 128.2, 128.5 (C(2),
C(3)); 126.5 (C(1)); 33.7 (C(5)); 24.9 (C(6)). IR, ν/cm–1: 3060,
3038, 2940, 2875, 1605, 1500, 1465, 1084, 1038, 890.
4ꢀ(2ꢀPhenylethyl)ꢀ3ꢀ[2ꢀ(pꢀtolyl)ethyl]furazan (17) was preꢀ
pared analogously to compound 16 in 87% yield. Oil, nD20 1.558.
MS, m/z: 292 [M+]. Found (%): C, 78.08; H, 6.91; N, 9.52.
C19H20N2O (292.38). Calculated (%): C, 78.05; H, 6.89; N, 9.58.
1H NMR (CDCl3), δ: 2.40 (s, 3 H, Me); 2.85 (m, 4 H, C(6)H2,
C(9)H2); 3.05 (m, 4 H, C(5)H2, C(10)H2); 7.05—7.50 (m, 9 H,
Ar). 13C NMR (CDCl3), δ: 153.6 (C(7), C(8)): 139.6 (C(4));
136.7 (C(11)); 135.9 (C(14)); 129.1 (C(13)); 127.9—128.7 (C(2),
C(3), C(12), C(13)); 126.4 (C(1)); 33.2, 33.5 (C(5), C(10));
24.8, 25.0 (C(6), C(9)); 20.8 (C(15)). IR, ν/cm–1: 3028, 2930,
2867, 1605, 1580, 1518, 1500, 1457, 1187, 1114, 1083, 1028,
895, 818.
4ꢀ[2ꢀ(2ꢀChlorophenyl)ethyl]ꢀ3ꢀ(2ꢀphenylethyl)furazan (18)
was prepared analogously to compound 16 in 76% yield. Oil,
nD20 1.569. Found (%): C, 69.18; H, 5.51; N, 8.88. C18H17ClN2O
(312.80). Calculated (%): C, 69.12; H, 5.48; N, 8.96. MS, m/z:
313, 311 [M+], 270, 187, 130, 125, 105, 91. 1H NMR (CDCl3),
δ: 2.80—3.30 (m, 8 H, CH2); 7.00—7.50 (m, 9 H, Ar). 13C NMR
(CDCl3), δ: 153.6, 153.4 (C(7), C(8)); 139.7 (C(4)); 137.2
(C(11)); 133.6 (C(16)), 130.6, 129.5, 128.5, 128.4, 128.2, 126.9,
126.4 (Ar); 33.7, 31.8 (C(5), C(10)); 24.9, 22.9 (C(6), C(9)).
IR, ν/cm–1: 3066, 3037, 2940, 2400, 1605, 1574, 1495, 1478,
1450, 1170, 1128, 1083, 1060, 900, 765, 710.
3ꢀPentylꢀ4ꢀ(2ꢀphenylethyl)furazan (15). Analogously to the
synthesis of compound 5, a solution of compound 5 (0.8 g,
4.25 mmol) in anhydrous THF (150 mL) was placed in a 250ꢀmL
flask and lithiated with a solution of BuLi (0.272 g, 4.25 mmol,
0.051 g mL–1) in pentane. The brightꢀyellow reaction mixture
was stirred at –55 °C for 20 min, after which a solution of BunCl
(0.4 g, 4.3 mmol) in anhydrous THF (10 mL) was rapidly added
at the same temperature. The reaction mixture was stirred for
30 min. Then cooling was terminated. The reaction mixture was
allowed to warm to ∼20 °C, stirred for 1 h, and neutralized with
a saturated aqueous NH4Cl solution (10 mL). The solvent was
removed under reduced pressure. The residue was treated with
water (60 mL) and extracted with CHCl3 (2×50 mL). The exꢀ
3ꢀ[2ꢀ(2,4ꢀDichlorophenyl)ethyl]ꢀ4ꢀ(2ꢀphenylethyl)furazan
(19) was prepared analogously to compound 16 in 24% yield.
20
Oil, nD 1.577. Found (%): C, 62.31; H, 4.61; N, 8.06.
C18H16Cl2N2O (347.24). Calculated (%): C, 62.26; H, 4.64;
N, 8.07. MS, m/z: 347, 345 [M+], 331, 329, 313, 311, 293, 280,
266, 187, 172, 159, 130, 115, 105, 91, 77. 1H NMR (CDCl3), δ:
2.80 (t, 2 H, C(9)H2, J = 7.2 Hz); 2.91 (t, 2 H, C(6)H2, J =
7.2 Hz); 3.06 (t, 2 H, C(10)H2, J = 7.3 Hz); 3.09 (t, 2 H,
C(5)H2, J = 7.3 Hz); 7.09 (d, 1 H, H(12), J = 7.2 Hz); 7.17 (m,

Furazanylethanes
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 3, March, 2003
687
3 H, H(3), H(13)); 7.25 (t, 1 H, H(1), J = 7.6 Hz); 7.30 (t, 2 H,
H(2), J = 7.1 Hz); 7.39 (d, 1 H, H(15), J = 2.1 Hz). 13C NMR
(CDCl3), δ: 153.4 (C(7)); 153.0 (C(8)); 139.6 (C(4)); 135.8
(C(11)); 134.2 (C(16)); 133.0 (C(14)); 131.4 (C(12)); 129.3
(C(15)); 128.5 (C(2)); 128.3 (C(3)); 127.2 (C(13)); 126.5 (C(1));
lated (%): C, 63.37; H, 5.67; N, 19.71. MS, m/z: 284 [M]+, 254
[M – NO]+, 224 [M – 2 NO]+, 188, 187, 130, 117, 103, 98, 91.
IR, ν/cm–1: 3065, 3037, 2940, 1605, 1580, 1500, 1450, 1385,
1182, 1085, 1046, 965, 900.
B. Compound 22 was prepared analogously by lithiation of
compound 5 followed by treatment with 4ꢀ(chloromethyl)ꢀ3ꢀ
methylfurazan. The product was obtained in 66% yield.
33.7 (C(5)); 30.9 (C(10)); 24.9 (C(6)); 22.6 (C(9)). IR, ν/cm–1
:
3060, 3030, 2938, 2867, 1590, 1560, 1500, 1478, 1458, 1390,
1108, 1084, 1057, 1030, 847, 837, 815, 780, 705.
1,2ꢀBis[4ꢀ(2ꢀphenylethyl)furazanꢀ3ꢀyl]ethane (23). A soluꢀ
tion of compound 5 (2.82 g, 0.015 mol) in anhydrous THF
(150 mL) was placed in a 250ꢀmL threeꢀneck flask equipped
with a thermometer and two dropping funnels with pressureꢀ
equalization arms and then a solution of BuLi (0.96 g, 0.015 mol,
0.024 g mL–1) in pentane was added dropwise with stirring at
–55 °C under a static atmosphere of argon. After 20 min, anꢀ
hydrous CuCl (2.025 g, 0.016 mol) was rapidly added and the
reaction mixture was stirred at –55 °C for 30 min. Then cooling
was terminated. The reaction mixture was allowed to warm to
20 °C and stirred for 10 h. The solvent was evaporated and the
residue was diluted with CH2Cl2 (150 mL). The resulting soluꢀ
tion was washed with 10% HCl and water. The organic solution
was dried over MgSO4 and filtered through a layer of silica gel,
after which the solvent was evaporated. The product was recrysꢀ
tallized from CHCl3. Colorless crystals of the product were obꢀ
tained in a yield of 1.2 g (43%), m.p. 75—76 °C. Found (%):
C, 70.61; H, 6.04; N, 14.87. C22H22N4O2 (374.44). Calcuꢀ
lated (%): C, 70.57; H, 5.92; N, 14.96. MS, m/z: 374 [M]+, 344
[M – NO]+, 297, 268, 226, 212, 191, 130, 105, 91, 77. IR,
ν/cm–1: 3075, 3037, 2950, 2938, 1605, 1585, 1496, 1455, 1445,
1295, 1170, 1080, 1040, 1030, 1020, 890. 1H NMR (CDCl3), δ:
2.85 (s, 4 H, C(9)H2); 3.00—3.20 (m, 8 H, C(5)H2, C(6)H2);
7.15—7.40 (m, 10 H, Ph). 13C NMR (CDCl3), δ: 153.4 (C(7));
152.8 (C(8)); 139.6 (C(4)); 128.5 (C(2)); 128.3 (C(3)); 126.5
(C(1)); 33.7 (C(5)); 25.0 (C(6)); 20.6 (C(9)).
3ꢀ[2ꢀ(1ꢀNaphthyl)ethyl]ꢀ4ꢀ(2ꢀphenylethyl)furazan (20) was
prepared analogously to compound 16 in 39% yield as colorless
crystals, m.p. 53—54 °C (from hexane). Found (%): C, 80.52;
H, 6.20; N, 8.47. C22H20N2O (328.41). Calculated (%): C, 80.46;
H, 6.14; N, 8.53. MS, m/z: 328 [M+], 311, 294, 282, 270, 254,
1
237, 221, 207, 180, 165, 153, 141, 115, 105, 91, 77. H NMR
(CDCl3), δ: 2.70 (t, 2 H, C(6)H2, J = 5.9 Hz); 3.00 (m, 4 H,
C(5)H2, C(9)H2); 3.55 (t, 2 H, C(10)H2, J = 6.2 Hz); 7.10 (d,
2 H, H(3), J = 5.6 Hz); 7.35 (m, 4 H, H(1), H(2), H(14)); 7.50
(t, 1 H, H(13), J = 5.2 Hz); 7.65 (m, 2 H, H(17), H(18)); 7.87
(d, 1 H, H(12), J = 4.4 Hz); 7.95 (d, 1 H, H(16), J = 5.4 Hz);
8.10 (d, 1 H, H(19), J = 5.2 Hz). 13C NMR (CDCl3), δ: 153.8
(C(8)); 153.6 (C(7)); 139.6 (C(4)); 135.7 (C(11)); 133.7 (C(15));
131.2 (C(20)); 128.8 (C(16)); 128.4 (C(2)); 128.1 (C(3));
127.3 (C(12)); 126.3 (C(14)); 126.2 (C(1)); 126.1 (C(18));
125.6 (C(17)); 125.4 (C(13)); 123.0 (C(19)); 33.5 (C(5)); 30.9
(C(10)); 24.7 (C(6)); 24.0 (C(9)). IR, ν/cm–1: 3030, 2940, 1600,
1515, 1495, 1455, 1445, 1400, 1170, 1020, 890, 810, 795, 787,
765, 710.
3ꢀ[2ꢀHydroxyꢀ2ꢀ(2ꢀfuryl)ethyl]ꢀ4ꢀ(2ꢀphenylethyl)furazan
(21) was prepared analogously to compound 10 from compound
5 as an oil in a yield of 2.0 g (35%), nD20 1.57, Rf 0.50 (CH2Cl2).
Found (%): C, 67.66; H, 5.69; N, 9.79. C16H16N2O3 (284.31).
Calculated (%): C, 67.59; H, 5.67; N, 9.85. MS, m/z: 284 [M]+,
266 [M – H2O]+, 254 [M – NO]+, 236 [M – NO – H2O]+.
1H NMR (DMSOꢀd6), δ: 2.90—3.00 (m, 4 H, C(5)H2, C(6)H2);
3.05 (d, 2 H, C(9)H2, J = 6.6 Hz); 4.70 (br.s, 1 H, OH); 4.95 (t,
1 H, C(10)H, J = 6.6 Hz); 6.20—6.30 (m, 2 H, C(12)H,
C(13)H); 7.10—7.30 (m, 5 H, Ph); 7.40 (d, 1 H, C(14)H, J =
2.4 Hz). 13C NMR (DMSOꢀd6), δ: 157.0 (C(7)); 156.2 (C(8));
153.3 (C(11)); 143.6 (C(14)); 141.9 (C(4)); 130.4, 129.8 (C(2),
C(3)); 127.7 (C(1)); 111.6 (C(13)); 107.7 (C(12)); 67.2 (C(10));
35.0 (C(5)); 30.7 (C(9)); 28.2 (C(6)). IR, ν/cm–1: 3432, 3032,
2936, 2864, 2528, 1604, 1496, 1456, 1408, 1220, 1176, 1148,
1012, 960.
1,2ꢀBis[4ꢀ(3ꢀmethylbutꢀ3ꢀenꢀ1ꢀyl)furazanꢀ3ꢀyl]ethane (24)
was prepared analogously to compound 23 from 3ꢀmethylꢀ4ꢀ(3ꢀ
methylbutꢀ3ꢀenꢀ1ꢀyl)furazan.1 The yield was 83%. Colorless
crystalline compound, m.p. 74—75 °C. Found (%): C, 63.61;
H, 7.41; N, 18.48. C16H22N4O2 (302.38). Calculated (%):
C, 63.56; H, 7.33; N, 18.53. MS, m/z: 301 [M – H]+, 285 [M –
H – CH4]+, 272 [M – NO]+, 240, 229, 190, 174. IR, ν/cm–1
:
3084, 2995, 2980, 2950, 2920, 2900, 1650, 1590, 1500, 1450,
1377, 1322, 1220, 1250, 1173, 1018, 894, 888. 1H NMR (CDCl3),
δ: 1.80 (s, 3 H, CH3); 2.40 (br.t, 2 H, C(4)H2, J = 7.6—8.0 Hz);
2.90 (t, 2 H, C(5)H2, J = 7.6 Hz); 3.20 (s, 2 H, C(8)H2);
4.70—4.80 (d, 2 H, CH, J = 16.3 Hz). 13C NMR (CDCl3), δ:
153.7 (C(6)); 152.7 (C(7)); 143.2 (C(2)); 111.3 (C(1)); 34.9
(C(4)); 22.2 (C(3)); 21.4 (C(5)); 21.0 (C(8)).
1ꢀ(4ꢀMethylfurazanꢀ3ꢀyl)ꢀ2ꢀ[4ꢀ(2ꢀphenylethyl)furazanꢀ3ꢀ
yl]ethane (22). A. Analogously to the synthesis of compound 5, a
solution of compound 6 (0.65 g, 3.35 mmol) in anhydrous THF
(50 mL) was placed in a 250ꢀmL flask and lithiated with a
solution of BuLi (0.214 g, 3.35 mmol, 0.042 g mL–1) in pentane.
The brightꢀred reaction mixture was stirred at –55 °C for 20 min,
after which a solution of BnCl (0.42 g, 3.35 mmol) in anhydrous
THF (5 mL) was rapidly added. The reaction mixture was stirred
at –55 °C for 30 min, allowed to spontaneously warm to ∼20 °C,
and stirred for 10 h. The solvent was evaporated and the residue
was diluted with CH2Cl2 (100 mL). The resulting solution was
washed with 10% HCl and water. The organic layer was dried
over MgSO4, the solvent was evaporated, and the residue was
fractionated on a chromatographic plate (SiO2, 40/100 µm,
CHCl3—pentane, 1 : 1, as the eluent). The oily product was
References
1. A. Yu. Sizov and A. B. Sheremetev, Izv. Akad. Nauk, Ser.
Khim., 1992, 365 [Russ. Chem. Bull., 1992, 41, 281 (Engl.
Transl.)].
2. A. B. Sheremetev, E. A. Ivanova, and D. E. Dmitriev, Tez.
dokl. konf. "Organicheskii sintez i kombinatornaya khimiya"
[Abstrs. of Papers, Conf. "Organic Synthesis and Combinatorial
Chemistry] (March 4—7, 1999, Suzdal´), Moscow, 1999, Pꢀ64
(in Russian).
20
isolated in a yield of 0.63 g (68%), nD 1.530. Found (%):
C, 63.36; H, 5.73; N, 19.67. C15H16N4O2 (284.32). Calcuꢀ
3. B. Iddon, Heterocycles, 1994, 37, 1263.

688
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 3, March, 2003
Sheremetev et al.
4. B. Iddon, Heterocycles, 1995, 38, 263.
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Received October 23, 2002;
in revised form December 18, 2002