A new convenient four-component synthesis of 6-amino-2H,4H-pyrano[2,3-c] pyrazole-5-carbonitriles and one-pot synthesis of 6′-amino-5′-cyano- 1,2-dihydrospiro- [(3H)-indole-3,4′-(4′H)-pyrano[2,3-c]pyrazol]-2- ones

Article abstract of DOI:10.1007/s11172-009-0328-4

A new convenient method for the synthesis of 6-amino-2H,4H-pyrano[2,3-c] pyrazole-5-carbonitriles, namely, four-component condensation of carbonyl compounds (aromatic aldehydes, heterocyclic ketones), malononitrile, ss-keto esters, and hydrazine hydrate in ethanol in the presence of triethylamine as a catalyst, which occurs selectively, is developed. One-pot two-step modification of this method is proposed for the synthesis of spiro[(3H)-indole-3,4′-(4′H)-pyrano[2,3-c]pyrazol]-2-ones.

Full text of DOI:10.1007/s11172-009-0328-4

Russian Chemical Bulletin, International Edition, Vol. 58, No. 11, pp. 2362—2368, November, 2009
2362
A new convenient fourꢀcomponent synthesis of
6ꢀaminoꢀ2H,4Hꢀpyrano[2,3ꢀс]pyrazoleꢀ5ꢀcarbonitriles
and oneꢀpot synthesis of 6´ꢀaminoꢀ5´ꢀcyanoꢀ1,2ꢀdihydrospiroꢀ
[(3H)ꢀindoleꢀ3,4´ꢀ(4´H)ꢀpyrano[2,3ꢀс]pyrazol]ꢀ2ꢀones
Yu. M. Litvinov, L. A. Rodinovskaya, and A. M. Shestopalov
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences,
47 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 5328. Eꢀmail: amsh@ioc.ac.ru
A new convenient method for the synthesis of 6ꢀaminoꢀ2H,4Hꢀpyrano[2,3ꢀс]pyrazoleꢀ
5ꢀcarbonitriles, namely, fourꢀcomponent condensation of carbonyl compounds (aromatic
aldehydes, heterocyclic ketones), malononitrile, βꢀketo esters, and hydrazine hydrate in ethanol
in the presence of triethylamine as a catalyst, which occurs selectively, is developed. Oneꢀpot
twoꢀstep modification of this method is proposed for the synthesis of spiro[(3H)ꢀindoleꢀ3,4´ꢀ
(4´H)ꢀpyrano[2,3ꢀс]pyrazol]ꢀ2ꢀones.
Key words: fourꢀcomponent reaction, oneꢀpot modification, 6ꢀaminoꢀ2H,4Hꢀpyranoꢀ
[2,3ꢀс]pyrazoleꢀ5ꢀcarbonitriles, 2´ꢀaminoꢀ5´ꢀcyanospiro[(3H)ꢀindoleꢀ3,4´ꢀ(4´H)ꢀpyran]ꢀ
2ꢀones, aromatic aldehydes, piperidinꢀ4ꢀones, isatins, malononitrile, βꢀketo esters, hydrazine
hydrate, triethylamine.
6ꢀAminopyrano[2,3ꢀс]pyrazoleꢀ5ꢀcarbonitriles are the
All four components were dissolved in ethanol and the
reaction was carried out by refluxing the reaction mixture
for 15 min in the presence of triethylamine as the basic
catalyst (method A). In principle, all four components
may be varied in this multicomponent condensation:
aromatic aldehydes 1a—k, malononitrile 2, βꢀketo esters
3a—d, hydrazine hydrate 4. Thus, the use of aromatic
aldehydes with electronꢀwithdrawing (1b—e) or electronꢀ
donating substituents (1f—i), and heterocyclic aldeꢀ
hydes 1j,k results in products 5a—l in 56—72% yields
(Scheme 1). Variations of βꢀketo esters 3a—d are also
possible. However, ethyl pivaloylacetate (R2 = But) did
not give pyrano[2,3ꢀc]pyrazole under analogous condiꢀ
tions even when the duration of the reaction was increased
(up to 30—60 min), apparently, for steric reasons. Possibly,
βꢀketo esters 3 and hydrazine hydrate 4 give pyrazolinones,18
and aromatic aldehydes 1 undergo the Knoevenagel reacꢀ
tion with malononitrile 2 to give arylidenemalononitriles.
Then the reaction of arylidenemalononitriles with pyrazolꢀ
inones leads to pyranopyrazoles 5.3,4
subject of extensive investigations.1–12 The first example
of the synthesis of these compounds was based on the
reaction of tetracyanoethylene with 3ꢀmethylpyrazolinꢀ
5ꢀone resulting in 6ꢀaminoꢀ2H,4Hꢀpyrano[2,3ꢀс]pyrazoleꢀ
4,4,5ꢀtricarbonitriles.1 4ꢀArylꢀ1—6 and 4ꢀalkyl substituted
pyranopyrazoles,7,8 as well as heterocycles that contain
spiroꢀfused rings8—14 are among the wellꢀknown comꢀ
pounds of this class. 6ꢀAminoꢀ3ꢀmethylꢀ1,4ꢀdiphenylꢀ
pyrano[2,3ꢀс]pyrazoleꢀ5ꢀcarbonitrile was used in the synꢀ
thesis of annulated heterocycles.15 Some 6ꢀaminopyranoꢀ
[2,3ꢀс]pyrazoleꢀ5ꢀcarbonitriles demonstrate analgesic
activity;16 they were tested as potential inhibitors of
human kinase Chk1 (in vitro and computer simulation).17
Threeꢀcomponent condensation of aromatic aldehydes,
malononitrile, and pyrazolinꢀ5ꢀones2,3,5,7,8,10—12 or stepꢀ
byꢀstep assembly methods with the isolation of arylideneꢀ
malononitriles3,4 or 3ꢀalkylꢀ4ꢀarylidenepyrazolinꢀ5ꢀones6
are the standard methods for the synthesis of these hetꢀ
erocycles. Pyrano[2,3ꢀс]pyrazoles are the only reaction
products regardless of the order of addition of the reacꢀ
tants and the steps. Pyrazolinꢀ5ꢀones, in turn, are obtained
from βꢀketo esters and hydrazine hydrate.18 Recently,19,20
we have developed a fourꢀcomponent procedure for the
synthesis of 3ꢀalkylꢀ6ꢀaminoꢀ4ꢀarylpyrano[2,3ꢀс]pyrꢀ
azoles based on the reaction of aromatic aldehydes,
malononitrile, βꢀketo esters, and hydrazine hydrate in
ethanol in the presence of triethylamine.
Later, a report21 on fourꢀcomponent synthesis of
6ꢀaminoꢀ4ꢀarylꢀ3ꢀmethylꢀ4Нꢀpyrazolo[3,4ꢀb]pyrans in
water has been published.
We employed cyclic ketones: Nꢀsubstituted piperidinꢀ
4ꢀones 6a,b and isatins 7a—c in the fourꢀcomponent
reaction to expand the synthetic potential of this reaction
and to investigate the possibility of the synthesis of spiroꢀ
fused heterocyles. It was found that these ketones have
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2288—2293, November, 2009.
1066ꢀ5285/09/5811ꢀ2362 © 2009 Springer Science+Business Media, Inc.

Fourꢀcomponent synthesis of pyranopyrazoles
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 11, November, 2009 2363
Scheme 1
Scheme 2
15 min
15 min
1: R1 = Ph (a), 2,6ꢀF2C6H3 (b), 2,6ꢀCl C6H3 (c),
2
4ꢀ(CF3)C6H4 (d), (MeOOC)C6H4 (e), 4ꢀMe2NC6H4 (f),
3ꢀHOC6H4 (g), 2,5ꢀ(MeO)2C6H3 (h), 3ꢀ(MeO)ꢀ4ꢀ(PhCH2O)C6H3
(i), 3ꢀC4H3O (j), 2ꢀC4H3S (k)
6: R1 = COMe (a), COOEt (b)
3: R2 = Ph (a), Me (b), Prn (c), CH2OMe (d)
3: R2 = Me (b), Prn (c), CH2OMe (d)
8: R1 = COMe, R2 = Prn (a); R1 = COMe, R2 = CH2OMe (b);
Compound
R1
R2
R
1 = COOEt, R2 = Me (c)
5a
5b
5c
5d
5e
5f
5g
5h
5i
Ph
Ph
Me
Me
Me
Me
Prn
CH2OMe
Me
Me
2,6ꢀF2C6H3
2,6ꢀCl2C6H3
4ꢀ(CF3)C6H4
4ꢀ(MeOOC)C6H4
4ꢀMe2NC6H4
3ꢀHOC6H4
2,5ꢀ(MeO)2C6H3
3ꢀ(MeO)ꢀ4ꢀ(PhCH2O)C6H3
3ꢀC4H3O
corresponding βꢀketo ester 3b,c with hydrazine hydrate
was carried out in refluxing ethanol (5 min). Then, to
pyrazolinones 11a,b that formed, isatin 7a—c, malonoꢀ
nitrile 2, and triethylamine were added, and reflux was
continued for 5 min. Compounds 12a—d were obtained
under these conditions in 76—85% yields (Scheme 3).
Possibly, in this case isatins 7a—c react with malonoꢀ
nitrile 2 to form unsaturated nitriles of type 10, which add
pyrazolinone 11 with the closure of the pyran ring. It is
important to note that in the case of 12a the yield of the
product was higher than in previous studies where this
compound was obtained from unsaturated nitrile 10 and
5ꢀmethylꢀ2,4ꢀdihydroꢀ3Hꢀpyrazoleꢀ3ꢀone 11a (54%)13 or
isatin 7a, malononitrile 2, and pyrazolinone 11a (74%).14
The developed fourꢀcomponent method for synthesis
of pyranopyrazoles consisted of reaction in ethanol in
the presence of a base, triethylamine. These conditions
impose one more limitation on the variation of the startꢀ
ing components. The replacement of hydrazine hydrate 4
by phenylhydrazine 13 resulted in benzaldehyde phenylꢀ
hydrazone 14 (see Ref. 22) as a single crystalline reaction
product in the fourꢀcomponent condensation with benzꢀ
aldehyde 1a, malononitrile 2, and ethyl acetoacetate 3b
regardless of the reaction duration (Scheme 4). Thus,
the fourꢀcomponent reaction gives an access only to
Nꢀunsubstituted pyrano[2,3ꢀc]pyrazoles under the condiꢀ
tions found.
5j
5k
5l
CH2OMe
Ph
Me
3ꢀC4H3O
2ꢀC4H3S
different reactivities under conditions of the fourꢀcompoꢀ
nent reaction with malononitrile 2, βꢀketo esters 3b—d,
and hydrazine hydrate 4. The reaction faces no difficulꢀ
ties in the case of piperidinꢀ4ꢀones 6a,b and leads to the
formation of spiroꢀfused pyrano[2,3ꢀс]pyrazoles 8a—c in
48—62% yields, the N—COMe and N—COOEt groups
remaining intact (method А) (Scheme 2).
In the case of isatin 7a, the reaction occurs with the
formation of stable isatin monohydrazone 9 despite simulꢀ
taneous addition of other reactants, i.e., malononitrile 2,
ethyl acetoacetate 3b, and hydrazine hydrate 4, regardless
of duration of heating (5—30 min). Product 9 was also
formed in the reaction of preformed 2ꢀ(2ꢀoxoꢀ1,2ꢀdiꢀ
hydroꢀ3Hꢀindoleꢀ3ꢀylidene)malononitrile 10 with ethyl
acetoacetate 3b and hydrazine hydrate 4. However,
having changed the order of mixing the reactants, we
developed a new oneꢀpot modification of the fourꢀcomꢀ
ponent reaction (method B). Initially, the reaction of the

2364
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 11, November, 2009
Litvinov et al.
Scheme 3
5—30 min
5—30 min
5 min
5 min
7a: R2 = H, R3 = H
12a: R1 = Me, R2 = H, R3 = H
12b: R1 = Me, R2 = H, R3 = 7ꢀMe
12c: R1 = Me, R2 = Prn, R3 = H
12d: R1 = Prn, R2 = H, R3 = 7ꢀMe
7b: R2 = H, R3 = 7ꢀMe
7c: R2 = Pr, R3 = H
11: R2 = Me (a), Prn (b)
Scheme 4
oxindole fragment (δ 10.51—10.60, br.s, 1 H). The presꢀ
ence of the signals of alkyl (5b—j,l, 8a—c, 12a—d) and
aryl (5a—l, 12a—d) substituents also corroborates the
structure of the obtained compounds. Melting points, data
1
from elemental analysis, IR and H NMR spectroscopy
for compounds 5, 8, and 12 are presented in Table 1.
Thus, in the present work it is shown that the conꢀ
venient oneꢀstep fourꢀcomponent synthesis of pyranoꢀ
[2,3ꢀс]pyrazoles can be used for the preparation of 4ꢀarylꢀ
substituted and spiroꢀfused heterocycles. When the
synthesis is carried out with isatins, it can be easily
transformed into a twoꢀstep oneꢀpot procedure.
5—30 min
The structures of all the obtained compounds 5, 8,
and 10 were established based on data from elemental
analysis, IR and H NMR spectroscopy. A characteristic
1
Experimental
feature of the IR spectra is the presence of a band of
stretching vibrations of the conjugated C≡N group in the
region 2204—2180 cm–1 and bands ν(NH), ν(NH2) at
3474—3168 cm–1, which is in accord with the spectral
data for the analogs that have previously been described.1—12
All the compounds are characterized be the presence
of signals of 6ꢀNH2 (δ 6.70—6.92, br.s, 2 H) and 2ꢀNH
The starting compounds were commercially available from
Lancster. All the synthesized compounds were characterized
by elemental analysis, IR and 1H NMR spectroscopy. 1H NMR
spectra were recorded on Bruker WMꢀ250 and Bruker AMꢀ300
instruments (250 and 300 MHz, respectively) in DMSOꢀd6,
Me4Si was used as the internal standard. IR spectra were
obtained on a Fourier spectrometer Specord Mꢀ82 in KBr pellets
(1 : 200 w/w). The control over the course of reactions and the
purity of the synthesized compounds were carried out by TLC
on Silufol UVꢀ254 plates, light petroleum—acetone (5 : 3),
visualization by iodine vapor. Melting points of the synthesized
1
(δ 12.04—12.87, br.s, 1 H) in the H NMR spectra. A
characterictic feature of the spectra of compounds 5a—l
is the presence of the signal for H(4) (δ 4.56—5.16, s,
1 H). 1H NMR spectra of compounds 12a—d are characꢀ
terized by the presence of the NH proton signal of the

Fourꢀcomponent synthesis of pyranopyrazoles
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 11, November, 2009 2365
Table 1. Yield, physical constants, and spectral characteristics of compounds 5, 8, and 12
Comꢀ
pound
Yield
(%)
M.p.
/°C
Found
Calculated
Molecular
formula
IR spectrum,
ν/cm–1
1H NMR, δ (J/Hz)
(%)
(ν(NH), ν(С≡N),
ν(C=O), δ(NH2),
ν(C=C))
C
H
N
5a
5b
65
275—276
272—273
72.70 4.33 17.69
72.60 4.49 17.82
C19H14N4O
3484, 3208, 3108, 4.98 (s, 1 H, H(4)); 6.88 (br.s, 2 H,
2204, 1636, 1588
NH2); 7.19 (m, 10 H, 2 Ph); 12.87
(br.s, 1 H, NH)
67
70
58.45 3.46 19.52
58.34 3.50 19.44
C14H10F2N4O 3398, 3360, 3280, 1.85 (s, 3 H, Me); 5.03 (s, 1 H,
3176, 2184, 1652, H(4)); 6.81 (br.s, 2 H, NH2); 7.04
1596
(m, 2 H, H(3´), H(5´)); 7.35 (m, 1 H,
H(4´)); 12.00 (br.s, 1 H, NH)
5c
5d
5e
249—250
244—245
240—242
52.44 3.08 17.36
52.36 3.14 17.44
C14H10Cl2N4O 3368, 3312, 3176, 1.80 (s, 3 H, Me); 5.16 (s, 1 H,
2192, 1648, 1600
H(4)); 6.94 (br.s, 2 H, NH2), 7.21
(t, 1 H, H(4´), J = 8.2); 7.35 (d, 2 H,
H(3´), H(5´), J = 8.3); 12.10 (br.s,
1 H, NH)
72
68
56.22 3.51 17.27
56.25 3.46 17.49
C15H11F3N4O 3480, 3232, 3120, 1.79 (s, 3 H, Me); 4.75 (s, 1 H,
2192, 1 640, 1596
H(4)); 6.96 (br.s, 2 H, NH2); 7.41
(d, 2 H, H(2´), H(6´), J = 7.7);
7.69 (d, 2 H, H(3´), H(5´), J = 7.7);
12.15 (br.s, 1 H, NH)
61.75 4.37 18.21
61.93 4.55 18.05
C16H14N4O3
3376, 3312, 3192, 1.79 (s, 3 H, Me); 3.85 (s, 3 H,
2184, 1724, 1648, COOCH3); 4.72 (s, 1 H, H(4));
1600
6.92 (br.s, 2 H, NH2); 7.34 (d, 2 H,
H(2´), H(6´), J = 8.2); 7.34 (d, 2 H,
H(3´), H(5´), J = 7.9); 12.12 (br.s,
1 H, NH)
5f
64
56
61
56
205—207
227—229
243—244
221—223
66.82 6.49 21.71
66.85 6.55 21.66
C18H21N5O
3488, 3248, 3112, 0.67 (t, 3 H, CH3CH2CH2, J = 7.4);
2200, 1632, 1596
1.14—1.35 (m, 2 H, CH3CH2CH2);
2.01—2.23 (m, 2 H, CH3CH2CH2);
4.45 (s, 1 H, H(4)); 6.65 (m, 4 H,
H(3´), H(5´), NH2); 6.95 (d, 2 H,
H(2´), H(6´), J = 8.8); 11.99 (br.s,
1 H, NH)
5g
5h
5i
60.18 4.85 18.74
60.40 4.73 18.78
C15H14N4O3
C16H16N4O3
C22H20N4O3
3456, 3296, 3192, 3.03 (s, 3 H, Me); 3.98 (AB system,
2192, 1632, 1592
2 H, Me, J = 13.2); 4.53 (s, 1 H,
H(4)); 6.55 (s, 1 H, H(2´)); 6.62 (d,
2 H, H(4´), H(6´), J = 7.4); 6.80
(br.s, 2 H, NH2); 7.10 (t, H(5´),
J = 7.7); 9.23 (s, 1 H, OH); 12.44
(br.s, 1 H, NH)
61.57 5.15 17.96
61.53 5.16 17.94
3320, 3168, 2200, 1.82 (s, 3 H, Me); 3.65 (s, 3 H,
1660, 1616, 1600
OMe); 3.73 (s, 3 H, OMe); 4.92
(s, 1 H, H(4)); 6.53 (d, 1 H, H(6´),
J = 2.8); 6.70 (br.s, 2 H, NH2);
6.77 (dd, 1 H, H(4´), J = 3.0,
J = 8.9); 6.93 (d, 1 H, H(3´),
J = 8.7); 11.95 (br.s, 1 H, NH)
67.76 5.23 14.65
68.03 5.19 14.42
3464, 3248, 3112, 1.84 (s, 3 H, Me); 3.73 (s, 3 H,
2184, 1644, 1596
OMe); 4.56 (s, 1 H, H(4)); 5.04 (s,
2 H, PhCH2O); 6.68 (d, 1 H, H(5´),
J = 7.9); 6.72 (br.s, 2 H, NH2); 6.80
(s, 1 H, H(2´)); 6.99 (d, 1 H, H(6´),
J = 7.9); 7.32—7.46 (m, 5 H, Ph);
12.01 (br.s, 1 H, NH)
(to be continued)

2366
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 11, November, 2009
Litvinov et al.
Table 1 (continued)
Comꢀ
pound
Yield
(%)
M.p.
/°C
Found
Calculated
Molecular
formula
IR spectrum,
ν/cm–1
1H NMR, δ (J/Hz)
(%)
(ν(NH), ν(С≡N),
ν(C=O), δ(NH2),
ν(C=C))
C
H
N
5j
62
233—235
228—230
57.54 4.24 20.62
57.35 4.44 20.58
C13H12N4O3
3408, 3296, 3192, 3.11 (s, 3 H, Me); 4.10 (AB system,
2200, 1632, 1600
2 H, Me, J = 12.9); 4.64 (s, 1 H,
H(4)); 6.23 (s, 1 H, H(4´)); 6.83
(br.s, 2 H, NH2); 7.56 (s, 2 H,
H(2´), H(5´)); 12.48 (br.s, 1 H, NH)
5k
65
67.19 3.82
67.10 3.97
18.62
18.41
C17H12N4O2 3488, 3128, 2200, 4.97 (s, 1 H, H(4)); 6.10 (s, 1 H,
1636, 1604
H(4´) C4H3O); 6.69 (br.s, 2 H,
NH2); 7.16—7.24 (m, 1 H, ArH);
7.32—7.40 (m, 4 H, ArH);
7.53—7.55 (m, 2 H, ArH);
12.70 (br.s, 1 H, NH)
5l
70
59
258—260
199—201
55.54 3.91
55.80 3.90
21.84
21.69
C12H10N4OS 3369, 3320, 3168, 1.92 (s, 3 H, Me); 4.99 (s, 1 H,
2192, 1648, 1592
H(4)); 6.95 (m, 3 H, ArH + NH2);
7.01 (m, 1 H, ArH); 7.37 (d, 1 H,
ArH, J = 5.3); 12.18 (br.s, 1 H, NH)
8a
60.78 6.42
(199—200)11 60.94 6.71
22.34
22.21
C16H21N5O2 3392, 3312, 3192, 0.88 (t, 3 H, CH3CH2CH2, J = 7.0);
2192, 1668, 1638
1.80—1.82 (m, 4 H); 1.87 (m, 2 H);
1.97 (m, 2 H) (MeCH2CH2 +
+ (CH2CH2)N); 2.02 (s, 3 H,
MeCO); 3.39 (m, 1 H); 3.73 (m,
2 H); 4.21 (m, 1 H, (CH2CH2)N);
6.81 (br.s, 2 H, NH2); 12.15 (br.s,
1 H, NH)
8b
62
175—176
56.53 5.91
21.79
22.07
C15H19N5O3 3392, 3317, 3200, 1.80—2.04 (m, 4 H, CH2CH2);
(176—177)11 56.77 6.03
2196, 1672, 1642
2.26 (s, 3 H, MeCO); 3.18 (s, 3 H,
MeOCH2); 3.42 (m, 1 H); 3.73 (m,
1 H); 3.86 (m, 1 H); 4.22 (m, 1 H,
(CH2CH2)2N); 4.36 (s, 2 H,
MeOCH2); 6.87 (br.s, 2 H, NH2);
12.56 (br.s, 1 H, NH)
8c
48
85
79
187—188
56.77 6.12
56.91 6.03
21.98
22.07
C15H19N5O3 3400, 3308, 3184, 1.21 (t, 3 H, CH3CH2 J = 7.8);
2180, 1676, 1640
1.80, 1.95, 3.58, 3.84 (all m, 2 H each,
C(CH2CH2)2N); 2.25 (s, 3 H, Me);
4.10 (q, 2 H, MeCH2, J = 8.0);
6.70 (br.s, 2 H, NH2); 12.10 (br.s,
1 H, NH)
12a
12b
> 300
61.62 3.59
23.81
23.88
C15H11N5O2 3408, 3316, 3136, 1.55 (s, 3 H, Me); 6.92 (d, 1 H,
(285—286 °C, 61.43 3.78
2932, 2196, 1708, H(7), J = 8.1); 7.02 (m, 2 H, H(4),
EtOH)13
1640, 1592
H(5)); 7.11 (br.s, 2 H, NH2);
7.25 (td, 1 H, H(6), J = 7.3,
J = 1.9); 10.51 (br.s, 1 H, N(1´)H);
12.21 (br.s, 1 H, N(2´)H)
>300
62.47 4.08
62.53 4.26
22.95
22.79
C16H13N5O2 3408, 3316, 3128, 1.56 (s, 3 H, C(3´)Me); 2.27 (s,
2200, 1712, 1644, 3 H, C(7)Me); 6.88 (m, 2 H, H(5),
1604, 1592
H(6)); 7.06 (d, 1 H, H(4), J = 7.3);
7.13 (br.s, 2 H, NH2); 10.58 (br.s,
1 H, N(1)H); 12.22 (br.s, 1 H,
N(2´)H)
(to be continued)

Fourꢀcomponent synthesis of pyranopyrazoles
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 11, November, 2009 2367
Table 1 (continued)
Comꢀ
pound
Yield
(%)
M.p.
/°C
Found
Calculated
Molecular
formula
IR spectrum,
ν/cm–1
1H NMR, δ (J/Hz)
(%)
(ν(NH), ν(С≡N),
ν(C=O), δ(NH2),
ν(C=C))
C
H
N
12c
12d
81
284—286
64.65 5.03
64.47 5.11
20.76
20.88
C18H17N5O2 3308, 3176, 2200, 0.93 (t, 3 H, CH3CH2CH2N,
1700, 1640, 1596
J = 7.3); 1.48 (s, 3 H, Me); 1.66 (m,
2 H, MeCH2CH2N); 3.69 (t, 2 H,
MeCH2CH2N, J = 7.4); 7.08—7.14
(m, 6 H, H(4)—H(7), NH2); 12.23
(br.s, 1 H, NH)
76
>300
64.53 5.07
64.47 5.11
20.69
20.88
C18H17N5O2 3384, 3324, 3172, 0.55 (t, 3 H, CH3CH2CH2, J = 7.4);
2192, 1712, 1648, 1.04 (m, 2 H, MeCH2CH2); 1.85 (m,
1596
2 H, MeCH2CH2); 2.27 (s, 3 H,
C(7´)Me); 6.88 (m, 2 H, H(5),
H(6)); 7.08 (m, 3 H, H(4) + NH2);
10.57 (br.s, 1 H, N(1)H);
12.20 (br.s, 1 H, N(2´)H)
compounds were determined on a Boetius heating stage and
were uncorrected. Elemental analysis was performed with a
Perkin—Elmer 2400 microanalyzer.
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Received February 3, 2009;
in revised form July 2, 2009