2,6-Diaryl-4,4-disubstituted-4H-thiopyran: Source for spiro heterocycles

Article abstract of DOI:10.1002/jhet.5570390408

The 1,5-diaryl-3,3-disubstituted-1,5-pentanedione on reaction with ammonium acetate, phosphorus pentoxide and phosphorus pentasulfide gave respective 1,4-dihydropyridine, 4H-pyran and 4H-thiopyran. Novel spiro heterocycles have been obtained by the cyclocondensation of 4H-thiopyran with hydrazine, hydroxylamine, urea and thiourea.

Full text of DOI:10.1002/jhet.5570390408

Jul-Aug 2002
2,6-Diaryl-4,4-disubstituted-4H-thiopyran:
Source for Spiro Heterocycles
649
Venkatapuram Padmavathi*, Akula Balaiah and Dandu Bhaskar Reddy
Department of Chemistry, Sri Venkateswara University, Tirupati -517 502, India
Received October 22, 2001
The 1,5-diaryl-3,3-disubstituted-1,5-pentanedione on reaction with ammonium acetate, phos-
phorus pentoxide and phosphorus pentasulfide gave respective 1,4-dihydropyridine, 4H-pyran
and 4H-thiopyran. Novel spiro heterocycles have been obtained by the cyclocondensation of 4H-
thiopyran with hydrazine, hydroxylamine, urea and thiourea.
J. Heterocyclic Chem., 39, 649 (2002).
As a result of our sustained efforts in the search for new
4-cyano-4-ethoxycarbonyl-1,4-dihydropyridine (4), 2,6-
diaryl-4,4-dimethoxycarbonyl-4H-thiopyran (5) or 2,6-
diaryl-4-cyano-4-ethoxycarbonyl-4H-thiopyran (6) and
2,6-diaryl-4,4-dimethoxycarbonyl-4H-pyran (7) or 2,6-
diaryl-4-cyano-4-ethoxycarbonyl-4H-pyran (8) respec-
tively (see Scheme 1 and Table 1) . Displacement of the
oxygen atom in 7 or 8 on treatment with excess phospho-
rus pentasulfide in boiling xylene also gave 5 or 6. The
absence of carbonyl absorption (ArCO) around 1690 in IR
spectra of 3-8 indicated their formation. Further 3 or 4
and versatile multi-functional reactive intermediates,
recently we have reported the preparation of 1,5-diaryl-
3,3-disubstituted-1,5-pentanediones 1 and 2 by the reac-
tion of phenacyl bromide with dimethyl malonate and eth-
ylcyano acetate [1]. The presence of dicarbonyl functional-
ity in 1 and 2 enabled us to incorporate N, O and S as het-
eroatoms in them [2]. This gave scope for us to design and
develop hitherto unknown spiro heterocycles by exploiting
the gem diester or cyano ester groups of 1,4-dihydropyri-
dine (3 and 4), 4H-thiopyran (5 and 6) and 4H-pyran (7
and 8). In fact, during the last decade we were actively
involved in the syntheses of several spiro-heterocycles [3].
In further development of this synthetic strategy, we have
now considered the reactivity of the 2,6-diaryl-4,4-disub-
stituted-4H-thiopyran(5 and 6) with hydrazine, hydroxy-
lamine, urea and thiourea.
1
showed a band around 3350-3450 for (NH). The H NMR
spectra of 3-8 showed a singlet in the region 5.22 – 5.86,
which accounts for C -H and C -H protons. However in
3
5
case of 3 and 4 a singlet was observed around 9.02 - 9.20
13
for NH which disappeares on deuteration. The C NMR
spectra of 3-8 exhibited resonance signals at 142.15 –
152.28 (C and C ), 91.78 – 120.54 (C and C ) and 41.24
2
6
3
5
The synthetic method involves the reaction of 1,5-
diaryl-3,3-dimethoxycarbonyl-1,5-pentanedione (1) or
1,5-diaryl-3-cyano-3-ethoxycarbonyl-1,5-pentanedione
(2) with ammonium acetate in acetic acid, phosphorus pen-
tasulfide in xylene and phosphorus pentoxide in dry ben-
zene under reflux conditions to obtain 2,6-diaryl-4,4-
dimethoxycarbonyl-1,4-dihydropyridine (3) or 2,6-diaryl-
– 45.67 (C ) which also support their structures (Table 3).
4
The cyclocondensation of 5 with hydrazine, hydroxy-
lamine, urea and thiourea in the presence of sodium
methoxide resulted in the formation of 7,9-diaryl-8-thia-
2,3-diaza-spiro[4,5]deca-6,9-diene-1,4-dione (9), 7,9-
diaryl-2-oxa-8-thia-3-aza-spiro[4,5]deca-6,9-diene-1,4-
dione (10), 8,10-diaryl-9-thia-2,4-diaza-spiro[5,5]undeca-

650
V. Padmavathi, A. Balaiah and D. B. Reddy
Vol. 39
Table 1
Physical Properties for Compounds 3-8
Table 2
Physical Properties for Compounds 9-16
Comp. M.P
(°C)
Yield Molecular formula
(%) (Molecular weight)
Calcd. (Found) %
Comp. M.P
(°C)
Yield Molecular formula
(%) (Molecular weight)
Calcd. (Found) %
C
H
N
C
H
N
3a
3b
3c
4a
4b
4c
5a
5b
5c
6a
6b
6c
7a
7b
7c
8a
8b
8C
168-169
182-183
148-149
152-153
170-171
132-133
181-182
192-194
168-169
158-159
172-173
146-147
143-144
151-152
175-176
132-133
149-150
135-136
68
71
64
66
69
62
C
H
NO
72.19
5.48
4.01
21 19
4
9a
9b
9c
245-247 68
C
C
H
N O S
68.24
4.22
8.38
19 14
2 2
349.38
NO
(72.33) (5.54) (3.97)
67.47 5.66 3.42
(67.25) (5.78) (3.57)
60.30 4.10 3.35
(60.43) (4.16) (3.19)
76.34 5.49 8.48
(76.50) (5.53) (8.29)
70.75 5.68 7.17
(70.62) (5.72) (7.29)
63.17 4.04 7.02
(63.08) (4.12) (7.13)
69.83
(69.70) (5.02)
64.77 5.20
(64.66) (5.07)
57.94 3.70
(57.84) (3.79)
72.59 4.93
(72.42) (4.97) (4.16)
67.79 5.19 3.43
(67.92) (5.06) (3.55)
60.58 3.63 3.36
(60.73) (3.72) (3.47)
71.99
(71.81) (5.12)
67.31 5.40
(67.50) (5.47)
60.16 3.85
(60.28) (3.90)
76.12 5.17
334.39
H N O S
(68.10) (4.12) (8.23)
63.94 4.60 7.10
(64.15) (4.51) (7.22)
56.59 3.00 6.94
(56.70) (2.93) (6.78)
68.04 3.91 4.18
(68.26) (3.84) (4.31)
63.79 4.33 3.54
(63.56) (4.40) (3.63)
56.45 2.74 3.46
(56.53) (2.70) (3.38)
66.28 3.89 7.73
(66.38) (3.97) (7.63)
62.55 4.29 6.63
(62.75) (4.36) (6.70)
55.70 2.80 6.49
(55.54) (2.87) (6.35)
63.47 3.73 7.40
(63.55) (3.65) (7.50)
60.26 4.14 6.39
(60.14) (4.24) (6.27)
53.70 2.70 6.26
(53.88) (2.65) (6.37)
68.45 4.53 12.60
(68.58) (4.44) (12.75)
64.10 4.87 10.68
(64.15) (4.80) (10.80)
56.73 3.26 10.44
(56.59) (3.36) (10.35)
68.24 4.22 8.38
(68.09) (4.17) (8.51)
63.94 4.60 7.10
(63.71) (4.56) (7.23)
56.59 3.00 6.95
(56.74) (3.07) (6.83)
66.46 4.18 11.63
(66.65) (4.27) (11.72)
62.69 4.54 9.97
(62.77) (4.59) (9.85)
55.82 3.05 9.77
(55.66) (2.98) (9.81)
63.64 4.01 11.13
(63.54) (4.08) (11.28)
60.39 4.38 9.60
(60.57) (4.48) (9.49)
53.81 2.94 9.41
(53.70) (2.88) (9.58)
C
H
23 23
6
238-240 64
229-231 59
21 18
2 4
409.43
H Cl NO
394.44
C H Cl N O S
19 12
C
21 17
2
4
2 2 2
418.27
N O
403.28
NO S
C
H
21 18
2
2
10a 199-200 69
10b 211-212 61
C
C
H
19 13
3
330.38
N O
335.37
NO S
C
H
23 22
2
4
H
21 17
5
390.43
H Cl N O
395.43
C
21 16
2
2
2
10c
11a
185-186 70
280-282 55
C H C NO S
19 11 l2 3
399.27
O S
404.26
H N O S
362.42
H N O S
40
57*
35
51*
38
59*
42
62*
39
50*
45
52*
65
C
C
H
4.95
-
21 18
4
C
20 14 2 3
366.43
O S
H
-
-
-
23 22
6
11b 286-288 58
11c 274-276 51
C
22 18
2 5
426.48
H Cl O S
422.45
C H Cl N O S
20 12
431.29
C H N O S
20 14
378.46
C H N O S
22 18
438.52
C H Cl N O S
20 12
447.36
C H N OS
19 15
333.40
C H N O S
21 19
393.46
C H Cl N OS
19 13
402.29
C H N O S
19 14
C
21 16
2
4
2 2 3
435.32
NO S
C
H
4.03
21 17
2
12a 282-284 60
12b 277-279 59
2
2
2
2
347.43
NO S
C
H
23 21
4
2 4
407.48
H Cl NO S
C
21 15
2
2
12c
13a
268-270 57
210-211 63
2 2 2 2
416.32
C
C
H
O
5.18
-
21 18
5
3
350.36
72
69
78
75
71
H
O
-
-
23 22
7
13b 245-247 54
13c 233-234 62
3 3
410.41
Cl O
C
H
21 16
2
5
2 3
419.25
NO
C
H
4.23
21 17
3
14a 182-183 65
14b 169-170 60
14C 195-196 58
15a 266-268 65
15b 272-274 69
2 2
331.36
NO
(76.37) (5.10) (4.33)
70.58 5.41 3.58
(70.77) (5.36) (3.69)
63.02 3.78 3.50
(62.90) (3.85) (3.32)
334.39
C H N O S
21 18
394.44
C H Cl N O S
19 12
C
H
23 21
5
2 4
391.41
H Cl NO
400.25
C
21 15
2
3
2 2 2
403.28
H N O S
C
C
20 15
3 2
* Yields obtained in method 2.
361.41
N O S
H
22 19
3 4
421.47
C H Cl N O S
20 13
430.31
C H N OS
20 15
15c
291-293 66
2 3 2
7,10-diene-1,3,5-trione (11) and 8,10-diaryl-3-thioxo-9-
thia-2,4-diaza-spiro[5,5]undeca-7,10-diene-1,5-dione (12)
respectively (see Scheme 2). In a similar way the reaction
of 6 in the presence of sodium ethoxide furnished 4-
amino-7,9-diaryl-8-thia-2,3-diazaspiro[4,5]deca-3,6,9-
trien-1-one (13), 4-amino-7,9-diaryl-2-oxa-8-thia-3-aza-
spiro[4,5]deca-3,6,9-trien-1-one (14), 5-amino-3-hydroxy-
8,10-diaryl-9-thia-2,4-diazaspiro[5,5]undeca-2,4,7,10-
tetraen-1-one (15) and 5-amino-3-mercapto-8,10-diaryl-9-
thia-2,4-diaza-spiro[5,5]undeca-2,4,7,10-teraen-1-one
(16) (see Scheme 3 and Table 2). The IR spectra of 9-16
exhibited absorption bands in the region 1495-1510 (C=S)
[4], 1655-1725 (CONH), 1745-1770 (CO-O), 3300-3440
16a 257-259 72
16b 294-296 68
3
2
377.48
H N O S
C
22 19
3 3 2
437.53
C H Cl N OS
20 13
16c
281-283 70
2
3
2
446.37
showed singlets at 1.41-1.42 (SH), 5.20-5.67 (C -H and
6
C -H, C -H and C -H) and 8.88-10.22 (NH , NH and
10
7
11
2
13
OH). The δ values obtained in their C NMR spectra
also support the structures (Table 4).
C
In conclusion, interesting spiro heterocycles were con-
veniently prepared by a straightforward successfully estab-
lished method from simple substrates such as phenacyl
bromide and active methylene compounds.
(OH) and 3100-3310 (CONH, and NH ). The absorption
2
for the SH group generally appears as a weak band around
2550-2600 [5], however this is not observed for our com-
1
pounds. The H NMR spectra of all these compounds

Jul-Aug 2002
2,6-Diaryl-4,4-disubstituted-4H-thiopyran: Source for Spiro Heterocycles
651
Table 3
Spectroscopic Data of Compounds 3-8
1
13
Compd.
H NMR
δ (CDCl ), ppm
C NMR
δ (CDCl ), ppm
3
3
3a
3b
3c
4a
4b
3.82 (s, 6H, CO CH ), 5.24 (s, 2H, C and C -H), 7.20-
45.21 (C ), 52.35 (CO CH ), 119.11 (C and C ),
4 2 3 3 5
2
3
3
5
7.74 (m, 10H, ArH), 9.03 (s, 1H, NH Exch. with D O)
142.15 (C and C ), 173.25 (COOCH )
2
2 6 3
3.62 (s, 6H, Ar-OCH ), 3.83 (s, 6H, CO CH ), 5.29 (s, 2H, C and
______
45.62 (C ), 52.41 (CO CH ), 119.27 (C and C ), 142.35
3
2
3
3
C -H), 7.19-7.75 (m, 8H, ArH), 9.22 (s, 1H, NH Exch. with D O)
5
2
3.83 (s, 6H, CO CH ), 5.22 (s, 2H, C and C -H), 7.22-
2
3
3
5
4
2
3
3
5
7.75 (m, 8H, ArH), 9.13 (s, 1H, NH Exch. with D O)
(C and C ), 173.28 (COOCH )
2
2 6 3
1.42 (t, 3H, -OCH CH ), 4.36 (q, 2H, -OCH CH ), 5.32 (s, 2H, C
14.21 (OCH CH , 45.23 (C ), 63.55 (-OCH CH ), 113.25 (CN),
2 3 4 2 3
2
3
2
3
3
and C -H), 7.24-7.75 (m, 10H, ArH), 9.20 (s, 1H, NH Exch. with D O) 120.24 (C and C ), 142.21 (C and C ), 169.48 (COOCH CH )
5
2
3
5
2
6
2
3
1.44 (t, 3H, -OCH CH ), 3.57 (s, 6H, Ar-OCH ), 4.35 (q, 2H,
14.19 (OCH CH ), 45.27 (C ), 51.62 (Ar-OCH ), 63.58
2
3
3
2 3 4 3
-OCH CH ), 5.38 (s, 2H, C and C -H), 7.23-7.75 (m, 8H, ArH,
(-OCH CH ), 113.54 (CN), 120.54 (C and C ), 142.28 (C
2 3 3 5 2
2
3
3
5
9.06 (s, 1H, NH exch. with D O)
and C ), 169.00 (COOCH CH )
2
6
2
3
4c
1.41 (t, 3H, -OCH CH ), 4.36 (q, 2H, -OCH CH ), 5.33 (s, 2H,
______
2
3
2
3
C and C -H), 7.24-7.75 (m, 8H, ArH), 9.11 (s, 1H, NH exch.
3
5
with D O)
2
5a
5b
5c
6a
6b
6c
7a
7b
7c
8a
8b
8c
3.78 (s, 6H, CO CH ), 5.84 (s, 2H, C and C -H), 7.19-7.75
45.49 (C ), 52.51 (CO CH ), 110.23 (C and C ), 145.17
4 2 3 3 5
2
3
3
5
(m, 10H, ArH)
3.61 (s, 6H, Ar-OCH ), 3.82 (s, 6H, CO CH ), 5.86 (s, 2H, C
(C and C ), 171.29 (COOCH )
2 6 3
45.57 (C ), 52.56 (CO CH ), 51.72 (Ar-OCH ), 110.77
3
2
3
3
4
2
3
3
and C -H), 7.22-7.75 (m, 8H, ArH)
(C and C ),145.61 (C and C ), 171.98 (COOCH )
5
3
5
2
6
3
3.79 (s, 6H, CO CH ), 5.82 (s, 2H, C and C -H), 7.20-7.75
______
2
3
3
5
(m, 8H, ArH)
1.43 (t, 3H, -OCH CH ), 4.37 (q, 2H, -OCH CH ), 5.77 (s,
14.68 (OCH CH ), 45.67 (C ), 63.65 (-OCH CH ), 110.82 (C
3
2
3
2
3
2
3
4
2
3
2H, C and C -H), 7.21-7.75 (m, 10H, ArH)
and C ), 113.61 (CN), 151.53 (C and C ), 168.89 (COOCH CH )
3
5
5
2
6
2
3
1.43 (t, 3H, -OCH CH ), 3.62 (s, 6H, Ar-OCH ), 4.38 (q, 2H,
______
2
3
3
-OCH CH ), 5.75 (s, 2H, C and C -H), 7.20-7.75 (m, 8H, ArH)
2
3
3
5
1.41 (t, 3H, -OCH CH ), 4.36 (q, 2H, -OCH CH ), 5.75
14.58 (OCH CH ), 45.66 (C ), 63.67 (-OCH CH ), 110.81 (C
2 3 4 2 3 3
2
3
2
3
(s, 2H, C and C -H), 7.21-7.76 (m, 8H, ArH)
and C ), 113.58 (CN), 152.28 (C and C ), 168.57 (COOCH CH )
3
5
5 2 6 2 3
3.80 (s, 6H, CO CH ), 5.76 (s, 2H, C and C -H), 7.25-7.75
41.52 (C ), 53.21 (CO CH ), 93.72 (C and C ), 149.98 (C
4 2 3 3 5
2
3
3
5
2
(m, 10H, ArH)
3.62 (s, 6H, Ar-OCH ), 3.83 (s, 6H, CO CH ), 5.72 (s, 2H,
and C ), 170.18 (COOCH )
6
3
______
3
2
3
C and C -H), 7.28-7.75 (m, 8H, ArH)
3
5
3.81 (s, 6H, CO CH ), 5.75 (s, 2H, C and C -H), 7.29-7.74
41.95 (C ), 53.26 (CO CH ), 91.78 (C and C ), 149.00 (C
4 2 3 3 5
2
3
3
5
2
(m, 8H, ArH)
1.40 (t, 3H, -OCH CH ), 4.35 (q, 2H, -OCH CH ), 5.62 (s,
and C ), 169.97 (COOCH )
6 3
14.18 (OCH CH ), 41.08 (C ), 63.54 (-OCH CH ), 94.05 (C
3
2
3
2
3
2
3
4
2
3
2H, C and C -H), 7.24-7.77 (m, 10H, ArH)
and C ), 112.80 (CN), 151.48 (C and C ), 167.82 (COOCH CH )
3
5
5
2
6
2
3
1.43 (t, 3H, -OCH CH ), 3.59 (s, 6H, Ar-OCH ), 4.33 (q, 2H,
______
2
3
3
-OCH CH ), 5.65 (s, 2H, C and C -H), 7.22-7.74 (m, 8H, ArH)
2
3
3
5
1.39 (t, 3H, -OCH CH ), 4.38 (q, 2H, -OCH CH ), 5.64 (s, 2H,
14.15 (-OCH CH ), 41.24 (C ), 63.56 (-OCH CH ), 94.90 (C and
2 3 4 2 3 3
2
3
2
3
C and C -H), 7.21-7.72 (m, 8H, ArH)
C ), 112.77 (CN), 151.42 (C and C ), 168.11 (COOCH CH )
3
5
5 2 6 2 3

652
V. Padmavathi, A. Balaiah and D. B. Reddy
Vol. 39
Table 4
Spectroscopic Data of Compounds 9-16
1
13
Compd
H NMR
δ (DMSO-d , ppm
C NMR
δ (DMSO-d ), ppm
6)
6
9a
5.25 (s, 2H, C and C -H), 7.25-7.76 (m, 10H, ArH), 9.09
45.18 (C ), 117.22 (C and C ), 145.20 (C and C ),
5 6 10 7 9
6
10
(s, 2H, NH Exch. with D O)
169.48 (C and C )
2
1 4
9b
3.62 (s, 6H, Ar-OCH ), 5.23 (s, 2H, C and C -H), 7.22-7.77
45.01 (C ), 51.68 (Ar-OCH ), 117.29 (C and C ),
5 3 6 10
3
6
10
(m, 8H, ArH), 9.17 (s, 2H, NH Exch. with D O)
145.25 (C and C ), 169.29 (C and C )
2
7 9 1 4
9c
5.20 (s, 2H, C and C -H), 7.21-7.75 (m, 8H, ArH), 9.25
______
46.22 (C ), 117.39 (C and C ), 146.21 (C and C ),
6
10
(s, 2H, NH Exch. with D O)
2
10a
10b
10c
11a
11b
11c
12a
12b
12c
13a
13b
13c
14a
14b
14c
15a
15b
5.27 (s, 2H, C and C -H), 7.22-7.76 (m, 10H, ArH), 10.15
6 10
5
6
10
7
9
(s, 1H, NH Exch. with D O)
169.23, 171.45 (C and C )
46.84 (C ), 51.72 (Ar-OCH ), 117.98 (C and C ), 146.54
5 3 6 10
2
1 4
3.60 (s, 6H, Ar-OCH ), 5.31 (s, 2H, C and C -H), 7.28-7.87
3
6
10
(m, 8H, ArH), 10.18 (s, 1H, NH Exch. with D O)
(C and C ), 169.02, 171.51 (C and C )
2
7
9
1
4
5.52 (s, 2H, C and C -H), 7.21-7.76 (m, 8H, ArH), 10.22
______
6
10
(s, 1H, NH Exch. with D O)
2
5.61 (s, 2H, C and C -H), 7.38-7.76 (m, 10H, ArH), 9.01
45.28 (C ), 117.49 (C and C ), 146.99 (C and C ),
6 7 11 8 10
7
11
(s, 2H, NH Exch. with D O)
159.82 (C ) 171.97 (C and C )
2
3 1 5
3.60 (s, 6H, Ar-OCH ), 5.63 (s, 2H, C and C -H), 7.22-7.81
______
______
3
7
11
(m, 8H, ArH), 8.88 (s, 2H, NH Exch. with D O)
2
5.61 (s, 2H, C and C -H), 7.21-7.75 (m, 8H, ArH), 8.89
7
11
(s, 2H, NH Exch. with D O)
2
5.53 (s, 2H, C and C -H), 7.22-7.76 (m, 10H, ArH), 9.12
45.50 (C ), 118.04 (C and C ), 147.02 (C and C ),
6 7 11 8 10
7
11
(s, 2H, NH Exch. with D O)
159.87 (C ) 171.64 (C and C )
2
3 1 5
3.62 (s, 6H, Ar-OCH ), 5.55 (s, 2H, C and C -H), 7.21-
______
45.42 (C ), 116.93 (C and C ), 147.52 (C and C ),
3
7
11
7.77 (m, 8H, ArH), 9.15 (s, 2H, NH Exch. with D O)
2
5.67 (s, 2H, C and C -H), 7.20-7.76 (m, 8H, ArH), 9.21 (s,
7
11
6
7
11
8
10
2H, NH Exch. with D O)
159.81 (C ) 171.59 (C and C )
2
3 1 5
5.49 (s, 2H, C and C -H), 7.20-7.75 (m, 10H, ArH), 9.32-
43.98 (C ), 119.14 (C and C ), 142.92 (C and C ),
5 6 10 7 9
6
10
9.36 (bs, 3H, NH , NH Exch.with D O)
165.02 (C ) 170.21 (C )
2
2
4 1
3.61 (s, 6H, Ar-OCH ), 5.44 (s, 2H, C and C -H), 7.21-7.75
______
44.26 (C ), 118.91 (C and C ), 143.76 (C and C ),
3
6
10
(m, 8H, ArH), 9.41-9.45 (bs, 3H, NH , NH Exch. with D O)
2
2
5.43 (s, 2H, C and C -H), 7.22-7.76 (m, 8H, ArH), 9.40-
6
10
5
6
10
7
9
9.43 (bs, 3H, NH , NH Exch. with D O)
164.12 (C ) 170.42 (C )
2
2
4 1
5.48 (s, 2H, C and C -H), 7.24-7.76 (m, 10H, ArH), 9.81
45.55 (C ), 119.12 (C and C ), 143.28 (C and C ),
5 6 10 7 9
6
10
(s, 2H, NH Exch. with D O)
165.49 (C ) 173.21 (C )
2
2
4 1
3.62 (s, 6H, Ar-OCH ), 5.47 (s, 2H, C and C -H), 7.25-
______
45.51 (C ), 119.92 (C and C ), 143.91 (C and C ),
3
6
10
7.75 (m, 8H, ArH), 9.83 (s, 2H, NH Exch. with D O)
2
2
5.45 (s, 2H, C and C -H), 7.23-7.77 (m, 8H, ArH), 9.84
6
10
6
6
10
7
9
(s, 2H, NH Exch. with D O)
164.91 (C ) 172.82 (C )
2
2
4 1
5.44 (s, 2H, C and C -H), 7.21-7.76 (m, 10H, ArH), 9.17
43.23 (C ), 117.62 (C and C ), 143.01 (C and C ),
6 7 11 8 10
7
11
(s, 1H, OH Exch. with D O), 9.89 (s, 2H, NH Exch. with D O)
162.34 (C ) 178.45 (C ), 186.77 (C )
2
2
2
3 1 5
3.58 (s, 6H, Ar-OCH ), 5.46 (s, 2H, C and C -H), 7.21-7.75
43.27 (C ), 51.71 (Ar-OCH ) 117.31 (C and C ), 143.24
6 3 7 11
3
7
11
(m, 8H, ArH), 9.16 (s, 1H, OH Exch. with D O), 9.80 (s, 2H,
(C and C ), 162.21 (C ) 178.92 (C ), 186.22 (C )
2
8
10
3
1
5
NH Exch. with D O)
2
2
15c
16a
16b
5.48 (s, 2H, C and C -H), 7.20-7.76 (m, 8H, ArH), 9.19 (s,
______
7
11
1H, OH Exch. with D O), 9.81 (s, 2H, NH Exch. with D O)
2
2
2
1.43 (s, 1H, SH Exch.. with D O), 5.47 (s, 2H, C and C -H),
41.49 (C ), 117.63 (C and C ), 144.79 (C and C ),
6 7 11 8 10
162.91 (C ) 176.76 (C ), 179.96 (C )
41.12 (C ), 51.69 (Ar-OCH ) 116.82 (C and C ), 145.31
6 3 7 11
2
7
11
7.21-7.77 (m, 10H, ArH), 9.62 (s, 2H, NH Exch. with D O)
2
2
3 1 5
1.45 (s, 1H, SH Exch. Exch. with D O), 3.60 (s, 6H, Ar-OCH ),
2
3
5.49 (s, 2H, C and C -H), 7.22-7.75 (m, 8H, ArH), 9.60 (s, 2H,
(C and C ), 163.54 (C ) 176.93 (C ), 180.54 (C )
7
11
8
10
3
1
5
NH Exch. with D O)
2
2
16c
1.41 (s, 1H, SH Exch. with D O), 5.48 (s, 2H, C and C -H),
______
2
7
11
7.20-7.75 (m, 8H, ArH), 9.64 (s, 2H, NH Exch. with D O)
2
2
EXPERIMENTAL
pounds were checked by TLC using silica gel `G' (BDH) and
hexane-ethyl acetate as eluents.
Melting points were determined on Mel-Temp apparatus and
were uncorrected. The IR spectra were recorded on Perkin-Elmer
1600 FT-IR spectrometer using KBr disc. The wave numbers
were in cm . NMR spectra were recorded on a Bruker spectro-
spin 300 MHz spectrometer with TMS as an internal standard.
The chemical shifts were measured in ppm. Purity of the com-
2,6-Diaryl-4,4-dimethoxycarbonyl-1,4-dihydropyridine (3) or
2,6-diaryl-4-cyano-4-ethoxy- carbonyl-1,4-dihydropyridine (4).
-1
A mixture of 10 mmoles of 1 or 2 and 1.5 g of ammonium
acetate in 20 ml of acetic acid was refluxed for 2 hours. The reac-
tion mixture was cooled and poured onto crushed ice. The products

Jul-Aug 2002
2,6-Diaryl-4,4-disubstituted-4H-thiopyran: Source for Spiro Heterocycles
653
obtained were recrystallized from methanol to give 3 or 4 (Table
1).
2,4-diazaspiro[5,5]undeca-2,4,7,10-tetraen-1-one (15) and 5-
amino-3-mercapto-8,10-diaryl-9-thia-2,4-diazaspiro[5,5]undeca-
2,4,7,10-tetraen-1-one (16).
2,6-Diaryl-4,4-dimethoxycarbonyl-4H-pyran (7) or 2,6-Diaryl-4-
cyano-4-ethoxycarbonyl-4H-pyran (8).
To a solution of 10 mmoles of 6 in 20 ml of ethanol, 15
mmoles of hydrazine hydrate or 10 mmoles of either hydroxy-
lamine hydrochloride, urea or thiourea as appropriate (Scheme
3), 5 ml of 10% sodium ethoxide were added and refluxed for 6-
8 hours, The cooled reaction mixture was poured onto crushed
ice containing acetic acid. The solid separated was recrystallized
from methanol to give 13-16 (Table 2).
Compounds 1 or 2 (10 mmoles) were dissolved in 30 ml of dry
benzene. To this 2 g of phosphorus pentoxide was added and
refluxed for 8-10 hours using a Dean-Stark apparatus. The reac-
tion mixture was filtered, washed with water, brine and dried
(anhydrous Na SO ). The solvent was evaporated in vacuo, and
2
4
the resultant products were recrystallized from ethanol to fur-
nished 7 or 8 (Table 1).
Acknowledgements.
2,6-Diaryl-4,4-dimethoxycarbonyl-4H-thiopyran (5) or 2,6-
diaryl-4-cyano-4-ethoxycarbonyl-4H-thiopyran (6).
One of the authors (AB) wishes to thank CSIR, New Delhi,
India for the award of Senior Research Fellowship, while another
author (DBR) is grateful to UGC for the award of Emeritus
Fellowship to him.
Method 1.
To a solution of 10 mmoles of 1 or 2 in 25 ml of xylene, 15
mmoles of phosphorus pentasulfide was added and refluxed for
10 hours at 130-140 °C. The cooled contents were filtered to
remove excess phosphorus pentasulfide. The solvent was
removed under reduced pressure. The residue was recrystallized
from ethanol to afford 5 or 6 (Table 1).
REFERENCES AND NOTES
*
Author to whom correspondence should be sent: e-Mail:
bdandu@yahoo.com; Fax: 091-8574-50274.
[1a] R. M. Ray and J. N.V. Ray, J. Chem. Soc., 127, 2721
(1925); [b] D. Girdina, R. Ballini, G. M. Cingaolani and B. K. Pietroni,
Tet. Lett., 249 (1979); [c] Padmavathi, A. Balaiah and D. Bhaskar
Reddy, Indian J. Chem., (Communicated).
[2a] V. Baliah and T. Rangarajan, J. Org. Chem., 26, 970
(1961); [b] M. Schwarz, P. Trska and J. Kuthan, Collect. Czech. Chem.
Commun., 54, 1854 (1989); [c] P. Sebek, S. Nespurek, R. Hrabal, M.
Adamec and J. Kuthan, J. Chem. Soc. Perkin Trans. 2, 1301 (1992).
[3a] D. Bhaskar Reddy, V. Padmavathi and P. V. Ramana
Reddy, Indian J.Chem., 31B, 774 (1992); [b] D. Bhaskar Reddy, V.
Padmavathi, B. Seenaiah and A. Padmaja, Heteroatom Chem., 4, 55
(1993); [c] D. Bhaskar Reddy, M. V. Ramana Reddy and V.
Padmavathi, Indian J. Chem., 37B, 167 (1998); [d] D. Bhaskar Reddy,
M. V. Ramana Reddy and V. Padmavathi, Heteroatom Chem., 10, 17
(1999); [f] D. Bhaskar Reddy, N. Chandrasekhar Babu and V.
Padmavathi, Heteroatom Chem., 12, 113 (2001); [g] D. Bhaskar
Reddy, N. Chandrasekhar Babu and V. Padmavathi, J. Heterocyclic
Chem., 38, 769 (2001).
Method 2: Conversion of 7 or 8 to 5 or 6.
A solution of 5 mmoles of 7 or 8 in 20 m1 of xylene and 10
mmoles of phosphorus pentasulfide were refluxed for 3 hours
and worked up as described above to give 5 or 6 (Table 1).
7,9-Diaryl-8-thia-2,3-diazaspiro[4,5]deca-6,9-diene-1,4-dione
(9), 7,9-diaryl-2-oxa-8-thia-3-azaspiro[4,5]deca-6,9-diene-1,4-
dione (10), 8,10-diaryl-9-thia-2,4-diazaspiro[5,5]undeca-7,10-
diene-1,3,5-trione (11), 8,10-diaryl-3-thioxo-9-thia-2,4-diaza-
spiro[5,5]undeca-7,10-diene-1,5-dione (12).
A mixture of 10 mmoles of 5, 15 mmoles of 80% hydrazine
hydrate or 10 mmoles of either hydroxylamine hydrochloride,
urea or thiourea as appropriate (Scheme 2) in 20 ml of methanol
and 5 ml of 10% sodium methoxide was refluxed for 5-6 hours.
The solution was cooled and poured onto crushed ice containing
hydrochloric acid. The solid obtained was recrystallized from
methanol to give 9-12 (Table 2).
[4] Y. Kook Hoh, K. Bang and H. Kim, J. Heterocyclic Chem.,
38, 89 (2001).
4-Amino-7,9-diaryl-8-thia-2,3-diazaspiro[4,5]deca-3,6,9-trien-1-
one (13), 4-amino-7,9-diaryl-2-oxa-8-thia-3-azaspiro[4,5]deca-
3,6,9-trien-1-one (14), 5-amino-3-hydroxy-8,10-diaryl-9-thia-
[5] R. M. Silverstein, G. C. Bassler and T. C. Morrill,
"Spectometric Identification of Organic compounds" Fifth Edition,
John Wiley & Sons, New York, New York.