1,5-Diphenyl-3,3-dicyano-1,5-pentanedione: A synthon for novel heterocycles

Article abstract of DOI:10.1080/10426500214878

1,5-Diphenyl-3,3-dicyano-1,5-pentanedione has been used to incorporate N, O, S to obtain 1,4-dihydropyridine, 4H-pyran, and 4H-thiopyran, which in turn serve as precursors for the synthesis of novel spiro heterocycles. All the compounds were characterized by IR and NMR spectral data.

Full text of DOI:10.1080/10426500214878

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Phosphorus, Sulfur, and Silicon and the Related
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1,5-Diphenyl-3,3-dicyano-1,5-pentanedione: A Synthon
for Novel Heterocycles
V. Padmavathi a , A. Balaiah a , A. Padmaja a & D. Bhaskar Reddy a
a Sri Venkareswara University, Tirupati, India
Published online: 27 Oct 2010.
To cite this article: V. Padmavathi , A. Balaiah , A. Padmaja & D. Bhaskar Reddy (2002): 1,5-Diphenyl-3,3-dicyano-1,5-
pentanedione: A Synthon for Novel Heterocycles, Phosphorus, Sulfur, and Silicon and the Related Elements, 177:12, 2791-2798
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Phosphorus, Sulfur and Silicon, 2002, Vol. 177:2791–2798
C
Copyright 2002 Taylor & Francis
1042-6507/02 $12.00 + .00
DOI: 10.1080/10426500290146785
1,5-DIPHENYL-3,3-DICYANO-1,5-PENTANEDIONE:
A SYNTHON FOR NOVEL HETEROCYCLES
V. Padmavathi, A. Balaiah, A. Padmaja, and D. Bhaskar Reddy
Sri Venkareswara University, Tirupati, India
(Received March 22, 2002; accepted May 10, 2002)
1,5-Diphenyl-3,3-dicyano-1,5-pentanedione has been used to incor-
porate N, O, S to obtain 1,4-dihydropyridine, 4H-pyran, and 4H-
thiopyran, which in turn serve as precursors for the synthesis of novel
spiro heterocycles. All the compounds were characterized by IR and
NMR spectral data.
Keywords: 1,4-Dihydropyridine; 4H-pyran; 4H-thiopyran; spiro
heterocycles
INTRODUCTION
At the outset we choose to study the chemistry of simple molecules
for designing novel structures capable of performing a variety of func-
tions. One such system is 1,5-diaryl-3,3-disubstituted-1,5-pentanedione
which has been obtained by the reaction of phenacyl bromide with active
methylene compounds such as dimethylmalnoate, ethyl cyanoacetate
and malononitrile.1 The synthetic utility and reactivity of 1,5-diaryl-
3,3-dimethoxycarbonyl-3-cyano-3-ethoxycarbonyl-1,5-pentanediones
has been exploited for the incorporation of N, O, S as heteroatoms to
obtain 2,6-diaryl-4,4-dimethoxycarbonyl-4-cyano-4-ethoxycarbonyl-1,
4-dihydropyridine,2,6-diaryl-4,4-dimethoxycarbonyl-4-cyano-4-etho-
xycarbonyl-4H-pyran and 2,6-diaryl-4,4-dimethoxycarbonyl-4-cyano-4-
ethoxycarbonyl-4H-thiopyran. These results led us to plan and execute
the synthesis of some spiro heterocycles by exploting the gem diester/
cyanoester functionalities of the latter compounds.2–4 Following theses
observations and being undeterred by the results,5–10 we now report in
Two of the authors (V. P. and A. B.) are grateful to CSIR, New Delhi for financial
assistance.
Address correspondence to V. Padmavathi, Department of Chemistry, Sri
Venkareswara University, Tirupati, 517 502, India. E-mail: vkpuram2001@yahoo.com
2791

2792
V. Padmavathi et al.
the present communication on the reactivity of 1,5-diaryl-3,3-dicyano-
1,5-pentanedione.
RESULTS AND DISCUSSION
The key precursors 2,6-diphenyl-4,4-dicyanodihydropyridine (II), 2,6-
diphenyl-4,4-dicyano-4H-pyran (III), and 2,6-diphenyl-4,4-dicyano-4H-
thiopyran (IV) were prepared by treatment of 1,5-diaryl-3,3-dicyano-
1,5-pentanedione (I) with ammonium acetate in acetic acid,11 P2O5
in dry benzene,12 and P2S5 in xylene13 respectively. The absence of
carbonyl absorption around 1690 in their IR spectra indicated the
formation of II–IV. Further, the presence of a band around 3300 (NH)
indicates he formation of II. The 1H NMR spectra of II–IV showed
a singlet in the region 5.08–5.98 ppm which account for (C3-H and
C5-H) protons. The 13C NMR spectra exhibited resonance signals for
ring carbons of II–IV at 106.25–121.62 (C3 and C5), 142.13–149.44 (C2
and C6) and 42.41–44.53 (C4). The cyclocondensation of II–IV with
hydrazine hydrate and hydroxylamine hydrochloride in the presence
of NaOMe furnished, 7,9-diphenyl-2,3,8-triaza-spiro[4.5] deca-1,3,6,9-
tetraene-1,4-diamine (V)/7,9-diphenyl-8-oxa-2,3-diaza-spiro[4.5]deca-
1,3,6,9-tetraene-1,4-diamine (VI)/7,9-diphenyl-8-thia-2,3-diaza-spiro
[4.5]deca-1,3,6,9-tetraene-1,4-diamine (VII), 1-imino-7,9-diphenyl-2-
oxa-3,8-diaza-spiro[4.5]deca-3,6,9-trien-4-ylamine (VIII)/1-imino-7,
9-diphenyl-2,8-dioxa-3-aza-spiro[4.5]deca-3,6,9-trien-4-ylamine (IX)/1-
imino-7,9-diphenyl-2-oxa-8-thia-3-aza-spiro[4.5]deca-3,6,9-trien-4-yla-
mine (X) respectively. A similar reaction of II–IV with urea and
thiourea in presence of NaOMe, MeOH gave 1,5-diamino-8,10-diphenyl-
2,4,9-triaza-spiro[5.5]undeca-1,4,7,10-tetraen-3-one (XI)/1,5-diamino-
8,10-diphenyl-9-oxa-2,4-diaza-spiro[5.5]undeca-1,4,7,10-tetraen-3-one
(XII)/1,5-diamino-8,10-diphenyl-9-thia-2,4-diaza-spiro[5.5]undeca-1,4,
7,10-tetraen-3-one (XIII), and 1,5-diamino-8,10-diphenyl-2,4,9-tria-
za-spiro[5.5]undeca-1,4,7,10-tetraene-3-thione (XIV)/1,5-diamino-8,
10-diphenyl-9-oxa-2,4-diaza-spiro[5.5]undeca-1,4,7,10-tetraene-3-thio-
ne (XV)/1,5-diamino-8,10-diphenyl-9-thia-2,4-diaza-spiro[5.5]undeca-
1,4,7,10-tetraene-3-thione (XVI) respectively (Scheme 1 and Table I).
The IR spectra of V–XVI exhibited absorption bands in the region
1650–1690 (CONH and NHCONH) and 3200–3300 (NH2, NH). Apart
from this XVI showed a absorption at 1521 (C S). The methine protons
of V–XVI showed a singlet almost in the same region as in II–IV, apart
from this another singlet was observed for NH2 and NH in the region
6.41–9.94 ppm. The
values obtained for V–XVI further supports
C
their structures (Table II).

A Synthon for Novel Heterocycles
2793
SCHEME 1

2794
V. Padmavathi et al.
TABLE I Physical and Analytical Data of Compounds II–XVI
Found (calcd.) %
m.p.
( C)
Yield
(%)
Mol. formula
(mol. wt.)
Compd. no.
C
H
N
II
176–178
141–142
182–183
273–275
249–251
263–265
233–234
205–206
211–212
277–279
289–291
268–270
295–297
282–284
286–288
65
55
51
57
59
54
61
58
63
57
60
57
63
65
59
C19H13N3
(283.34)
80.70
4.55
15.05
(80.54) (4.62) (14.83)
III
IV
C
19H12N2O
(284.32)
80.34
(80.27) (4.25)
75.89 4.09
(75.97) (4.03)
72.52 5.50
4.33
10.01
(9.85)
9.48
(9.33)
22.32
C19H12N2S
(300.38)
C19H17N5
(315.38)
C19H16N4O
(316.37)
V
(72.36) (5.43) (22.21)
72.02 5.14 17.56
(72.14) (5.10) (17.71)
68.50 4.96 16.70
(68.65) (4.85) (16.85)
72.35 5.04 17.85
(72.14) (5.10) (17.71)
71.80 4.82 13.32
(71.91) (4.76) (13.24)
68.28 4.46 12.76
(68.45) (4.53) (12.60)
70.14 5.11 20.23
(69.96) (4.99) (20.39)
69.92 4.77 16.38
(69.76) (4.68) (16.27)
66.75 4.40 15.71
(66.65) (4.47) (15.54)
66.70 4.72 19.60
(66.83) (4.77) (19.48)
66.50 4.57 15.45
(66.65) (4.47) (15.54)
63.98 4.20 15.01
(63.80) (4.28) (14.88)
VI
VII
VIII
IX
C
19H16N4S
(332.43)
C19H16N4O
(316.37)
C
19H15N3O2
(317.35)
X
C
19H15N3OS
(333.41)
XI
C20H17N5O
(343.39)
XII
XIII
XIV
XV
XVI
C
20H16N4O2
(344.38)
C20H16N4OS
(360.44)
C
20H17N5S
(359.46)
C
20H16N4OS
(360.44)
C20H16N4S2
(376.51)
Conclusion
The versatality of carbonyl and dicyano functions have been made use
as tools for the synthesis of novel spiro heterocycles by a facile synthetic
strategy.
EXPERIMENTAL
Melting points were determined on Mel-Temp apparatus and were un-
corrected. The IR spectra were recorded on Perkin-Elmer 1600 series
FT-IR spectrometer using KBr pellets. The wave numbers were given

A Synthon for Novel Heterocycles
2795
TABLE II NMR Spectral Data of Compounds II–XVI
Compd. no.
1H NMR ( , ppm)
13C NMR ( , ppm)
II
5.08 (s, 2H, C3 and C5-H),
7.25–7.80 (m, 10H, ArH),
8.71 (s, 1H, NH)
42.41 (C4), 107.69 (C3 and C5),
113.98 (CN), 142.13 (C2 and C6)
III
IV
V
5.79 (s, 2H, C3 and C5-H),
7.26–7.78 (m, 10H, ArH)
5.98 (s, 2H, C3 and C5-H),
7.25–7.81 (m, 10H, ArH)
4.84 (s, 2H, C6 and C10-H),
7.23–7.89 (m, 10H, ArH),
9.25 (bs, 5H, NH2 and NH)
4.87 (s, 2H, C6 and C10-H),
7.24–7.80 (m, 10H, ArH),
9.17 (bs, 4H, NH2)
43.01 (C4), 106.25 (C3 and C5),
114.26 (CN), 149.15 (C2 and C6)
44.53 (C4), 121.62 (C3 and C5),
113.54 (CN), 142.44 (C2 and C6)
48.46 (C5), 112.67 (C6 and C10),
139.25 (C7 and C9), 174.12
(C1 and C4)
41.24 (C5), 109.41 (C6 and C10),
146.69 (C7 and C9), 173.85
(C1 and C4)
50.49 (C5), 126.23 (C6 and C10),
142.58 (C7 and C9), 176.94
(C1 and C4)
47.92 (C5), 111.29 (C6 and C10),
141.49 (C7 and C9), 172.21,
178.49 (C1 and C4)
50.74 (C5), 107.46 (C6 and C10),
149.42 (C7 and C9), 172.47,
178.79 (C1 and C4)
49.23 (C5), 125.26 (C6 and C10),
142.96 (C7 and C9), 174. 23,
180.12 (C1 and C4)
45.64 (C6), 112.91 (C7 and C11),
140.19 (C8 and C10), 159.82 (C3),
168.01 (C1 and C5)
50.68 (C6), 107.68 (C7 and C11),
148.98 (C8 and C10), 159.68 (C3),
168.29 (C1 and C5)
49.49 (C6), 128.34 (C7 and C11),
142.12 (C8 and C10), 159.59 (C3),
168.42 (C1 and C5)
48.89 (C6), 113.24 (C7 and C11),
140.09 (C8 and C10), 161.24
(C1 and C5), 172.48 (C3)
51.62 (C6), 107.56 (C7 and C11),
149.24 (C8 and C10), 161.43
(C1 and C5), 172.26 (C3)
52.46 (C6), 128.29 (C7 and C11),
142.86 (C8 and C10), 167.99
(C1 and C5), 172.08 (C3)
VI
VII
VIII
IX
5.74 (s, 2H, C6 and C10-H),
7.24–7.79 (m, 10H, ArH),
9.67 (bs, 4H, NH2)
4.82 (s, 2H, C6 and C10-H),
6.42–6.44 (bs, 4H, NH2, NH),
7.20–7.78 (m, 10H, ArH)
4.96 (s, 2H, C6 and C10-H),
6.49–6.52 (bs, 3H, NH2, NH),
7.22–7.79 (m, 10H, ArH)
5.88 (s, 2H, C6 and C10-H),
6.45–6.47 (bs, 3H, NH2, NH),
7.24–7.80 (m, 10H, ArH)
4.79 (s, 2H, C7 and C11-H),
6.41–6.42 (bs, 5H, NH2, NH),
7.23–7.78 (m, 10H, ArH)
4.90 (s, 2H, C7 and C11-H),
6.41 (bs, 4H, NH2),
7.24–7.80 (m, 10H, ArH)
5.87 (s, 2H, C7 and C11-H),
6.44 (bs, 4H, NH2),
7.20–7.78 (m, 10H, ArH)
4.74 (s, 2H, C7 and C11-H),
7.25–7.79 (m, 10H, ArH),
9.94 (bs, 5H, NH2 and NH)
4.92 (s, 2H, C7 and C11-H),
7.23–780 (m, 10H, ArH),
9.94 (bs, 4H, NH2)
X
XI
XII
XIII
XIV
XV
XVI
5.90 (s, 2H, C7 and C11-H),
7.24–7.79 (m, 10H, ArH),
9.93 (bs, 4H, NH2)

2796
V. Padmavathi et al.
in cm 1. NMR spectra were recorded on a Bruker spectrospin 300 MHz
spectrometer with TMS as an internal standard using CDCl3/DMSO-d6
as solvent. The chemical shifts were measured in ppm. The elemental
analyses were obtained from Micro analytical laboratory, University of
Pune, Pune, India. Purity of the compounds were checked by TLC using
silica gel ‘G’ (BDH) and hexane-ethyl acetate (3:1) as eluents.
General Procedure for the Preparation
of 2,6-Diphenyl-4,4-dicyano-1,4-dihydropyridine (II)
A mixture of I (10 mmol), ammonium acetate (1.5 g) and acetic acid
(20 ml) was refluxed for 3 h. The reaction mixture was cooled and
poured onto crushed ice. The product obtained was recrystallized from
methanol to get II.
General Preparation for the Preparation
of 2,6-Diphenyl-4,4-dicyano-4H-pyran (III)
The compound I (10 mmol) was dissolved in dry benzene (30 ml). To
this phosphorus pentoxide (2 g) was added and refluxed for 6–10 h us-
ing Dean-Stark apparatus. The reaction mixture was filtered, washed
with water and brine, and dried (an. Na2SO4). Evaporation of the sol-
vent under vacuo resulted a residue which on recrystallization from
methanol furnished III.
General Procedure for the Preparation
of 2,6-Diphenyl-4,4-dicyano-4H-thiopyran (IV)
To a solution I (10 mmol) in xylene (25 ml), phosphorus pentasulfide
(15 mmol) was added and refluxed for 12 h at 130–140 C. The reaction
mixture was cooled and filtered to remove excess phosphorus pentasul-
fide. The solvent was removed under reduced pressure. The residue was
recrystallized from methanol to afford IV.
General Procedure for the Preparation of 7,9-Diphenyl-
2,3,8-triaza-spiro[4.5]deca-1,3,6,9-tetraene-1,4-diamine
(V)/7,9-Diphenyl-8-oxa-2,3-diaza-spiro[4.5]deca-1,3,6,9-
tetraene-1,4-diamine (VI)/7,9-Diphenyl-8-thia-2,3-
diaza-spiro[4.5]deca-1,3,6,9-tetraene-1,4-diamine (VII)
The compound II/III/IV (10 mmol), 80% hydrazine hydrate (15 mmol)
in methanol (25 ml) was taken. To this 10% NaOMe (5 ml) was added
and refluxed for 5–6 h. The contents were cooled and poured onto

A Synthon for Novel Heterocycles
2797
crushed ice containing AcOH. The product obtained was recrystallized
from methanol to get V/VI/VII.
General Procedure for the Preparation
of 1-Imino-7,9-diphenyl-2-oxa-3,8-diaza-spiro[4.5]deca-
3,6,9-trien-4-ylamine (VIII)/1-Imino-7,9-diphenyl-
2,8-dioxa-3-aza-spiro[4.5]deca-3,6,9-trien-4-ylamine
(IX)/1-Imino-7,9-diphenyl-2-oxa-8-thia-3-aza-spiro
[4.5]deca-3,6,9-trien-4-Ylamine (X)
To an equimolar (10 mmol) mixture of II/III/IV and hydroxylamine
hydrochloride, 10% NaOMe (5 ml) was added and refluxed for 5 h. The
reaction mixture was cooled, poured onto crushed ice, and acidified with
AcOH. The crude product separated was filtered and recystallized from
methanol to afford VIII/IX /X.
General Procedure for the Preparation
of 1,5-Diamino-8,10-diphenyl-2,4,9-triaza-
spiro[5.5]undeca-1,4,7,10-tetraen-3-one
(XI)/1,5-Diamino-8,10-diphenyl-9-oxa-2,4-diaza-
spiro[5.5]undeca-1,4,7,10-tetraen-3-one
(XII)/1,5-Diamino-8,10-diphenyl-9-thia-2,4-diaza-spiro
[5.5]undeca-1,4,7,10-tetraen-3-one (XIII)
A mixture of II/III /IV (5 mmol), urea (5 mmol), methanol (20 ml), and
10% NaOMe (3 ml) was refluxed for 8–10 h. The solution was cooled
and poured onto crushed ice containing AcOH. The solid obtained was
separated and recystallized from methanol to furnish XI/XII/XIII.
General Procedure for the Preparation
of 1,5-Diamino-8,10-diphenyl-2,4,9-triaza-
spiro[5.5]undeca-1,4,7,10-tetraene-3-thione
(XIV)/1,5-Diamino-8,10-diphenyl-9-oxa-2,4-diaza-
spiro[5.5]undeca-1,4,7,10-tetraene-3-thione
(XV)/1,5-Diamino-8,10-diphenyl-9-thia-2,4-diaza-
spiro[5.5]undeca-1,4,7,10-tetraene-3-thione (XVI)
To an equimolar solution (10 mmol) of II/III/IV and thiourea, 10%
NaOMe (5 ml) was added and refluxed for 9–10 h. The reaction mix-
ture was cooled, poured onto crushed ice and acidified with AcOH. The
resultant solid was separated and recrystallized from methanol to get
XIV/XV/XVI.

2798
V. Padmavathi et al.
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