Synthesis and Fungicidal Activity of Novel 4,4′-Bis(2″ -aryl-5″-methyl/unsubstituted-4″-oxo-thiazolidin-3″-yl) Bibenzyl

Article abstract of DOI:10.1021/jf0342324

Reduction followed by nitration of benzil I yielded 4,4′- dinitrobibenzyl (III) which by reduction furnished quantitatively and analytically pure 4,4′-diaminobibenzyl (IV) which on condensation with different carbonyl compounds gave 4,4′-bis (benzylideneamino) bibenzyls (Va-f). Compounds (Va-f) on cycloaddition with mercaptoacetic acid/2-mercaptopropionic acid yielded the corresponding 4-oxothiazolidin-3-yl bibenzyls (Vla-I). The compounds VIg-I have two chiral centers in each thiazolidinone moiety so two diastereomers are possible, but on crystallization and repeated chromatography, one diastereomer was obtained. The absolute configuration of the diastereomer was tentatively assigned on the basis of ¹H NMR spectra. ¹H NMR spectra of the product showed a distinct doublet at δ 1.22 for C₅-CH₃ of thiazolidinone ring (22, 23) and a distinct quartet at δ4.20 for the C₅-H proton. Similarly, the C₂ proton showed an independent singlet at δ 5.95, so the diastereomers obtained were assigned trans configuration. Compounds Va-f and Vla-I were evaluated in vitro for their fungitoxicities against Fusarium oxysporium and Penicillium citrinum. All the compounds were found to be antifungal active. Some of the compounds displayed activities comparable with that of the commercial fungicide Dithane M-45. Structure-activity relationships for the screened compounds are discussed.

Full text of DOI:10.1021/jf0342324

7062 J. Agric. Food Chem. 2003, 51, 7062−7065
Synthesis and Fungicidal Activity of Novel
4,4′-Bis(2′′-aryl-5′′-methyl/unsubstituted-4′′-oxo-thiazolidin-3′′-yl)
Bibenzyl
IBADUR R. SIDDIQUI, PRAVIN K. SINGH,* JAYA SINGH, AND JAGDAMBA SINGH
Laboratory of Synthetic Organic Chemistry, Department of Chemistry, University of Allahabad,
Allahabad 211002, India
Reduction followed by nitration of benzil I yielded 4,4′-dinitrobibenzyl (III) which by reduction furnished
quantitatively and analytically pure 4,4′-diaminobibenzyl (IV) which on condensation with different
carbonyl compounds gave 4,4′-bis (benzylideneamino) bibenzyls (Va-f). Compounds (Va-f) on
cycloaddition with mercaptoacetic acid/2-mercaptopropionic acid yielded the corresponding 4-oxo-
thiazolidin-3-yl bibenzyls (VIa-l). The compounds VIg-l have two chiral centers in each thiazolidinone
moiety so two diastereomers are possible, but on crystallization and repeated chromatography, one
diastereomer was obtained. The absolute configuration of the diastereomer was tentatively assigned
on the basis of 1H NMR spectra. 1H NMR spectra of the product showed a distinct doublet at δ 1.22
for C5-CH3 of thiazolidinone ring (22, 23) and a distinct quartet at δ 4.20 for the C5-H proton. Similarly,
the C2 proton showed an independent singlet at δ 5.95, so the diastereomers obtained were assigned
trans configuration. Compounds Va-f and VIa-l were evaluated in vitro for their fungitoxicities against
Fusarium oxysporium and Penicillium citrinum. All the compounds were found to be antifungal active.
Some of the compounds displayed activities comparable with that of the commercial fungicide Dithane
M-45. Structure-activity relationships for the screened compounds are discussed.
KEYWORDS: Fungicide; oxothiazolidinyl; bibenzyl
INTRODUCTION
sequence leading to the formation of Va-d and VIa-h is out-
lined in Scheme 1. The starting compound benzil I was reduced
to bibenzyl II, which on nitration gave 4,4′-dinitrobibenzyl III.
Reduction of 4,4′-dinitrobibenzyl III by Pd-C and HCOOH
yielded quantitatively and analytically pure 4,4′-diaminobibenzyl
IV. Compound IV on condensation with various carbonyl com-
pounds gave 4,4′-bis (benzylideneamino) bibenzyls Va-f, which
on cycloaddition with mercaptoacetic acid/ mercaptopropionic
acid afforded corresponding 4,4′-bis (2“-aryl-5”-methyl/ un-
subsituted-4′′-oxothiazolidin-3′′-yl) bibenzyl VIa-l.
The structural assignments of the synthesized products were
based on elemental analysis (C, H, N, S, and Cl) and 1H NMR
spectra (Tables 1 and 2). 1H NMR spectral studies have shown
that the synthesis is highly diastereoselective because only one
diastereomer could be obtained. The reduction of dinitro com-
pound III in good yield (90-95%) into corresponding diamino
compounds IV at room temperature was done by HCOOH in
the presence of 10% palladised charcoal (16). The catalyst was
recovered and reused after washing with water and ethanol. The
results indicated that there is no loss of catalytic activity. Of
the tested compounds Va-f and VIa-l, compounds Vc, VIc,
VIf, Vig, VIh, VIk, and VIl displayed in vitro fungitoxicity
comparable to that of the commercial fungicide Dithane M-45
(a mixed Mn2+ and zinc salt of N, N′-ethylenebis (dithiocarbamic
acid)) at 1000 ppm concentration against Fusarium oxysporium
and Penicillium citrinum (Table 3).
The application of thiazolidinones as toxic agents into cells
of pathogenic microorganisms have evoked considerable atten-
tion during the past 20 years (1-3). 4-Thiazolidinones are well-
known for their hypnotic (4) and anticonvulsant (5,6) properties.
The presence of the N-C-S linkage in heterocycles has been
reported to have antitubercular (7), antifungal (8), and antian-
algesic (9) activity. 4-Thiazolidinones have also been shown to
have anti HIV (10) activity.
A literature survey (11-13) have revealed that bryophytes
are not damaged by fungi although they contain nutritious
material like fatty acids, sterols, triglycerides, etc. (11). The
reported reason is the presence in these bryophyte of structural
variants of bibenzyl and bisbibenzyl (13). It has been found
that both natural and synthetic bibenzyl show antifungal activity
against spore germination of Alternaria brassicola, Botrytis
cinerea, Uromyces fabal (13).
The above facts coupled with our desire to develop efficacious
agricultural fungicides prompted us to devise a convenient
synthesis of 4-thiazolidinone derivatives incorporating biben-
zyl moiety hitherto unknown title compounds, 4,4′-bis-(2′′-
aryl-5′′-methyl/unsubstituted-4′′-oxothiazolidin-3′′-yl) bibenzyl
VIa-l. Compounds Va-f are also new ones. The reaction
* To whom correspondence should be addressed. E-mail: irspksjs@
rediffmail.com.
10.1021/jf0342324 CCC: $25.00 © 2003 American Chemical Society
Published on Web 10/22/2003

Synthesis of a Novel Thiazolidinone
J. Agric. Food Chem., Vol. 51, No. 24, 2003 7063
Table 2. Spectral Data of Compounds Va−d and VIa−h
Scheme 1
cpd
1H NMR (CDCl3)δ (J, Hz)
Va
2.85 (4H, s, acyclic CH CH ), 7.21−7.53 (18H, m, ArH),
2
2
8.31 (2H, s, CHdN)
2.86 (4H, s, acyclic CH CH ), 3.95 (6H, s, OCH ),
7.20−7.72 (16H, m, ArH), 8.31 (2H,s,CHdN)
Vb
Vc
Vd
2
2
3
2.86 (4H, s, acyclic CH CH ) 7.24−7.94 (16H, m, ArH),
2
2 ,
8.31 (2H, s, CHdN)
2.87 (4H, s, acyclic CH CH ), 3.93 (6H, s, OCH ),
2
2
3
3.95 (6H, s, OCH ), 7.23−8.10, (14H, m, ArH),
3
8.31 (2H, s, CHdN)
Ve
Vf
2.85 (4H, s, acyclic CH CH ), 7.21−7.53 (16H, m, ArH),
8.31 (2H, s, CHdN), 12.1 (2H, s, ArOH)
2
2
2.85 (4H, s, acyclic CH CH ), 3.93 (6H, s, OCH ),
2
2
3
7.21−7.53 (14H, m, ArH), 8.31 (2H, s, CHdN),
(2.1 (2H, s, ArOH)
VIa
VIb
2.85 (4H, s, acyclic CH CH ), 4.29 (4H, q, cyclic CO−CH −S),
5.95 (2H, s, cyclic S−CH−N), 7.21−7.53 (18H, m, ArH)
2
2
2
2.86 (4H, s, acyclic CH CH ), 3.95 (6H, s, OCH ),
2
2
3
4.29 (4H, q, cyclic CO−CH −S), 5.95 (2H, s,
2
cyclic S−CH−N), 7.20−7.72 (16H, m, ArH)
VIc
VId
2.86 (4H, s, acyclic CH CH ), 4.30 (4H, q, cyclic CO−CH −S),
5.95 (2H, s, cyclic S−CH−N), 7.24−7.95 (16H, m, ArH)
2
2
2
2.87 (4H, s, acyclic CH CH ), 3.93 (6H, s, OCH ),
2
2
3
3.95 (6H, s, OCH ), 4.30 (4H, q, cyclic CO−CH −S),
3
2
5.95 (2H, s, cyclic N−CH−S), 7.20−8.14 (14H, m, ArH).
1.22 (6H, d, J ) 8, CH ), 2.85 (4H, s, acyclic CH CH ),
VIe
VIf
3
2
2
4.20 (2H, q, J ) 8, cyclic CHCH ),
3
5.95 (2H, s, cyclic S−CH−N), 7.21−7.53 (18H, m, ArH)
1.22 (6H, d, J ) 8, CH ), 2.86 (4H, s, acyclic CH CH ),
Table 1. Analytical Data of Compounds Va−f and VIa−l
3
2
2
3.95 (6H, s, OCH ), 4.20 (2H, q, J ) 8, cyclic CHCH ),
3
3
cpd
yield %
mp (deg C)
mol formulaa
C H N
5.95 (2H, s, cyclic S−CH−N), 7.20−7.72 (16H, m, ArH)
1.22 (6H, d, J ) 8, CH ), 2.86 (4H, s, acyclic CH CH ),
Va
b
c
d
e
f
VIa
b
c
d
e
f
g
h
i
j
k
l
67
70
63
58
54
61
85
73
71
90
82
74
76
87
78
73
61
65
168
181
187
204
201
194
191
197
205
201
203
234
227
213
202
207
209
213
28 24
2
VIg
VIh
3
2
2
C H N O
30 28
2 2
4.21 (2H, q, J ) 8, cyclic CHCH ), 5.95 (2H, s,
3
C H N Cl2
28 22
2
cyclic S−CH−N), 7.24−7.91 (16H, m, ArH)
C H N O
32 32
2 4
1.22 (6H, d, J ) 8, CH ), 2.87 (4H, s, acyclic CH CH ),
3
2
2
C H N O
2 2
28 24
3.93 (6H, s, OCH ), 3.95 (6H, s, OCH ), 4.20 (2H, q,
3
3
C H N O
30 28
2 4
J ) 8, cyclic CHCH ), 5.95 (2H, s, cyclic S−CH−N),
C H N O S
32 28 2 2 2
3
C H N O S
7.20−8.14 (14H, m, ArH)
34 32
2 4 2
C H N O S Cl2
VIi
VIj
2.85 (4H, s, acyclic CH CH ), 4.29 (4H, q, cyclic CO−CH −S),
32 26
2 2 2
2
2
2
C H N O S
36 36
2 6 2
5.95 (2H, s, cyclic S−CH−N), 7.21−7.53 (16H, m, ArH),
12.1 (2H, s, ArOH)
C H N O S
2 2 2
34 32
C H N O S
36 36
2 4 2
2.85 (4H, s, acyclic CH CH ), 3.93 (6H, s, OCH ),
2
2
3
C H N O S Cl2
34 30 2 2 2
4.29 (4H, q, cyclic CO−CH −S), 5.95 (2H, s,
2
C H N O S
38 40
2 6 2
cyclic S−CH−N), 7.21−7.53 (14H, m, ArH),
12.1 (2H, s, ArOH)
C H N O S
2 4 2
32 28
C H N O S
34 32 2 6 2
VIk
VIl
1.22 (6H, d, J ) 8, CH ), 2.85 (4H, s, acyclic CH CH ),
3
2
2
C H N O S
34 32 2 4 4
C H N O S
4.20 (2H, q, J ) 8, cyclic CHCH ), 5.95 (2H, s,
36 36
2
6
2
3
cyclic S−CH−N), 7.21−7.53 (16H, m, ArH),
12.1 (2H, s, ArOH)
a Satisfactory elemental microanalyses obtained C ± 0.30, H ± 0.18, N ± 0.24,
S ± 0.16, and Cl ± 0.2.
1.22 (6H, d, J ) 8, CH ), 2.85 (4H, s, acyclic CH CH ),
3
2
2
3.93 (6H, s, OCH ), 4.20 (2H, q, J ) 8, cyclic CHCH ),
3
3
5.95 (2H, s, cyclic S−CH−N), 7.21−7.53 (14H, m, ArH),
12.1 (2H, s, ArOH)
EXPERIMENTAL PROCEDURE
Melting points were determined on to an open glass capillary method
and are uncorrected. Completion of the reaction was monitored by TLC
(silica gel, benzene: ethyl acetate, 8:2). The final products were purified
by column chromatography using silica gel (100 mesh) with increasing
percentage of MeOH in benzene. 1H NMR spectra were recorded on a
Varian FT-20 spectrometer in CDCl3, using TMS as an internal ref-
erence; chemical shifts are expressed in δ values.
Bibenzyl (II). Following the standard reduction procedure (15) I
was treated with Zn-Hg and HCl to yield II.
4,4′-Dinitrobibenzyl (III). It was prepared by nitration of bibenzyl
II following a reported procedure (14). III agreed well with the
analytical data already reported in the literature (14).
zaldehyde (0.01 mole, 1.061 g) and traces of fused ZnCl2. The reaction
mixture was refluxed on water-bath for 30 min and cooled to RT. Excess
of ethanol was distilled-off under reduced pressure. The resultant residue
was taken in 20 mL of chloroform and filtered. The filtrate was
evaporated to give crude Va, which was recrystalized from an ethanol:
water mixture (50 mL, 1:1, v/v). Compounds Vb-f were synthesized
in similar way by using anisaldehyde, veratraldehyde, p-chlorobenzal-
dehyde, salicylaldehyde, and vanilline in place of benzaldehyde,
respectively.
4,4′-bis (2′′-Aryl-5′′-methyl/unsubstituted-4′′-oxo-thiazolidin-3′′-
yl) Bibenzyl (VIa-l). A mixture of Va-f (0.005 mole) and mercap-
toacetic acid/ 2-mercaptopropionic acid (0.01 mole) in dry benzene
was refluxed on a steam bath for 3-4 h. The excess of benzene was
then distilled-off under reduced pressure. The reaction mixture was
poured over crushed ice and centrifuged.
4,4′-Diaminobibenzyl (IV). Dinitro compound III was reduced by
formic acid in the presence of 10% palladium on carbon following the
standard procedure (16) to IV in 95% yield. IV agreed well with the
mp already reported (17).
4,4′-bis (Benzylideneamino) Bibenzyl (Va-f): To a solution of
IV (0.0058 mole, 1.231 g) in dry ethanol (20 mL) was added ben-

7064 J. Agric. Food Chem., Vol. 51, No. 24, 2003
Siddiqui et al.
that of Dithane M-45 at 1000 ppm and inhibited 15-59%
mycelial growth of both fungal species even at the lowest
concentration. Compounds Va-f, which have no oxothiazoli-
dine nucleus are less fungitoxic than VIa, VIb, VIf, VIg, VIh,
and VIi which have 5-methyl oxothiazolidine nucleus. This
demonstrates that the presence 5-methyl oxothiazolidine nucleus
with the bibenzyl nucleus resulted in appreciable enhancement
of fungitoxicity of these compounds.
The present study indicates that the 4,4′-bis(oxo-thiazolidinyl)
bibenzyl framework reported herein might be useful for de-
veloping efficacious fungicides by suitable structural variation
in the bibenzyl nucleus and heterocylic ring.
Table 3. Antifungal Screening Results of Compounds Va−f and VIa−l
Av % inhibition after 96 h against
F. oxysporium
P. citrinum
cpd
Va
b
c
d
e
f
VIa
b
c
d
e
f
g
h
1000 ppm 100 ppm 10 ppm 1000 ppm 100 ppm 10 ppm
50
46
83
55
62
51
55
61
82
38
61
78
100
85
75
71
88
91
100
24
36
47
43
53
47
30
50
43
26
50
65
81
62
65
58
71
85
91
9
29
20
31
25
48
12
24
15
24
39
40
59
41
40
51
30
76
86
56
58
88
42
50
57
51
46
87
67
67
73
100
88
68
63
78
87
100
20
44
30
27
33
45
20
32
33
50
40
56
79
69
42
55
65
58
95
13
21
15
19
23
37
10
17
8
26
25
38
53
45
30
46
37
45
89
ACKNOWLEDGMENT
We sincerely thank Dr. L. D. S. Yadav, Reader, Department of
Chemistry, University of Allahabad, Allahabad, India 211002
for many helpful discussions pertaining to the material in this
article. We are thankful to Dr. Rashmi Sanghi, FEAT, Labs,
IIT, Kanpur, India for spectral studies and elemental analysis
of synthesized compounds.
i
j
k
l
Dithane
M-45
LITERATURE CITED
(1) Jadhav, K. P.; Ingle, D. B. Synthesis of potential fungicidal
compounds. J. Indian Chem. Soc. 1978, 55, 424-426.
(2) Sharma, R. C.; Kumar, D. Synthesis of some new thiazolidin-
4-ones as possible antimicrobial agents. J. Indian Chem. Soc.
2000, 77, 492-493.
(3) Srivastava, S. K.; Srivastava, S. L.; Srivastava, S. D. Synthesis
of 5-arylidene-2-aryl-3- (2- chlorophenothiazinoyacetamidyl)-
1,3-thiazolidin-4-ones as antifugal and anticonvulsant agents. J.
Indian Chem. Soc. 2000, 77, 104-105.
(4) Doran, W. J.; Shonle, H. A. Dialkyl Thiazolidiones. J. Org.
Chem. 1939, 3, 193-197.
(5) Mishra, S.; Srivastava, S. K.; Srivastava, S. D. Synthesis of
5-arylidene-2-aryl-3-(phenothiazino/ benzotriazoloacetamidyl)-
1,3-thiazolidine-4-ones as antiinflammatory, anticonvulsant,
analgesic, and anti-microbial agents. Indian J. Chem. 1997, 36B,
826-830.
The resulting solid was washed with ice-cold saturated aqueous
solution of sodium bicarbonate, dried and recrystalized from methanol
to give yellow colored crystals of VIa-l.
Yields, melting points, molecular formula, and elemental analysis
of compounds Va-f and VIa-l are recorded in Table 1 and spectral
data in Table 2.
Antifungal Screening. In vitro antifungal activity of compounds
Va-f and VIa-l was evaluated against Fusarium oxysporium and
Penicillium citrinum by the poisoned food technique (18) (1000, 100,
and 10 ppm) using Czapek’s agar as medium as previously described
(19, 20). The number of replicate assays in each were three, and six
replicate controls were used. Commercial fungicide, Dithane M-45 was
used as standard. No remarkable morphological change was observed
in the developing fungi. The antifungal screening results are summarized
in Table 3.
For the most active compounds Vc, VIc, Vig, VIh, VIk, and VIl, it
was ascertained whether they are fungistatic or fungicidal. Thus,
following the procedure of Garber and Houston (21), compounds Vc,
VIc, VIg, VIh, VIk, and VIl were added separately to Czapek’s agar
medium in different Petri dishes to maintain the final concentrations
at their lethal dose (800, 900, and 1000 ppm, respectively). The test
fungi were inoculated in the center of these Petri dishes and incubated
at 28 ( 1 °C for 96 h, after which time, the percent inhibition of
mycelial growth compared with that in control dishes was recorded.
Then, the fungal disks were taken from the treated and control dishes,
washed with sterilized double-distilled water, and reinoculated in fresh
Petridishes containing Czapek’s agar medium only. The plates were
incubated for 96 h at 28 ( 1 °C and the percent inhibition was recorded.
The number of replicate assays in each case was three, and six replicate
controls were used.
(6) Troutman, H. D.; Long, L. M. The Synthesis of 2,3-Disubsti-
tuted-4-thiazolidones. J. Am. Chem. Soc. 1948, 70(10), 3436-
3439.
(7) Oza, H.; Joshi, D.; Parekh, H. Synthesis and antitubercular
activity of novel thiazolidinone derivatives. Indian J. Chem.
1998, 37B, 822-824.
(8) Singh, S. R. 4-Thiazolidinones: Synthesis and fungicidal activity
of 5-methyl-3-aryl-2-arylimino-4-thiazolidinones and their Ace-
toxymercuric derivative. J. Indian Chem. Soc. 1976, 53, 593-
597.
(9) Srivastava, S. K.; Srivastava, S.; Srivastava, S. D. Synthesis of
2-aryl-3-(N9-carbazolylacetamidyl)-4-oxothiazolidines and their
5-arylidines as antifungal and analgesic agents. J. Indian Chem.
Soc. 2001, 78, 320-322.
(10) Joshi, H. D.; Upadhyay, P. S.; Baxi, A. J. Studies on 4-thiazo-
lidinones: Synthesis and pharmacological activity of 1,4-bis [2′-
methyl/ethyl-2′-substituted styryl-5′-H/methyl/carboxymethyl-
4′-thiazolidinon-3′-ylamino] phthalazines. Indian J. Chem. 2000,
39B, 967-970.
(11) Pavletic, Z.; Stilionic, B. Untersuchungen u¨ber die antibiotische
wirkung von moosextrakten aut enige Bakterien. Acta Bot.
Croatica 1963, 22, 133.
The plates were incubated for 96 h at 28 ( 1 °C and the percent
inhibition was recorded. The number of replicate assays in each case
was three, and six replicate controls were used. It was found that
compounds Vc, VIc, VIg, VIh, VIk, and VIl caused complete inhibition
of mycelial growth of the test fungi in treated as well as reinoculated
dishes and hence were fungicidal.
RESULTS AND DISCUSSION
(12) Gorham, J. Lunularic acid and related compounds in liver-
worts, algae, and hydrangea. Phytochemistry 1977, 16, 249-
253.
(13) Pryce, R. J. Metabolism of lunularic acid to new plant stil-
bene by Lunularia cruciata. Phytochem. 1972, 11, 1355-
1364.
Most of the screened compounds have significant fungitox-
icity at (1000 ppm) (Table 3) against both tested fungi, but
their toxicity considerably decreased on dilution (100 and 10
ppm). Of the tested compounds, the most active benzylidene-
amino bibenzyl Vc and oxothiozolidinyl bibenzyl VIc, VIg,
VIh, VIk, and VIl displayed fungicidal action comparable with
(14) Rinkenbach, W. H.; Aaronson, H. A. The nitration of sym-
diphenylethane. J. Am. Chem. Soc. 1930, 52, 5040-5045.

Synthesis of a Novel Thiazolidinone
J. Agric. Food Chem., Vol. 51, No. 24, 2003 7065
(15) Martin, E. L.; Adams, R. Organic Reaction, 4th reprint; John
Wiley: London, 1947; I, p 181.
(16) Gowda, D. C.; Gowda, S. Formic acid with 10% palladium on
carbon: A reagent for selective reduction of aromatic nitro
compounds. Indian J. Chem. 2000, 39B, 709-711.
(17) Fuson, C. R.; House, H. O. Heterocycles containing p-phenylene
units. I. Ethers. J. Am. Chem. Soc. 1953, 75, 1325-1327.
(18) Horsfall, J. G. Quantitative bioassay of fungicides in the
laboratory. Bot. ReV. 1945, 11, 357-397.
(19) Yadav, L. D. S.; Misra, A. R.; Singh, H. Synthesis of new 7H-
1,3,4-thiadiazolo [3,2-a] [1, 3, 5] triazine-7-thiones as potential
fungicides. Pestic Sci. 1989, 25, 219-225.
(21) Garber, R. H.; Houston, B. R. An inhibitor of Verticillium
alboatrum in cotton seed. Phytophthology 1959, 49, 449-450.
(22) Dikshit, D. K.; Munshi, R.; Kapil, R. S.; Anand, N.; Van Der
Veen, J. M.; Fujiwara, H. Synthesis of Diastereomers of 4,5-
Dihydro-3,4,5-triphenylfuran-2(3H)-one. Indian J. Chem. 1977,
15B, 977-980.
(23) Rajanarendar, E.; Afazal, M.; Ramu, K. Synthesis of isoxazolyl
oxadiazolines and thiazolidinones. Indian J. Chem. 2003, 42B,
927-930.
Received for review March 10, 2003. Revised manuscript received
September 3, 2003. Accepted September 15, 2003.
(20) Yadav, L. D. S.; Tripathi, R. L.; Dwivedi, R.; Singh, H. Synthesis
of new 1,3,4-oxadiazolo [3,2-d] thiadiazines with fungicidal
action. J. Agric. Food Chem. 1991, 39, 1863-1865.
JF0342324