Reaction with hydrazonoyl halides. Part 32 [1]: Reaction of C-acyl-N-(3-phenyl-5-pyrazolyl)hydrazonoyl chlorides with potassium thiocyanate and synthesis of some new 2,3-dihydro-1,3,4-thiadiazoles and slenadiazoles

Article abstract of DOI:10.1002/hc.1071

C-acyl-N-(3-phenyl-4-pyrazolyl)hydrazonoyl chlorides 1a,b react with potassium thiocyanate and potassium selenocyanate to give (5-acyl-2,3-dihydro-2-imino-3-(3′-phenyl)pyrazol-5′-yl)-1,3,4-thiadi azoles 2a,b and (5-acetyl-2-3-dihydro-2-imino-3-(3′-phenyl)

Full text of DOI:10.1002/hc.1071

Heteroatom Chemistry
Volume 12, Number 6, 2001
Reaction with Hydrazonoyl Halides. Part 32
[1]: Reaction of C-acyl-N-(3-Phenyl-5-
pyrazolyl)hydrazonoyl Chlorides with
Potassium Thiocyanate and Synthesis of Some
New 2,3-dihydro-1,3,4-Thiadiazoles and
Slenadiazoles*
Abdou O. Abdelhamid, M. M. M. Sallam, and S. A. Amer
Department of Chemistry, Faculty of Science, Cairo University, Giza 12613, Egypt
Received 14 August 2000; revised 29 January 2001
been examined [6] and give exclusively pyrazolo[5,1-
ABSTRACT:
C-acyl-N-(3-phenyl-5-pyrazolyl)hy-
drazonoyl chlorides 1a,b react with potassium thio-
cyanate and potassium selenocyanate to give 5-acyl-
2,3-dihydro-2-imino-3-(30-phenyl)pyrazol-50-yl)-1,3,
4-thiadiazoles 2a,b and 5-acetyl-2,3-dihydro-2-imino-
3-(30-phenyl)pyrazol-50-yl)-1,3,4-selenadiazole 10a,b.
Also, 2-[mercapto-(methylthio)methylene]indan-1,3-
dione 16 reacts with hydrazonoyl halides 15 and 22–
25 to afford 2,3-dihydro-1,3,4-thiadiazoles 19 and 26–
29, respectively. Structures of the newly synthesized
compounds are elucidated on the basis of spectral
data, chemical transformations, and alternative syn-
C
c] triazines 3. The formation of 5-acyl-2,3-dihydro-2-
imino-3-pyrazol-30-yl-1,3,4-thiadiazole 2, although
expected in principle, was not observed. In the pres-
ent study, we investigated this reaction, and we iso-
lated 5-acyl-2,3-dihydro-2-imino-3-(30-phenyl)pyra-
zol-50-yl)-1,3,4-thiadiazoles as the sole product in
each case and in about 80% yield. Structures were
supported by both spectral data and chemical trans-
1
formations. Thus, the IR (cm ) spectrum 2a re-
vealed bands at 3306 due to the imino (NH) group,
1653 (CO), 1618 (C N), and no band at 2000–2200
showing the absence of a free SCN group [7]. Its 1H
NMR spectrum showed signals at = 2.51 (s, 3H,
CH3CO), 6.49 (s, 1H, pyrazole C-4), 7.20–7.59 (m, 6H,
ArHs and NH), and 10.82 (s, br., 1H, NH). Upon
shaking compound 2a with D2O, a new singlet at
4.38 assignable to DOH was observed. Unequivocal
support of the structure of 2a was further confirmed
by treatment of 5-phenylpyrazole-3-diazonium chlo-
ride with 3-thiocyanato-2,4-pentandione (8a) [8] in
ethanolic sodium acetate to produce a product that
proved to be identical in all respects (m.p., mixed
m.p., and spectra) with 2a (cf. Scheme 1).
thesis methods.
Heteroatom Chem 12:468–474, 2001
2001 John Wiley & Sons, Inc.
The reported biological activity of 1,3,4-thiadiazoles
[1–5] makes them attractive targets for synthesis.
The reactions between C-acyl-N-pyrazolylhydrazo-
noyl bromides and potassium thiocycyanate have
*Part 31: Abdelhamid, A. O.; Zohdi, H. F.; Sallam, M. M. M.,
Ahmed, A. A. Molecules 2000, 5, 967.
Nitrosation of the imino derivative 2a gave a 2-N-
nitroso derivative 4a. The structure of 4a was con-
firmed on the basis of elemental analyses, spectral
Correspondence to: Abdou O. Abdelhamid. E-mail: Abdou@
main-scc.cairo.eun.eg
c
2001 John Wiley & Sons, Inc.
468

Reaction with Hydrazonoyl Halides 469
anate proceed through the hydrazone 9. The latter is
cyclized readily under the reaction conditions to give
5-acetyl-2-imino-2,3-dihydro-50-phenylpyrazol-30-yl-
1,3,4-thiadiazole (2a).
Also, C-ethoxycarbonyl-N-(5-phenyl)pyrazol-3-
ylhydrazonoyl chloride (1b) reacted with potassium
thiocyanate in ethanol at room temperature to afford
5-ethoxycarbonyl-2, 3-dihdro-2-imino-3-(50-phenyl)
pyrazol-30-yl-2,3-dihydro-1,3,4-thiadiazole (2b). The
structure was elucidated on the basis of elemental
analysis, spectral data, and chemical reactions (ac-
ylation, nitrosation, thermal decomposition of the
nitroso product) (cf. Scheme 1 and Experimental
section).
Moreover, hydrazonoyl chlorides 1a,b reacted
with potassium selenocyanate to afford 2,3-dihydro-
1,3,4-selenadiazoles 10a,b. Structure 10a was eluci-
dated on the basis of spectral data, chemical trans-
formation, and an alternative synthesis (by coupling
of diazotized aminopyrazole with 3-selnocyanato-
2,4-pentane dione (8b) [8] (cf. Scheme 3 and Exper-
imental section).
SCHEME 1
Next, the reaction of C-ethoxycarbonyl-N-phen-
ylhydrazonoyl chloride 15a with 2-[mercapto-
(methylthio)methylene]indan-1,3-dione 16 [9] in the
presence of triethylamine gave 2,3-dihydro-1,3,4-
thiadiazole 19a. The structure was deduced from its
data, and its thermal decomposition. Thus, the
IR (cm ) spectrum of 4a revealed bands at 3310
1
(NH), 1660 (CO), and 1530 (NO). The 1H NMR spec-
trum of 4a showed signals at = 2.51 (s, 3H, CH3CO),
6.56 (s, 1H, pyrazole C-4), 7.20 –7.59 (m, 5H, ArHs),
and 10.82 (s, br, 1H, NH). The nitroso derivative 4a
decomposed to the corresponding 2,3-dihydrothiadi-
azolone 5a, when heated in a refluxing xylene solu-
tion. The structure of 5a was confirmed on the basis
1
spectra and elemental analysis. The IR (cm ) spec-
trum revealed bands at 1741, 1697, 1645 (COs), and
1
1593 (C C). Its H NMR spectrum showed signals
at = 1.44 (t, 3H, CH3CH2), 4.53 (q, 2H, CH2CH3),
and 7.25–7.57 (m, 9H, ArHs). The structure 19 was
further confirmed by the reaction of hydrazonoyl
chloride 15a with thioanilide 20 (which was pre-
pared from 1,3-indandione and phenyl isothiocya-
nate) in N,N-dimethylformamide solution contain-
ing potassium hydroxide to give a product identical
in all respects (m.p., mixed m.p. and spectra) with
19a (cf. Scheme 4). The formation of thiadiazole 19
can be explained on the basis of the elimination of
methanthiol from the cycloadduct 18, which is as-
sumed to be formed by a 1,3-dipolar cycloaddition
of the nitrile imide (generated in situ by treatment
of 15a with triethylamine) to the C S double bond
of 16 or by a stepwise path involving substitution via
a 1,3-addition of thiol 16 to the nitrile imide to give
a cyclic hydrazone 17, which was transformed into
the cyclic intermediate 18. Cyclization of the latter
could be achieved by elimination of methanthiol to
afford the final product 19.
1
of analytical and spectral data studies. The IR (cm )
spectrum of 5a revealed absorption bands at 3340
1
(NH), 1690, 1653 (COs) groups. The H NMR spec-
trum of 5a showed signals at = 2.52 (s, 3H,
CH3CO), 6.56 (s, 1H, pyrazole C-4), 7.20–7.58 (m, 5H,
ArHs), and 10.82 (s, 1H, NH). Acylation of 2a with
acetic anhydride (and benzoyl chloride in pyridine)
afforded the corresponding acetyl and benzoyl de-
rivatives 6a and 7b, respectively (cf. Scheme 1). Both
elemental analyses and spectral data were consistent
with the assigned structure of the products 6a and
1
7a. The H NMR spectrum of 6a showed signals at
= 2.52 (s, 3H, CH3CO), 2.72 (s, 3H, CH3CON = ),
6.61 (s, 1H, pyrazole C-4), 7.22–7.51 (m, 5H, ArHs)
1
and 10.56 (s,br1H,NH). Its IR(cm )spectrum
revealed bands at 1664 and 1638 (COs). The 1H
NMR spectrum of 7a showed signals at = 2.51
(s, 3H, CH3), 6.60 (s, 1H pyrazole C-4), 7.22–7.81
(m, 10H, ArHs), and 10.84 (s, br, 1H, NH). Its IR
It is worthwhile to mention that the elimination
of aniline by the reaction of thioanilide 20 with hy-
drazonoyl chloride 15a came about from the thioan-
ilide, based on comparison spectral data with the
product obtained from the reaction of thioanilide 20
1
(cm ) spectrum revealed bands at 1661 and 1640
(CO groups).
Such results indicate that both the azo coupling
of 8a and the reaction of 1a with potassium thiocy-

470 Abdelhamid, Sallam, and Amer
SCHEME 2
SCHEME 3

Reaction with Hydrazonoyl Halides 471
SCHEME 4
with C-ethoxycarbonyl-N-p-tolylhydrazonoyl chlo-
ride (15b) (cf. Scheme 4). Thus, The H NMR spec-
[6], 15 [10], and 22–25 [11–14] were prepared as pre-
viously reported.
1
trum of 19b showed signals at = 1.44 (t, 3H,
CH3CH2), 2.45 (s, 3H, 4-CH3C6H4), 4.52 (q, 2H,
CH3CH2),and7.22–7.58(m, 8H, ArHs). Similarly, the
2-[mercapto(methylthio)methylene]indan-1,3-dione
(16) reacted with hydrazonoyl halides 22–25 in
ethanolic triethylamine to give the corresponding
2,3-dihydro-1,3,4-thiadiazoles 26–29, respectively
(cf. Scheme 4).
Synthesis of 5-Acyl-2,3-dihydro-2-imino-3-(30-
phenyl) pyrazol-50-yl)-1,3,4-thiadiazole and 5-
Acetyl-2,3-dihydro-2-imino-3-(30-phenyl)pyrazol-
50-yl)-1,3,4-selenadiazole (2a,b) and 10a,b
Method A A mixture of the appropriate C-acyl-
N-5-phenylpyrazol-3-ylhydrazonoyl chloride (1a,b)
and potassium thiocyanate (or potassium seleno-
cyanate) (5 mmol) in ethanol (25 mL) was stirred at
room temperature for 2 hours. The resulting solid
was collected and crystallized from ethanol to give
the thiadiazole 2a,b and the selenadiazole 10a,b,
respectively.
EXPERIMENTAL
All melting points were determined on an electro-
thermal apparatus and are uncorrected. IR spectra
were recorded (KBr discs) on a Shimadzu FT-IR
1
8201 PC spectrophotometer. H NMR spectra were
recorded in CDCl3 and (CD3)2SO solutions on a Var-
ian Gemini 300 MHz spectrometer, and chemical
shifts are expressed in units using tetramethylsi-
lane (TMS) as an internal reference. Elemental anal-
yses were carried out at the Microanalytical Center
of the Cairo University. Hydrazonoyl bromides 1a,b
Method B Diazotized 3-amino-5-phenylpyra-
zole [15] (5 mmol) was added to ethanol (50 ml)
containing sodium acetate (1.3 g) and 3-thiocyanato-
(or 3-selenacyanato)-2,4-pentanedione (5 mmol) at
0–5 C with stirring. Stirring was continued for
3 hours, and then the resulting solid was collected by

472 Abdelhamid, Sallam, and Amer
TABLE 1 Characterization Data of the Newly Synthesized Compounds
% Analyses, Calcd./Found
Compound No.
2a
m.p. ( C) Color
Yield (%)
85
80
91
89
87
89
88
90
89
91
85
78
92
63
73
82
79
85
81
82
78
87
81
84
79
86
76
74
Mol. Formula Mol. Wt
%C
%H
%N
%S
197–98
Yellow
180–82
Yellow
142–43 dec
Red
134–35 dec
Red
215–16
Pale yellow
165–67
Pale yellow
195–96
Pale yellow
213–14
Pale yellow
284–85
Buff
220–22
Pale yellow
179
Pale yellow
145–147
Yellow
132 dec.
Red
134 dec.
Red
187–88
Pale yellow
197–98
Pale yellow
174–6
Pale yellow
254–5
Pale yellow
257–58
Yellow
245–48
Yellow
312–14
Yellow
322–25
Yellow
C13H11N5OS
285.33
54.72
54.60
53.32
53.20
49.68
49.80
48.83
48.90
54.54
54.40
53.16
53.00
55.04
55.00
53.77
53.50
61.68
61.80
60.13
60.10
47.00
46.80
46.42
46.40
43.23
43.30
42.98
43.10
46.86
46.60
48.14
48.20
47.53
47.30
55.05
54.90
63.48
63.60
64.27
64.20
67.75
67.60
68.32
68.20
65.51
65.70
66.28
66.10
70.23
70.30
70.74
70.90
65.99
65.80
66.66
66.50
3.89
4.10
4.16
4.20
3.21
3.40
3.51
3.40
3.52
3.70
3.82
3.90
4.00
4.20
4.23
3.30
3.88
3.90
4.09
3.90
3.34
3.50
3.62
3.50
2.79
2.60
3.09
3.20
3.03
3.10
3.50
3.60
3.74
3.60
3.74
3.60
3.73
3.60
4.11
4.00
3.55
3.70
3.90
3.80
3.47
3.60
3.89
4.00
3.44
3.30
3.80
3.90
3.02
3.10
3.40
3.30
24.54
24.30
22.21
22.40
26.74
26.60
24.41
24.60
19.57
19.70
17.71
17.60
21.39
21.10
19.60
19.70
17.98
18.10
16.70
16.50
21.08
21.20
19.33
19.10
23.27
23.40
21.48
21.60
16.81
17.00
18.71
18.60
17.32
17.30
16.05
16.20
7.40
7.50
7.14
6.90
9.88
10.10
9.56
9.60
8.04
7.80
7.73
7.60
6.82
6.90
6.60
6.50
7.00
6.90
11.24
11.40
10.17
10.00
10.20
10.30
9.31
9.50
11.20
11.00
10.14
10.30
9.79
9.90
8.97
8.80
8.23
8.40
7.64
7.40
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
8.47
8.30
8.17
8.30
7.54
7.40
7.29
7.10
9.20
9.40
8.85
8.70
7.81
7.90
7.55
7.40
8.01
8.20
7.74
7.80
2b
C
C
C
C
C
C
C
C
C
C
14H13N5O2S
315.36
13H10N6O2S
314.33
14H12N6O3S
344.35
13H10N4O2S
286.31
14H12N4O3S
316.34
15H13N5O2S
327.37
16H15N5O3S
357.39
20H15N5O2S
389.44
21H17N5O3S
419.47
13H11N5OSe
332.23
4a
4b
5a
5b
6a
6b
7a
7b
10a
10b
11a
11b
12
C
C
C
C
C
C
C
14H13N5O2Se
362.25
13H10N6O2Se
361.22
14H12N6O3Se
391.25
13H10N4O2Se
333.21
15H13N5O2Se
374.26
16H15N5O3Se
404.29
20H15N5O2Se
436.33
13
13b
14
19a
19b
26a
26b
27a
27b
28a
28b
29a
29b
C20H14N2O4S
378.41
C21H16N2O4S
392.44
C
C
C
C
C
C
C
C
24H15N3O3S
425.47
25H17N3O3S
439.50
19H12N2O3S
348.38
20H14N2O3S
362.41
24H14N2O3S
410.45
25H16N2O3S
424.48
22H12N2O4S
400.42
23H14N2O4S
414.44
297–98
Yellow
326–27
Yellow
266–68
Yellow
315–18
Yellow
153–54
Yellow
>330
6.76
6.60
Yellow

Reaction with Hydrazonoyl Halides 473
TABLE 2 IR and 1H NMR Spectra of the Newly Synthesized Compounds
Compound
No.
1
IR (cm
)
1H NMR ( ppm)
2b
3306 (NH), 1715 (CO), and
1615 (C N).
3320 (NH), 1715 (CO), and
1535 (NO).
1.31 (t, 3H, CH2CH3), 4.43 (q, 2H, CH2 CH3) 6.51(s, 1H, pyrazole C-4),
7.21–7.56 (m,6H, ArHs and NH) and 10.82 (s, br., 1H, NH).
1.34 (t, 3H, CH2CH3 ), 4.22 (q, 2H, CH2CH3), 6.52 (s, 1H, pyrazole C-4),
7.21–7.55 (m, 5H, ArHs) and 10.62 (s, br, 1H, NH).
4b
5b
3327 (NH), 1715, and 1695
(COs).
1.41 (t, 3H, CH2CH3 ), 4.21 (q, 2H, CH2 CH3), 6.43 (s, 1H, pyrazole C-4),
7.21–7.54 (m, 5H, ArHs) and 10.33 (s, 1H, NH).
6b
3330 (NH), 1713, and 1655
(COs)
3335 (NH), 1715, and 1660
(COs)
1.30 (t, 3H, CH2CH3 ), 2.53 (s, 3H, CH3CON ), 4.42 (q, 2H, CH2CH3 ), 6.60
(s, 1H, pyrazole C-4), 7.21–7.56 (m, 5H, ArHs) and 10.82 (s, br, 1H, NH).
1.32 (t, 3H, CH2CH3 ), 4.21 (q, 2H,CH2 CH3 ), 6.45(s, 1H, pyrazole C-4),
7.21–7.85 (m, 10H, ArHs)and 10.62 (s, br, 1H, NH).
7b
10a
10b
12a
13a
14a
26a
26b
27a
27b
28b
3306 (NH), 1653 (CO), 1618
(C N)
3306 (NH), 1715 (CO), and
1615 (C N).
2.51 (s, 3H, CH3CO), 6.44 (s, H, pyrazole C-4),7.49–7.87 (m, 6H, ArHs and
NH) and 10.82 (s, br, 1H, NH).
1.31 (t, 3H, CH2CH3 ), 4.43 (q, 2H, CH2CH3) 6.51 (s, 1H, pyrazole C-4),
7.21–7.56 (m, 6H, ArHs and NH) and 10.82 (s, br, 1H, NH).
2.52 (s, 3H, CH3CO), 6.56 (s, 1H, pyrazole C-4), 7.20–7.58 (m, 5H, ArHs)
and 10.32 (s, 1H, NH).
2.52 (s, 3H, CH3CO), 2.72 (s, 3H, CH3CON ),6.64 (s, 1H, pyrazole C-4),
7.42–7.87 (m, 5H, ArHs) and 10.89 (s, br, 1H, NH).
2.52 (s, 3H, CH3), 6.65 (s, 1H pyrazole C-4), 7.42–7.81 (m, 10H, ArHs) and
10.91 (s, br, 1H, NH).
3340 (NH), 1690, 1653 (COs)
3340 (NH), 1664, and 1638
(COs).
3340 (NH), 1661, and 1640
(COs).
3350 (NH), 1695, 1680, 1652
(COs) and 1600 (C C).
3342 (NH), 1690, 1685, 1655
(COs) and 1595 (C C)
1695, 1655, 1652 (COs) and
1600 (C C).
1694, 1660, 1653 (COs) and
1600 (C C).
1990, 1665, 1652 (COs) and
1600 (C C)
7.21–7.82 (m, 14H, ArHs) and 8.34 (s, 1H, NH).
2.39 (s, 3H, 4-CH3C6H4), 7.23–7.81 (m, 13H, ArHs) and 8.41 (s, br, 1H, NH).
2.22 (s, 3H, CH3CO), and 7.21–7.83 (m, 14H, ArHs).
2.21 (s, 3H, CH3CO), 2.41 (s, 3H, 4-CH3C6 H4) and 7.15–7.82 (m, 13H,
ArHs).
2.38 (s, 3H, 4-CH3C6H4) and 7.23–8.12 (m, 13H, ArHs).
filtration. The crude product was crystallized from
ethanol to give a products identical in all respects
(m.p., mixed m.p., and spectra) with the compound
obtained by method A.
refluxing, conditions and the solution was evapo-
rated under reduced pressure. The residual oil in
each case was triturated with petroleum ether (40–
60 C), and the resulting solid was collected and crys-
tallized from acetic acid to give 2,3-dihydro-1,3,4-
thiadiazolonones 5a,b and 12a, respectively.
Nitrosation of 2a,b and 10a,b
A saturated solution of NaNO2 (10 mL) was added
dropwise to a solution of the appropriate 2,3-dihy-
dro-1,3,4-thiadiazole 2a,b or 2,3-dihydro-1,3,4-se-
lenadiazole 10a,b (1 g) in acetic acid (20 mL) with
stirring at 0–5 C. The red precipitate in each case
was collected, washed with water, and crystallized
from ethanol, to give a 5-acyl-2,3-dihydro-2-N-
nitroso-3-(30-phenyl)pyrazol-50-yl)-1,3,4-thiadiazole
Acylation of 2a,b and 10a
The appropriate 2a,b and 10a (1 g) was boiled with
acetic anhydride (10 mL) for 5 minutes and poured
onto crushed ice (10 g). The resulting solid was col-
lected, washed, and then crystallized from acetic
acid to give the N-acetyl derivatives 6a, 7a, and 13a,
respectively. An equimolar amount of each 2a,b and
10a and benzoyl chloride in pyridine was refluxed
for 5 minutes, poured onto ice-cold water, and acidi-
fied with hydrochloric acid. The solid was collected,
washed with hot water, and then crystallized from
N,N-dimethylformamide to afford N-acetyl- and N-
benzoyl derivatives 6b, 7b, and 14a, respectively.
(4a,b)
and
5-acetyl-2,3-dihydro-2-imino-3-(30-
phenyl)pyrazol-50-yl)-1,3,4-selenadiazole
respectively.
(11a,b),
Decomposition of 4a,b and 11a
The appropriate N-nitroso derivative 4a,b or 11a (1
g) in xylene (10 mL) was heated for 10 minutes under

474 Abdelhamid, Sallam, and Amer
[4] Reckitt and Colman Products Ltd. German Patent
2727 146, 1978; Chem Abstr 1978, 88, 105357.
[5] Inst Phys Chem Res. Jpn Kokai 77 25 028, 1977;
Chem Abstr 1977, 87, 147054.
[6] Elnagdi, M. H.; Elmoghayar, M. R. H.; Kandeel,
E. M., and Ibrahim, M. K. A. J Heterocycl Chem 1977,
14, 227.
Syntheses of 2,3-Dihydro-1,3,4-thiadiazoles 19,
26–29 (a,b)
Equimolar amounts of indane-1,3-dione, potassium
hydroxide and carbon disulfide (5 mmol, each) in
N,N-dimethylformamide (15 mL) was stirred at
room temperature for 3 hours until the potassium
hydroxide dissolved, and then methyl iodide (0.5
mL) was added. Each hydrazonoyl halide 15, 22–25
(a,b) (5 mmol) was added to the solution with stir-
ring and then triethyamine (0.75 mL) was added.
The resulting solid was collected, washed, and then
crystallized from acetic acid to afford thiadiazoles 19
and 26–29 (a,b), respectively.
[7] Williams, D. H.; Fleming, I. ”Spectroscopic Meth-
ods in Organic Chemistry”, McGraw-Hill Company.
(U.K.), 2nd Edn., (1973).
[8] Yoshida, Z.; Ogoshi, H.; Tokumitsu, T. Tetrahedron
1970, 26, 5691.
[9] Tominago, Y.; Hajime, N.; Matsuda, Y.; Kobayashi, G.
Yakugaku Zasshi 1983, 103, 1243; Chem Abstr 1984,
100, 209677d.
[10] Favrel, G.; Chrz, J. Bull Soc Chim France 1927, 41,
1603.
[11] Favrel, G.; Justoni, R. Gazz Chem Ital 1937, 67, 3.
[12] Shawali, A. S.; Osman, A. Tetrahedron 1971, 27, 2528.
[13] Eweiss, N. F.; Osman, A. J Heterocycl Chem 1980, 17,
1713.
[14] Shawali, A. S.; Abdelhamid, A. O. Bull Chem Soc Jpn
1976, 49, 321.
[15] Elnagdi, M. H.; Elmoghayer, M. R. H.; Fleita, D. H.;
Hafez, A. A.; Fahmi, S. M., J Org Chem 1976, 41,
3781.
REFERENCES
[1] Lubrizol Corp. U.S. Patent 42 46126, 1981; Chem
Abstr 1981, 94, 142505.
[2] Schering, A. G. German Patent 2853 196 1980; Chem
Abstr 1980, 93, 220754.
[3] Akad Wissen DDR. German (East) Patent 136 963,
1979; Chem Abstr 1980, 92, 41963.