Fused triazines via a tandem Wittig/ring closure strategy: Synthesis of pyrazolo[5,1-c]-1,2,4-triazines and 1,2,4-triazolo[5,1-c]-1,2,4-triazines

Article abstract of DOI:10.1002/jccs.200300169

A new method for the synthesis of azolo[5,1-c]-1,2,4-triazine ring systems is reported by the sequential formation of triazine ring based on the regioselective formation of the azophosphoranes from hydrazonyl chlorides, followed by the intermolecular Witt

Full text of DOI:10.1002/jccs.200300169

Journal of the Chinese Chemical Society, 2003, 50, 1189-1194
1189
Fused Triazines Via a Tandem Wittig/Ring Closure Strategy: Synthesis of
Pyrazolo[5,1-c]-1,2,4-triazines and 1,2,4-triazolo[5,1-c]-1,2,4-triazines
Magda A. Barsy
Department of Chemistry, Faculty of Science, South Valley University, Aswan 81528, Egypt
A new method for the synthesis of azolo[5,1-c]-1,2,4-triazine ring systems is reported by the sequential
formation of triazine ring based on the regioselective formation of the azophosphoranes from hydrazonyl
chlorides, followed by the intermolecular Wittig reaction with carboxylic acid chlorides, phenylisocyanate,
and carbon disulfide.
Keywords: Hydrazonylchloride; Azophosphorane; Azolotriazines.
The considerable biological and medicinal activities of
pyrazolotriazines and triazolotriazines, as adenine ana-
logues, antagonists, antischistosomal and antitumor agents1-4
have stimulated recent interest in the synthesis of these ring
systems. In our previous work,5 we reported the synthesis of
azolo- and triazolo[5,1-c][1,2,4]triazepines starting from
azophosphoranes 3 derived from hydrazonyl chlorides 1 and
2. It has been our interest to examine this method and its ap-
plication to the synthesis of new azolo[5,1-c]-1,2,4-triazine
derivatives. 3 reacted smoothly with acyl chlorides in anhy-
drous toluene in the presence of triethylamine (2.0 equiv.) at
room temperature to provide the expected azolotriazine de-
rivatives 5. Here, the tertiary amine seems to be essential for
the reaction as demonstrated. In fact, without Et3N only 9%
product was obtained.
7a-d. The yield of the isolated products was higher than 85%.
We believe that the mechanism of this conversion involves an
initial Wittig reaction between the azophosphoranes 3 and
the phenylisocyanate to furnish a carboimide 6 as highly re-
active intermediate, which easily undergoes a heterocyclic
ring closure to give the fused triazines 7.
The treatment of azophosphoranes 3 with excess of car-
bon disulfide in dry methylene chloride at room temperature,
under nitrogen atmosphere, leads to the formation of azolotri-
azines 9a-d. The possible intermediate 8 in the conversion 8
® 9 is shown in Scheme I. Isolation of this intermediate was
not successful.
We were interested to see if this procedure might be ex-
tended to include other heterocycles, thus hydrazonyl chlo-
rides 11a, b6 were treated with triphenylphosphine and tri-
ethylamine under the same reaction conditions. No expected
azophosphoranes 12a, b were found and pyrazolo[3,4-c]pyr-
azole derivatives 13a, b were isolated instead (Scheme II).
This result showed that azophosphorane 12 is a highly reac-
tive and not isolable compound which, upon formation, un-
dergoes immediate intramolecular cyclization through the
nucleophillic attack of the -N=N- group on the carbonyl
group of compound 12, and subsequent ethanol elimination
would give 13.
R
R
NHN
NH
NHN
NH
N
Cl
Cl
Ph
N
1
N
2
The azophosphoranes 3 apparently act as Wittig re-
agents and azolyl chlorides 4 are assumed to be the key inter-
mediate for the consecutive reaction. The driving force in this
reaction is the formation of the stable phosphine oxide, which
is an inevitable product in the Wittig reactions. Subsequent
cyclization of intermediate 4 by intramolecular nucleophilic
attack of the ring nitrogen to the newly generated electro-
philic carbon center would give the corresponding azolo-
[5,1-c]-1,2,4-triazine derivatives 5a-h (Scheme I).
The -N=N- group in these compounds, in fact, has
shown a great propensity to react as a nucleophile,7 and par-
ticularly is able to proceed intramolecular nucleophilic attack
on electron-deficient carbon atoms located at the ortho posi-
tion on the aromatic ring.8,9
In conclusion, the synthetic method presented herein
provides a new and general route to fused triazines with vari-
able substituents from readily available precursors with high
yield under mild reaction conditions. Further studies along
Azophosphoranes 3 reacted also with phenylisocyanate
in dry toluene at reflux temperature to give azolotriazines

1190 J. Chin. Chem. Soc., Vol. 50, No. 6, 2003
Barsy
Scheme I Reagents and conditions: a) R3COCl/Et3N/toluene, 6-12 h; b) PhNCO/toluene, reflux; c) CS2/CH3CN/
nitrogen gas, 6 h. r.t.
these lines are in progress at our laboratory.
reference. Mass spectra were recorded on a GC MS-QP 1000
EX Shimadzu mass spectrometer at 70 eV. Elemental analy-
sis was carried out at the Microanalytical Center of Cairo
University, Giza, Egypt.
EXPERIMENTAL
Melting points were determined on a Gallenkamp elec-
trothermal melting point apparatus and are uncorrected. IR
spectra were recorded as potassium bromide pellets on a Pye
Unicame SP 3-300 and FT IR 8101 PC Shimadzu infrared
General procedure for the preparation of 4-[aryl (or
alkyl)-7-phenyl-3-substituted pyrazolo[5,1-c][1,2,4]tri-
azines 5a-d and 4-[aryl (or alkyl)-3-substituted-1,2,4-
triazolo[5,1-c][1,2,4]triazines 5e-h
1
spectrophotometer. The H NMR spectra were obtained in
To a solution of azophosphorane 3a-d (0.60 mmol) in
dry toluene (10 mL) was added dropwise appropriate acyl
chloride (benzoyl chloride or acetyl chloride) (1.20 mmol,
deuterated dimethyl sulfoxide on a Varian Gemini 200 NMR
spectrometer using tetramethylsilane (TMS) as an internal

Fused Triazines Via a Tandem Wittig/Ring Closure Strategy
J. Chin. Chem. Soc., Vol. 50, No. 6, 2003 1191
Scheme II Reagents and conditions: d) NaNO2/HCl, 0 °C; e) CH3CO(Cl)R/CH3COONa, EtOH, 0 °C; f) PPh3/
Et3N/CH3CN, 10 min. r.t.
2.0 equiv.) and Et3N (0.17 mL, 1.0 mmol, 2.0 equiv.), and the
reaction mixture was stirred at room temperature for 12 h. Af-
ter completion of the reaction (TLC control), the precipitate
was filtered off, and the filtrate was washed with water, dried,
and crystallized from acetonitrile to give 5a-h.
pyrazole), 6.81-7.21 (m, 5H Ar-H); MS (EI) m/z (rel. inten-
sity) 282 (5, M+), 267 (15), 238 (10), 190 (20), 77 (90), 51
(50). Anal. Calcd. for C15H14N4O2 (282.29) C, 63.81; H, 4.99;
N, 19.84. Found C, 63.73; H, 4.81; N, 19.65%.
3-Acetyl-4,7-diphenylpyrazolo[5,1-c][1,2,4]triazine 5c
Yield 88%; pale yellow solid; mp 235 °C; IR (KBr)
3160, 1680, 1620, 1610, cm-1; 1H NMR (DMSO-d6) d 3.1 (s,
3H, COCH3), 6.3 (s, 1H, pyrazole), 7.0-7.40 (m, 10H, Ar-H);
13C NMR (DMSO-d6, 50 MHz) d 169.1 (CO), 134.1 (C-3),
130.2 (C-4), 134.9 (C-7), 128.4 (C-8), 134.2 (C-9), 127.7,
119.8, 134.6, 130.1, 128.8, 129.9, 127.8, 131.0 (aromatic car-
bons), 14.2 (CH3); MS (EI) m/z (rel. intensity) 314 (38, M+),
237 (62), 194 (12), 117 (15), 77 (20), 52 (30). Anal. Calcd. for
C19H14N4O (314.33) C, 72.59; H, 4.48; N, 17.82. Found C,
72.48; H, 4.41; N, 17.60%.
Ethyl 4,7-diphenylpyrazolo[5,1-c][1,2,4]triazine-3-carbox-
ylate 5a
Yield 86%; yellow crystals; mp 290 °C; IR (KBr) 1725,
1650, 1610, 1585 cm-1; 1H NMR (DMSO-d6) d 1.43 (s, 3H,
CH3), 3.91 (q, 2H, CH2), 6.30 (s, 1H, pyrazole), 6.92-7.31 (m,
10H, Ar-H); 13C NMR (DMSO-d6, 50 MHz) d 168.1 (CO2Et),
131.5 (C-3), 129.1 (C-4), 134.9 (C-7), 128.4 (C-8), 134.0 (C-9),
113.8, 125.6, 128.3, 130.0, 130.2, 128.2, 134.1, 131.6 (aro-
matic carbons), 62.3 (OCH2), 14.7 (CH3); MS (EI) m/z (rel.
intensity) 344 (3, M+), 288 (7), 261 (3), 221 (3), 183 (10), 128
(20), 101 (27), 77 (10). 51 (69). Anal. Calcd. for C20H16N4O2
(344.36) C, 69.75; H, 4.68; N, 16.27. Found C, 69.59; H,
4.49; N, 16.27%.
3-Acetyl-4-methyl-7-phenylpyrazolo[5,1-c][1,2,4]triazine
5d
Yield 85%; white solid; mp 225 °C; IR (KBr) 2920,
1
Ethyl 4-methyl-7-phenylpyrazolo[5,1-c][1,2,4]triazine-3-
carboxylate 5b*
1680, 1635, 1610 cm-1; H NMR (DMSO-d6) d 2.3 (s, 3H,
CH3), 3.1 (s, 3H, COCH3), 6.22 (s, 1H, pyrazole), 6.9-7.20
(m, 5H, Ar-H); MS (EI) m/z (rel. intensity) 252 (15, M+), 237
(17), 194 (20), 117 (30), 77 (20), 51 (40). Anal. Calcd. for
C14H12N4O (252.27) C, 66.65; H, 4.79; N, 22.21. Found C,
Yield 75%; pale yellow solid; mp 185 °C; IR (KBr)
2957, 1715, 1630, 1615 cm-1; 1H NMR (DMSO-d6) d 1.4 (s,
3H, CH3), 2.7 (s, 3H, CH3), 4.22 (q, 2H, CH2), 6.21 (s, 1H,
* Compound 5b have been previously prepared through otherwise different proceedure1 0,11

1192 J. Chin. Chem. Soc., Vol. 50, No. 6, 2003
Barsy
66.60; H, 4.65; N, 22.00%.
mL of dry toluene was added dropwise to a stirred solution of
azophosphoranes 3a-d (8.0 mmol) in 20 mL of the same sol-
vent; the resulting solution was stirred at reflux temperature
for 1-5 h. (in some cases the solid separated on heat). After
cooling, the solid product formed, was collected by filtration
and recrystallized from dioxane/H2O.
Ethyl 4-phenyl-1,2,4-triazolo[5,1-c][1,2,4]triazine-3-car-
boxylate 5e
Yield 75%; yellow crystals; mp 230 °C; IR (KBr) 1725,
1630, 1615, cm-1; 1H NMR (DMSO-d6) d 1.29 (t, 3H, CH3),
4.31 (q, 2H, CH2), 7.41-8.62 (m, 6H, Ar-H and H-3 triazole
protons), 13C NMR (DMSO-d6, 50 MHz) d 168.3 (CO2Et),
142.3 (C-3), 135.6 (C-4), 134.9 (C-7), 134.0 (C-9), 128.6,
129.1, 130.2, 141.7 (aromatic carbons), 59.9 (OCH2), 14.4
(CH3); MS (EI) m/z (rel. intensity) 296 (84, M+), 212 (60),
135 (20), 111 (15), 77 (30), 52 (20). Anal. Calcd. for
C13H11N5O2 (296.26) C, 57.98; H, 4.11; N, 26.01. Found C,
57.89; 4.15; N, 25.90%.
Ethyl 4-(N-phenylamino)-7-phenylpyrazolo[5,1-c][1,2,4]-
triazine-3-carboxylate 7a
Yield 90%; white solid; mp 237 °C; IR (KBr) 1718,
1
1690, 1620, 1580 cm-1; H NMR (DMSO-d6) d 1.2 (t, 3H,
CH3), 3.2 (q, 2H, CH2), 6.11 (s, 1H, pyrazole H-3), 7.3-8.1
(m, 11H, Ar-H and NH protons); MS (EI) m/z (rel. intensity)
360 (84, M++1), 248 (40), 171 (20), 98 (10), 57 (50), 51 (70).
Anal. Calcd. for C20H17N5O2 (359.38) C, 66.83; H, 4.76; N,
19.48. Found C, 66.80; H, 4.75; N, 19.39%.
Ethyl 4-methyl-1,2,4-triazolo[5,1-c][1,2,4]triazine-3-car-
boxylate 5f
Yield 67%; pale yellow solid; mp 185 °C; IR (KBr)
2990, 1715, 1625, 1610 cm-1; 1H NMR (DMSO-d6) d 1.3 (t,
3H, CH3), 2.4 (s, 3H, CH3), 4.40 (q, 2H, CH2), 8.18 (s, 1H,
triazole H-3), 13C NMR (DMSO-d6, 50 MHz) d 169.0 (CO),
142.1 (C-3), 137.5 (C-4), 133.6 (C-7), 133.0 (C-9), 14.2
(COCH3), 20.2 (CH3); MS (EI) m/z (rel. intensity) 207 (15,
M+), 192 (20), 119 (35), 95 (40), 57 (100). Anal. Calcd. for
C8H9N5O2 (207.19) C, 46.37; H, 4.37; N, 33.80. Found C,
46.35; H, 4.31: N, 33.66%.
3-Acetyl-4-(N-phenylamino)-7-phenylpyrazolo[5,1-c]-
[1,2,4]triazine 7b
Yield 87%; pale yellow solid; mp 245 °C; IR (KBr)
3224, 1690, 1620, 1519, cm-1; 1H NMR (DMSO-d6) d 2.3 (s,
3H, COCH3), 6.12 (s, 1H, pyrazole H-3), 7.2-8.1 (m, 11H,
Ar-H and NH protons); MS (EI) m/z (rel. intensity) 330 (93,
M++1), 218 (50), 169 (100), 125 (56), 139 (75), 117 (81), 108
(62), 102 (56). Anal. Calcd. for C19H15N5O (329.35) C, 69.28;
H, 4.59; N, 21.26. Found C, 69.20; H, 4.51; N, 21.16%.
3-Acetyl-4-phenyl-1,2,4-triazolo[5,1-c][1,2,4]triazine 5g
Yield 80%; pale yellow solid; mp 198 °C; IR (KBr)
Ethyl 4-(N-phenylamino)-1,2,4-triazolo[5,1-c][1,2,4]tri-
azine-3-carboxylate 7c
1
1710, 1640, 1625 cm-1; H NMR (DMSO-d6) d 2.8 (s, 3H,
Yield 90%; white solid; mp 280 °C; IR (KBr) 3059,
COCH3), 7.90-8.51 (m, 6H, Ar-H and triazole H-3 protons),
MS (EI) m/z (rel. intensity) 239 (2, M+), 185 (2), 171 (2), 161
(3), 130 (2), 97 (5), 71 (6), 57 (100), 45 (20). Anal. Calcd. for
C12H9N5O (239.23) C, 60.24; H, 3.79; N, 29.27. Found C,
60.20; H, 3.73; N, 29.17%
1
1715, 1640, 1615 cm-1; H NMR (DMSO-d6) d 1.3 (t, 3H,
CH3), 4.21 (q, 2H, CH2), 7.20-7.82 (m, 7H, Ar-H and NH pro-
tons), 8.17 (s, 1H, triazole H-3); MS (EI) m/z (rel. intensity)
285 (16, M++1), 264 (15), 239 (32), 185 (18), 147 (30), 108
(49), 99 (66), 63 (100), 51 (62). Anal. Calcd. for C13H12N6O2
(284.28) C, 54.92; H, 4.25; N, 29.56. Found C, 54.81;H, 4.20;
N, 29.44%.
3-Acetyl-4-methyl-1,2,4-triazolo[5,1-c][1,2,4]triazine 5h
Yield 62%; pale yellow solid; mp 215 °C; IR (KBr)
2999, 1715, 1635, 1610 cm-1; 1H NMR (DMSO-d6) d 2.17 (s,
3H, CH3), 2.80 (s, 3H, COCH3), 8.11 (s, 1H, triazole H-3);
MS (EI) m/z (rel. intensity) 177 (5, M+), 123 (6), 97 (8), 57
(70), 53 (30). Anal. Calcd. for C7H7N5O (177.16) C, 47.45; H,
3.98; N, 39.53. Found C, 47.39; H, 3.97; N, 39.42%.
3-Acetyl-4-(N-phenylamino)-1,2,4-triazolo[5,1-c][1,2,4]-
triazine 7d
Yield 88%; pale yellow solid; mp 228 °C; IR (KBr)
3021, 2952, 1751, 1640, 1625, cm-1; 1H NMR (DMSO-d6) d
2.8 (s, 3H, COCH3), 7.21-7.90 (m, 7H, Ar-H and NH pro-
tons), 8.20 (s, 1H, triazole H-3); MS (EI) m/z (rel. intensity)
255 (93, M++1), 218 (50), 169 (100), 125 (56), 139 (75), 117
(81), 108 (62), 102 (56). Anal. Calcd. for C12H10N6O (254.25)
C, 56.68; H, 3.69; N, 33.15. Found C, 56.61; H, 3.91; N,
33.15%.
General procedure for the preparation of 4-(N-phenyl-
amino)-7-ph-3-substituted pyrazolo[5,1-c][1,2,4]triazines
7a,b and, 4-(N-phenylamino)-3-substituted-1,2,4-triazolo-
[5,1-c][1,2,4]triazines 7c,d
A solution of phenylisocyanate (0.95 g, 8.0 mmol) in 10

Fused Triazines Via a Tandem Wittig/Ring Closure Strategy
J. Chin. Chem. Soc., Vol. 50, No. 6, 2003 1193
General procedure for the preparation of 4-mercapto-7-
phenyl-3-substituted pyrazolo[5,1-c][1,2,4]triazines 9a,b
and, 4-mercapto-3-substituted-1,2,4-triazolo[5,1-c][1,2,4]-
triazines 9c,d
35.79; S, 16.39%.
General procedure for the preparation of pyrazolo[4,5-
c]pyrazoles 13a and 13b
To a solution of azophosphoranes 3a-d (5 mmol) in 25
mL of dry methylene chloride was added excess (7 mL) of
carbon disulfide. The reaction mixture was stirred under ni-
trogen at room temperature for 6 h., the solution was evapo-
rated to dryness, and the residue material was purified by
crystallization from EtOH or EtOH/H2O mixture.
Et3N (9.5 mmol) was added to a stirred mixture of the
appropriate hydrazonyl chlorides 11a and/or 11b (6.0 mmol)
and PPh3 (6.0 mmol), in CH3CN (10 mL) at room tempera-
ture; white crystals formed within a few minutes. The mix-
ture was stirred for a further 1/2 h to complete precipitation;
the yielded product was collected by filtration, washed with a
least amount of CH3CN and crystallized from DMF.
Ethyl 4-mercapto-7-phenylpyrazolo[5,1-c][1,2,4]triazine-
3-carboxylate 9a
4-Oxo-3-methylthiopyrazolo[4,5-c]pyrazol-5-yl(ethoxycar-
bonyl)methylenetriphenylphosphorane 13a
Yield 65%; green solid; mp 185 °C; IR (KBr) 1725,
1
1655, 1622, 1610 cm-1; H NMR (DMSO-d6) d 1.3 (t, 3H,
Yield 95%; white crystals; mp 310 °C; IR (KBr) 1715,
1650, 1635, 1569 cm-1; 1H NMR (DMSO-d6) d 1.32-1.40 (t,
3H, CH3), 2.5 (s, 3H, CH3), 4.24-4.40 (q, 2H,CH2), 6.43-7.95
(m, 15H, Ar-H); MS (EI) m/z (rel. intensity) 514 (100, M+),
468 (60), 391 (25), 269 (60), 262 (80), 237 (40), 77 (20), 51
(50). Anal. Calcd. for C27H23N4O3SP (514.51) C, 63.02; H,
4.50; N, 10.88, S, 6.23. Found C, 63.14; H, 4.51; N, 10.61; S,
6.20%.
CH3), 3.1 (s, 1H, SH), 4.2 (q, 2H, CH2), 6.03 (s, 1H, pyrazole
H-4), 7.21-7.90 (m, 5H, Ar-H); MS (EI) m/z (rel. intensity)
300 (16, M+), 268 (20), 222 (25), 145 (70), 77 (100), 51 (50).
Anal. Calcd. for C14H12N4O2S (300.33) C, 55.98; H, 4.02; N,
18.65; S, 10.67. Found C, 55.93; H, 4.08; N, 18.53; S,
10.61%.
3-Acetyl-4-Mercapto-7-phenylpyrazolo[5,1-c][1,2,4]tri-
azine 9b
4-Oxo-3-methylthiopyrazolo[4,5-c]pyrazol-5-yl(methoxy-
carbonyl)methylenetriphenylphosphorane 13b
Yield 63%; white solid; mp 210 °C; IR (KBr) 3116,
1
1715, 1650, 1612 cm-1; H NMR (DMSO-d6) d 2.8 (s, 3H,
Yield 93%; white crystals; mp 315 °C; IR (KBr) 2290,
1710, 1680, 1620 cm-1; 1H NMR (DMSO-d6) d 2.24 (s, 3H,
CH3), 2.81 (s, 3H, COCH3), 6.43-7.81 (m, 15H, Ar-H); MS
(EI) m/z (rel. intensity) 484 (100, M+), 438 (41), 361 (15), 274
(20), 263 (60), 197 (15), 183 (80), 77 (40), 51 (50). Anal.
Calcd. for C26H21N4O2SP (484.49) C, 64.45; H, 4.36; N,
11.56, S, 6.60. Found C, 64.38; H, 4.32; N, 11.39; S, 6.52%.
COCH3), 2.99 (s, 1H, SH), 6.08 (s, 1H, pyrazole), 7.65-8.22
(m, 5H, Ar-H), MS (EI) m/z (rel. intensity) 270 (3, M+), 222
(5), 194 (10), 117 (20), 77 (90), 53 (40). Anal. Calcd. for
C13H10N4OS (270.30) C, 57.76; H, 3.72; N, 20.72; S, 11.86.
Found C, 57.71; H, 3.70; N, 20.61; S, 11.80%.
Ethyl 4-mercapto-1,2,4-triazolo[5,1-c][1,2,4]triazine-3-car-
boxylate 9c
Yield 70%; pale green solid; mp 230 °C; IR (KBr)
Received July 3, 2002.
1
1725, 1630, 1615 cm-1; H NMR (DMSO-d6) d 1.2 (t, 3H,
CH3), 3.3 (s, 1H, SH), 4.2 (q, 2H, CH2), 8.15 (s, 1H, triazole
H-3); MS (EI) m/z (rel. intensity) 225 (16, M+), 192 (15), 147
(42), 92 (70), 62 (30). Anal. Calcd. for C7H7N5O2S (225.23)
C, 37.32; H, 3.13; N, 31.09; S, 14.23. Found C, 37.30; H,
3.14; N, 31.11; S, 14.02%.
REFERENCES
1. Rao, D. R.; Raychaudhuri, S. P.; Verma, V. S. Int. J. Tropical
Plant Dis. 1994, 12, 177.
2. Elfaham, H. A.; Abdel-Galil, F. M.; Ibraheim, Y. R.; Elnagdi,
M. H. J. Heterocycle. Chem. 1983, 20, 667.
3. Hinshaw, B. C.; Lconoudakis, O.; Townsend, L. B. Ab-
stracts 112d National Meeting of the American Chemical So-
ciety, Washington, D. C. Sept. 1971, No MEDI-15.
4 Ito, I. Japanese Patent 7 030 101 1971; Chem. Abst. 1971,
74, 22827.
3-Acetyl-4-Mercapto-1,2,4-triazolo[5,1-c][1,2,4]triazine 9d
Yield 65%; pale green solid; mp 205 °C; IR (KBr)
1720, 1635, 1620, 1615 cm-1; 1H NMR (DMSO-d6) d 2.6 (s,
3H, COCH3), 3.12 (s, 1H, SH), 8.17 (s, 1H, pyrazole); MS
(EI) m/z (rel. intensity) 195 (5, M+), 162 (15), 147 (30), 119
(50), 61 (25). Anal. Calcd. for C6H5N5OS (195.20) C, 36.91;
H, 2.58; N, 35.88; S, 16.42. Found C, 36.93; H, 2.57; N,
5. Barsy, M. A.; Elrady, E. A.; Hassan, M. E.; Abd El Latif, F.
M. Heterocyclic Communications 2000, 6, 545.

1194 J. Chin. Chem. Soc., Vol. 50, No. 6, 2003
Barsy
6. Raslan, M. A.; Abd-el All, R. M.; Hassan, M. E.; Ahmed, N.
A.; Sadek, K. U. J. Chin. Chem. Soc. 2000, 47, 527.
7. Alemagna, P.; Del Buttero, P.; Licandro, E.; Maiorana, S.;
Trave, R. Tetrahedron 1984, 40, 971.
rahedron 1985, 41, 2503.
10. Elnagdi, M. H.; Elmoghayar, M. R. H.; Fahmy, S. M.;
Ibraheim, M. K. A.; Alnima, H. H. Z. Naturforsch. 1978,
33B(2), 216.
8. Alemagna, P.; Del Buttero, P.; Licandro, E.; Maiorana, S. J.
Chem. Soc., Chem. Comm. 1981, 894.
11. Elnagdi, M. H.; El-Moghayar, M. R. H.; Fleita, D. H.; Hafez,
E. A. A.; Fahmy, S. M. J. Org. Chem. 1976, 41(24), 3781.
9. Alemagna, P.; Del Buttero, P.; Licandro, E.; Papagni, A. Tet-