Carbon disulfide in heterocyclic organic synthesis; synthesis of polyfunctionally substituted sulfur and nitrogen heteroaromatics

Article abstract of DOI:10.1080/10426500701407722

Reaction of cayno acetamdie with carbon disulphide in alkaline medium, e.g., potassium hydroxide, or potassium ter butoxide gave the gem-dithiol (1). While in presence of ammonium hydroxide the ammonium salt (2) was obtained. Reactions of (1) or (2) with

Full text of DOI:10.1080/10426500701407722

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Carbon Disulfide in
Heterocyclic Organic Synthesis;
Synthesis of Polyfunctionally
Substituted Sulfur and Nitrogen
Heteroaromatics
Salem E. Zayed a
a Chemistry Department, Faculty of Science, South
Valley University, Qena, Egypt
Published online: 16 Jul 2007.
To cite this article: Salem E. Zayed (2007): Carbon Disulfide in Heterocyclic
Organic Synthesis; Synthesis of Polyfunctionally Substituted Sulfur and Nitrogen
Heteroaromatics, Phosphorus, Sulfur, and Silicon and the Related Elements, 182:9,
2193-2204
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Phosphorus, Sulfur, and Silicon, 182:2193–2204, 2007
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500701407722
Carbon Disulfide in Heterocyclic Organic Synthesis;
Synthesis of Polyfunctionally Substituted Sulfur and
Nitrogen Heteroaromatics
Salem E. Zayed
Chemistry Department, Faculty of Science, South Valley University,
Qena, Egypt
Reaction of cayno acetamdie with carbon disulphide in alkaline medium, e.g., potas-
sium hydroxide, or potassium ter.butoxide gave the gem-dithiol (1). While in pres-
ence of ammonium hydroxide the ammonium salt (2) was obtained. Reactions of
(1) or (2) with different reagents in different mediums gave pyridine, pyrimidines,
thiophene, and thiopyranones derivatives.
Keywords Carbon disulphide; keten thioacetals; sulfur chemistry; thioacetals
RESULTS AND DISCUSSION
Ketene gem-dithols have proved useful starting materials for a vari-
ety of heterocyclic and homocyclic aromatic compounds.1–5 Some of its
derivatives were found to possess wide applications. It have an antihep-
atotoxic in preventive curative and curative tests as shown by measur-
ing serum glutamate-oxalacetate transaminase due to radical trapping
formation of the thiol group.6 Also, some derivatives were found to pos-
sess activities as herbicidal agents against field and aquatic weeds as
well as mullscicides.7 Moreover, the reactivity are extended to include
nematocide,7 baceriocide,7 gungicide,7 and antidates against ionizing
radiations.7–9
An extensive work has been reported on the synthesis of some
heteroaromatics. Although ketene gem- dithioacetals has been exten-
sively utilized in organic synthesis, little have been reported on the
utility of this versatile reagents (1) or (2) for building up a series of
new compounds.
In continuation to our work on the behavior of ketene gem-
dithiols,10–12 the precursor (1) could be obtained on reacting cayno
Received December 21, 2006; accepted April 2, 2007.
Address correspondence to Salem Zayed, South Valley University, Faculty of Science,
Chemistry Department, Qena, Egypt. E-mail: zayedse@yahoo.com
2193

2194
S. E. Zayed
SCHEME 1
acetamide with carbon disulphide in a base (e.g., NaOH, KOH,
KO.terBu) in aqueous medium. Using ammonium hydroxide in place
of the above bases, precursor (2) was prepared (Scheme 1). On boiling
(2) in alkaline aqueous medium, the precursor (1) was isolated.
Reactions of (2) with some other reagents e.g., ω-bromo—acetophenone
(3), benzoyl acetonitrile (4), and/or with phenylacetyl chloride (5) in
boiling dioxane in the presence of triethylamine as a catalyst ,the
poly functionally substituted thiophene (6), nicotinamide (9), and
thiopyranone (10) derivatives (Scheme 2)
SCHEME 2

Carbon Disulfide in Heterocyclic Organic Synthesis
2195
Formation of (9) is presumably proceeded via intermediates (7 and
8), followed by Dimorth rearrangement. Structure assignment of the
products (6, 9, and 10) was supported by analytical and spectral mea-
surements.
Disappearance of a peak for cayno group and appearance of a peak
for amino group confirmed the structures (6 and 9). H1nmr revealed
signals that proved presence of the phenyl, sulfohydyl and amidic amino
protons, in addition to a broad signal for amino groups.
Furthermore, on boiling (5) with (2) gave the thiopyranone deriva-
tive (10). Moreover, behavior of (2) towards dicyano diamide, in boiling
ethanol in the presence of a catalytic amount of triethylamine was stud-
ied and gave the polyfunctionlly substituted pyrimidine derivative (11).
Treating (11) with benzylidine malono nitrle in boiling ethanol in the
presence of a catalytic amount of triethylamine could form the pyrido-
pyrimidine(14) (Scheme 3).
The reaction pathway was assumed to proceed through Michael ad-
dition as a first step followed by nucleophilic addition to form the inter-
mediates (12 and 13), respectively.
Spectral and analytical measurements gave a satesfy data to confirm
structures of (11) and (14). Reaction of (2) with phenyl hydazine in
boiling ethanol in the presence of a catalytic amount of triethylamine
was also reported to give the pyrazolone derivative (15). Substrate (2)
when reacted with triethyl orthformate in boiling ethanol, the cyclic
dithiol derivative (16) was produced. Meanwhile, the reaction of (2) with
SCHEME 3

2196
S. E. Zayed
SCHEME 4
azmethane derivative (18) in boiling dioxane and a catalytic ammount
of triethylamine, favored formation of the condensed system (20) via
formation of the intermediate (19) (Scheme 4).
The obtained spectral data ruled out any other probabilities for the
reactions of (1) or (2) with phenyl hydrazine or with triethylorthofor-
mate, since the data offer signals that supported structures of (15–20).
The ketene gem-dithiol (1) could also be obtained from the trithione
derivative (21) via reaction of cayno actamide (20) with carbon disulfide
and elemental sulfur, followed by ring opening under the influence of
sodium hydroxide (Scheme 5).
An interesting novel method for the synthesis of substituted pyra-
zolopyrimidine derivative (24) was proceeded via the reaction of the
precursor (22)with carbon disulfide in alkaline medium. On treating
(23) with thiourea in a basic medium, the pyrazolopyrimidine deriva-
tive (24) was isolated (Scheme 6).
Dimerization of (2) resulted in formation of the trithione derivative
(disaurine) (25), which on boiling in ethanol looses a sulfur atom and
finally the cyclic ditheitane (26) derivative was formed (Scheme 7).
Furthermore, reaction of substrate (27) with barbituric acid (28) in
boiling ethanol/sodium ethoxide, resulted in formation of pyrimidine
derivative (30) via formation of the unisolable intermediate (29). The

Carbon Disulfide in Heterocyclic Organic Synthesis
2197
SCHEME 5
reaction is assumed to proceed via condensation of keto group in (27)
with methylene moiety in (28) follweed by water elimination. Mean-
while the reaction of 1,3-cyclohexane dione (31) with (27) in boling
methylne chloride in presence of triethylamine yielded product (33)
(Scheme 8).
Formation of (33) was assumed to proceed via Michael addition
to ethylenic moiety in (27) followed by water elimnation. Then the
second molecule (27) reacted with carbonyl moiety followed by wa-
ter elimnation. Obtained spectral and elemental data supported the
structure (32) and ruled out any other assumed structures. Benzyli-
dene thiosemicarbazide (34) was also subjected to reaction with (27)
SCHEME 6

2198
S. E. Zayed
SCHEME 7
in boiling ethanol/sodium ethoxide and gave the pyrimidine derivative
(36) (Scheme 9).
EXPERIMENTAL
M.Ps are uncorrected and measured by open capillary tubes on a hot
plate surface IR spectrum (K Br) were recorded on Shimadzu part
No: 200-91506 spectrophotometer. H1NMR spectra were recorded on
Varian–Gemini 200-200MHz (DMSO; Mass spectra were measured on
Shimadzu SQ 100 (At Cairo University, analysis unit). H1NMR spectra
(DMSO or CDCl3) were recorded on BRUKER, MCKCYC 53.001AU
PROG: 300-MHz (At the Chemistry Department, University of Man-
itoba, Canada. Elemental analysis values were determined at Cairo
University (Egypt) laboratories.
3,3-Dimercapto 2-cyanmide 2 and 3
1 The gem-dithiol (2) was prepared according to the reported proce-
dure via action of CS2/ K ter. Butoxide in benzene on cayno acetamide
in place of NaOH in water, m.p. 112◦C (reported m.p. 112◦C) yield
89.67%.
2 Gem-dithiol (1) could also be prepared from reaction of CS2 with
cayno-acetamide in presence of NH4OH in cold condition (at room
temperature), m.p. 143◦C (reported 142◦C) yield 88.57%.
3 Heating (2) in aqueous NaOH gave (1) 87.94%.
General Procedure for the Synthesis of 6, 9, and 10
To the reagents, bromoacetophenone (3), benzoyl actonirile (4), and
phenyl-acetylchloride (5) (0.01 mol) was added an equimolar ratio from

Carbon Disulfide in Heterocyclic Organic Synthesis
2199
SCHEME 8
(2) (0.01mol) in dioxane (100 ml) contained a catlytic ammount of
Et3N(2 drops), then the reaction mixtures were heated under reflux
for 3 h. On concentration the solvent to the third of its volume and cool-
ing , the precipitated solid products were gathered and recrystallized
from DMF.
3-Amino 4-Benzoyl 5-Mercapto-Thiophene 2-Carboxylic Acid
Amide (6)
Obtained as a brown crystals, m.p. 132 c◦ m/e 278.02. Analysis for
C12H10N2O2S2 (278.02) yield; 68.51%. Required % C, 51,78, H, 3.62 N,
10.06; S,23.04, Found, C, 51.77 ;H,3.7; N,11.0.
H1NMR δ m, 7.45–7.81 5H; C6H5; s, 6. 8.1; 2H, CONH2; s, 4.66; 2H
NH2; s, 3.22, 1H, SH.
4-Amino 5-Benzoyl 2,6-Dimercapto Nicotinamide 9.
Obtained as a brown crystals.yield; 77.92% ,M.p. 183◦C Analy-
sis for C13H11N3O2S2 (305.38) Requires % C,51.13, H,3.63; N,13.76;
S,21.00. found %, C 51.2; H, 3.7; N, 13.79, S, 20.76. H1 nmr, δ m,

2200
S. E. Zayed
SCHEME 9
7.44–8.11, 5H C6H5, s, 5,57 2H NH2;s,5.86 2H, amidic NH2, s 2.86, 2H
2SH.
4-Amino 2-Mercapto 6-Oxo 6H Thiopyran 3-Carboxylic Acid
Amid 10
Collected as a dark brown powder,yield 78.64%; m.p. 212◦C. Analysis
for C6H6N2O2S2 (202.25) Required % C, 35.63; H, 2.99; N, 13.85; S,
31.71; Found% C, 35.71; H, 3.11; N,14.0;s, 32.22. Hnmr δ s 6.12 1H CH,
s, 5.43 2H, CONH2.
6-Amino 2-Caynoimino 4-Mercapto 1,2-Dihydroppyrimidine
5-Carboxylic Acid Amide 11.
A mixture of (2) (0.01 mol, 1.94 g) and caynamide dimer (01.0,
0.084 mol) in absolute ethanol (75 ml) contained (1ml,Et3N) was heated
under reflux for 2 h. After cooling the precipitated product was filtered
and recrystallized from DMF as a dark red crystals. Yield 82.43%, m.p.
266◦C. Analysis for C6H8N6OS (212.23). Required % C, 33. 96; H, 3.80;
N, 39.60; S, 15.11, Found % C, 34.01; H, 4.00; N,40.00; S, 15.53.; I.R2228
/cm−1 (CN), 1695/cm−1(C=O amide). H1nmr δ; s, 8.57 2H NH2CO s,4.23
2H NH2,s, 3.87 1H SH.
4-Amino 6-Caynoimino 8-Mercapto 2-Phenyl 6H
Pyrimido[1,6-a] Pyrimidine 9-Carboxylic Acid Amide 14
To 11 (0.01 mol, 3.38 gm) in absolute ethanol (100 ml) contained Et3N
(1 ml), benzylidin-malono nitrle (0.01 mol, 1.54 g) was added while heat-
ing under reflux for 4 hours (until evolution of H2S ceased). On cooling,
the separated crop was filtered off and recrystallized from DMF yield

Carbon Disulfide in Heterocyclic Organic Synthesis
2201
76.53%. Analysis for C15H11N7OS (337. 36) yield 68.32%. Calculated %
C, 53.40; H,3.29; N, 29.06; S,9.50 found % C, 53.47; H, 3.32; N,30.00; S,
10.11. IR, 2235 cm−1 (CN), H1NMR, δ ; s, 8.12 2H, CO NH2m,7.1–7.87
5H C6H5; s, 5.98 1H,CH=C s, .4.87 2H NH2; s,1.66 1H SH.
4-Amino 1-Phenyl 5-Mercapto 1-H Pyrazole 3-Carboxylic Acid
Amide 15
To a solution of 2 (0.01 mol; 1.94 g) in absolute ethanol (75 ml) was
added to phenylhydrazine ( 0.013 mol, 1.4 ml) in absolute ethanol (25
ml) in presence of Et3N (1ml). The reaction mixture was then heated
under reflux for 2.5 h, followed by cooling to room temperature. The
separated crop was recrystallized from ethanol to give a pale yellow
crystals of m.p. 129◦C. Analysis for C10H10N4OS (234.28); yield 87.62%.
Required %, C, 51.27; H, 4.30; N, 23.91; S, 13.69, Found % C, 51. 29; H,
4.33; N, 24.00; S, 14.00. I.R/ cm−1, 1692(CONH2); 33450 (NH2).H1 nmr
δ s, .8.12 2H CO NH2; m,7.00–7.73 5H C6H5;s, 5.32 2H NH2; S, 1.76 1H
SH.
2-Cayno 2-(4-Ethoxy-[1,3] Dithietan 2- Ylidene) Acetamide 16
To 2 (0.01 mol, 1.6 g) in ethanol (50 ml) was added triethylorthoformate
(0.01, 1.5 ml) in ethanol (25 ml) drop wise (5 min), while stirring at room
temperature for 30 min .The reaction mixture then, heated under reflux
for 2 h. On cooling, the separated pale brown solid products was filtered
and recrystallized from DMF. Yield 84.33%, m.p. 196◦C. (shrinking).
Analysis for C7H8N2O2S2 (216.28), Required %, C, 38.87; H, 3.73; N,
12.95; S, 29.65. Found %, C, 39.00; H, 3.77; N, 13.00; S, 31.00. I.R/ cm−1
2225, CN; 1700, amidic CONH2. H1nmr δ t,1. 64 3H CH3 (ester), q, 4.23
2H CH2(ester), s, 5.67 1H cyclic CH-, s, 8.12 1H CONH2.
7-Amino 2-(4-Chlorophenyl) 6- Cayno 5- Oxo 5H
[1,3,4]thiadiazole [3,2-a] Pyridine 8-Carboxylic Acid Amide 20
On heating a mixture of 18 (1.93 g; 0.01 mol) and 2 (1.94 g; 0.01 mol) in
dioxane (100 ml) and Et N (ml) under reflux for 3 1/ h followed by cool-
2
3
ing to room temperature; a dark brown precipitation was gathered m.p.
238◦C, yield 67.78%. Analysis for C14H8ClN5O2S (345.76). Required %
C, 48.63; H, 2.33; N, 20.25; S, 9.27.Found % C, 48.65; H, 2.35; N, 21.00;
S, 9.44. IR/cm−1 1755, C = O; 1675, CONH2; 3325, NH2; 2225, CN. H1
nmr δ s, 8.22, 2H NH2; m, 7.1–7.69,4H C6H4, s, 6.82 2H CONH2.

2202
S. E. Zayed
5-Cyano 3-Thioxo 3H (1,2) Dithiole 4-Carboxylic Acid Amide
(21)
A mixture of caynoacetamide (20) (0.01 mol, 0. 84 g), carbon disulfide
(0.013 mol, 1 ml) and elemental sulfur (0.2 mol, 6.4 g) in DMF (50 ml)
and Et3N(1 ml) was stirred at room temperature for 30 min. Heating
the mixture under reflux for 3 h followed by distillation of the excess
DMF, a yellow residue was purified from ethanol, m.p. 205◦C. Analysis
for C5H2N2OS3 (202.28), yield 73.52%. Required % C,29.69; H, 1.00; N,
13.85; S, 47.56; Found % C, 29.72; H, 0.96; N, 13.92; S, 7.66., IR/cm−1
2225; CN, 1725; CONH2.
5-Mercapto 3-Oxo 1-Phenyl 2,3-Dihydro 1H-Pyrazole
4-Carbonitrile 23
To an alcoholic aqueous solution (NaOH, 10 g/50 ml C2H5OH/50 ml
H2O) was added caynoacetic acid N-phenyl hydrazide (22) (0.01 mol;
1.75 g) in portions, followed by adding carbon disulfide ( 0.015 mol;
1.2 ml) while stirring at room temperature. After complete addition,
the reaction mixture was stirred for further 3 h. On neutralization with
concentration sulfuric acid a yellow residue formed is purified from
ethanol to give 23 m.p. 184◦C. Analysis for C10H7N3OS (217.24), yield
92.42%. Required % C, 55.29; H, 3.25; N, 19.34; S, 14.76. Found % C,
55.31; H, 3.25; N, 19.33; S, 14.82. IR/cm−1 2225 CN; 3350 NH. H1nmr
δ s, 8.00, 1H NH; m, 6.89–7.44, C6H5;s,1.55 1H SH.
4-Amino 6-Ethoxy 1-Phenyl
1,2-Dihydro-Pyrazolo[3,4-d]Pyrimidine 3-One 24
A mixture of 23 (0.01 mol; 2.172 g) and thiourea (0.01 mol; 0.76 g) in
absolute ethanol(50 ml) contained sodium ethoxide (0.012 mol, 0.81 g.
NaOC2H5) was heated under reflux for 6 h. On neutralization with
cold conc. hydrochloric acid, a pale yellow product was obtained and
purified from ethanol. m.p. 259◦C. Analysis for C13H13N5O2 (271.10)
yield 59.78%. Requires % C, 57.56; H, 4.83; N, 25.82. Found % C, 57.58;
H, 4.84; N, 25.83. IR/cm−1 3450 NH2; 3330 NH; 1690 CONH.H1nmr δ;
s, 8.12, 1H, NH; m, 6.98–7.44, 5H, C6H5; s, 4.42, 2H, NH2; q, 4.12, 2H,
CH2t, 1.33, 3H, CH3.
2-[5-(Carbamoyl-cayno-methylene) [1,2,4]trithiolan
3-ylidene]2-cayno Acetamide 25
To an slightly alkaline solution (20 ml) (20% NaOH) was added the
ammonium salt 2 (2.0 g) with gentle heating for 15 min (until the

Carbon Disulfide in Heterocyclic Organic Synthesis
2203
evolution of H2S gases ceased). Purification of the formed dark brown
solid product from benzene gave 25. M.p. 289◦C. (shrinking) yield
77.45%. Analysis for C8H4N4O2S3 (284.338). Requires % C, 33.79; H,
‘1.42; N, 19.70; S, 33.83. Found % C, 33.77; H, 1.44, N, 19.68; S, 44.00.
IR/cm−1 2222&2225, 2CN.
2-[4-(carbamoyl-Cayno Methylene) 1,3 dithietan
2-ylidene2-caynoacetamide 26
On boiling (25) in ethanol for 4 h gave a red crystals. Purification
of the product from benzene obtained a brown crystals m.p. 212◦C
yield 65.32%. Analysis for C8H4N4O2S2 (252.273) Required % C, 30.09;
H, 1.60; N, 22.21; S, 25.42. Found % C, 30.00; H, 1.55; N, 22.23; S,
25.55.IR/cm−1 2222&2225, 2CN.
7-Mercapto 5-Thiophene 2-yl Thiopyrano[2,3d] Pyrimidine
2,4-Dione 30
A mixture of equimolar ratio of (27), (30) and sdium ethoxide (0.01 mol)
in ethanol (75 ml) were heated under reflux for 2.5 h. On cooling a
white yellowish solid product was separated. Purification from ethanol
gave a product of m.p. 179◦C. Analysis for C11H7ClN2O2S3 (330.83)
yield 69.91%. Required % C, 39.93; H, 2.13; N, 8.47; S, 29.08. Found%
C, 40.00; H, 2.15; S, 29.11. H1nmr δ; t, 7.37–7.39 3H (thiophene ); d,
7.3–7.99, 1H, NH s, 5.74.1H C5H1.
5-Thiophene 2-yl 2,3,7,8,9,10a Hexahydro 1H 10,11 Dithia
Benzo[b]fluorene 33
To (27) (0.01 mol; 2.02 gm)in CH2Cl2 (50 ml) in presence of Et3N (1
ml) was added cyclohexane dione (0.01 mol; 1.12 g) while stirring at
room temperature. Strring the reaction mnixture with gentle heating
under reflux for 3 h. Leaving over night left a yellow solid product,
m.p. 235◦C yield 81.44%. Analysis for C19H16O2S3 (372.52). Required
%C, 61.26; H, 4.33;S,25.82. Found % C, 61.29;H, 4.37; S, 26.00. H1nmr
δ,t,7.35–7.38 3H,(thiophene), t, 5.56–5.65, 1H C4; m, 3.35–3.82, 12H,
6CH2 (cyclohexane).
1-(4-Chlorobenzylidene) Amino 6-Mercapto 4-Thiophene 2-yl
1-H Pyrimidine 2-Thione 36
A mixture of equimolar ratio from (27) and (34) (0.01 mol) in ethanol
(75 ml) and sodium ethoxide (0.022 mol) were heated under reflux for

2204
S. E. Zayed
3 h. Filtration of the separated solid producer and purification from
ethanol gave (36) m.p. 218◦C yield 79.24%. Analysis for C15H10ClN3S3
(363.91). Required % C,49.51; H,2.77; N,11.55; S,26.43. Found%
C,49.55;H,2.75;S,26.67. H1nmr δ, m,8.31–8.36., s; 8.01 1H CH = N,
m,3H 7.38–7.49, (thiophene); s; 6.44 1H (C5 pyrimidine) s, 1.32 1H, SH.
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