Synthesis of a few cyclothiadiazanones and aminosulfonyl benzamides from saccharin

Article abstract of DOI:10.1080/17415990903480361

Saccharin is hydrolyzed with two different acids to yield 1,2-di-acid. The di-acid, on chlorination with phosphorous pentachloride, gave 2-chlorosulfonylbenzoyl chloride. The 2-chlorosulfonylbenzoyl chloride on hydrazinolysis gave benzothiadiazinetrione, while with phenyl hydrazine it selectively yielded 2-phenylbenzothiadiazinetrione. 2-chlorosulfonoylbenzoyl chloride with different aromatic 1,2- diamines resulted in dibenzothiadiazocine derivatives. Electron-donating groups in the diamine facilitate while the electron-withdrawing groups retard the cyclization. However, aliphatic diamines, aniline and substituted anilines readily gave acyclic aminosulfonyl carboxybenzamides on condensation with 2- chlorosulfonylbenzoyl chloride. The di-acid and anhydride did not react with either hydrazine/phenyl hydrazine or amines to give the above products. However, when its ester derivative, isopropyl-2- chlorosulfonylbenzoate, condensed with hydrazine, it gave benzothiadiazinetrione. But the ester failed to react with phenyl hydrazine. All the condensation reactions were carried out at room temperature.

Full text of DOI:10.1080/17415990903480361

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Synthesis of a few cyclothiadiazanones
and aminosulfonyl benzamides from
saccharin
P. Venkata Ramana a & A. Ram Reddy a
a Department of Chemistry, University College of Science,
Osmania University, Hyderabad, 500 007, India
Version of record first published: 09 Feb 2010.
To cite this article: P. Venkata Ramana & A. Ram Reddy (2010): Synthesis of a few
cyclothiadiazanones and aminosulfonyl benzamides from saccharin, Journal of Sulfur Chemistry,
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Journal of Sulfur Chemistry
Vol. 31, No. 1, February 2010, 71–81
Synthesis of a few cyclothiadiazanones and aminosulfonyl
benzamides from saccharin
P. Venkata Ramana and A. Ram Reddy*
Department of Chemistry, University College of Science, Osmania University, Hyderabad 500 007, India
(Received 10 August 2009; final version received 1 November 2009)
Saccharin is hydrolyzed with two different acids to yield 1,2-di-acid. The di-acid, on chlorination
with phosphorous pentachloride, gave 2-chlorosulfonylbenzoyl chloride. The 2-chlorosulfonylbenzoyl
chloride on hydrazinolysis gave benzothiadiazinetrione, while with phenyl hydrazine it selectively
yielded 2-phenylbenzothiadiazinetrione. 2-chlorosulfonoylbenzoyl chloride with different aromatic 1,2-
diamines resulted in dibenzothiadiazocine derivatives. Electron-donating groups in the diamine facilitate
while the electron-withdrawing groups retard the cyclization. However, aliphatic diamines, aniline and
substituted anilines readily gave acyclic aminosulfonyl carboxybenzamides on condensation with 2-
chlorosulfonylbenzoyl chloride. The di-acid and anhydride did not react with either hydrazine/phenyl
hydrazine or amines to give the above products. However, when its ester derivative, isopropyl-2-
chlorosulfonylbenzoate, condensed with hydrazine, it gave benzothiadiazinetrione. But the ester failed
to react with phenyl hydrazine. All the condensation reactions were carried out at room temperature.
Keywords: hydrazine; 2-chlorosulfonylbenzoyl chloride; phenylenediamine; benzothiadiazepinone;
dibenzothiadiazocine
1. Introduction
Chemiluminiscence of cyclic hydrazides continue to raise wide interest as they are considered
as effective alternatives to fluorophore and isotopic assays. A considerable body of synthetic
work has been carried out with the object of identifying various factors that control light
production. Two important generalizations are given with respect to the structure–efficiency rela-
tionship. The substituents in a heterocyclic moiety completely inhibit chemiluminiscence, while
the steric factors in a non-heterocyclic ring, i.e. adjacent to carbonyl carbons, C1 and C4, in
luminol, are not favorable to the light-emitting process. However, electron-donating groups in
the non-heterocyclic part with unimpeded resonance enhance the light output. The synthesis of
pyridazine moiety of cyclic hydrazides mostly involved the hydragenolysis of the correspond-
ing anhydrides (1), esters (1b, 2), alkylated imides (1b, 1c, 2d, 2e, 3) and acid chlorides (4).
Lenev et al. (5) reported the synthesis of the chiral cyclic monohydrazide of diphenic acid.
Pawar et al. (6) reported the synthesis of dibenzodiazocinediones by Beckmann rearrangement
*Corresponding author. Email: a_ramreddy@yahoo.com
ISSN 1741-5993 print/ISSN 1741-6000 online
© 2010 Taylor & Francis
DOI: 10.1080/17415990903480361
http://www.informaworld.com

72 P.V. Ramana and A.R. Reddy
of the oximes of dioxomorphanthridines. Mogilaiah et al. (7) reported the synthesis of substi-
tuted phthalazine-1,4-diones by grinding para-toulenesulfonic acid and acid hydrazides in the
solid state. Pyridazine-1,4-diones are important molecules that impart various sizes, shapes and
colors to cucurbits of the Cucurbutaceae family (8). From perusal of the literature, it has been
found that the cyclic hydrazides prepared were mostly di-carbonic acid hydrazides, and there is
no report on the synthesis of thiadiazanones. Therefore, it was considered worthwhile to prepare
a few thiadiazanones, and in this paper, we report the synthesis of a few cyclothiadiazanones and
aminosulfonyl benzamides, starting from saccharin.
2. Results and discussion
The present investigation focuses on the development of a few benzothiadiazanones starting from
saccharin. Saccharin (I) is a readily available stable molecule and is a thio analog of phthalimide.
The latter reaction with hydrazine readily gives phthalizine-1,4-dione, a useful luminescent probe.
A similar reaction is envisaged with saccharin. When saccharin was charged with hydrazine and
refluxed, no hydrazide was obtained. Then it was hydrolyzed with dilute hydrochloric acid to
give 2-sulfobenzoate ammonium salt (II) (9). The product was identified by comparison with
an authentic sample and by its melting point. The structure of the salt II was confirmed by the
disappearance of a saccharin NH signal at δ 12.1 and the appearance of a broad singlet signal at
δ 7.26 for ammonium protons and a δ 14.12 singlet signal for a carboxylic acid proton in 1H NMR.
In the IR spectrum, the new bands obtained at 2805, 2667 and 2536 cm−1 indicate the formation
of salt II. The molecular ion peak at m/z 219 in the electron impact mass spectrum of II indicates
the presence of one nitrogen. Compound II on reaction with hydrazine did not yield the expected
hydrazide. On the other hand, when saccharin was hydrolyzed with dilute H2SO4, it yielded 2-
sulfobenzoic acid (III) (10). The negative mode mass spectrum of III showed a molecular ion
peak at m/z 201. A new peak at 3354 cm−1 in the IR spectrum indicates the formation of an
1
acid. The two acidic protons in III appeared at δ 11.5 in H NMR. The obtained compound II
is in good yield over compound III. Compound III is also a derivative of saccharin, which also
resisted the formation of hydrazide. When II was treated with SOCl2, 2-sulfobenzoic anhydride
(IV) was accessed quantitatively (11). The reaction of II with SOCl2 to IV was proved by the
disappearance of the downfield signal at δ 14.12 of the carboxylic acid proton 1H NMR and with
the appearance of a molecular ion peak at m/z 184 in the mass spectrum. The anhydride IV also
failed to produce hydrazide on reaction with hydrazine. When 25 mmol of either II, III or IV
was mixed with 72 mmol of PCl5, the reaction mixture gave 2-chlorosulfonylbenzoyl chloride (V)
(12) along with a by-product, a gem dichloro compound (2–5%). The by-product was removed
by silica gel column employing petroleum ether/ethyl acetate (9:1) eluent. The formation of V
was confirmed by 1H NMR and mass spectra. The 1H NMR spectrum of V showed three signals
for four aromatic protons. The downfield doublet signal at δ 7.98 was assigned to the aromatic
proton adjacent to the C=O group, the doublet signal at δ 7.78 to that of the proton adjacent to
the SO2 group while the multiplet signal at δ 7.51 to the remaining two aromatic protons. The
mass spectrum of V showed a pseudo-molecular ion [M + H]+ peak at m/z 239. It has been
found that saccharin was not directly transformed to V even under extreme conditions such as
a longer reaction time and high concentration of PCl5. Conversion of I to V involving II as an
intermediate is more efficient than the remaining two paths, i.e. via III and IV. Scheme 1 depicts
the conversion of saccharin to V.
CompoundV on condensation with hydrazines and ortho-phenylenediamines (OPDAs) yielded
cyclic hydrazides, while with amines it gave the corresponding aminosulfonyl carboxy ben-
zamides. When 2 mmol of V was mixed either with 2 mmol of hydrazine hydrate or with
phenyl hydrazine, the reaction mixture gave cyclic six membered benzothiadiazintriones, VIa and

Journal of Sulfur Chemistry 73
O
S
O
CO2H
_
SOCl2
HCl
NH
O
O
S
+
SO3 NH4
O
O
O
II
I
IV
H2SO4
PCl5
PCl5
COCl
SO2Cl
CO2H
SO3H
PCl5
III
V
Scheme 1. Synthesis of 2-chlorosulfonyl benzoylchloride from saccharin.
VIb, respectively. 1H NMR spectrum of 1,2,3,4-tetrahydro-1λ6,2,3-benzothiadiazine-1,1,4-trione
(VIa) exhibited two singlet signals, one at δ 10.11 characteristic of a sulfoxamide proton and the
other at δ 10.65, characteristic of a carboxamide proton, respectively. The four aromatic pro-
tons have given only two signals. The down field multiplet signal at δ 8.05 is assigned to the
aromatic proton adjacent to the carboxamide, while the multiplet signal at δ 7.93 is assigned to
the remaining three aromatic protons. The 13C NMR spectrum of VIa has shown seven signals
for seven carbons. The carbonyl quaternary carbon gave a signal at 161.7 ppm, while the two
aromatic ipso carbons resonated at 138.8 and 126.6 ppm. Similarly, the remaining four aromatic
methine carbons gave signals at 133.9, 133.6, 129.5 and 122.1 ppm, confirming the structure
of VIa. The EI mass spectrum of VIa has shown a molecular ion peak at m/z 198, confirm-
ing its structure. On the other hand, the regioselective cyclo-condensation of V with phenyl
hydrazine is demonstrated by its two different types of acid chlorides. The reactive carboxylic
acidchloride readily condensed with the more electron-dense terminal amino group, while the less
reactive sulfonylchloride condensed less readily with the less reactive aniline nitrogen and gave
2-phenyl-1,2,3,4-tetrahydro-1λ6,2,3-benzothiadiazine-1,1,4-trione (VIb) but not its regioisomer
3-phenyl-1,2,3,4-tetrahydro-1λ6,2,3-benzothiadiazine-1,1,4-trione.The proton NMR spectrum of
VIb showed seven signals at δ 7.26 (m, 2H), 7.69 (m, 2H), 7.87 (t, 2H), 7.97 (m, 1H), 8.07 (t, 1H),
8.47 (t, 1H) and 8.84 (br s, 1H), thus ruling out the possibility of 3-phenyl-1,2,3,4-tetrahydro-
1λ6,2,3-benzothiadiazine-1,1,4-trione. The broad signal at the extreme downfield δ 8.84 is due
to NH of carboxamide, and all the remaining signals are assigned to the aromatic protons. The
ES mass spectrum of VIb showed a molecular ion peak at m/z 274, while that of its pseudo-
molecular ion [M + Na]+ peak at 297 mass units. Similarly, when V reacted with OPDA or
substituted OPDA in 1:1 molar ratio in methanol at room temperature, it yielded dibenzothiadia-
zocinones VIIa–VIIg. Electron-donating groups in OPDA facilitated the formation of VII while
electron-withdrawing groups retarded it. The proton NMR spectrum of 5,6,11,12-tetrahydro-
5,λ6-dibenzo[c,g][1,2,5]thiadiazocine-5,5,12-trione (VIIa) showed six signals at δ 7.52 (s, 2H),
7.69 (m, 2H), 7.84 (s, 2H), 7.94 (d, 1H), 8.03 (d, 1H) and 14.62 (br. s, 2H). 2,3-Diamino-9,10-
acridindione did not give its respective derivative of VII even under drastic conditions such as
high temperature and in the presence of an acid catalyst.
Compound V on treatment with urea and thiourea gave 2,3,4,5-tetrahydro-1H-1λ6,2,4-
benzothiadiazepine-1,1,3,5-tetraone (VIIIa) and 3-thioxo-2,3,4,5-tetrahydro-1H-1λ6,2,4-
benzothiadiazepine-1,1,5-trione (VIIIb), respectively. Interestingly, when 2 mmol of V was
treated with 1–4 mmol equivalents of aniline/substituted anilines or aliphatic diamines, no
cyclic imides are obtained, even at higher temperatures; instead, acyclic aminosulfonyl

74 P.V. Ramana and A.R. Reddy
carboxybenzamides IXa–IXf were obtained. Similar results were reported by Blernat and
Bochenska (12b). The reason for V not forming cyclic imides on reaction with simple primary
amines may be that the initially formed carboxamide nitrogen becomes the less reactive amide
nitrogen, which is incapable of undergoing second nucleophillic substitution at the less reactive
sulphonyl chloride to give a cyclic product. On the other hand, more reactive primary amine
nitrogen can add at the less reactive sulphonyl sulphur. This is further supported by the greater
reactivity of aliphatic amines than aromatic amines. It has been always noticed that formation of
IX occurs immediately after mixing with aliphatic amines, while the aromatic amines take time
to give the corresponding IX.
Ethylenediamine resembles OPDA. On reaction with 2-chlorosulfonyl benzoylchloride, it is
expected to give a product akin to that of OPDA even more readily, since it has reactive aliphatic
amino groups. Interestingly, it did not give the expected cyclothiadiazocine derivative. Similarly,
1,3-propylenediamine did not give its respective cyclothiadiazonine derivative. This may be due
to the steric effect of the initially formed carboxamide. The free amino group at the end of the
initially formed carboxamide has moved away from the proximity of the SO2Cl group at the
ortho position preventing the intra-molecular cyclization. This led to the formation of compounds
IXa and IXb by consuming one more ethylenediamine/propylenediamine molecule, respectively.
However, OPDA possessing a less reactive aniline group undergoes intra-molecular cyclization
due to the rigid geometry of the initially formed carboxamide in which the ortho amino group
comes closer to the SO2Cl. Similar results are obtained with the less reactive urea and thiourea
due to the rigid geometry of the initially formed carboxamide, as found in OPDA.
However, saccharin did not give V directly on reaction with PCl5. The synthesis of compounds
VI–IX starting from V is shown in Scheme 2, and the results are summarized in Table 1.
O
O
NH
NR
NHR
NHR
S
S
O
O
O
O
COCl
VI
IX
R = H, Ph
X
H2N
H2N
R
SO2Cl
NH2
V
H2N
O
S
O
NH
NH
X
NH
O
S NH
R
O
O
O
VIII
VII
X = O, S
Scheme 2. Synthesis of benzothiadiazinone, dibenzothiadiazocinone, aminosulfonyl benza-
mide, benzothiadiazapinone and their derivatives from 2-chlorosulfonyl benzoylchloride.
Compound IV is an anhydride but did not react with hydrazine and phenyl hydrazine even at
reflux temperature. However, on treatment with 2-propanol, it formed 2-chlorosulfonylbenzoic
acid isopropyl ester (X) as shown in Scheme 3. Subsequently, this ester further reacted with
hydrazine (13) and gaveVIa. But attempted condensation of X in place of V with phenyl hydrazine
and other amines under various conditions was not successful.
Compound V is unstable at room temperature. It readily hydrolyzes to di-acid even in
the presence of traces of water in K2CO3. But it is stable at <10 ◦C in a sealed tube.

Journal of Sulfur Chemistry 75
Table 1. List of compounds obtained by the reaction of 2-chlorosulfonyl benzoylchloride with various
hydrzines/amines.
Entry
Reagent
Product
Yielda (%)
M.p. (◦C)
Reaction time (min)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Hydrazine hydrate
Phenyl hydrazine
OPDA
VIa
VIb
42
20
82
65
73
78
82
89
74
88
90
80
92
81
78
77
53
211–214
190–193
>300
>300
291–294
90–93
200–202
>300
>300
>300
>300
177–179
265–269
110–112
119–121
184–186b
250–255
15
65
110
132
95
VIIa
VIIb
VIIc
VIId
VIIe
VIIf
VIIg
IXa
IXb
IXc
IXd
IXe
4-Methyl-OPDA
4, 5-Dimethyl OPDA
4-Chloro-OPDA
4-Nitro-OPDA
Phenylmethanone OPDA
Naphthalene-2,3-diamine
Ethylene diamine
1,3-Propylenediamine
Aniline
76
102
140
125
7
5
75
90
67
110
72
98
p-Amino phenol
p-Chloro aniline
p-Anisidine
IXf
VIIIa
VIIIb
Urea
Thiourea
Notes: aIsolated yield. bBoiling point.
O
NH
NH
S
O
O
O
O
Cl
i-PrOH
O
VIa
S Cl
S Cl
O O
O
O
O
S
V
X
NH
N
Ph
O
O
VIb
Scheme 3. Synthesis of 1,2,3,4-tetrahydro-1λ6,2,3-benzothiadiazine-1,1,4-trione (VIa) from
2-chlorosulfonylbenzoic acid isopropylester (X).
Entries 4 and 6–8 in Table 1 reveal the regioselective cyclization of substituted OPDA.
Substituted OPDAs gave selectively only one of the two possible regioisomers. Conden-
sation of 4-methyl OPDA, 4-chloro OPDA, 4-nitro OPDA and phenylmethanone OPDA
with V resulted in 9-methyl-5,6,11,12-tetrahydro-5λ6-dibenzo[c,g][1,2,5]thiadiazocine-5,5,12-
trione (VIIb), 9-chloro-5,6,11,12-tetrahydro-5λ6-dibenzo[c,g][1,2,5]thiadiazocine-5,5,12-trione
(VIId), 9-nitro-5,6,11,12-tetrahydro-5λ6-dibenzo[c,g][1,2,5] thiadiazocine-5,5,12-trione (VIIe)
and 9-benzoyl-5,6,11,12-tetrahydro-5λ6-dibenzo[c,g] [1,2,5] thiadiazocine-5,5,12-trione (VIIf),
respectively. There is a possibility of obtaining the other regioisomers, i.e. 8-methyl-5,6,11,12-
tetrahydro-5λ6-dibenzo[c,g][1,2,5]thiadiazocine-5,5,12-trione, 8-chloro-5,6,11,12-tetrahydro
-5λ6-dibenzo[c,g] [1,2,5]thiadiazocine-5,5,12-trione, 8-nitro-5,6,11,12-tetrahydro-5λ6-dibenzo
[c,g][1,2,5]thiadiazocine-5,5,12-trione and 8-benzoyl-5,6,11,12-tetrahydro-5λ6-dibenzo[c,g]
[1,2,5] thiadiazocine-5,5,12-trione, respectively, under the given experimental conditions; how-
ever, these regioisomers were not obtained. The reason for not obtaining the above C-8-substituted
regioisomers is not immediately known. All the compounds except the diazepinone formed from

76 P.V. Ramana and A.R. Reddy
urea were solids, and their melting points are higher than that of the respective starting material.
Compounds VIb, VIIIa, VIIIb, IXa and IXb are hygroscopic.
3. Conclusion
In summary, an effective method for the synthesis of benzothiadiazinones, dibenzothia-
diazocinones, aminosulfonyl benzamides and benzothiadiazapinones from 2-chlorosulfonyl
benzoylchloride is described. 2-Sulfobenzoic anhydride and saccharin are structural analogs of
phthalic anhydride and phthalimides, respectively. 2-Sulfobenzoic anhydride and saccharin are not
directly converted to cyclic hydrazides following the Ing–Manske method (14). However, when
saccharin converted to either 2-sulfonyl bonzoylchloride or 2-chlorosulfonylbenzoic acid ester,
these derivatives undergo hydrazenolysis to give 1,2,3,4-tetrahydro-1λ6,2,3-benzothiadiazine-
1,1,4-trione. Structurally dissimilar acid chlorides impart regioselective cyclization.
4. Experimental
The reagents and solvents were of analytical grade and were used without further purification
unless otherwise mentioned. Thin layer chromatography (TLC) was carried out on aluminum
sheets coated with silica gel 60 F254 (Merck). TLC plates were inspected under UV light or
developed by charring after spraying with 5% H2SO4 in ethanol. Micro-analytical data were
obtained by employing a Perkin-Elmer 240c analyzer. IR spectra (KBr pellets) were recorded
1
with a Perkin-Elmer-1700 spectrophotometer. H NMR and 13C NMR spectra were measured
on a Varian INOVA-500 spectrometer. The following abbreviations have been used to explain
the observed multiplicities: s, singlet; d, doublet; t, triplet; m, multiplet; br. s, broad singlet.
Coupling constants have been assigned and listed without duplication in the 1H NMR description
of the synthesized compounds. GCMS was recorded on aVarian 300-MS and electron spray-mass
spectra were recorded on an LCQ system (Finngan MAT, USA) using methanol as the mobile
phase. Melting points were recorded on a Polmon MP 96.
4.1. Synthesis of 2-sulfobenzoate ammonium salt (II)
Saccharin (5 g, 27 mmol) was heated with 20 ml of 10% HCl for 6 h at 95 ◦C. In the beginning the
reaction mixture was turbid and in the due course of time it slowly converted to a clear solution.
After the reaction was completed the solvent water was removed under reduced pressure and
a white solid separated out. The solid was washed with chilled water and dried. Yield 5.26 g
(88%); m.p.: 264–266 ◦C; 1H NMR (300 MHz, DMSO-d6): δ 7.26 (m, 4H), 7.52 (m, 2H), 7.73 (d,
J = 8.0 Hz, 1H), 7.84 (d, J = 7.8 Hz, 1H) 14.12 (s, 1H); IR (KBr): υ 3136, 3025, 2805, 2667,
2536, 1724, 1593, 1397, 1281, 1239, 1191, 1142, 1136, 1080 cm−1; mass (EI): m/z 219 [M]+.
4.2. Synthesis of 2-sulfobezoic acid (III)
Saccharin (7 g, 38 mmol) was suspended in 20 ml of 33% H2SO4 and heated at 90 ◦C for 2 h.After
the reaction was complete, 80% of the water was removed under reduced pressure. The residue
was washed with 20 ml of ice cold water. Yield 6.5 g (85%); m.p.: 68–69 C; 1H NMR (300 MHz,
DMSO-d6): δ 7.56 (m, 4H), 11.52 (s, 2H); IR (KBr): υ 3354 (br. s), 2924, 2845, 1705, 1585,
1445, 1232, 1184, 1112 1063 cm−1; mass (ES): m/z 201 [M–H]−.

Journal of Sulfur Chemistry 77
4.3. Synthesis of 2-sulfobenzoic anhydride (IV)
To a solution of II (5.08 g, 22 mmol) in 10 ml of toluene was slowly added 3.3 ml of SOCl2
(45 mmol) (drop wise) during 30 min at room temperature. The reaction was refluxed for 6 h.
After completion of the reaction, the solvent was removed under reduced pressure to yield a white
solid. The solid was washed with water and dried over anhydrous CaCl2. Yield 2.63 g (65%);
1
m.p.:128–29 C; H NMR (300 MHz, DMSO-d6): δ 7.56 (s, 2H), 7.69 (s, 1H), 7.82 (s, 1H); IR
(KBr): υ 3099, 2954, 1842, 1821, 1721, 1692, 1460, 1373, 1200 cm−1; Mass (EI): m/z 184 [M]+.
13C NMR (75 MHz, DMSO-d6): δ 123.8, 125.3, 128.1, 136.6, 138.4, 140.4, 155.5.
4.4. Synthesis of 2-sulfonyl benzoylchloride (V)
2-Sulfobenzoic acid (5.05 g, 25 mmol), 2-sulfobenzoic anhydride (4.6 g, 25 mmol) or 2-
sulfobenzoate ammonium salt (5.48 g) was heated with PCl5 (15 g, 72 mmol) at 60 ◦C for 2 h.
After the reaction was complete, it was quenched with ice water, extracted with 30 ml of CHCl3
and dried over anhydrous CaCl2. The solvent was concentrated under reduced pressure to yield
2-chlorosulfonyl benzoylchloride. It is purified by column chromatography using petroleum
ether/ethyl acetate (9:1) as an eluent.Yield 68–74%; mp: 37–39 ◦C; 1H NMR (300 MHz, CDCl3):
δ 7.51 (m, 2H), 7.78 (d, J = 7.1 Hz, 1H), 7.98 (d, J = 8.0 Hz, 1H); IR (CHCl3): υ 3099, 3024,
2955, 1792, 1739, 1570, 1435, 1379, 1298, 1184 cm−1; mass (EI): m/z 239 [M]+. 13C NMR
(75 MHz, DMSO-d6): δ 129.5, 133.2, 135.4, 136.8, 140.0, 161.7.
4.5. Reaction of V with hydrazine, phenyl hydrazine, urea, thiourea, aliphatic diamines,
aniline and substituted anilines (VI, VIII and IX)
To a solution of V (478 mg, 2 mmol) in methanol l5 ml of each corresponding reactant (2–4 mmol)
was added at room temperature and the reaction was stirred at room temperature for the appropriate
time (shown in Table 1). When the reaction was complete, the excess solvent was removed under
reduced pressure and the product was purified by column chromatography (2–26% methanol in
chloroform).
4.6. Reaction of V with OPDA and substituted OPDA (VII)
To a stirred solution of V (478 mg, 2 mmol) in 5 ml of methanol was added OPDA/substituted
OPDA (2 mmol) and the reaction mixture was stirred at room temperature for the appropriate
time (shown in Table 1). The excess solvent was removed under reduced pressure. The residue
was taken in 5 ml of acetone, stirred for 30 min and filtered and washed with acetone to get
dibenzothiadiazocinones.
4.7. Spectral data of synthesized compounds
4.7.1. 1,2,3,4-Tetrahydro-1λ6,2,3-benzothiadiazine-1,1,4-trione (VIa)
1H NMR (300 MHz, DMSO-d6): δ 7.88 (s, 3H), 8.05 (s, 1H), 10.11 (s, 1H), 10.65 (s, 1H). IR
(KBr): υ 3366, 3231, 3126, 2891, 1663, 1570, 1424, 1373, 1344, 1188 cm−1. Mass (EI): m/z
198 [M]+. 13C NMR (75 MHz, DMSO-d6): δ 122.1, 126.6, 129.5, 133.6, 133.9, 138.8, 161.7.
Anal. Calcd for C7H6N2O3S: C, 42.42; H, 3.05; S, 16.18; N, 14.14%. Found: C, 42.39; H, 3.02;
S, 16.09; N, 14.22%.

78 P.V. Ramana and A.R. Reddy
4.7.2. 2-Phenyl-1,2,3,4-tetrahydro-1λ6,2,3-benzothiadiazine-1,1,4-trione (VIb)
1H NMR (300 MHz, DMSO-d6): δ 7.26 (m, 2H), 7.69 (m, 2H), 7.87 (t, J = 7.3 Hz, 2H), 7.97 (m,
1H), 8.07 (t, J = 7.1 Hz, 1H), 8.47 (t, J = 7.5 Hz, 1H), 8.84 (br. s, 1H). IR (KBr): υ 3448, 2955,
1716, 1640, 1594, 1299, 1238, 1160, 1081 cm−1. Mass (ES): m/z 275 [M]+, 297 [M + Na]+.
Anal. Calcd for C13H10N2O3S: C, 56.92; H, 3.67; N, 10.21; S, 11.69%. Found: C, 57.03; H, 3.49;
N, 10.15; S, 11.76%.
4.7.3. 5,6,11,12-Tetrahydro-5λ6-dibenzo[c,g][1,2,5]thiadiazocine-5,5,12-trione (VIIa)
1H NMR (400 MHz, DMSO-d6): δ 7.52 (s, 2H), 7.69, (m, 2H), 7.84 (s, 2H), 7.94 (d, J =8.1 Hz,
2H), 8.03 (d, J = 7.9 Hz, 1H), 14.62 (br. s, 2H). IR (KBr): υ 3426, 3061, 2931, 1626, 1564, 1454,
1234, 1177, 1082 cm−1. Mass: 275 [M + H]+, 297 [M + Na]+. 13C NMR (75 MHz, DMSO-
d6): δ 113.5, 124.1, 125.8, 126.2, 128.4, 129.9, 130.1, 130.6, 142.8, 163.8. Anal. Calcd for
C13H10N2O3S: C, 56.92; H, 3.67; N, 10.21; S, 11.69%. Found: C, 56.79; H, 3.66; N, 10.19;
S, 11.71%.
4.7.4. 9-Methyl-5,6,11,12-tetrahydro-5λ6-dibenzo[c,g][1,2,5]thiadiazocine-5,5,12-trione
(VIIb)
1H NMR (300 MHz, DMSO-d6): δ 2.27 (s, 3H), 7.03 (s, 1H), 7.20 (m, 2H), 7.54 (m, 3H), 7.86
(m, 1H), 10.41 (s, 2H). IR (KBr): υ 3223, 2933, 2652, 1718, 1657, 1505, 1334, 1208, 1083 cm−1
.
Mass (ES): m/z 327 [M + K]+. Anal. Calcd for C14H12N2O3S: C, 58.32; H, 4.20; N, 9.72; S,
11.12%. Found: C, 57.98; H, 4.23; N, 9.66; S, 11.28%.
4.7.5. 8,9-Dimethyl-5,6,11,12-tetrahydro-5λ6-dibenzo[c,g][1,2,5]thiadiazocine-5,5,12-trione
(VIIc)
1H NMR (400 MHz, DMSO-d6): δ 2.38 (s, 3H), 3.70 (s, 3H), 7.24 (d, J = 7.8 Hz, 1H), 7.38 (m,
3H), 7.51 (s, 1H), 7.71 (d, J = 8.1 Hz, 1H), 14.32 (br. s, 2H). IR (KBr): υ 3444, 2948, 2922, 1733,
1654, 1440 1320, 1291, 1256, 1174 cm−1. Mass (ES): m/z 341 [M + K]+. 13C NMR (75 MHz,
DMSO-d6): δ 12.1, 19.7, 113.2, 126.6, 127.4, 128.5, 129.2, 131.4, 134.7, 144.3, 150.0, 169.4.
Anal. Calcd for C15H14N2O3S: C, 59.59; H, 4.67; N, 9.27; S, 10.61%. Found: C, 59.62; H, 4.41;
N, 9.19; S, 10.53%.
4.7.6. 9-Chloro-5,6,11,12-tetrahydro-5λ6-dibenzo[c,g][1,2,5]thiadiazocine-5,5,12-trione
(VIId)
1H NMR (400 MHz, DMSO-d6): δ 7.23 (d, J = 7.2 Hz, 2H), 7.31, (s, 1H), 7.61 (d, J = 7.2 Hz,
2H), 7.66 (s, 2H), 8.34 (s, 2H). IR (KBr): υ 3446, 3041, 2927, 1658, 1623, 1566, 1445, 1271,
1163 cm−1. Mass (ES): m/z 309 [M + H]+. Anal. Calcd for C13H9ClN2O3S: C, 50.57; H, 2.94;
N, 9.07; S, 10.39%. Found: C, 50.49; H, 2.91; N, 9.14; S, 10.33%.
4.7.7. 9-Nitro-5,6,11,12-tetrahydro-5λ6-dibenzo[c,g][1,2,5] thiadiazocine-5,5,12-trione
(VIIe)
1H NMR (300 MHz, DMSO-d6): δ 7.79 (s, 2H), 8.14 (d, J = 7.9 Hz, 2H), 8.34 (s, 3H), 13.11
(s, 2H). IR (KBr): υ 3483, 3102, 1787, 1588, 1460, 1407, 1344 cm−1. Mass (ES): m/z 342

Journal of Sulfur Chemistry 79
[M + Na]+. Anal. Calcd for C13H9N3O5S: C, 48.90; H, 2.84; N, 13.16; S, 10.04%. Found: C,
48.82; H, 2.84; N, 13.01; S, 10.11%.
4.7.8. 9-Benzoyl-5,6,11,12-tetrahydro-5λ6-dibenzo[c,g] [1,2,5] thiadiazocine-5,5,12-trione
(VIIf)
1H NMR (400 MHz, DMSO-d6): δ 7.62 (t, J = 7.4 Hz, 2H), 7.73, (m, 3H), 7.80 (d, J = 7.2 Hz,
2H), 7.90 (d, J = 7.2 Hz, 2H); 8.05 (m, 3H), 8.31 (s, 2H). IR (KBr): υ 3048, 2924, 1657, 1622,
1565, 1445, 1325, 1266, 1163 cm−1. Mass (ES): m/z 379 [M + H]+, 401 [M + Na]+.Anal. Calcd
for C20H14N2O4S: C, 63.48; H, 3.73; N, 7.40; S, 8.47 %. Found: C, 63.40; H, 3.78; N, 7.32; S,
8.39 %.
4.7.9. 5,6,13,14-Tetrahydro-5λ6-benzo[g]naphtho[2,3-c][1,2,5] thiadiazocine-5,5,14-trione
(VIIg)
1H NMR (400 MHz, DMSO-d6): δ 7.57 (m, 2H), 7.73 (m, 3H), 7.95 (d, 1H, J = 7.8 Hz), 8.04
(d, J = 7.8, 1H), 8.19 (m, 3H), 8.41 (s, 2H). IR (KBr): υ 3175, 3024, 2914, 2706, 1609, 1497,
1448, 1243, 1178, 1081 cm−1. Mass (ES): m/z 325 [M + H]+. Anal. Calcd for C17H12N2O3S: C,
62.95; H, 3.73; N, 8.64; S, 9.89%. Found: C, 62.78; H, 3.69; N, 8.64; S, 10.07%.
4.7.10. 2,3,4,5-Tetrahydro-1H-1λ6,2,4-benzothiadiazepine-1,1,3,5-tetraone (VIIIa)
1H NMR (300 MHz, CDCl3): δ 7.45 (m, 3H), 7.95 (d, J = 8.3 Hz, 1H), 9.05 (br. s, 2H). IR
(CHCl3): υ 3431, 3023, 2786, 2457, 1727, 1640, 1468, 1299, 1194 cm−1. Mass (ES): m/z 265
[M + K]+.Anal. Calcd for C8H6N2O4S: C, 42.48; H, 2.67; N, 12.38; S, 14.18%. Found: C, 42.12;
H, 2.22; N, 12.52; S, 14.38%.
4.7.11. 3-Thioxo-2,3,4,5-tetrahydro-1H-1λ6,2,4-benzothiadiazepine-1,1,5-trione (VIIIb)
1H NMR (300 MHz, DMSO-d6): δ 7.28 (d, 1H, J = 7.5 Hz), 7.42 (m, 2H), 7.74 (d, J = 7.5, 1H),
8.74 (br. s, 2H). IR (KBr): υ 3433, 3095, 2778, 1713, 1653, 1436, 1303, 1199, 1083, 1021 cm−1
.
Mass (ES): m/z 281 [M + K]+. Anal. Calcd for C8H6N2O3S2: C, 39.66; H, 2.50; N, 11.56; S,
26.47%. Found: C, 39.21; H, 2.27; N, 11.61; S, 26.56%.
4.7.12. N1-(2-aminoethyl)-2-[(2-aminoethyl)amino]sulfonylbenzamide (IXa)
1H NMR (400 MHz, DMSO-d6): δ 2.85 (m, 4H), 3.01 (m, 4H), 3.48 (t, J = 7.6 Hz, 4H), 7.42 (m,
1H), 7.64 (m, 1H), 7.81 (d, J = 7.8 Hz, 1H), 7.91 (d, J = 7.9 Hz, 1H), 8.81(br. s 2H). IR (KBr):
υ 3446, 3224, 2989, 1653, 1636, 1559, 1280, 1164 cm−1. Mass (ES): m/z 287 [M + H]+, 309
[M + Na]+. Anal. Calcd for C11H18N4O3S: C, 46.14; H, 6.34; N, 19.57; S, 11.20%. Found: C,
46.02; H, 6.31; N, 19.57; S, 11.03%.
4.7.13. N1-(3-aminopropyl)-2-[(3-aminopropyl)amino]sulfonylbenzamide (IXb)
1HNMR(300 MHz, DMSO-d6):δ 1.85(m, 4H), 2.86(m, 8H);3.33(br. s, 4H), 7.56(d, J = 7.9 Hz,
1H), 7.69 (m, 1H), 7.86 (d, J = 7.4, 2H), 8.95 (br. s, 2H). IR (KBr): υ 3441, 3076, 2934, 1734,
1643, 1560, 1446, 1323, 1163, 1020 cm−1. Mass (ES): m/z 315 [M + H]+, 337 [M + Na]+.Anal.

80 P.V. Ramana and A.R. Reddy
Calcd for C13H22N4O3S: C,49.66; H, 7.05; N, 17.82; S, 10.20%. Found: C, 49.34; H, 6.88; N,
17.53; S, 10.31%.
4.7.14. N1-phenyl-2-(anilinosulfonyl)benzamide (IXc)
1H NMR (400 MHz, DMSO-d6): δ 7.19 (d, J = 8.1, 7H), 7.39 (m, 7H), 7.72 (s, 2H). IR (KBr):
υ 3456, 2941, 2644, 1716, 1639, 1595, 1304, 1242, 1080, 1014 cm−1. Mass (ES): m/z 353
[M + H]+. 13C NMR (75 MHz, DMSO-d6): δ 122.3, 126.5, 127.1, 127.3, 128.5, 129.1, 129.6,
130.6, 130.8, 131.3, 132.8, 144.7, 169.2. Anal. Calcd for C19H16N2O3S: C, 64.76; H, 4.58; N,
7.95; S, 9.10%. Found: C, 64.39; H, 4.56; N, 7.81; S, 9.22%.
4.7.15. N1-(4-hydroxyphenyl)-2-[(4-hydroxyanilino)sulfonyl]benzamide (IXd)
1H NMR (300 MHz, DMSO-d6): δ 6.03(s, 1H), 6.49 (s, 1H), 6.75 (m, 3H), 6.89 (t, J = 7.8 Hz,
1H), 6.96 (d, J = 7.2 Hz, 1H), 7.09 (s, 1H), 7.12 (d, J = 8.1 Hz, 1H), 7.40 (s, 1H), 7.51 (t,
J = 8.0 Hz, 1H), 7.86 (d, J = 7.7 Hz, 1H), 9.51 (s, 1H), 9.83 (s, 1H), 11.15 (br. s, 2H). IR
(KBr): υ 3457, 3182, 2910, 1642, 1597, 1464, 1280, 1192 cm−1. Mass (ES): 385 [M + H]+, 407
[M + Na]+.Anal. Calcd for C19H16N2O5S: C, 59.37; H, 4.20; N, 7.29; S, 8.34%. Found: C, 59.27;
H, 4.34; N, 7.34; S, 8.28%.
4.7.16. N1-(4-chlorophenyl)-2-[(4-chloroanilino)sulfonyl]benzamide (IXe)
1H NMR (300 MHz, DMSO-d6): δ 7.33 (m, 8H), 7.71 (m, 4H), 7.94 (br. s, 2H). IR (KBr): υ 3433,
2928, 1728, 1657, 1595, 1493, 1238, 1024, 619 cm−1. Mass (ES): m/z 444 [M + Na]+. Anal.
Calcd for C19H14Cl2N2O3S: C, 54.17; H, 3.35; N, 6.65; S, 7.61%. Found: C, 54.11; H, 3.48; N,
6.65; S, 7.73%.
4.7.17. N1-(4-methoxyphenyl)-2-[(4-methoxyanilino)sulfonyl] benzamide (IXf)
1H NMR (300 MHz, CDCl3): δ 3.56 (s, 6H), 6.53 (s, 4H), 7.14 (m, 8H), 7.83 (br. s, 2H). IR
(KBr): υ 3443, 2924, 2843, 1633, 1510, 1452, 1383, 1249, 1170, 1020 cm−1. Mass (ES): m/z
413 [M + H]+, 435 [M + Na]+. Anal. Calcd for C21H20N2O5S: C, 61.15; H, 4.89; N, 6.79; S,
7.77%. Found: C, 61.02; H, 4.67; N, 7.01; S, 7.91%.
Acknowledgements
One of the authors (PVR) is thankful to the Head, Department of Chemistry, Osmania University, Hyderabad and the
Director, IICT, Hyderabad, for providing the facilities.
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