Electrogenerated base-promoted synthesis of dithiocarbamate acid esters and 3-(N-substituted-amino)-2-cyanodithiocrotonates from primary or secondary amines and carbon disulfide

Article abstract of DOI:10.1080/10426500701501607

Electrogenerated cyanomethyl anion promotes the reaction between primary or secondary amines, carbon disulfide, and alkyl or benzyl halide. Secondary amines are converted to alkyl or benzyl dithiocarbamates, whereas primary amines give N-substituted alkyl

Full text of DOI:10.1080/10426500701501607

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Electrogenerated Base-
Promoted Synthesis of
Dithiocarbamate Acid Esters
and 3-(N-Substituted-amino)-2-
cyanodithiocrotonates from
Primary or Secondary Amines
and Carbon Disulfide
Meriem Toumi a , Noureddine Raouafi a , Khaled
Boujlel a , Issa Tapsoba b , Jean-Paul Picard c
Michel Bordeau c
a Laboratoire de Chimie Analytique et
&
Electrochimie, Faculté des Sciences de Tunis ,
Campus Universitaire , Tunis El Manar, Tunisie
b Laboratoire d'Activation Moléculaire et de
Réactivité Electrochimique , Ecole Normale
Supérieure , Paris, France
c Laboratoire de Chimie Organique et
Organométallique , Université Bordeaux , Talence,
France
Published online: 23 Aug 2007.
To cite this article: Meriem Toumi , Noureddine Raouafi , Khaled Boujlel , Issa
Tapsoba , Jean-Paul Picard & Michel Bordeau (2008) Electrogenerated Base-
Promoted Synthesis of Dithiocarbamate Acid Esters and 3-(N-Substituted-amino)-2-
cyanodithiocrotonates from Primary or Secondary Amines and Carbon Disulfide,
Phosphorus, Sulfur, and Silicon and the Related Elements, 182:10, 2477-2490, DOI:
10.1080/10426500701501607

To link to this article: http://dx.doi.org/10.1080/10426500701501607
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Phosphorus, Sulfur, and Silicon, 182:2477–2490, 2007
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500701501607
Electrogenerated Base-Promoted Synthesis of
Dithiocarbamate Acid Esters and
3-(N-Substituted-amino)-2-cyanodithiocrotonates from
Primary or Secondary Amines and Carbon Disulfide
Meriem Toumi
Noureddine Raouafi
Khaled Boujlel
Laboratoire de Chimie Analytique et Electrochimie, Faculte´ des
Sciences de Tunis, Campus Universitaire, Tunis El Manar, Tunisie
Issa Tapsoba
Laboratoire d’Activation Mole´culaire et de Re´activite´ Electrochimique,
Ecole Normale Supe´rieure, Paris, France
Jean-Paul Picard
Michel Bordeau
Laboratoire de Chimie Organique et Organome´tallique, Universite´
Bordeaux, Talence, France
Electrogenerated cyanomethyl anion promotes the reaction between primary or sec-
ondary amines, carbon disulfide, and alkyl or benzyl halide. Secondary amines are
converted to alkyl or benzyl dithiocarbamates, whereas primary amines give N-
substituted alkyl or benzyl 3-amino-2-cyanodithiocrotonates. The mechanisms are
discussed.
Keywords
3-(N-substituted-amino)-2-cyanodithiocrotonates;
carbon
disulfide;
cyanomethyl dithiocarbamates; anion; EGBs
INTRODUCTION
In recent years, several articles have been devoted to the synthesis
of dithiocarbamates because they are widely used as antibacterial,1−4
anthelmintic,5,6 fungicidal,1,2,4,7−10 and algicidal11 reagents.
Received May 6, 2006; accepted May 4, 2007.
The authors thank M. R. S. T (Ministe`re Tunisien pour la Recherche Scientifique et
Technique) Lab CH02 for financial support.
Address correspondence to Khaled Boujlel, Laboratoire de Chimie Analytique et Elec-
trochimie, Faculte des Science de Tunis, Campus Universitaire, El Manar, Tunis 2092,
Tunisia. E-mail: khaled.boujlel@fst.rnu.tn
2477

2478
M. Toumi et al.
More recently, it was found that brassinin12 and related
compounds13,14 possess in vitro and in vivo antitumor activity.
The classical synthesis of N,N-dialkyldithiocarbamates utilizes the
reaction of dithiocarbamic acid salts with alkyl halides,3,15−22 dialkyl
phosphates23 or electron-deficient olefins.24,25
Herein we report the synthesis of dithiocarbamates of the gen-
eral structure1 and of new N-substituted alkyl or benzyl 3-amino-2-
cyanodithiocrotonates 3 through the condensation of the electrogener-
ated cyanomethyl anion at a copper electrode with secondary or primary
amines, respectively, and carbon disulfide.
The first aim of this study was the development of an electrochem-
ically induced synthesis of dithiocarbamate derivatives from carbon
disulfide and amines without any addition of bases or probases. But, as
we shall see below, primary and secondary amines behave differently.
Indeed, Feroci et al. reported the use of electrogenerated
cyanomethyl anion to access to the corresponding alkyl carbonates,
alkyl carbamates and oxazolone derivatives26−29 following the conden-
sation of alcohols, amines and 1,4-aminoalcohols, respectively. They
also showed a new route to obtain asymmetric oxazolones from α,β-
unsaturated nitroalkenes.30,31
It is well known, that the electrolysis of acetonitrile at imposed cur-
rent in the presence or the absence of probases [PBs] such as azoben-
zene, aromatic aldehydes, ketones and aryl halides,32−34 leads to the
formation of the cyanomethyl anion (Scheme 1). The resulting electro-
generated anion/base [EGB] can induce the deprotonation of primary
or secondary amines35−36 to yield an excellent nucleophilic agent and
regenerate acetonitrile.
RESULTS AND DISCUSSION
The electrolysis of acetonitrile under galvanostatic conditions (I = 28–
30 mA) in a divided cell in the presence of tetrabutylammonium per-
chlorate (0.1 mol/L) as supporting electrolyte and a copper plate cathode
yields the cyanomethyl carbanion. This anion is a base strong enough

Synthesis of Dithiocarbamate Acid Esters
2479
SCHEME 1
(pKa = 31.3 in DMSO32) to deprotonate most primary or secondary
amines yielding acetonitrile and the amide anion.
When a secondary amine is used, the resulting amide anion acts
as a nucleophile towards carbon disulfide allowing the electrochemical
synthesis of dithiocarbamates 1 on addition of an alkyl halide such
as ethyl iodide, methyl iodide or benzyl iodide (Scheme 1). It should
be noted that carbon disulfide (Ep/Hg = −0.99 V vs Hg),37 which is
much more readily reduced than acetonitrile (Ep/Pt = −(3.4 − 3.5) V
vs Ag/Ag+ for MeCN-Bu4NBF4 and MeCN-LiClO4),26a,32 must be added
after the end of the electrolysis.
The behavior of the anions formed from the respective amines is in
accordance with that reported previously for the reaction with carbon
dioxide as electrophile.26,27,38
The dithiocarbamate 1 is isolated as the major product along with
alkyl or benzyl 3-amino-2-cyanodithiocrotonate 2 as a by-product
(Scheme 2, Table I). The latter results from the condensation of the
cyanomethyl anion with acetonitrile (Thorpe-like reaction) leading to
the stable 3-iminobutanenitrile anion.26,34 This anion reacts with car-
bon disulfide. Compound 2 is formed after alkylation of the resulting
adduct by the alkyl or benzyl halide (Scheme 2), which is introduced in
the cathodic solution. 1H, 13C NMR and MS spectra are consistent with
the formula of 2 shown in Scheme 2 (see Experimental section for 2,
R3 = Et). Moreover, only one stereoisomer is observed for 2, which is the
Z-isomer. This is corroborated by the appearance of two different N-H
resonances in the 1H NMR spectrum, the more deshielded one at 12.6
ppm corresponding to a particularly strong stabilizing intramolecular
. . .
N H S C hydrogen bond. This structure is in accordance with that
previously characterized by spectroscopic data (IR, 1H, 13C, 15N NMR)
and X-ray crystal structure analyses.39

2480
M. Toumi et al.
SCHEME 2
Compared to secondary amines, primary amines act differently (Ta-
ble I). Surprisingly, the electrogenerated (−)CH2CN/primary amine/CS2
system gives the (Z)-3-(N-substituted-amino)-2-cyanodithiocrotonates
3 as the major products (Scheme 3).
The structure of 3 is corroborated by the following spectroscopic data,
all showing the presence of only one stereoisomer (see also Table I and
the Experimental section):
a. 1H NMR: when R3 = PhCH2 (in 3a and 3b), 3-pyCH2 (in 3d) and
PhCH(CH3) (in 3c), the CH2 an CH signals appear as a doublet
(at 4.65 ppm) and a quintet (at 5.2 ppm), respectively, showing a
coupling with one NH proton. Furthermore, the NH signal for all
products 3 is extremely deshielded (14 ppm for 3a–3d, 3g and 15 ppm
3
. . .
when R = Ar), which indicates a strong intramolecular N H S C
hydrogen bond that stabilizes the Z diastereomer.
b. 13C NMR: all signals fit the structure 3; in particular the signals at
118 ppm (C N), around 94 ppm (Cb) and 167 ppm (Cc) are charac-
teristic of a N C C system (e.g. Me2N CH CH2, δCH2 = 91.3 ppm
and δCH = 151.3 ppm),40 as well as the signals at 209 ppm (C S),
127–134 ppm (Car) and those corresponding to CS2Et, CS2Me, and
CS2CH2Ph, respectively.
c. All Mass spectra are consistent with structure 3.
d. The IR spectra of 3c exhibit a medium broad N-H band at 3150
cm−1 corresponding to a strong intramolecular N H S C hydro-
. . .
gen bond and a sharp band at 2195.7 cm−1 corresponding to a con-
jugated C N bond.
e. An X-ray crystal structure analysis of 3c, which will be published
elsewhere, undoubtedly supports this structure.41

Synthesis of Dithiocarbamate Acid Esters
2481
TABLE I Preparation of Compounds 1 and 3. Reaction Conditions:
Cu Cathode, Graphite Anode; CH3CN/0.1 M TBAP; Ethyl Iodide as
Alkylating Agent (R3 = Et)
Electricity consumptionb)
Starting amine
Isolated product
Yielda)(%)
47
(F.mol−1
)
1a
1.0
1b
1c
43
54
1.5
1.0
1d
1e
47
28
1.0
1.2
1fc)
2
21
1.0
1.1
e)
e)
2
1.0
3a
3bd)
3c
60
54
47
2.0
2.0
2.0
(Continued on next page)

2482
M. Toumi et al.
TABLE I Preparation of Compounds 1 and 3. Reaction Conditions:
Cu Cathode, Graphite Anode; CH3CN/0.1 M TBAP; Ethyl Iodide as
Alkylating Agent (R3 = Et) (Continued)
Electricity Consumptionb)
Starting amine
Isolated product
Yielda)(%)
15
(F.mol−1
)
3d
2.0
3e
3f
50
46
40
2.0
2.0
2.0
C12H25NH2
3gc)
a)The yield of isolated dithiocarbamates is based on the starting amine; b)The
electricity consumption represents the number of Faradays per mole of amines supplied
to the electrode. c)The alkylating agent R3X is benzyl bromide; d)The alkylating agent
R3X is methyl iodide; e)At the end of electrolysis only the compound 2 was isolated. This
is certainly in relation with too large pKa values for diisopropylamine (35,7 in THF42
and DMSO43) and iminodibenzyl relatively to that of acetonitrile.
Finally, as for the cyanomethyl anion, the primary amide anions
R1NH−, less hindered than the secondary ones, form very loose solvent-
separated ion pairs with the ammonium cations in the polar solvent
MeCN. This renders them sufficiently nucleophilic to add to MeCN
molecules.
The following mechanism can thus be proposed to explain the forma-
tion of 3 (Scheme 3):
a. the amide anion A reacts with acetonitrile to give the intermediate
amidine anion B; b. acetonitrile exchanges a proton with B to form the
amidine C and the cyanomethyl anion; c. the latter adds to amidine C
to give the amide anion D, which isomerizes into the carbanion E; d.
spontaneous elimination of ammonia gives the cyanomethylen anion F;
e. the latter adds to carbon disulfide and the formed dithiocarboxylate
anion is trapped by the alkyl halide; f) and finally, the iminocyanodithio-
carboxylate isomerizes into the more conjugated (Z)-3-(N-substituted-
amino)-2-cyanocrotonate 3, which is also stabilized by an intramolecu-
lar hydrogen bond.
In summary, the cyanomethyl EGB / amine / carbon disulfide / alkyl
or benzyl halide system—easily prepared at room temperature and

Synthesis of Dithiocarbamate Acid Esters
2483
SCHEME 3
constant current in a divided cell with TBAP as supporting electrolyte—
appears to be convenient for the preparation of dithiocarbamates when
starting from secondary amines and (Z)-3-(N-substituted-amino)-2-
cyanocrotonates when starting from primary amines.
EXPERIMENTAL
Apparatus and Materials
Melting points were determined on an Electrothermal 9100 apparatus
1
and are uncorrected. The H and 13C NMR spectra were recorded in
CDCl3 solution with a Bruker AC 300 spectrometer operating at 300
1
MHz for H and at 75 MHz for 13C. Chemical shifts are in ppm, with
respect to tetramethylsilane (TMS) as internal standard. Mass spec-
tra were recorded with a JEOL MS 700 system in chemical ionization
mode using NH3 or CH4 and with a MAT Finnigan 90 apparatus for
EIMS. Coupled GC/MS analyses were performed in electronic ioniza-
tion form with a Finnigan integrated spectrometer. The IR spectrum
was recorded with a Perkin-Elmer Paragon 1000 FT/IR spectrometer.
All reagents were commercially available and were used without fur-
ther purification.

2484
M. Toumi et al.
General Procedure
The electrolysis was carried out under galvanostatic conditions (I =
28–30 mA) at a Cu cathode (area: 50 cm2) and a graphite anode in a
divided cell under nitrogen atmosphere at room temperature with 0.1 M
TBAP-MeCN as supporting electrolyte. The starting amount of primary
and secondary amines was close to 5 mmol. After the consumption of
1 or 2 F/mol with respect to the amine (see Table I), 5 mmol of carbon
disulfide was added into the cathodic solution and the reaction mixture
was stirred at room temperature for 1 h. The alkylation was then carried
out in the presence of an excess (1.1–1.2 equivalent) of alkyl halide R3-X
(X = I, Br) overnight under stirring.
The solvent MeCN was removed under vacuum and the residue ex-
tracted with diethyl ether (3 × 30 mL). The organic phase was then
washed with 100 mL of water, dried over MgSO4, filtered, and diethyl
ether was evaporated. Separation of the products was accomplished by
column chromatography (silica gel 60, Fluka) using a 9 : 1 mixture of
hexane/AcOEt as eluent.
Isolated Products
1a
1
3
Yellow oil; H NMR (CDCl3): δ 1.40 (t, J = 7 Hz, 3H, Ha); 3.30 (q,
3 J = 7 Hz, 2H, Hb); 6.45 (s, 1H, He); 7.78 (s, 1H, Hf); 8.60 (s, 1H, Hd). 13
C
NMR (CDCl3): δ 12.3 (Ca); 30.6 (Cb); 110.2 (Ce); 129.9 (Cf); 144.5 (Cd);
200.7 (Cc S). MS (EI): m/z (%): 172 (100) (M+.); 139 (40) (M – HS)+; 113
(35); 112 (65); 111 (40) (M – SC2H5)+; 105 (20) (CSSEt)+; 104 (35); 103
(25); 84 (35); 77 (40); 69 (40); 68 (95) (M + H − CS2C2H5)+; 60 (45); 59
(35); 57 (20).
1b
1
3
Yellow oil; H NMR (CDCl3): δ 1.45 (t, J = 7 Hz, 3H, Ha); 3.35 (q,
3 J = 7 Hz, 2H, Hb); 7.11 (s, 1H, He); 7.78 (s, 1H, Hf); 8.50 (s, 1H, Hd). 13
C
NMR (CDCl3): δ 12.4 (Ca); 31.3 (Cb); 117.7 (Ce); 131.2 (Cf); 135.5 (Cd);
198.0 (Cc S). MS (EI): m/z (%): 172 (70) (M+ ); 111 (22) (M – SC2H5)+;
.
105 (100) (CSSEt)+; 84 (35); 77 (60); 68 (20) (M + H – CS2C2H5)+; 60
(10); 57 (15).

Synthesis of Dithiocarbamate Acid Esters
2485
1c
Orange, viscous oil; 1H NMR (CDCl3): δ 1.45 (t, 3 J = 7 Hz, 3H, Ha);
3.40 (q, 3 J = 7 Hz, 2H, Hb); 7.25 (t, 3 J = 6.5 Hz, 2H, Hg); 7.40 (t, 3 J = 6.5
Hz, 2H, Hf); 7.90 (d, 3 J = 6.5 Hz, 2H, He), 8.40 (d, 3 J = 6.5 Hz, 2H, Hh).
13C NMR (CDCl3): δ 12.9 (Ca); 32.2 (Cb); 115.3 (Cg); 120.0 (Cf); 123.4
(Ce); 125.9 (Ci); 126.8 (Ch); 140.1 (Cd); 202.9 (Cc S). CI-MS (NH3): m/z
(%): 289 (20) (M + H + NH3)+; 272 (85) (M + H)+; 212 (80); 210 (25) (M
+ H − SC2H5); 168 (100) (M + H + 2H − CS2C2H5); 167 (25); (M + H
− CS2C2H5)+. CI HRMS (CH4) m/z (%): 272.0564 (M+H)+.
1d
Solid; m.p.: 88–89◦C; 1H NMR (CDCl3): δ 1.42 (t, 3 J = 7 Hz, 3H, Ha);
3
3.30 (q, J = 7 Hz, 2H, Hb); 7.37 (t, Hg); 7.57 (t, Hf); 7.72 (d, He); 8.17
(s, Hj); 9.12 (d, Hh). 13C NMR (CDCl3): δ 12.5 (Ca); 29.8 (Cb); 116.8 (Cg);
121.4 (Cf); 125.2 (Ce); 127.6 (Ci); 130.3 (Cj); 139.9 (Ch); 140.3 (Cd); 199.7
(Cc S). MS (EI): m/z (%): 222 (74) (M+.); 194 (20) (M − C2H2)+; 189 (15);
162 (86); 161 (46) (M − SC2H5)+; 134 (28); 129 (30); 118 (100) (M + H
− CSSEt); 105 (34) (CSSEt)+; 102 (20); 91 (18); 77 (30); 63 (18); 50 (10).
1e
Solid; m.p.: 40.4◦C; 1H NMR (CDCl): δ 1.28 (t, 3 J = 7.2 Hz, 3H, Ha);
3.23 (q, 3 J = 7.2 Hz, 2H, Hb); 3.67 (t, br, 4H, Hd); 3.8–4.3 (br, 4H, He). 13
C
NMR (CDCl3): δ 13.7 (Ca); 31.2 (Cb); 50.6 (Cd); 66.1 (Ce); 197.4 (Cc S).
CI MS (NH3): m/z (%): 192 (100), (M + H)+; 132 (65); 130 (32) (M −
HSC2H5)+. CI HRMS (CH4): 192.025 (55) (M+H)+.
1f
1H NMR (CDCl3): δ 1.25 (t, 3 J = 7 Hz, 6H, Ha,e); 3.65 (q, 3 J = 7 Hz,
2H, Hb,d); 4.00 (q, 3 J = 7 Hz, 2H, Hb,d); 4.52 (s, 2H, Hf); 7.15–7.4 (m, 5H,

2486
M. Toumi et al.
Har). 13C NMR (CDCl3): δ 11.6 (Ca,e); 12.5 (Ca,e); 42.1 (Cf); 46.7 (Cb,d);
49.4 (Cb,d); 127.4 (Cj); 128.4 (Ch,i); 129.5 (Ch,i); 136.1 (Cg); 195.0 (Cc = S).
2
1
(R3 = Et, Z-isomer): Yellow solid; m.p.: 147◦C; H NMR (CDCl3): δ
1.36 (t, 3 J = 7.3 Hz, 3H, Hk); 2.41 (s, 3H, Hd); 3.23 (q, 3 J = 7.3 Hz, 2H,
Hl); 6.6 (br, 1H, NH); 12.6 (br, 1H, intramolecularly bonded NH). 13C
NMR (CDCl3, DMSO): 13.0 (Ck); 23.0 (Cd); 27.6 (Ci); 92.7 (Cb); 118.1
(Ce ≡N); 169.4 (Cc); 207.9 (Ca S). CI MS (NH3): m/z (%): 204 (100) (M
+ H + NH3)+; 187 (75), (M + H)+; 172 (13), (M + H – CH3)+; 144 (13), (M
– CH3CNH3)+; 127 (13) (M – SCH=CH2)+. CI HRMS (CH4): 187.036
(M+H)+.
3a
1
(R3 = Et, Z-isomer): Yellow solid; m.p.: 105◦C; H NMR (CDCl3): δ
1.30 (t, 3 J = 7 Hz, 3H, Hk); 2.40 (s, 3H, Hd); 3.20 (q, 3 J = 7 Hz, 2H,
Hi); 4.65 (d, J = 6 Hz, 2H, Hf); 7.20–7.40 (m, 5H, Har); 14.1 (br, 1H,
intramolecularly bonded NH). 13C NMR (CDCl3): δ 12.8 (Ck); 19.3 (Cd);
28.6 (Cl); 48.4 (Cf); 94.3 (Cb); 118.7 (Ce ≡N); 127.2 (Ch,i); 128.3 (Cj);
129.2 (Ch,i); 134.8 (Cg); 167.5 (Cc); 209.3 (Ca S). CI MS (C4H10): m/z
(%): 277 (100), (M + H)+; 243 (4) (M + H – H2 S)+; 215 (15) (M - EtSH)+;
171 (21) (M + H - CS2Et)+.
3b
(R3 = Me, Z-isomer): Yellow solid; m.p.: 105.3◦C; 1H NMR (CDCl3): δ
2.40 (s, 3H, Hd); 2.60 (s, 3H, Hl); 4.65 (d, 3 J = 6 Hz, 2H, Hf); 7.20–7.45 (m,
5H, Har); 14.1 (br, 1H, intra-molecularly bonded NH). 13C NMR (CDCl3,
DMSO): δ 17.9 (Cl); 19.3 (Cd); 48.4 (Cf); 101.8 (Cb); 118.7 (Ce ≡N); 127.1
(Ch,i,j); 128.3 (Ch,i,j); 129.2 (Ch,i,j); 134.9 (Cg); 167.0 (Cc); 210.0 (Ca S).
CI MS (C4H10): m/z (%): 263 (100), (M + H)+; 236 (4) (M + H – HCN)+;
215 (27), (M + H – MeSH)+; 192 (18); 171 (M + H – CS2Me)+.
3c
1
3
(R3 = Et, Z-isomer): m.p.: 81◦C; H NMR (CDCl3): δ 1.30 (t, J = 7
Hz, 3H, Hk); 1.60 (d, 3 J = 6 Hz, 3H, Hm); 2.36 (s, 3H, Hd); 3.20 (q, 3 J = 7

Synthesis of Dithiocarbamate Acid Esters
2487
Hz, 2H, Hl); 5.2 (quint, 3 J = 6 Hz, 1H, Hf); 7.20–7.50 (m, 5H, Har); 14.1
(br, d, 3 J = 6 Hz, 1H, intramolecularly bonded NH). 13C NMR (CDCl3+
DMSO): 12.9 (Ck); 19.2 (Cd); 23.3 (Cm); 27.6 (Cl); 54.6 (Cf); 93.5 (Cb);
118.1 (Ce ≡N); 125.9 (Ch,i); 127.8 (Cj); 129.0 (Ch,i); 141.3 (Cg); 167.5
(Cc); 206.6 (Ca S). MS (EI): m/z (%): 290 (10) (M+.); 261 (6) (M – Et)+;
229 (18) (M – SEt)+; 196 (4); 185 (14) (M – CSSEt)+; 125(13); 105 (100)
(PhCHCH3)+; 77 (18) (Ph)+; 42 (4). CI HRMS (CH4): 291.099 (M+H)+.
IR (NaCl): ν (cm−1) = 3150 (m, broad, intramolecularly bonded NH),
3020, 2950, 2925, 2852, 2195 (conjugated C N), 1600 (S, conjugated
C=C, Car-Car), 1447, 1400, 1354, 1324, 1261 (S, conjugated C-N), 1240
(C-N), 1090 (C= S), 1023, 964, 806 (S), 753, 702, 553.
3d
(R3 = Et, Z-isomer): Solid; m.p.: 153.8◦C; 1H NMR (CDCl3): δ 1.30 (t,
3 J = 7 Hz, 3H, Hk); 2.40 (s, 3H, Hd); 3.10 (q, 3 J = 7 Hz, 2H, Hl); 4.65 (d,
2H, Hf); 7.20–8.70 (m, 5H, Har); 14.1 (br, 1H, intramolecularly bonded
NH). 13C NMR (CDCl3): δ 12.7 (Ck); 19.4 (Cd); 28.8 (Cl); 49.0 (Cf); 118.5
(Ce ≡N), 128.0 (Ci); 135.0 (Cg); 137.0 (Cm); 148.4 (Cj); 149.0 (Ch); 167.5
(Cc); 210.2 (Ca S).
3e
(R3 = Et, Z-isomer): Solid; m.p.: 105◦C; 1H NMR (CDCl3): δ 1.35
(t, 3 J = 7 Hz, 3H, Hk); 2.40 (s, 3H, Hd); 3.25 (q, 3 J = 7 Hz, 2H, Hl);

2488
M. Toumi et al.
7.30–7.60 (m, 5H, Har); 15.1 (br, 1H, intra-molecularly bonded NH). 13
C
NMR (CDCl3, DMSO): δ 12.8 (Ck); 20.3 (Cd); 27.8 (Cl); 94.4 (Cb); 117.7
(Ce ≡N); 125.5 (Ck); 128.1 (Cj); 129.6 (Ci); 135.5 (Cg); 167.3 (Cc); 207.7
(Ca S).
3f
1
(R3 = Et, Z-isomer): Solid; m.p.: 101.6◦C; H NMR (CDCl3): δ 1.40
(t, 3 J = 7 Hz, 3H, Hk); 2.35 (s, 3H, Hd/m); 2.40 (s, 3H, Hd/m); 3.25 (q,
3 J = 7 Hz, 2H, Hl); 7.10-7.30 (m, AA’BB’, 4H, Hg, Hi); 15.1 (br, 1H, in-
tramolecularly bonded NH). 13C NMR (CDCl3): δ 12.7 (Ck); 20.4 (Cd/m);
21.1 (Cd/m); 28.8 (Cl); 94.7 (Cb); 118.4 (Ce ≡N); 125.5 (Ch); 130.3 (Ci);
133.4 (Cj); 138.4 (Cg); 166.2 (Cc); 210.1 (Ca S). MS (EI): m/z (%): 276
(26) (M+.); 247 (45) (M – Et)+; 215 (100) (M – SEt)+; 182 (7); 132 (10);
107(18) (CH3C6H4NH2)+; 91 (33) (C7H7)+; 65 (22).
3g
(R3 = Ph-CH2, Z-isomer): Orange solid; m.p.: 50.3◦C; 1H NMR
(CDCl3): 0.90 (t, 3 J = 7 Hz, 3H, Hn); 1.2 – 1.5 (m, 18H, Hm); 1.72 (quint,
3 J = 7 Hz, 2H, Hl); 2.40 (s, 3H, Hd); 3.45 (q, 3 J = 7 Hz, 2H, Hk); 4.50 (s,
2H, Hf); 7.20–7.40 (m, 5H, Har); 13.7 (br, 1H, intramolecularly bonded
NH ). 13C NMR (CDCl3): 14.1 (Cv); 19.1 (Cd); 22.7 (Cu); 26.8 (Ct); 28.9
(Cs), 29.1 (Cr); 29.3 (Cp, Cq), 29.5 (Cn, Co); 29.6 (Cm); 31.9 (Cl); 38.9 (Cf);
45.0 (Ck); 93.7 (Cb); 118.7 (Ce N); 127.4 (Cj); 128.5 (Ch,i); 129.4 (Ch,i);
135.6 (Cg); 167.3 (Cc); 207.6 (Ca S). MS (EI): m/z (%): 416 (5) (M+.);
325 (76) (M – Ph-CH2)+; 293 (100) (M – PhCH2 S)+; 157 (10); 91 (88)
(C7H7)+; 43 (23). CI MS (NH3): m/z (%): 434 (100), (M + H + NH3)+;
417 (85) (M + H)+; 344 (53); 325 (48) (M + H – PhCH2)+; 295 (54); 293
(18) (M + H – PhCH2 S)+; 251 (15); 200 (22); 186 (68); 108 (35).
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