Vol. 25, No. 2 (2013)
Synthesis of Derivatives of Di-butyldithiocarbamates 963
reasons, the synthesis of the dithiocarbamates in one-pot
reaction from dialkylamines, carbon disulfide, phenacylbromide
in presence of anhydrous sodium acetate, because this method
is safe, high yield, short time reaction, low reaction temperature
and availability of raw material. Scheme-II shows the general
reaction equation.
100 mmol sodium hydroxide (4 g) in 175 mL pure methanol
and is added dropwise 100 mmol of carbon disulfide (7.6 g,
6.022 mL) to the stirred reaction mixture at room temperature.
After finished adding CS2 stirring is continued for 1 h. Then
the reaction mixture is or was left to the next day and then is
evaporated. The di butyl- dithiocarbamates sodium salts is
formed.
O
R1
C
Br
N
H
+
+
CS2
CH3CH2CH2CH2
Ar
C
H2
R2
NH
+
CS2
+
NaOH
CH3CH2CH2CH2
S
H2
CH3COONa
R1
R2
C
C
Ar
S
CH3CH2CH2CH2
CH3CH2CH2CH2
N
S
C
–NaBr
–CH3COOH
N
C
S
Na+
O
R1, R2 = C4H9; Ar = –C6H5, –C6H3Cl2
Scheme-II
Spectral data of compound 1a: As yellow solid, yield
80 %, m.p. 50 °C, Ms 227 g/mol; IR (KBr, νmax, cm-1): 3100,
2850, 1464, 1367,1250, 924, 543. 1H NMR (300 MHz, CDCl3):
δ = 0.98 (m, 2(-CH3) of C4H9), 1.26-1.58 (m, 2(-CH2-) near
of-CH3), 1.62-1.68 ( m, 2(-CH2-)), 4.28 (s, 2 (-CH2-) near of
N) ppm.
In this paper, we reported the synthesis of N-dibutyl-
dithiocarbamate, which contains the CH-acid group and electron
accepting group such as sulfur group and then studied the
reaction of these compounds with carbon disulfide in the liquid
heterogeneous phase, to give derivatives of dibutyldithio-
carbamate and sodium dithiocarbamate salt.
Preparation of phenacyl-dibutyl-dithiocarbamates
(C17H25NOS2) (1b): To a solution of 103 mmol (8.45 g) anhy-
drous sodium acetate, 103 mmol (13.287 g, 17.529 mL) dibutyl
amine as the secondary amine and 103 mmol (10.18 g) carbon
disulfide in 175 mL of absolute methanol was added dropwise
103 mmol (20.5 g) of an alkylating agent as phenacylbromide
in 50 mL of absolute methanol. The solution left overnight at
room temperature. Wherein the phenacyl-dialkyl-dithiocarba-
mates precipitate.The precipitate was filtered off and washed
several times with a little water to separate sodium halide.
EXPERIMENTAL
Glassware were cleaned and dried in the dryer (Ecocell)
at 100 ºC before use. Solvents were evaporated under reduced
[9R-125-B:491(Büchi)] at temperature < 45 ºC. Thin layer
chromatography (TLC) was performed using siliga gel 60F-
254 plates with I2 vapours as detecting agents followed by
spraying with Draggendorff reagent. TMS was used as an
internal standard in 1H NMR in CDCl3. Infrared spectra were
recorded as KBr pellets by FT/IR-400 (Jasco) spectrometer.
Melting points were determined on a melting point apparatus.
Unless chemicals were obtained with high purity from (Merck,
Panreac, Sep) and were used without further purification.
General procedure for the preperation of phenacyl-
bromide: Into a 500 mL three-necked flask with stirrer, reflux
condenser, dropper funnel dropwise and calcium chloride tube
was added to a solution of 0.5 mol acetophenone in 100 mL
glacial acetic acid with a few drops of hydrogen bromide/
glacial acetic acid and dropped 0.5 mol of bromine to be
increased so that the temperature maintained at ca. 20 ºC (at
first reaction can occur in transition). When it is cooled in ice
water. If no one is crystallizing, it poured into ice water. The
solid compounds extracted and washed with 50 % alcohol until
they are colourless. It crystallized from alcohol to pure crys-
talline compound.
O
C
CH2
Br
CH3CH2CH2CH2
CH3CH2CH2CH2
NH
+ CH3COONa + CS2
S
O
C
CH3CH2CH2CH2
CH3CH2CH2CH2
N
C
S
CH2
Spectral data of compound 1b:As blancsale solid, yield
81.7 %, m.p. 49.2 ºC, Ms 323 g/mol; IR (KBr, νmax, cm-1):
1
3050, 2850, 1750, 1600, 1484, 1351, 1207, 1100, 744. H
NMR (300 MHz, CDCl3): δ 0.98 (m, 2(-CH3) of C4H9), 1.43-
1.9 (m, 4(-CH2-) of C4H9), 3.7-3.9 (m, 2(-CH2-) near of N),
4.88 (s,(-CH2-)), 7.2-8.07 (m,-C6H5) ppm.
Preparation of (1-benzoyl-2,2-dibutylthio)vinyl-
dibutyldithiocarbamates (C26H41NOS4) (1c): To a solution
of 5 mmol (1.48 g) (1b) in 5 mL carbon disulfide and 5 mL
chloroform is added with efficient stirring a mixture of 20
mmol (1.12 g) potassium hydroxide and 10 mmol (2.3 g)
triethylbenzyl ammonium chloride (TEBA chloride) in 10 mL
water. After 10 min at room temperature 15 mmol (2.5 mL)
butyl iodide is added dropwise and stirring is continued for
1 h. The phases are separated and the organic layer is washed
with water and dried over anhydrous calcium chloride. The
O
C
O
C
–HBr
Br2
R
CH3
R
CH2
Br
+
HBr + CH3COOH
Preparation of di butyl-dithiocarbamates sodium salts
(C9H18NS2Na) (1a): Into a 250 mL two-necked flask with
stirrer, dropwise is added of 100 mmol (12.9 g) di-butylamine,