Synthesis and reactivity of mannich bases. XVIII. Reaction of dithiocarbamic acid salts with Mannich bases derived from ortho- hydroxyacetophenones

Article abstract of DOI:10.1080/714040961

The reaction of Mannich bases derived from ortho-hydroxyacetophenones with N,N-dialkyldithiocarbamic acid salts result in the formation of the corresponding dithiocarbamic acid esters via an amine moiety replacement when the process is conducted in cold w

Full text of DOI:10.1080/714040961

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Synthesis and Reactivity of Mannich Bases. XVIII.
Reaction of Dithiocarbamic Acid Salts With Mannich
Bases Derived from Ortho-Hydroxyacetophenones
Gheorghe Roman a , Eugenia Comanita b & Lucia Dumitrescu a
a Transilvania University, Brasov, Romania
b Gh. Asachi Technical University, Iasi, Romania
Published online: 18 Jun 2010.
To cite this article: Gheorghe Roman , Eugenia Comanita & Lucia Dumitrescu (2003) Synthesis and Reactivity of Mannich
Bases. XVIII. Reaction of Dithiocarbamic Acid Salts With Mannich Bases Derived from Ortho-Hydroxyacetophenones,
Phosphorus, Sulfur, and Silicon and the Related Elements, 178:11, 2479-2490, DOI: 10.1080/714040961
To link to this article: http://dx.doi.org/10.1080/714040961
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Phosphorus, Sulfur, and Silicon, 178:2479–2490, 2003
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Copyright Taylor & Francis Inc.
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500390235677
SYNTHESIS AND REACTIVITY OF MANNICH BASES.
XVIII. REACTION OF DITHIOCARBAMIC ACID
SALTS WITH MANNICH BASES DERIVED FROM
ORTHO-HYDROXYACETOPHENONES
Gheorghe Roman,a Eugenia Comanita,b and Lucia Dumitrescua
Transilvania University, Brasov, Romaniaa and Gh. Asachi
Technical University, Iasi, Romaniab
(Received April 10, 2003)
The reaction of Mannich bases derived from ortho-hydroxyaceto-
phenones with N,N-dialkyldithiocarbamic acid salts result in the
formation of the corresponding dithiocarbamic acid esters via an
amine moiety replacement when the process is conducted in cold
water. Attempts to carry out the synthesis in refluxing ethanol-
water mixture led to the insertion of carbon sulfide at the C N
bond in Mannich bases. N-Aryldithiocarbamic acid salts afforded
on reaction with the above-mentioned Mannich bases only bis-(2-(2-
hydroxybenzoyl)ethyl)thioethers.
Keywords: Dithiocarbamates; exchange reaction; Mannich bases;
ortho-hydroxyacetophenones; S-alkylation
The replacement of the amine group in Mannich bases, which also may
be formally regarded as an x-alkylation of a nucleophilic reactant XH
by the R CH2 moiety of the Mannich base, is one of the most syntheti-
cally valuable feature of these compounds’ chemistry.1−3 S-Alkylations
with Mannich bases provide an easy access to thioethers, thiocarbamic
acid esters, sulfones, etc., frequently displaying structures otherwise
difficultly to obtain. As it concerns the preparation of dithiocarbamic
esters from Mannich bases, the retrosynthetic analysis shows a sec-
ond possible way, namely the insertion of CS21 between the methylene
and the amino group in Mannich bases (b), besides the replacement of
the amine group by a dithiocarbamate anion in an aminomethylation
product (a) (Scheme 1).
Address correspondence to Gheorghe Roman, National Research Council, Biotech-
nology Research Institute, 6100 Royalmount Avenue, H4P 2R2, Montre´al, Quebe´c,
Canada.
2479

2480
G. Roman et al.
SCHEME 1 Retrosynthetic analysis for the synthesis of dithiocarbamic esters
derived from Mannich bases.
The former way usually is employed when Mannich bases are easily
available as salts (the case of β-aminoketones) and exceeds the latter
route in versatility as it allows the preparation of a wide range of var-
iously N-substituted and N,N-disubstituted dithiocarbamates. Discon-
nection b may be adopted in the case of Mannich bases as free amines
(that readily result from phenols, for example) and produces only dithio-
carbamic esters that retain the amine group in the initial Mannich base.
Both procedures have been scarcely used4−7 for the preparation of such
esters that may act as fungicides4 or as antioxidizing agents.8
Continuing our investigation on the replacement of the amine group
in β-aminoketones with nucleophiles,9−15 this article explores the reac-
tion between Mannich bases derived from ortho-hydroxyacetophenones
and several dithiocarbamic acid salts. The choice of this particular type
of Mannich bases is justified if one takes into account the ability of the
resulting dithiocarbamic esters to form with transitional metal cations
the complexes 2 (MeII = Cu2+, Zn2+, Ni2+, etc), which may exhibit an
enhanced potential fiuigitoxic activity when compared to the ligands 1.
RESULTS AND DISCUSSION
N,N-Dialkyldithiocarbamic acid salts 4a–d reacted with Mannich bases
derived from ortho-hydroxyacetophenones 3 and offered easy access to
the expected dithiocarbamic acid esters 1a–h, as described in Scheme 2.
S-Alkylations may proceed either by a nucleophilic substitution
mechanism or via a tandem elimination-addition mechanism, as in
the case of an amine exchange reaction. In the first approach, the

Synthesis and Reactivity of Mannich Bases
2481
SCHEME 2 Synthesis of S-(2-(2-hydroxybenzoyl)ethyl)dithiocarbamates
from the reaction of Mannich bases derived from ortho-hydroxyacetophenones
and N,N-dialkyldithiocarbamic acid salts.
nucleophilic dithiocarbamate anion may attack the easily displaceable
amino moiety of the Mannich base in a classical SN2 mechanism. The
second alternative involves the formation of an α, β-unsaturated ke-
tone after the elimination of the amine hydrochloride, followed by the
addition of the dithiocarbamate anion (Scheme 3).
The reaction has been conducted in water at room temperature. By
simply adding the solution of the N,N-dialkyldithiocarbamic acid salt
4a–d to the solution of the Mannich base hydrochloride 3, an emul-
sion started to form that later turned into a solid. In most cases, a
reaction period of three to four hours offered the necessary time for
crystals’ formation in a reasonable yield. However, as in the case of

2482
G. Roman et al.
SCHEME 3 Alternative bimolecular nucleophilic substitution and elimina-
tion-addition pathways leading to esters 1.
amine exchange reaction of Mannich bases with piperazines,13 it has
been noticed that the longer the reaction times the better the yields
and the purer the reaction products. The yields of the pure esters are
dramatically lowered after recrystallization (from 70–80% to 30–40%).
Previous studies have shown that N-alkylations with ketonic
Mannich bases occur smoothly in a 1:1 (v/v) ethanol-water mixture at
reflux when arylamines9,10 or NH-heterocycles12,14,15 were employed as
nucleophiles. Reaction of 3-(dimethylamino)-l-(2-hydroxy-5-methyl-
phenyl)propan-1-one hydrochloride 3b and sodium N,N-diethyldithio-
carbamate was also attempted under the same conditions. In this case,
the reaction product was not the expected S-(2-(2-hydroxy-5-methyl-
benzoyl)ethyl)-N,N-diethyldithiocarbamate, but S-(2-(2-hydroxy-5-
methylbenzoyl)ethyl)-N,N-dimethyldithiocarbamate 1j, that may have
resulted by the insertion of carbon disulfide to the C N bond in
Mannich base (Scheme 4). Moreover, when 1-(2-hydroxyphenyl)-3-
(4-morpholinyl)-1-propanone hydrochloride11 and ammonium N-(2-
methylphenyl)dithiocarbamate 4f were reacted in aqueous ethanol at
SCHEME 4 S-(2-(2-Hydroxybenzoyl)ethyl)dithiocarbamates from the in-
sertion of CS2 at C N bond in Mannich bases derived from ortho-
hydroxyacetophenones.

Synthesis and Reactivity of Mannich Bases
2483
reflux, the insertion of carbon disulfide occurred to produce a sub-
stance presenting the same physical and spectroscopic features as the
dithiocarbamic ester 1c, resulted from the S-alkylation of 4-morpho-
linecarbodithioic acid salt with dimethylamine Mannich base at room
temperature. Carbon disulfide was probably generated in situ from
the partial decomposition of the dithiocarbamic acid salt on boiling,
thus accounting for the modest yields recorded. A similar result was
previously noted when β-morpholinopropiophenone hydrochloride was
reacted with carbon disulfide in aqueous ammonia.4
Ammonium N-phenyldithiocarbamate 4e gave on treatment with
Mannich bases 3a,b in water at room temperature the symmetrical
thioethers 5a,b, and not the expected dithiocarbamic esters (Scheme 5).
Reaction of 3-dimethylamino-1-(2-hydroxyphenyl)propan-1-one hydro-
chloride 3a either with ammonium N-(2-methylphenyl)dithiocarba-
mate 4f or with triethylammonium N-(2-pyridyl)dithiocarbamate 4g
afforded the same thioether 5a having two identical 2-hydroxyben-
zoylethyl) radicals. In a similar manner, 3-dimethylamino-l-(2-hydroxy-
5-methylphenyl)propan-l-one hydrochloride 3b provided access only to
bis-[2-(2-hydroxy-5-methylbenzoyl)ethyl]thioether 5b regardless of the
N-aryldithiocarbamic acid salt 4e–g employed in the reaction.
SCHEME 5 Synthesis of thioeters 5 from Mannich bases derived from ortho-
hydroxyacetophenones and salts of N-aryldithiocarbamic acids.
IR spectra recorded for all newly synthesized esters 1 and thioethers
5 exhibit a strong νC peak at 1650 cm−1, corresponding to a carbonyl
O
group involved in a hydrogen bond with the neighbouring phenolic hy-
droxyl. Several other medium to strong IR absorption bands were also
identified and attributed to the dithiocarbamate remainder in esters 1.
1H- and 13C-NMR spectra confirmed the structure of the esters 1 and
thioethers 5. The two methylene groups always gave clear triplets in all
spectra recorded. While the correct signals for the protons in the amine
moiety of the dithiocarbamic group were identified in the aliphatic re-
1
gion of the H-NMR spectra for compounds 1, no peak was noticed in

2484
G. Roman et al.
this region of the 1H-NMR spectra of thioethers 5. The accurate number
of signals in the 13C-NMR spectra of substances 1 and 5 were discrimi-
nated for all carbon atoms. The signal at about 197 ppm offered evidence
for the presence of a new carbon atom from the dithiocarbamate moiety
in the structure of esters 1, whereas this signal was absent in the case
of thioethers 5. Both types of compounds presented a peak above 200
ppm corresponding to the carbon atom of the carbonyl group.
EXPERIMENTAL
Melting points were determined on a Boe¨tius hot-stage microscope and
are uncorrected. IR spectra were taken on a Specord M80 apparatus
1
in KBr pellets. H- and 13C-NMR spectra were recorded on a Varian
INOVA 300 instrument in CDCl3. All chemical shifts are reported in
ppm downfield from tetramethylsilane; the coupling constants (J) are
given in Hz.
3-Dimethylamino-1-(2-hydroxyphenyl)propan-1-one hydrochloride
3a11 and 3-dimethylamino-1-(2-hydroxy-5-methylphenyl)propan-1-one
hydrochloride 3b16 were prepared as described. Except for the com-
mercially available sodium N,N-diethyldithiocarbamate trihydrate 4d
(UCB-Belgia), all other dithiocarbamic acid salts 4 were generally pre-
pared from the corresponding amine and CS2 in the presence of a
base. Dithiocarbamic acid salts derived from pyrrolidine, piperidine
and morpholine 4a–c were all synthesized in the same manner,17
the base used in each of these three cases being the cyclic amine it-
self. Ammonium N-phenyldithiocarbamate 4e and ammonium N-(2-
methylphenyl)dithiocarbamate 4f were obtained through the same
known procedure,18 by reacting CS2 with aniline and ortho-toluidine
respectively in the presence of ammonium hydroxide. Another litera-
ture method19 was applied for the synthesis of triethylammonium N-
(2-pyridy)dithiocarbamate 4g, when the base employed was triethy-
lamine. All amines used in these syntheses, CS2 and all other required
reagents were commercially available products and were used without
prior purification.
Synthesis of Dithiocarbamic Acid Esters 1 Through
Amine Moiety Replacement---General Procedure
Mannich base hydrochloride 3 (5 mmol) was dissolved in water (20 mL)
and the resulting solution was added to the solution of the N,N-
dialkyldithiocarbamic acid salt 4a–d (5 mmol) in water (20 mL) with
good stirring. The esters 1 immediately separated as an emulsion that

Synthesis and Reactivity of Mannich Bases
2485
soon turned into a solid product. After being stirred for 3–4 h, the re-
action mixture was left at room temperature overnight. The dithio-
carbamic acid esters were filtered, washed with plenty of water and
recrystallized from the appropriate solvent.
S-(3-(2-Hydroxyphenyl)-3-oxopropyl)
Pyrrolidine-1-carbodithioate 1a
Yield 0.52 g (35%), m.p. 115–116◦C (ethanol). IR (KBr, cm−1): 1170,
1290, 1445 and 1495 ( S (C S) N< group); 1640 (νC O). 1H-NMR
(CDCl3, δ): 1.96–2.10 (m, 4H, CH2CH2 ); 3.56 (t, 2H, J = 6.6 Hz,
COCH2 ); 3.72 (t, 2H, J = 6.6 Hz, CH2S ); 3.64 and 3.94 (t, 2H,
J = 6.5 Hz, N(CH2 )); 6.88–6.93 (m, 1H); 6.98 (d, IH, J = 8.4 Hz);
1,2
7.45–7.50 (m, 1H); 7.81 (dd, 1H, J = 8 Hz, J = 1.3 Hz); 12.16 (s, 1H,
1,2
1,3
Ar OH). 13C-NMR (CDCl3, δ): 24.48 and 26.25 ( CH2CH2 ); 30.13
( CH2S ); 38.58 ( COCH2 ); 50.86 and 55.27 ( N(CH2 )2); 118.06,
118.64, 119.24, 130.29, 136.72, 162.34 (aromatic carbon atoms); 197.08
(>C S); 204.32 (>C O). Anal. calcd. for C14H17NO2S2 (295): C 56.92,
H 5.80, N 4.74; found C 57.06, H 5.97, N 4.59.
S-(3-(2-Hydroxy-5-methylphenyl)-3-oxopropyl)
Pyrrolidine-1-Carbodithioate 1b
Yield 0.82 g (53%). m.p. 131–132◦C (ethanol). IR (KBr, cm−1): 1170,
1290, 1445 and 1490 ( S (C S) N< group); 1645 (νC O). 1H-NMR
(CDCl3, δ): 1.98–2.08 (m, 4H, CH2CH2 ); 2.30 (s, 3H, Ar CH3); 3.54
(t, 2H, J = 6.6 Hz, COCH2 ); 3.71 (t, 2H, J = 6.6 Hz, −CH2S ); 3.64
and 3.94 (t, 2H, J = 6.5 Hz, N(CH2 )2); 6.88 (d, 1H, J = 8.5 Hz); 7.28
(dd, 1H, J1,2 = 8.5 Hz, J1,3 = 0.7 Hz); 7.6 (bs, 1H); 12.02 (s, 1H, Ar OH).
13C-NMR (CDCl3, δ): 20.67 (Ar CH3); 24.47 and 26.24 ( CH2CH2 );
30.18 ( CH2S ); 38.63 ( COCH2 ); 50.85 and 55.27 ( N(CH2 )2);
118.35, 118.86, 128.28, 129.98, 137.76, 160.41 (aromatic carbon atoms);
196.88 (>C S); 203.94 (>C O). Anal. calcd. for C15H19NO2S2 (309): C
58.22, H 6.19, N 4.53; found C 58.03, H 6.27, N 4.62.
S-(3-(2-Hydroxyphenyl)-3-oxopropyl)
Piperidine-1-carbodithioate 1c
Yield 0.37 g (24%), m.p. 103–104◦C (ethanol). IR (KBr, cm−1): 1165,
1250, 1450 and 1495 ( S (C S) N< group); 1650 (νC O). 1H-NMR
(CDCl3, δ): 1.63 (bs, 6H, CH2CH2CH2 ); 3.49 (t, 2H, J = 6.4 Hz,
COCH2 ); 3.65 (t, 2H, J = 6.6 Hz, CH2S ); 3.81 and 4.22 (bs,
2H + 2H, N(CH2 )2); 6.81–6.86 (m, 1H); 6.91 (d, 1H, J = 8.4 Hz);
1,2
7.38–7.43 (m, 1H); 7.73 (dd, 1H, J = 8 Hz, J = 1.3 Hz); 12.09 (s, 1H,
1,2
1,3
Ar OH). 13C-NMR (CDCl3, δ): 24.03, 25.27, 25.73 ( CH2CH2CH2 );
30.37 ( CH2S ); 38.15 ( COCH2 ); 51.13 and 52.76 ( N(CH2 )2);

2486
G. Roman et al.
118.17, 118.83, 119.07, 129.90, 136.28, 162.05 (aromatic carbon atoms);
196.73 (>C S); 204.30 (>C O). Anal. calcd. for C15H19NO2S2 (309): C
58.22, H 6.19, N 4.53; found C 58.37, H 6.02, N 4.62.
S-(3-(2-Hydroxy-5-methylphenyl)-3-oxopropyl)
Piperidine-1-carbodithioate 1d
Yield 0.53 g (33%), m.p. 135–136◦C (ethanol). IR (KBr, cm−1): 1180,
1250, 1445 and 1495 ( S (C S) N< group); 1650 (νC O). 1H-NMR
(CDCl3, δ): 1.71 (bs, 6H, CH2CH2CH2 ); 2.30 (s, 3H, Ar CH3); 3.54
(t, 2H, J = 6.6 Hz, COCH2 ); 3.72 (t, 2H, J = 6.6 Hz, CH2S );
3.88 and 4.31 (bs, 2H + 2H, N(CH2 )2); 6.89 (d, 1H, J = 8.5 Hz);
1,2
7.29 (dd, 1H, J = 8.5 Hz, J = 0.7 Hz); 7.60 (bs, 1H); 12.04 (s,
1,2
1,3
1H, Ar OH). 13C-NMR (CDCl3, δ): 20.69 (Ar CH3); 24.44, 25.81 and
26.21 ( CH2CH2CH2 ); 30.80 ( CH2S ); 38.64 ( COCH2 ); 51.49 and
53.04 ( N(CH2 )2); 118.34, 118.92, 128.24, 130.0, 137.75, 160.38 (aro-
matic carbon atoms); 196.46 (>C S); 204.53 (>C O). Anal. calcd. for
C16H21NO2S2 (323): C 59.41, H 6.54, N 4.33; found C 59.23, H 6.37, N
4.42.
S-(3-(2-Hydroxyphenyl)-3-oxopropyl) Morpholine-
4-carbodithioate 1e
Yield 0.36 g (23%), m.p. 125–126◦C (ethanol). IR (KBr, cm−1): 1145,
1285, 1430 and 1500 ( S (C S) N< group); 1650 (νC O). 1H-NMR
(CDCl3, δ): 3.54 (t, 2H, J = 6.5 Hz, COCH2 ); 3.73 (t, 2H, J = 6.6
Hz, CH2S ); 3.75 (bs, 4H, N(CH2 )2); 3.91 and 4.32 (bs, 2H + 2H,
( CH2)O); 6.86–6.92 (m, 1H); 6.96 (d, 1H, J = 8 Hz); 7.43–7.49 (m,
1,2
1H); 7.77 (d, 1H, J = 8 Hz); 12.10 (s, 1H, Ar OH). 13C-NMR (CDCl3,
1,2
δ): 30.47 ( CH2S ); 38.17 ( COCH2 ); 50.21 and 51.35 ( N(CH2 )2);
66.31 ( CH2OCH2 ); 118.33; 119.01; 119.24; 130.06; 136.42; 162.23
(aromatic carbon atoms); 196.91 (>C S); 204.44 (>C O). Anal. calcd.
for C14H17NO3S2 (311): C 53.99, H 5.50, N 4.50; found C 53.87, H 5.57,
N 4.60.
S-(3-(2-Hydroxy-5-methylphenyl)-3-oxopropyl)
Morpholine-4-carbodithioate 1f
Yield 0.63 g (39%), m.p. 155–156◦C (ethanol). IR (KBr, cm−1): 1130,
1280, 1430 and 1500 ( S (C S) N< group); 1650 (νC O). 1H-NMR
(CDCl3, δ): 2.30 (s, 3H, Ar CH3); 3.54 (t, 2H, J = 6.5 Hz, COCH2 );
3.74 (t, 2H, J = 6.6 Hz, CH2S ); 3.75 (bs, 4H, N(CH2 )2); 3.93 and
4.34 (bs, 2H+2H, ( CH2)O); 6.88 (d, 1H, J = 8.5 Hz); 7.29 (dd, 1H,
1,2
J
= 8.5 Hz, J = 0.8 Hz); 7.56 (bs, 1H); 11.94 (s, 1H, Ar OH). 13C-
1,2
1,3
NMR (CDCl3, δ): 20.65 (Ar CH3); 30.59 ( CH2S ); 38.31 ( COCH2 );
50.29 and 51.41 ( N(CH2 )2); 66.38 ( CH2OCH2 ); 117.76, 119.02,

Synthesis and Reactivity of Mannich Bases
2487
128.76, 130.43, 137.77, 160.38 (aromatic carbon atoms); 197.35 (>C S);
204.17 (>C O). Anal. calcd. for C15H19NO3S2 (325): C 55.36 H 5.88, N
4.30; found C 55.57, H 5.67, N 4.40.
S-(3-(2-Hydroxyphenyl)-3-oxopropyl)
N,N-Diethyldithiocarbamate 1g
Yield 0.82 g (55%), m.p. 81–82◦C (ethanol). IR (KBr, cm−1): 1210,
1270, 1445 and 1490 ( S (C S) N< group); 1645 (νC O). 1H-NMR
(CDCl3, δ): 1.28 (t, 6H, J = 7.1 Hz, CH2CH3); 3.55 (t, 2H, J = 6.6 Hz,
COCH2 ); 3.72 (t, 2H, J = 6.6 Hz, CH2S ); 4.03 (q, 4H, J = 7.1 Hz,
N(CH2 )2; 6.87-6.92 (m, 1H); 6.99 (d, 1H, J = 8.4 Hz); 7.44-7.50 (m,
1,2
1H); 7.81 (dd, 1H, J = 8 Hz, J = 1.4 Hz); 12.13 (s, 1H, Ar OH). 13C-
1,2
1,3
NMR (CDCl3, δ): 11.77 and 12.61 ( CH2CH3); 30.75 ( CH2S ); 38.48
( COCH2 ); 46.94 and 49.75 ( CH2CH3); ); 118.60, 119.21, 119.63,
130.30, 136.68, 162.46 (aromatic carbon atoms); 196.61 (>C S); 204.72
(>C O). ). Anal. calcd. for C14H19NO2S2 (297): C 56.53, H 6.44, N 4.71;
found C 56.69, H 6.36, N 4.61.
S-(3-(2-Hydroxy-5-methylphenyl)-3-oxopropyl)
N,N-Diethyldithiocarbamate 1h
Yield 0.71 g (46%), m.p. 105–106◦C (ethanol). IR (KBr, cm−1): 1215,
1280, 1425 and 1500 ( S (C S) N< group); 1650 (νC O). 1H-NMR
(CDCl3, δ): 1.28 (t, 6H, J = 7.1 Hz, CH2CH3); 2.31 (s, 3H, Ar CH3);
3.53 (t, 2H, J = 6.6 Hz, COCH2 ); 3.71 (t, 2H, J = 6.6 Hz, CH2S );
4.06 (q, 4H, J = 7.1 Hz, N(CH2 )2; 6.89 (d, 1H, J = 8.5 Hz); 7.29 (dd,
1,2
1H, J = 8.5 Hz, J = 0.9 Hz); 7.61 (bs, 1H); 12.08 (s, 1H, Ar OH). 13C-
1,2
1,3
NMR(CDCl3, δ): 11.80 and 12.62 ( CH2CH3); 20.69 (Ar CH3); 30.83
( CH2S ); 38.59 ( COCH2 ); 46.96 and 49.78 ( CH2CH3); 118.36,
118.84, 128.36, 130.03, 137.76, 160.39 (aromatic carbon atoms); 196.22
(>C S); 204.55 (>C O). Anal. calcd. for C15H21NO2S2 (311): C 57.84,
H 6.80, N 4.50; found C 58.03, H 6.61, N 4.37.
Thioethers 5 from Mannich Bases Derived from
ortho-Hydroxyacetophenones and N-Aryldithiocarbamic
Acid Salts 4e–g
Mannich base hydrochloride 3 (5 mmol) was dissolved in wa-
ter (20 mL) and the resulting solution was added to the so-
lution of ammonium N-phenyldithiocarbamate 4e (or ammonium
N-(2-methylphenyl)dithiocarbamate 4f, or triethylammonium N-(2-
pyridyl)dithiocarbamate 4g) (5 mmol) in water (20 mL) with good stir-
ring. The solid white thioethers separated immediately from the intitial
emulsion. After being stirred for 3–4 h, the reaction mixture was left

2488
G. Roman et al.
at room temperature overnight. The thioethers were filtered, washed
with plenty of water and recrystallized from the appropriate solvent.
1-(2-Hydroxyphenyl)-3-[3-(2-hydroxyphenyl)-3-
oxopropylthio]propan-1-one 5a
Yield 36–44%, m.p. 107–108◦C (ethanol). IR (KBr, cm−1): 1650 (νC
)
O
1H-NMR (CDCl3, δ): 2.96 (t, 4H, J = 7.2 Hz, CH2S ); 3.31 (t, 4H,
J = 7.2 Hz, COCH2 ); 6.86–6.91 (m, 2H); 6.96 (d, 2H, J = 8.3 Hz);
1,2
7.42–7.48 (m, 2H); 7.72 (dd, 2H, J = 8.1 Hz, J = 1.1 Hz); 12,10 (s,
1,2
1,3
2H, Ar OH). 13C-NMR (CDCl3, δ): 26.40 ( CH2S ); 38.39 ( COCH2 );
116.52, 119.00, 119.07, 129.67, 136.53, 162.31 (aromatic carbon atoms);
204.07 (>C O). Anal. calcd. for C18H18O4S (330): C 65.43, H 5.49; found
C 65.23, H 5.59.
1-(2-Hydroxy-5-methylphenyl)-3-[3-(2-hydroxy-5-
methylphenyl)-3-oxopropylthio]propan-1-one 5b
Yield 37–54%, m.p. 109–110◦C (ethanol). IR (KBr, cm−1): 1650 (νC O).
1H-NMR (CDCl3, δ): 2.27 (s, 6H, Ar CH3); 2.94 (t, 4H, J = 7.2 Hz,
CH2S ); 3.29 (t, 4H, J = 7.2 Hz, COCH2 ); 6.84 (d, 2H, J
=
1,2
8.4 Hz); 7.25 (d, 2H, J = 8.4 Hz); 7.48 (s, 2H); 11.91 (s, 2H,
1,2
Ar OH). 13C-NMR (CDCl3, δ): 20.48 (Ar CH3); 26.41 ( CH2S ); 38.40
( COCH2 ); 118.29, 118.75, 128.14, 129.36, 137.62, 160.27 (aromatic
carbon atoms); 203.96 (>C O). Anal. calcd. for C20H22O4S (358): C
67.01, H 6.19; found C 66.81, H 6.27.
Insertion of CS2 at the C N Bond in Mannich Bases Derived
from ortho-Hydroxyacetophenones
Mannich base hydrochloride
3
(5 mmol) and sodium N,N-
diethyldithiocarbamate trihydrate 4d (1.125 g, 5 mmol) were refluxed
for 1 h in 12 mL 1:1 (v/v) ethanol-water mixture. The reaction mixture
was cooled to room temperature and set aside. The clear supernatant
was removed and the remaining oily product was stirred with a little
cold ethanol until crystallization occurred. The solid was filtered off
and recrystallized from the appropriate solvent to give pure esters 1i
and 1j.
S-(3-(2-Hydroxyphenyl)-3-oxopropyl)
N,N-Dimethyldithiocarbamate 1i
Yield 0.16 g (12%), m.p. 131–132◦C (ethanol). IR (KBr, cm−1): 1155,
1285, 1380 and 1495 ( S (C S) N< group); 1650 (νC O). 1H-NMR
(CDCl3, δ): 3.36 and 3.56 (bs, 3H + 3H, N(CH3)2); 3.55 (t, 2H, J = 6.4
Hz, COCH2 ); 3.70 (t, 2H, J = 6.6 Hz, CH2S ); 6.87-6.92 (m, 1H);

Synthesis and Reactivity of Mannich Bases
2489
6.98 (d, 1H, J = 8.4 Hz); 7.44-7.50 (m, 1H); 7.79 (dd, 1H, J
=
1,2
1,2
8 Hz, J = 1.5 Hz); 12.10 (s, 1H, Ar OH). 13C-NMR (CDCl3, δ): 31.14
1,3
( CH2S ); 38.32 ( COCH2 ); 41.69 and 45.58 ( N(CH3)2); 118.61,
119.22, 119.64, 130.23, 136.70, 162.46 (aromatic carbon atoms); 196.89
(>C S); 204.57 (>C O). Anal. calcd. for C12H15NO2S2 (269); C 53.50,
H 5.61, N 5.20; found C 53.54, H 5.43, N 5.27.
S-(3-(2-Hydroxy-5-methylphenyl)-3-oxoprophyl)
N,N-Dimethyldithiocarbamate 1j
Yield 0.47 g (30%), m.p. 150–151◦C (acetone). IR (KBr, cm−1):
1
1180, 1290, 1380 and 1500 ( S (C S) N< group); 1650 (νC O). H-
NMR (CDCl3, δ): 2.24 (s, 3H, Ar CH3); 3.30 and 3.50 (bs, 3H +
3H, N(CH3)2); 3.46 (t, 2H, J = 6.5 Hz, COCH2 ); 3.63 (t, 2H, J =
6.6 Hz, CH2S ); 6.82 (d, 1H, J = 8.5 Hz); 7.22 (dd, 1H, J = 8.4 Hz,
1,2
1,2
J
= 1.9 Hz); 7.52 (s, 1H); 11.90 (s, 1H, Ar OH). 13C-NMR (CDCl3,
1,3
δ); 20.89 (Ar CH3); 31.44 ( CH2S ); 38.62 ( COCH2 ); 41.91 and
45.80 ( N(CH3)2); 118.56, 119.30, 128.57, 130.16, 137.98, 160.59 (aro-
matic carbon atoms); 197.17 (>C S); 204.63 (>C O). Anal. calcd. for
C13H17NO2S2 (283): C 55.09, H 6.05, N 4.94; found C 54.94, H 6.13,
N 4.87.
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