Hydrochlorination of 2,3-acetylenic acids with thionyl chloride in dimethylformamide

Article abstract of DOI:10.1081/SCC-120012990

The reaction of 2,3-acetylenic acids (1a-d) with thionyl chloride in DMF under mild conditions gave E,Z-3-chloro-2-alkenoic acids (2a-d) or esters (3a-d) depending on treating the reaction mixture with either water or alcohols.

Full text of DOI:10.1081/SCC-120012990

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HYDROCHLORINATION OF 2,3-ACETYLENIC ACIDS WITH
THIONYL CHLORIDE IN DIMETHYLFORMAMIDE
a
a
a
a
Neudo A. Urdaneta , Julio C. Herrera , José Salazar & Simón E. López
a
Departamento de Química , Universidad Simón Bolívar , Apartado 89000, Caracas,
Venezuela, 1080A
Published online: 16 Aug 2006.
To cite this article: Neudo A. Urdaneta , Julio C. Herrera , José Salazar & Simón E. López (2002) HYDROCHLORINATION OF
,3-ACETYLENIC ACIDS WITH THIONYL CHLORIDE IN DIMETHYLFORMAMIDE, Synthetic Communications: An International Journal
2
for Rapid Communication of Synthetic Organic Chemistry, 32:19, 3003-3009, DOI: 10.1081/SCC-120012990
To link to this article: http://dx.doi.org/10.1081/SCC-120012990
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SYNTHETIC COMMUNICATIONS
Vol. 32, No. 19, pp. 3003–3009, 2002
HYDROCHLORINATION OF
,3-ACETYLENIC ACIDS WITH THIONYL
CHLORIDE IN DIMETHYLFORMAMIDE
2
Neudo A. Urdaneta,* Julio C. Herrera,
Jose Salazar, and Simon E. Lopez
´
´
´
Departamento de Quımica, Universidad Simon Bolıvar,
´ ´ ´
Apartado 89000, Caracas 1080A, Venezuela
ABSTRACT
The reaction of 2,3-acetylenic acids (1a–d) with thionyl
chloride in DMF under mild conditions gave E,Z-3-chloro-
2-alkenoic acids (2a–d) or esters (3a–d) depending on treating
the reaction mixture with either water or alcohols.
Key Words: Hydrochlorination; Acetylenic acids; 3-Chloro-
2-propenoic acids; Thionyl chloride; Dimethylformamide
[
-Halo-2-alkenoic acids and their esters
1]
[2–4]
3
are valuable and versa-
tile intermediates in organic synthesis due to their high functionality (halo-
gen atom, carbon–carbon double bond and a carboxylic or ester group).
Preparation methods for these intermediates are based in the addition of
[
5–9]
[10–12]
[13,14]
hydrogen halides
acetic acid to a 2,3 acetylenic acid or ester.
and halides salts of lithium
or sodium
in
During the preparation of some ester analogs of 3-phenyl-2-propynoic
acid using thionyl chloride in dimethylformamide and the corresponding
*
Corresponding author. E-mail: urdanet@usb.ve
003
3
DOI: 10.1081/SCC-120012990
Copyright & 2002 by Marcel Dekker, Inc.
0039-7911 (Print); 1532-2432 (Online)
www.dekker.com

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3
004
URDANETA ET AL.
[
15]
alcohol,
3
we found that the only products were the unexpected E,Z-
-chloro-3-phenyl-2-propenoic esters. An extensive bibliography search
revealed the great versatility of thionyl chloride as a chlorinating agent,
specially in combination with DMF as catalyst, for the preparation of acid
[
16]
chlorides and other many applications
which include the so called
Villsmeier type reactions. However, we found a very limited number of
reports concerning to its use in the addition reactions to acetylenic
[17]
compounds.
The observed addition products were mainly the dichloro
[
18]
but not the monochlorinated compounds. In this work, we report a new
method (Sch. 1) for the hydrochlorination of 2,3-acetylenic acids, using thio-
nyl chloride in DMF as solvent, at room temperature in short times (45 min).
When the reaction mixture was treated with ice, the corresponding
E,Z-3-chloro-2-alkenoic acids (2a–d) were obtained (Table 1), whereas if
it was treated with an alcohol in pentane, the corresponding E,Z-
3-chloro-2-alkenoates (3a–d) were the products. In both cases the reactions
occurred with excellent yields.
The hydrogen chloride generated from the formation of the acid
chlorides, through a Villsmeier–Haack type SOCl –DMF complex, may
2
[
16,20]
account for the hydrochlorination of the triple bond.
When R ¼ Ph
(
the steric hindrance of the rigid phenyl ring.
2d, 3d) the cis isomer predominates. This stereospecificity may be due to
[
19,21]
Scheme 1.

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E,Z-3-CHLORO-2-ALKENOIC ACIDS
3005
Table 1. E,Z-3-Chloro-2-alkenoic Acids 2a–d and Their
Esters 3a–d Obtained According to the Sch.1
Acetylenic
Acid
3-Chloro-2-Alkenoic
Acids and Esters
Overall
a
Yield
E,Z
Ratio
b
1
1
1
1
1
1
1
1
a
a
b
b
c
c
d
d
2a
3a
2b
3b
2c
3c
2d
3d
75
88
80
60
87
80
90
85
90 : 10
80 : 20
75 : 25
75 : 25
60 : 40
60 : 40
30 : 70
40 : 60
a
Yield of isolated mixture after work up.
b
Calculated based on the NMR spectral data of the purified
mixture.
In conclusion, this work represents a new method for the hydro-
chlorination of 2,3-acetylenic acids, affording the corresponding E,Z-
3-chloro-2-alkenoic acids and their esters under mild conditions and short
reaction times. The ready availability of the employed reagents and the
simplicity of the procedure becomes it an affordable method in organic
synthesis.
EXPERIMENTAL
IR spectra were recorded on a Excalibur (Biorad) FT-IR spectro-
13
1
photometer. H NMR and C NMR were recorded on a Eclipse þ (JEOL)
400 MHzspectrometer. Mass spectra were obtained on a Series II-HP5890
Gas-Chromatograph (Hewlett Packard) with a HP5971A (Hewlett Packard)
Mass Detector. Elemental analyses were performed by Atlantic Microlab
Inc. (Norcross, GA, USA).
Generalprocedure for the preparation of E,Z-3-chloro-2-alkenoic acids
and esters. To a solution of acetylenic acid 1 (1 mmol) in dry DMF (1 mL)
was slowly added thionyl chloride (1.2 mmol) keeping the temperature
ꢀ
below 30 C. After stirring for 45 min, the excess of thionyl chloride was
removed under reduced pressure. The residue was poured on ice and the
resulting aqueous solution was extracted with ether. The organic layer was
then washed with water, dried with anhydrous Na SO , filtered and con-
2
4
centrated under vacuum to give a mixture of the corresponding alkenoic

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3
006
URDANETA ET AL.
acids (2a–d). In case of the esters (3a–d) a similar procedure as that for the
-chloro-2-alkenoic acids was followed. But after the removal of the thionyl
chloride, n-pentane was added (3 mL) and then the corresponding alcohol
4 mmol). Following a work-up as for the acids, an isolated mixture of the
3
(
corresponding esters was obtained with good purity and further purification
was not needed. The E, Z-acid mixtures were separated by column chroma-
tography on silicagel, with n-hexane and EtOAc as eluent (80 : 20). For the
E, Z-esters mixtures similar procedures were used, the eluent was n-hexane
[
10,11]
[6]
[6,13,22]
[11]
[23]
and EtOAc (97 : 3). All products 2a,
known except 2c, 3c and 3d.
2b, 2d
), 3a, 3b were
ꢀ
ꢀ
[10]
(
Z)-3-Chloropropenoic acid (2a): M.p. 59–60 C (Lit. 60–62.5 C).
1
H NMR (CDCl ): ꢀ 9.24 (bs, 1H), 7.49 (d, J ¼ 8.4 Hz, 1H), 6.23
3
þ.
(
d, J ¼ 8.4, 1H). MS m/z (%): M 106 (90), 89 (100), 71 (60), 61 (50),
4
5 (30).
(
ꢀ
ꢀ
[11]
E)-3-Chloropropenoic acid (2a): M.p. 80–81 C (Lit. 82–83 C).
H NMR (CDCl ): ꢀ 9.24 (bs, 1H), 7.52 (d, J ¼ 13 Hz, 1H), 6.26 (d,
1
3
þ.
J ¼ 13 Hz, 1H). MS m/z (%): M 106 (90), 89 (100), 71 (60), 61 (50), 45 (30).
ꢀ
ꢀ
[6] 1
(
Z)-3-Chloro-2-butenoic acid (2b): M.p. 58 C (Lit. 59 C).
H NMR
[
6] 1
(CDCl ): ꢀ 6.06 (s, 1H), 2.23 (s, 1H). Lit. H: ꢀ 6.09 (s, 1H ), 2.42 (s, 1H).
MS m/z (%): M 120 (100), 104 (20), 102 (40), 84 (80).
3
þ.
ꢀ
ꢀ
[6] 1
(
E)-3-Chloro-2-butenoic acid (2b): M.p. 92 C (Lit. 94 C).
[
H NMR
6] 1
(
MS m/z (%): M 120 (100), 104 (20), 102 (40), 84 (80).
CDCl ): ꢀ 6.10 (s, 1H ), 2.58 (s, 1H). Lit. H: ꢀ 6.10 (s, 1H), 2.62 (s, 1H).
3
þ.
ꢁ
1
(
Z)-3-Chloro-2-octenoic acid (2c): A pale yellow oil. IR neat ꢁ (cm ):
1
1
610 (C¼C), 1700 (C¼O). H NMR (CDCl ) ꢀ: 6.08 (s, 1H), 2.44–2.46
3
(
(
1
5
7
t, J ¼ 7.6 Hz, 2H), 1.61–1.64 (m, 2H), 1.29–1.33 (m, 4H), 0.87–0.89
1
3
t, J ¼ 6.12 Hz, 3H). C NMR ꢀ: 169.6, 160.9, 115.6, 41.6, 30.7, 26.9, 22.3,
þ.
3.9. MS m/z (%): 176 (5) M , 141 (39), 133 (49), 120 (30), 97 (39), 85 (81),
6 (100), 43 (21), 41 (60), 39 (29). Anal. Calcd. for C H O Cl: C, 54.40, H,
8
13
2
.42, Found: C, 54.32, H, 7.33.
E)-3-Chloro-2-octenoic acid (2c): A pale yelIow oil. R neat ꢁ (cm ):
ꢁ1
(
1
1
605 (C¼C), 1695 (C¼O). H NMR (CDCl ): ꢀ 6.04 (s, 1H), 2.94–2.97
3
(
(
1
t, J ¼ 7.6 Hz, 2H), 1.61–1.64 (m, 2H), 1.29–1.33 (m, 4H) 0.87–0.89
1
3
t, J ¼ 6.12 Hz, 3H). C NMR: ꢀ 169.6, 150.2, 118.4, 37.8, 30.7, 26.9, 22.3,
þ.
3.9. MS m/z (%): M 176 (5), 141 (34), 133 (49), 120 (30), 95 (62), 81 (16),
56 (100), 55 (32), 41 (69), 39 (28). Anal. Calcd. for C H O Cl: C, 54.40;
H, 7.42. Found: C, 54.32; H, 7.33.
8
13
2
ꢀ
(
33 C).
s,1H). Lit.
1
Z)-3-Chloro-3-phenyl-2-propenoic acid (2d): M.p. 134–135 C (Lit.
[6] 1
ꢀ
1
(
(
H NMR (CDCl ): ꢀ 10.2 (bs, 1H), 7.45–7.72 (m, 5H), 6.59
3
H: ꢀ 9.95 (bs, 1H), 7.45–7.86 (m, 1H), 6.65 (s, 1H ), 2.42
s, 1H). C NMR (CDCl ): ꢀ 169.46, 149.24, 137.10, 131.19, 128.78, 127.48,
[6,13] 1
3
3
þ.
1
15.54. MS m/z (%): M 182 (90), 89 (100), 71 (60), 61 (50), 45 (30).

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E,Z-3-CHLORO-2-ALKENOIC ACIDS
3007
ꢀ
(
42–143 C),
.38 (s,1H). Lit.
1
E)-3-Chloro-3-phenyl-2-propenoic acid (2d): M.p.141–142 C (Lit.
ꢀ
[6,13,22] 1
1
6
2
1
H NMR (CDCl ): ꢀ 10.2 (bs, 1H ), 7.45–7.72 (m, 5H),
H: ꢀ 9.95 (bs, 1H), 7.45–7.98 (m, 1H), 6.38 (s, 1H),
.42 (s, 1H). C NMR (CDCl ): ꢀ 169.46, 149.24, 137.10, 130.35, 128.62,
3
[13,22] 1
3
3
þ.
28.09, 119.054. MS m/z (%): M 182 (100), 165 (20), 137 (15), 102 (40), 77
(
20), 69 (20), 51 (20).
1
Allyl-(Z)-3-chloropropenoate (3a): A colorless oil. H NMR (CDCl ): ꢀ
3
6
.88 (d, J ¼ 8.36, 1H), 6.18 (d, J ¼ 8.5 Hz, 1H), 5.89–5.24 (m, 1H). 4.82
[
11] 1
(
d, J ¼ 5.5 Hz, 2H). Lit.
H: ꢀ 6.55(d, J ¼ 8.40, 1H), 6.40–5.00 (m, 4H),
4.60 (d, 2H).
1
Allyl-(E)-3-chloropropenoate (3a): A colorless oil. H NMR (CDCl ): ꢀ
3
7
5
1
8
.38 (d, J ¼ 13 Hz,, 1H), 6.25 (d, J ¼ 13.5 Hz, 1H), 6.10–6.81 (m, 1H).
1
3
.34–5.20 (m, 2H), 4.58–4.61 (d, J ¼ 5.6 Hz, 2H). C (CDCl ): ꢀ 163.79,
3
þ.
38.61, 131.73, 124.62, 118.73, 65.57. MS m/z (%): M 146 (5), 111 (20),
9 (100), 61 (20), 57 (15), 41 (20).
1
colorless oil H NMR
Methyl-(Z)-3-chloro-2-butenoate (3b):
A
[
23] 1
(
CDCl ): ꢀ 6.19 (s, 1H), 3.63 (s, 3H), 2.35 (s, 3H). Lit.
H: ꢀ 5.95
3
1
3
(
s, 1H), 3.68 (s, 3H ), 2.25 (s, 3H). C NMR: ꢀ 165.0, 145.0, 116.9,
þ
.
[23] 13
5
1
0.5, 25.3. Lit.
34 (100).
C: ꢀ 163.5, 145.7, 117.2, 50.7, 27.9. MS m/z (%): M
1
colorless oil. H NMR
Methyl-(E)-3-chloro-2-butenoate (3b):
A
[
23] 1
(
CDCl ): ꢀ 6.21 (s,1H) 3.62 (s, 3H), 2.66 (s, 3H). Lit.
H: ꢀ 6.01 (s, 3H),
3
1
3
3.67 (s, 3H), 2.58 (s, 3H). C: ꢀ. 164.5, 152.5, 119.2, 50.9, 23.5. MS m/z (%):
þ.
1
134 (100). H NMR data obtained for the methyl-(Z,E)-3-chloro-2-
M
butenoates, were also compared with the H NMR literature values of
their methyl-(Z,E)-3-bromo-2-butenoate analogues.
1
[
7]
ꢁ
1
Allyl-(Z)-3-chloro-2-octenoate (3c): A colorless oil. IR neat ꢁ (cm ):
1
1
620, 1650 (C¼C), 1730 (C¼O). H NMR (CDCl ): ꢀ 6.01 (s, 1H), 5.85–5.92
3
(
(
(
m, 1H), 5.22–5.34 (m, 2H), 4.59–4.61 (d, J ¼ 5.5 Hz, 2H), 2.27–2.31
t, J ¼ 7.6 Hz, 2H), 1.54–1.64 (m, 2H), 1.27–1.30 (m, 4H), 0.86–0.88
1
3
t, J ¼ 6.12 Hz, 3H). C NMR (CDCl ): ꢀ 163.6, 153.5, 131.4, 119.1,
3
þ.
1
15.8, 66.3, 30.9, 27.3, 18.7. MS m/z (%): M 216 (5), 141 (94), 133
(
Calcd. for C H O Cl: C, 60.98; H, 7.90. Found: C, 60.54; H, 8.09.
100), 120 (42), 97 (62), 85 (81), 56 (38), 43 (15), 41 (45), 39 (27). Anal.
1
2
17
2
ꢁ
1
Allyl-(E)-3-chloro-2-octenoate (3c): A colorless oil. IR neat (ꢁ cm ):
1
1
620, 1650 (C¼C), 1730 (C¼O). H NMR (CDCl ): ꢀ 6.01 (s, 1H), 5.85–5.92
3
(
(
(
m, 1H), 5.22–5.34 (m, 2H), 4.59–4.61 (d, J ¼ 5.5 Hz, 2H), 2.38–2.40
t, J ¼ 7.6 Hz, 2H), 1.54–1.64 (m, 2H), 1.27–1.30 (m, 4H), 0.86–0.88
1
3
t, J ¼ 6.12 Hz, 3H). C NMR: ꢀ 163.6, 153.5, 131.4, 119.1, 115.8, 66.3,
þ.
3
0.9, 27.3, 18.7. MS m/z (%): M 216 (6) 159 (40), 131 (16), 123 (32), 93
(45), 79 (20), 67 (29), 57 (26), 41 (100), 39 (40). Anal. Calcd. for C H O Cl:
12 17 2
C, 60.98; H, 7.90. Found: C, 60.54; H, 8.09.

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3
008
URDANETA ET AL.
Iso-propyl-(Z)-3-chloro-3-phenyl-2-propenoate (3d): A pale yellow oil.
H NMR (CDCl ): ꢀ 7.40–7.65 (m, 5H ), 6.51 (s, 1H), 5.11–5.19 (hept., 1H),
1
3
1
3
1
1
1
.29–1.33 (d, 3H). C (CDCl ): ꢀ 163.79, 145.76, 137.41, 130.62, 128.67,
27.91, 117.02, 68.25, 21.95. MS m/z (%): M 224 (30), 183 (50), 181 (100),
65 (80), 138 (60), 102 (60), 77 (20), 59 (15), 43 (30). Anal. Calcd. for
3
þ.
C H O Cl: C, 54.15; H, 5.83. Found: C, 54.23; H, 8.92.
1
2
13
2
Iso-propyl-(E)-3-Chloro-3-phenyl-2-propenoate (3d): A pale yellow oil.
H NMR (CDCl ): ꢀ 7.40–7.65 (m, 5H ), 6.31 (s, 1H), 4.89–4.92 (hept., 1H),
1
3
1
3
1
1
1
.07–1.09 (d, 3H). C (CDCl ): ꢀ 163.42, 145.76, 136.88, 129.86, 128.51,
20.65, 117.02, 68.25, 21.58. MS m/z (%): M 224 (30), 183 (50), 181 (100),
65 (80), 138 (60), 102 (60), 77 (20), 59 (15), 43 (30). Anal. Calcd. for
3
þ.
C H O Cl: C, 54.15; H, 5.83. Found: C, 54.23; H, 8.92.
1
2
13
2
ACKNOWLEDGMENTS
The authors would like to thank NMR Laboratory at Chemistry
Department-Universidad Simon Bolıvar (Proyect BID-CONICIT QF-13)
and The National NMR Laboratory.
´
´
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Received in the USA September 14, 2001

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