Combining AlCl3·6H2O and an ionic liquid to prepare chlorohydrin esters from glycerol

Article abstract of DOI:10.1016/j.tetlet.2009.03.183

We describe here the first example in which glycerol has been transformed into chlorohydrin esters using an ionic liquid and hydrated aluminium chloride. The method avoids using Crown-18 ether, which was needed to obtain a similar yield when KCl was used.

Full text of DOI:10.1016/j.tetlet.2009.03.183

Tetrahedron Letters 50 (2009) 2828–2830
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Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Combining AlCl3Á6H2O and an ionic liquid to prepare chlorohydrin esters
from glycerol
Gemma Villorbina a, Albert Tomàs a, Marc Escribà a, Mireia Oromí-Farrús a, Jordi Eras a, Mercè Balcells a,b
,
Ramon Canela a,b,
*
a Department of Chemistry, Lleida University, Alcalde Rovira Roure 191, 25198 Lleida, Spain
b Centre UdL-IRTA, Alcalde Rovira Roure 191, 25198 Lleida, Spain
a r t i c l e i n f o
a b s t r a c t
Article history:
We describe here the first example in which glycerol has been transformed into chlorohydrin esters using
an ionic liquid and hydrated aluminium chloride. The method avoids using Crown-18 ether, which was
needed to obtain a similar yield when KCl was used. Alkyl and aryl acids can be used, although yields are
very dependent on the carboxylic acid used.
Received 22 December 2008
Revised 21 March 2009
Accepted 27 March 2009
Available online 1 April 2009
Ó 2009 Elsevier Ltd. All rights reserved.
On the occasion of Professor Josep Font’s
retirement
Keywords:
[BMIM][PF6]
Chlorohydrin esters
Glycerol
Hydrated aluminium chloride
Ionic liquid
Substitution
Glycerol is considered a low-cost, renewable feedstock that is a
co-product of the biodiesel process.1 Recently, new procedures
have been patented to convert this compound to a mixture of chlo-
rohydrin esters, commercial compounds with wide applications.2
We have already developed a direct methodology to prepare
chlorohydrin esters from polyols. The method consists of a one-
pot esterification–chlorination reaction, in which chlorotrimethyl-
silane acts as a solvent and reagent. Using this methodology,
dichloropropyl esters can be obtained by an esterification–substi-
tution reaction from 4-hydroxymethyl-2,2-dimethyl-1,3-dioxolane
(solketal), a monoketal from glycerol.3 Dichloropropyl palmitate
could be also obtained in low yields from glycerol and hydrochloric
acid.4 To avoid the use of chlorotrimethylsilane, we have devel-
oped a new friendly one-pot halohydrin ester synthesis using
potassium halides (KX) as the halogen source in ionic liquids
([BMIM][PF6]) in the presence of Crown-18 ether.5 Using this
methodology, several diols and carboxylic acids were transformed
to the corresponding halohydrin esters.
acid to give the corresponding chlorohydrin ester in 48 h with
[BMIM][PF6] as a solvent and AlCl3Á6H2O as a source of chlorine.6
The corresponding 1,3-dichloro-2-propyl ester 3 (Fig. 1) is the
main regioisomer. When palmitic acid is chosen as a model re-
agent, it is observed that yields can be maintained by using
AlCl3Á6H2O instead of KCl7 (entry a), avoiding the use of crown
ether as was proposed in our previous work (Table 1).
To the best of our knowledge, this reaction represents the first
example of dichlorohydrin ester synthesis from glycerol using an
ionic liquid and metal halide as chloride source. Hydrated alumin-
ium chloride is much easier to handle than the corresponding
anhydrous AlCl3 and Friedel–Craft-like reactions are avoided.
The importance of these results particularly relates to: (i) the
transformation of a renewable material to valuable compounds,
OH OH
Cl
Cl
O
Cl
O
O
AlCl3·6H2O
[BMIM][PF6]
As a continuation of our work, we report here that glycerol
undergoes an esterification–substitution reaction with a carboxylic
R
+
R
+
R
O
OH
O
4
Cl
OH
1
3
2
R = alkyl or aryl
* Corresponding author. Tel.: +34 973 702843; fax: +34 973 238264.
E-mail address: canela@quimica.udl.cat (R. Canela).
Figure 1. Preparation of dichloropropyl esters from glycerol and a carboxylic acid.
0040-4039/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2009.03.183

G. Villorbina et al. / Tetrahedron Letters 50 (2009) 2828–2830
2829
Table 1
Acids with shorter chain lengths showed lower yields. For aromatic
and heteroaromatic acids, yields range from high (benzoic and 3-
nitrobenzoic acids) to low (salicylic, cinnamic and 1-naphthoic
acids) (Table 1). The reaction is compatible with C@C bonds,
aromatic amino and hydroxyl groups. Only picolinic acid (2q) did
not give the desired compounds in the described conditions.
These results are similar to those obtained in our previous work
when several diols were assayed.5 The fact that these reactions in
ionic liquids are very sensitive to the chemical structure of the re-
agents can be used again to explain these results.12 Consequently,
large aliphatic acids (oleic, palmitic and pentadecanoic acids) and
some small aromatic acids will be the best acids for carrying out
this reaction in [BMIM][PF6]. Moreover, the recovery of the result-
ing esters from the reaction mixture with solvents such as hexane
seems more difficult when aromatic acids are used (Table 1). The
addition of water at the end of the reaction, followed by extraction
with ethyl acetate seems to overcome this second fact.
In conclusion, we have described the first example in which
glycerol has been transformed to chlorohydrin esters using an ionic
liquid and hydrated aluminium chloride. The described method
avoids using Crown-18 ether needed to obtain satisfactory yields
when KCl is used. Alkyl and aryl acids can be used, although yields
are very dependent on the carboxylic acid used. Aminoaromatic
acids seem to be compatible with the reaction conditions used.
Dichoropropyl esters 3a–p:4a–p produced from glycerol and carboxylic acid in
[BMIM][PF6]
Entry
R
Conditions
Ratio
Yieldb
(%)
3:4a
a
CH3(CH2)14
CH3(CH2)14
KCl (5 mequiv), 18-Crown 94:6
etherc
83
a
b
c
d
e
f
AlCl3Á6H2O (2 mequiv)c
93:7
95:5
95:5
96:4
70:30
68:32
68:32
81:19
81:19
78:22
78:22
68:32
68:32
86:14
86:14
83:13
83:13
—
88:12
95:5
95:5
—
55:45
72:28
72:28
75:25
75:25
—
80
73
76
56
28
8
48
13
50
25
87
9
CH3(CH2)4CH@CH(CH2)10 AlCl3Á6H2O (2 mequiv)c
CH3(CH2)13
CH3(CH2)10
CH3(CH2)6
2-Furoyl
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)d
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)d
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)d
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)d
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)d
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)d
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)d
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)d
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)d
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)d
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)d
AlCl3Á6H2O (2 mequiv)c
AlCl3Á6H2O (2 mequiv)d
f
2-Furoyl
g
g
h
h
i
i
j
j
2-Thiophencarboxoyl
2-Thiophencarboxoyl
Benzoyl
Benzoyl
Cinnamyl
Cinnamyl
Salicyl
Salicyl
2-Chlorobenzoyl
2-Chlorobenzoyl
3-Aminobenzoyl
3-Aminobenzoyl
3-Nitrobenzoyl
3-Nitrobenzoyl
3,5-Dinitrobenzoyl
3,5-Dinitrobenzoyl
1-Naphthoyl
1-Naphthoyl
2-Naphthoyl
2-Naphthoyl
Picolyl
36
6
21
19
64
k
k
l
e
—
l
41e
9
m
m
n
n
o
o
p
p
q
q
88
—
56
16
24
30
62
Acknowledgement
This work was supported by a Grant-in-Aid from the Secretaría
de Estado de Política Científica y Tecnológica of the Spanish Minis-
try of Education and Culture (contract Grant No.: CTQ2006-07451/
PPQ).
e
—
—
e
Picolyl
—
Calculated by 1H NMR considering signals at d = 5.19 ppm for
3 and
a
d = 4.22 ppm for 4.
References and notes
b
Yield calculated by 1H NMR using 1,4-dichlorobenzene for aliphatic acids and
1,4-dioxane for aromatic and heteroaromatic acids.
1. (a) Zhou, C.-H. C.; Beltramini, J. N.; Fana, Y.-X.; Lu, G. Q. M. Chem. Soc. Rev. 2008,
37, 527–549; (b) Zheng, Y.; Chen, X.; Shen, Y. Chem. Rev. 2008, 108, 5253–5277;
(c) Jérôme, F.; Pouilloux, Y.; Barrault, J. ChemSusChem 2008, 1, 586–615; (d)
Pagliaro, M.; Ciriminna, R.; Kimura, H.; Rossi, M.; Della Pina, C. Angew. Chem.,
Int. Ed. 2007, 46, 4434–4440.
c
Crude reaction mixture was extracted with hexane.
Crude reaction mixture was dissolved in water and extracted with ethyl acetate.
d
e
After careful neutralization with solid sodium bicarbonate.
2. (a) Hook, B. D.; Briggs, J.; Campbell, R. M.; Kruper, W. J.; Schreck, D. J.; Varjian,
R. D.; Hippler, J. G. US20080015370, 2008.; (b) Kruper, W. J.; Arrowood, T.; Bell,
B. M.; Briggs, J.; Campbell, R. M.; Hook, B. D.; Nguyen, A.; Theriault, C.; Fitschen,
R. US 20080015369, 2008.; (c) Schreck, D. J.; Kruper, W. J., Jr.; Varjian, R. D.;
Jones, M. E.; Campbell, R. M.; Kearns, K.; Hook, B. D.; Briggs, J. R.; Hippler, J. G.
WO 2006020234, 2006.
3. Eras, J.; Méndez, J. J.; Balcells, M.; Canela, R. J. Org. Chem. 2002, 67, 8631–9634.
4. Eras, J.; Balcells, M.; Canela, R. Afinidad 2007, 64, 203–206.
5. Oromí-Farrús, M.; Eras, J.; Villorbina, G.; Torres, M.; Llopis-Mestre, V.; Welton,
T.; Canela, R. Anal. Sci. 2008, 24, 1341–1345.
(ii) the use of a handy chloride salt as chloride source and (iii) the
use of an ionic liquid (IL) as solvent.
Table 1 shows the different regioisomeric ratios obtained
depending on the carboxylic acid used. Nevertheless, regioisomer
3 is always the main compound obtained. Kinetic control is pro-
posed to explain the predominance of this regioisomer. This
hypothesis is in agreement with several similar reactions.8 The ra-
tio dependence upon the carboxylic acid used could be explained
considering the charge density at the carbon of the carboxylic
group.9 Nevertheless, 3-nitrobenzoic acid and oleic acid gave the
highest 3:4 ratio whereas 3,5-nitrobenzoic acid gave the lowest
3:4 ratio. Ionic liquids can produce different electrostatic environ-
ments, which can significantly affect a given reaction. Furthermore,
6. Experimental procedure:
A mixture of carboxylic acid (1 mequiv), glycerol
(2 mequiv) and hydrated aluminium chloride (2 mequiv) and [BMIM][PF6]
(2.5 g) were stirred in a 10 mL reactor for 48 h at 100 °C. The crude reaction
mixture was extracted with hexane (3 Â 2 mL) while stirring in a circular
shaker placed into an oven for 30 min at 40 °C. Crude reaction mixtures from
aromatic and heteroaromatic acids were also dissolved in water and extracted
with ethyl acetate (3 Â 20 mL). The upper phase was recovered and dried over
anhydrous sodium sulfate. Organic solutions were filtered and evaporated to
dryness. Yields were determined using 1H NMR with either 1,4-
dichlorobenzene or 1,4-dioxane as internal standard (see Table 1).
ionic liquids are able to give p–p and p–cation interactions that in
1,3-Dichloro-2-propyl palmitate (3a): 1H NMR (CDCl3), d: 5.18 (quin, J = 5.2 Hz,
some cases may significantly affect the reactivity in these solvent
media.10 Bearing in mind the putative ionic intermediates present
in these processes,3 ions constituting ionic liquids could induce dif-
ferent effects depending on the starting carboxylic acid. Opposing
effects on the rate of reaction of the substrate have been described
for unimolecular substitution processes in presence of ionic liq-
uids. Addition of different amounts of ionic liquid to the reaction
mixture, favoured in different extents the reaction in terms of acti-
vation enthalpy whereas disfavoured it in terms of activation en-
tropy.11 These facts could explain that the regioisomeric ratios
were very sensitive to the chemical structure of the reagents.
Yields are also rather dependent on the carboxylic acid used. For
aliphatic acids, the highest yield was obtained for palmitic acid.
1H, O–CH), 3.73 (m, 4H, 2 CH2–Cl), 2.37 (t, J = 7 Hz, 2H, CH2 ( ) (C@O)), 1.65 (m,
a
2H, CH2
(C@O)), 1.26 (m, 24H, CH2), 0.88 (t, J = 7 Hz, 3H, CH3). 13C RMN
(b)
(CDCl3), d: 172.7 (C@O), 71.5 (O–CH), 42.5 (CH2–Cl), 34.1 (CH2
(C@O)), 31.9
(a)
(CH2–CH2–CH3), 29.7, 29.6, 29.5, 29.4, 29.3, 29.2, 29.0 (CH2), 24.8 (CH2
(C@O)), 22.7 (CH2-CH3), 14.1 (CH3).
(b)
1,3-Dichloro-2-propyl oleate (3b): 1H NMR (CDCl3), d: 5.35 m, 2H, CH@CH), 5.18
(quin, J = 5.1 Hz, 1H, O–CH), 3.74 (dd, J1 = 11.6 Hz, J2 = 2 Hz, 4H, 2 CH2–Cl), 2.36
(t, J = 7.4 Hz, 2H, CH2
(C@O)), 2.0 (m, 4H, CH2–CH@), 1.68 (m, 2H, CH2
(
a
)
(b)
(C@O)), 1.26 (m, 18H, CH2), 0.88 (t, J = 7.0 Hz, 3H, CH3). 13C RMN (CDCl3), d:
172.9 (C@O), 130.2, 129.9 (CH@CH), 71.7 (O–CH), 42.7 (CH2–Cl), 34.3 (CH2
(a)
(C@O)), 32.1 (CH2–CH2–CH3), 30.0, 29.9, 29.7, 29.5, 29.4, 29.3, (CH2), 26.7 (CH2–
CH@CH–CH2), 25.0 (CH2 (C@O)), 22.9 (CH2-CH3), 14.3 (CH3). HRMS (EI+)
(b)
calculated for C11H20O2Cl2: 392.2249. Found: 392.2247.
1,3-Dichloro-2-propyl pentadecanoate (3c): 1H NMR (CDCl3), d: 5.18 (quin,
J = 5.2 Hz, 1H, O–CH), 3.74 (dd, J1 = 5.4 Hz, J2 = 2 Hz, 4H, 2 CH2–Cl), 2.36 (t,
J = 7.4 Hz, 2H, CH2
(C@O)), 1.64 (m, 2H, CH2
(C@O)), 1.25 (m, 22H, CH2),
(
a)
(b)

2830
G. Villorbina et al. / Tetrahedron Letters 50 (2009) 2828–2830
0.87 (t, J = 6.9 Hz, 3H, CH3). 13C RMN (CDCl3), d: 173.0 (C@O), 71.7 (O–CH), 42.7
(CH2–Cl), 34.4 (CH2 ( ) (C@O)), 32.2 (CH2–CH2–CH3), 29.9, 29.8, 29.7, 29.6, 29.4,
1,3-Dichloro-2-propyl 3-nitrobenzoate (3 m): 1H NMR (CDCl3), d: 8.87 (s, 1H,
CHar), 8.42 (dd, J1 = 25.0 Hz, J2 = 8.2 Hz, 2H, CHar), 7.69 (t, J = 8.2 Hz, 1H, CHar),
5.48 (quin, J = 5.1 Hz, 1H, O–CH), 3.90 (d, J = 5.5 Hz, 4H, 2 CH2–Cl). 13C RMN
(CDCl3), d: 163.8 (C@O), 151.1 (Car–NO2), 134.7 (Car–C@O), 130, 129.8, 122.7
(CHar), 73.3 (O–CH), 42.5 (CH2–Cl).
a
29.3 (CH2), 25.1 (CH2
(C@O)), 22.9 (CH2-CH3), 14.4 (CH3). HRMS (EI+)
(b)
calculated for C11H20O2Cl2: 352.1936. Found: 352.1932.
1,3-Dichloro-2-propyl laureate (3d): 1H NMR (CDCl3), d: 5.18 (quin, J = 5.2 Hz,
1H, O–CH), 3.73 (dd, J1 = 5.4 Hz, J2 = 2 Hz, 4H, 2 CH2–Cl), 2.37 (t, J = 7 Hz, 2H,
1,3-Dichloro-2-propyl 3,5-dinitrobenzoate (3n): 1H NMR (COCD6), d: 9.17 (t,
J = 2.1 Hz 1H, CHar), 9.10 (d, J = 2.1 Hz, 2H, CHar), 5.67 (quin, J = 5.1 Hz, 1H, O–
CH), 4.11 (d, J = 5.1 Hz, 4H, CH2–Cl). 13C RMN (COCD6), d: 164.4 (C@O), 149.1
(Car–NO2), 134.3 (Car–C@O), 128.0, 122.8 (CHar), 76.3 (O–CH), 43.5 (CH2–Cl).
1,3-Dichloro-2-propyl 1-naphthoate (3o): 1H NMR (CDCl3), d: 8.93 (dd,
J1 = 8.8 Hz, J2 = 0.8 Hz, 1H, CHar), 8.28 (dd, J1 = 7.6 Hz, J2 = 1.6 Hz, 1H, CHar),
8.07 (d, J = 8.4 Hz, 1H, CHar), 7.91 (d, J = 7.6 Hz, 1H, CHar), 7.65 (m, 1H, CHar),
7.54 (m, 2H, 2 CHar), 5.54 (quin, J = 4.8 Hz, 1H, O–CH), 3.96 (d, J = 4.8 Hz, 4H, 2
CH2–Cl). 13C RMN (CDCl3), d: 166.3 (C@O), 134.4, 134.1, 131.6, 131.2, 128.9,
128.4, 126.6, 125.9, 125.8, 124.8 (CHar), 72.4 (O–CH), 42.8 (CH2–Cl).
1,3-Dichloro-2-propyl 2-naphthoate (3p): 1H NMR (CDCl3), d: 8.58 (s, 1H, CHar),
8.01 (dd, J1 = 8.8 Hz, J2 = 1.6 Hz, 1H, CHar), 7.92 (d, J = 8.4 Hz, 1H, CHar), 7.84 (d,
J = 8.8 Hz, 1H, CHar), 7.83 (d, J = 8 Hz, 1H, CHar), 7.53 (m, 2H, 2 CHar), 5.44 (quin,
J = 4.8 Hz, 1H, O–CH), 3.88 (d, J = 4.8 Hz, 4H, 2 CH2–Cl). 13C RMN (CDCl3), d:
165.8 (C@O), 136.0, 132.7, 131.9, 129.7, 128.9, 128.6, 128.0, 127.1, 126.6, 125.4
(CHar), 72.4 (O–CH), 42.7 (CH2–Cl).
CH2 ( ) (C@O)), 1.65 (m, 2H, CH2 (b) (C@O)), 1.26 (m, 24H, CH2), 0.88 (t, J = 7 Hz,
a
3H, CH3). 13C RMN (CDCl3), d: 173.0 (C@O), 71.7 (O–CH), 42.7 (CH2–Cl), 34.3
(CH2
(CH2
(C@O)), 32.1 (CH2–CH2–CH3), 29.8, 29.6, 29.5, 29.4, 29.3, (CH2), 25.1
(C@O)), 22.9 (CH2-CH3), 14.3 (CH3).
(a)
(b)
1,3-Dichloro-2-propyl caprylate (3e): 1H NMR (CDCl3), d: 5.12 (quin, J = 5.1 Hz,
1H, O–CH), 3.74 (dd, J1 = 5.5 Hz, J2 = 2.0 Hz, 4H, 2 CH2–Cl), 2.34 (t, J = 7.8 Hz, 2H,
CH2 ( ) (C@O)), 1.63 (quin, J = 7.4 Hz, 2H, CH2 (b) (C@O)), 1.29 (m, 8H, CH2), 0.87
a
(t, J = 7.0 Hz, 3H, CH3). 13C RMN (CDCl3), d: 173.0 (C@O), 72.0 (O–CH), 42.0
(CH2–Cl), 34.4 (CH2
(C@O)), 32.1 (CH2–CH2–CH3), 29.5 (CH2), 25.0 (CH2
(
a
)
(b)
(C@O)), 22.5 (CH2-CH3), 14.5 (CH3).
1,3-Dichloro-2-propyl 2-furoate (3f): 1H NMR (CDCl3), d: 7.62 (m, CHar), 7.26 (dt,
J1 = 3.5 Hz, J2 = 0.8 Hz, 1H, CHar), 6.53 (m, 1H, CHar), 5.39 (quin, J = 5.1 Hz, 1H,
O–CH), 3.85 (d, J = 5.6 Hz, 4H, CH2–Cl). 13C RMN (CDCl3), d: 156.9 (C@O), 146.5
(CHar), 143.7 (CHar–C@O), 119.8, 112.1 (CHar), 72.3 (O–CH), 43.1 (CH2–Cl).
1,3-Dichloro-2-propyl 2-thiophencarboxylate (3g): 1H NMR (CDCl3), d: 7.79 (dd,
J1 = 3.9 Hz, J2 = 1.2 Hz, 1H, CHar), 7.55 (dd, J1 = 5.1 Hz, J2 = 1.2 Hz, 1H, CHar), 7.06
(dd, J1 = 5.0 Hz, J2 = 3.9 Hz, 1H, CHar), 5.31 (quin, J = 5.1 Hz, 1H, O–CH), 3.80 (d,
J = 5.1 Hz, 4H, CH2–Cl). 13C RMN (CDCl3), d: 161.1 (C@O), 144.8 (CHar), 143.8
(CHar–C@O), 122.5, 118.1 (CHar), 72.2 (O–CH), 42.8 (CH2–Cl).
7. Experimental procedure.
A mixture of palmitic acid (1 mequiv), glycerol
(2 mequiv), Crown-18 ether (0.125 mequiv, 10% mol), potassium chloride
(5 mequiv) and [BMIM][PF6] (2.5 g) was stirred in a 10-mL reactor for 48 h at
100 °C. The crude reaction mixture was extracted with hexane (3 Â 2 mL) while
stirring in a circular shaker placed into an oven for 30 min at 40 °C. The upper
phase was recovered and dried over anhydrous sodium sulfate. Organic
solution was filtered and evaporated to dryness. Yield was determined using 1H
NMR with 1,4-dichlorobenzene13 as internal standard.
1,3-Dichloro-2-propyl benzoate (3h): 1H NMR (CDCl3), d: 8.00 (m, 1H, CHar
(a)
(C@O)), 7.53 (m, 1H, CHar), 7.39 (m, 2H, CHar), 5.36 (quin, J = 5.3 Hz, 1H, O–CH),
3.82 (m, 4H, 2 CH2–Cl). 13C RMN (CDCl3), d: 163.4 (C@O), 131.7,127.9, 127.2,
126.6 (Car), 70.1 (O–CH), 40.5 (CH2–Cl).
1,3-Dichloro-2-propyl cinnamate (3i): 1H NMR (CDCl3), d: 7.73 (d, J = 15.6 Hz,
1H, CHar), 7.48 (m, 2H, 2 CHar), 7.34 (m, 3H, 2 CHar, Ph–CH@CH), 6.41 (m, 1H,
Ph–CH@CH), 5.25 (quin, J = 5.1 Hz, 1H, O–CH), 3.76 (d, J = 5.5 Hz, 4H, 2 CH2–Cl).
13C RMN (CDCl3), d: 165.9 (C@O), 146.7 (Ph–CH@CH), 134.2 (Car), 130.9, 129.2,
128.5 (CHar), 117.0 (Ph–CH@CH), 71.9 (O–CH), 42.7 (CH2–Cl).
1,3-Dichloro-2-propyl palmitate (3a): 1H NMR (CDCl3), d: 5.18 (quin, J = 5.2 Hz,
1H, O–CH), 3.73 (m, 4H, 2 CH2–Cl), 2.37 (t, J = 7 Hz, 2H, CH2 ( ) (C@O)), 1.65 (m,
a
2H, CH2
(C@O)), 1.26 (m, 24H, CH2), 0.88 (t, J = 7 Hz, 3H, CH3). 13C RMN
(b)
(CDCl3), d: 172.7 (C@O), 71.5 (O–CH), 42.5 (CH2–Cl), 34.1 (CH2
(C@O)), 31.9
(a)
(CH2–CH2–CH3), 29.7, 29.6, 29.5, 29.4, 29.3, 29.2, 29.0 (CH2), 24.8 (CH2
(C@O)), 22.7 (CH2–CH3), 14.1 (CH3).
(b)
1,3-Dichloro-2-propyl salicylate (3j): 1H NMR (CDCl3), d: 7.81 (dd, J1 = 8.2 Hz,
J2 = 1.7 Hz, 1H, CHar), 7.50 (m, 1H, CHar), 6.95 (d, J = 7.5 Hz, 1H, CHar), 6.80 (m,
8. (a) Pews, R. G.; Davis, R. A. Chem. Commun. 1973, 269; (b) Derbesy, M.; Naudet,
M. Bull. Soc. Chim. France 1968, 4531–4539; (c) Nayler, J. H. C. J. Chem. Soc. 1959,
189–195.
9. Méndez, J. J.; Eras, J.; Balcells, M.; Canela, R. Synth. Commun. 2006, 36, 1167–
1175.
10. D’Anna, F.; La Marca, S.; Noto, R. J. Org. Chem. 2008, 73, 3397–3403.
11. Yau, H. M.; Barnes, S. A.; Hook, J. M.; Youngs, T. G. A.; Croft, A. K.; Harper, J. B.
Chem. Commun. 2008, 3576–3578.
12. Chiappe, C. In Ionic Liquids in Synthesis; Welton, T., Wasserscheid, P., Eds.; Ionic
Liquids in Organic Synthesis: Effects on Rate and Selectivity; Wiley-VCH:
Wheinheim, 2007; pp 265–292.
1H, CHar), 5.39 (quin, J = 5.1 Hz, 1H, O–CH), 3.82 (d, J = 5.5 Hz, 4H, 2 CH2–Cl). 13
C
RMN (CDCl3), d: 169.1 (C@O), 162.1 (Car-OH), 136.7, 130.3, 119.7, 117.9, 111.8
(CHar), 72.7 (O–CH), 42.5 (CH2–Cl).
1,3-Dichloro-2-propyl 2-chlorobenzoate (3k): 1H NMR (CDCl3), d: 7.88 (m, 1H,
CHar), 7.47 (td, J1 = 7.8 Hz, J2 = 1.6 Hz, 2H, CHar), 7.35 (m, 1H, CHar), 5.44 (quin,
J = 5.2 Hz, 1H, O-CH), 3.89 (d, J = 5.5 Hz, 4H, 2 CH2–Cl). 13C RMN (CDCl3), d:
164.5 (C@O), 134.4 (Car–OH), 133.4, 131.9, 131.5, 129.1, 126.9 (Car), 72.9 (O–
CH), 42.5 (CH2–Cl).
1,3-Dichloro-2-propyl 3-aminobenzoate (3 l): 1H NMR (CDCl3), d: 5.38 (quin,
J = 5.0 Hz, 1H, O–CH), 3.90 (d, 4H, J = 5.1 Hz, 2 CH2–Cl). 13C RMN (MeOD), d:
166.1 (C@O), 148.4 (Car-NH2), 130.1 (Car-C@O), 129.0, 119.9, 118.8, 115.7
(CHar), 72.6 (O–CH), 42.6 (CH2–Cl). HRMS (EI+) calculated for C11H20O2Cl2:
247.0167. Found: 247.0162.
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415.