Efficient synthesis of 16 aromatic Morita-Baylis-Hillman adducts: Biological evaluation on Leishmania amazonensis and Leishmania chagasi

Article abstract of DOI:10.1016/j.bioorg.2010.08.002

Sixteen aromatic Morita-Baylis-Hillman adducts (MBHA) 1-16 were efficiently synthesized in a one step Morita-Baylis-Hillman reaction (MBHR) involving commercial aldehydes with methyl acrylate or acrylonitrile (81-100% yields) without the formation of side

Full text of DOI:10.1016/j.bioorg.2010.08.002

Bioorganic Chemistry 38 (2010) 279–284
Contents lists available at ScienceDirect
Bioorganic Chemistry
journal homepage: www.elsevier.com/locate/bioorg
Efficient synthesis of 16 aromatic Morita–Baylis–Hillman adducts: Biological
evaluation on Leishmania amazonensis and Leishmania chagasi
Cláudio G.L. Junior a, Priscila A.C. de Assis b, Fábio P.L. Silva a, Suervy C.O. Sousa a, Natália G. de Andrade a,
Ticiano P. Barbosa a, Patrícia L.N. Nerís b, Luiz V.G. Segundo a, Ítalo C. Anjos a, Gabriel A.U. Carvalho a,
a,
Gerd B. Rocha a, Márcia R. Oliveira b, , Mário L.A.A. Vasconcellos
⇑
⇑⇑
a Departamento de Química, Universidade Federal da Paraíba, Campus I, João Pessoa, PB 58059-900, Brazil
b Departamento de Biologia Molecular, Universidade Federal da Paraíba, Campus I, João Pessoa, PB 58059-900, Brazil
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 1 July 2010
Available online 19 September 2010
Sixteen aromatic Morita–Baylis–Hillman adducts (MBHA) 1–16 were efficiently synthesized in a one step
Morita–Baylis–Hillman reaction (MBHR) involving commercial aldehydes with methyl acrylate or acry-
lonitrile (81–100% yields) without the formation of side products on DABCO catalysis and at low temper-
ature (0 °C). The toxicities of these compounds were assessed against promastigote form of Leishmania
amazonensis and Leishmania chagasi. The low synthetic cost of these MBHA, green synthetic protocols,
easy one-step synthesis from commercially available and cheap reagents as well as the very good antile-
Keywords:
Leishmania
Morita–Baylis–Hillman adducts
Temperature effect
Drugs
ishmanial activity obtained for 14 and 16 (IC50 values of 6.88
L. amazonensis; 9.58
g mLÀ1 and 14.34 g mLÀ1 respectively on L. chagasi) indicates that these MBHA
can be a novel and promising class of anti-parasitic compounds.
Ó 2010 Elsevier Inc. All rights reserved.
l l
g mLÀ1 and 11.06 g mLÀ1 respectively on
l
l
Structure–activity-relationship
1. Introduction
prepared in a few steps and in good yields is a challenge that is
being achieved by some research groups [12–16].
Leishmaniasis are a complex of diseases, caused by different
species of Leishmania sp. protozoan parasite, which have significant
impact on the world, especially in developing countries with infec-
tions spread over several hundred million people and a significant
cause of morbidity and mortality [1–4]. It causes around 70,000
deaths annually, as well as the occurrence of 2 million new cases,
with an estimated 12 million people presently infected worldwide
[1]. So far no vaccine approved for human use is available [5]. The
treatment options for leishmaniasis are limited and involve the
administration of pentavalent antimonial agents as first line drugs:
sodium stibogluconate (PentostanÒ) and meglumine antimonite
(GlucantimeÒ). The amphotericin B and pentamidine are second
choice drugs [6]. However, these drugs are expensive, potentially
toxic and require long-term treatment [7].
The scientific evaluation of medicinal plants has provided some
alternatives drugs, [8–11] but the small quantities extracted from
plants and/or the vast molecular complexity of these structures
makes the mass production of these natural drugs impractical both
through natural extraction and chemical synthesis. Thus, the
discovery and identification of relatively simple drugs that can be
The Morita–Baylis–Hillman reaction (MBHR) is an important
way for C–C bond formation [17]. It involves the coupling of al-
kenes containing electron-withdrawing groups (EWG) with alde-
hydes, ketones or imines, among others [18–22]. Tertiary amines
are used as nucleophilic catalysts of which 1,4-diazabicy-
clo[2.2.2]octane (DABCO) is the most widely used (Scheme 1).
The Morita–Baylis–Hillman adducts (MBHA) have been extensively
used as starting materials in organic synthesis for a variety of
applications, many of which have biological activity [23–26]. An
inconvenience associated with this reaction are the long reaction
times. There are reports of reactions that, last up to 65 days [18].
Due to the synthetic utility of these MBHA, several protocols have
been described to improve the reaction time and yields, such as the
use of microwaves [27], ultrasound [28], high pressures [29], use of
ionic liquids [30], and other protocol variations [18–22].
The bioactivity of some aromatic MBHA was first described in
1999 against Plasmodium falciparum, the etiologic agent of malaria
[31,32]. In 2006, the molluscicidal activities of ten aromatic MBHA
were described effectively against Biomphalaria glabrata (Say)
snails, the intermediate host of schistosomiasis [33]. Also that year
Kohn et al. showed in vitro antiproliferative effect of some MBHA
derivatives on human tumor cell lines [34]. Kohn et al. also showed
that aromatic MBHA derivatives had a better bioactivity when
compared to aliphatic ones [34]. Subsequently a high in vitro leish-
manicidal activity was also described for some MBHA, effective
⇑
Corresponding author. Fax: +55 83 3216 7433.
Corresponding author. Fax: +55 83 3216 7433.
E-mail addresses: mrosa@dbm.ufpb.br (M.R. Oliveira), mlaav@quimica.ufpb.br
⇑⇑
(M.L.A.A. Vasconcellos).
0045-2068/$ - see front matter Ó 2010 Elsevier Inc. All rights reserved.
doi:10.1016/j.bioorg.2010.08.002

280
C.G.L. Junior et al. / Bioorganic Chemistry 38 (2010) 279–284
Table 1
O
OH
Use of tBuOH:water (6:4) as mixture solvents,
1
Equiv. of DABCO on r.t. as
NR3
EWG
EWG
experimental condition to prepare the MBHA 2, 4, 6, 8, 10, 12, 14 and 16.
+
R
R
Entry
MBHA
Rate (h)
Yield (%)
1
2
3
4
5
6
7
8
2
4
6
1.5
2
5
24
24
24
5
95
R = alkyl, aryl, H
EWG = CO2R, CN, COR, others
70b
75a
70a
55a
75
MBHA
8
Scheme 1. The Morita–Baylis–Hillman reactions with, e.g. aldehydes.
10
12
14
16
58b
>10
240
against the Leishmania amazonensis [35] and Leishmania chagasi
parasites [36]. Recently, we described that the MBRA 3-Hydroxy-
2-methylene-3-(4-nitrophenyl propanenitrile) is a new highly ac-
tive compound against epimastigote and trypomastigote form of
Trypanosoma cruzi, the parasite that causes Chagas disease [37].
In connection with our continuum interest in organic synthesis
of products with biological activity [38–42] our research group has
been engaged in the development of several new conditions to pro-
duce MBHA in high yields from ‘‘one-pot reaction”, [43–45] we
present here a very efficient synthetic protocol for the preparation
of the sixteen aromatic MBHA 1–16 (Fig. 1) in very high yields and
subsequently in vitro antipromastigote biological evaluation on L.
amazonensis (the primary cause of the tegumentary leishmaniasis)
and L .chagasi. A relationship between the chemical structure and
biological activity (structure–activity-relationship, SAR) is also
being proposed in this article based on our previous theoretical
conformational calculations [46], and on biological results ob-
tained here.
a
One co-product formation.
Two co-products formation.
b
and 3-nitrobenzaldehyde is a very reactive and cheap reagent, we
have decided to find an efficient experimental protocol to optimize
the synthesis of 4 and then apply such protocol to synthesize
MBHA 1–16. The results are shown in Scheme 2 and Table 2.
Table 2 (Entry 3) points out a new and efficient methodology,
through which MBHA 4 can be quantitatively prepared without
solvents and at low temperatures. The use of ultrasound method-
ology did not improve reaction rate (see Entries 1 versus 2 and En-
try 3 versus 4). In fact, use of the ultrasound decreased the yield at
low temperatures (Entries 3 versus 4).
There are reports in literature that described increased effi-
ciency of MBHR when the temperature is reduced from r.t. to
0 °C [49]. We can understand these experimental results based
on the accepted mechanism proposed for the MBHR [50,51]. The
highly organized transitions states involved on the slow steps of
the currently accepted MBHR mechanisms, proposed by McQuade
et al. [50] and Aggarwal et al. [51], and corroborated by Coelho
et al. [52], suggests that the entropy of activation is a very impor-
tant parameter in this reaction. In fact, the volume of activation of
MBHR (À70 cm3/mol) [53] is one of the highest in absolute values
among known reactions [54]. Therefore, it is a reasonable assump-
tion that the reduction of temperature from r.t. to 0 °C makes the
2. Results and discussion
Due to higher reactivity of acrylonitrile versus methyl acrylate
on MBHR, we have started our work with the synthesis of adducts
2, 4, 6, 8, 10, 12, 14 and 16 (Fig. 1). The rate and yields of MBHA
preparations is very sensible to solvent structure [47,48]. Recently,
we have described that tBuOH:water (6:4) was a good selective sol-
vent mixture to prepare some MBHA [44]. In Table 1 we present
our first results for 2, 4, 6, 8, 10, 12, 14 and 16 preparations using
these conditions.
We notice in Table 1 that only the preparation of 2 was remark-
ably efficient (95%, isolated product, Entry 1). All the other prod-
ucts were prepared in moderate yields and in some cases it was
observed one or two co-products formation (Entries 2–7, Table
1). Preparation of 16 was not possible using this methodology (En-
try 8, Table 1). Since the preparation of 4 led to two side products
entropic term (ÀTÁ
DS > 0) less important, reducing Gibbs activa-
tion energy, thus improving MBHR rate in comparison with the
rate of co-products formation and consequently increasing the
selectivity of this reaction. The results for MBHA 1–16 synthesis
using this very efficient methodology are shown in Table 3.
This methodology was highly efficient to prepare the all MBHA,
except 15 (entry 16, Table 3). The addition of methanol as solvent,
however, led to the quantitative preparation of 16 without side
OH
OH
OH
NO2 OH
N
R
O2N
R
R
R
O2N
5 R=CO2CH3
6 R=CN
7 R=CO2CH3
8 R=CN
1 R=CO2CH3
2 R=CN
3 R=CO2CH3
4 R=CN
OH
OH
OH
OH
R
R
R
R
N
N
Br
13 R=CO2CH3
14 R=CN
15 R=CO2CH3
16 R=CN
9 R=CO2CH3
10 R=CN
11 R=CO2CH3
12 R=CN
Fig. 1. Synthesized and biologically evaluated 1–16 MBHA.

C.G.L. Junior et al. / Bioorganic Chemistry 38 (2010) 279–284
281
O
OH
O2N
CN
1 Equiv. DABCO
CONDITION
O2N
CN
+
1 mmol
0.4mL
4
Scheme 2. Experimental protocols in the optimization of the preparation of 4.
Table 2
Table 4
Use of low temperature and ultrasound as protocols to optimize the synthesis of 4
MBHA.
IC50 to 1–16 MBHA from promastigote forms of Leishmania amazonensis and
Leishmania chagasi.
Entry
Condition
Rate (min.)
Yield (%)
MBHA
L. amazonensis
g mLÀ1
L. chagasi
g mLÀ1
1
2
3
4
r.t.
20
70
20
40
85a
90b
100
84b
l
l
M
l
lM
Ultrasound, r.t.
0 °C
Ultrasound, 0 °C
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
46.53
26.19
107.12
48.65
11.88
12.66
141.30
48.50
86.65
62.75
94.47
40.15
20.23
6.88
196.16
128.27
451.58
238.27
50.08
27.85
18.86
64.67
23.24
19.52
16.66
138.99
37.49
67.66
36.62
95.50
32.08
23.08
11.06
33.03
14.34
117.41
92.37
262.63
113.82
82.29
a
Two co-products formation.
One co-product formation.
b
62.00
81.59
731.37
302.80
448.50
391.77
488.98
250.95
83.50
32.88
85.54
40.23
724.59
234.06
350.57
228.88
494.81
200.50
95.37
52.92
122.33
60.50
Table 3
Optimized protocols for the preparation of 1–16 MBHA. All reactions were performed
at 0 °C.
Entry
MBHA
Rate
Yield (%)a
1
2
3
1
2
3
3 h
15 min
2 h
85
100
98
23.19
9.58
4
5
4
5
25 min
3 h
100
92
6
7
8
9
6
7
8
9
40 min
5 h
30 min
2 h
100
95
100
98
due to the long distance between the OH and the nitrogen of the
nitrile group (OHÁ Á ÁNC, more than 4 Å, Fig. 2).
Based on these data we believe that the likely formation of the
intramolecular hydrogen bond (IHB) between the hydroxyl and es-
ter carbonyl function (OHÁ Á ÁO@C) into 1, 3, 5, 7, 9. 11, 13 and 15
can decrease their interaction with enzyme active site hydrogen
bond donor (HBD) and acceptor (HBA) groups. On the other hand,
as the nitrogen atom of the nitrile group and the hydroxyl group in
2, 4, 6, 8, 10, 12, 14 and 16 cannot form IHB between each other,
these groups efficiently bind with enzyme active site hydrogen
bond donor (HBD) and acceptor (HBA) groups, which could explain
their higher biological activity (Fig. 2).
10
11
12
13
14
15
16
17
10
11
12
13
14
15
15
16
50 min
2 h
10 min
16 days
10 h
>20 days
3 daysb
4 h
100
81
100
85
98
0
90
98
a
Isolated products.
Using 0.5 mL methanol/mmol as solvent.
b
Interestingly, we can see in Table 4 that the leishmanicidal
activity is almost equivalent between compounds 5 and 6. We have
also characterized by QTAIM study a seven member IHB between
the o-nitro group in the aromatic ring and hydroxyl (N@OÁ Á ÁHAO)
in MBHA 6 (Fig. 3) [46]. This IHB can inhibit the efficiency of hydro-
xyl group as HBD and the nitro group as HBA, approximating the
leishmanicidal activities of those two molecules. It is important
product formation (Entry 17, Table 3). After a simple filtration the
products were ready for biological assays which further reiterate
this methodology easy handling when increasing the scale of the
procedure.
The sixteen adducts evaluated by MTT colorimetric method
showed a significant antileishmanial activity with IC50 values for
L. amazonensis and L. chagasi ranged from 6.88
l
g mLÀ1 to
141.30
l
g mLÀ1 and 11.06 g mLÀ1 to 138.99 g mLÀ1, respec-
l
l
H
tively (Table 4). The inhibition of promastigote growth caused by
MBHA was larger than that caused by Glucantime, the reference
drug (IC50 > 8.0 mg/mL). We present in Table 4 the results of the
in vitro toxicities of 1–16 on L. amazonensis and L. chagasi.
O
O
OH
N
O
We can see in Table 4, that in general, nitrile-containing adducts
(MBHA2, 4, 8, 10, 12, 14 and 16)aremuchmoreactiveagainstL. ama-
zonensis and L. chagasi than the compounds 1, 3, 7, 9, 11, 13 and 15,
which contain carboxymethylester moiety in their structure.
In the other paper a six member intramolecular hydrogen bond
(IHB) between the hydroxyl and ester carbonyl function
(OHÁ Á ÁO@C, 2.1 Å) was characterized by a QTAIM study into the
2-[Hydroxy(phenyl)methyl]propanoate MBHA [46], but no IHB
involving 2-[Hydroxy(phenyl) methyl] acrylonitrile was observed
no IHB
IHB
CN
HO
O ---HO
o
o
>4A
2.1A
Fig. 2. 2-[hydroxy(phenyl)methyl]propanoate (drawing on the left, with the IHB
formation) and 2-[hydroxy (phenyl) methyl]acrylonitrile (drawing on the right, no
IHB formation).

282
C.G.L. Junior et al. / Bioorganic Chemistry 38 (2010) 279–284
4.1.2.2. 2-[Hydroxy(4-nitrophenyl)methyl]acrylonitrile (2) [36]. IR
(KBr): 3447, 3115, 2228, 1599, 1520, 1348, 736 cmÀ1 1H NMR
(200 MHz, CDCl3) d 8.21(d, J = 8.8 Hz, 2H); 7.58 (d, J = 9.0 Hz, 2H);
6.07 (d, J = 0.8 Hz, 1H); 6.16 (d, J = 0.6 Hz, 1H); 5.42 (s, 1H); 3.23
(brs, 1H, CHOH). 13C NMR (CDCl3, 50 MHz): d 73.01; 116.62;
123.92(2C); 126.13; 127.34(2C); 130.51; 146.80; 147.82.
H
O
O
;
N
O
N
4.1.2.3. 2-[Hydroxy(3-nitrophenyl)methyl]propanoate (3) [55]. 1H
NMR (CDCl3, 200 MHz): d 8.22 (t, J = 1.8 Hz, 1H); 8.08–8.13 (m,
1H); 7.69–7.73 (m, 1H); 7.50 (t, J = 8 Hz, 1H); 6.38 (s, 1H); 5.89
(s, 1H); 5.60 (d, J = 4.4 Hz, 1H); 3.70 (sl, 3H); 3.46 (d, J = 5.4 Hz,
d (ppm): 52.2(1C), 72.5(1C),
121.5(1C), 122.7(1C), 127.2(1C), 129.3(1C), 132.7(1C), 140.9(1C),
143.5(1C), 148.2(1C), 166.3(1C).
6
Fig. 3. Seven members IHB (NO2Á Á ÁHO) in compound 6.
1H). 13C NMR (CDCl3, 50 MHz)
to emphasize that the computational studies which characterized
the IHBs were performed considering implicit aqueous environ-
ment. The study of the biological mechanism of action of these ad-
ducts will now be investigated.
4.1.2.4. 2-[Hydroxy(3-nitrophenyl)methyl]acrylonitrile (4) [36]. IR
(KBr): 3345, 3105, 2239, 1583, 1520, 1348 cmÀ1
;
1H NMR
3. Conclusion
(200 MHz, CDCl3)
d 8.24 (dd, J = 1.8/1.6 Hz, 1H); 8.18 (ddd,
J = 8.0/1.0/1.2 Hz, 1H); 7.57 (t, J = 8.0 Hz, 1H); 7.75 (ddd, J = 7.8/
1.6 Hz, 1H); 6.09 (d, J = 0.8 Hz, 1H); 6.20 (d, J = 1.6 Hz, 1H); 5.43
(s, 1H); 3.02 (brs, 1H, CHOH). 13C NMR (CDCl3, 100 MHz) d
72.66(1C), 116.31(1C), 121.14(1C), 123.35(1C), 125.01(1C),
129.73(1C), 131.52(1C), 132.53(1C), 141.21(1C), 147.98(1C).
In this article we have presented new protocols to synthesize
aromatic MBHA 1–16 in one-step synthesis, under conditions suit-
able for scaling up and with high yields. All adducts were very ac-
tive against L. amazonenesis and L. chagasi. The remarkable
antileishmanial activity obtained for 14 and 16 (IC50 values of
6.88
9.58
l
l
g mLÀ1 and 11.06
g mLÀ1 and 14.34
l
l
g mLÀ1 respectively on L. amazonensis;
g mLÀ1 respectively on L. chagasi) as well
4.1.2.5. 2-[Hydroxy(2-nitrophenyl)methyl]propanoate (5) [41]. 1H
NMR (CDCl3, 200 MHz): d 7.92(dd, J = 8.2/1.2 Hz, 1H); 7.73 (dd,
J = 7.8/1.8 Hz, 1H); 7.62 (ddd, J = 7.8/1.2/1.0 Hz, 1H); 7.43 (ddd,
J = 8.0/1.6/1.6 Hz, 1H); 6.38 (s, 1H); 5.89 (d, 1H); 5.60(d,
J = 4.4 Hz, 1 Hz); 3.70 (s, 3H); 3.60 (d, J = 5.4 Hz, 1H). 13C NMR
(CDCl3, 100 MHz) d 52.20(1C), 67.56(1C), 124.55(1C), 126.48(1C),
128.67(2C), 133.47(1C), 136.05(1C), 140.65(1C), 148.32(1C),
166.39(1C).
as the easy one-step synthesis from cheap and commercially avail-
able aldehydes through a green chemistry procedure indicates that
these MBHA can be a novel and promising class of anti-parasitic
compounds.
4. Experimental
4.1. Chemistry
4.1.2.6. 2-[Hydroxy(2-nitrophenyl)methyl]acrylonitrile (6) [36]. IR
(KBr): 3345, 2228, 1348, 1609, 1520 cmÀ1 1H NMR (200 MHz,
;
4.1.1. Materials and methods
CDCl3) d 8.01(dd, J = 8.0/1.4 Hz, 1H); 7.84 (dd, J = 6.0/1.8 Hz, 1H);
7.72 (ddd, J = 8.0/1.8/1.4 Hz, 1H); 7.52 (ddd, J = 8.0/1.6/1.4 Hz,
1H); 6.12 (d, J = 1.4 Hz, 1H); 6.09 (d, J = 1.2 Hz, 1H); 5.98 (s, 1H).
13C NMR (CDCl3, 100 MHz) d 69.13(1C), 116.51(1C), 124.30(1C),
125.07(1C), 129.11(1C), 129.71(1C), 132.03(1C), 134.16(1C),
134.30(1C), 147.93(1C).
Commercially available reagents were purchased from Aldrich
and used without further purification. The compounds synthesized
in this work are not new. The MBH adducts 1–16 were character-
ized using NMR by comparison with the compounds described in
literature. 1H and 13C NMR spectra were obtained by using a Mer-
cury Spectra AC 200 (200 MHz for 1H and 50.3 MHz for 13C) in
CDCl3 or Varian Spectra V NMR S-500 (100 MHz for 13C). The Fou-
rier Transform Infrared Spectroscopy spectra were obtained using
a spectrophotometer IR-Prestige-21 (Shimadzu). TLC was done by
using the flexible plates for TLC silica gel Kieselgel 60 (Whatman)
and spots were visualized with short wavelength UV light 254 nm.
4.1.2.7. 2-[Hydroxy(pyridin-2-yl)methyl]propanoate (7) [41]. 1H
NMR (CDCl3, 200 MHz) d (ppm): 8.51 (d, J = 4.4 Hz, 1H); 7.66
(ddd, J = 7.8/1.6 Hz, 1H); 7.4 (d, J = 8.0 Hz, 1H); 7.21 (m, 1H);
6.34(sl, 1H); 5.96 (sl, 1H); 5.61(sl, 1H); 3.71 (s, 3H); 13C NMR
(CDCl3, 50 MHz)
d
(ppm): 51.8(1C), 72.0(1C), 121.2(1C),
122.6(1C), 126.8(1C), 136.8(1C), 141.5(1C), 148.1(1C), 159.4(1C),
166.4(1C).
4.1.2. General protocols for the MBHA preparations
Reactions were carried out using the corresponding aldehydes
(1 mmol), 0.5 mL of acrylonitrile or methyl acrylate and 1 mmol
of DABCO at 0 °C for x min/h/day (Table 3). To synthesize MBHA
15 we used 0.5 mL/mmol of methanol as solvent (Entry 16, Table
3). After that, the reaction media was directly filtered through sil-
ica gel, using AcOEt:hexane (2:8) as solvent and the reaction prod-
ucts were concentrated under reduced pressure. The products
were then ready for bioevaluation without the need of further
purification.
4.1.2.8. 2-[Hydroxy(pyridin-2-yl)methyl]acrylonitrile (8) [36]. IR
(Film) 3200, 2225, 1600 cmÀ1 1H NMR (CDCl3, 200 MHz): d 8.56
.
(ddd, J = 8.0/1.4 Hz, 1H); 7.75 (ddd, J = 7.8/7.6/1.6 Hz, 2H); 7.37
(d, J = 7.8 Hz, 1H); 7.29 (ddd, J = 0.8/1.0/1.2 Hz, 1H); 5.28 (s, 1H);
6.21(s, 1H); 6.05(s, 1H). 13C NMR (CDCl3, 100 MHz) d 72.89(1C),
116.69(1C), 121.19(1C), 123.67(1C), 125.82(1C), 130.86(1C),
137.43, 148.47(1C), 156.09(1C).
4.1.2.9. 2-[Hydroxy(pyridin-3-yl)methyl]propanoate (9) [41]. 1H
NMR (CDCl3, 200 MHz) d (ppm):8.48(d, J = 2.0 Hz, 1H); 8.39(dd,
J = 5.0/1.5 Hz, 1H); 7.74 (ddd, J = 8.0/2.0/2.0 Hz, 1H); 7.28(m, 1H);
6.40(d, J = 0.6, 1H); 6.01(sl, 1H); 5,60(sl, 1H); 3,71(s, 3H).13C NMR
4.1.2.1. 2-[Hydroxy(4-nitrophenyl)methyl]propanoate (1) [41]. 1H
NMR (CDCl3, 200 MHz): d = 8.16 (d, 2H, J = 8.8 Hz), 7.54 (d, 2H,
J = 8.4 Hz), 6.36 (s, 1H), 5.86 (s, 1H), 5.60 (d, J = 5.8 Hz, 1H), 3.71
(s, 3H), 3.41 (d, J = 5.8 Hz, 1H). 13C NMR (CDCl3, 50 MHz) d
(ppm): 52.2(1C), 72.6(1C), 123.5(1C), 237.2(1C), 127.3(1C),
140.8(1C), 147.3(1C), 148.5(1C), 166.3(1C).
(CDCl3, 50 MHz)
d
(ppm): 52.0(1C), 70.5(1C), 123.4(1C),
126.1(1C), 134.7(1C), 137.6(1C), 141.6(1C), 148.2(1C), 148.4(1C),
166.2(1C).

C.G.L. Junior et al. / Bioorganic Chemistry 38 (2010) 279–284
283
4.1.2.10. 2-[Hydroxy(pyridin-3-yl)methyl]acrylonitrile (10) [36]. 1H
NMR (CDCl3, 200 MHz): d 8.41 (m, 2H); 7.79 (ddd, J = 7.8/1.8/
1.6 Hz, 1H); 7.33 (dd, J = 8.0 Hz, 1H); 6.05 (d, J = 1.0 Hz, 1H); 6.17
calculated from the ratio of OD readings in wells with compounds
versus wells without compounds  100. The concentration which
inhibits 50% of growth (IC50) was determined by regression analy-
sis using the SPSS 8.0 software for Windows. All experiments were
done at least three times and each experiment was performed in
triplicate.
(d, J = 1.2, 1H); 5.33 (s, 1H). 13C NMR (CDCl3, 100 MHz)
d
71.51(1C), 116.69(1C), 124.09(1C), 125.99(1C), 130.39(1C),
135.04(1C), 136.13(1C), 147.40(1C), 148.94(1C).
4.1.2.11. 2-[Hydroxy(pyridin-4-yl)methyl]propanoate (11) [56]. 1H
NMR (CDCl3, 200 MHz) d (ppm): 8.47 (dd, J = 4.6/1.6 Hz, 2H);
7.30 (dd, J = 4.6/1.6 Hz, 2H); 5.89 (s, 1H); 5.51 (s, 1H); 3.70 (s,
1H). 13C NMR (CDCl3, 50 MHz) d (ppm): 52.09(1C), 71.86(1C),
121.49(1C), 127.07(1C), 140.92(1C), 149.32(1C), 151.02(1C),
166.29(1C).
Acknowledgment
This work has been supported by CNPq, CAPES, FAPESQ-PB.
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