NaNO2-ceric ammonium nitrate mediated conversion of acrylic esters and Baylis-Hillman derived acrylic esters into corresponding β-nitro acrylic esters

Article abstract of DOI:10.1016/j.tet.2003.11.013

A variety of acrylic esters, including those derived from Baylis-Hillman reactions, react with NaNO₂-ceric ammonium nitrate to form the corresponding β-nitro alcohols 2 and 5 whose dehydration, via their mesylates, leads to β-nitro acrylic esters, in good to excellent yields. Further, β-nitro acrylic esters containing a mesylate group 6, obtained from the Baylis-Hillman products, react with NaN₃ to form 2-cyano-3-substituted acrylic esters 10 in excellent yields.

Full text of DOI:10.1016/j.tet.2003.11.013

Tetrahedron 60 (2004) 397–403
NaNO2–Ceric ammonium nitrate mediated conversion of acrylic
esters and Baylis–Hillman derived acrylic esters into
corresponding b-nitro acrylic estersq
K. Jayakanthan,a K. P. Madhusudananb and Yashwant D. Vankara
,
*
aDepartment of Chemistry, Indian Institute of Technology, Kanpur 208 016, India
bMedicinal Chemistry Division and RSIC, Central Drug Research Institute, Lucknow 226 001, India
Received 14 August 2003; revised 15 October 2003; accepted 6 November 2003
Abstract—A variety of acrylic esters, including those derived from Baylis–Hillman reactions, react with NaNO2–ceric ammonium nitrate
to form the corresponding b-nitro alcohols 2 and 5 whose dehydration, via their mesylates, leads to b-nitro acrylic esters, in good to excellent
yields. Further, b-nitro acrylic esters containing a mesylate group 6, obtained from the Baylis–Hillman products, react with NaN3 to form
2-cyano-3-substituted acrylic esters 10 in excellent yields.
q 2003 Elsevier Ltd. All rights reserved.
b-Nitro acrylic esters have been found to be excellent
dienophiles2 in organic synthesis. The nitro group in the
b-nitro acrylic esters, owing to its more powerful electron
withdrawing nature than the ester moiety, directs2e the
regiochemical outcome in Diels–Alder reactions. This
aspect has been elegantly used in the synthesis of
isogabaculine,3 gelesmine,4 and calicheamycinone.5 In
addition, the nitro group can be eliminated2b,h using a
base such as DBU thereby making b-nitro acrylic esters as
propiolic ester equivalents. Further, the nitro group can be
reduced5 to an amino functionality with NaBH4–NiCl2, and
to an amino4 and amino hydroxyl2c,d functionalities with
Al–Hg. Recently, such reductions of b-nitro acrylate
derived Diels–Alder adducts have been used in the
synthesis of polyhydroxylated cyclohexyl-b-amino acids6a
and in the asymmetric synthesis of (2)-oryzoxymycin.6b
Besides this, possibilities of employing the Nef reaction,1
and reductive elimination7 of the nitro group in Diels–Alder
adducts also exist to obtain nitro free products. Apart from
the studies in Diels–Alder reactions, b-nitro acrylic esters
have also been used as Michael acceptors. Recently,8a
nucleophiles derived from some amino acids and organo-
zinc cuprates8b–d have been added to b-nitro acrylic esters
especially in procuring optically active b-amino acids.8c,d
Michael addition on a b-nitro acrylic ester has also been
used in the synthesis of a ‘template for stabilization of a
peptide a-helix’.9 Overall, these studies clearly indicate the
importance of b-nitro acrylic esters in organic synthesis.
Preparation of b-nitro acrylic esters has been reported by
Shechter et al.10a by nitrating the corresponding acrylic
esters with dinitrogen tetroxide.10b Besides this, nitryl
chloride,11 nitrosyl chloride,12 fuming nitric acid12 and
NaNO2 –aq.CH3CO2H13 have also been employed to
prepare b-nitro acrylic esters from the corresponding acrylic
esters. Although these methods have found application, the
low boiling nature of some of these reagents makes them
inconvenient, especially if the reactions need to be done on
small scales. Further, a general and simple approach is
needed to prepare these class of compounds. Recently we
have reported14 NaNO2–ceric ammonium nitrate (CAN) in
CH3CN as a novel reagent system for one pot conversion of
olefins into vicinal nitro amides. In an attempt to explore the
scope of this reagent system, we have now found that acrylic
esters undergo smooth reaction with this reagent system
forming b-nitro alcohols 2 in good yields along with a small
amount (,5%) of b-nitro acrylates 3 (Scheme 1).
Compounds 2 were readily converted into 3 via their
mesylates by following modified McMurry’s method15 in
good yields (entries 1–3, Table 1). Thus, in our initial
q Part 11 in the series, ‘Chemistry of Nitro Compounds’. For part 10, see
Ref. 1.
Keywords: Ceric ammonium nitrate; Sodium nitrite; b-Nitro acrylic esters;
Baylis–Hillman derived acrylic esters.
*
Corresponding author. Tel.: þ91-512-2597169; fax: þ91-512-2590007;
e-mail address: vankar@iitk.ac.in
Scheme 1.
0040–4020/$ - see front matter q 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2003.11.013

398
K. Jayakanthan et al. / Tetrahedron 60 (2004) 397–403
Table 1.
Entry
Acrylic esters (1)
Yield (%)
R
R 1
R 2
2
3 (E:Z)
a
b
c
d
e
f
H
CH3
H
Ph
p-Tolyl
p-Anisyl
H
H
CH3
H
H
C2H5
CH3
CH3
C2H5
CH3
CH3
62
62
78
—
—
—
75 (1:0)
90 (1:0)
73 (1:0)
6412 (1:1.7)
81 (1:2)
57 (1:1)
H
Scheme 3.
experiments, the reaction of ethyl acrylate with NaNO2–
CAN in acetonitrile resulted in the formation of ethyl
2-hydroxy-3-nitro propionate 2a10a in 62% yield. Conver-
sion of this alcohol to trans-ethyl 3-nitro acrylate 3a (entry
1, Table 1) was performed via its mesylate in 75% yield.
Likewise, methyl methacrylate 1c and methyl crotonate 1b
also gave 2-hydroxy-3-nitro propionates 2b and 2c in 62 and
78% yields (entries b and c, Table 1) which were converted
to the corresponding b-nitro acrylates in 90 and 73% yields,
respectively. Interestingly, these b-nitro acrylates were
found to be exclusively E-isomers, possibly because of the
ensuing E1cB reaction on the corresponding mesylates. On
the other hand, cinnamic esters directly gave the corre-
sponding b-nitro acrylates, (entries d–f, Table 1) without
forming the intermediate hydroxy compounds, possibly
because of the extended conjugation in these molecules.
However, each of these compounds (3d–f) was obtained as
a mixture of the corresponding E and Z isomers as revealed
by their 1H NMR spectra (Section 1). Although the
mechanism of this reaction has not been investigated by
us, we presume that nitrite radicals formed upon oxidation16
of nitrite ions by CAN, add on to an acrylic ester as shown in
Scheme 2 forming an intermediate I. This intermediate
radical I can either be further oxidised to a carbocation II or
react with a nitrate radical to form III. Hydrolysis of III,
during work up, will lead to the observed product 2a.
Alternatively, the carbocation II will react with water to
form 2a. It is also likely that the intermediate III is derived
from carbocation II upon reaction with nitrate ions from
CAN.17 However, hydration of the carbocation II is unlikely
since the reaction conditions are anhydrous. Further, had the
Table 2.
Entry
Yield (%)
4 R
Ph
m-Cl-Ph
p-Cl-Ph
C2H5
5
6 (E:Z)
a
b
c
d
e
62
56
63
47
45
37 (0:1)
70 (0:1)
79 (0:1)
51 (1:13)
51 (0:1)
C3H7
carbocation formed it would have also reacted with
acetonitrile to form the corresponding amide via a typical
Ritter reaction18 which we have not observed. We, there-
fore, feel that the pathway via the radical formation is most
likely in the present case. This is also because the
carbocation II is of high energy and thus less likely to form.
To further extend the scope of this reaction we considered
using acrylic esters 4 (Scheme 3) derived from the Baylis–
Hillman reaction.19 Thus, a series of such esters were
reacted with the present reagent system to form the
corresponding diols 5 which could be readily dehydrated
via their mesylates into the corresponding b-nitro acrylates
6 in fair to good yields (Table 2). b-Nitro acrylates 6 were
found be exclusively the Z-isomers (entries 6a–c and e) or
with the Z-isomer as the major product (entry 6d). The
geometry of the olefinic bond was established on the basis of
nOe experiments in which irradiation of either of the allylic
proton or the olefinic proton led to the enhancement of the
other peak. The corresponding acetates 7 were also reacted
with NaNO2–CAN, however, they gave almost 1:1 mixture
of nitro olefin 8 and nitro alcohol 9 in modest yields
(Table 3). Compound 8 was obtained as a mixture of E- and
Z-isomers in which either the Z-isomer was the major
product (entries a, c, f and g, Table 3) or the only product
(entries b, d and e, Table 3). Once again the geometry of the
Table 3.
Entry
Yield (%)
7 R
Ph
o-Cl
m-Cl
p-Cl
o-NO2
C2H5
C3H7
8 (E:Z)
9
a
b
c
d
e
f
49 (1:6)
45 (0:1)
46 (1:4)
50 (0:1)
43 (0:1)
48 (1:6)
40 (1:6)
31
53
51
47
50
50
58
g
Scheme 2.

K. Jayakanthan et al. / Tetrahedron 60 (2004) 397–403
399
1. Experimental
1.1. General
Infrared spectra were recorded on Bruker FT/IR Vector 22
spectrophotometer. 1H and 13C NMR spectra were recorded
on JEOL LA-400 (400 and 100 MHz, respectively)
spectrometer in solutions of CDCl3 using tetramethylsilane
as the internal standard. The mass spectra were recorded on
a Micromass Quattro II Triple Quadrupole Mass Spec-
trometer. Elemental analyses were carried out on a
Thermoquest CE-instruments EA-1110 C, H, N, S analyser.
Column chromatography was performed on silicagel (100–
200 mesh) and thin layer chromatography (TLC) was
performed on Silica gel plates made by using grade G silica
gel obtained from s.d.fine-chem Ltd, Mumbai. Melting
points were determined using a Fischer–John melting point
apparatus. All solvents and common reagents were purified
by established procedures.21 Ceric ammonium nitrate and
sodium nitrite were dried at 80 8C/0.2 mm for 3 h.
Scheme 4.
Table 4.
Entry
6 R
10 Yield (%)
a
b
c
Ph
m-Cl–Ph
p-Cl–Ph
90
81
76
1.2. General procedure for the nitration of acrylic esters
To a stirred solution of an acrylic ester (1 mmol) in
anhydrous CH3CN (5 mL) were added CAN (1.64 g,
3 mmol) and NaNO2 (207 mg, 3 mmol) at 0 8C under
nitrogen. The reaction mixture was vigorously stirred for
24 h at rt, diluted with water and extracted with ethyl
acetate. The organic layer was washed sequentially with
saturated solution of NaHCO3, brine and dried over
anhydrous Na2SO4. The residue obtained after evaporation
of the solvent was purified by column chromatography to
get the nitro alcohols.
double bond in 8 was established using nOe experiments
(vide supra) after chromatographically separating the
mixture of 8 and 9.
Compounds 6a–e appear to be very interesting since they
possess a good leaving group as a mesylate along with the
b-nitro acrylate system. In our preliminary experiments, we
have reacted some of these compounds 6a–c (with R¼aryl)
with NaN3, and it was interesting to find that these
compounds led to the formation of the corresponding
cyano derivatives 10a–c20 (Scheme 4, Table 4) in a highly
stereoselective manner. The geometry of the double bond
1.3. General procedure for the dehydration of nitro
alcohols
1
was established by comparison with the reported H NMR
spectral data20 for these compounds and also by the X-ray
analysis of 10a (R¼Ph). A tentative mechanism for the
formation of 10 could be written as shown in Scheme 4.
When R is an aliphatic moiety, the reaction was found to be
unclean and hence was not further pursued. Although, these
compounds 10a–c can be readily obtained by the classical
Knovenagel type condensation of cyanoacetic esters with
aldehydes, the mechanism through which these are obtained
in the present cases is interesting.
To a stirred solution of a nitro alcohol (1 mmol) in dry
CH2Cl2 ( mL) were added MeSO2Cl (0.2 mL, 3 mmol),
Et3N (0.4 mL, 3 mmol) at 220 8C in succession. After the
reaction was over (TLC monitoring), it was poured into ice-
cold water and extracted with CH2Cl2, washed with water,
brine and then dried over anhydrous Na2SO4. Evaporation
of the solvent gave a crude product, which was purified by
column chromatography.
1.4. General procedure for the conversion of mesylates
into cyano derivatives
In summary, we have demonstrated that NaNO2–CAN is an
excellent reagent to obtain b-nitro acrylic esters from a
variety of acrylic esters in good to excellent yields. We have
performed this preparation on scales ranging from 1 to
50 mmol without any change in the yields. In view of the
fact that such nitro acrylates have already found use in
organic synthesis2–6 and since our method of preparation is
very simple and high yielding, this methodology should find
widespread application in organic synthesis. Some of these
products, derived from the Baylis–Hillman based acrylic
esters 6, which contain a mesylate group also, lead to
2-cyano-3-substituted acrylic esters in excellent yields.
Further work to explore the potential of compounds 6 and 8
and also to explore the potential of NaNO2–CAN reagent
system with other a,b-unsaturated compounds is in
progress.
To a stirred solution of a mesylate (0.15 mmol) in dry DMF
(1 mL) at 0 8C was added NaN3 (12 mg, 0.17 mmol) under
nitrogen. After disappearance of the mesylate (TLC
monitoring after 5 min), the reaction mixture was poured
into ice water, extracted with diethyl ether followed by
washing with brine, drying over anhydrous Na2SO4, and
then concentrated in vacuum. The crude solid residue was
purified by column chromatography.
1.4.1. Methyl 2-hydroxy-3-nitro-butyrate (2b). Pale
1
yellow oil; H NMR (400 MHz, CDCl3) d 5.47–5.16 (m,
2H), 3.85 (br s, 3H), 3.84 (br s, 1H), 1.21 and 1.20 (2d,
J¼6.6 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 163.2,
163.1, 87.8, 87.7, 87.1, 87.0, 53.9, 53.8, 11.9, 11.8; nmax

400
K. Jayakanthan et al. / Tetrahedron 60 (2004) 397–403
(neat film) 3487 (br), 1736, 1555, 1367 cm21. ESMS: m/z
186 [MþNa]þ. Anal. calcd for C5H9NO5: C, 36.81; H, 5.56;
N, 8.59%. Found: C, 36.77; H, 5.58; N, 8.57%.
C11H11NO4: C, 59.73; H, 5.01; N, 6.33%. Found: C, 59.81;
H, 5.03; N, 6.24%.
1.4.10. Methyl 3-anisyl-3-nitro-acrylate (3f). (1:1, E:Z
isomers). Yellow oil; 1H NMR (400 MHz, CDCl3) d 7.49–
6.90 (m, 5H), 3.89 (2s, 3H), 3.84 (2s, 3H); 13C NMR
(100 MHz, CDCl3) d 162.8, 160.0, 137.6, 136.9, 132.9,
132.1, 121.1 (m), 114.9, 114.8, 114.2, 114.1, 55.5, 55.4,
53.5, 53.3; nmax (neat film) 1732, 1602, 1528 cm21. ESMS:
m/z 260 [MþNa]þ, 238 [Mþ1]þ. Anal. calcd for
C11H11NO5: C, 55.70; H, 4.67; N, 5.90%. Found: C,
55.62; H, 4.70; N, 5.98%.
1.4.2. Methyl 2-hydroxy-2-methyl-3-nitro-propionate
1
(2c). Pale yellow oil; H NMR (400 MHz, CDCl3) d 4.80
(d, J¼13.7 Hz, 1H), 4.52 (d, J¼13.7 Hz, 1H), 3.81 (s, 3H),
1.40 (s, 3H); 13C NMR (100 MHz, CDCl3) d 173.9, 80.9,
72.5, 53.5, 23.6; nmax (neat film) 3550 (br), 1759, 1565,
1384 cm21. ESMS: m/z 186 [MþNa]þ. Anal. calcd for
C5H9NO5: C, 36.81; H, 5.56; N, 8.59%. Found: C, 36.83; H,
5.61; N, 8.56%.
1.4.3. (E)-Ethyl 3-nitro-acrylate (3a). Yellow solid, mp
39–40 8C; 1H NMR (400 MHz, CDCl3) d 7.69 (d,
J¼13.6 Hz, 1H), 7.09 (d, J¼13.6 Hz, 1H), 4.33 (q,
J¼7.1 Hz, 2H), 1.35 (t, J¼7.1 Hz, 3H); 13C NMR
(100 MHz, CDCl3) d 162.5, 148.8, 127.6, 62.3, 13.9; nmax
(neat film) 1730, 1541, 1356 cm21. ESMS: m/z: 145 [Mþ],
116 [Mþ229]. Anal. calcd for C5H7NO4: C, 41.38; H, 4.86;
N, 9.65%. Found: C, 41.44; H, 4.79; N, 9.54%.
1.4.11. Methyl 2,3-dihydroxy-2-nitromethyl-3-phenyl-
propionate (5a). Viscous oil; 1H NMR (400 MHz,
CDCl3) d 7.35–7.24 (m, 5H), 5.46 (s, 1H), 5.33–4.77 (m,
2H), 3.87 (s, 3H), 3.70 (br s, 2H); 13C NMR (100 MHz,
CDCl3) d 171.0, 141.3, 136.7, 128.3, 126.7, 78.8, 75.4, 71.1,
53.2; nmax (neat film) 3493 (br), 1743, 1561, 1379 cm21
.
ESMS: m/z 278 [MþNa]þ. Anal. calcd for C11H13NO6: C,
51.77; H, 5.13; N, 5.49%. Found: C, 51.69; H, 5.09; N,
5.47%.
1.4.4. (E)-Methyl 3-nitro-but-2-enoate (3b). Yellow oil;
1H NMR (400 MHz, CDCl3) d 6.90 (q, J¼1.7 Hz, 1H), 3.89
(s, 3H), 2.11 (d, J¼1.7 Hz, 3H); 13C NMR (100 MHz,
CDCl3) d 166.6, 140.6, 135.9, 53.1, 17.5; nmax (neat film)
1734, 1526, 1349 cm21. ESMS: m/z 145 [Mþ]. Anal. calcd
for C5H7NO4: C, 41.38; H, 4.86; N, 9.65%. Found: C, 41.53;
H, 4.85; N, 9.63%.
1.4.12. Methyl 3-(3-chloro-phenyl)-2,3-dihydroxy-2-
nitromethyl-propionate (5b). Colourless solid, mp 122–
123 8C; 1H NMR (400 MHz, CDCl3) d 7.35–7.13 (m, 4H),
5.47 and 5.31 (2s, 1H), 5.08–4.37 (m, 2H), 3.87 and 3.75
(2s, 3H), 3.14 (br s, 2H); 13C NMR (100 MHz, CDCl3) d
171.6, 170.9, 139.20, 139.1, 134.5, 134.3, 129.7, 129.6,
129.2, 129.0, 127.4, 127.1, 125.4, 125.0, 78.7, 78.6, 78.3,
78.1, 75.8, 74.9, 53.8, 53.2; nmax (neat film) 3503 (br), 1750,
1566, 1382 cm21. ESMS: m/z 312 [MþNa]þ. Anal. calcd
for C11H12ClNO6: C, 45.61; H, 4.18; N, 4.84%. Found: C,
45.57; H, 4.19; N, 4.81%.
1.4.5. (E)-Methyl 2-methyl-3-nitro-acrylate (3c). Yellow
oil; 1H NMR (400 MHz, CDCl3) d 7.08 (q, J¼1.2 Hz, 1H),
3.84 (s, 3H), 2.60 (d, J¼1.2 Hz, 3H); 13C NMR (100 MHz,
CDCl3) d 164.6, 160.1, 120.9, 52.6, 14.0; nmax (neat film)
1731, 1540, 1368 cm21. ESMS: m/z 168 [MþNa]þ. Anal.
calcd for C5H7NO4: C, 41.38; H, 4.86; N, 9.65%. Found: C,
41.36; H, 4.90; N, 9.54%.
1.4.13. Methyl 3-(4-chloro-phenyl)-2,3-dihydroxy-2-
nitromethyl-propionate (5c). Colourless solid, mp 132–
133 8C; 1H NMR (400 MHz, CDCl3) d 7.34–7.29 (m, 4H),
5.50 and 5.29 (2s, 1H), 4.99–4.30 (m, 2H), 3.88 and 3.86
(2s, 3H), 3.73 (br s, 1H), 3.57 (br s, 1H); 13C NMR
(100 MHz, CDCl3) d 171.6, 171.0, 136.7, 136.4, 134.1,
134.0, 128.7, 128.5, 128.1, 128.0, 79.1, 78.9, 76.6, 75.5,
74.6, 72.8, 53.1, 52.7; nmax (neat film) 3522 (br), 1753,
1566, 1388 cm21. ESMS: m/z 312 [MþNa]þ. Anal. calcd
for C11H12ClNO6: C, 45.61; H, 4.18; N, 4.84%. Found: C,
45.59; H, 4.17; N, 4.81%.
1.4.6. (E)-Ethyl 3-nitro-3-phenyl-acrylate (3d). Mixture
1
with (Z)-3d. Yellow solid; H NMR (400 MHz, CDCl3) d
7.53–7.42 (m, 6H), 4.38 (q, J¼7.1 Hz, 2H), 1.35 (t,
J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 159.2,
136.5, 132.1, 130.4, 129.7, 129.3, 63.0, 14.0.
1
1.4.7. (Z)-3d. H NMR (400 MHz, CDCl3) d 8.08 (s, 1H),
7.53–7.42 (m, 5H), 4.44 (q, J¼7.1 Hz, 2H), 1.37 (t,
J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 161.1,
140.1, 132.9, 132.3, 129.3, 128.2, 63.1, 13.7; nmax (neat
film) 1732, 1644, 1535, 1321 cm21. ESMS: m/z 244
[MþNa]þ. Anal. calcd for C11H11NO4: C, 59.73; H, 5.01;
N, 6.33%. Found: C, 59.71; H, 5.04; N, 6.24%.
1.4.14. Methyl 2,3-dihydroxy-2-nitromethyl-pentanoate
1
(5d). Colourless solid, mp 96–97 8C; H NMR (400 MHz,
CDCl3) d 4.95–4.59 (2dd, J¼13.9 Hz, 2H), 4.11 (br d,
J¼13.1 Hz, 1H), 3.81 and 3.80 (2s, 3H), 3.50 (m, 1H), 2.70
(br s, 1H), 1.59–1.36 (m, 1H), 1.22 (m,1H), 0.95–0.90 (2t,
J¼7.3 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 172.2,
172.0, 79.2, 78.6, 78.3, 78.2, 75.8, 74.7, 53.6, 53.5, 24.0,
23.6, 10.1, 9.9; nmax (neat film) 3498 (br), 1743, 1561,
1381 cm21. ESMS: m/z 230 [MþNa]þ. Anal. calcd for
C7H13NO6: C, 40.58; H, 6.32; N, 6.76%. Found: C, 40.56;
H, 6.28; N, 6.72%.
1.4.8. (E)-Methyl 3-nitro-3-p-tolyl-acrylate (3e). Mixture
1
with (Z)-3e. Yellow solid; H NMR (400 MHz, CDCl3) d
8.03 (s, 1H), 7.36–7.22 (m, 4H), 3.94 (s, 3H), 2.37 (s, 3H);
13C NMR (100 MHz, CDCl3) d 161.7, 143.6, 140.5, 136.9,
130.4, 129.9, 125.8, 53.4, 21.4.
1
1.4.9. (Z)-3e. H NMR (400 MHz, CDCl3) d 7.49 (s, 1H),
7.29–7.17 (m, 4H), 3.87 (s, 3H), 2.35 (s, 3H); 13C NMR
(100 MHz, CDCl3) d 159.6, 143.2, 138.7, 132.9, 129.9,
129.7, 125.7, 53.2, 21.3; nmax (neat film) 1740, 1546,
1362 cm21. ESMS: m/z 244 [MþNa]þ. Anal. calcd for
1.4.15. Methyl 2,3-dihydroxy-2-nitromethyl-hexanoate
1
(5e). Colourless solid, mp 84–86 8C; H NMR (400 MHz,
CDCl3) d 5.02–4.66 (2d, J¼13.9 Hz, 2H), 3.94 (br s, 1H),
3.92 (s, 3H), 3.68 (t, J¼8.4 Hz, 1H), 2.24 (br d, J¼8.5 Hz,

K. Jayakanthan et al. / Tetrahedron 60 (2004) 397–403
401
1H), 1.63–1.51 (m, 2H), 1.39–1.26 (m, 2H), 0.94 (t,
J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 172.2, 78.7,
78.1, 74.3, 53.8, 33.2, 18.9, 13.6; nmax (neat film) 3484 (br),
1740, 1559, 1372 cm21. ESMS: m/z 244 [MþNa]þ. Anal.
calcd for C8H15NO6: C, 43.44; H, 6.83; N, 6.33%. Found: C,
43.42; H, 6.79; N, 6.32%.
1.4.22. (E)-Methyl 2-(acetoxy-phenyl-methyl)-3-nitro-
1
acrylate (8a). Mixture with (Z)-8a. Pale yellow solid; H
NMR (400 MHz, CDCl3) d 7.64 (s, 1H), 7.02 (s, 1H), 7.42–
7.34 (m, 5H), 3.76 (s, 3H), 2.07 (s, 3H); 13C NMR
(100 MHz, CDCl3) d 169.4, 163.2, 142.8, 135.1, 132.8,
128.8, 128.5, 127.3, 70.5, 53.1, 20.4.
1
1.4.16. (Z)-Methyl 2-(methanesulfonyloxy-phenyl-
methyl)-3-nitro-acrylate (6a). Yellow oil; 1H NMR
(400 MHz, CDCl3) d 7.44–7.34 (m, 5H), 7.16 (d,
J¼1.7 Hz, 1H), 6.40 (d, J¼1.7 Hz, 1H), 3.70 (s, 3H), 2.82
(s, 3H); 13C NMR (100 MHz, CDCl3) d 162.5, 139.2, 138.1,
132.3, 130.5, 129.2, 127.6, 78.6, 53.2, 39.0; nmax (neat film)
1743, 1543, 1363 cm21. ESMS: m/z 338 [MþNa]þ. Anal.
calcd for C12H13NO7S: C, 45.71; H, 4.16; N, 4.44; S,
10.17%. Found: C, 45.85; H, 4.02; N, 4.32; S, 10.12%.
1.4.23. (Z)-8a. H NMR (400 MHz, CDCl3) d 7.42–7.34
(m, 5H), 7.05 (d, J¼1.7 Hz, 1H), 6.62 (d, J¼1.7 Hz, 1H),
3.72 (s, 3H), 2.13 (s, 3H); 13C NMR (100 MHz, CDCl3) d
168.6, 163.3, 141.5, 137.2, 134.0, 129.6, 128.9, 127.5, 72.3,
53.1, 20.6; nmax (neat film) 1747, 1359, 1359 cm21. ESMS:
m/z 302 [MþNa]þ. Anal. calcd for C13H13NO6: C, 55.92; H,
4.69; N, 5.02%. Found: C, 55.86; H, 4.70; N, 5.06%.
1.4.24. (Z)-Methyl-2-[acetoxy-(2-chloro-phenyl)-
methyl]-3-nitro-acrylate (8b). Yellow solid, mp 96–
97 8C; H NMR (400 MHz, CDCl3) d 7.44–7.21 (m, 4H),
6.98 (d, J¼1.4 Hz, 1H), 6.96 (d, J¼1.4 Hz, 1H), 3.74 (s,
3H), 2.13 (s, 3H); 13C NMR (100 MHz, CDCl3) d 168.4,
162.9, 140.1, 137.9, 133.0, 132.0, 130.7, 129.9, 128.6,
127.4, 69.0, 53.3, 20.4; nmax (neat film) 1750, 1538, 1355
cm21. ESMS: m/z 336 [MþNa]þ. Anal. calcd for
C13H12NO6Cl: C, 49.78; H, 3.86; N, 4.47%. Found: C,
49.81; H, 3.88; N, 4.43%.
1
1.4.17. (Z)-Methyl 2-[(3-chloro-phenyl)-methanesul-
fonyloxy-methyl]-3-nitro-acrylate (6b). Yellow oil; 1H
NMR (400 MHz, CDCl3) d 7.46–7.31 (m, 4H), 7.15 (d,
J¼1.7 Hz, 1H), 6.37 (d, J¼1.7 Hz, 1H), 3.75 (s, 3H), 2.93
(s, 3H); 13C NMR (100 MHz, CDCl3) d 162.4, 138.6, 138.5,
135.3, 134.5, 130.8, 130.7, 127.7, 125.8, 77.5, 53.6, 39.4;
nmax (neat film) 1743, 1545, 1363 cm21. ESMS: m/z 372
[MþNa]þ. Anal. calcd for C12H12ClNO7S: C, 41.21; H,
3.46; N, 4.00; S, 9.17%. Found: C, 41.10; H, 3.41; N, 4.07;
S, 9.19%.
1.4.25. (E)-Methyl-2-[acetoxy-(3-chloro-phenyl)-
methyl]-3-nitro-acrylate (8c). Mixture with (Z)-8c. Yellow
oil; 1H NMR (400 MHz, CDCl3) d 7.67 (s, 1H), 7.53–7.26
(m, 4H), 7.00 (s, 1H), 3.79 (s, 3H), 2.09 (s, 3H); 13C NMR
(100 MHz, CDCl3) d 169.3, 163.0, 143.7, 137.2, 134.4,
132.4, 129.8, 128.9, 127.3, 125.4, 69.4, 53.2, 20.3.
1.4.18. (Z)-Methyl 2-[(4-chloro-phenyl)-methanesul-
fonyloxy-methyl]-3-nitro-acrylate (6c). Yellow oil; 1H
NMR (400 MHz, CDCl3) d 7.46–7.23 (m, 4H), 7.15 (d,
J¼1.5 Hz, 1H), 6.39 (br s, 1H), 3.74 (s, 3H), 2.89 (s, 3H);
13C NMRd 162.4, 138.8, 138.3, 136.8, 131.0, 129.7, 129.2,
1
77.7, 53.6, 39.4; nmax (neat film) 1750, 1551, 1373 cm21
.
1.4.26. (Z)-8c. H NMR (400 MHz, CDCl3) d 7.53–7.26
ESMS: m/z 372 [MþNa]þ. Anal. calcd for C12H12ClNO7S:
C, 41.21; H, 3.46; N, 4.00; S, 9.17%. Found: C, 41.29; H,
3.42; N, 3.97; S, 9.12%.
(m, 4H), 7.09 (s, 1H), 6.58 (s, 1H), 3.74 (s, 3H), 2.16 (s, 3H);
13C NMR (100 MHz, CDCl3) d 168.5, 162.9, 143.4, 140.5,
137.5, 136.0, 134.8, 130.2, 127.5, 125.7, 71.6, 53.2, 20.6;
nmax (neat film) 1748, 1540, 1360 cm21. ESMS: m/z 336
[MþNa]þ. Anal. calcd for C13H12NO6Cl: C, 49.78; H, 3.86;
N, 4.47%. Found: C, 49.74; H, 3.82; N, 4.49%.
1.4.19. (E)-Methyl 3-methanesulfonyloxy-2-nitromethyl-
ene-pentanoate (6d). Mixture with (Z)-6d. Colourless oil;
1H NMR (400 MHz, CDCl3) d 7.56 (s, 1H), 5.82 (m, 1H),
3.87 (s, 3H), 3.02 (s, 3H), 1.99–1.88 (m, 2H), 1.06 (t,
J¼7.4 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 162.9,
143.2, 136.4, 71.4, 53.2, 37.9, 28.1, 10.1.
1.4.27. (Z)-Methyl-2-[acetoxy-(4-chloro-phenyl)-
methyl]-3-nitro-acrylate (8d). Yellow oil; 1H NMR
(400 MHz, CDCl3) d 7.92–7.27 (m, 4H), 7.08 (d,
J¼1.4 Hz, 1H), 6.58 (d, J¼1.5 Hz, 1H), 3.74 (s, 3H), 2.14
(s, 3H); 13C NMR (100 MHz, CDCl3) d 168.4, 163.0, 140.8,
137.3, 135.7, 132.6, 129.2, 129.0, 71.7, 53.3, 20.6; nmax
(neat film) 1747, 1539, 1360 cm21. ESMS: m/z 336
[MþNa]þ. Anal. calcd for C13H12NO6Cl: C, 49.78; H,
3.86; N, 4.47%. Found: C, 49.82; H, 3.85; N, 4.46%.
1.4.20. (Z)-6d. 1H NMR (400 MHz, CDCl3) d 7.13 (s, 1H),
5.26 (t, J¼6.2 Hz, 1H), 3.92 (s, 3H), 3.10 (s, 3H), 1.99–1.88
(m, 2H), 1.04 (t, J¼7.4 Hz, 3H); 13C NMR (100 MHz,
CDCl3) d 162.9, 139.9, 137.9, 78.4, 53.6, 38.9, 27.1, 8.9;
nmax (neat film) 1742, 1541, 1357 cm21. ESMS: m/z 290
[MþNa]þ. Anal. calcd for C8H13NO7S: C; 35.95; H, 4.90;
N, 5.24; S, 12.00%. Found: C, 36.04; H, 4.94; N, 5.19; S,
12.17%.
1.4.28. (Z)-Methyl-2-[acetoxy-(2-nitro-phenyl)-methyl]-
3-nitro-acrylate (8e). Yellow oil; 1H NMR (400 MHz,
CDCl3) d 8.09–7.58 (m, 4H), 7.25 (d, J¼1.4 Hz, 1H), 7.12
(d, J¼1.4 Hz, 1H), 3.81 (s, 3H), 2.15 (s, 3H); 13C NMR
(100 MHz, CDCl3) d 168.4, 162.8, 147.8, 139.9, 138.3,
134.1, 130.4, 130.2, 128.9, 125.1, 67.6, 53.4, 20.5; nmax
(neat film) 1745, 1533, 1353 cm21. ESMS: m/z 347
[MþNa]þ. Anal. calcd for C13H12N2O8: C, 48.16; H,
3.73; N, 8.64%. Found: C, 48.12; H, 3.76; N, 8.63%.
1.4.21. (Z)-Methyl 3-methanesulfonyloxy-2-nitromethyl-
1
ene-hexanoate (6e). Colourless oil; H NMR (400 MHz,
CDCl3) d 7.13 (d, J¼1.0 Hz, 1H), 5.31 (br t, J¼6.5 Hz, 1H),
3.92 (s, 3H), 3.10 (s, 3H), 1.86 (m, 2H), 1.48 (m, 2H), 0.98
(t, J¼7.3 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 162.9,
140.2, 137.9, 77.1, 53.6, 38.9, 35.8, 18.0, 13.2; nmax (neat
film) 1744, 1543, 1359 cm21. ESMS: m/z 304 [MþNa]þ.
Anal. calcd for C9H15NO7S: C, 38.43; H, 5.38; N, 4.98; S,
11.40%. Found: C, 38.37; H, 5.32; N, 5.01; S, 11.38%.
1.4.29. (E)-Methyl-3-acetoxy-2-nitromethylene-pentano-
ate (8f). Mixture with (Z)-8f. Yellow oil; 1H NMR

402
K. Jayakanthan et al. / Tetrahedron 60 (2004) 397–403
(400 MHz, CDCl3) d 7.49 (s, 1H), 5.81 (dd, J¼9.1, 4.8 Hz,
1H), 3.86, (s, 3H), 2.03 (s, 3H), 1.92–1.77 (m, 2H), 1.00 (t,
J¼7.4 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 170.3,
163.6, 142.7, 135.9, 70.9, 53.3, 26.5, 20.5, 10.3.
135.6, 135.5, 134.4, 134.2, 129.7, 129.6 (2s), 129.4, 128.1,
127.7, 126.2, 125.7, 78.1, 77.8, 76.9, 77.4, 75.1, 74.9, 53.9,
53.8, 20.7, 20.5; nmax (neat film) 3498 (br), 1760, 1568,
1378 cm21. ESMS: m/z 354 [MþNa]þ. Anal. calcd for
C13H14ClNO7: C, 47.07; H, 4.25; N, 4.22%. Found: C,
47.13; H, 4.30; N, 4.27%.
1.4.30. (Z)-8f. 1H NMR (400 MHz, CDCl3) d 7.01 (d,
J¼1.2 Hz, 1H), 5.47 (td, J¼6.3, 1.0 Hz, 1H), 3.90 (s, 3H),
2.13 (s, 3H), 1.92–1.77 (m, 2H), 0.97 (t, J¼7.4 Hz, 3H); 13C
NMR (100 MHz, CDCl3) d 169.5, 163.7, 142.0, 137.0, 71.9,
53.4, 26.0, 20.7, 9.1; nmax (neat film) 1743, 1535,
1358 cm21. ESMS: m/z 254 [MþNa]þ. Anal. calcd for
C9H13NO6: C, 46.76; H, 5.67; N, 6.06%. Found: C, 46.82;
H, 5.71; N, 5.98%.
1.4.36. Methyl-3-acetoxy-3-(4-chlorophenyl)-2-hydroxy-
2-nitromethyl-propionate (9d). Colourless solid, mp
82–84 8C; 1H NMR (400 MHz, CDCl3) d 7.35–7.26
(m, 4H), 5.89 and 5.84 (2s, 1H), 4.98–4.22 (2dd, J¼13.9,
13.7 Hz, 2H), 3.87 and 3.81 (2s, 3H), 2.14 and 2.07 (2s,
3H); 13C NMR (100 MHz, CDCl3) d 170.9, 170.4, 169.4,
168.9, 135.4, 135.2, 132.2, 132.1, 129.5, 129.0, 128.7,
128.6, 78.2, 77.8, 77.4, 76.9, 75.1, 75.0, 53.9 (2s), 20.7,
20.5; nmax (neat film) 3506, 1761, 1566, 1378 cm21. ESMS:
m/z 354 [MþNa]þ. Anal. calcd for C13H14ClNO7: C,
47.07; H, 4.25; N, 4.22%. Found: C, 47.13; H, 4.17; N,
4.18%.
1.4.31. (E)-Methyl-3-acetoxy-2-nitromethylene-hexano-
ate (8g). Mixture with (Z)-8g. Yellow oil; 1H NMR
(400 MHz, CDCl3) d 7.48 (s, 1H), 5.90–5.87 (dd, J¼9.5,
3.9 Hz,1H), 3.86 (s, 3H), 2.02 (s, 3H), 1.79 (q, J¼6.6 Hz,
2H), 1.48–1.34 (m, 2H), 0.97 (t, J¼6.6 Hz, 3H); 13C NMR
(100 MHz, CDCl3) d 170.1, 163.5, 142.4, 136.2, 69.3, 53.1,
34.9, 20.3, 18.9, 13.3.
1.4.37. Methyl-3-acetoxy-2-hydroxy-2-nitromethyl-3-(2-
nitrophenyl)-propionate (9e). Yellow solid, mp 102–
103 8C; 1H NMR (400 MHz, CDCl3) d 7.98–7.51 (m, 4H),
6.88 and 6.57 (2s, 1H), 5.32–4.19 (2dd, J¼13.9, 13.8 Hz,
2H), 3.96 and 3.85 (2s, 3H), 2.16 and 2.02 (2s, 3H); 13C
NMR (100 MHz, CDCl3) d 171.2, 170.6, 168.8 (2s), 149.3,
148.7, 133.5, 132.9, 131.3, 130.2, 130.1, 130.0, 129.1,
128.5, 124.7, 124.3, 78.2, 77.3, 77.2, 76.3, 69.5, 69.4, 54.4,
54.3, 20.7, 20.4; nmax (neat film) 3500, 1760, 1566,
1535 cm21. ESMS: m/z 365 [MþNa]þ. Anal. calcd for
C13H14N2O9: C, 45.62; H, 4.12; N, 8.18%. Found: C, 45.94;
H, 4.08; N, 8.13%.
1.4.32. (Z)-8g. 1H NMR (400 MHz, CDCl3) d 7.03 (s, 1H),
5.51 (t, J¼6.3 Hz, 1H), 3.90 (s, 3H), 2.12 (s, 3H), 1.77 (q,
J¼6.6 Hz, 2H), 1.48–1.34 (m, 2H), 0.95 (t, J¼6.6 Hz, 3H);
13C NMR (100 MHz, CDCl3) d 169.4, 163.6, 142.2, 136.7,
70.6, 53.2, 34.7, 20.5, 18.0, 13.4; nmax (neat film) 1744,
1538, 1363 cm21. ESMS: m/z 268 [MþNa]þ. Anal. calcd
for C10H15NO6: C, 48.98; H, 6.17; N, 5.71%. Found: C,
48.92; H, 6.21; N, 5.68%.
1.4.33. Methyl 3-acetoxyl-2-hydroxy-2-nitromethyl-3-
phenyl-propionate (9a). Yellow solid, mp 98–99 8C;
1H NMR (400 MHz, CDCl3) d 7.30–7.20 (m, 5H),
5.85 and 5.81 (2s, 1H), 4.91–4.15 (2dd, J¼13.9 Hz,
2H), 3.77 and 3.71 (2s, 3H), 2.05 and 1.98 (2s, 3H); 13C
NMR (100 MHz, CDCl3) d 171.2, 170.5, 169.5, 168.9,
133.6, 133.5, 129.3, 129.2, 128.5, 128.3, 128.0, 127.5,
78.2, 77.9, 77.3, 77.0, 75.8, 75.6, 53.8, 53.7, 20.7, 20.5;
1.4.38. Methyl-3-acetoxy-2-hydroxy-2-nitromethyl-pen-
tanoate (9f). Pale yellow oil; 1H NMR (400 MHz,
CDCl3) d 5.05 (m, 1H), 4.67 (m, 2H), 3.90 and 3.86
(2s, 3H), 2.15 and 2.10 (2s, 3H), 1.65 (m, 2H), 1.17 and
1.53 (2t, J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3)
d 171.5, 171.4, 170.5, 170.0, 78.1, 77.6, 76.8, 76.7,
75.2, 75.1, 54.0, 53.6, 21.9, 21.8, 20.5, 20.4, 9.7 (2s);
nmax (neat film) 3490, 1746, 1562, 1376 cm21. ESMS:
m/z 272 [MþNa]þ. Anal. calcd for C9H15NO7: C, 43.38;
H, 6.07; N, 5.62%. Found: C, 43.16; H, 6.13; N, 5.58%.
nmax (neat film) 3493 (br), 1755, 1563, 1377 cm21
.
ESMS: m/z 320 [MþNa]þ. Anal. calcd for C13H15NO7:
C, 52.53; H, 5.09; N, 4.71%. Found: C, 52.35; H, 5.13;
N, 4.68%.
1.4.34. Methyl-3-acetoxy-3-(2-chlorophenyl)-2-hydroxy-
2-nitromethyl-propionate (9b). Colourless solid, mp 70–
71 8C; H NMR (400 MHz, CDCl3) d 8.17–7.25 (m, 4H),
1.4.39. Methyl-3-acetoxy-2-hydroxy-2-nitromethyl-hex-
1
anoate (9g). Pale yellow oil; H NMR (400 MHz, CDCl3)
1
d 5.13 (m, 1H), 4.90–4.62 (2dd, J¼13.9 Hz, 2H), 3.89 and
3.86 (2s, 3H), 2.13 and 2.08 (2s, 3H), 1.71–1.21 (m, 4H),
0.93 and 0.88 (2t, J¼13.9 Hz, 3H); 13C NMR (100 MHz,
CDCl3) d 171.5, 171.4, 170.4, 169.9, 78.0, 77.7, 76.8, 76.7,
73.6, 73.5, 53.9, 53.5, 30.7, 30.5, 20.5, 20.4, 18.5, 18.4,
6.48 and 6.46 (2s, 1H), 5.28–4.12 (m, 2H), 3.93 and 3.83
(2s, 3H), 2.12 and 2.05 (2s, 3H); 13C NMR (100 MHz,
CDCl3) d 171.2, 170.5, 169.2, 168.7, 143.1, 139.1, 133.1,
133.0, 131.7, 131.5, 130.6, 130.4, 129.9, 129.3, 127.3,
126.9, 77.9, 77.4, 71.6, 71.4, 53.9, 52.2, 38.2, 31.5, 20.7,
20.5; nmax (neat film) 3496, 1748, 1563, 1375 cm21. ESMS:
m/z 354 [MþNa]þ. Anal. calcd for C13H14ClNO7: C,
47.07; H, 4.25; N, 4.22%. Found: C, 47.13; H, 4.14; N,
4.17%.
13.5, 13.4; nmax (neat film) 3502, 1747, 1563, 1377 cm21
.
ESMS: m/z 286 [MþNa]þ. Anal. calcd for C10H17NO7: C,
45.63; H, 6.51; N, 5.32%. Found: C, 45.53; H, 6.49; N,
5.28%.
1.4.35. Methyl-3-acetoxy-3-(3-chlorophenyl)-2-hydroxy-
2-nitromethyl-propionate (9c). Colourless solid, mp 78–
79 8C; H NMR (400 MHz, CDCl3) d 7.42–7.18 (m, 4H),
Acknowledgements
1
5.88 and 5.84 (2s, 1H), 4.98–4.25 (2dd, J¼13.7, 13.8 Hz,
2H), 3.87 and 3.82 (2s, 3H), 2.16 and 2.08 (2s, 3H); 13C
NMR (100 MHz, CDCl3) d 170.9, 170.3, 169.4, 168.9,
We thank the Council of Scientific and Industrial Research,
New Delhi for financial assistance through a project ‘CSIR
sanction No. 1 (1544)/98-EMR-II’.

K. Jayakanthan et al. / Tetrahedron 60 (2004) 397–403
403
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