One-pot synthesis of heterocyclic compounds containing highly polarized double bond

Article abstract of DOI:10.1007/s00706-015-1529-1

Anionic adduct derived from malononitrile and heterocumulenes attacks on aziridines or oxiranes in regioselective manner to afford corresponding heterocycles containing highly polarized double bond. This transformation is carried out using Li₂C

Full text of DOI:10.1007/s00706-015-1529-1

Monatsh Chem
DOI 10.1007/s00706-015-1529-1
ORIGINAL PAPER
One-pot synthesis of heterocyclic compounds containing highly
polarized double bond
Alireza Samzadeh-Kermani1
Received: 14 April 2015 / Accepted: 29 June 2015
Ó Springer-Verlag Wien 2015
Abstract Anionic adduct derived from malononitrile and
heterocumulenes attacks on aziridines or oxiranes in
regioselective manner to afford corresponding heterocycles
containing highly polarized double bond. This transfor-
mation is carried out using Li2CO3 at 25–60 °C in DMF.
Graphical abstract
polarized structure of the double bond is discernible by 13
C
NMR and measurement of the barriers to rotation about the
C–C double bonds [11–16].
In continuation of our studies featuring synthesis of
heterocyclic compounds [17–19], we have examined effi-
ciency of malononitrile, heterocumulenes, and oxiranes or
aziridines.
Results and discussion
In initial attempt, a solution of malononitrile (1, 1 mmol)
and phenyl isothiocyanate (2a, 1 mmol) containing pro-
pene oxide (3a, 1.5 mmol) treated with Et3N (1 mmol) in
toluene at 25 °C for 18 h. No cyclization occurred and
2-[(2-hydroxypropylthio)(phenylimino)methyl]malononi-
trile (4) was obtained in 87 % yield. However, by
increasing the reaction temperature to 60 °C 2-(5-methyl-
1,3-oxathiolan-2-ylidene)malononitrile (5a) was achieved
in 13 % yield. To optimize the reaction conditions, the
effects of base and solvent were considered. Li-containing
bases improved the yield likely due to better hard–hard
interaction with amine moiety (Table 1). Other solvents
such as DMF, CHCl3, MeCN, and THF were also consid-
ered and the best result was achieved in DMF. The
coupling constant of the two bridgehead hydrogens
(J = 11.8 Hz) determined the trans-structure of product.
Under the optimum conditions, a number of oxiranes
and aziridines were considered (Table 2). Alkyl substituted
oxiranes were attacked at terminal position, exclusively,
while styrene oxide afforded the benzylic-attacked product
in high yield. Cis- and trans-2,3-diphenyloxirane gave
acceptable yields. Acrylate containing oxirane also affor-
ded a good yield. Cyclohexene oxide furnished the reaction
with excellent yield, while cycloheptene oxide only gave
Keywords Heterocycles Á Oxirane Á Heterocumulenes Á
Aziridine Á One-pot synthesis
Introduction
Push–pull alkenes are substituted alkenes with electron-
donating substituent(s) on one side and of the other with
electron-withdrawing substituent(s) [1–3]. Allowance for
p-electron delocalization leads to the C–C double bond
becoming polarized and the p-order of this double bond is
reduced [4–6]. This effect is readily apparent by the
restricted rotations about the C–Don and C–Acc partial
double bonds which can be studied quantitatively by
dynamic NMR spectroscopy [7–10]. Furthermore, the
& Alireza Samzadeh-Kermani
drsamzadeh@gmail.com;
arsamzadeh@uoz.ac.ir
1
Chemistry Department, Faculty of Science, University of
Zabol, Zabol, Iran
123

A. Samzadeh-Kermani
H-atoms, together with a doublet for the methyl group. The
13C NMR spectrum of 5a exhibited 7 signals in agreement
with the proposed structure. In the 13C NMR spectrum,
polarized character of central double bond is apparent, the
deshielded position of the double bond is over 90–100 ppm
at the lower field compared to the shielded position.
A plausible mechanism is proposed in Scheme 1. It is
conceivable that the reaction starts with the formation of
the intermediate 9, followed by the addition of 3 to gen-
erate 10. Cyclization of this intermediate leads to 11, which
is converted to 5 by elimination of PhNH2.
Table 1 Optimization reaction conditions
Entry
Solvent
Base
Yield/%a
1
2
3
4
5
6
7
8
DMSO
Toluene
THF
Li2CO3
Li2CO3
Li2CO3
Li2CO3
Li2CO3
Et3N
76
–
41
43
81
20
53
75
MeCN
DMF
DMF
DMF
K2CO3
LiOH
DMF
In conclusion, we have described an efficient procedure
to syntheses of 1,3-oxathiolanes and 1,3-thiazolidines
containing highly polarized double bond. The reaction was
in the most cases regioselective and only one regioisomer
was detected in NMR analyses. In this transformation,
amine moiety served as leaving group in the presence of Li
salt.
Reaction conditions: 1 (1.0 mmol), 2a (1.0 mmol), 3a (1.5 mmol),
base (1.0 mmol), 3 cm3 solvent, 60 °C, 18 h
a
79 % of 4 was achieved using Et3N at room temperature in toluene
moderate success, likely due to the steric hindrance of the
substrate. Alkyl isothiocyanate also yields the corre-
sponding product in good yield.
To extend the scope of the transformation, tosylaziridi-
nes 6 were also considered using phenyl isothiocyanate or
CS2 (7) as the reaction partner and tosylthiazolidines 8
were synthesized in good yields (Table 3). It is worthwhile
to mention that in the presence of 7 the reaction could be
run at room temperature. The regioselectivity of these
substrates is similar with those of oxiranes, although
tosylaziridines need longer reaction times to complete the
transformation.
Experimental
Epoxides, isothiocyanates, CS2, malononitrile, bases, and
solvents were obtained from Merck. Solvents were dried
before use. N-Tosylaziridines were prepared using the lit-
erature procedures [20]. Melting points: Electrothermal-
9100 apparatus. IR Spectra: Shimadzu IR-460 spectrome-
ter. 1H and 13C NMR spectra: Bruker DRX-500 AVANCE
instrument; in CDCl3 at 500.1 and 125.7 MHz, resp; d in
ppm, J in Hz. EI-MS (70 eV): Finnigan-MAT-8430 mass
spectrometer. Elemental analyses (C, H, N) were
The structures of products were confirmed by spectro-
scopic analyses. For example, the 1H NMR spectrum of 5a
showed characteristic (AB)X spin system for the CH2-CH
Table 2 Synthesis of 1,3-oxathiolane containing highly polarized double bond
Isothiocyanate
R1
Epoxide
R2
R3
R4
Product, yield/%
2a
2b
Ph
3a
3b
3c
3d
3e
3f
CH3
H
H
H
H
H
H
H
5a, 80
5b, 83
5c, 81
5d, 84
5e, 85
5f, 87
i-Pr
ClCH2
H
CH3CH2
H
(CH3)2CHOCH2
H
CH3C(CH2)COOCH2
H
CH2CHCH2OCH2
R2, R3 = –(CH2)4–
R2, R3 = –(CH2)5–
H
3g
3h
3i
H
5g, 93
5h, 52
5i, 80a
5j, 87 (79)b
5k, 90
5l, 89
H
Ph
H
H
3j
PhOCH2
C3H7
Ph
H
H
3k
3l
H
CH3
H
Ph (cis)
Ph (trans)
H
3m
3n
Ph
H
5m, 82
5n, 86
Bn
H
Reaction conditions: 1 (1.0 mmol), 2 (1.0 mmol), 3 (1.5 mmol), Li2CO3 (1.0 mmol), 3 cm3 DMF, 60 °C, 18 h
a
The yield of benzylic-attacked product
b
2b was used as the isothiocyanate source
123

One-pot synthesis of heterocyclic compounds containing highly polarized double bond
5g, 5i, 5j) [6] gave satisfactory spectroscopic values and
are analog to spectroscopic data reported in literature.
Table 3 Synthesis of 1,3-thiazolidine derivatives
Aziridine
R2, R3
Product, yield/%
2-(Hexahydro-3aH-cyclohepta[d][1,3]oxathiol-2-
ylidene)malononitrile (5h, C11H12N2OS)
6a
6b
6c
6d
6e
6f
Ph, H
8a, 89 (78)a
8b, 83 (76)
8c, 86 (75)
8d, 89 (81)
8e, 52 (43)
8f, 91 (82)
Bn, H
The crude product was purified by column chromatography
(SiO2; hexane/EtOAc 4/1, Rf = 0.53) affording 0.10 g
(49 %) 5h. Colorless crystals; m.p.: 90–92 °C; IR (KBr): v
C3H7, CH3
–(CH2)4–
–(CH2)5–
4-MeO–C6H4, H
1
= 2972, 2247, 2231, 1568, 1318, 1124 cm-1; H NMR
(500 MHz, CDCl3): d = 1.54–2.28 (m, 5 CH2), 3.13–3.20
(m, CH), 3.89–3.94 (m, CH) ppm; 13C NMR (125.7 MHz,
CDCl3): d = 21.2 (CH2), 24.5 (CH2), 26.8 (CH2), 31.4
(CH2), 33.0 (CH2), 48.1 (CH), 82.6 (CH), 86.2 (C), 111.2
(CN), 113.5 (CN), 190.3 (C) ppm; EI-MS (70 eV):
m/z (%) = 220 (M?, 3), 163 (58), 149 (100), 82 (86), 64
(40), 56 (35).
Reaction conditions: 1 (1.0 mmol), 6 (1.5 mmol), 7 (3.0 mmol),
Li2CO3 (1.0 mmol), 3 cm3 DMF, 25 °C, 24 h
The values in parentheses are yields of the product using phenyl
isothiocyanate (1.0 mmol) at 60 °C for 24 h
a
The yield of the benzylic-attacked product
performed with a Heraeus CHN-O-Rapid analyzer. The
results agreed favorably with the calculated values.
2-(5-Methyl-5-propyl-1,3-oxathiolan-2-ylidene)-
malononitrile (5k, C10H12N2OS)
The crude product was purified by column chromatography
(SiO2; hexane/EtOAc 4/1, Rf = 0.47) affording 0.20 g
(95 %) 5j. Yellow oil; IR (KBr): v = 2967, 2248, 2235,
General procedure for the preparation
of compounds 5
1563, 1315, 1124 cm-1 1H NMR (500 MHz, CDCl3):
;
To a stirred solution of 0.061 g malononitrile (1 mmol),
heterocumulene (1 mmol), and strained heterocycles
(1.5 mmol) in 3 cm3 DMF was added 0.07 g Li2CO3
(1 mmol, 0.07 g) in one portion. The mixture was stirred
for 18–24 h at 25–60 °C. After completion of the reaction
(monitored by TLC), 5 cm3 EtOAc and 3 cm3 H2O were
added to the reaction mixture. Two layers were seperated
and aqueous layer was extracted with EtOAc (3 9 5 cm3).
The combined organic layers were dried over magnesium
sulfate, filtered, and concentrated in vacuo. The residue
was purified by column chromatography on silica gel
(hexane/ethyl acetate 4:1). All the known compounds (5a–
d = 0.90 (t, 3J = 6.4 Hz, Me), 1.23 (s, Me), 1.32–1.37 (m,
2 CH2), 3.25–3.36 (m, CH2) ppm; 13C NMR (125.7 MHz,
CDCl3): d = 12.5 (CH2), 14.7 (Me), 23.1 (Me), 30.4
(CH2), 37.6 (CH2), 87.1 (C), 88.4 (C), 111.2 (CN), 113.7
(CN), 189.2 (C) ppm; EI-MS (70 eV): m/z (%) = 208.0
(M?, 5), 191 (47), 165 (62), 139 (32), 116 (84), 108 (52),
78 (73).
2-((4R,5S and 4S,5R)-4,5-Diphenyl-1,3-oxathiolan-2-yli-
dene)malononitrile (5l, C18H12N2OS)
The crude product was purified by column chromatography
(SiO2; hexane/EtOAc 4/1, Rf = 0.24) affording 0.27 g
Scheme 1
123

A. Samzadeh-Kermani
(89 %) 5l. Pale yellow crystals; m.p.: 121–123 °C; IR
(KBr): v = 3025, 2971, 2251, 2240, 1568, 1315,
m/z (%) = 381 (M?, 1), 348 (35), 304 (68), 226 (79),
194 (82), 103 (42), 77 (100).
1122 cm-1 1H NMR (500 MHz, CDCl3): d = 4.41 (s,
;
2-(4-Benzyl-3-tosylthiazolidin-2-ylidene)malononitrile
(8b, C20H17N3O2S2)
CH), 5.61 (s, CH), 7.11–7.28 (m, 10 CH) ppm; 13C NMR
(125.7 MHz, CDCl3): d = 56.4 (CH), 83.2 (CH), 89.5 (C),
113.2 (CN), 114.1 (CN), 126.3 (2 CH), 126.7 (CH), 128.5
(CH), 128.7 (2 CH), 129.4 (2 CH), 130.2 (2 CH), 141.3 (C),
142.5 (C), 189.7 (C) ppm; EI-MS (70 eV): m/z (%) = 304
(M?, 12), 197 (36), 181 (62), 93 (52), 77 (100), 54 (71).
The crude product was purified by column chromatography
(SiO2; hexane/EtOAc 4/1, Rf = 0.26) affording 0.33 g
(83 %) 8b. Pale yellow solid; m.p.: 147–149 °C; IR (KBr):
1
v = 3029, 2965, 1562, 1534, 1352, 1316, 1115 cm-1; H
NMR (500 MHz, CDCl3): d = 2.26 (s, Me), 2.64 (dd,
2J = 7.8 Hz, 3J = 6.3 Hz, CH), 2.78 (dd, 2J = 7.8 Hz,
2-((4R,5R and 4S,5S)-4,5-Diphenyl-1,3-oxathiolan-2-
ylidene)malononitrile (5m, C18H12N2OS)
2
3
3J = 10.5 Hz, CH), 3.21 (dd, J = 7.4 Hz, J = 6.5 Hz,
The crude product was purified by column chromatography
(SiO2; hexane/EtOAc 4/1, Rf = 0.29) affording 0.25 g
(82 %) 5m. Pale yellow crystals; m.p.: 169–171 °C; IR
(KBr): v = 3043, 2960, 2242, 2240, 1561, 1311,
CH), 3.39 (dd, 2J = 7.4 Hz, 3J = 10.5 Hz, CH), 4.90–4.95
3
(m, CH), 7.10–7.38 (m, 5 CH), 7.40 (d, J = 6.5 Hz, 2
CH), 7.79 (d, 3J = 6.3 Hz, 2 CH) ppm; 13C NMR
(125.7 MHz, CDCl3): d = 24.2 (Me), 35.7 (CH2), 40.2
(CH2), 63.7 (CH), 98.5 (C), 111.4 (CN), 113.5 (CN), 124.7
(CH), 126.2 (2 CH), 127.1 (2 CH), 129.8 (2 CH), 131.0 (2
CH), 136.2 (C), 141.2 (C), 144.3 (C), 192.5 (C) ppm; EI-
MS (70 eV): m/z (%) = 394 (M?, 6), 362 (35), 337 (18),
246 (46), 117 (75), 91 (100), 77 (43).
1128 cm-1 1H NMR (500 MHz, CDCl3): d = 4.09 (s,
;
CH), 5.72 (s, CH), 7.08–7.25 (m, 10 CH) ppm; 13C NMR
(125.7 MHz, CDCl3): d = 54.2 (CH), 85.9 (CH), 90.2 (C),
114.1 (CN), 114.4 (CN), 125.1 (2 CH), 126.2 (CH), 127.2
(2 CH), 127.9 (CH), 128.1 (2 CH), 130.4 (2 CH), 142.6 (C),
142.9 (C), 190.2 (C) ppm; EI-MS (70 eV): m/z (%) = 304
(M?, 12), 197 (48), 181 (72), 93 (31), 77 (100), 54 (62).
2-(4-Methyl-4-propyl-3-tosylthiazolidin-2-ylidene)-
malononitrile (8c, C17H19N3O2S2)
2-(5-Benzyl-1,3-oxathiolan-2-ylidene)malononitrile
(5n, C13H10N2OS)
The crude product was purified by column chromatography
(SiO2; hexane/EtOAc 3/1, Rf = 0.21) affording 0.31 g
(86 %) 8c. Pale yellow solid; m.p.: 146–147.5 °C; IR
(KBr): v = 3029, 2965, 1562, 1534, 1352, 1316,
The crude product was purified by column chromatography
(SiO2; hexane/EtOAc 4/1, Rf = 0.53) affording 0.21 g
(86 %) 5n. Pale yellow crystals; m.p.: 87–89 °C; IR (KBr):
1115 cm-1 1H NMR (500 MHz, CDCl3): d = 0.90 (t,
;
v = 3025, 2981, 2260, 2243, 1554, 1310, 1107 cm-1; H
3J = 6.4 Hz, Me), 1.23 (s, Me), 1.32–1.37 (m, 2 CH2),
1
3
2.32 (s, Me), 3.25–3.36 (m, CH2), 7.41 (d, J = 6.6 Hz, 2
NMR (500 MHz, CDCl3): d = 2.86–3.34 (m, 2 CH2),
4.83–4.93 (m, CH), 7.08 (t, J = 6.7 Hz, CH), 7.14 (d,
3
H), 7.83 (d, 3J = 6.2 Hz, H) ppm; 13C NMR
2
3J = 6.4 Hz, 2 CH), 7.22 (t, 3J = 6.8 Hz, 2 CH) ppm; 13
C
(125.7 MHz, CDCl3): d = 12.5 (CH2), 14.7 (Me), 22.8
(Me), 24.2 (Me), 30.4 (CH2), 37.6 (CH2), 63.7 (CH), 98.5
(C), 111.4 (CN), 113.5 (CN), 127.1 (2 CH), 129.8 (2 CH),
136.2 (C), 141.2 (C), 192.5 (C) ppm; EI-MS (70 eV):
m/z (%) = 361 (M?, 2), 287 (24), 212 (24), 206 (36), 155
(100).
NMR (125.7 MHz, CDCl3): d = 38.7 (CH2), 47.2 (CH2),
87.2 (CH), 88.7 (C), 113.5 (CN), 114.2 (CN), 125.2 (CH),
127.2 (2 CH), 130.8 (2 CH), 139.5 (C), 191.0 (C) ppm; EI-
MS (70 eV): m/z (%) = 242 (M?, 7), 151 (43), 134 (64),
119 (37), 91 (100), 77 (56).
2-(4-Phenyl-3-tosylthiazolidin-2-ylidene)malononitrile
(8a, C19H15N3O2S2)
2-(Hexahydro-3-tosylbenzo[d]thiazol-2(3H)-ylidene)-
malononitrile (8d, C17H17N3O2S2)
The crude product was purified by column chromatogra-
phy (SiO2; hexane/EtOAc 2/1, Rf = 0.46) affording
0.34 g (89 %) 8a. Pale yellow solid; m.p.: 144–146 °C;
IR (KBr): v = 3024, 2961, 1555, 1521, 1335, 1322,
The crude product was purified by column chromatography
(SiO2; hexane/EtOAc 2/1, Rf = 0.37) affording 0.32 g
(89 %) 8d. Pale yellow solid; m.p.: 213 °C; IR (KBr):
1
v = 3049, 2980, 1563, 1527, 1347, 1308, 1126 cm-1; H
1108 cm-1
;
1H NMR (500 MHz, CDCl3): d = 2.24 (s,
NMR (500 MHz, CDCl3): d = 1.42–1.85 (m, 3 CH2),
2.11–2.20 (m, CH2), 2.34 (s, Me), 3.12–3.20 (m, CH),
2
3
Me), 3.25 (dd, J = 7.6 Hz, J = 6.8 Hz, CH), 3.37 (dd,
2J = 7.6 Hz, 3J = 11.4 Hz, CH), 4.98–5.04 (m, CH),
3
4.68–4.72 (m, CH), 7.34 (d, J = 6.7 Hz, 2 H), 7.80 (d,
3
7.12–7.35 (m, 5 CH), 7.38 (d, J = 6.8 Hz, 2 CH), 7.79
3J = 6.9 Hz, 2 H) ppm; 13C NMR (125.7 MHz, CDCl3):
d = 23.8 (Me), 25.7 (CH2), 28.2 (CH2), 30.3 (CH2), 32.7
(CH2), 41.7 (CH2), 68.9 (CH), 100.2 (C), 114.1 (CN),
115.2 (CN), 126.5 (2 CH), 130.3 (2 CH), 137.9 (C), 142.3
(C), 194.1 (C) ppm; EI-MS (70 eV): m/z (%) = 359 (M?,
2), 251 (36), 170 (82), 155 (100), 109 (13), 82 (46).
(d, 3J = 6.7 Hz, 2 CH) ppm; 13C NMR (125.7 MHz,
CDCl3): d = 23.5 (Me), 36.1 (CH2), 64.1 (CH), 99.1 (C),
110.6 (CN), 113.2 (CN), 125.3 (CH), 126.5 (2 CH), 127.5
(2 CH), 129.3 (2 CH), 130.5 (2 CH), 135.5 (C), 140.5
(C), 145.1 (C), 193.7 (C) ppm; EI-MS (70 eV):
123

One-pot synthesis of heterocyclic compounds containing highly polarized double bond
2-(Octahydro-3-tosylcyclohepta[d]thiazol-2-ylidene)-
malononitrile (8e, C18H19N3O2S2)
v = 3460, 3067, 2962, 1621, 1549, 1521, 1338, 1317,
1115 cm-1 1H NMR (500 MHz, CDCl3): d = 1.38 (d,
;
The crude product was purified by column chromatography
(SiO2; hexane/EtOAc 3/1, Rf = 0.39) affording 0.19 g
(52 %) 8e. Pale yellow solid; m.p.: 129–132 °C; IR (KBr):
3J = 6.7 Hz, Me), 3.09 (dd, 2J = 7.1 Hz, 3J = 6.4 Hz,
CH), 3.22 (dd, 2J = 7.2 Hz, 3J = 12.3 Hz, CH), 4.21–4.24
(m, CH), 5.13 (s, CH), 6.42 (br s, OH), 7.07 (d,
3J = 6.7 Hz, 2 H), 7.11 (t, 3J = 6.4 Hz, H), 7.27 (t,
3J = 6.5 Hz, 2 H) ppm; 13C NMR (125.7 MHz, CDCl3):
d = 21.7 (Me), 31.7 (CH), 36.8 (CH2), 67.3 (CH), 114.1
(CN), 114.4 (CN), 122.5 (2 CH), 125.7 (CH), 131.3 (2 CH),
148.1 (C), 164.6 (C) ppm; EI-MS (70 eV): m/z (%) = 259
(M?, 6), 241 (29), 194 (31), 167 (42), 92 (63), 77 (100).
v = 3062, 2971, 1551, 1539, 1347, 1310, 1131 cm-1; H
1
NMR (500 MHz, CDCl3): d = 1.31–1.89 (m, 4 CH2),
2.23–2.28 (m, CH2), 2.33 (s, Me), 3.04–3.21 (m, CH),
3
4.47–4.56 (m, CH), 7.32 (d, J = 6.9 Hz, 2 H), 7.81 (d,
3J = 6.8 Hz, 2 H) ppm; 13C NMR (125.7 MHz, CDCl3):
d = 25.1 (Me), 29.2 (CH2), 30.5 (CH2), 31.3 (CH2), 34.2
(CH2), 43.0 (CH2), 47.2 (CH), 69.1 (CH), 101.7 (C), 113.5
(CN), 113.8 (CN), 127.1 (2 CH), 131.0 (2 CH), 135.2 (C),
143.1 (C), 192.8 (C) ppm; EI-MS (70 eV): m/z (%) = 373
(M?, 2), 278 (11), 170 (71), 170 (43), 155 (100), 112 (47),
97 (62).
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2-[5-(4-Methoxyphenyl)-3-tosylthiazolidin-2-ylidene]-
malononitrile (8f, C20H17N3O3S2)
The crude product was purified by column chromatography
(SiO2; hexane/EtOAc 5/1, Rf = 0.40) affording 0.37 g
(91 %) 8f. Pale yellow solid; m.p.: 128–130 °C; IR (KBr):
v = 3034, 2972, 1545, 1530, 1341, 1310, 1123 cm-1; H
1
NMR (500 MHz, CDCl3): d = 2.28 (s, Me), 3.56 (s, OMe),
4.23 (dd, 2J = 8.4 Hz, 3J = 6.6 Hz, CH), 4.23 (dd,
2J = 8.4 Hz, 3J = 12.1 Hz, CH), 4.37–4.42 (m, CH),
3
3
6.89 (d, J = 6.7 Hz, 2 H), 7.01 (d, J = 6.5 Hz, 2 H),
3
3
7.32 (d, J = 7.0 Hz, 2 H), 7.79 (d, J = 6.7 Hz, 2 H)
ppm; 13C NMR (125.7 MHz, CDCl3): d = 24.3 (Me), 47.8
(CH), 56.5 (OMe), 64.2 (CH2), 98.9 (C), 113.7 (CN), 113.9
(CN), 114.2 (2 CH), 126.2 (2 CH), 130.1 (2 CH), 131.4 (2
CH), 135.0 (C), 137.3 (C), 143.2 (C), 160.5 (C), 185.8
(C) ppm; EI-MS (70 eV): m/z (%) = 411 (M?, 2), 256
(21), 169 (61), 134 (73), 155 (51), 107 (100).
2-[(2-Hydroxypropylthio)(phenylimino)methyl]-
malononitrile (4, C13H13N3OS)
The crude product was purified by column chromatography
(SiO2; hexane/EtOAc 3/1, Rf = 0.27) affording 0.23 g
(87 %) 4. Pale yellow solid; m.p.: 78–81 °C; IR (KBr):
123