1
892
TARASOVA et al.
temperature (170–180°C and above). Kaboudin and
Khodamorady [4] recently described N-formylation of
primary amines with triethyl orthoformate in boiling
water (1–2 days) or under microwave initiation (90°C,
column chromatography on neutral aluminum oxide
using first petroleum ether–diethyl ether and then pure
diethyl ether as eluents to isolate 2.55 g of unidentified
products and 0.45 g (5.2%) of a light brown powder
which was assigned the structure of formamide II on
the basis of the NMR data (a mixture of two isomers at
2
–3 h), which afforded the corresponding N-substitut-
ed formamides in good yield. However, there are no
published data on reactions of imidoformates with al-
cohols in the presence of bases, leading to NH-form-
amides. Moreover, we have found no publications on
the synthesis of any N-(buta-1,3-dienyl)formamides
which could be interesting as monomers, intermediate
products, and building blocks.
−1
a ratio of ~76:24). IR spectrum (KBr), ν, cm : 3212
and 3117 sh (N–H), 2980 w, 2934 w, 2888 w, 2831 w,
2731 w, 1825 w, 1681 s, 1662 s, 1618, 1580 w, 1517,
1434, 1398, 1327 w, 1263 s, 1233, 1103 w, 1047,
987 w, 975, 910, 836, 740 w, 669 w, 556 w, 527 w.
1
H NMR spectrum, δ, ppm: major cis-(E) isomer IIa:
2
.25 s (3H, SMe), 3.70 s (3H, OMe), 5.23 d.d (1H,
N-[(1Z)-2-Methoxy-1-methylsulfanylbuta-1,3-
dien-1-yl]formamide (II). A solution of 57.5 mmol of
butyllithium in a mixture of 23 ml of hexane and 90 ml
of tetrahydrofuran was cooled to –100°C, 5 g
3
2
CH =, J = 10.9, J = 1.5 Hz), 5.53 d.d (1H, CH =,
2
cis
2
3
2
3
Jtrans = 17.1, J = 1.5 Hz), 6.39 d.d (1H, CH=, J
=
trans
3
3
1
8
7.1, J = 10.9 Hz), 7.38 br.d (1H, NH, J = 10.8 Hz),
.11 d (1H, CH=O, J = 10.8 Hz); minor trans-(Z)
cis
3
(
71.4 mmol) of methoxyallene was added under vigor-
isomer IIb: 2.23 s (3H, SMe), 3.72 s (3H, OMe),
5
ous stirring in an argon atmosphere, the mixture was
stirred for 10 min at –55°C and cooled to –90°C, and
3
2
.21 d.d (1H, CH =, J = 10.9, J = 1.5 Hz), 5.50 d.d
2 cis
3
2
(
1H, CH =, J
= 17.1, J = 1.5 Hz), 6.28 d.d (1H,
trans
5
.15 g (50 mmol) of methoxymethyl isothiocyanate
2
3
3
CH=, J
= 17.1, J = 10.9 Hz), 6.81 br.s (1H,
was added. The mixture was stirred for 5 min at –55°C
and cooled to –70°C, 13.8 g (97.2 mmol) of methyl
iodide was added, and the cooling bath was removed.
When the mixture warmed up to 0°C, a sample was
withdrawn for NMR analysis. According to the NMR
data, the sample (before addition of KOH in MeOH)
trans
cis
1
3
NH), 8.30 s (1H, CH=O). C NMR spectrum, δ , ppm:
IIa: 14.59 (SMe), 59.44 (OMe), 116.58 (CH ), 120.99
C
2
(
(
(
(
S–C=), 126.08 (CH=), 152.37 (O–C=), 165.14
NC=O); IIb: 14.59 (SMe), 59.50 (OMe), 116.06
CH =), 122.65 (S–C=), 126.76 (CH=), 154.36
O–C=), 159.61 (NC=O). N NMR HMBC spectrum
), δ , ppm: –253.4 (IIa), –255.1 (IIb). Signals
2
1
5
1
contained 0.07 g of imidoformate I. H NMR spec-
trum, δ, ppm: 2.19 s (3H, SMe), 3.68 s and 3.83 s (3H
(CDCl
3
N
3
2
in the NMR spectra were assigned using two-dimen-
sional correlation techniques (NOESY, HSQC, HMBC).
Found, %: C 48.96; H 6.28; N 7.65; S 18.06.
each, OMe), 5.09 d.d (1H, CH =, J = 10.9, J =
2
cis
3
2
1
1
1
.8 Hz), 5.39 d.d (1H, CH =, J
= 17.4, J =
2
trans
3
3
.8 Hz), 6.74 d.d (1H, CH=, J
= 17.4, J
=
C
trans
cis
1
3
0.9 Hz), 7.97 s (1H, N=CH). C NMR spectrum, δ ,
C H11NO S. Calculated, %: C 48.53; N 6.40; N 8.09;
7 2
ppm: 15.33 (SMe), 53.82 (OMe), 59.45 (N=CHOCH3),
12.89 (CH =), 127.40 (CH=), 130.76 (S–C=), 149.61
S 18.51.
The IR spectrum was recorded on a Bruker Vertex
1
2
1
5
1
13
(
(
O–C=), 156.66 (N=CH). N NMR HMBC spectrum
CDCl ): δ –139.4 ppm. Signals in the NMR spectra
7
0 spectrometer. The H and C NMR spectra, as well
3
N
as two-dimensional spectra, were recorded on Bruker
1
were assigned using two-dimensional correlation tech-
niques (NOESY, HSQC, HMBC).
DPX-400 and AV-400 instruments at 400.13 ( H) and
1
3
1
00.62 MHz ( C) from solutions in CDCl ; the chem-
3
The mixture was then cooled again to –70°C, and
ical shifts were determined relative to hexamethyldi-
1
13
15
a solution of 29.5 g of KOH·0.5H O in 50 ml of meth-
siloxane ( H, C) or NH ( N). Tetrahydrofuran was
2
3
anol was added dropwise under stirring over a period
of ~5 min. The mixture was allowed to warm up to
room temperature, stirring was turned off, and the
mixture was left overnight (~14 h). The mixture was
treated with a dilute aqueous solution of ammonium
chloride and extracted with diethyl ether (4×40 ml),
the extracts were combined, washed with two portions
treated with dispersed potassium hydroxide (~50 g/l),
heated under reflux over metallic sodium, and then
distilled in the presence of benzophenone under argon.
Methoxyallene was prepared according to the proce-
dure described in [5]. Methoxymethyl isothiocyanate
was synthesized by heating chloro(methoxy)methane
with potassium thiocyanate in boiling pentane [6].
Butyllithium (a ~2.5 M solution in hexane) and other
reagents and solvents were commercial products.
Liquid nitrogen was used as cooling agent.
of water, and dried over MgSO , and the solvent was
4
removed under reduced pressure. The residue was
4
.46 g of a dark viscous liquid which was subjected to
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 12 2011
Tarasova
