TOROSYAN et al.
914
6 mg of Bu4NI as phase-transfer catalyst. After ap-
propriate treatment and chromatographic purification
(SiO2, petroleum ether–ethyl acetate, 5:1), we isolated
0.7 g (95%) of 2b as oily material. IR spectrum, ν,
cm–1: 2948, 1703, 1699, 1532, 1464, 1441, 1395, 1303,
4-Methyl-4H-thieno[3,2-b]pyrrole-5-carboxylic
acid (3a). mp 172–174°C; published data [16]:
mp 154°C. IR spectrum, ν, cm–1: 3445, 3094, 3080,
272, 2655, 2593, 1657, 1545, 1493, 1417, 1366, 1249,
1
1176, 1080, 908, 717. H NMR spectrum (CDCl3,
1
300 MHz), δ, ppm: 4.04 s (3H, NCH3), 7.05 d (1H,
3-H, J = 5.1 Hz), 7.16 s (1H, 6-H), 7.42 d (1H, 2-H,
J = 5.3 Hz). 13C NMR spectrum (CDCl3, 125 MHz),
δC, ppm: 33.37 (NCH3), 108.73 (C6), 109.81 (C3),
121.47 (C6a), 126.75 (C5), 128.66 (C2), 134.80
(C3a), 163.31 (C=O). Mass spectrum, m/z (Irel, %): 180
[M – H]+ (100), 221 [M – H + MeCN]+ (26).
C8H7NO2S. Calculated: M 181.0197.
1256, 1216, 1175, 1103, 759, 719. H NMR spectrum
(CDCl3, 500 MHz), δ, ppm: 3.86 s (3H, OMe),
4.98 d.d (1H, =CH2, J = 17.1, 1.1 Hz), 5.13 d.d (1H,
=CH2, J = 16.6, 1.2 Hz), 5.14–5.16 m (2H, NCH2),
6.01 q.d.q (1H, =CH, J = 5.3, 5.1, 17.0 Hz), 6.92 d
(1H, 3-H, J = 5.5 Hz), 7.21 s (1H, 6-H), 7.33 d (1H,
2-H, J = 5.3 Hz). 13C NMR spectrum (CDCl3,
125 MHz), δC, ppm: 49.38 (NCH2), 51.31 (OMe),
109.51 (C6), 110.44 (=CH2), 116.34 (C3), 122.24 (C6a),
125.86 (C5), 129.32 (C2), 133.95 (=CH), 145.14
(C3a), 161.92 (C=O). Found: m/z 221.0505 [M]+.
C11H11NO2S. Calculated: M 221.0510.
4-(Prop-2-en-1-yl)-4H-thieno[3,2-b]pyrrol-5-yl-
methanol (5b). A solution of 60 mg (0.27 mmol) of
compound 2b in 5 mL of anhydrous THF was added
dropwise with stirring under argon to a suspension of
12 mg (0.32 mmol) of LiAlH4 in 10 mL of anhydrous
THF. The mixture was stirred until the initial com-
pound disappeared (TLC) and treated with a solution
of ammonium chloride. Tetrahydrofuran was distilled
off, and the residue was extracted with methylene
chloride (3×10 mL). The combined extracts were
washed with brine, dried over MgSO4, and evaporated,
and the residue was purified by column chromatog-
raphy on silica gel using petroleum ether–ethyl acetate
(5:1) as eluent. Yield 38 mg (72%), oily material. IR
spectrum, ν, cm–1: 2948, 1703, 1699, 1532, 1464,
1441, 1395, 1303, 1256, 1216, 1175, 1103, 759, 719.
1H NMR spectrum (CDCl3, 500 MHz), δ, ppm:
1.82 br.s (1H, OH), 4.65 s (2H, OCH2), 4.75 d (2H,
NCH2, J = 4.8 Hz), 4.99 d (1H, =CH2, J = 17.1 Hz),
5.16 d (1H, =CH2, J = 10.1 Hz), 5.99 d.d.d (1H, =CH,
J = 5.1, 10.2, 5.3 Hz), 6.38 s (1H, 6-H), 6.89 d (1H,
3-H, J = 5.1 Hz), 7.09 d (1H, 2-H, J = 5.3 Hz).
13C NMR spectrum (CDCl3, 75 MHz), δC, ppm: 48.04
(NCH2), 57.51 (OCH2), 101.17 (C6), 110.46 (=CH2),
116.57 (C3), 121.94 (C6a), 122.01 (C5), 123.78 (C2),
134.06 (=CH), 141.47 (C3a). Found, %: C 62.48;
H 5.49; N 7.46; S 16.98. C10H11NOS. Calculated, %:
C 62.15; H 5.74; N 7.25; S 16.59.
Methyl 4-(prop-2-yn-1-yl)-4H-thieno[3,2-b]pyr-
role-5-carboxylate (2c) was synthesized from 0.37 g
(2.04 mmol) of compound 1 and 0.45 mL (4.10 mmol)
of a 80% solution of propargyl bromide in toluene.
Yield 0.42 g (94%), bright yellow crystals, mp 83–
86°C. IR spectrum, ν, cm–1: 3106, 3265, 2953, 1692,
1534, 1492, 1464, 1438, 1394, 1377, 1306, 1261,
1220, 1181, 1171, 1111, 776, 732, 659. 1H NMR spec-
trum (CDCl3, 500 MHz), δ, ppm: 2.32 t (1H, ≡CH, J =
2.3 Hz), 3.88 s (3H, OMe), 5.38 d (2H, CH2, J =
2.4 Hz), 7.09 d (1H, 3-H, J = 5.2 Hz), 7.22 s (1H,
6-H), 7.38 d (1H, 2-H, J = 5.2 Hz). 13C NMR spectrum
(CDCl3, 125 MHz), δC, ppm: 36.13 (NCH2), 51.46
(OMe), 72.52 (≡CH), 78.41 (≡C), 110.10 (C6), 110.54
(C3), 122.60 (C6a), 125.47 (C5), 129.73 (C2), 144.60
(C3a), 163.0 (C=O). Found: m/z 219.0349 [M]+.
C11H9NO2S. Calculated: M 219.0354.
Methyl 4-benzyl-4H-thieno[3,2-b]pyrrole-5-car-
boxylate (2d) was synthesized from 0.06 g
(0.33 mmol) of compound 1 and 0.084 g (0.66 mmol)
of benzyl bromide. Yield 82 mg (92%), yellowish crys-
tals, mp 81–83°C. IR spectrum, ν, cm–1: 2950, 1703,
1532, 1490, 1464, 1441, 1395, 1303, 1257, 1216,
1175, 1103, 1085, 991, 918, 781, 759, 719, 666.
1H NMR spectrum (CDCl3, 500 MHz), δ, ppm: 3.83 s
(3H, OMe), 5.76 s (1H, NCH2), 6.86 d (1H, 3-H, J =
5.4 Hz), 7.13 d (2H, Ph, J = 7.4 Hz), 7.25 s (1H, 6-H),
7.23–7.28 m (3H, Ph), 7.32 d (1H, 2-H, J = 5.7 Hz).
13C NMR spectrum (CDCl3, 125 MHz), δC, ppm: 50.39
(NCH2), 51.28 (OMe), 109.78 (C6), 110.58 (C3),
122.39 (C6a), 126.09 (C5), 126.65 (Carom), 127.34
(Carom), 128.56 (Carom), 129.44 (C2), 137.94 (Carom),
145.43 (C3a), 161.90 (C=O). Found: m/z 271.0662
[M]+. C15H13NO2S. Calculated: M 271.0667.
Compounds 5a, 5c, and 5d were synthesized in
a similar way.
4-Methyl-4H-thieno[3,2-b]pyrrol-5-ylmethanol
(5a) was synthesized from 70 mg (0.36 mmol) of
compound 2a using 40.0 mg (1.05 mmol) of LiAlH4.
Yield 38 mg (63%), mp 71–73°C. IR spectrum, ν,
cm–1: 3527, 3230, 2727, 1530, 1377, 1366, 1337, 1295,
1241, 1135, 1078, 987, 975, 823, 763, 713, 654.
1H NMR spectrum (acetone-d6, 300 MHz), δ, ppm:
2.86 s (1H, OH), 3.79 s (3H, NCH3), 4.64 d (2H,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 54 No. 6 2018