D
N. Aoyagi, T. Endo
Letter
Synlett
References and Notes
dropwise to the mixture. The resulting mixture was stirred at
25 °C for 24 h then diluted with CHCl3 (2 mL) and washed with
H2O (3 × 2 mL). The aqueous phase was extracted with CHCl3 (2
mL), and the combined organic layers were dried (Na2SO4) and
concentrated in vacuo. The residue was purified by column
chromatography [silica gel, hexane–acetone (8:1 or 5:1)]. The
first (minor) fraction was the cyclic trithiocarbonate (yellow oil
or solid) byproduct 4a–d and the second (major) fraction was
the cyclic dithiocarbonate major product 3a–d (pale-yellow oil).
5-(Phenoxymethyl)-1,3-oxathiolane-2-thione (3a)
(1) New address: Molecular Engineering Institute, Kyushu Institute
of Technology, 1-1 Sensui-cho, Tobata, Kitakyushu, Fukuoka
804-8550, Japan.
(2) Robbe, Y.; Fernandez, J.-P.; Dubief, R.; Chapat, J.-P.; Sentenac-
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1986, 27, 1109. (b) Uenishi, J.; Kunugi, T.; Kudo, Y. Heteroat.
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Pale-yellow oil; yield: 221 mg (98%). 1H NMR (400 MHz, CDCl3,
25 °C): = 3.75 (dd, J = 11.4, 7.4 Hz, 1 H, OCHCHHS), 3.81 (dd,
J = 11.0, 7.8 Hz, 1 H, OCHCHHS), 4.29 (dd, J = 10.0, 4.8 Hz, 1 H,
PhOCHH), 4.33 (dd, J = 10.0, 5.6 Hz, 1 H, PhOCHH), 5.41–5.48
(m, 1 H, OCHCH2S), 6.90–6.95 (m, 2 H, 2-Ph-H, 6-Ph-H), 6.99–
7.04 (m, 1 H, 4-Ph-H), 7.29–7.34 (m, 1 H, 3-Ph-H, 5-Ph-H). 13C
NMR (100 MHz, CDCl3, 25 °C): = 36.3 (OCHCH2S), 66.2
(PhOCH2), 87.7 (OCHCH2S), 114.5 (2-Ph, 6-Ph), 121.9 (4-Ph),
129.7 (3-Ph, 5-Ph), 157.7 (1-Ph), 211.2 (C=S). EI-HRMS: m/z [M+]
calcd for C10H10O2S2: 226.0122; found: 226.0123.
(8) Ochiai, B.; Ogihara, T.; Mashiko, M.; Endo, T. J. Am. Chem. Soc.
2009, 131, 1636.
(9) Ochiai, B.; Konta, H. Molecules 2015, 20, 15049.
(10) Kihara, N.; Nakawaki, Y.; Endo, T. J. Org. Chem. 1995, 60, 473.
(11) Diebler, J.; Spannenberg, A.; Werner, T. Org. Biomol. Chem. 2016,
14, 7480.
(12) Maggi, R.; Malmassari, C.; Oro, C.; Pela, R.; Sartori, G.; Soldi, L.
Synthesis 2008, 53.
(13) Wu, J.-Y.; Luo, Z.-B.; Dai, L.-X.; Hou, X.-L. J. Org. Chem. 2008, 73,
9137.
(14) Clegg, W.; Harrington, R. W.; North, M.; Villuendas, P. J. Org.
Chem. 2010, 75, 6201.
(15) Taguchi, Y.; Yanagiya, K.; Shibuya, I.; Suhara, Y. Bull. Chem. Soc.
Jpn. 1988, 61, 921.
(16) Halimehjani, A. Z.; Ebrahimi, F.; Azizi, N.; Saidi, M. R. J. Hetero-
cycl. Chem. 2009, 46, 347.
(17) Shen, Y.-M.; Duan, W.-L.; Shi, M. Eur. J. Org. Chem. 2004, 3080.
(18) Cao, J.; Yu, M.; Li, H.; Wang, L.; Zhu, X.; Wang, G.; Shi, Y.; Cao, C.
Res. Chem. Intermed. 2015, 41, 5323.
(19) Ghazanfarpour-Darjani, M.; Khodakarami, A. Monatsh. Chem.
2016, 147, 829.
(20) Aoyagi, N.; Endo, T. Tetrahedron Lett. 2018, 59, 1702.
(21) 1-Ethyl-2-methyl-4,5-dihydro-1H-imidazole (1c)
N,N-Dimethylacetamide dimethyl acetal (90% purity; 8.14 g, 55
mmol) was added to a mixture of N-ethylethane-1,2-diamine
(4.41 g, 50 mmol) in anhyd toluene (50 mL) at rt, and the
mixture was stirred at 80 °C for 24 h. The mixture was concen-
trated in vacuo, and the residue was distilled under reduced
pressure to give a colorless liquid; yield: 5.27 g (94%); bp 56–
58 °C at 1.0 kPa. 1H NMR (400 MHz, CDCl3, 25 °C): = 1.13 (t,
J = 7.2 Hz, 3 H, CH2CH3), 1.91 (s, 3 H, CH3), 3.14 (q, J = 7.2 Hz, 2 H,
CH2 CH3), 3.27 (t, J = 9.6 Hz, 2 H, CH2CH2), 3.63 (t, J = 9.4 Hz, 2 H,
CH2CH2). 13C NMR (100 MHz, CDCl3, 25 °C): = 13.4 (CH2CH3),
14.0 (CH3), 41.1 (CH2CH3), 49.0 (CH2CH2), 51.6 (CH2CH2), 164.3
(N=C–N). EI-MS: m/z = 112 [M+].
4-(Phenoxymethyl)-1,3-dithiolane-2-thione (4a)
Yellow solid; mp (4.9 mg, 2%); mp 68–70 °C. 1H NMR (400 MHz,
CDCl3, 25 °C): = 4.07 (dd, J = 12.2, 3.8 Hz, 1 H, SCHCHHS), 4.20
(dd, J = 10.2, 5.4 Hz, 1 H, SCHCHHS), 4.22 (dd, J = 12.2, 5.4 Hz, 1
H, PhOCHH), 4.37 (dd, J = 9.6, 9.6 Hz, 1 H, PhOCHH), 4.60–4.67
(m, 1 H, SCHCH2S), 6.90–6.94 (m, 2 H, 2-Ph-H, 6-Ph-H), 6.99–
7.04 (m, 1 H, 4-Ph-H), 7.29–7.34 (m, 2 H, 3-Ph-H, 5-Ph-H). 13C
NMR (100 MHz, CDCl3, 25 °C): = 44.9 (SCHCH2S), 57.2
(SCHCH2S), 66.5 (PhOCH2), 114.6 (2-Ph, 6-Ph), 121.9 (4-Ph),
129.7 (3-Ph, 5-Ph), 157.7 (1-Ph), 226.4 (C=S). EI-HRMS: m/z [M+]
calcd for C10H10OS3: 241.9894; found: 241.9891.
(2-Thioxo-1,3-oxathiolan-5-yl)methyl Methacrylate (3b)
Pale-yellow oil; yield: 202 mg (93%). 1H NMR (400 MHz, CDCl3,
25 °C): = 1.97 (br s, 3 H, CH3), 3.59 (dd, J = 11.2, 8.0 Hz, 1 H,
OCHCHHS), 3.72 (dd, J = 11.4, 7.5 Hz, 1 H, OCHCHHS), 4.48 (dd,
J = 12.4, 5.2 Hz, 1 H, CO2CHH), 4.54 (dd, J = 12.4, 4.0 Hz, 1 H,
CO2CHH), 5.36–5.42 (m, 1 H, OCHCH2S), 5.67 (quin, J = 1.4 Hz, 1
H, C = CHH), 6.18–6.20 (m, 1 H, C=CHH). 13C NMR (100 MHz,
CDCl3, 25 °C): = 18.2 (CH3), 36.0 (OCHCH2S), 63.3 (CO2CH2),
87.4 (OCHCH2S), 127.2 (C=CH2), 135.2 (C=CH2), 166.6 (C=O),
210.9 (C=S). EI-HRMS: m/z [M+] calcd for C8H10O3S2: 218.0071;
found: 218.0066.
(2-Thioxo-1,3-dithiolan-4-yl)methyl Methacrylate (4b)
Yellow oil; yield: 12 mg (5%). 1H NMR (400 MHz, CDCl3, 25 °C):
= 1.97 (t, J = 1.2 Hz, 3 H, CH3), 3.86 (dd, J = 12.4, 4.0 Hz, 1 H,
SCHCHHS), 4.16 (dd, J = 12.2, 5.8 Hz, 1 H, SCHCHHS), 4.47 (dd,
J = 11.2, 6.4 Hz, 1 H, CO2CHH), 4.51 (dd, J = 11.4, 7.4 Hz, 1 H,
CO2CHH), 4.55–4.62 (m, 1 H, SCHCH2S), 5.65–5.67 (m, 1 H,
C=CHH), 6.15–6.18 (m, 1 H, C=CHH). 13C NMR (100 MHz, CDCl3,
25 °C): = 18.2 (CH3), 44.9 (SCHCH2S), 56.9 (SCHCH2S), 63.1
(CO2CH2), 126.9 (C=CH2), 135.4 (C=CH2), 166.6 (C=O), 225.8
(C=S). EI-HRMS: m/z [M+] calcd for C8H10O2S3: 233.9843; found:
233.9843.
(22) Aoyagi, N.; Furusho, Y.; Sei, Y.; Endo, T. Tetrahedron 2013, 69,
5476.
(23) The pKa values were calculated by using: ACD/Labs Software,
Version 11.02; Advanced Chemistry Development, Inc: Toronto,
2019.
(24) Cyclic Dithiocarbonates (3a–d); General Procedure
A mixture of CS2 (2 mmol) and 1a (0.01–0.03 mmol) was stirred
at 25 °C for 10 min, and then a dilute solution of the appropriate
epoxide 2a–d (1 mmol) in toluene or p-xylene (1 mL) was added
5-(Butoxymethyl)-1,3-oxathiolane-2-thione (3c)
Pale-yellow oil (195 mg, 95%). 1H NMR (400 MHz, CDCl3, 25 °C):
= 0.93 (t, J = 7.4 Hz, 3 H, CH3), 1.38 (sext, J = 7.2 Hz, 2 H,
CH3CH2), 1.53–1.61 (m, 2 H, CH3CH2CH2), 3.53 (t, J = 6.4 Hz, 2 H,
CH2CH2O), 3.61 (dd, J = 11.2, 7.2 Hz, 1 H, OCHCHHS), 3.69 (dd,
J = 10.8, 8.4 Hz, 1 H, OCHCHHS), 3.74 (dd, J = 11.0, 4.6 Hz, 1 H,
CH2CH2OCHH), 3.80 (dd, J = 10.8, 5.2 Hz, 1 H, CH2CH2OCHH),
5.20–5.26 (m, 1 H, OCHCH2S). 13C NMR (100 MHz, CDCl3, 25 °C):
= 13.8 (CH3), 19.2 (CH3CH2), 31.5 (CH3CH2CH2), 36.2
© 2019. Thieme. All rights reserved. Synlett 2019, 30, A–E