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T. Mizuno et al. / Tetrahedron 61 (2005) 9157–9163
10 mmol) was vigorously stirred under carbon monoxide
(1 atm) at 20 8C for 5 h. Into the DMSO solution of
thiocarbamate salt (3a), methyl iodide (0.75 mL, 12 mmol)
was added slowly at 0 8C under argon atmosphere. The
reaction mixture was stirred for additional 1 h at 20 8C. The
resulting mixture was then poured into 1 N HCl (100 mL)
and extracted with t-butyl methyl ether (100 mL, 50 mL!
2). After evaporation of solvents and purification by short-
column chromatography (silica gel, toluene/AcOEtZ1:1),
S-methyl N,N-dipropylthiocarbamate (1a) was afforded in
88% yield (1.54 g).
d 13.4, 35.2, 67.8, 126.7, 128.6, 128.9, 137.3, 171.6; MS
(m/z, %) 196 (MC, 0.2), 105 (100), 104 (100), 91 (99), 77
(68). Exact MS calcd for C10H12O2S: 196.0558. Found:
196.0547.
4.3.3. S-Ethyl O-decyl carbonothioate (4f). Oil; IR (neat)
2925, 2855, 1715, 1145 cmK1; 1H NMR (300 MHz, CDCl3)
d 0.88 (t, JZ7 Hz, 3H), 1.26–1.34 (m, 17H), 1.61–1.68 (m,
2H), 2.86 (q, JZ7 Hz, 2H), 4.20 (t, JZ7 Hz, 2H); 13C NMR
(75 MHz, CDCl3) d 14.1, 15.0, 22.7, 25.3, 25.8, 28.7, 29.2,
29.3, 29.5, 29.5, 31.9, 67.5, 171.2; MS (m/z, %) 246 (MC,
7), 185 (28), 85 (59), 71 (80), 57 (100). Exact MS calcd for
C13H26O2S: 246.1654. Found: 246.1637.
4.2.1. S-Methyl N,N-dipropylthiocarbamate (1a).4,12,13,17
Oil; IR (neat) 2965, 1655, 1405, 1225, 1125 cmK1; 1H NMR
(300 MHz, CDCl3) d 0.90 (t, JZ7 Hz, 6H), 1.60 (br s, 4H),
2.32 (s, 3H), 3.28 (br s, 4H); 13C NMR (75 MHz, CDCl3) d
11.2, 12.8, 21.4, 49.3, 168.2; MS (m/z, %) 175 (MC, 100),
128 (89), 86 (79), 75 (65). Exact MS calcd for C8H17NOS:
175.1031. Found: 175.1012.
4.3.4. S-Ethyl O-stearyl carbonothioate (4g). Oil; IR
1
(neat) 2925, 2850, 1715, 1145 cmK1; H NMR (300 MHz,
CDCl3) d 0.88 (t, JZ7 Hz, 3H), 1.26–1.34 (m, 33H), 1.63–
1.68 (m, 2H), 2.86 (q, JZ7 Hz, 2H), 4.20 (t, JZ7 Hz, 2H);
13C NMR (75 MHz, CDCl3) d 14.1, 15.0, 22.7, 25.3, 25.8,
28.7, 29.2, 29.4, 29.5, 29.5, 29.6, 29.7, 29.7, 31.9, 67.4,
171.1; MS (m/z, %) 358 (MC, 14), 297 (43), 85 (74), 71
(83), 57 (100). Exact MS calcd for C21H42O2S: 358.2906.
Found: 358.2909.
4.2.2. S-Methyl perhydroazepin-1-carbothioate (1l). Oil;
IR (neat) 2925, 1650, 1405, 1155 cmK1
;
1H NMR
(300 MHz, CDCl3) d 1.54–1.58 (m, 4H), 1.74 (br s, 4H),
2.33 (s, 3H), 3.45 (q, JZ6 Hz, 2H), 3.57 (t, JZ6 Hz, 2H);
13C NMR (75 MHz, CDCl3) d 12.9, 26.9, 27.2, 27.9, 28.4,
47.4, 47.6, 168.2; MS (m/z, %) 173 (MC, 41), 126 (100), 83
(18), 55 (48). Exact MS calcd for C8H15NOS: 173.0874.
Found: 173.0861.
4.3.5. S-Ethyl O-2-ethylhexyl carbonothioate (4h). Oil; IR
1
(neat) 2960, 2930, 1710, 1150 cmK1; H NMR (300 MHz,
CDCl3) d 0.89 (t, JZ7 Hz, 6H), 1.29–1.41 (m, 11H), 1.53–
1.62 (m, 1H), 2.86 (q, JZ7 Hz, 2H), 4.13 (d, JZ6 Hz, 1H),
4.14 (d, JZ6 Hz, 1H); 13C NMR (75 MHz, CDCl3) d 10.9,
14.0, 15.0, 22.9, 23.7, 25.3, 28.9, 30.2, 38.9, 69.7, 171.2;
MS (m/z, %) 218 (MC, 4), 157 (8), 112 (24), 71 (92), 57
(100). Exact MS calcd for C11H22O2S: 218.1341. Found:
218.1341.
Identification of the other S-alkyl thiocarbamates 1b–k,
1m–o was performed by comparison of the IR, NMR, MS
spectra, and mp of 1b–k, 1m–o with those of authentic
samples, which were prepared according to the literatures,
1b, 1g–k, 1n, 1o,17 1c, 1e, 1f, 1m,18 and 1d.13
Identification of the other S-methyl O-alkyl carbonothioates
4b–d and S-methyl O-phenyl carbonothioate (4i) was
performed by comparison of the IR, NMR, and MS spectra
of 4b–d and 4i with those of authentic samples, which were
prepared according to the literatures.20,21
4.3. General synthetic method of S-methyl O-benzyl
carbonothioate (4a) under mild conditions
Into DMSO (20 mL), benzyl alcohol (5a) (1.03 mL,
10 mmol), powdered sulfur (321 mg, 10 mmol) and DBU
(1.50 mL, 10 mmol) were added. The solution was very
vigorously stirred under carbon monoxide (1 atm) at 20 8C
for 5 h. Then, methyl iodide (0.75 mL, 12 mmol) was added
carefully at 0 8C under argon atmosphere in the DMSO
solution of carbonothioate salt (6a). The solution was stirred
for additional 1 h at 20 8C. The resulting mixture was then
poured slowly into 1 N HCl (100 mL), and extracted with
t-butyl methyl ether (100 mL, 50 mL!2). After evapor-
ation of solvents and purification by short-column
chromatography (silica gel, toluene), S-methyl O-benzyl-
carbonothioate (4a) was obtained in 67% yield (1.23 g).
References and notes
1. Sanders, H. J. Chem. Eng. News 1981, 59, 20–35.
2. Sugiyama, H. J. Synth. Org. Chem. Jpn. 1980, 38, 555–563.
3. Uesugi, Y.; Ueji, M.; Koshioka, M. Pesticide Data Book, 3rd
ed.; Soft Science: Tokyo, 1997.
4. Tilles, H. J. Am. Chem. Soc. 1959, 81, 714–727.
5. Chin-Hsien, W. Synthesis 1981, 622–623.
6. Recently S-alkyl thiocarbamates 1 were synthesized by the
reaction of trichloroacetyl chloride with amines 2 and thiols.7
7. Wynne, J. H.; Jensen, S. D.; Snow, A. W. J. Org. Chem. 2003,
68, 3733–3735.
4.3.1. S-Methyl O-benzyl carbonothioate (4a).20,21 Oil; IR
1
(neat) 1710, 1135 cmK1; H NMR (300 MHz, CDCl3) d
2.35 (s, 3H), 5.24 (s, 2H), 7.36 (s, 5H); 13C NMR (75 MHz,
CDCl3) d 13.4, 68.9, 128.4, 128.5, 135.5, 171.6; MS (m/z,
%) 182 (MC, 69), 92 (48), 91 (100), 77 (27), 65 (36). Exact
MS calcd for C9H10O2S: 182.0402. Found: 182.0368.
8. Franz, R. A.; Applegath, F. J. Org. Chem. 1961, 26,
3304–3305.
9. Franz, R. A.; Applegath, F.; Morriss, F. V.; Baiocchi, F.
J. Org. Chem. 1961, 26, 3306–3308.
4.3.2. S-Methyl O-2-phenylethyl carbonothioate (4e).
10. Franz, R. A.; Applegath, F.; Morriss, F. V.; Baiocchi, F.;
Bolze, C. J. Org. Chem. 1961, 26, 3309–3312.
11. Grisley, D. W., Jr.; Stephens, J. A. J. Org. Chem. 1961, 26,
3568.
Oil; IR (neat) 1710, 1145 cmK1 1H NMR (300 MHz,
;
CDCl3) d 2.33 (s, 3H), 2.98 (t, JZ7 Hz, 2H), 4.42 (t, JZ
7 Hz, 2H), 7.20–7.31 (m, 5H); 13C NMR (75 MHz, CDCl3)