Nakashima et al.
reduced pressure and the residue was purified by silica gel
-1.16 × 104), 228 ([θ] 4.70 × 104) nm. 1H, 13C NMR, MS, and
IR spectra were almost the same as those of the racemic
sample.
column chromatography (dichloromethane/ethyl acetate ) 4/1).
2-tert-Butyl-1,2-benzisoselenazol-3(2H)-one.8d Yield 93%;
mp 137-138 °C (pale orange needles from dichloromethane/
ethyl acetate); 1H NMR (500 MHz, CDCl3) δ 1.68 (9H, s), 7.40
(1H, dd, J ) 7.90, 6.40 Hz), 7.53-7.60 (2H, m), 7.96 (1H, d, J
) 7.96 Hz); 13C NMR (125 MHz, CDCl3) δ 28.9, 58.6, 123.2,
125.7, 128.1, 129.8, 131.3, 136.9, 166.8; 77Se NMR (95 MHz,
N,N′-Bis(1-adamantyl)-2,2′-dithiodibenzamide. To a
dichloromethane (20 mL) solution of 1-adamantanammonium
chloride (1.32 g, 7.00 mmol) and triethylamine (1.96 mL, 14.0
mmol) was slowly added a dichloromethane (50 mL) solution
of 2,2′-dithiodibenzoyl chloride15 (1.03 g, 3.00 mmol) over 15
min. After the mixture was stirred for 5.5 h, solvent was
evaporated and 1 M HCl (50 mL) was added to the residue,
then the mixture was stirred for 1 h. The product precipitated
was filtered, washed with water, and dried in vacuo (3.68 g).
Yield 98%; mp 162 °C (colorless needles from acetone/ethyl
CDCl3) δ 860; MS (EI, 70 eV) m/z 255 (M+, 80Se), 198 (M+
-
t
tBu, 80Se), 196 (M+ - Bu, 78Se); IR (KBr) 1589 (CdO), 1442,
1342 cm-1. Anal. Calcd for C11H13NOSe: N, 5.51; C, 51.98; H,
5.15. Found: N, 5.59; C, 51.84; H, 5.15.
General Procedure for Preparation of Seleninamides
1a and 1b. To a dichloromethane (3 mL) solution of selene-
namide (2 mmol) was added 30% hydrogen peroxide (2.4 mmol)
at 0 °C, and the mixture was stirred for an additional 2 h.
The precipitated product was filtered off and dried under
reduced pressure.
1
acetate; dec); H NMR (500 MHz, CDCl3) δ 1.72 (3H, d, J )
12.9 Hz), 1.74 (3H, d, J ) 12.9 Hz), 2.14 (9H, s), 5.76 (1H),
7.19 (1H, dd, J ) 7.95, 7.60 Hz), 7.31 (1H, dd, J ) 7.60, 7.65
Hz), 7.43 (1H, d, J ) 7.65 Hz), 7.73 (1H, d, J ) 7.95 Hz); 13C
NMR (125 MHz, CDCl3) δ 29.5, 36.3, 41.6, 52.9, 126.3, 127.3,
127.7, 130.7, 136.0, 136.3, 166.9; MS (EI, 30 eV) m/z 570 (M+
- 2), 285, 135; IR (KBr) 3314 (NH), 2904, 1627 (CdO), 1541,
2-tert-Butyl-1,2-benzisoselenazol-3(2H)-one 1-Oxide
(1a).8d Yield 70%; mp 114-115 °C (colorless needles from
1307, 741 cm-1
.
1
acetonitrile); H NMR (500 MHz, CDCl3) δ 1.76 (9H, s), 7.73
2-{1-Adamantyl}-1,2-benzisothiazol-3(2H)-one. To a
dichloromethane (20 mL) solution of N,N′-bis(1-adamantyl)-
2,2′-dithiodibenzamide (573 mg, 1.00 mmol) was slowly added
a dichloromethane (3 mL) solution of bromine (0.052 mL, 1.0
mmol) and the solution was stirred for an additional 15 h. To
the reaction mixture was added activated basic alumina (4 g)
followed by 3 h of stirring. The solvent was evaporated, and
the residue was purified by alumina column chromatography
(chloroform) (478 mg). Yield 84%; mp 174-175 °C (colorless
prisms from acetone); 1H NMR (500 MHz, CDCl3) δ 1.74 (3H,
d, J ) 11.8 Hz), 1.80 (3H, d, J ) 11.8 Hz), 2.21 (3H, s), 2.46
(6H, s), 7.35 (1H, dd, J ) 7.95, 7.00 Hz), 7.50 (1H, d, J ) 7.90
Hz), 7.56 (1H, dd, J ) 7.90, 7.00 Hz), 7.95 (1H, d, J ) 7.95
Hz); 13C NMR (125 MHz, CDCl3) δ 29.9, 36.1, 40.5, 59.7, 119.7,
124.9, 126.0, 127.1, 131.1, 139.8, 165.3; MS (EI, 30 eV) m/z
285 (M+), 151, 135; IR (KBr) 2908, 1647 (CdO), 1448, 1301,
748 cm-1. Anal. Calcd for C17H19NOS: N, 4.91; C, 71.54; H,
6.71. Found: N, 4.88; C, 71.11; H, 6.70.
(1H, dd, J ) 7.33, 7.00 Hz), 7.66 (1H, dd, J ) 7.33, 7.00 Hz),
7.81 (1H, d, J ) 7.00 Hz), 7.97 (1H, d, J ) 7.00 Hz); 13C NMR
(125 MHz, CDCl3) δ 29.9, 59.0, 126.4, 127.7, 132.2, 132.7,
133.6, 142.7, 168.0; 77Se NMR (95 MHz, CDCl3) δ 1081; MS
(EI, 30 eV) m/z 270 (M+ - 1, 80Se), 268 (M+ - 1, 78Se), 255
(M+ - O, 80Se), 253 (M+ - O, 78Se), 199; IR (KBr) 1625 (CdO),
1567, 1459, 1340, 1219, 827 (SedO), 744, 669 cm-1; UV
(hexane/2-propanol ) 3/1) λmax 274 (sh, ꢀ 2.64 × 103), 232 (sh,
ꢀ 1.11 × 104), 201 (ꢀ 3.32 × 104) nm.
General Procedure for Preparation of Seleninamides
1c and 1d. Ozone was bubbled into a dichloromethane (40
mL) solution of selenenamide (1 mmol) at -20 °C for 30 min,
and removal of the solvent under reduced pressure afforded
the product.
2-{2,4,6-Trimethylphenyl}-1,2-benzisoselenazol-3(2H)-
one 1-Oxide (1c). Yield 94%; mp 121 °C (colorless powder;
1
dec); H NMR (500 MHz, CDCl3) δ 2.14 (3H, s), 2.31 (3H, s),
2-{1-Adamantyl}-1,2-benzisothiazol-3(2H)-one 1-Oxide
(2a). Ozone was bubbled into a dichloromethane (30 mL)
solution of 2-{1-adamantyl}-1,2-benzisoselenazol-3(2H)-one
(114 mg, 0.40 mmol) at -20 °C for 8 min. Removal of the
solvent under reduced pressure afforded 2a (104 mg). Yield
86%; mp 172-173 °C (colorless prisms from dichloromethane/
2.32 (3H, s), 6.97 (1H, s), 7.01 (1H, s) ,7.82-7.88 (2H, m), 8.13-
8.16 (2H, m); 13C NMR (125 MHz, CDCl3) δ 18.5, 18.6, 21.0,
127.8, 128.6, 129.2, 129.5, 129.8, 129.9, 133.3, 134.5, 136.0,
139.0, 139.3, 144.4, 166.8; 77Se NMR (95 MHz, CDCl3) δ 1102;
MS (EI, 30 eV) m/z 333 (M+, 80Se), 317 (M+ - O, 80Se), 300,
298, 133; IR (KBr) 2908, 1686 (CdO), 1316, 1294, 853 (Sed
O), 745 cm-1; UV (hexane/2-propanol ) 3/1) λmax 270 (ꢀ 3.30 ×
103), 215 (ꢀ 2.43 × 104) nm; HRMS (30 eV) m/z 333.0279
(C16H15NO280Se requires 333.0268).
1
hexane); H NMR (500 MHz, CDCl3) δ 1.74 (3H, d, J ) 12.2
Hz), 1.81 (3H, d, J ) 12.2 Hz), 2.21 (3H, s), 2.46 (3H, d, J )
11.3 Hz), 2.51 (3H, d, J ) 11.3 Hz), 7.69 (1H, dd, J ) 7.30,
7.48 Hz), 7.74 (1H, dd, J ) 7.65, 7.48 Hz), 7.80 (1H, d, J )
7.65 Hz), 7.89 (1H, d, J ) 7.30 Hz); 13C NMR (125 MHz, CDCl3)
δ 29.8, 36.0, 41.1, 60.2, 124.2, 125.6, 129.7, 132.7, 133.6, 144.7,
165.9; MS (EI, 30 eV) m/z 301 (M+), 285 (M+ - O), 152, 135;
Optical Resolution of Seleninamide 1a-d. A racemic
sample of 1a-d (10-20 mg) in eluent (0.5 mL) was charged
to a chiral column packed with amylase carbamate derivative
silica gel (Daicel Chiralpak AS; 10 × 250 mm) and eluted with
hexane containing 25 (for 1a-c) and 2 (for 1d) vol % of
2-propanol at a flow rate of 1.5 mL min-1. The eluates
containing about 3-5 mg of optically active seleninamides
were collected from the first eluted portions and second
portions, respectively. In the case of 1d, the specific rotations
and the circular dichroism spectra were measured after
removal of the solvents under reduced pressure. In the case
of 1a-c the optical rotations and the circular dichroism spectra
were measured in the eluates because concentration of the
eluates caused racemization. The chemical structures of 1a-c
IR (KBr) 2894, 1693 (CdO), 1457, 1296, 1059 (SdO), 754 cm-1
;
UV (2-propanol) λmax 277 (ꢀ 2.97 × 103), 234 (sh, ꢀ 5.93 × 103),
200 (ꢀ 3.75 × 104) nm; Anal. Calcd for C17H19NO2S: N, 4.65;
C, 67.74; H, 6.35. Found: N, 4.61; C, 67.59; H, 6.35.
Optical Resolution of Sulfinamides 2a and 2b. A
racemic sample of 2a and 2b (10 mg) in eluent (0.5 mL) was
charged to a chiral column packed with cellulose carbamate
derivative silica gel (Daicel Chiralcel OD; 10 × 250 mm) and
a chiral column packed with amylase carbamate derivative
silica gel (Daicel Chiralpak AS; 10 × 250 mm), respectively,
and eluted with hexane containing 25 vol % of 2-propanol at
a flow rate of 1.5 mL min-1. In the case of 2a, about 5 mg of
optically active sulfinamides was collected from the first eluted
portion and the next portion, and optically pure (+)-2a was
obtained by repeated chromatography. In the case of 2b, 54%
ee of (+)-2b was obtained from the first half of the first peak.
Compound (R)-(+)-2a. 100% ee; mp 170 °C (colorless
prisms from acetone; dec); [R] 2D7 +72.8 (c 0.138, 2-propanol);
1
were confirmed by H NMR spectra after concentration.
Compound (R)-(-)-1d. 100% ee; mp 223 °C (colorless
powder; dec); [R] 2D9 -103 (c 0.091, dichloromethane); [R] 29
-202 (c 0.091, dichloromethane); CD (2-propanol) 273 ([θ] 1.44355
1
× 104), 230 ([θ] -6.06 × 104) nm. H, 13C NMR, MS, and IR
spectra were almost the same as those of the racemic sample.
Compound (S)-(+)-1d. 82% ee; mp 201 °C (colorless
powder; dec); [R] 2D9 +69.6 (c 0.116 dichloromethane); [R] 29
(15) Kamigata, N.; Hashimoto, S.; Kobayashi, M. Org. Prep. Proced.
Int. 1983, 15, 315.
435
+158 (c 0.116 dichloromethane); CD (2-propanol) 273 ([θ]
872 J. Org. Chem., Vol. 70, No. 3, 2005