Smallest Vicinal Tri- and Tetracarbonyl Compounds
a H2O bath at 70–80 °C for 8 h. The remaining yellow liquid was
dissolved in chloroform and filtered through a pad (3–4 cm) of Ce-
lite. The filtrate was concentrated to dryness with a rotary evapora-
tor and purified by thin layer chromatography using chloroform/
δ = 194.1, 43.8, 30.1, 26.2, 25.4 ppm. MS (FAB): m/z (%) = 266
(100) [M]+. C9H14OS4 (266.45): calcd. C 40.57, H 5.30; found C
40.52, H 5.39. Crystal data: Empirical formula C9H14OS4, formula
mass 266.48, crystal system orthorhombic, space group Pbcn (no.
petroleum ether (3:1) to afford white semisolid 6a (94 mg, 45%). 60), cell parameters: a = 6.8344(1), b = 18.0589(2), c = 9.4376(1) Å,
To a stirred solution of 1 (2 mL) in dioxane (4 mL), SeO2 (7.10 g,
0.06 mol) was added, and the mixture was heated at 100 °C for
16 h. The remaining yellow solution was dissolved in chloroform/
MeOH, filtered through a pad (3–4 cm) of Celite and washed well
with chloroform. The filtrate was concentrated to dryness with a
rotary evaporator and purified by thin layer chromatography using
silica gel (100–200 mesh) to afford 6a (1.50 g, 58%) in good yield.
Copper acetate (2 g, 0.01 mol) was dissolved in H2O (10 mL), and
5 (500 mg, 5.5 mmol) was added. The resulting mixture was heated
at reflux for 12 h, cooled to 25 °C and then extracted with chloro-
form. The organic layer was dried (anhydrous Na2SO4), and the
solvent was removed under reduced pressure. The crude product
was purified on silica gel by using chloroform/petroleum ether (3:1)
to give 6a (240 mg, 42%) as a white semisolid. Rf = 0.4 (CH2Cl2/
Z = 4, Dc = 1.520 g/cm3, µ(Mo-Kα) = 0.780 mm–1, F (000) = 560,
crystal size 0.26ϫ0.35ϫ0.87 mm, 293 K, λ(Mo-Kα)
0.71073 Å, θmin/max = 3.8/35.0°, total/unique data/R(int) = 19423/
2550/0.020, observed data = 2219 [I Ͼ 2.0σ(I)], Nref = 2550, Npar
= 65, R = 0.0264, wR2 = 0.0730.
T
=
=
9: Rf = 0.3 (CH2Cl2/petroleum ether, 1:5); m.p. 110–113 °C. FT-IR
(KBr): ν
= 2910, 2359, 1716, 1540, 1418 cm–1. 1H NMR
˜
max
(CDCl3, 400 MHz): δ = 9.09 (s, 1 H), 4.47 (s, 1 H), 3.09 (t, J =
12.34 Hz, 1 H), 2.94 (dd, J = 5.30, 3.52 Hz, 1 H), 2.68 (t, J =
3.76 Hz, 1 H), 2.64 (t, J = 3.72 Hz, 1 H), 2.10 (m, 1 H), 1.88 (m,
1 H) ppm. 13C NMR (CDCl3, 125 MHz): δ = 186.2, 53.4, 32.1,
27.6, 26.1, 24.5 ppm. MS (FAB): m/z (%) = 162 (100) [M + 2]+.
C6H8OS2 (160.26): calcd. C 44.97, H 5.03; found C 44.99, H 5.12.
10: Rf = 0.6 (CH2Cl2/petroleum ether, 1:5); m.p. 102–104 °C. FT-
hexane, 2:1). FT-IR (KBr): νmax = 3389, 2850, 1729 cm–1. 1H NMR
˜
1
IR (KBr): ν
= 2925, 1408, 1275, 1099 cm–1. H NMR (CDCl3,
(CDCl3, 300 MHz): δ = 8.03 (s, 2 H), 4.62 (br. s, 2 OH) ppm. 13C
NMR (CDCl3, 75 MHz): δ = 222.8, 214.9 ppm. MS (EI): m/z (%)
= 104 (14) [M]+, 86 (2) [M – H2O]+, 85 (35) [M – 1]+, 57 (95) [M –
CHO]+.
˜
max
300 MHz): δ = 6.28 (s, 1 H), 4.48 (s, 1 H), 3.37 (m, 4 H), 2.83 (dd,
J = 3.54, 3.96 Hz, 4 H), 2.07 (m, 2 H), 1.82 (m, 2 H) ppm. 13C
NMR (CDCl3, 75 MHz): δ = 122.5, 33.1, 31.4, 30.8, 29.8,
25.2 ppm. MS (FAB): m/z (%) = 248 (50) [M – 2]+. C9H14S4
(250.45): calcd. C 43.16, H 5.63; found C 43.20, H 5.70. Crystal
data: Empirical formula C9H14S4, formula mass 250.48, crystal sys-
tem monoclinic, space group P21/n (no.14), cell parameters: a =
11.0556(3), b = 9.2418(2), c = 12.1246(3) Å, β = 114.900(1) Å, Z =
4, Dc = 1.481 g/cm3, µ(Mo-Kα) = 0.797 mm–1, F(000) = 528, crystal
size 0.12ϫ0.19ϫ0.64 mm, T = 100 K, λ(Mo-Kα) = 0.71073 Å,
θmin/max = 32.1/37.5°, total/unique data/R(int) = 46826/5846/0.036,
observed data = 4998 [I Ͼ 2.0σ(I)], Nref = 5547, Npar = 174, R =
0.0284, wR2 = 0.0735.
3,3-Dimethoxy-2-oxopropanal 1,2-Bis[(2,4-dinitrophenyl)hydrazone]
(7):
A
solution of 3,3-dimethoxy-2-oxopropanal (500 mg,
3.5 mmol) in H2O (10 mL) was treated with (2,4-dinitrophenyl)hy-
drazine (1.42 g, 7.17 mmol) in MeOH (10 mL) and a few drops of
acetic acid. The mixture was warmed in a water bath for 25 min
and then cooled. The product that separated was filtered off,
washed and dried. It was crystallized from MeOH/chloroform to
give yellow needles (1.09 g, 62%). Rf = 0.6 (EtOAc/hexane, 1:5);
m.p. 210–215 °C (dec.). FT-IR (KBr): ν
= 3274, 2359, 1333,
˜
max
1139, 832 cm–1. 1H NMR (CDCl3, 300 MHz): δ = 13.25 (br. s, 1
H), 11.49 (br. s, 1 H), 9.17 (d, J = 2.41 Hz, 2 H), 8.51–8.42 (m, 2
H), 8.35–8.26 (m, 2 H), 7.95 (s, 1 H), 4.91 (s, 1 H), 3.53 (s, 3 H),
3.49 (s, 3 H) ppm. MS (ESI): m/z (%) = 495 (20) [M + 2]+, 433
(35), 269 (100). C17H16N8O10 (492.36): calcd. C 41.47, H 3.28, N
22.76; found C 41.48, H 3.24, N 22.82.
Bis(1,3-dithiolan-2-yl)methanone (11) and 2,2Ј;2Ј,2ЈЈ-Ter(1,3-dithio-
lan-2-yl) (12): To a stirred mixture of 4a (500 mg, 3.33 mmol) or
6a (400 mg, 3.8 mmol) and 1,2-ethanedithiol (400 mg, 3.8 mmol) in
CH2Cl2 (15 mL) was added boron trifluoride–diethyl ether
(0.5 mL) at 0–5 °C. The reaction mixture was stirred at room tem-
perature and monitored by TLC until the starting material had
disappeared. After completion of the reaction, the mixture was
neutralized by the addition of aqueous NaHCO3 (5%), washed
with H2O and extracted with CH2Cl2. The organic layer was con-
centrated under reduced pressure. The crude reaction mixture was
purified by silica gel column chromatography eluting with petro-
leum ether/CH2Cl2 (1:3), which first afforded 11 as a white crystal-
line solid (440 mg, 56%), followed by 12 as a yellow solid (330 mg,
32%).
Bis(1,3-dithian-2-yl)methanone (8), 6,7-Dihydro-5H-1,4-dithiepine-
2-carbaldehyde (9) and 2-(1,3-Dithian-2-yl)-6,7-dihydo-5H-1,4-di-
thiepine (10): To a stirred solution of 4a (500 mg, 4.1 mmol) and
boron trifluoride–diethyl ether (0.5 mL) in CH2Cl2 (50 mL), cooled
to 0 °C, was added 1,3-propanedithiol (450 mg, 4.1 mmol) drop-
wise with stirring over 15 min. The mixture was stirred at room
temperature for 3 h. With respect to the starting material, three less
polar spots (products) were generated as indicated by TLC. Aque-
ous NaHCO3 was added slowly and carefully to neutralize the mix-
ture at room temperature, which was then extracted with CH2Cl2.
The organic layer was dried (anhydrous Na2SO4), and the solvent
was then removed under reduced pressure. The crude product was
purified on silica gel by preparative TLC using petroleum ether in
chloroform (20%). Compound 8 was isolated as a white crystalline
solid (610 mg, 64%), compound 9 (57 mg, 10%) was obtained from
the less polar spot with respect to 8, and compound 10 (179 mg,
20%) was isolated from the more polar spot with respect to 8.
11: Rf = 0.4 (CH2Cl2/petroleum ether, 1:1); m.p. 142–144 °C. FT-IR
1
(KBr, ν
= 2926, 2853, 1703, 1215, 785 cm–1. H NMR (CDCl3,
˜
max
300 MHz): δ = 5.178 (s, 2 H), 3.35–3.30 (m, 8 H) ppm. 13C NMR
(CDCl3, 75 MHz): δ = 196.3, 54.4, 39.1, 29.6 ppm. MS (FAB): m/z
(%) = 237 (20) [M – 1]+, 130 (100). C7H10OS4 (238.40): calcd. C
35.26, H 4.23; found C 35.39, H 4.35.
12: Rf = 0.6 (CH2Cl2/petroleum ether, 1:1); m.p. 133–135 °C. FT-IR
(KBr): νmax = 2918, 2849, 1660, 1090, 772 cm–1. 1H NMR (CDCl3,
˜
400 MHz): δ = 5.16 (s, 2 H), 3.48 (t, J = 6.36 Hz, 2 H), 3.41 (s, 1
H), 3.37–3.34 (m, 4 H), 3.32–3.29 (q, 4 H), 3.22–3.17 (m, 2 H) ppm.
13C NMR (CDCl3, 125 MHz): δ = 63.6, 38.4, 30.0 ppm. C9H14S6
8: Rf = 0.25 (CH2Cl2/petroleum ether, 1:5); m.p. 139–142 °C. FT-
IR (KBr): ν
= 2923, 2360, 1684, 1540, 1020 cm–1. 1H NMR
˜
max
(CDCl3, 300 MHz): δ = 4.63 (s, 2 H), 3.36 (t, J = 12.99 Hz, 2 H), (314.57): calcd. C 34.36, H 4.49; found C 34.42, H 4.51. Crystal
2.61 (t, J = 3.99 Hz, 3 H), 2.56 (t, J = 4.00 Hz, 3 H), 2.08 (t, J =
2.91 Hz, 1 H), 2.04 (t, J = 2.92 Hz, 1 H), 2.00 (t, J = 2.47 Hz, 1
H), 1.87 (t, J = 2.21 Hz, 1 H) ppm. 13C NMR (CDCl3, 75 MHz):
data: Empirical formula C9H14S6, formula mass 314.56, crystal sys-
tem orthorhombic, space group Aba2 (no. 41), cell parameters: a
= 10.1586(2), b = 15.5169(4), c = 8.0488(2) Å, V = 1268.73(5) Å3,
Eur. J. Org. Chem. 2009, 1417–1426
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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