C. Fowelin, B. Schüpbach, A. Terfort
FULL PAPER
δ = 5.31 (s, 2 H, CH2), 7.53 (ddd, J = 8.5, 6.6, 0.9 Hz, 2 H, 3-H,
6-H), 7.63 (ddd, J = 8.9, 6.6, 1.3 Hz, 2 H, 2-H, 7-H), 8.07 (d, J =
8.5 Hz, 2 H, 4-H, 5-H), 8.20 (d, J = 8.9 Hz, 2 H, 1-H, 8-H), 8.51
(s, 1 H, 10-H) ppm; J(7-H,8-H) = 8.9 Hz, J(5-H,6-H) = 8.5 Hz,
3J(6-H,7-H) = 6.6 Hz. 13C NMR (100 MHz, CDCl3): δ = 29.7
(CH2), 123.4 (C-1, C-8), 125.3 (C-3, C-6), 127.0 (C-2, C-7), 127.7
(C-4a, C-10a), 128.8 (C-10), 129.5 (C-4, C-5), 130.3 (C-8a, C-9a),
131.4 (C-9), 176.3 (C=O) ppm. The signal of CCl3 could not be
detected.
ent in the anthracene system, the protecting group with-
stands prolonged attack by an excess of the 1,2-didehy-
drobenzene.
3
3
In conclusion, the benzoyl group is suitable for protect-
ing thiols against the action of the reactive species, 1,2-dide-
hydrobenzene. Some other aromatic acyl groups work simi-
larly well, but since the reagents used to introduce the
thiobenzoyl group, such as benzoyl chloride and thioben-
zoic acid (which can also be used to introduce the sulfur
atom into the molecule in the first place, see the Supporting
Information), are inexpensive reagents, they will be pre-
ferred in most cases.
S-(9-Anthryl)methyl Thiobenzoate (2f): Following the general pro-
cedure benzoyl chloride (1.88 g, 13.4 mmol) was used to obtain yel-
low crystals. Yield: 2.02 g (6.15 mmol, 92%). M.p. 119 °C. 1H
NMR (400 MHz, CDCl3): δ = 5.38 (s, 2 H, CH2), 7.44 (m, 2 H, 3-
H, 6-H), 7.50 (m, 2 H, 2-H, 7-H), 7.57 (m, 3 H, 3Ј-H, 4Ј-H, 5Ј-H),
8.00 (m, 2 H, 2Ј-H, 6Ј-H), 8.04 (m, 2 H, 4-H, 5-H), 8.30 (m, 2 H,
1-H, 8-H), 8.46 (s, 1 H, 10-H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 26.5 (CH2), 124.0 (C-1,C-8), 125.2 (C-2,C-7), 126.5 (C-3Ј, C-
5Ј), 127.3 (C-2Ј, C-6Ј), 127.9 (C-10), 128.7 (C-3, C-6), 129.3 (C-4,
C-5), 130.2 (C-4a, C-10a), 131.5 (C-8a, C-9a), 133.5 (C-4Ј), 192
(C=O) ppm. The signals of C-1Ј and C-9 could not be detected.
C22H16OS (328.43): calcd. C 80.45, H 4.91, S 9.76; found C 79.68,
H 4.95, S 9.37.
Experimental Section
General Procedure for the Preparation of 2c–k: Using N2 as an inert
gas,
a solution of 9-(mercaptomethyl)anthracene (1) (1.50 g,
6.69 mmol) in absolute THF (30 mL) was dropped into a solution
of pyridine (1.06 g, 13.4 mmol) and the acyl chloride (13.4 mmol)
in absolute THF (10 mL). After stirring at room temperature for
16 h the mixture was washed with sodium acetate buffer solution
(twice) and water. The organic solvent was removed in vacuo and
the residue was recrystallized from acetonitrile. NMR spectra were
recorded with an Avance 400 (Bruker) and a Gemini 2000 BB
(Varian). The melting points were determined with an apparatus
according to Dr. Tottoli and are not corrected. GLC was carried
out using a Perkin Elmer 8420 equipped with a 25 m methyl silicon
column (0.25 mm, 0.33 microns, pre-pressure 350 kPa N2). Elemen-
tal analyses were performed with a CHN-O-rapid (Heraeus).
S-(9-Anthryl)methyl 3,5-Dinitrothiobenzoate (2g): Following the ge-
neral procedure 3,5-dinitrobenzoyl chloride (3.09 g, 13.4 mmol)
was used. Trituration with hot acetonitrile gave an orange powder.
Yield: 2.32 g (5.54 mmol, 83%). M.p. 224 °C. 1H NMR (400 MHz,
CDCl3): δ = 5.51 (s, 2 H, CH2), 7.53 (ddd, J = 8.4, 6.6, 0.8 Hz, 2
H, 3-H, 6-H), 7.62 (ddd, J = 8.9, 6.6, 1.3 Hz, 2 H, 2-H, 7-H), 8.07
(d, J = 8.4 Hz, 2 H, 4-H, 5-H), 8.23 (d, J = 8.9 Hz, 2 H, 1-H, 8-
H), 8.50 (s, 1 H, 10-H), 9.10 (d, J = 2.1 Hz, 2 H, 2Ј-H, 6Ј-H), 9.21
4
3
(t, J = 2.1 Hz, 1 H, 4Ј-H) ppm; J(4Ј-H,2Ј-H) = 2.1 Hz, J(7-H,8-
H) = 8.9 Hz, 3J(5-H,6-H) = 8.4 Hz, 3J(6-H,7-H) = 6.6 Hz. 13C
NMR (100 MHz, CDCl3): δ = 27.4 (CH2), 122.4 (C-4Ј), 123.4 (C-
1, C-8), 125.4 (C-3, C-6), 127.0 (C-2, C-7), 127.1 (C-2Ј, C-6Ј), 128.7
(C-10), 129.5 (C-4, C-5), 130.2 (C-4a, C-10a), 131.5 (C-8a, C-9a),
139.3 (C-1Ј), 148.6 (C-3Ј, C-5Ј), 188.0 (C=O) ppm. The signal of
C-9 could not be detected. C22H14N2O5S (418.42): calcd. C 63.15,
H 3.37, N 6.70, S 7.66; found C 62.87, H 3.29, N 6.66, S 7.50.
S-(9-Anthryl)methyl Thiopivalate (2c): Following the general pro-
cedure pivaloyl chloride (1.62 g, 13.4 mmol) was used to obtain a
yellow solid. Yield: 1.73 g (5.61 mmol, 84%). Rf = 0.50 (silica gel,
1
ethyl acetate/n-hexane, 1:9 v/v). H NMR (400 MHz, CDCl3): δ =
1.28 [s, 9 H, C(CH3)3], 5.12 (s, 2 H, CH2), 7.48 (ddd, J = 8.5, 6.5,
1.1 Hz, 2 H, 3-H, 6-H), 7.56 (ddd, J = 8.9, 6.5, 1.4 Hz, 2 H, 2-H,
7-H), 8.01 (d, J = 8.5 Hz, 2 H, 4-H, 5-H), 8.20 (d, J = 8.9 Hz, 2
H, 1-H, 8-H), 8.41 (s, 1 H, 10-H) ppm; 3J(7-H,8-H) = 8.9 Hz, 3J(5-
H,6-H) = 8.5 Hz, 3J(6-H,7-H) = 6.5 Hz. 13C NMR (100 MHz,
CDCl3): δ = 26.1 (CH2), 27.3 [C(CH3)3], 47.8 [C(CH3)3], 124.0 (C-
1, C-8), 125.1 (C-3, C-6), 126.4 (C-2, C-7), 127.7 (C-10), 127.9 (C-
4a, C-10a), 129.2 (C-4, C-5), 130.1 (C-8a, C-9a), 131.5 (C-9) ppm.
C20H20OS (308.44): calcd. C 77.88, H 6.54, S 10.30; found C 77.65,
H 6.71, S 10.30.
S-(9-Anthryl)methyl 4-Methylthiobenzoate (2h): By using freshly
distilled 4-methylbenzoyl chloride (1.95 g, 12.6 mmol), a yellow so-
lid was obtained. Yield: 2.13 g (6.2 mmol, 65%). M.p. 113–115 °C.
Rf = 0.23 (n-hexane/CH2Cl2, 2:1 v/v). 1H NMR (400 MHz,
CDCl3): δ = 2.35 (s, 3 H, CH3), 5.33 (s, 2 H, CH2), 7.18 (d, J =
8.1 Hz, 2 H, 3Ј-H, 5Ј-H), 7.45 (dd, J = 7.6, 7.2 Hz, 2 H, 3-H, 6-
H), 7.54 (dd, 2 H, 2-H, 7-H), 7.87 (d, J = 8.2 Hz, 2 H, 2Ј-H, 6Ј-
H), 7.98 (d, J = 8.3 Hz, 2 H, 4-H, 5-H), 8.27 (d, J = 8.9 Hz, 2 H,
1-H, 8-H), 8.39 (s, 1 H, 10-H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 21.6 (CH3), 26.3 (CH2), 124.0 (C-1, C-8), 125.1 (C-3, C-6),
126.4 (C-2, C-7), 127.4 (C-2Ј, C-6Ј), 127.4 (C-9), 127.8 (C-10), 129.2
(C-3Ј, C-5Ј), 129.3 (C-4, C-5), 130.1 (C-4a, C-5a), 131.4 (C-8a, C-
9a), 134.0 (C-1Ј), 144.4 (C-4Ј) 191.5 (C=O) ppm. C23H18OS
(342.45): calcd. C 80.67, H 5.30, S 9.36; found C 80.61, H 5.40, S
9.55.
S-(9-Anthryl)methyl Trifluorothioacetate (2d): Trifluoroacetyl chlo-
ride (2.49 g, 18.9 mmol) was condensed into a solution of pyridine
in THF at –40 °C. The reaction was completed at room tempera-
ture according the general procedure. Yield: 1.07 g (3.34 mmol,
1
50%) of yellow crystals. M.p. 88 °C. H NMR (400 MHz, CDCl3):
δ = 5.36 (s, 2 H, CH2), 7.53 (m, J = 8.4, 6.6 Hz, 2 H, 3-H, 6-H),
7.63 (m, J = 8.9, 6.6 Hz, 2 H, 2-H, 7-H), 8.07 (m, J = 8.4 Hz, 2 H,
4-H, 5-H), 8.16 (m, J = 8.9 Hz, 2 H, 1-H, 8-H), 8.51 (s, 1 H, 10-
3
3
3
H) ppm; J(7-H,8-H) = 8.9 Hz, J(5-H,6-H) = 8.4 Hz, J(6-H,7-H)
= 6.6 Hz. 13C NMR (100 MHz, CDCl3): δ = 26.9 (CH2), 123.2 (C-
1, C-8), 125.3 (C-3, C-6), 127.2 (C-2, C-7), 129.0 (C-10), 129.5 (C-
4, C-5), 130.3 (C-4a, C-10a), 131.4 (C-8a, C-9a), 185 (C=O) ppm.
The signals of C-9 and CF3 could not be detected.
S-(9-Anthryl)methyl 4-Methoxythiobenzoate (2i): The thioester was
obtained as a yellow solid starting from 4-methoxybenzoyl chloride
(3.20 g, 20.7 mmol). Yield: 2.20 g (6.1 mmol, 65%). M.p. 127–
130 °C. Rf = 0.37 (n-hexane/CH2Cl2, 1:1 v/v). 1H NMR (400 MHz,
CDCl3): δ = 3.82 (s, 3 H, OCH3), 5.34 (s, 2 H, CH2), 6.89 (d, J =
9.0 Hz, 2 H, 3Ј-H, 5Ј-H), 7.48 (ddd, J = 8.4, 6.5, 1.1 Hz, 2 H, 3-H,
6-H), 7.56 (ddd, J = 8.8, 6.5, 1.4 Hz, 2 H, 2-H, 7-H), 7.96 (d, J =
9.0 Hz, 2 H, 2Ј-H, 6Ј-H), 8.01 (d, J = 8.4 Hz, 2 H, 4-H, 5-H), 8.30
S-(9-Anthryl)methyl Trichlorothioacetate (2e): Following the gene-
ral procedure trichloroacetyl chloride (2.44 g, 13.4 mmol) was used
to obtain yellow crystals which where treated with hot n-hexane.
Yield: 1.67 g (4.50 mmol, 67%). M.p. 68–71 °C. Rf = 0.55 (silica
1
3
gel, ethyl acetate/n-hexane, 1:9 v/v). H NMR (400 MHz, CDCl3):
(d, J = 8.9 Hz, 2 H, 1-H, 8-H), 8.43 (s, 1 H, 10-H) ppm; J(1-H,2-
1016
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Eur. J. Org. Chem. 2007, 1013–1017