Rochlin and Rappoport
suspension. The mixture was acidified with HCl to pH 3-4,
stirred for additional 1h and the precipitate formed was
filtered, washed twice with cold water and air-dried. Recrys-
tallization from EtOH gave 14 (2.18 g, 85%) as a white powder,
mp 198 °C (lit:12 198 °C); 1H NMR (CDCl3) δ (ppm): 2.38 (3H,
1.15 g (70%) of 14 as yellow crystals, mp 118-119 °C. 1H NMR
(CDCl3) δ (ppm): 7.31 (1H, ddd, 3J HH ) 7.8 Hz, 3J HF ) 9.4 Hz,
4J HH ) 2.4 Hz, H3), 7.51 (1H, m, H6), 7.63 (1H, m, H7), 8.00
3
3
4
(1H, d, J HH ) 8.2 Hz, H5), 8.02 (1H, dd, J HH ) 9.2 Hz, J HF
3
4
) 5.9 Hz, H4), 8.13 (1H, dd, J HF ) 11.5 Hz, J HH ) 2.4 Hz,
3
4
3
s), 7.23 (1H, dd, J ) 9.1 Hz, J ) 2.2 Hz), 7.47 (2H, m), 7.71
(1H, d, 4J ) 1.8 Hz), 7.99 (2H, 2d, 3J ) 8.6 Hz), 8.02 (1H, d, 3J
) 9.0 Hz), 8.37, 8.43 (2H, 2s). νmax (Nujol): 1760 (CdO), 1640
H1), 8.45 (1H, s, H10), 8.47 (1H, d, J HH ) 9.0 Hz, H8). Anal.
Calcd for C14H8BrF: C, 61.12; H, 2.93; Found: C, 61.28; H,
2.99%.
(CdC) cm-1
.
9,10-Dibr om o-2-flu or oa n th r a cen e. mp 205-206 °C (from
1
3
2-F lu or oa n th r a cen e (13). A solution of 11 (2.5 g, 11 mmol)
in AcOH (100 mL) was refluxed with 57% HI (11 mL) for 60
h. The mixture was cooled to room temperature and poured
into water (300 mL). The precipitate that formed was filtered
EtOH); H NMR (CDCl3) δ (ppm): 7.41 (1H, ddd, J HH ) 9.7
3 4
Hz, J HF ) 9.4 Hz, J HH ) 2.4 Hz, H3), 7.63 (2H, m, H6,H7),
3
4
8.20 (1H, dd, J HF ) 11.0 Hz, J HH ) 2.5 Hz, H1), 8.53 (2H, m,
H5, H8), 8.61 (1H, dd, 3J HH ) 9.7 Hz, 4J HF ) 5.9 Hz, H4). Anal.
Calcd for C14H7Br2F: C, 47.50; H, 1.99; Found: C, 47.74; H,
1.94%.
1
and dried. According to H NMR, it is a 7:3 mixture of 13 to
2-fluoro-9,10-dihydroanthracene. A small excess of iodine (0.88
g, 3.5 mmol) was added to the solid in refluxing toluene (150
mL) until the 9,10-dihydro derivative was disappeared accord-
ing to TLC. The mixture was cooled to room temperature,
washed successively with 5% NaHCO3 (150 mL), saturated
Na2S2O3 solution (150 mL) and water (150 mL) and evaporated
to dryness under reduced pressure. The yellow residue was
recrystallized from AcOH giving 13 (1.85 g, 86%) as off-white
1-[9′-(2′-Meth oxya n th r yl)]-2,2-d im esityleth en ol (2). To
a solution of 5 (1.0 g, 3.5 mmol) in dry ether (20 mL), 2.5 M
BuLi in hexane (1.5 mL, 3.75 mmol) was added at 0 °C. The
mixture was stirred for 30 min at 0 °C, and a solution of
dimesitylketene10 (1.0 g, 3.6 mmol) in dry THF (40 mL) was
added over 15 min. The mixture was refluxed overnight,
poured into ice (200 g)/concentrated HCl (10 mL), extracted
with chloroform (3 × 50 mL) and the combined organic phase
was dried (MgSO4) and evaporated. The residue was purified
by column chromatography on silica gel using consecutively
petroleum ether and 70:30 petroleum ether - chloroform as
the eluents, giving 2 (525 mg, 31%) as an orange solid (1H
NMR data given in Table 3). An analytical sample was
crystallized from 2-propanol giving the 1:1 adduct 2‚i-PrOH
as orange crystals, mp 104 °C (dec). Anal. Calcd for C38H42O3:
C, 83.48; H, 7.74. Found: C, 83.76; H, 7.59%.
1
crystals, mp 212 °C (lit:26 212 °C); H NMR (CDCl3) δ (ppm):
7.27 (1H, ddd, 3J HH ) 3J HF ) 8.9 Hz, 4J HH ) 2.5 Hz), 7.47 (2H,
3
4
m,), 7.57 (1H, dd, J HF ) 10.2 Hz, J HH ) 2.4 Hz), 7.99 (3H,
m), 8.35, 8.43 (2H, 2s).
2-Acet oxy-9-b r om oa n t h r a cen e (15). A solution of 2-
acetoxyanthracene 14 (1.7 g, 7.2 mmol) in hot AcOH (50 mL)
was cooled rapidly to 20 °C. To the suspension thus formed, a
solution of bromine (0.85 mL, 16.5 mmol) in AcOH (15 mL)
was added slowly over 1.5 h. The reaction was monitored by
TLC using 2:1 CHCl3:petroleum ether eluent (Rf: 14, 0.15; 15,
0.75; 9,10-dibromo derivative, 0.9). The addition of bromine
was stopped when only a small amount of 14 had remained
in the mixture but accumulation of the dibromo derivative was
still insignificant. The suspension then turned immediately
into a clear solution which was poured into water (250 mL).
The yellow, fine suspension that was formed was stirred with
heating at 60-70 °C for 2 h. The precipitate that formed was
filtered, washed thoroughly with water, dried in vacuo, and
purified by flash chromatography, giving a mixture of 15 and
the 9,10-dibromo derivative (0.09 g) as a first fraction and then
2.1 g of 15. Recrystallization from AcOH gave pure 15 (1.77 g,
78%) as yellow needles, mp 110 °C. 1H NMR (CDCl3) δ (ppm):
2.41 (3H, s, CH3), 7.28 (dd, H3 partly overlaps the CHCl3
1-[9′-(2′-F lu or oa n th r yl)]-2,2-d im esityleth en ol (3). The
enol was prepared as described above for 2 from 6 (1.05 g, 3.8
mmol), 2.5M BuLi (1.5 mL, 3.8 mmol) and dimesitylketene
(1.09 g, 3.9 mmol). 635 mg (35%) of a yellow solid were
obtained. The sample used in the experiments was crystallized
from 2-propanol giving the 1:1 adduct 3‚i-PrOH as yellow
1
crystals, mp 136 °C (dec). H and 19F NMR data are in Table
3. Anal. Calcd for C37H39FO2: C, 83.11; H, 7.35. Found: C,
83.41; H, 7.27%.
1-[9′-(2′-F lu or oa n th r yl)]-2,2-d im esitylvin yl Aceta te (4).
A solution of 3 (300 mg, 0.6 mmol) in pyridine (10 mL)-Ac2O
(3 mL) was refluxed for 2 h and then poured into cold water
(100 mL). The mixture was acidified with HCl to pH 3-4,
extracted with ether (3 × 50 mL) and the combined organic
layer was dried (MgSO4) and evaporated. Crystallization of
the solid residue from petroleum ether yielded 251 mg (81%)
of 4, mp 194 °C. The 1H NMR spectrum is in Table 3. Anal.
Calcd for C36H33FO2: C, 83.69; H, 6.44. Found: C, 83.94; H,
6.28%.
Cr ysta llogr a p h ic P a r a m eter s of 4. The material crystal-
lized in the C2/c space group with eight molecules in a cell of
dimensions a ) 33.431 Å, b ) 11.286 Å, c ) 15.600 Å, â )
107.05° and V ) 5627 Å3. Fcalcd ) 1.22 g cm-3, µ(Mo KR) )
0.73 cm-1, no. of unique reflections ) 4160, no. of reflections
with I G 2σI ) 2629. R ) 0.070, Rw ) 0.082.
3
signal), 7.50, 7.62 (2H, 2m, H6,H7), 7.99 (1H, d, J ) 7.7 Hz,
3
4
H5), 8.02 (1H, d, J ) 9.1 Hz, H4), 8.22 (1H, d, J ) 2 Hz, H1),
8.44 (1H, s, H10), 8.48 (1H, d, 3J ) 8.9 Hz, H8). Anal. Calcd for
C
16H11BrO2: C, 60.98; H, 3.52; Found: C, 61.19; H, 3.47%.
9,10-Dibr om o-2-a cetoxya n th r a cen e. 1H NMR (CDCl3) δ
3
4
(ppm): 2.42 (3H, s, CH3), 7.40 (1H, dd, J ) 9.5 Hz, J ) 2.2
Hz, H3), 7.64 (2H, m, H6,H7), 8.31 (1H, d, 4J ) 2.2 Hz,H1), 8.56
3
(2H, m, H5,H8), 8.63 (1H, d, J ) 9.5 Hz, H4).
9-Br om o-2-m eth oxya n th r a cen e (5). A suspension of 15
(1.77 g, 5.6 mmol) in 5% aqueous NaOH (50 mL) was stirred
at 50-60 °C for 20 min, until a greenish-yellow fluorescent
solution was formed. The solution was cooled to room temper-
ature, dimethyl sulfate (1 mL) was added, stirring continued
for about 8-10 h and the orange precipitate which was
gradually formed was filtered, washed with water and recrys-
tallized from EtOH, yielding pure 5 (1.32 g, 82%) as orange
crystals, mp 116 °C. 1H NMR (CDCl3) δ (ppm): 4.02 (3H, s,
Ack n ow led gm en t. We are indebted to Prof. Silvio
E. Biali for helpful suggestions and discussions, to Dr.
Shmuel Cohen for the crystallographic determination,
to Dr. Shulamith Levin for help with the chiral separa-
tion and to the Israel Science Foundation for support.
3
4
OCH3), 7.17 (1H, dd, J ) 9.1 Hz, J ) 2.3 Hz, H3), 7.43 (1H,
3
m, H6), 7.57 (1H, m, H7), 7.66 (1H, bs, H1), 7.86 (1H, d, J )
Su p p or tin g In for m a tion Ava ila ble: Figure S1 of the
stereoview and Tables S1-5 of the details of the crystal-
lographic technique, of bond lengths and angles and of position
and thermal parameters of 4. This material is available free
9.1 Hz, H4), 7.94 (1H, d, 3J ) 8.4 Hz, H5), 8.32 (1H, s, H10),
3
8.44 (1H, d, J ) 8.9 Hz, H8). Anal. Calcd for C15H11BrO: C,
62.74; H, 3.86; Found: C, 62.51; H, 3.99%.
9-Br om o-2-flu or oa n th r a cen e (6). 13 (1.17 g, 6 mmol) was
brominated by a procedure similar to that described for 15,
yielding after chromatography and crystallization from AcOH
J O020497Q
226 J . Org. Chem., Vol. 68, No. 2, 2003