B. P. Czech et al. / Tetrahedron 63 (2007) 1360–1365
1363
3. Experimental
powder (60 mg, 19%) with mp 217–218 ꢀC. 1H NMR
(CDCl3): d 1.35–1.45 (m, 12H), 1.62 (s, 24H), 1.73 (m,
8H), 3.87 (t, J¼6.4 Hz, 8H), 6.75 (d, J¼6.7 Hz, 8H), 7.08
(s, 8H), 7.11 (m, 8H). 13C NMR (CDCl3): d 26.0, 29.1,
29.2, 30.8, 41.8, 67.7, 113.7, 126.2, 127.7, 142.8, 147.8,
156.8. Anal. Calcd for C66H84O4$EtOAc: C, 81.44; H,
8.70. Found: C, 81.80; H, 9.13.
3.1. General
Melting points were determined with a Fisher–Johns melting
point apparatus. NMR spectra were obtained with 200 MHz
Varian or Bruker spectrometers. Spectra were taken in
CDCl3 and chemical shifts are reported in parts per million
(ppm) downfield from TMS.
3.2.3. Corral 10. A mixture of bisphenol 1 (475 mg,
1.40 mmol), dibromide 8 (1.00 g, 1.40 mmol), K2CO3
(0.40 g, 2.80 mmol), and acetone (600 mL) was stirred at re-
flux for 9 days. The workup was identical to that given above
for corral 9. A white powder (195 mg, 14%) with mp 187–
3.2. Synthesis
Unless specified otherwise, reagent-grade reactants and
solvents were used as received from chemical suppliers.
Bisphenol 1 and Cs2CO3 were obtained from TCI America
and Chemetall GMBH (marketed in the USA by CM
Chemical Products, Inc. of Berkeley Heights, New Jersey),
respectively. Both Cs2CO3 and K2CO3 were dried overnight
in an oven and freshly powdered before use.
1
191 ꢀC was obtained. H NMR (CDCl3): d 1.30–1.40 (m,
16H), 1.62 (s, 24H), 1.73 (m, 8H), 3.90 (t, J¼6.4 Hz, 8H),
6.75, (d, J¼8.9 Hz, 8H), 7.08 (s, 8H), 7.11 (m, 8H). 13C
NMR (CDCl3): d 25.8, 29.2, 30.8 (predicted to be two peaks
by calculation), 41.8, 67.7, 113.7, 126.2, 127.7, 142.7, 147.8,
156.8. Anal. Calcd for C64H80O4$0.1EtOAc: C, 83.94; H,
8.85. Found: C, 83.63; H, 8.75.
THF was distilled from sodium metal with benzophenone
ketyl as indicator. Acetone was distilled from and stored
over anhydrous K2CO3. DMF was distilled from BaO or
CaH2 and stored over 4 A molecular sieves. DMSO was
˚
stored over 4 A molecular sieves.
3.2.4. Bisphenol 11. A 500-mL, 3-necked flask was charged
with a,a,a0,a0-tetramethyl-1,4-benzenedimethanol (50.0 g,
0.26 mol) and 2,6-dimethylphenol (317.2 g, 2.6 mol). The
reaction vessel was fitted with a mechanical stirrer and
heated to 80 ꢀC. Upon melting of the reactants, stirring
was initiated and HCl gas was bubbled directly into the re-
action mixture through a 1/4-inch glass tube. (The HCl gas
was generated by slowly dripping concentrated HCl into
concentrated H2SO4.) The reaction mixture was saturated
with HCl for 30 min at which point HCl introduction was
terminated. Stirring at 80 ꢀC was continued for 3 h and the
mixture was poured into water (500 mL). Repeated washing
of the crude oil with water gave a light brown solid. Recrys-
tallization of the solid from EtOH gave 11 (76.0 g, 73%) as
very large prisms. 1H NMR (CDCl3): d 1.62 (s, 12H), 2.19 (s,
12H), 4.46 (s, 2H), 6.83 (s, 4H), 7.11 (s, 4H). 13C NMR
(CDCl3): d 16.1, 30.8, 41.6, 122.2, 126.1, 126.9, 142.4,
147.8, 149.9. Anal. Calcd for C28H34O2: C, 83.54; H, 8.51.
Found: C, 83.79; H, 8.50.
˚
3.2.1. Dibromides 7 and 8. A mixture of bisphenol 1
(2.00 g, 5.70 mmol), the 1,u-dibromoalkane (29.0 mmol),
K2CO3 (1.57 g, 11.4 mmol), and acetone (50 mL) was
refluxed for 5 h and evaporated in vacuo. To the residue,
CH2Cl2 was added and the mixture was filtered. The filtrate
was evaporated in vacuo to provide a pale yellow oil, which
was purified by flash chromatography on silica gel with
EtOAc–hexanes (3:17) as eluent.
Dibromide 7: obtained in 81% yield as a white solid with
1
mp 69–70 ꢀC. H NMR (CDCl3): d 1.40–1.45 (m, 12H),
1.62 (s, 12H), 1.75 (m, 4H), 1.85 (m, 4H), 3.40 (t,
J¼6.8 Hz, 4H), 3.90 (t, J¼6.4 Hz, 4H), 6.77 (d, J¼6.7 Hz,
4H), 7.08 (s, 4H), 7.12 (d, J¼6.7 Hz, 4H). 13C NMR
(CDCl3): d 25.9, 28.1, 28.5, 29.2, 30.9, 32.7, 33.9, 41.8,
67.6, 113.7, 126.2, 127.7, 142.7, 147.8, 156.8. Anal. Calcd
for C38H52O2Br2: C, 65.31; H, 7.51. Found:C, 65.24;H, 7.71.
3.2.5. Dibromides 12 and 13. A mixture of bisphenol 1
(10.00 g, 29 mmol), the 1,u-dibromoalkane (0.20 mol),
freshly ground K2CO3 (20 g), acetone (20 mL), and water
(8 mL) was refluxed for 48 h and evaporated in vacuo. To
the residue, CH2Cl2 and water were added. The organic layer
was separated, washed with water, dried over MgSO4, and
evaporated in vacuo. Chromatography of the residue on
silica gel first with hexane to remove the residual 1,u-
dibromoalkane and then with CH2Cl2 gave the product.
Dibromide 8: obtained in 84% yield as a white solid with
mp 59–61 ꢀC. 1H NMR (CDCl3): d 1.30–1.40 (m,
16H), 1.66 (s, 12H), 1.75 (m, 4H), 1.85 (m, 4H), 3.40 (t,
J¼6.8 Hz, 4H), 3.91 (t, J¼6.4 Hz, 4H), 6.77 (d, J¼6.8 Hz,
4H), 7.09 (s, 4H), 7.13 (d, J¼6.8 Hz, 4H). 13C NMR (CDCl3):
d 26.0, 28.1, 28.7, 29.2, 29.3, 30.9, 32.8, 34.0, 41.8, 67.4,
113.7, 126.2, 127.7, 142.7, 147.8, 156.9. Anal. Calcd for
C40H56O2Br2: C, 66.09; H, 7.77. Found: C, 66.41; H, 7.60.
Dibromide 12: obtained 59% yield of white solid with
1
mp 152–154 ꢀC. H NMR (CDCl3): d 1.62 (s, 12H), 1.90–
3.2.2. Corral 9. A mixture of bisphenol 1 (124 mg,
0.36 mmol), dibromide 7 (250 mg, 0.36 mmol), K2CO3
(149 mg, 1.10 mmol), and acetone (300 mL) was stirred at
reflux for 6 days and evaporated in vacuo. To the residue,
CH2Cl2 (50 mL) was added and the mixture was filtered.
The filtrate was washed with 10% HCl (3ꢁ25 mL), 1 M
NaOH (3ꢁ25 mL), and distilled water (25 mL). After drying
over MgSO4 and evaporation in vacuo, the resultant white
residue was purified by flash chromatography on silica gel
with EtOAc–hexanes (3:17) as eluent to provide a white
2.20 (m, 8H), 2.20 (s, 12H), 3.51 (t, J¼6.4 Hz, 4H), 3.76
(t, J¼6.6 Hz, 4H), 6.83 (s, 4H), 7.09 (s, 4H). Anal. Calcd
for C36H48O2Br2: C, 64.29; H, 7.19. Found: C, 64.35;
H, 7.35.
Dibromide 13: obtained 44% yield of white solid with
1
mp 131–134 ꢀC. H NMR (CDCl3): d 1.62 (s, 12H), 1.60–
2.00 (m, 12H), 2.21 (s, 12H), 3.45 (t, J¼6.3 Hz, 4H),
3.74 (t, J¼6.7 Hz, 4H), 6.83 (s, 4H), 7.09 (s, 4H). Anal. Calcd
for C38H52O2Br2: C, 65.12; H, 7.48. Found: C, 65.17; H, 7.47.