(1.25 g, 4.5 mmol) in DMF (6 mL) was used for the reduction.
The product was purified on a silica gel column with n-hexane
as the mobile phase and crystallized from acetonitrile/THF.
0.24 mol) in water (25 mL) at 0 °C and the reaction vessel was
washed with acetonitrile (25 mL) in order to transfer all
diazonium salt. The reaction mixture was stirred at 25 °C for
2 h, quenched by adding aqueous 5% sodium hydrogen
carbonate (300 mL), and extracted with ethyl acetate (3 ×
250 mL). The combined organic phases were concentrated
to a volume of about 200 mL and washed with brine (3 × 200
mL). The product was isolated by recrystallization from THF/
acetonitrile. Yield: 0.83 g, 1.3 mmol 65%. Mp: 218-218.5 °C.
1H NMR: δ ) 7.48 (s, 4H) ppm. 13C NMR: δ ) 156.77, 127.18,
124.48, 123.35 ppm. EIMS: m/z [ion] (rel. int.%), 644 [M +
6]+ (39), 563 [M - Br + 4]+ (7), 535 [M - BrCO + 4]+ (15),
484 [M - 2Br + 4]+ (76), 456 [M - 2BrCO + 4]+ (13), 403 [M
- 3Br + 2]+ (94), 375 [M - 3BrCO + 2]+ (100), 324 [M - 4Br
+ 2]+ (35), 242 [M - 2Br + 2]2+ (40), 136 [M - 6BrCO]+ (5).
1
Yield: 0.21 g, 0.26 mmol, 13%. Mp 239.5-241 °C. H NMR
(DMSO-d6): δ ) 8.19 (s, 2H). 13C NMR: δ ) 152.50, 133.70,
126.80, 118.58 ppm. EIMS: m/z [ion] (rel. int. %) 802 [M +
8]+ (7), 642 [M - 2Br + 6]+ (100), 561 [M - 3Br + 4]+ (8), 533
[M - 3BrCO + 4]+ (12), 482 [M - 4Br + 4]+ (7), 373 [M -
5BrCO + 2]+ (8), 321 [M - 2Br + 3]2+ (16), 267.5 [M - 3BrCO
+ 2]2+ (6).
2,2′,3,4,4′,5,6,6′-Octabromodiphenyl Ether (BDE-204), Path-
way A. Bromine (5 mL, 98 mmol) was added to 3,5-
diaminodiphenyl ether (4) (0.43 g, 2.12 mmol) and aluminum
tribromide (2.3 g, 8.53 mmol). The reaction mixture was
refluxed for 5 h. The synthesis was continued as described
above for BDE-198 with the following crude products
obtained. Diazotization of the perbrominated crude product
(1.63 g, 1.96 mmol) was carried out with boron trifluoride
diethyl etherate (1.1 g, 7.84 mmol, 0.99 mL) in THF (10 mL)
and 3-methylbutyl nitrite (1.38 g, 11.8 mmol, 1.58 mL). The
diazonium salt obtained in an amount of 1.63 g (1.58 mmol)
was dissolved in DMF (6 mL) and iron(II)sulfate heptahydrate
(1.32 g, 4.7 mmol) was dissolved in DMF (6 mL) during the
reduction. Purification was performed without preparative
HPLC. Yield: 0.23 g, 0.28 mmol, 13%. Mp 197.5-198.5 °C. 1H
NMR: δ ) 7.85 (s, 2H) ppm. 13C NMR: δ ) 151.63, 149.62,
136.91, 129.90, 125.76, 120.17, 118.12, 115.78 ppm. EIMS:
m/z [ion] (rel. int. %) 802 [M + 8]+ (14), 642 [M - 2Br + 6]+
(100), 561 [M - 3Br + 4]+ (10), 533 [M - 3BrCO + 4]+ (13),
482 [M - 4Br + 4]+ (7), 452[M - 4Br + 4]+ (5), 373 [M -
5BrCO + 2]+ (8), 321 [M- 2Br + 3]2+ (17).
2,2′,3,4,4′,5,6,6′-Octabromodiphenyl Ether (BDE-204), Path-
way B. Bromine (5 mL, 98 mmol) was added to 3-amino-
diphenyl ether (5) (0.38 g, 2.06 mmol) and aluminum
tribromide (1.66 g, 6.22 mmol). The mixture was refluxed for
5 h. The synthesis was continued as described above for
BDE-198 with the following crude products obtained. Di-
azotization of the perbrominated crude product (1.77 g, 1.98
mmol) was performed by boron trifluoride diethyl etherate
(0.84 g, 5.94 mmol, 0.75 mL) in THF (6 mL) and 3-methylbutyl
nitrite (0.93 mg, 7.92 mmol, 1.06 mL). The diazonium salt
obtained in an amount of 1.77 g (1.78 mmol) was dissolved
in DMF (6 mL) and iron(II)sulfate heptahydrate (1.48 g, 5.3
mmol) in DMF (6 mL) was added for the reduction.
Purification was performed without preparative HPLC.
Yield: 0.51 g, 0.64 mmol, 31%.
3,3′,5,5′-Tetrabromo-4,4′-diaminodiphenyl Ether (6). Bro-
mine (2.0 mL, 40 mmol) was added to 4,4′-diaminodiphenyl
ether (2.0 g, 10 mmol) in acetic acid (50 mL) at room
temperature. The reaction was stirred at 35 °C for 5 min and
then poured into ice-cold water (200 mL). The crude product
was filtered off and purified on silica gel column with
n-hexane/ethyl acetate (6:1) as the mobile phase. Yield: 3.7
g, 7.2 mmol, 72%. Mp 165-167 °C (Lit. 169.5-170 (33).1H
NMR (CDCl3): δ ) 7.07 (s, 4H) ppm, 4.39 (s, 4H) ppm. 13C
NMR (CDCl3): δ ) 148.86, 138.62, 122.49, 108.68 ppm. EIMS:
m/z [ion] (rel. int. %), 516 [M + 4]+ (100), 435 [M - Br + 2]+
(8), 407 [M - BrCO + 2]+ (13), 355 [M - 2BrH + 2]+ (25), 266
[M - 2Br6CN2H]+ (33), 168 [M - 4BrCO]+ (9).
3,3′,4,4′,5,5′-Hexabromodiphenyl Ether (BDE-169). 3,3′,5,5′-
Tetrabromo-4,4′-diaminodiphenyl ether (1.03 g, 2.0 mmol)
was suspended in acetonitrile (150 mL). The reaction was
cooled to 0 °C and boron trifluoride diethyl etherate (0.76
mL, 6.0 mmol) was added. The reaction was stirred at 0 °C
for 10 min (during which time the suspension was dissolved)
and at room temperature for 60 min. 3-Methylbutyl nitrite
(0.80 mL, 5.2 mmol) was added at 0 °C and the reaction was
stirred for 60 min at 0 °C. Subsequently, the reaction mixture
was cooled to -25 °C and poured into a mixture of copper
(Ι) bromide (29 g, 0.2 mol) and copper (ΙΙ) bromide (54 g,
2,2′,3,3′,4,4′,5,5′-Octabromodiphenyl Ether (BDE-194).
3,3′,4,4′,5,5′-Hexabromodiphenyl ether (BDE-169) (0.64 g, 1.0
mmol) was added to a mixture of bromine (0.20 mL, 4.0
mmol) and iron powder (0.06 g, 1.0 mmol) in carbon
tetrachloride (3.5 mL). The mixture was refluxed at 70 °C for
1.5 h and the residue was washed with aqueous 5% sodium
bisulfite (5 mL), sodium hydroxide (1 M, 5 mL), water (5 mL),
aqueous 5% sodium disulfite (5 mL), and water (5 mL). Finally,
the product was recrystallized in THF/acetonitrile. Yield: 0.64
1
g, 0.80 mmol, 80%. Mp 221-222 °C. H NMR: δ ) 7.47 (s,
2H) ppm. 13C NMR: δ ) 153.72, 131.16, 125.76, 124.96, 123.60,
118.81 ppm. EIMS: m/z [ion] (rel. int. %), 802 [M - 4Br +
4]+ (6), 642 [M - 2Br + 6]+ (100), 482 [M - 4Br + 4]+ (6).
2,3′,4,5′,6-Pentabromo-3,4′-diaminodiphenyl Ether (7).
Bromine (2.6 mL, 51 mmol) was added during 10 min to
3,4′-diaminodiphenyl ether (2.0 g, 10 mmol) in acetic acid
(60 mL) at room temperature. The reaction was stirred at 35
°C for 1 h, during which time the product precipitated and
the mixture was poured into ice-cooled water (200 mL). The
crude product was filtered off and purified on silica gel
column with n-hexane/THF (4:1) as the mobile phase. Yield:
1
4.8 g, 8.1 mmol, 81%. Mp 175-177 °C. H NMR (CDCl3): δ
) 7.67 (s, 1H), 6.92 (s, 2H), 4.74 (s, 2H), 4.30 (s, 2H) ppm. 13
C
NMR (CDCl3): δ ) 148.65, 148.30, 143.45, 137.93, 134.78,
119.05, 109.06, 105.22, 104.95, 104.39. EIMS: m/z [ion] (rel.
int. %), 594 [M + 4]+ (47), 434 [M - 2Br + 2]+ (100).
2,3,3′,4,4′,5′,6-Heptabromodiphenyl Ether (BDE-191). This
compound was prepared from 2,3′,4,5′,6-pentabromo-3,4′-
diaminodiphenyl ether (1.19 g, 2.0 mmol) following the
procedure used for the synthesis of BDE-169 above. Yield:
0.83 g, 1.15 mmol 57%. Mp 228-228.5 °C. 1H NMR: δ ) 8.19
(s,1H), 7.27 (s, 2H) ppm. 13C NMR: δ ) 156.44, 149.43, 137.55,
129.66, 127.37, 124.48, 123.98, 121.98, 120.89, 118.19 ppm.
EIMS: m/z [ion] (rel. int. %), 722 [M + 6]+ (50), 560 [M - 2Br
+ 4]+ (100).
2,2′,3,3′,4,4′,5,6′-Octabromodiphenyl Ether (BDE-196). Bro-
mine (0.26 mL, 5.0 mmol) in carbon tetrachloride (5 mL) was
added to BDE-191 (0.72 g, 1.0 mmol) and iron powder (60
mg, 1.0 mmol) in carbon tetrachloride (50 mL). The mixture
was heated at 80 °C for 2 h after which bromine (0.26 mL,
5.0 mmol) in carbon tetrachloride (5 mL) was added and the
mixture was heated for an additional 2 h at 80 °C. Carbon
tetrachloride and bromine were evaporated by a gentle stream
of nitrogen at 30 °C and the product residue was purified
from polar compounds on a silica gel column with n-hexane
as the mobile phase. Finally, the product was recrystallized
in THF/acetonitrile. Yield: 0.77 g, 0.945 mmol, 94%. Mp 209-
209.5 °C. 1H NMR: δ ) 8.21 (s, 1H) ppm, 6.97 (s, 1H) ppm.
13C NMR: δ ) 153.68, 149.67, 137.55, 131.40, 129.71, 125.61,
124. 67, 123.68, 123.06, 118.39, 117.85, 116.42. EIMS: m/z
[ion] (rel. int. %), 802 [M + 8]+ (47), 642 [M - 2Br + 6]+ (100),
533 [M - 3BrCO + 4]+ (6), 482 [M - 4Br + 4]+ (7), 321 [M
- 2Br + 3]2+ (5).
9
7462 ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 41, NO. 21, 2007