Facile synthesis of 6-iodo-2,2′-dipivaloyloxy-1,1′-binaphthyl, a key intermediate of high reactivity for selective palladium-catalyzed monofunctionalization of the 1,1′-binaphthalene core

Article abstract of DOI:10.1016/j.tetlet.2010.05.022

A high-yielding procedure for selective monoiodination of 2,2′-dihydroxy-1,1′-binaphthyl (BINOL) is reported. 6-Iodo-2,2′-dipivaloyloxy-1,1′-binaphthyl, obtained in three steps starting from BINOL in 88% overall yield, proved to be a highly efficient substrate in various palladium-catalyzed coupling (Stille, Heck, Sonogashira, and Suzuki coupling) and carbonylation reactions compared to the analogous 6-bromo derivative.

Full text of DOI:10.1016/j.tetlet.2010.05.022

Tetrahedron Letters 51 (2010) 3629–3632
Contents lists available at ScienceDirect
Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
0
0
Facile synthesis of 6-iodo-2,2 -dipivaloyloxy-1,1 -binaphthyl, a key
intermediate of high reactivity for selective palladium-catalyzed
0
monofunctionalization of the 1,1 -binaphthalene core
a
a
b
b
a
a,*
Csaba Fehér , Béla Urbán , László Ürge , Ferenc Darvas , József Bakos , Rita Skoda-Földes
a
University of Pannonia, Institute of Chemistry, Department of Organic Chemistry, H-8201 Veszprém, PO Box 158, Hungary
ThalesNano Inc., H-1031 Budapest, Záhony u. 7., Hungary
b
a r t i c l e i n f o
a b s t r a c t
0
0
Article history:
A high-yielding procedure for selective monoiodination of 2,2 -dihydroxy-1,1 -binaphthyl (BINOL) is
Received 22 March 2010
Revised 23 April 2010
Accepted 7 May 2010
Available online 13 May 2010
0
0
reported. 6-Iodo-2,2 -dipivaloyloxy-1,1 -binaphthyl, obtained in three steps starting from BINOL in 88%
overall yield, proved to be a highly efficient substrate in various palladium-catalyzed coupling (Stille,
Heck, Sonogashira, and Suzuki coupling) and carbonylation reactions compared to the analogous 6-
bromo derivative.
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
Iodination, 1,1 -Binaphthyl derivatives
0
Palladium
Coupling reactions
Carbonylation
0
0
7
Optically active 2,2 -dihydroxy-1,1 -binaphthyl (BINOL) and its
derivatives have attracted significant interest due to their applica-
tion as ligands in enantioselective catalytic reactions.1 The main
drawback of these homogeneous catalytic systems is in the difficulty
of recovery and recycling of the expensive chiral catalysts. Accord-
ingly, several creative synthetic strategies toward polymer-, dendri-
catalytic system after heating for 36 h at 130 °C. In spite of this, re-
ports on the synthesis of the potentially more reactive monoiodo
derivatives are scarce. A 3-iodo derivative was prepared in 44% over-
all yield starting from BINOL via de-iodination of an intermediate
0
0
0
8
3,3 -diiodo-2,2 -dimethoxy-1,1 -binaphthalene. Another approach
0
involves halogen–lithium, lithium–halogen exchange of a 6 -substi-
2
16
mer-, and silica-supported BINOL-type ligands were developed.
tuted 6-monobromo compound.
Many of these use an halogenated BINOL derivative as the starting
As part of our ongoing research on palladium-catalyzed reactions
3
–6
17
material
reaction of such compounds as the key step.
erature, BINOL and its derivatives can be halogenated selectively at
and often incorporate a palladium-catalyzed coupling
of aryl/alkenyl halides, the functionalization of 6-bromo-2-hydro-
7–10
0
0
7
According to the lit-
xy-2 -pivaloyloxy-1,1 -binaphthyl via aminocarbonylation was at-
tempted. As we observed a sluggish reaction, we decided to explore
the possibility of selective monoiodination of the binaphthyl core in
order to obtain a more reactive substrate.
0
11
0
12
0
13
the 6,6 -, 3,3 -, and 5,5 - positions. However, there are fewer re-
ports on selective monohalogenation of similar compounds. 6-
Mono-bromo-BINOL derivatives were synthesized via direct bro-
Recently, several direct iodinations of activated aromatic com-
pounds were reported in the presence of a wide variety of reagents,
5
0
0
14
mination of BINOL or 2,2 -diethoxy-1,1 -binaphthalene, and,
more efficiently, through mono-ester formation between BINOL
and pivaloyl chloride followed by bromination.7 At the same time,
palladium-catalyzed coupling reactions of the bromo derivatives
can be carried out efficiently usually only under harsh reaction con-
1
8
19
20
21
such as NaIO
4
/KI/NaCl, NaClO
2
/NaI/HCl, KIO
3
/KI/HCl, PyꢀICl,
,15
22
and IPy
2
BF
4
.
All of these reagents gave unsatisfactory results in
the iodination of either BINOL (1) or 2-hydroxy-2 -pivaloyloxy-
1,1 -binaphthyl (2). Interestingly, the solid-phase reaction of 2 with
0
0
0
23
ditions. As an example, Heck reaction of 6-bromo-2-hydroxy-2 -
pivaloyloxy-1,1 -binaphthyl and butyl acrylate afforded the cou-
AgNO
3
/I ,
2
which had been reported to be a very effective method
0
for the iodination of both activated and deactivated aromatic com-
pling product in 87% yield in the presence of the Pd(OAc)
2
—(o-Tol)
3
P
pounds, led to the selective formation of the 6-nitro derivative 3 in
2
4
a yield of 57% after optimization (Scheme 1). The presence of iodo
derivatives was not detected in the reaction mixture. The position of
*
Corresponding author. Tel.: +36 88 624719; fax: +36 88 624469.
E-mail addresses: skodane@almos.uni-pannon.hu, skodane@almos.vein.hu (R.
Skoda-Földes).
1
1
the nitro group was proved using 2D NMR techniques ( H– H COSY,
HSQC, and HMBC).
0
040-4039/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2010.05.022

3
630
C. Fehér et al. / Tetrahedron Letters 51 (2010) 3629–3632
It should be mentioned that the attempted iodination of BINOL
1) resulted in a complex mixture of several unidentified side prod-
ucts and no conversion of 2,2 -dipivaloyloxy-1,1 -binaphthyl was
observed under the same reaction conditions.
(
OH
OH
0
0
The reactivity of 5 was examined in various palladium-cata-
lyzed reactions (Scheme 2, Table 1). As a comparison, carbonyl-
1
0
0
ation/coupling reactions of 6-bromo-2,2 -dipivaloyloxy-1,1 -
2
8,29
(
CH ) CCOCl
binaphthyl (6), obtained by pivaloylation
2
of known 6-bromo-
3
3
0
0
7
-hydroxy-2 -pivaloyloxy-1,1 -binaphthyl, were carried out under
Et
3
N, CH
0 o
7%
3
CN
the same conditions. The reactions were followed by GC and the
formation of the products confirmed by GC–MS. The reactions
were completely selective in each case, besides the carbonyl-
ation/coupling products, no other derivatives were obtained. The
reaction conditions for the conversion of 5 were not optimized.
In the aminocarbonylation using morpholine as the nucleophilic
reagent, a marked difference in the reactivities of 5 (Table 1, entry
C
9
O N
2
AgNO3/I2
7%
OH
OPiv
OH
OPiv
5
1
) and 6 (entry 2) was observed. A poor conversion of 6 was ob-
tained even after 12 h. As expected, under carbonylation condi-
tions, the formation of 7a was accompanied by double
2
3
a
carbonylation leading to ketoamide 7b, even at atmospheric CO
pressure, in both cases.
Compound 5 was also found to be a superior substrate in Heck
and Sonogashira reactions (entries 3–10). The reactivity difference
between 5 and 6 is especially evident when using less active re-
agents, such as 2-methyl-3-butyn-2-ol in the Sonogashira coupling
Ag SO4/I2
2
17b
EtOH, r.t.
95%
I
I
(
entries 8–10).
(
3
CH3) CCOCl
OH
OPiv
OPiv
Although Sonogashira and Stille reactions of 6 gave the ex-
OPiv Et N,CH CN
3
3
pected products in reasonable to excellent yields, respectively (en-
tries 6 and 12), total conversion of the 6-iodo derivative 5 was
observed even upon reducing the reaction temperature (entries 7
and 13).
0 o
C
96%
4
5
Scheme 1. Synthesis of 6-monosubstituted BINOL derivatives 3–5.
The only example where 5 and 6 gave identical results under
the conditions used was in the Suzuki coupling with PhB(OH)
tries 15 and 16).
2
(en-
25
Fortunately, iodination of 2 with Ag
reaction affording 4 in 95% yield (Scheme 1). The structure of 4
was proved by 2D NMR methods.
2
SO
4
/I
2
gave a selective
2
6
It should be mentioned that derivative 4 was found to be an al-
most equally reactive substrate in these couplings, but the forma-
tion of side products was observed. Clarification of the effect of
Electron-deficient aryl halides are usually more reactive sub-
strates in palladium-catalyzed coupling reactions because of the
more facile oxidative addition of these compounds to the nucleo-
philic Pd(0) complex. In order to obtain a substrate with high reac-
tivity, compound 4 was converted into the dipivaloyloxy derivative
0
protecting groups on the reactivity of 6-halogeno-2,2 -dihydroxy-
0
1
,1 -binaphthyl derivatives as well as exploration of the side reac-
tions observed in couplings of 4 is in progress.
0
0
In summary, 6-iodo-2,2 -dipivaloyloxy-1,1 -binaphthyl (5) was
2
7
28
0
0
synthesized in high yield starting from 2,2 -dihydroxy-1,1 -binaph-
5
using a standard procedure.
X
OPiv
OPiv
5
6
X=I
X=Br
[
Pd]
[Pd]
[Pd]/CuI
R
[Pd]
[Pd]
CH2=CHCO2Me
Et3N
PhB(OH)2
O
NH, CO
Et3N
CH2=CHSnBu3
2
K CO3
R
O
MeO C
Ph
2
N
n
O
OPiv
OPiv
OPiv
OPiv
OPiv
OPiv
OPiv
OPiv
OPiv
OPiv
7
a
n=1
n=2
9
R=Ph
11
8
12
7
b
10 R=C(CH3)2OH
Scheme 2. Palladium-catalyzed reactions of 6-iodo-(5) and 6-bromo-(6) derivatives of BINOL.

C. Fehér et al. / Tetrahedron Letters 51 (2010) 3629–3632
3631
Table 1
Palladium-catalyzed coupling and carbonylation reactions of 5 and 6
Entry
1b
Products
Substrate
Temperature (°C)
Time (h)
Yielda (%)
7a + 7b
7a + 7b
8
8
9
5
6
5
6
5
6
5
5
6
6
5
6
5
6
5
6
100
100
100
100
60
2
92 (7a/7b = 94/6)
b
h
2
3
4
2 (12)
16 (23) (7a/7b = 90/10)
c
2
2
100
21
c
d
5
2
2 (8)
0.5
2
100
50 (81)
d
h
6
9
9
60
rt
d
7
100
100
82
e
8
9
10
10
10
11
11
11
11
12
12
100
100
120
100
100
60
60
60
60
e
8
8
2
e
1
0
96
f
f
f
f
11
12
13
14
100
60 (100)
h
2 (4)
2
2 (6)
2
100
21 (31)
h
g
g
1
5
92
93
1
6
2
a
b
c
Determined by GC.
5
5
5
1
2
5
mol % Pd(OAc)
mol % Pd(OAc)
2
, 10 mol % PPh
, 10 mol % PPh
) , 5 mol % CuI, substrate/phenylacetylene/Et
3 2 3
3
, substrate/morpholine/Et
3
N = 1/5/2 in DMF under a CO atmosphere.
2
3
, substrate/methyl acrylate/Et
3
N = 1/2.5/2 in DMF.
N = 1/2.5/2 in DMF.
, 10 mol % CuI, substrate/2-methyl-3-butyn-2-ol/Et N = 1/2.5/2 in DMF.
, substrate/CH @CHSnBu = 1/1.1, in DMF.
substrate/ PhB(OH) /K CO = 1/2/5 in THF/H
d
e
f
mol % PdCl
2
(PPh
0 mol % PdCl
2
(PPh
3
)
2
3
mol % Pd(PPh
mol % Pd(PPh
3
)
)
4
2
3
g
h
3
4
2
2
3
2
O (1:1).
Yield obtained after heating the reaction mixture for the total time given in parenthesis in the previous column.
thyl. The method led to the product in three selective steps using
non-expensive reagents. Compound 5 was shown to be a highly
reactive substrate for palladium-catalyzed functionalization under
very mild reaction conditions.
18. Emmanuvel, L.; Shukla, R. K.; Sudalai, A.; Gurunath, S.; Sivaram, S. Tetrahedron
Lett. 2006, 47, 4793–4796.
19. Lista, L.; Pezzella, A.; Napolitano, A.; d’Ischia, M. Tetrahedron 2008, 64, 234–
239.
20. Adimurthy, S.; Ramachandraiah, G.; Ghosh, P. K.; Bedekar, A. V. Tetrahedron
Lett. 2003, 44, 5099–5101.
2
1. Aneja, R.; Vangapandu, S. N.; Lopus, M.; Viswesarappa, V. G.; Dhiman, N.;
Acknowledgments
Verma, A.; Chandra, R.; Panda, D.; Joshi, H. C. Biochem. Pharmacol. 2006, 72,
4
15–426.
2. Shimada, T.; Suda, M.; Nagano, T.; Kakiuchi, K. J. Org. Chem. 2005, 70, 10178–
0181.
3. Yusubov, M. S.; Tveryakova, E. N.; Krasnokutskaya, E. A.; Perederyna, I. A.;
Zhdankin, V. V. Synth. Commun. 2007, 37, 1259–1265.
4. A mixture of I
(254 mg, 1 mmol) and AgNO (170 mg, 1 mmol) was ground in
2 3
2
2
2
The authors thank the Hungarian National Science Foundation
OTKA NK71906) and the National Office for Research and Technol-
ogy (NKFP 07 A2 FLOWREAC) for financial support.
1
(
a mortar for 1 min, and then 2 (185 mg, 0.5 mmol) was added. The resulting
homogeneous mixture was ground for 10 min, and then after a 2 min break,
grinding was continued for an additional 30 min. The organic compounds were
References and notes
1.
2.
3.
4.
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extracted with Et O (3 ꢁ 10 ml). After evaporation of the solvent, the product 3
2
was purified by column chromatography (silica, n-hexane/EtOAc = 3/1) and
obtained in 57% yield. Selected spectroscopic data for 3: 1H NMR (400 MHz,
Hesemann, P.; Moreau, J. J. E.; Yixiang, C. Tetrahedron: Asymmetry 2002, 13,
CDCl , d): 8.74 (d, J = 2.3 Hz, 1H); 8.06 (d, J = 8.9 Hz, 1H); 8.01 (d, J = 9.0 Hz, 1H);
3
6
07–613.
7.95 (dd, J = 9.3 Hz, 2.3 Hz, 1H); 7.94 (dd, J = 9.3 Hz, 1.2 Hz, 1H); 7.49 (ddd,
5
6
.
.
Jayaprakash, D.; Sasai, H. Tetrahedron: Asymmetry 2001, 12, 2589–2595.
(a) Pathak, K.; Bhatt, A. P.; Abdi, S. H. R.; Kureshy, R. I.; Khan, N. H.; Ahmad, I.;
Jasra, R. V. Tetrahedron: Asymmetry 2006, 17, 1506–1513; (b) Bhatt, A. P.;
Pathak, K.; Jasra, R. V.; Kureshy, R. I.; Khan, N. H.; Abdi, S. H. R. J. Mol. Catal. A
J = 9.3 Hz, 6.8 Hz, 1.2 Hz, 1H); 7.40 (d, J = 9.0 Hz, 1H); 7.33 (ddd, J = 8.4 Hz,
6.8 Hz, 1.2 Hz, 1H); 7.32 (d, J = 8.9 Hz, 1H); 7.17 (dd, J = 8.4 Hz, 1.2 Hz, 1H); 7.10
(d, J = 9.3 Hz, 1H); 5.50 (br s, 1H); 0.74 (s, 9H). 13C NMR (100.62 MHz, CDCl , d):
3
177.7; 155.3; 148.5; 143.9; 136.7; 133.1; 132.4; 132.3; 131.5; 128.6; 127.9;
127.3; 126.5; 126.0; 125.0; 124.8; 121.9; 121.4; 120.5; 120.2; 115.0; 38.8;
2
006, 244, 110–117.
+
7
8
.
.
Hocke, H.; Uozumi, Y. Tetrahedron 2003, 59, 619–630.
Meng, Y.; Slaven IV, W. T.; Wang, D.; Liu, T. J.; Chow, H. F.; Li, C. J. Tetrahedron:
Asymmetry 1998, 9, 3693–3707.
26.5. MS (m/z (rel. int.)): 415 (M )(15); 331(34); 314(9); 255(9); 226(13);
85(19); 57(100).
25. Zhang, H.; Wang, S.; Li, Y.; Zhang, B.; Du, C.; Wan, X.; Chen, Y. Tetrahedron 2009,
65, 4455–4463.
9
.
(a) Hocke, H.; Uozumi, Y. Tetrahedron 2004, 60, 9297–9306; (b) Wu, L.; Zheng,
L.; Zong, L.; Xu, J.; Cheng, Y. Tetrahedron 2008, 64, 2651–2657; (c) Yuan, X. Y.; Li,
H. Y.; Hodge, P.; Kilner, M.; Tastard, C. Y.; Zhang, Z. P. Tetrahedron: Asymmetry
26. A mixture of I2 (254 mg, 1 mmol) and Ag SO4 (170 mg, 1 mmol) in EtOH
2
(20 ml) was stirred until all the I2 had dissolved. Then 2 (185 mg, 0.5 mmol)
2
006, 17, 2401–2407; (d) Hu, Q. S.; Vitharana, D.; Zheng, X. F.; Wu, C.; Kwan, C.
was added and the mixture was stirred at room temperature for 12 h. After
filtration, EtOH was removed by distillation. The residue was dissolved in
CHCl3 (50 ml) and the solution was washed with saturated Na S O
M. S.; Pu, L. J. Org. Chem. 1996, 61, 8370–8377.
1
1
0. Shi, L.; Wang, X.; Sandoval, C. A.; Wang, Z.; Li, H.; Wu, J.; Yu, L.; Ding, K. Chem.
Eur. J. 2009, 15, 9855–9867.
1. (a) Ishitani, H.; Ueno, M.; Kobayashi, S. J. Am. Chem. Soc. 2000, 122, 8180–8186;
2
2 3
(3 ꢁ 50 ml). The organic layer was separated and dried over Na SO . After
2
4
evaporation of the solvent, the product was purified by column
chromatography (silica, toluene) and was obtained in 95% yield. Selected
(
b) Deussen, H. J.; Hendrickx, E.; Boutton, C.; Krog, D.; Clays, K.; Bechgaard, K.;
spectroscopic data for 4: 1H NMR (400 MHz, CDCl , d): 8.18 (d, J = 1.8 Hz, 1H);
Persoons, A.; Bjørnholm, T. J. Am. Chem. Soc. 1996, 118, 6841–6852.
3
1
1
2. (a) Balaraman, E.; Swamy, K. C. K. Tetrahedron: Asymmetry 2007, 18, 2037–
8.06 (d, J = 8.9 Hz, 1H); 7.96 (dd, J = 8.2 Hz, 1.2 Hz, 1H); 7.74 (d, J = 8.9 Hz, 1H);
7.50 (ddd, J = 8.2 Hz, 6.8 Hz, 1.2 Hz, 1H); 7.44 (dd, J = 8.9 Hz, 1.8 Hz, 1H); 7.35
(ddd, J = 8.3 Hz, 6.8 Hz, 1.2 Hz, 1H); 7.35 (d, J = 8.9 Hz, 1H); 7.29 (d, J = 8.9 Hz,
1H); 7.23 (dd, J = 8.3 Hz, 1.2 Hz, 1H); 6.77 (d, J = 8.9 Hz, 1H); 5.18 (br s, 1H);
2
2
048; (b) Yamashita, Y.; Ishitani, H.; Shimizu, H.; Kobayashi, S. J. Am. Chem. Soc.
002, 124, 3292–3302.
3. Zhang, S.; Liu, Y.; Huang, H.; Zheng, L.; Wu, L.; Cheng, Y. Synlett 2008,
53–856.
0.79 (s, 9H). 13C NMR (100.62 MHz, CDCl , d): 177.8; 152.3; 148.3; 136.5;
8
3
14. Regnouf de Vains, J. B. Tetrahedron Lett. 2001, 42, 6507–6509.
15. Cai, D.; Larsen, R. D.; Reider, P. J. Tetrahedron Lett. 2002, 43, 4055–4057.
16. Ma, L.; White, P. S.; Lin, W. J. Org. Chem. 2002, 67, 7577–7586.
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Kollár, L. J. Organomet. Chem. 2005, 690, 3237–3242.
135.0; 133.3; 132.5; 132.1; 131.0; 130.6; 129.2; 128.4; 127.6; 126.4; 126.3;
125.4; 122.2; 121.8; 119.2; 114.4; 88.5; 38.7; 26.5. MS (m/z (rel. int.)): 496
+
(M )(13); 412(39); 284(11); 255(21); 239(24); 226(38); 57(100).
27. Selected spectroscopic data for 5: 1H NMR (400 MHz, CDCl , d): 8.28 (d,
3
J = 1.7 Hz, 1H); 7.95 (d, J = 8.9 Hz, 1H); 7.89 (dd, J = 8.1 Hz, 1.2 Hz, 1H); 7.82 (d,
J = 8.9 Hz, 1H); 7.51 (dd, J = 8.9 Hz, 1.7 Hz, 1H); 7.44 (ddd, J = 8.1 Hz, 6.7 Hz,
1.2 Hz, 1H); 7.38 (d, J = 8.9 Hz, 1H); 7.35 (d, J = 8.9 Hz, 1H); 7.30 (ddd, J = 8.4 Hz,

3
2
632
C. Fehér et al. / Tetrahedron Letters 51 (2010) 3629–3632
.8 Hz, 1.2 Hz, 1H); 7.20 (dd, J = 8.4 Hz, 1.2 Hz, 1H); 7.01 (d, J = 8.9 Hz, 1H); 0.75 dried over Na SO . After evaporation of the solvent, the products 5 and 6 were
6
(
1
1
2
4
s, 9H); 0.72 (s, 9H). 1 C NMR (100.62 MHz, CDCl
3
, d): 176.3; 176.2; 147.4;
47.0; 136.5; 135.1; 133.2; 132.9; 132.3; 131.4; 129.5; 128.1; 127.9; 127.8;
26.8; 125.8; 125.6; 124.0; 123.0; 122.9; 121.8; 91.3; 38.6; 26.4; 26.3. MS (m/z
purified by column chromatography (silica, n-hexane/EtOAc = 3/1) and
3
obtained in 96% and 97% yields, respectively.
29. Selected spectroscopic data for 6: 1H NMR (400 MHz, CDCl
3
, d): 8.00 (br s, 1H);
+
(
rel. int.)): 580 (M )(10); 496(31); 412(83); 284(27); 255(38); 239(40);
26(54); 57(100).
8. 6-Iodo-2-hydroxy-2 -pivaloyloxy-1,1 -binaphthyl (4) or 6-bromo-2-hydroxy-
7.90 (d, J = 8.9 Hz, 1H); 7.84 (d, J = 8.2 Hz, 1H); 7.80 (d, J = 8.9 Hz, 1H); 7.39 (t,
J = 7.1 Hz, 1H); 7.50 (d, J = 8.9 Hz, 1H); 7.28–7.32 (m, 2H); 7.24 (t, J = 7.9 Hz,
2
0
0
1H); 7.16 (d, J = 8.9 Hz, 1H); 7.10 (d, J = 8.9 Hz, 1H); 0.70 (s, 9H); 0.67 (s, 9H).
0
0
13
2
-pivaloyloxy-1,1 -binaphthyl (3.5 mmol) and Et
3
N (7 mmol, 0.98 ml) were
3
C NMR (100.62 MHz, CDCl , d): 176.3; 176.2; 147.3; 147.0; 133.3; 132.5;
dissolved in MeCN (25 ml) under argon. The solution was cooled to 0 °C and
pivaloyl chloride (5.25 mmol, 0.65 ml) was added dropwise. The solution was
stirred for 1 h at 0 °C and then for 4 h at room temperature. The solvent was
132.0; 131.5; 130.0; 129.9; 129.5; 128.3; 128.0 (2C); 126.8; 125.8; 125.7;
124.1; 123.2; 123.0; 121.9; 119.8; 38.7; 26.4; 26.3. MS (m/z (rel. int.)): 532, 534
+
(M )(7); 448, 450(30); 364, 366(89); 284(35); 255(38); 239(42); 226(64);
removed in vacuo and the residue was dissolved in CHCl
3
(20 ml), washed with
57(100).
5
% HCl (2 ꢁ 20 ml), saturated NaHCO (20 ml), and brine (20 ml), and then
3