Journal of Chemical Crystallography, Vol. 29, No. 11, 1999
Note
The crystallographic structure of a novel camphanic amide
Min Shi(1)* and Gui-Xin Lei(1)
Received September 10, 1999
The crystallographic structure of a novel camphanic amide 5 is disclosed by x-ray analysis.
It crystallized in the space group P212121(#19) with a ϭ 15.663(3), b ϭ 17.848(3), c ϭ 7.935(8)
3
3
˚
˚
A, V ϭ 2209.5(6) A , Dcalc ϭ 1.165 g/cm , and Z ϭ 4.
KEY WORDS: Chiral 1,3-diketones; samarium diiodide; (ϩ)-3Ͱ-bromocamphor.
Introduction
Chiral 1,3-diketones have wide applications in
Compound 3 was obtained from the reaction of
1 (0.50 g, 1.79 mmol) with thionyl chloride (1.0 mL
1.63 g, 13.7 mmol) under reflux for 2 h. After the
thionyl chloride was removed under reduced pres-
sure, compound 2 was obtained as a yellow solid
which was used for the next reaction without fur-
ther purification.
stereochemical research. For example, they can be
used as chiral ligands in asymmetric reactions,1 chiral
stationary phases on GC and HPLC for the determi-
nation of enantiomeric excess, and separation of en-
antiomers.2 Furthermore, their lanthanide complexes
can be used as optically active nuclear magnetic reso-
nance chemical shift reagents for the direct determi-
nation of enantiomeric compositions.3 Recently we
found a new synthetic method to prepare these im-
portant chiral compounds from (ϩ)-3Ͱ-bromo-
camphor 1 with various acyl chlorides in the presence
of samarium diiodide (SmI2) under mild reaction con-
ditions (Scheme 1).4
However, in the reaction of 1 with acetyl chlo-
ride, in addition to the desired chiral 1, 3-diketone
4, the O-acetyl derivative 5 was also obtained as a
by product in 10% yield. Herein, we wish to report the
X-ray crystallographic structure of this novel chiral
compound 5.
To a solution of 2 in dichloromethane was added
dicyclohexylamine (0.53 g, 0.58 mL, 2.92 mmol) and
triethylamine (0.3 g, 0.41 mL, 2.92 mmol) and the
reaction mixture was stirred at 0ЊC for 1 h, then at
room temperature for 12 h. The solution was washed
with 20 mL water 3% HCl aqueous solution and ex-
tracted with dichloromethane (10 mL ϫ 3). The or-
ganic layer was dried over anhydrous MgSO4. The
solvent was removed under reduced pressure and the
residue was purified by silica gel column chromatog-
raphy to give compound 3 as a colorless solid (0.38
g, 31%). m.p. 144–146ЊC; [Ͱ]Dϩ82.1 (c 0.40, CHCl3);
IR (KBr) 1720 cmϪ1 (CuO); ͳH (CDCl3) 1.28 (3H,
s, Me), 1.34 (3H, s, Me), 0.85–2.36 (23H, m), 2.40-
2.60 (2H, m), 2.80–3.0 (1H, m), 3.30–3.40 (1H, m),
4.63 (1H, d, J 5.2 Hz); MS (El) m/z 425 (Mϩ); Found:
C, 62.46; H, 8.32; N, 3.43%. Calc. for C22H34BrNO2
(424.4149) requires C, 62.26; H, 8.07; N, 3.30%.
Compound 5 was obtained by the reaction of
(ϩ)Ϫ3Ͱ-bromocamphor 3 (424 mg, 1.0 mmol) with
acetyl chloride (78 mg, 1.0 mmol) in anhydrous THF
(30 mL) in the presence of SmI2 (2 mmol) which
was prepared from Sm and CH2I2 and the reaction
mixture was stirred for 10 h at 0ЊC. The solvent was
removed under reduced pressure and 10 mL 5% HCl
Experimental
Compound 1 was obtained according to the
literature.5
(1) Laboratory of Organometallic Chemistry, Shanghai Institute of
Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin
Lu, Shanghai 200032 China.
* To whom correspondence should be addressed.
1211
1074-1542/99/1100-1211$16.00/0 1999 Plenum Publishing Corporation
Shi, Min
