K. Kinbara et al. / Tetrahedron 56 (2000) 6651±6655
6655
pressure, the crude acid was obtained as a white solid
(1.20 g), which was puri®ed by recrystallization from etha-
nol/chloroform (0.9/10 mL) to afford pure (S)-2 (0.74 g,
55% yield). Enantiomeric excess of (S)-2 was determined
by an HPLC analysis on Daicel Chiralcel OD (eluent: hex-
ane/2-propanol19/1), after (S)-2 was converted into the
corresponding methyl ester with diazomethane. (S)-2: mp
129.5±131.08C (lit.5 129±1318C for (R)-2); IR (KBr)
Scienti®c Research (Nos. 09450330 and 10750618) from
the Ministry of Education, Science, Sports and Culture of
Japan, and the Kawakami Memorial Foundation.
References
n3440, 3250±2460, 1725, 1505, 1120, 810 cm21
;
1H
1. Jacques, J.; Collet, A.; Wilen, S. H. Enantiomers, Racemates,
and Resolutions, Krieger: Malabar, Florida, 1994.
2. (a) Kinbara, K.; Sakai, K.; Hashimoto Y.; Nohira, H.; Saigo, K.
Tetrahedron: Asymmetry 1996, 7, 1539. (b) Kinbara, K.; Sakai, K.;
Hashimoto, Y.; Nohira, H.; Saigo, K. J. Chem. Soc., Perkin Trans.
2 1996, 2615.
NMR (300 MHz, [D6] DMSO/CDCl3): d5.04 (s, 1H),
5.95 (s, 2H), 6.76 (d, J8.4 Hz, 1H), and 6.95 (m, 2H);
[a]1D81120.5 (c1.0 in EtOH) (lit.5 [a]2128.5 (in
EtOH) for (R)-2).
Optical resolution of racemic amines with (S)-2
3. (a) Kinbara, K.; Harada, Y.; Saigo, K. Tetrahedron: Asymmetry
1998, 9, 2219. (b) Kinbara, K.; Harada, Y.; Saigo, K. J. Chem. Soc.,
Perkin Trans 2, 2000, 1339.
To a solution of a racemic amine in aqueous ethanol (the
amount and ratio are listed in Table 1) was added an equi-
molar amount of (S)-2, and the mixture was heated to re¯ux.
The solution was then slowly cooled to 308C and left stand-
ing for 12 h in a water bath kept at 308C. The precipitated
crystalline salt was collected by ®ltration. The salt was
dissolved in water, and basi®ed to pH10 with potassium
hydroxide. The liberated oil was extracted with dichloro-
methane for a few times, and the combined organic extracts
were dried over anhydrous magnesium sulfate. Upon
removal of the solvent under reduced pressure, the amine
was obtained as a colorless oil, of which the enantiomeric
excess was determined by HPLC on Daicel CrownPak
CR(1).
4. Compere Jr., L. E. J. Org. Chem. 1968, 33, 2565.
5. Neilson, D. G.; Zakir, U.; Scrimgeour, C. M. J. Chem. Soc., C
1971, 898.
6. (a) Saigo, K.; Ozawa, S.; Kikuchi, S.; Kasahara, A.; Nohira, H.
Bull. Chem. Soc. Jpn 1982, 55, 1568. (b) Saigo, K.; Sugiura, I.;
Shida, I.; Tachibana, K.; Hasegawa, M. Bull. Chem. Soc. Jpn 1986,
59, 2915. (c) Kinbara, K.; Kobayashi, Y.; Saigo, K. J. Chem. Soc.,
Perkin Trans. 2 1998, 1767.
7. Crystallographic data: (S)-2´(S)-4g: orthorhombic, P212121,
Ê
Ê 3
a8.453(2), b27.926(9), c7.005(2) A, V1653.7(8) A , Z4,
r1.413 g cm21, m2.299 cm21, 1560 unique re¯ections, 1486
observed, R0.079, Rw0.102. (S)-2´(R)-4g: monoclinic, P21,
Ê
a15.586(4), b6.048(2), c9.148(2) A, b97.26 (2)8,
Ê 3
V855.3(4) A , Z2, r1.366 g cm21, m2.222 cm21, 1541
Crystal-structure determination and re®nement
unique re¯ections, 1479 observed, R0.086, Rw0.117.
8. The melting points of (S)-2´(S)-4g and (S)-2´(R)-4g were 198.0±
204.58C and 167.0±170.58C, respectively. These results suggests
that less-soluble (S)-2´(S)-4g is thermodynamically more stable
than the corresponding more-soluble (S)-2´(R)-4g. However, we
could not detect a clear evidence in the IR spectra that the
hydrogen-bonding interaction is stronger in (S)-2´(S)-4g than in
(S)-2´(R)-4g.
The X-ray intensities were measured up to 2u1308 with
Ê
graphite-monochromated CuKa radiation (l1.5418 A) on
a Mac Science MXC18 four-circle diffractometer by a
2u2v scan. All of the data were collected at 293 K. The
cell dimensions were obtained by least-square analyses of
the setting angles of 20 re¯ections (508,2u,608). The
intensities and orientation of the crystals were checked by
three standard re¯ections every 100 re¯ections.
9. Nishio, M.; Hirota, M.; Umezawa, Y. CH´´´p Interaction:
Evidence, Nature, and Consequences, Wiley-VCH: Weinheim,
Berlin, 1998.
The structures were solved and re®ned by applying the
crystan-gm package;13 the direct method (SIR9214)
followed by normal heavy-atom procedures, and full-matrix
least-squares re®nement with all non-hydrogen atoms aniso-
tropic and hydrogens in calculated positions with thermal
parameters equal to those of the atom to which they were
bonded. Atomic coordinates, thermal parameters, bond
lengths and angles for all diastereomeric salts have been
deposited at the Cambridge Crystallographic Data Centre.
10. The calculations were performed at B3LYP/6-3111G(d,p)
level using gaussian 9411 program.
11. Frisch, M. J; Trucks, G. W.; Schlegel, H. B.; Gill, P. M. W.;
Johnson, B. G.; Robb, M. A.; Cheeseman, J. R.; Keith, T.;
Petersson, G. A.; Montgomery, J. A.; Raghavachari, K.; Al-Laham,
M. A.; Zakrzewski, V. G.; Ortiz, J. V.; Foresman, J. B.;
Cioslowski, J.; Stefanov, B. B.; Nanayakkara, A.; Challacombe,
M.; Peng, C. Y.; Ayala, P. Y.; Chen, W.; Wong, M. W.; Andres,
J. L.; Replogle, E. S.; Gomperts, R.; Martin, R. L.; Fox, D. J.;
Binkley, J. S.; Defrees, D. J.; Baker, J.; Stewart, J. P.; Head-
Gordon, M.; Gonzalez, C.; Pople, J. A. gaussian 94, Revision
D.3; Gaussian: Pittsburgh, PA, 1995.
(S)-2´(S)-4g. Mp 203.0±209.58C; nmax/cm21 3200±2400,
1570, 1530, 1500, 1485, 930 and 810.
12. Borch, R. F.; Bernstein, M. D.; Drust, H. D. J. Am. Chem. Soc.
1971, 93, 2897.
(S)-2´(R)-4g. Mp 177.0±181.58C; nmax/cm21 3200±2400,
1560, 1540, 1495, 930 and 820.
13. crystan gm, A Computer Program for the Solution and
Re®nement of Crystal Structures for X-ray Diffraction Data
(MAC Science Corporation).
Acknowledgements
14. Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A.
J. Appl. Crystallogr. 1993, 26, 343.
The present work was supported by Grants-in-Aid for