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expensive dicarboxylic acid derivatives. W e are now undergoing to make clear the scope and lim itations
of the reactions using various nucleophiles.
REFERENCES AND NOTES
1. For reviews and recent exam ples, see: (a) G. M. Dubowchick and M. A. Walker, Pharmacol. Ther.,
1999, 83, 67; (b) V. K. Rusiecki and S. A. W arne, Bioorg. Med. Chem. Lett., 1993, 3, 707; (c) K. D.
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3. M. C. Sheikh, S. Takagi, M. Sakai, A. H. Abe, and H. Morita, J. Org. Biomol. Chem., 2008, 6, 4505.
4. H. Morita,* M. C. Sheikh, S. Takagi, M. Ohira, M. Sakai, A. Narita, A. Ogasawara, T. Mori, and H.
Abe. Syntheses and R eactivities o f Non-Symm etrical "A ctive Es ter" Bi-dentate Cross-Link ing
Reagents having a Phthalim idoyl and Acid Chlo ride, 2-Benzothiazole, or 1-Benzotriazol Group," J.
Org. Biomol. Chem.,” submitted as a full paper.
5. A. R. Katrizky, X. Lan, J. Z. Yang, and O.V. Denisko, Chem. Rev., 1998, 98, 409.
6. 2-Benzyloxycarbonyl-1-[N-(benzyloxycarbonyl)]aniline (4). Typical procedure: A solution of DBU
(76.3 μL, 0.51 mmol) was added to a stirred solution of 2a (50.0 mg, 0.17 mmol) and benzyl alcohol
(52.8 μL, 0.51 mm ol) in CH Cl2 (2 m L) at rt under N 2 and stirred for 24 h. Then, the reaction
2
mixture was neutralized by dil. AcOH and extracted with C H2Cl2. The organic layer was separated,
successively washed with water and brine, and dried over anhydrous MgSO4. Removal of solvent in
vacuum ga ve a colorless oil crude product,
which was purified by preparative TLC (3:1
CH2Cl2/hexane) to give
4 (15.2 m g, 24%) as a colorless solid. Mp 74.0-74.5 °C (
from
1
CH2Cl2/hexane); H NMR (CDCl , 400 MHz) δ 5.21 (s, 2H), 5.33 (s, 2H), 6.98-7.02 (m
, 1H),
3
7.29-7.43 (m, 10H), 7.49-7.54 (m , 1H), 8.04 (dd, J = 2.0, 1.6 Hz, 1H), 8.46 (d, J = 8.4 Hz, 1H),
10.57 (s, 1H); 13C NMR (CDCl 3, 100 MHz) δ 66.9, 66.9, 114.5, 118.8, 121.6, 128.2, 128.2, 128.2,
128.4, 128.5, 128.6, 130.9, 134.7, 135.4, 136.1, 141.8, 153.4, 167.7; IR (KBr) 1738, 1685 cm-1. Anal.
Calcd for C22H19NO4: C, 73.12; H, 5.30; N, 3.88. Found: C, 73.37; H, 5.30; N, 3.97.
7. W. Lossen, Liebigs Ann. Chem., 1872, 175, 271.
8. (a) H. Ulric h, B. Tucer, and R. Ric hter, J. Org. Chem., 1978, 43, 1544. (b) T. L. Maillard, M.
Benohoud, P. Durand, and B. Badet, J. Org. Chem., 2005, 70, 6303.
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77, 765; (b) C. D. Hurd and L. Bauer, J. Am. Chem. Soc., 1954, 76, 2791.
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