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F.; Gleason, J. G. J. Am. Chem. Soc. 1977, 99, 2353–2355;
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antyl esters, as well as N-Boc-amines and amino acids
derivatives, without affecting additional functions pres-
ent in the substrates. The proposed method represents
a useful simple, cheap, eco-friendly and safe protocol,
which is a valid alternative to existing ones, being espe-
cially suitable in large scale applications.
Spiegler, C.; Muller, K. Helv. Chim. Acta 1995, 78, 563–
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580; (d) Pandey, G.; Bagul, T. D.; Sahoo, A. K. J. Org.
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Acknowledgements
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7866.
We are indebted to Professor G. Verardo for MS data
collection and to Dr. P. Martinuzzi for recording the
NMR spectra. Thanks are due to the University of
Udine (F. U. R. D.) for financial support.
12. (a) Strazzolini, P.; DallÕArche, M. G.; Giumanini, A. G.
Tetrahedron Lett. 1998, 39, 9255–9258; (b) Strazzolini, P.;
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13. Strazzolini, P.; Melloni, T.; Giumanini, A. G. Tetrahedron
2001, 57, 9033–9043.
14. Comely, A. C.; Gibson, S. E.; Hales, N. J.; Peplow, M. A.
J. Chem. Soc., Perkin Trans. 1 2001, 2526–2531, Prepared
in 88% yield, according to Ref. 12b, method B.
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References and notes
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16. Prepared according to Ref. 13. (3,5-dimethylphenyl)car-
bamic acid 1,1-dimethylethyl ester (3f). White solid (92%
yield): mp (from pentane) 93 ꢁC. IR (pellet) mmax: 3360s,
br; 2969m, br; 1696s; 1612m; 1523s; 1434m; 1365w;
1279m; 1236m; 1162s; 1078w; 1011w; 1021w; 979w;
`
Lett. 1994, 209–212; (h) Stanton, M. G.; Gagne, M. R. J.
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dron Lett. 1997, 38, 7345–7348.
1
847m; 761w; 688w; 618w cmÀ1. H NMR d (ppm): 6.99
(app br s, 2 H, Ar–H); 6.71–6.64 (m, 1 H, Ar–H); 6.44 (br
s, 1 H, BocNH); 2.28–2.25(m, 6 H, ArC H3); 1.51 [s, 9 H,
OC(CH3)3]. 13C NMR d (ppm): 152.78; 138.58; 138.13;
2. (a) Wunsch, E.; et al. In Methoden Der Organischen
Chemie, Houben-Weyl; Muller, E., Ed.; G. Thieme:
¨
Stuttgart (D), 1974; Vol. XV/1 (Synthese von Peptiden
I), pp 390–398; (b) Bodanszky, M. In Principles of Peptide
Synthesis; Hafner, K. et al., Ed.; Springer: Heidelberg (D),
1984; Vol. 16, p 78.
124.70; 116.20; 80.24; 28.30; 21.31. MS (T = 20 ꢁC) m/z:
+
121 (100); 165(93); 57 (22); 41 (21); 120 (16); 221 (M
,
<1). Anal. Calcd for C13H19NO2: C, 70.56; H, 8.65; N,
6.33. Found: C, 70.41; H, 8.69; N, 6.31.
3. Ref. 2b, pp 120–122 and 128–130.
4. Okada, Y.; Iguchi, S. J. Chem. Soc., Perkin Trans. 1 1988,
2129–2136.
17. Hagiwara, D.; Miyake, H.; Morimoto, H.; Murai, M.;
Fujii, T.; Matsuo, M. J. Med. Chem. 1992, 35, 3184–3191,
Prepared in 76% yield by treating a chilled CH2Cl2
(50 mL) solution of commercial N-Boc-L-phenylalanine
(10.0 mmol) and (phenylmethyl)amine (10.0 mmol), with a
CH2Cl2 (20 mL) solution of dicyclohexylcarbodiimide
(DCC, 10.0 mmol), and stirring 24 h at rt. The reaction
mixture was then filtered in order to separate formed
DCU, concentrated to dryness, the residue redissolved in
EtOAc (60 mL) and washed with 0.1 M HCl (50 mL), 10%
aqueous Na2CO3 (50 mL) and 10% aqueous Na2SO4
(50 mL). The organic phase was finally dried over anhy-
drous Na2SO4, filtered, concentrated to dryness and the
residue crystallized from hexane.
5. (a) Ref. 1a, pp 192–195; (b) Ref. 1b, pp 518–525.
6. (a) Carpino, L. A.; Parameswaran, K. N.; Kirkley, R. K.;
Spiewak, J. W.; Schmitz, E. J. Org. Chem. 1970, 35, 3291–
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Chem. Res. (S) 1988, 346–347; (c) Almeida, M. L. S.;
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1988, 1905–1911; (d) Ragnarsson, U.; Grehn, L. Acc.
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Lipton, M. A. J. Org. Chem. 1997, 62, 1540–1542; (g)
Shapiro, G.; Marzi, M. J. Org. Chem. 1997, 62, 7096–
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7726–7735; (i) Burkhart, F.; Hoffmann, M.; Kessler, H.
Angew. Chem., Int. Ed. Engl. 1997, 36, 1191–1192; (j)
Bonini, B. F.; Comes-Franchini, M.; Fochi, M.; Mazzanti,
G.; Ricci, A.; Varchi, G. Synlett 1998, 1013–1015; (k)
Johnson, C. N.; Stemp, G.; Anand, N.; Stephen, S. C.;
Gallagher, T. Synlett 1998, 1025–1027.
18. Adrian, F.; Burguete, M. I.; Fraile, J. M.; Garcia, J. I.;
Garcia, J.; Garcia-Espan˜a, E.; Luis, S. V.; Mayoral, J. A.;
Royo, A. J.; Sanchez, M. C. Eur. J. Inorg. Chem. 1999,
2347–2354.
19. Prepared essentially as 3h. [(1S)-2-oxo-1-[(phenylmeth-
oxy)methyl]-2-[(phenylmethyl)amino]ethylcarbamic acid
1,1-dimethylethyl ester (3i). White solid (54% yield): mp
20
(from hexane) 79 ꢁC; ½aꢀD +50.0 (c 1.0; CHCl3). IR (pellet)
7. (a) Ref. 2a, pp 117–132; (b) Ref. 2b, pp 90–102; (c) Kaiser,
E. Sr.; Picart, F.; Kubiak, T.; Tam, J. P.; Merrifield, R. B.
J. Org. Chem. 1993, 58, 5167–5175.
mmax: 3334s, br; 2930m, br; 1686s; 1659s; 1529s; 1456w;
1368w; 1304m; 1241m; 1170m; 1109w; 1021w; 873w;
739w; 697m cmÀ1 1H NMR d (ppm): 7.36–7.17 (m,
.
8. Giordano, C.; Gallina, C.; Ottaviano, V.; Consalvi, V.;
Scandurra, S. Eur. J. Med. Chem. 1992, 27, 865–
873.
10H, Ar–H); 6.87 (t, J = 5.5 Hz, 1H, BnNH); 5.48 (d,
JMX = 6.3 Hz, 1H, BocNH); 4.53 (d, JAB = 11.7 Hz, 1H,
PhCH2O); 4.47 (d, JAB = 11.7 Hz, 1H, PhCH2O); 4.44 (d,