Molecules 2002, 7
74
Caution: Although we have not experienced any accidents while using LiClO , the authors advise that
4
this reagent should always be dried in a hood equipped with a suitable lab-shield.
General Procedure for the Preparation of Primary Aminoesters 8:
Hexamethyldisilazane (3.5 mmol, 0.24 mL) was placed under argon in two-necked flask fitted with
a condenser and a stirring bar. Diethyl ether (3 mL) and 3.7 mmol of sodium hydride (60-65%, after
washing with light pet. ether) were added, and the mixture was stirred for about 30 min. Then 3 mL of
a 5M solution of lithium perchlorate in diethyl ether and 2 mmol of aldehyde were added via syringe.
After stirring for 30 min., the bromoalkylzinc ester, BrZnCH COOEt, (3.5 mmol) was added, and the
2
mixture was stirred for an additional 2.0 hours. Water (10 mL) was then added and the product was
extracted with dichloromethane (2x10 mL). The organic layer was separated and extracted with cold
0.5 M HCl solution. Neutralization with 2.0 M KOH solution gave the desired products. Further
purification was done by preparative gas chromatography if needed. All products described had
structures in accordance with their spectroscopic data.
Spectroscopic data
-1 1
8
a, oil, (65%), IR (neat), νmax 3538 (NH ), 1730 (C=O) cm ; H-NMR (CDCl ): δ 1.20 (t, 3H, J 7.2
2 3
OCH CH ), 2.00 (br. s, 2H, NH ), 2.60 (d, 2H, J 6.7 CH CH), 4.10 (q, J 7.2, 2H, OCH CH ), 5.10 (t, J
2
3
2
2
2
3
6
.7, 1H, CH CH), 7.20 (s, 5H, Ar-H) [4].
2
-1 1
8
b, oil, (78%), IR (neat), νmax 3400 (NH ), 1725 (C=O) cm ; H-NMR (CDCl ): δ 1.20 (t, 3H, J 7.1
2 3
OCH CH ), 2.20 (br. s, 2H, NH ), 2.60 (d, 2H, J 6.7 CH CH), 4.10 (q, J 7.1, 2H, OCH CH ), 4.40 (t, J
2
3
2
2
2
3
6
.7, 1H, CH CH), 7.10-7.30 (m, 1H, Ar-H), 7.60-7.80 (m, 1H, Ar-H), 8.40-8.60 (m, 2H, Ar-H).
2
-1 1
8
c, oil, (60%), IR (neat), νmax 3389 (NH ), 1723 (C=O) cm ; H-NMR (CDCl ): δ 1.10 (t, 3H, J 7.4
2 3
OCH CH ), 2.00 (br. s, 2H, NH ), 2.70 (d, 2H, J 5.7 CH CH), 3.40 (m, 1H, CH CH), 4.10 (q, J 7.4,
2
3
2
2
2
2
H, OCH CH ), 6.20-6.60 (m, 2H, CH=CH), 7.10-7.45 (5H, Ar).
2 3
References
1. Saidi, M. R.; Khalaji, H. R.; Ipaktschi, J. J. Chem. Soc., Perkin Trans. 1, 1997, 1983-1986.
2. Saidi, M. R.; Azizi, N.; Zali-Boinee, H. Tetrahedron, 2001, 57, 6829-6832.
3. Ochiai, H.; Nishihara, T.; Tamaru, Y.; Yoshida, Z. J. Org. Chem., 1988, 53, 1343-1345.
4. Cole, D. Tetrahedron, 1994, 50, 9517-9582.
Sample availability: available from the authors.
2002 by MDPI (http://www.mdpi.org). Reproduction is permitted for noncommercial purposes
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