Benzyl 2-(1-cyanoethylamino)acetate (3i)24. The compound
was prepared according to method B, using HCl¥HGlyOBn
(2.0 mmol, 0.402 g), diisopropylamine (2.3 mmol, 400 mL),
acetaldehyde 2a (2.5 mmol, 140 mL), trimethylsilyl cyanide
(2.2 mmol, 280 mL) and a temperature of 100 ◦C. Purification
by flash chromatography, eluent ethyl acetate:iso-hexane 30:70 to
75:25. Colorless oil, 68% yield. 13C-NMR (CD3OD) d 172.5, 137.3,
129.7, 129.5 (two peaks), 121.7, 67.8, 49.2, 45.8, 19.6.
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13 E. Suna and I. Mutule, Top. Curr. Chem., 2006, 266, 49–101.
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L. Mamedova, P. H. Vu, K. S. S. Lee, N. K. Minami, T. S. Gibson,
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Benzyl 2-(3,5-dichloro-6-methyl-2-oxopyrazin-1(2H)-yl)acetate
(4q)24. The compound was prepared according to method C. Pu-
rification by flash chromatography, eluent ethyl acetate:iso-hexane
20:80 to 35:65. Pale yellow solid, 86% yield. 13C-NMR (CDCl3) d
166.1, 152.7, 143.8, 135.2, 134.6, 129.1, 129.0, 128.7, 124.0, 68.4,
47.6, 16.9. ESI-MS (m/z) 327 (M + H+), 655 (2M + H+).
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19 A 2.0 mL microwave vial was loaded with 2(1H)-pyrazinones 4j–
n (0.05–0.15 mmol), (1S,2R)-cis-1-amino-2-indanol (3 equiv.) and
acetonitrile (2.0 mL). The reactions were then irradiated by microwaves:
4j at 150 ◦C for 1.5 h; 4k at 140 ◦C for 2 h; 4l at 140 ◦C for 0.5 h; 4m
at 160 ◦C for 2 h; 4n at 160 ◦C for 1.5 h. The diastereomeric ratios
were determined by 1H-NMR or by HPLC separation with ELSD and
ESI-MS detection.
Acknowledgements
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We gratefully acknowledge the financial support from the Foun-
dation for Strategic Research, the Swedish Research Council
and Knut and Alice Wallenberg’s Foundation. We also thank
Prof. Helena Danielson and Angelica Ehrenberg for biochemical
evaluation of compound 7, Mr Gunnar Wikman for critical review
of this paper and Dr. Luke Odell for linguistic advice.
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