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With N,N,N',N'-tetramethylguanidine In neat liquid at 20℃; for 0.583333 h;
General procedure: TMG (3.5 mmol) was added to a mixture of SA (1 mmol), MN (1 mmol) and DAP (1 mmol) in neat condition. The resulting mixture was stirred at room temperature. After completion of the reaction (monitored by TLC), distilled water (15 mL) was added to the reaction mixture and stirring continued till a free flowing solid was obtained. It was filtered and then washed successively with water, n-hexane. The crude product was purified by recrystallization from ethanol solution. For this, the crude product was saturated in boiling ethanol and then the solution mixture was filtered when it was hot to remove the undissolved solid. The hot filtrate cooled down to room temperature to afford elemental analytically pure crystalline product. The similar experimental procedures were adopted for the synthesis of all the 2-amino-4H-chrormens.
55%
at 20℃; Molecular sieve
Ethyl-2-amino-6-bromo-4-(1-cyano-2-ethoxy-2-oxoethyl)-4H-chromene-3-carboxylate (HA14-1) was purchased from Wako (Tokyo, Japan) or prepared by following an established procedure [12]. In short, 5-bromosalicylaldehyde was treated with ethyl cyanoacetate in the presence of MS3A in dry ethanol at room temperature to produce HA14-1 with a 55percent yield. Synthesized HA14-1 had inhibitory activity comparable with commercial HA14-1.
Reference:
[1] Tetrahedron Letters, 2005, vol. 46, # 20, p. 3497 - 3499
[2] RSC Advances, 2015, vol. 5, # 80, p. 65526 - 65531
[3] Tetrahedron, 2013, vol. 69, # 49, p. 10544 - 10551
[4] Tetrahedron Letters, 2006, vol. 47, # 43, p. 7629 - 7633
[5] Russian Chemical Bulletin, 2008, vol. 57, # 3, p. 595 - 600
[6] Tetrahedron Letters, 2000, vol. 41, # 36, p. 6993 - 6996
[7] Tetrahedron Letters, 2008, vol. 49, # 20, p. 3276 - 3278
[8] Biochemical and Biophysical Research Communications, 2013, vol. 433, # 2, p. 170 - 174
With N,N,N',N'-tetramethylguanidine; In neat liquid; at 20℃; for 0.583333h;
General procedure: TMG (3.5 mmol) was added to a mixture of SA (1 mmol), MN (1 mmol) and DAP (1 mmol) in neat condition. The resulting mixture was stirred at room temperature. After completion of the reaction (monitored by TLC), distilled water (15 mL) was added to the reaction mixture and stirring continued till a free flowing solid was obtained. It was filtered and then washed successively with water, n-hexane. The crude product was purified by recrystallization from ethanol solution. For this, the crude product was saturated in boiling ethanol and then the solution mixture was filtered when it was hot to remove the undissolved solid. The hot filtrate cooled down to room temperature to afford elemental analytically pure crystalline product. The similar experimental procedures were adopted for the synthesis of all the 2-amino-4H-chrormens.
55%
In ethanol; at 20℃;Molecular sieve;
Ethyl-2-amino-6-bromo-4-(1-cyano-2-ethoxy-2-oxoethyl)-4H-chromene-3-carboxylate (HA14-1) was purchased from Wako (Tokyo, Japan) or prepared by following an established procedure [12]. In short, 5-bromosalicylaldehyde was treated with ethyl cyanoacetate in the presence of MS3A in dry ethanol at room temperature to produce HA14-1 with a 55percent yield. Synthesized HA14-1 had inhibitory activity comparable with commercial HA14-1.