A kind of synthesis method of (rs)-2-(10-hydrogen-9-oxa-1-azanthracen-6-yl) propionic acid degradation impurity
A technology of ethyl and nicotinic acid, which is applied in the direction of organic chemistry, can solve the problems of cumbersome synthesis process and difficulty in obtaining it, and achieve the effects of high yield, stable quality and mild reaction conditions
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Embodiment 1
[0032] 1. Preparation of 2-(4-ethylphenoxy)nicotinic acid
[0033] In a dry 100mL round-bottomed flask, add 30mL of anhydrous methanol and 6.1g of sodium methoxide, add 24g of p-ethylphenol under stirring at room temperature, continue stirring for 5min after addition, then add 8.8g of 2-chloronicotinic acid, and reflux reaction 1h; distill methanol off, raise the temperature to 180-190°C to continue the reaction for 1h, stop heating, and when the temperature of the reaction solution drops to 100°C, pour it into 60mL of ice water, extract with ethyl acetate, and wash the water layer with concentrated hydrochloric acid (37wt %, the same as in the following examples) Adjust the pH value to 2, a large amount of white solid precipitated out, filtered with suction, washed the filter cake with a small amount of water, and dried to obtain 8.2 g of white solid, with a yield of 60%. 1 H-NMR(d-DMSO,400MHz)δ(ppm):1.19(m,3H);2.1(m,2H);6.99(d,2H,J=8.4Hz);7.21(m,3H);8.24( m,2H); 13.21(s,1H)...
Embodiment 2
[0037] 1. Preparation of 2-(4-ethylphenoxy)nicotinic acid
[0038] In a 100mL round bottom flask, add 30mL of methanol and 4.5g of sodium hydroxide, add 24g of p-ethylphenol under stirring at room temperature, continue stirring for 5min after addition, then add 8.8g of 2-chloronicotinic acid, and reflux for 1h; Remove methanol, raise the temperature to 180-190°C to continue the reaction for 1 hour, stop heating, and when the temperature of the reaction solution drops to 100°C, pour it into 60mL of ice water, extract with ethyl acetate, and adjust the pH value of the water layer to 2 with concentrated hydrochloric acid. , a large amount of white solid was precipitated, suction filtered, the filter cake was washed with a small amount of water, and dried to obtain 7.1 g of white solid, with a yield of 52%, and its structural formula was confirmed by H NMR spectrum.
[0039] 2. Preparation of 7-ethyl-5-oxo-5H-[1]benzopyrano[2,3-b]pyridine
[0040] In a dry 250mL round bottom flas...
Embodiment 3
[0042] 1. Preparation of 2-(4-ethylphenoxy)nicotinic acid
[0043] In a dry 1L round-bottomed flask, add 300mL of anhydrous methanol and 60g of sodium methoxide, add 240g of p-ethylphenol under stirring at room temperature, continue stirring for 5min after addition, then add 90g of 2-chloronicotinic acid, and reflux for 1h. Distill methanol off, raise the temperature to 180-190°C and continue the reaction for 1 hour, stop heating, and when the temperature of the reaction solution drops to 100°C, pour it into 600mL of ice water, extract with ethyl acetate, and adjust the pH value of the water layer with concentrated hydrochloric acid to 2. A large amount of white solid was precipitated, filtered with suction, the filter cake was washed with a small amount of water, and dried to obtain 87 g of white solid, with a yield of 64%. Its structural formula was confirmed by H NMR spectrum.
[0044] 2. Preparation of 7-ethyl-5-oxo-5H-[1]benzopyrano[2,3-b]pyridine
[0045] In a dry 3L ro...
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