Baicalin and 8-methylamine derivatives of baicalin and its esters and preparation method thereof

[0035] Example 1: Preparation of 8-(N,N-diethyl-aminomethyl)-baicalin;

[0036] Take 5g of baicalin with a content of 85%, add 20ml of glacial acetic acid, add 5ml of formaldehyde with a mass concentration of 40%, add 3ml of diethylamine with a mass concentration of 99%, and react in a water bath at 90℃ until the baicalin is dissolved, then continue the reaction 1h, filter, take the filtrate, recover the solvent under reduced pressure at 70°C, add 100ml of distilled water, warm at 60°C for 10min, filter while hot, and wash the filtrate with 50g of macroporous resin, 100ml of distilled water, and 200ml of ethanol with a mass concentration of 80%. The ethanol is recovered to obtain 4.1 g of 8-(N,N-diethyl-aminomethyl)-baicalin, which is determined by HPLC and its content is 88.6%. MS(ESI) m / z: 532.4060 [M+H] + ; 13 CNMR (100MHz, DMSO-d6): 162.41 (C2), 104.82 (C3), 181.43 (C4), 146.69 (C5), 130.82 (C6), 150.18 (C7), 106.72 (C8), 148.05 (C9), 104.31 (C10), 51.44 (C11), 51.58 (C12, C1

[0039] Example 2: 8-(N,N-Dimethyl-aminomethyl)-baicalin;

[0040] Take 10g of baicalin with a content of 85%, add 60ml of glacial acetic acid, add 10ml of formaldehyde with a mass concentration of 40%, add 7ml of dimethylamine with a mass concentration of 40%, react in a water bath at 90°C for 8h, filter, and take the filtrate at 70°C Recover the solvent under reduced pressure, add 100ml of distilled water, heat to dissolve, filter while hot, let the filtrate cool, place for crystallization, filter with suction, take the filter residue and dry at 40°C to obtain 8-(N,N-dimethyl-aminomethyl) )-Baicalin 6.8g, determined by HPLC, its content is 87.4%. MS(ESI) m / z: 504.2567[M+H] + ; 13 CNMR (100MHz, DMSO-d6): 162.44 (C2), 104.83 (C3), 181.45 (C4), 146.71 (C5), 130.84 (C6), 150.20 (C7), 106.73 (C8), 148.07 (C9), 104.33 (C10), 51.48 (C11), 42.43 (C12, C13), 130.83 (C1'), 129.60 (C2', C4'), 127.91 (C3', C5'), 130.43 (C4'), 100.21 (C1') '), 72.91 (C2''), 75.65 (C3''), 71.53 (C4''), 75.41

[0043] Example 3: 8-(N,N-diethyl-aminomethyl)-baicalin;

[0044] Take 5g of baicalin with a content of 85%, add 20ml of DMSO, add 5ml of formaldehyde with a mass concentration of 40%, add 3ml of diethylamine with a mass concentration of 99%, react in a water bath at 90℃ for 10h, filter, and add 100ml of distilled water to the filtrate, 60 Warm it at ℃ for 30 minutes, filter while it is hot, and wash the filtrate with 50g of macroporous adsorption resin, wash with 100ml of distilled water, wash with 200ml of ethanol with a mass concentration of 80%, and recover the ethanol to obtain 8-(N,N-diethyl-aminomethyl) )-Baicalin 4.3g, determined by HPLC, its content is 88.1%. The structural formula is the same as before.