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ChemicalBook CAS DataBase List Pyridoxal hydrochloride
65-22-5

Pyridoxal hydrochloride synthesis

3synthesis methods
In the 25mL reaction flask with agitator and thermometer, add successively 0.085g (0.5mmol) 2,2,6,6-tetramethyl piperidine-nitrogen-oxyradical, 0.29g (2mmol) cupric bromide, 0.40g (5mmol) pyridine and 2.06g (10mmol) pyridoxinehydrochloride. Add water 5mL, temperature is controlled at 30 DEG C, opens and stirs.Then drip 2.0g (18mmol) 30% hydrogen peroxide, control temperature of reaction at 30～35 DEG C simultaneously.After dropwising, insulation continues to stir 1～2 hour at 30～35 DEG C, and gained reaction solution reaches 99% (liquid-phase condition: chromatographic column is XDB-G8 250 × 4.6 mm 5um through Liquid Detection pyridoxol transformation efficiency.Moving phase is methyl alcohol: buffer=15: 85; Buffer:0.04% sodium pentanesulfonate is adjusted PH to 3 with Glacial acetic acid; Detection wavelength is 284nm), reaction preference is 98%.
In addition, get about 5mL reaction solution and directly go up silicagel column, eluent is methylene dichloride: methyl alcohol=20: 1, obtain final elutriant through gradient elution, and be concentrated into dryly, can obtain white solidpyridoxalhydrochloride, fusing point 164.1-164.8 DEG C, nuclear-magnetism characterizes as follows: 1hNMR (400MHz, DMSO), δ: 8.27 (s, 1H, CHO), 6.63 (d, 1H, CH), 5.00-5.16 (m, 2H, CH2), 2.62 (s, 3H, CH3).
Because pyridoxalhydrochloride is unstable, difficult separation, reaction solution then adds p-ethoxyaniline 1.37g (10mmol), treated yellow Schiff alkali (IX) 2.10g that obtains without separating.The total recovery of two-step reaction is 88%.
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Yield:65-22-5 88 g

Reaction Conditions:

with hydrogenchloride;manganese(IV) oxide in water at 55; for 28 h;Temperature;

Steps:

2.1 Step 1. Preparation of pyridoxal hydrochloride

100 g of pyridoxine hydrochloride was dissolved in 1000 mL of 15% hydrochloric acid and 200 g of active was added.Manganese dioxide, stirred and heated to 55°C for reaction. After 28 hours of reaction, the raw material was completely converted and naturally cooled to room temperature 20-25.°C, the filtrate was filtered by vacuum filtration, and the filtrate was concentrated under reduced pressure at 60°C until no liquid flowed out to obtain a concentrate 1.Adding 400 mL of ethanol to the concentrate 1 and stirring it well, cooling down: Cool down to 5° C. within 10 hours to obtain a turbid liquid.The filter cake was dried to obtain 88 g of pyridoxal hydrochloride;

References:

CN107652323,2018,A Location in patent:Paragraph 0023; 0024

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