Yield:-

Reaction Conditions:

Stage #1: riboflavinwith pyridine;water;trichlorophosphate in acetonitrile at 15; for 16 h;
Stage #2: with hydrogenchloride in water at 50; for 6 h;
Stage #3: with sodium hydroxide in water at 40; pH=9; for 12 h;

Steps:

Example:

1, acetonitrile, pyridine, phosphorus oxychloride, riboflavin into the reactor, then add water (1h), at 15 for 16h.2, filter, filter with a metal rod microporous filter 3h, the filtrate hit the hydrolysis tank.3, hydrolysis, in the hydrolysis tank add hydrochloric acid (9%) acidification, reaction at 50 6h,Sodium hydroxide (25%) was added to adjust the pH to about 9 and cooled to 40 ° C for 12 h.4, filter, filter with metal rods microporous filter 3h, the filter cake to the crystallization tank.5, crystallization,An excess of sodium hydroxide was neutralized by addition of hydrochloric acid (30%) to the crystallization vessel,The pH was adjusted to 5.5 and allowed to cool to 5 ° C. Maintain 10h.6, filter, filter 1.5 hours with a centrifuge, the wet cake into the beating cans, beating with ethanol water, stirring for one hour,And then filtered 1.5h.7. Dry, dry at 50 ° C with a double cone dryer for 12 h, until the product is less than 10% moisture.

References:

CN105273008,2016,A Location in patent:Paragraph 0015; 0016; 0017; 0018; 0019; 0020; 0021; 0022