[Donphil07]

I synthesis chemical product from D-xylose, but I have problems in scheme 2, it is not pure product, it is all compound products. I don’t know why? I need the similar chemical magazine about protecting hydroxyl group by benzoyl chlorie.
Sceme 1, protect 1,2 diol in D-xylose by acetone, H2SO4,it was ok. Scheme 2: protect hydroxyl of C-5 by benzoyl chloride in pyridine, i am fail and i need a hand.