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US 7,402,713 B2Granted
Processes for conversion of tyrosine to p-hydroxystyrene and p-acetoxystyrene
AssigneeE.I. du Pont de Nemours and Company
InventorsSteven W. Shuey, Mukesh C. Shah
Life of this patent
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Abstract
Tyrosine was converted to p-hydroxystyrene in a two-step reaction without purification of individual intermediates. Conditions were determined for bromination of tyrosine in which reactive intermediates were formed. The mixture of these intermediates was used directly in a second step reaction to produce p-hydroxystyrene. The p-hydroxystyrene was further acetylated to produce p-acetoxystyrene in the second step reaction vessel.
Claims23
A method for the synthesis of p-hydroxystyrene comprising:
- a) reacting tyrosine in the presence of HBr and NaNO2 to form an isomeric bromide product mixture of 2-bromo-(3-p-hydroxyphenyl) propionic acid and 3-bromo-(2-p-hydroxyphenyl) propionic acid, according to Formula I:
- Formula I:
- b) isolating the isomeric bromide product mixture of (a);
- and
- c) reacting the isolated isomeric bromide product mixture of b) with a basic catalyst in an organic solvent wherein p-hydroxystrene is produced according to Formula II
- Formula II:
3 more elements
A method for the synthesis of p-acetoxystyrene comprising:
- a) reacting tyrosine in the presence of HBr and NaNO2 to form an isomeric bromide product mixture of 2-bromo-(3-p-hydroxyphenyl) propionic acid and 3-bromo-(2-p-hydroxyphenyl) propionic acid, according to Formula I:
- Formula I:
- b) isolating the isomeric bromide product mixture of (a);
- and
- c) reacting the isolated isomeric bromide product mixture of b) with a basic catalyst in an organic solvent wherein p-hydroxystrene is produced according to Formula II
- Formula II:
- and
- d) reacting the p-hydroxystyrene of step (c) with an acetylating agent wherein p-acetoxystyrene is formed.
5 more elements
Dependencies are inferred from the claim text.