Reaktion #346799

Reaktionsgleichung

4-hydroxy-3-methoxy-benzaldehyde

sodium acetate

N-acetylglycine

acetic anhydride

→

2-methyl-4-(3-methoxy-4-acetoxy-benzylidene)-5(4H)-oxazolone

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstige2 hours
2. 2
   Sonstigethe crystals which have separated out
3. 3
   Filtrationare filtered off
4. 4
   Waschenwashed with water

Vorschrift

152 g (1mol) of 4-hydroxy-3-methoxy-benzaldehyde, 41 g of sodium acetate, 80 g of N-acetylglycine and 242 g of acetic anhydride are heated together for 30 minutes to 100° C. and then for 21/2 hours to the refluxing temperature. The resulting solution is cooled to 0° C. and the crystals which have separated out are filtered off and washed with water. The crude 2-methyl-4-(3-methoxy-4-acetoxy-benzylidene)-5(4H)-oxazolone thus obtained is heated to the boil with 1,400 ml of acetone and 545 ml of water for 15 hours under a reflux condenser. Thereafter, the acetone is largely distilled off, whereupon the product crystallises out. After filtration, and washing with acetone, 4-acetoxy-α-acetylamino-3-methoxycinnamic acid of melting point 205°-206° C. is obtained.

Quelle