Substituted furanones and process for preparing 3,4-dihydro-alpha-pyrones and substituted furanones

摘要

1. Process for the production of 3,4-dihydro-alpha-pyrones of the formula see diagramm : EP0075680,P5,F18 wherein R**1 , R**2 and R**3 can be the same or different and stand for hydrogen or alkyl groups with 1 to 10 C-atoms, characterised in that a compound of the formula see diagramm : EP0075680,P5,F4 wherein R**1 , R**2 and R**3 have the aforementioned meaning and R**4 denotes the residues see diagramm : EP0075680,P5,F6 see diagramm : EP0075680,P5,F7 see diagramm : EP0075680,P5,F8 or -O-R**5 wherein R**5 stands for lower alkyl groups, is heated.