Patent ID: 7317119

Claim:
A process for the preparation of 9,10-dihydro-9-oxa-10-organyloxy-phosphaphenanthrene-10-oxide or -thione and derivatives of Formula Vla or Vlb comprising the steps of: (a) reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide or a derivative of same according to Formula Ia or Ib, in which R 1 to R 8 , independently of each other, are a hydrogen atom, halogen atom or a hydrocarbon group, the hydrocarbon groups optionally containing one or more heteroatoms selected from oxygen, nitrogen, sulphur, phosphorus, silicon and halogen, and two or more radicals R 1 to R 8 being optionally linked with formation of one or more cycles, in the presence of at least one mono- or polyhydric alcohol of Formula IIIa R 11 (OH) y (IIIa) in which R 11 is a mono- or polyvalent hydrocarbon group which optionally contains one or more heteroatoms selected from oxygen, nitrogen, sulphur, phosphorus, silicon and halogen, and y is 1 to 10, with at least one ortho ester of Formula II R 9 C(OR 10 ) 3 (II) in which R 9 is a hydrogen atom or a hydrocarbon group and the radicals R 10 are the same or different hydrocarbon groups which optionally contain one or more heteroatoms selected from oxygen, nitrogen, sulphur, phosphorus, silicon and halogen, to form a first intermediate product, wherein the product obtained in step (a) has the Formula IVa or IVb in which the radicals R 1 to R 11 and y have the meanings as stated above; (b) transforming the intermediate product from step (a) by addition of oxidation agent into 9,10-dihydro-9-oxa-10-organyloxyphosphaphenanthrene-10-oxide or -thione or a derivative of same substituted on the phenyl groups, wherein the product obtained in step (b) has the Formula VIa or VIb in which R 1 to R 11 and y have the same meanings as stated above and Z is oxygen or sulfur.