Organische Phosphorverbindungen 44 Darstellung und Eigenschaften von Bis-(ß-chloräthyl)-phosphinsäure-Derivaten [1]

Reaction of ClCH₂CH₂PCl₂ with ethylene oxide gives the phosphonous acid ester ClCH₂CH₂P (OCH₂CH₂Cl)₂ which on heating to 120° rearranges to the phosphinic acid ester (ClCH₂CH₂)₂P(O)OCH₂CH₂Cl ( 3 ). Chlorination of 3 with PCl₅ in CCl₄-solution yields the phosphinic chloride (ClCH₂CH₂)P(O)Cl ( 4 ), which on treatment with P₂S₅ at 170° produces the thioderivative, (ClCH₂CH₂)₂P(S)Cl, (₅). Treatment of 4 and 5 with alcohols, mercaptanes, or amines in the presence of an acid binding agent leads to the corresponding phosphinic and thiophosphinic acid derivatives, (ClCH₂CH₂) P (X)Y, (X = O, S; Y = OR, SR, NR₂) ( 6 ). Reaction of 6 with excess base yields the corresponding divinylphosphinic and divinylthiophosphinic acid derivatives (CH₂ = CH)₂P (X) Y (X = O, S; Y = OR, SR, NR₂) ( 7 ). Bis-(ß-chloroethyl)-phosphinates, e. g. (ClCH₂CH₂)₂P (O) OEt, undergo a Michaelis-Arbuzov reaction when heated with phosphites to 160–170° to give bis-(phosphonylethyl)-phosphinates, e.g. (EtO) (O)P[CH₂CH₂CH₂P(O)(OEt)₂]₂ ( 8 ), which on hydrolysis with conc. HCl under reflux yield the corresponding acid HO₂P(CH₂CH₂PO₃H₂)₂.