Facile synthesis of symmetric esters of alkylenebisphosphonic acids

Abstract

A facile synthesis of symmetric esters of C 1 -C 10 alkylenebisphopsphonic acids is disclosed in which a C 1 -C 10 alkylenebis(phosphonic dichloride) is reacted with an alcohol in the presence of a catalytic amount of 1 H-tetrazole and a base in an aprotic solvent to form a first reaction mixture. The first reaction mixture is maintained for a time period sufficient to form a C 1 -C 10 alkylenebis(chloro ester phosphonate) that is reacted under basic conditions with an excess of a hydroxylated compound to form a second reaction mixture that is itself maintained for a time period sufficient to form a C 1 -C 10 alkylenebis(ester phosphonate) partial ester, homoleptic tetraester or mixed tetraester. The material so formed can be recovered or used as is.

1 - 49 . (canceled)  
   
   
       50 . A compound of the formula H 2 C[PO(OR)OY)] 2    wherein R is a 2-ethylhexyl, 2,4,4-trimethylpentyl group or 3-(trimethylsilyl)propyl and    Y is (i) a hydrido, methyl, 2,4,4-trimethylpentyl or 3-(trimethylsilyl)propyl group when R is a 2,4,4-trimethylpentyl group or 3-(trimethylsilyl)propyl, or (ii) a methyl or 2-ethylhexyl group when R is a 2-ethylhexyl group.    
   
   
       51 . The compound according to  claim 50  wherein R is a 2-ethylhexyl group.  
   
   
       52 . The compound according to  claim 50  wherein Y is a methyl group.  
   
   
       53 . The compound according to  claim 50  wherein Y is a 2-ethylhexyl group.  
   
   
       54 . The compound according to  claim 50  wherein R is a 2,4,4-trimethylpentyl group.  
   
   
       55 . The compound according to  claim 50  wherein Y is a hydrido group.  
   
   
       56 . The compound according to  claim 50  wherein R is a 3-(trimethylsilyl)propyl group.  
   
   
       57 . The compound according to  claim 50  wherein Y is 3-(trimethylsilyl)propyl group.