SYNTHESIS OF ACID-LABILE GEMINAL BIS- AND TRISPHOSPHONIC ACIDS¹

Abstract

Sodium salts (7, 8 respectively) of the unsaturated bisphosphonic acid 5 (2,6-di-tert-butyl-7,7-bis(phosphono)1,4-benzoquinone-4-methide) and the trisphosphonic acid 6 (4-hydroxy-3,5-di-tert-butylphenylmethane tris(phosphonic acid), were prepared by buffered hydrolysis of the corresponding trimethylsilyl esters. The structures of 7 and 8 were determined by ¹³C and ³¹P NMR analysis. Compound 8 is the first well-established example of a gem trisphosphonic acid salt.

Key Words:

• 7-phosphono-quinonemethide salts
• arylmethane trisphosphonate
• bromotrimethylsilane
• silyldealkylation
• ¹³C, ²³Na, ³¹P NMR data.