α-SUBSTITUTED PHOSPHONATES 68.¹ α-AMINOPHOSPHONATES AND PHOSPHONO-SUBSTITUTED HETEROCYCLES FROM DIETHYL [2,2,2-TRICHLORO-1-ISOCYANATO-ETHYL]PHOSPHONATE

Abstract

The easily accessible [2,2,2-trichloro-1-isocyanato-ethyl]phosphonate 1 reacts with aliphatic or aromatic amines to give the ureas 2,8. The reaction of these ureas with morpholine has been studied. Quite different reaction products have been isolated or observed depending on reaction time and the amine used for the urea formation. Oxazoles 4,10 are obtained if the ureas 2,8 were prepared from 1 and aliphatic amines or secondary amines. Surprisingly, ureas derived from 1 and aromatic primary amines furnish mixtures of oxazoles 4, guanidines 5, and imidazoles 6 via ring opening—closure sequences which have not been known so far. However, the urca 2i prepared from o-hydroxyaniline gives heterocyclic substituted α-aminophosphonate 7. Under acidic conditions the oxazoles 4,10 are hydrolysed to α-aminophosphonates 11.

Key Words:

• Phosphonates
• oxazoles
• imidazoles
• cyclization
• NMR data