Tautomerism of 2‐amino‐2‐oxazolin‐4‐ones. <b>II</b>

Abstract

Abstract The study of the tautomerism of 2‐amino‐2‐oxazolin‐4‐one ( 1 ) and its methyl derivatives has been completed. The methylation of 1 gave 2‐imino‐3‐methyloxazolidin‐4‐one ( 4 ) and 2‐methyl‐amino‐2‐oxazolin‐4‐one ( 7 ). All attempts to isolate O ‐methyl derivatives failed. The uv, nmr, ir, and Raman spectra led to the definite conclusion, in agreement with the chemical evidence, that the 2‐aminooxazolinic form a , if it is theoretically possible, predominates in all compounds investigated. Otherwise the 2‐iminooxazolidinic form b predominates. The assignment of the carbonyl stretching is discussed on the basis of ir and Raman data. The nmr spectrum of compound 7 shows anomalous behaviour, most probably due to the existence of a monomer‐dimer equilibrium.