Synthesis, structure and properties of N-alkoxy-N-(1-pyridinium)urea salts, N-alkoxy-N-acyloxyureas and N,N-dialkoxyureas

N-Alkoxy-N-(1-pyridinium)urea salts 3, 4 have been prepared, the conversions of N-acetoxy-N-methoxyurea 7 into N,N-dimethoxyurea 8 and of N-n-propyloxy-N-(1-pyridinium)-N',N'-dimethylurea chloride 6 into N,N-dimethoxy-N',N'-dimethylurea 11 were carried out. A high pyramidality of the amide nitrogen in O–N–X groups [X = N⁺C₅H₅, OMe, OC(O)C₆H₄Cl-p] has been revealed by XRD studies of ureas 3b, 8 and N-p-chlorobenzoyloxy-N-n-butyloxyurea 9.