GUANIDINE COMPOUNDS: IV. ACETYLATION OF SOME ALKYL-SUBSTITUTED GUANIDINES WITH ACETIC ANHYDRIDE AND ETHYL ACETATE

The acetylation of some mono-, N,N-, and N,N′-dialkylguanidines was studied using ethyl acetate and acetic anhydride. Except for the N,N-dialkylguanidines, the action of ethyl acetate on the free bases gave monoacetyl derivatives. Acetic anhydride with the acetate salts gave diacetyl derivatives with monoalkylguanidines, acetamido-1,3,5-triazines with N,N-dialkylguanidines, and unstable di- and tri-acetyl derivatives with N,N′-dialkyl-guanidines. The assignment of symmetrical structures to the mono- and tri-acetyl derivatives and an asymmetrical structure to the diacetyl derivatives was supported by nuclear magnetic resonance spectra. The ultraviolet spectra of the monoacetyl derivatives exhibited one peak in the region 230-235 mµ whilst the diacetyl derivatives showed two peaks in the regions 220-230 mµ and 253-263 mµ. Some comments are made on the infrared spectra of these compounds.