A series of new 2-(phenyl)-1,3- and 2-(phenyl)-1,3,3-tetramethylguanidines ( a-k ) were synthesized by reaction of different substituted aniline and urea derivatives in the presence of phosphorus oxychloride. The yields of products following extraction from toluene without further purification were of the order of 50-70%. We have found that adjusting of the pH at 8-9 in the work up process increases