Reactions of p-Dimethylaminacinnamaldehyde with Urea, Thiourea and Their N-Alkyl/Aryl Derivatives

The reaction of p-dimethylaminocinnamaldehyde with  urea, thiourea  and their N- alkyl/aryl  derivatives in  acid  media   yields  colored products.  The structures  of  the colored products  are  illustrated  with chemical  and spectroscopic means. They  are found  to  be  shift- bases 4(a-f).the pinkish orange  color developed  in case  of urea  is  used for  the preparation of calibration  curves  for the  estimation of  urea present  in  biological  as  well  as non-biological fluids.  The  optimum amounts of p-dimethylaminocinnamaldehyde and HaSO. (36 N)   are 150 mg  /100  ml and  0.2  to 0.3 ml  in  80 ml  CH5OH.  These are quite  suitable quantities  for the reaction  to   proceed   favorably.  Moreover,  the   fluctuation of   the  pinkish  orange   color absorbance depends  upon the strength of acid.  The graphs are drawn using absorbance against urea concentration before and after heating solutions at 50°C.

U SHAUKAT ,I HUSSAIN ,