CHEMIJA. 2010. Vol. 21. No. 2–4. P. 127–134 © Lietuvos mokslų akademija, 2010 © Lietuvos mokslų akademijos leidykla, 2010 Synthesis and structure of N-(4-bromophenyl)-N- carboxyethyl-β-alanine derivatives Kazimieras Anusevičius 1 , Vytautas Mickevičius 1 , Gema Mikulskienė 2 * 1 Department of Organic Chemistry, Kaunas University of Technology, Radvilėnų pl. 19, LT-50254 Kaunas, Lithuania 2 Department of Bioorganic Compounds Chemistry, Vilnius University Institute of Biochemistry, Mokslininkų 12, LT-08662 Vilnius, Lithuania New N-(4-bromophenyl)-N-carboxyethyl-β-alanine derivatives and products of their cy- clization were obtained and characterized by IR, mass, NMR spectra and elemental analy- sis. Data obtained in the studies are presented in the Experimental section, and the most significant cases are discussed. Key words: N,N-disubstituted-β-alanine, amides, cyclization, heterocycles, isomerism, NMR spectroscopy * Corresponding author. E-mail: gemam@bchi.lt INTRODUCTION Attention is being focused on β-amino acids as potential sub- stances for organic synthesis, bioorganic chemistry, medici- nal chemistry, and chemistry of natural compounds. In na- ture, β-amino acids are found in a free form. eir fragments are parts of peptides, coenzymes, alkaloids and antibiotics. Synthetic β-alanine derivatives are growth-stimulators of live organizms – plants and isolated animal cells, intermedi- ate products in the production of fungicides, drugs, polymer stabilizers. N-substituted amino acids are excellent synthons for the synthesis of 2-pyrrolidinone, imidazole, pyrrole, pyra- zine, thiazole, azetidine, pyrimidine, quinoline, diazepine and other heterocyclic systems exhibiting valuable practical properties [1–12]. e title compounds as uniform disubstituted amines possess a variety of fragments with different structural fea- tures predetermining their importance and specific spec- troscopic problems. Separate structural fragments of these compounds have been widely investigated [13–21]. Some of the synthesized compounds have in their molecules amide [13–16, 22–29] and azomethine [13–16, 29–31] fragments which cause the formation of isomers, whereas others con- tain different 5-membered heterocycles [32–42]. In spite of the identical substitution of amine, each of the side chains has a different spatial location. is fact was estimated from the optimized molecular models [43]. It should be noted that the molecules of the study compounds are in a dynamic equi- librium in solutions. e goal of the present work was synthesis of N-(4- bromophenyl)-N-carboxyethyl-β-alanine derivatives, prod- ucts of their cyclization, and validation of their structure. e structure elucidation was mainly focused on the analysis of NMR spectra. e assignment of NMR resonances was made on the basis of chemical shiſt theory, multiplicities, intensity and by comparison with similar spectral characteristics of structurally related compounds. RESULTS AND DISCUSSION One of the convenient methods of synthesis of N-aryl-β- alanines is interaction of aromatic amines with acrylic acid.