I was born in Vukovar, Croatia, on August 1st, 1921., and I graduaded at the Faculty of Technology, University of Zagreb in 1946. During the period of 1946 to 1960 I worked in "Pliva", Pharmaceutical and Chemical Industry, Zagreb. Till 1950 my work was centered around the preparation of new tuberculostatic compounds of pyrrole-azo-phenylarsinic acid and on the stereochemistry of arsenobenzene derivatives. Of interest is the work published in 1951 on the "Observations on the Physico-Chemical Properties of Arsphenamine and Neoarsphenamine". It was proved the existence of cis- and trans-configuration of arsenobenzene. In 1950 I spent a year at Massachusetts Institute of Technology, Cambridge, Mass., and was co-author of the first total synthesis of -carothene. I obtaineded the PhD in Chemistry in 1952 at the University of Zagreb. The subject of doctoral thesis was synthesis of optically active sulfur containing beta-amino acids of the known absolute configuration: beta-homocystine, beta-homocysteine, beta-homomethionine, and beta-homodjencolic acid. The academic year 1952/1953 I worked with Professor Nicholas A. Milas at MIT, Cambridge on the preparation of muconyldimalonate derivatives. In Zagreb I continued the work on the synthesis and characterization of C40-terpenes, derivatives of carothenoids and was active in the synthesis of optically active polypeptides of beta-amino acids. In 1956 we prepared the first total synthesis of optically active chloramphenicol and correlated its configuration with D-serine. Academic year 1958/1959 I worked with Professor Roger Adams at the University of Illinois, Urbana, Ill., on the determination of configuration of C-1 and C-8 atoms in pyrrolizidine moieties of Monocrotaline, Retronecine and Heliotridone alkaloids. Of interest is our work on the preparation of optically active beta-substituted-beta-propiothiolactones of the known abspolute configuration. Polymerization of beta-propiothiolactones gave several optically active polymers which contain sulfur in the principal polymer chain. Many other optically active polymers were also prepared in our laboratories.
In 1960 I was appointed Director of the first modern well equipped Institute for Macromolecular Sciences. With many of my coworkers we carried out the pioneer work in macromolecular sciences, and Institute in Zagreb became a very active internationally recognized center of macromolecular sciences. In 1975 I was elected full Professor h.c. of stereochemistry at the University of Zagreb. My research work covers a wide field of macromolecular and organic chemistry: stereochemistry of natural products, synthesis of polyenes, and preparation and characterization of a large number of optically active polymers like polyamides, poly-beta-propiolactones, substituted polybutadienes, poly(phenylvinyl alkyl ethers) and alternating copolymers prepared through the participation of CT-complexes. During the last ten years we have actively worked on synthesis and characterization of liquid crystalline polymers which contain mesogenic groups in the side chain. Of special interest are polymers and copolymers which contain crown ethers as therminal groups in side chains. In collaboration with U-Mass in Amherst, Mass., we are working on the studies of the miscibility-immiscibility behaviour in polymer-polymer blends, and on the prediction of properties of alloys by the application of the mean field theory.
The research work which was performed with a large number of my coworkers was published in more than 200 scientific papers and 34 patents. I have also published many reviews, technical reports, and professional papers.
I initiated the organization of several local and international conferences and Summer Schools, and have participated as invited and plenary lecturer on many IUPAC conferences. As visiting Professor I was lecturing at the University of Massachusetts, Mass., and University of Mainz in Germany. I was honored with many awards and in 1980 I was elected a menber of the Croatian Academy of Sciences and Arts. Since 1985 I am retired and most of my recent activities are organized through the Croatian Academy of Sciences and Arts.
At the end of this biography I quote the last paragraph of a short introductory note published in Polymer Bulletin, Volume 5, Number 9/10, November 1981 at my 60th birthday: "One of the most significant features of Professor Fleš's activity is his ability to incorporate fundamental research into industrial application. Among his personal characteristics, the dominant ones are inventiveness and enthusiasm, which he conveys to his collaborators, devotion to research and application of the results of his investigations, and his ability to coordinate the work of large research groups".
Dragutin Fleš, F.C.A.