One of the fundamental conditions for life on Earth is the ability of carbon atoms to bind each other to a practically unlimited extent. They form chains, often very branched, but also rings and net-works. The number of carbon compounds is thus very large - some years ago I saw the number two million - and many new ones are discovered or prepared every day. It is obvious that a multitude of different substances are required to build up a living organism and make it function.
The structure of carbon compounds, often called organic compounds, is, however, governed by rather simple principles. To describe an organic molecule, we have first the constitution, which can be said to represent the ground-plan. Next we have the configuration, which deals with the question of right or left. In the case of unsymmetrical objects like gloves or shoes there must exist a right form and a left form and the same is true for unsymmetrical molecules. What is then the conformation, which is of interest here to-day?
A molecule is not, in general rigid. There is a certain flexibility, which may, perhaps, be called limpness or floppyness. Certain distances and angles are invariable and the chain must not be broken, but it may bend, turn or twist in different ways. In ring-shaped molecules, the flexibility is more restricted. Small rings of three, four of five atoms are rather rigid and planar. Six carbon atoms permit a certain flexibility and large rings may be rather floppy. Complicated molecules with net-works of several rings are often more rigid. The rings check or lock each other. The conformation is the shape, which the molecule really assumes, utilizing the flexibility. It may be said that conformational analysis deals with the mode of behaviour of floppy molecules.
Metaphorically one could say that the molecule tries to arrange itself in the most comfortable way. It will avoid crowding and strain and must consider that certain groups may attract or repel each other.
Often a great number of conformations are possible, but some are more stable than others. These are statistically favoured. A ring of six carbon atoms can have two conformations, known as the chair and boat forms, which easily interchange. At room temperature, a molecule changes its conformation about a million times in a second. One of the conformations is, however, strongly predominant (about 99%). Professor Hassel has carried out fundamental investigations on this system and shown how heavy or bulky groups, attached to the carbon atoms, take up their positions relative to the ring and to each other.
The conformation is of great importance for the mode of reaction of the molecules. Reactive groups may be easily accessible, or they may also be more or less blocked by other groups. Knowledge of the conformation is therefore of great importance for explaining or predicting the mode of reaction of a certain molecule. It is always a good thing to know if an experiment has any chance of success.
Geometry in three dimensions is not very popular. I suppose that no one will mind if I refrain from discussing special cases in detail and from describing the physico-chemical methods used in conformational analysis.
In the development of scientific ideas it is generally possible to trace contributions, elements of thought, from many sides. But often the decisive advances, the intellectual syntheses from different thoughts and suggestions can be attributed to one or two scientists, who stand out from the others. Professor Hassel's elegant work on six-membered rings, carried out with ever increasing precision, has laid a solid foundation for a dynamic chemistry in three dimensions. Professor Barton has generalized, opening wider perspectives and deducing the consequences for many complicated ring systems, which play an important role in living nature. Let me only mention the ring system of the steroids, which is found in the bile acids, necessary for digestion, in sex hormones, cortisone, digitalis glycosides and cholesterol but also in the lather-forming saponins and in the special venoms of potato-tops and toads.
Professor Barton. In the classical work "The Conformation of the Steroid Nucleus" you have advanced the leading principles of conformational analysis. In this paper you have also drawn attention to the notable researches of Hassel, which have thrown considerable light on these more subtle aspects of stereochemistry. Your ideas were soon accepted and they play a fundamental role in organic chemistry of today. According to a prominent fellow scientist, your paper represents the first real advance in stereochemistry since the theory of Van 't Hoffand Le Bel, i.e. since 1874. I have no objections.
In recognition of your services to Chemical Science, the Royal Academy has decided to confer upon you the Nobel Prize. To me has been granted the privilege of conveying to you the most hearty congratulations of the Academy.
Professor Hassel. Not very long ago, organic chemists spoke of free rotation. Gradually they found that the rotation is restricted and that this fact is important. Many workers have contributed to the development, but in our opinion your work on the cyclohexane system is of outstanding importance. In your work on decaline, you have also taken the important step to polycyclic systems and pointed the way for coming development. In recognition of your services to Chemical Science, the Royal Academy has decided to confer upon you the Nobel Prize. To me has been granted the privilege of conveying to you the most hearty congratulations of the Academy.
Professor Barton. On behalf of the Academy I invite you to receive your prize from the hands of His Majesty the King.
Derek Harold Richard Barton was born on 8 September 1918, son of William Thomas and Maude Henrietta Barton. In 1938 he entered Imperial College, University of London, where he obtained his B.Sc.Hons. (1st Class) in 1940 and Ph.D. (Organic Chemistry) in 1942. From 1942 to 1944 he was a research chemist on a government project, from1944-1945 he was with Messrs. Albright and Wilson, Birmingham. In 1945 he became assistant lecturer in the Department of Chemistry of Imperial College, from 1946-1949 he was I.C.I. Research Fellow. In 1949 he obtained his D.Sc. from the same University. During 1949-1950 he was Visiting Lecturer in the Chemistry of Natural Products, at the Department of Chemistry, Harvard University (U.S.A.). In 1950 he was appointed Reader in Organic Chemistry and in 1953 Professor at Birkbeck College. In 1955 he became Regius Professor of Chemistry at the University of Glasgow, in 1957 he was appointed Professor of Organic Chemistry at Imperial College, which position he still holds.
In 1950, in a brief paper in Experientia entitled "The Conformation of the Steroid Nucleus", Professor Barton showed that organic molecules in general and steroid molecules in particular could be assigned a preferred conformation based upon results accumulated by chemical physicists, in particular by Odd Hassel. Having chosen a preferred conformation, it was demonstrated that the chemical and physical properties of a molecule could be interpreted in terms of that preferred conformation. In molecules containing fixed rings, such as the steroids, there resulted a simple relationship between configuration and conformation, such that configurations could be predicted once the possible conformations for the products of a reaction could be analysed. Thus the subject "conformational analysis" had begun. Barton later determined the geometry of many other natural product molecules using this method. Conformational analysis is useful in the elucidation of configuration, in the planning of organic synthesis, and in the analysis of reaction mechanisms. It will be fundamental to a complete understanding of enzymatic processes.
Prof. Barton was invited to deliver the following special lectures: 1956, Max Tischler Lecturer at Harvard University; 1958, First Simonsen Memorial
Lecturer of the Chemical Society; 1961, Falk-Plaut Lecturer, Columbia University; 1962, Aub Lecturer at Harvard Medical School; Renaud Lecturer at Michigan State University; Inaugural 3 M's Lecturer, University of Western Ontario; 1963, Hugo Müller Lecturer of the Chemical Society; 3 M's Lecturer at the University of Minnesota; 1967, Pedler Lecturer of the Chemical Society; 1969, Sandin Lecturer at the University of Alberta; 1970, Graham Young Lectureship, Glasgow.
In 1958 Prof. Barton was Arthur D. Little Visiting Professor at Massachusetts Institute of Technology, Cambridge, Mass.; in 1959 Karl Folkers Visiting Professor at the Universities of Illinois and Wisconsin.
In 1954 Derek Barton was elected to Fellowship of the Royal Society, in 1956 he became Fellow of the Royal Society of Edinburgh; in 1965 he was appointed member of the Council for Scientific Policy of the U. K.; in 1969 he became President of Section B, British Association for the Advancement of Science, and President of the Organic Chemistry Division of the International Union of Pure and Applied Chemistry.
Professor Barton holds the following honours and awards: 1951, First Corday-Morgan Medal of the Chemical Society; 1956, Fritzsche Medal of the American Chemical Society; 1959, First Roger Adams Medal of the American Chemical Society; 1960, Foreign Honorary Member of the American Academy of Arts and Sciences; 1961, Davy Medal of the Royal Society; 1962, D. Sc.h.c. Montpellier; 1964, D. Sc.h.c. Dublin; 1967, Honorary Fellow of the Deutsche Akademie der Naturforscher "Leopoldina"; 1969, Honorary Member of Sociedad Quimica de Mexico; 1970, D.Sc.h.c. St. Andrews: Fellow of Birkbeck College; Honorary Member of the Belgian Chemical Society; Foreign Associate of the National Academy of Sciences; Honorary Member of the Chilean Chemical Society; D.Sc.h.c., Columbia University, New York; 1971, First award in Natural Product Chemistry, Chemical Society (London); D.Sc.h.c., Coimbra (Portugal); Elected Foreign Member of the Academia das Ciencias de Lisboa; 1972, D. Sc.h.c. University of Oxford; Longstaff Medal of the Chemical Society.
Derek Barton was first married to Jeanne Kate Wilkins but this marriage was later dissolved. He is now married to Christiane Cognet, a Professor of the Lycée français de Londres. He has one son, W.G.L. Barton, by his first marriage.