Obituary: Professor Sir Derek Barton

THE NOBEL Laureate Sir Derek Barton's published scientific works in organic chemistry spanned 58 years and ranged over vast areas of the subject. He was one of the greatest chemists of this century.

Unlike most scientists who prefer to remain as specialists, Barton had a mastery of both physical and organic chemistry and a breadth of interests which enabled him to turn to new fields, moving between topics, using the information gained from one study and then applying it to another, and then returning with more new ideas to the first. The areas which he left behind were always, of course, well ploughed by others.

He considered originality to be the most important quality. His advice to younger scientists was simply stated: "If you know, in the academic world, how to do a reaction you should not do it. You should only work on reactions that are potentially important and that you do not know how to do."

Barton was educated at Tonbridge School in Kent, and, after deciding that he did not want to follow his father into the family carpentry business, he enrolled to read Chemistry at Imperial College, London, because "the fees were higher and thereforeit had to be better". He was awarded the top first class honours BSc in 1940 and completed his PhD studies some two years later with Professor Sir Ian Heilbron. From 1942 to 1944, he was employed in secret wartime research and liked to hint that he developed a new range of invisible inks for use on human skin.

He was married in 1944 to Jeanne Wilkins and, after one year in the chemical industry with Albright and Wilson in Birmingham, he returned to Imperial College as assistant lecturer. To his dismay, he was required to teach, not as an organic chemist but in the more mathematical realms of physical chemistry. This was soon to prove a blessing in disguise when, in 1948, during the tenure of an ICI Research Fellowship, he published calculations on the preferred three-dimensional shape of an organic molecule.

His critical moment of insight came in the following year when he was a visiting lecturer at Harvard and attended a seminar in Professor Louis Fieser's group where discussions centred around unusual reactions of steroids. He disagreed with the conventional explanations, and recognised, because of his calculations, that there was an "obvious" relationship between the preferred shape of a molecule and its reactivity. His key paper on the subject, which came to be known as Conformational Analysis, was published in 1950 and led directly to the 1969 Nobel Prize for Chemistry, which he shared with the Norwegian physical chemist Odd Hassel.

On his return to the UK he moved to Birkbeck College, London, first as Reader and then, at the early age of 35, as Professor. In 1955, Barton was invited to become Regius Professor of Chemistry at Glasgow University, where space was at a premium andhe was installed in a glass partitioned office within his own research laboratory. From this excellent viewpoint, frequent and silent forays were made into the surrounding laboratory to startle his co- workers and enquire after the results of "our latest experiment".

The stay in Glasgow lasted only 18 months, however. The sudden death of Professor A.E. Braude precipitated his recall to his Alma Mater, and he was then to remain at Imperial College, ultimately as Hofmann Professor, for the next 20 years.

During the Fifties, he was also preoccupied with elucidating the detailed structure of natural products of plant and animal origin but he recognised the advent of new spectroscopic machines would soon make this a routine pursuit. He began to pursue "The Invention of New Chemical Reactions" as his intellectual challenge. These were to prove his preoccupation for almost another 40 years, and led to extraordinary productivity.

His original approach can be illustrated by a reaction now known as the Barton Nitrite Photolysis. It was unusual since it used light as the energy source at a time when most organic chemists were using heat, and also remarkable because species called "free radicals" were involved, while the traditional organic synthesis of the day was firmly rooted in the use of positively and negatively charged intermediates. Most importantly, it provided a method for preparing the steroid aldosterone at a time

when the world supply from natural sources was only a few milligrams. The power of the new reaction was demonstrated at a lecture when Barton produced a bottle containing 60 grams of the steroid.

Free radicals were also used in a theory called phenolic oxidative coupling which explained how complex stuctures such as morphine could be made inside plants. His "retreat and return" philosophy can be seen again in the Barton- McCombie free radical deoxygenation (1975) which was used to modify antibiotics and in the radical reagents called Barton Esters (1983). In these "firsts" and a host of other areas such as fluorination, Vitamin D chemistry, or penicillins, Barton made major contributions

which would be the single high point in the careers of most other organic chemists.

In the summer of 1977, Barton shocked the UK scientific establishment by announcing that, since he did not wish to retire at 65, he would move to the village of Gif-sur-Yvette near Paris as Director of the Institut de Chimie des Substances Naturelles, a world-renowned centrepiece of the French CNRS research system. His selection of France was made, not only because of his love of fine French wines and cheeses, but also for his French second wife, Christiane Cognet, whom he had married in 1969.

The years in Gif were extremely creative, and he adjusted easily to the French rhythm of life. Visiting speakers at the Institut were treated to sumptuous three-hour lunches prepared by Christiane, beginning with champagnes and ending with Sauternes. His co-workers invited to lunch could have problems when they returned to the lab at 3.30pm for another five hours' work.

This period also saw Barton begin to tackle his last great scientific challenge - the oxidation of saturated hydrocarbons. The problem here lies in converting basic petroleum products such as methane into feedstock for the fine chemical industry. Yet again, drawing inspiration from the chemical reactions occurring in nature, and thinking about the atmosphere of a primordial earth, he invented the Gif Oxidation, a combination of air, iron powder, hydrogen sulphide, vinegar and a dash of pyridine - and it worked.

In 1986, at the age of 68, and faced again by the prospect of an unwanted retirement, he made his final move and accepted an invitation to become Distinguished Professor of Chemistry at Texas A and M University, where he relished the competition of the American funding system.

Following the death of his wife Christiane in 1992, he married Judith Cobb and, from the home provided by Judy, and the two dogs on whom he doted, he continued to travel on the international science scene at a pace which would be the envy of those only half his age.

Derek Barton had a complex personality. The public persona presented in scientific meetings was of a rather forbidding figure, and his scientific rigour meant that he was always the first to ask probing questions after a lecture. Though he mellowed over the years, many of his colleagues were somewhat in awe of him, and found it hard to live up to his demanding standards, so that research discussions were often conducted on a polite and formal level.

In social gatherings, too, he was a little uncomfortable and keen to escape. To those who knew him well however, and with whom he could relax, an entirely different personality was revealed. At these times, he had a great sense of fun, loving to tell stories of people and places and revealing a surprisingly catholic range of interests in unsuspected areas such as literature and music. He was intensely proud of the world-wide family of his former colleagues and, as a "godfather", he always wishedto help them.

Barton liked to set himself new targets - and to meet them. One of these, made over 10 years ago, was to publish 1,000 research papers before the age of 80, and in this, he surpassed his goal: a remarkable achievement from a remarkable man.

Derek Harold Richard Barton, chemist: born Gravesend, Kent 8 September 1918; Assistant Lecturer, Department of Chemistry, Imperial College 1945- 46, ICI Research Fellow 1946-49; Reader in Organic Chemistry, Birkbeck College 1950-53, Professor of Organic Chemistry 1953-55; FRS 1954; Regius Professor of Chemistry, Glasgow University 1955-57; FRSE 1956; Professor of Organic Chemistry, Imperial College 1957-70, Hofmann Professor of Organic Chemistry 1970-78, Emeritus Professor of Organic Chemistry, London University 1978-98; Nobel Prize for Chemistry (jointly with Odd Hassel) 1969; Kt 1972; Director, Institut de Chimie des Substances Naturelles, CNRS 1977-85; Distinguished Professor of Chemistry, Texas A and M University 1986-95, Dow Distinguished Professor of Chemical Invention 1995-98; married 1944 Jeanne Wilkins (one son; marriage dissolved), 1969 Christiane Cognet (died 1992), 1993 Judith Cobb; died College Station, Texas 16 March 1998.