CHARLES REES was one of Europe’s most outstanding organic chemists and, although well past official retirement, he was active in his research until a few weeks before his death. His field was heterocyclic chemistry, which is the study of molecules containing rings made up of carbon atoms interspersed variously by other atoms such as nitrogen, oxygen and sulphur. Such molecules are of great importance and are all-pervading in modern life, but particularly in biology and medicine.

Rees’s forte was the synthesis of hitherto unknown systems and the understanding of how such systems behaved and how they are put together, thus bringing order and predictability to a complicated field. He also made extraordinary discoveries in the field of reactive intermediates, a species that did not obey what were perceived to be the laws of chemical bonding. These species, having lifetimes in chemical reactions of a millionth of a second, not only provide the clues to the details of the pathways taken in chemical reactions but can be tamed to produce new as well as known systems.

His encyclopaedic knowledge and gifted insight were remarkable. Time and again in presentations by others puzzled by a chemical conundrum Rees would spring to his feet and explain it all. These attributes put him in great demand as a consultant to industry. He was much involved in research leading to cimetidine, the first of the new generation of peptic ulcer drugs. This was a heterocyclic chemical which, he delighted in pointing out, had put hundreds of specialist surgeons out of work, saved the NHS a billion pounds and given enormous relief to countless people. Such was his expertise that he was in industrial demand right to the end, his latest consultancy arriving in his 79th year, paralleling his leading appearances at international scientific conferences.

Rees was the best and most effective type of academic, refusing to succumb to the exhortations of politicians that academics should turn themselves into pseudo-industrialists. Rather, he showed by example that his job was to make discoveries that no one knew were there to be discovered; to use his knowledge in inspiring the young and assisting the real industrialists to reach their targets in the marketplace. Indeed, inspiration of others was another of his immense talents. He was one of the most brilliant lecturers in the world of chemistry. His students adored him and his peers listened with admiration.

Charles Wayne Rees was born in Cairo, where his father was a serving soldier. The family eventually settled in Aldershot. He matriculated at Farnham Grammar school, thence to RAE Farnborough, where he was employed as a lab technician. Coming up the hard way, he studied for the higher school certificate at night school and was subsequently admitted to read chemistry at what was then University College, Southampton. He obtained a first in the external honours degree of London University and his PhD at Southampton. His first academic post was as assistant lecturer at Birkbeck College, which was followed by a lectureship at King’s College London.

At the time King’s was a hotbed of talent under the leadership of Donald Hey. As chair of chemistry, Rees went to Leicester in 1965, then to Liverpool in 1969, where he became Heath Harrison Professor in 1977 and finally to the Hofmann chair of organic chemistry at Imperial College in 1978, subsequently becoming emeritus.

He was a delightful, amusing and charming man with a mischievous sense of humour. He and his wife of 53 years, Patricia, were generous hosts and generations of students will remember their kindness and hospitality. He delighted in his knowledge of the organic chemistry of the grape, as he put it.

He published more than 500 original scientific papers, several key books and received many honours and prizes. He was elected FRS in 1974 and received the CBE in 1995.

He is survived by his wife and three sons.

Professor Charles Rees, CBE, FRS, organic chemist, was born on October 15, 1927. He died on September 21, 2006, aged 78.