Marinus Los

Born: September 18, 1933 | Ridderkerk, NL

Marinus Los discusses his early life in the Netherlands and England, as well as his education at Edinburgh University, where he first became interested in biochemistry and received a Ph.D. in that field. Los took a research position at the National Research Council in Canada and conducted research in the structural chemistry of alkaloids and plants before moving on to a research chemist position at American Cyanamid Company. Los discusses his research on imidazolinoes, a type of plant growth regulators, and its results: the herbicides Assert, Arsenal, and Pursuit, as well as a National Medal of Technology. 

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Interview Details

Interview no.: Oral History 0127
No. of pages: 57
Minutes: 183

Interview Sessions

James J. Bohning
17 January 1995
American Cyanamid Company, Princeton, New Jersey

Abstract of Interview

The interview begins with Dr. Marinus Los' description of his family's origins in The Netherlands. When he was two years old, his family moved to England, where he received his early education during World War II. Encouraged by his older brother, Los studied chemistry at Edinburgh University, where he first became interested in biochemistry. He conducted his PhD research on heterocyclic analogs of azulene under W. H. Stafford. Stafford encouraged Los to study at the National Research Council in Canada. There, he conducted research in the structural chemistry of alkaloids and plants under Leo E. Marion. In 1960, Los became a research chemist at Lederle Laboratories, now a division of the American Cyanamid Company. Under Milon E. Bullock, he conducted early research on insect control via an insect molting hormone discovered by Dr. Peter Karlson. Los also worked on a synthetic steroid project involving anabolic steroids and artificial insemination for cows. He briefly returned to Edinburgh University's Department of Pharmacology to organize a research program in prostaglandins. On returning to American Cyanamid, led at the time by George J. Sella, Jr. , Los switched to research on herbicides. In his research on plant growth regulators (PGRs), Los's work on imidazolinones led to the herbicides Assert, Arsenal and Pursuit. This work won him the National Medal of Technology. Los ends the interview by discussing his later career as first Senior Group Leader and then Research Director, focusing on his approach to the encouragement of teamwork at American Cyanamid. 


Year Institution Degree Discipline
1955 University of Edinburgh BSc Chemistry
1957 University of Edinburgh PhD Organic Chemistry

Professional Experience

National Research Council Canada

1958 to 1960
Research Fellow

University of Edinburgh

1969 to 1970
Senior Research Fellow, Department of Pharmacology

American Cyanamid Company

1960 to 1971
Senior Research Chemist
1971 to 1984
Group Leader, Organic Synthesis
1984 to 1986
Senior Group Leader, Herbicide Discovery
1986 to 1988
Manager, Crop Protection Chemical Discovery
1988 to 1992
Associate Director, Crop Sciences
1992 to 1996
Research Director, Crop Sciences Discovery


Year(s) Award

Boots Drummond Prize in Biochemistry, Edinburgh University


Blandfield Prize in Chemistry, Edinburgh University


Cyanamid Scientific Achievement Award, American Cyanamid Company


Cyanamid President's Award for Excellence in Agriculture, American Cyanamid Company


Distinguished Inventor, Intellectual Property Owners, Inc.


Thomas Alva Edison Patent Award, New Jersey Research & Development Council


National Medal of Technology


Achievement Award, Industrial Research Institute


Perkin Medal, Society of Chemical Industry (American Section)


Award for Creative Invention, American Chemical Society

Table of Contents

Family Background and Early Education

Family origins in The Netherlands. Immigration to England. Early education during World War II. Influence of older brother. Introduction to science in high school.

Undergraduate Education

Studies in chemistry at Edinburgh University. Burgeoning interest in biochemistry. Projected reunion of graduating class in honors chemistry. First paper with Gerald O. Aspinall on carbohydrate chemistry in plants. Influence of Edmond L. Hirst.

Graduate Education

Focus on heterocyclic chemistry. Ph.D. work with W. H. Stafford on heterocyclic analogs of azulene. Research on hydrazine. Award from Industrial Research Institute. Importance of anomalies in research.

National Research Council

Research in structural chemistry. Leadership of Leo E. Marion. Papers with Marion and O. E. Edwards on structures derived from alkaloids and plants. Research on the structure of hydroxylycoctonine.

Early Career at Lederle Laboratories

Decision to pursue career in industrial science. Interactions with Milon W. Bullock. Early research on insect molting hormone. Development of synthetic anabolic steroids and artificial insemination of cows. Attitude towards publication at Lederle.

Work on Prostaglandins at Edinburgh University

Move to Edinburgh University. Start of research program in prostaglandins. Reasons for return to industry.

Herbicide Development at American Cyanamid

Research on plant growth regulators (PGRs) and phthalimides. Development of imidazolinones, leading to Avenge. Random screening approach for new herbicides. Discovery of cyclohexyl derivative of phthalimides, leading to Assert, Arsenal, and Pursuit. Joint project with Molecular Genetics. Organizational expansion.

Later Career

Promotion to Senior Group Leader. Cyanamid's support of research and development. Influence of George J. Sella, Jr. Views on teamwork and managing creative people. Award of the National Medal of Technology.


About the Interviewer

James J. Bohning

James J. Bohning was professor emeritus of chemistry at Wilkes University, where he had been a faculty member from 1959 to 1990. He served there as chemistry department chair from 1970 to 1986 and environmental science department chair from 1987 to 1990. Bohning was chair of the American Chemical Society’s Division of the History of Chemistry in 1986; he received the division’s Outstanding Paper Award in 1989 and presented more than forty papers at national meetings of the society. Bohning was on the advisory committee of the society’s National Historic Chemical Landmarks Program from its inception in 1992 through 2001 and is currently a consultant to the committee. He developed the oral history program of the Chemical Heritage Foundation, and he was CHF’s director of oral history from 1990 to 1995. From 1995 to 1998, Bohning was a science writer for the News Service group of the American Chemical Society. In May 2005, he received the Joseph Priestley Service Award from the Susquehanna Valley Section of the American Chemical Society.  Bohning passed away in September 2011.