A resident of Berkeley, Rapoport died at Kaiser Permanente Medical Center in Oakland, Calif. He was 83.

For several decades, he taught the important chemistry courses required by premedical and other life science students. He also taught upper-division undergraduate and graduate-level courses in natural products chemistry.

He was widely recognized for his work in pharmaceutical and medicinal chemistry, especially the synthesis of drug compounds. Among these were morphine, codeine and paralytic shellfish poison, called saxitoxin, in addition to antibiotics and anti-tumor compounds.

Appointed an instructor in chemistry at UC Berkeley in 1946, Rapoport was promoted through the ranks to professor in 1957. He retired from active service in 1989 and was awarded the Berkeley Citation in 1997. Rapoport remained actively engaged in research and in mentoring postdoctoral students until weeks before his death.

Rapoport was born in Brooklyn, N.Y., on Nov. 16, 1918. He attended high school in Atlantic City, New Jersey, and earned his BS in 1940 from the Massachusetts Institute of Technology with a major in chemistry. He remained at MIT for graduate work, receiving his PhD in organic chemistry in 1943.

His first position was with the Heyden Chemical Corporation, where he worked on the isolation, structure elucidation and synthesis of penicillin. In 1945, he accepted a National Research Council Fellowship at the National Institutes of Health in Bethesda, Md., where he carried out research on the synthesis of morphine derivatives.

During his scientific career, Rapoport mentored over 300 graduate students and postdoctoral fellows. He published more than 400 scientific articles, of which more than 75 appeared after his retirement.

Rapoport also was granted numerous patents in the general area of heterocyclic and natural products chemistry. He is noted for seminal work on the biosynthesis of morphine using radiolabeled carbon as a tracer element and for his contributions to the chemistry and biosynthesis of the porphyrins. He and his students carried out one of the first laboratory syntheses of the antitumor agent camptothecin.

In the 1970s, Rapoport teamed with his colleague John Hearst to develop the chemistry of psoralens, natural products which have found use for the deactivation of viruses and which served as the basis for formation of a successful private company, Cerus Corporation.

Throughout his career, Rapoport contributed to the organic chemistry profession in numerous ways, including serving as associate editor of the Journal of Organic Chemistry and as a member of the Medicinal Chemistry Study Section of the National Institutes of Health. He was highly valued and sought after as a consultant by numerous pharmaceutical research laboratories.

Among his awards were the 1985 Arthur C. Cope Scholar Award and the 1989 Ernest Guenther Award in the Chemistry of Essential Oils and Related Compounds, both from the American Chemical Society.

Rapoport is survived by his wife of 57 years, Sonya Rapoport; their daughter, Hava Rapoport, of Cordova, Spain; and sons, David of Berkeley and Robert of Cincinnati, Ohio.

A memorial service will be held on the UC Berkeley campus in 775 Tan Hall on March 29 at 4 p.m. The family requests that, in lieu of flowers, donations be made to the Henry Rapoport Endowed Chair in Organic Chemistry at UC Berkeley, or to the Berkeley Hillel.