September 1, 1906–December 9, 1997

BY WILLIAM SHIVE

KARL FOLKERS WILL BE remembered for his numerous major contributions and his able assistance to many other investigators over more than six decades of chemical research. His work on the structure, synthesis, and medical use of naturally occurring, biologically active compounds, such as alkaloids, antibiotics, B-vitamins, hormones, and co-enzymes, has had lasting impact. He played unique roles in the structural determination and synthesis of B-vitamins, and especially the isolation and determination of the chemical nature of vitamin B₁₂. These studies provided key advances toward making B-vitamins available for nutritional supplementation. His capacity for effective collaboration contributed to the structure determination and synthesis of the first hypothalamic hormone, provided evidence for the last position assignment of substituent groups in coenzyme Q₁₀, resulted in the synthesis of coenzyme Q₉, and generated the structure determination and synthesis of the isoprenoid precursor, mevalonic acid. His awards and honors encompassed almost all of those in his field of research. However, his highest valuation was placed on his long-term relationships—with his multiple collaborators and friends with whom he worked and consulted. He was especially aware and moved