Photochemie in der Vitamin D‐Reihe. I. Kinetik und Quantenausbeuten der Ergosterinbestrahlung bei λ = 253,7 nm

Abstract

Abstract Irradiation of Δ 5,7 ‐9α, 10β‐steroids in solution with λ = 253,7 nm yielded no Δ 5,7 ‐9β, 10α‐steroids and vice versa . No back reaction from precalciferol 2 to ergosterol could be detected by kinetic measurements. This leads to the conclusion that with the mercury resonance line only ring opening and 6,7‐ cis/trans isomerization but no ring closure occurs.