Zur Kenntnis der Dihydrovitamine D₂

Abstract

15 Lacton XIX, Sdp.15 160" C13H2003 (224.3) Ber. C 69.61 H 8.99 Gef. C 69.63 H 8.80 Lacton XXZ. 136 g Dipenten und 88 g Brenztraubensaure werden 3 Stdn. auf 145" erhitzt. Aus den 9.9 g der lactonischen Anteile 12) kann durch Umkristallisation aus Petrolather das scharf bei 140" schmelzende Lacton XXI erhalten werden. C13HZ003 (224.3) Ber. C 69.61 H 8.99 Gef. C 69.72 H 9.07 Lacton XXIZ. 2.40 g a-Cyclogeraniol und 1.7 ccm Dimethylbrenztraubensiiure werden 2 Stdn.auf 135-140" erhitzt. Aus dem lactonischen Anteil des Reaktionsproduktes k6nnen durch Umkristallisation aus Petrolather bei 0" Kristalle vom Schmp. 81 -83" erhalten werden. Es werden einfache Methoden zur Reindarstellung von Dihydrovitaminen D2 iiber neue Ester mitgeteilt. Die Eigenschaften von Dihydrovitamin Dz IV und einige neue Derivate werden beschrieben. Bei der Reduktion von Tachysterinz und Vitamin D2 mit Natrium und Alkoholen entsteht unter iiblichen Bedingungen als Hauptprodukt das Dihydrovitamin Dz I, dessen Konstitution durch Untersuchungen von A. WINDAUS, 0. LINSERT, A. LUTT-RINGHAUS und G. WEIDLICH 1). K. V.AUWERS und E. WOLTER z), S. v. REICHEL und M. DEPPE 3) und von A. WINDAUS und C. ROOSEN-RUNGE 4) weitgehend gesichert ist. Es sei indessen auf die interessante Beobachtung von P. WESTERHOF und J. A. KEVERLING BUISMAN 5 ) hingewiesen, da13 Dihydrovitamin Dz I nicht entsteht, wenn die Reduktion von Tachysterinz mit iiberschiissigem Lithium in fliissigem Ammoniak vorgenommen wird. Auch bei der katalytischen Hydrierung des Vitamins D2 mit 1 Mol Wasserstoff 1) Liebigs Ann. Chem. 492, 226 (1932).

THE CHEMISTRY AND CONFORMATIONAL AND BIOLOGICAL ANALYSIS OF VITAMIN D3, ITS METABOLITES AND ANALOGUES

“…Care should be exercised in comparing the nomenclature used here and in Figs. 2 and 5 with that of the earlier workers(Schubert & Wehrberger, 1956;von Werder, 1957;Westerhof & Keverling Buisman, 1957, 1959.…”

“…4) rather than the corresponding opposite chair form with the la-OH axial was suggested as the optimal molecular topology for intestinal calcium absorption. We also noted earlier that there was actually some controversy between von Werder (1957) and Westerhof & Keverling Buisman (1957, 1959 regarding the double bond stereochemistry of DHV,-IV. * Further, there has been some uncertainty regarding the stereochemistry at C,, of DHT, and the corresponding DHT,.…”

Vitamin D: Concerning the Relationship Between Molecular Topology and Biological Function

“…In this respect it has been used clinically for over a quarter of a century to treat a variety of vitamin Drelated diseases, including chronic renal failure and vitamin D-resistant rickets (37). By contrast, the less well-known H2-V2-IV, which was chemically characterized by von Werder (38),** is known to possess little if any biological activity (38,39). This result is in accord with our predictions, since H2T2 satisfies more fully the requirements of the three-dimensional "blueprint" 1' than does H2V2-IV.…”

The Action of Vitamin D and Parathyroid Hormone in Vitro on Calcium Uptake and Release by Kidney Mitochondria

“…However, this may be related to the fact that this agent, although possessing hypercalcemic activity at least equal to vitamin D, is much less potent as an antirachitic agent. 17 As illustrated in Table 2, a number of other hormones at concentrations of 3.3 X 10-6 to 5 X 10-7 M had no effect upon calcium release, whereas parathyroid hormone had a definite effect at a concentration of 4 X 10-7 Ml. It is of great interest that acetylated parathyroid hormone was effective; but is was less potent than the native hormone.…”