Carbon-13 magnetic resonance spectroscopy of steroids. Estra-1,3,5(10)-trienes

Abstract

The natural abundance carbon-13 magnetic resonance spectra of estra-l,3,5(10)-triene and 17 derivatives are reported. Substituent effects upon the chemical shifts of each carbon atom are determined and discussed in terms of factors known to influence 13C chemical shifts.

13C‐FT‐NMR‐Untersuchungen an Steroiden. Konfigurationszuordnung an 16, 17‐disubstituierten Δ1, 3, 5 (10)‐östratrienen und Δ5(6)‐Androstenen

“…Zusammenfassend kann festgestellt werden, daB sich die 4 stereoisomeren iG-CH,OAc, 17-0Ac-disubstituierten Androstene und Ostratriene an Hand der 13C-chemischen Verschiebungen der C-Atome C-18 und (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17) Es kann erwartet werden, daB sich das angegebene Verfahren zur Konfigurationszuordnung auch anderer Substituenten und Steroidstrukturen einsetzen l&Bt und eine detaillierte Analyse der konfigurationsabhangigen Verschiebungseff ekte weitere Aussagen iiber die sterischen Verhaltnisse am Steroidgerust ermoglichen sollte. Die Untersuchungen werden in dieser Richtung rortgesetzt.…”

“…Bei einem Vergleich der MeBwerte fur die Verbindung 11 (3-Metho~y-17~-hydroxy-A~,~,~(~0)ostratrien) mit den fur das gleiche Steroid in [ 3 ] angegebenen Ergebnissen fallt auf, da13 nahezu alle Signale in [3] bis zu maximal 1,9 ppm nach tieferem Feld verschoben sind. Losungsmitteleffekte allein (in[3] wurde Dioxan als Losungsmittel verwendet) konnen fur diese Abweichungen nicht verantwortlich gemacht werden, zumal die starksten Differenzen fur die unpolaren gessttigten Gerustatome C-9 und C-11 beobachtet werden. Die Abweichungen dieser beiden Signale [d(C-9) = 44,9 ppm, 6(C-11) = 28,l ppm] konnen jedoch verringert werden, wenn sic mit den Signalen fur C-l3(6 = 43,9 ppm) bzw.…”

X-Ray crystal structure analysis and 13C NMR investigation of estriol 16- and 17-monoglucuronide derivatives

“…The trans relationship of all adjacent protons observed in the latter ring is in accordance with the large coupling constants ( > 6.0 Hz) obtained by 'H NMR ~pectroscopy.~,'~ Two intermolecular approaches are observed between O( 1) and O(11) of a second molecule and between O(8) and the partially weighted water molecule O( 14) at distances of 3.23 and 3.13 A, respectively. These may be contrasted with other similar steroid molecules "-13 which lack the bulky substituent at C (17) but where shorter H-bonding contacts, in the range 2.62-2.98 A, are observed.…”

“…Of greatest interest are the arrangements adopted by the substituents on ring D. The carbohydrate moiety is attached in the p position so that O(3) is in the trans position relative to O(2). Steric pressures between H( 17) and H( 1'), which are cis to one another, are relieved by slight twists about the 0(3)-C (17) and 0(3)-C(1') bonds so that a contact distance of 2.24 A is achieved. This close approach is reflected in the crosscorrelation of H (17)…”

Correlation of ring-junction stereochemistry in A-aromatic octahydrophenanthrenes with 13C n.m.r. chemical shifts

“…The chemical shifts observed for the C-7, C-8, C-I I , and C-12 carbons also could not be evaluated substantially without the effects of substituents attached to the C- 13 The signal values for the remaining C-1, C-6, C-9, and C-10 carbons, which are moderately sensitive to structural modification, seem to be parameters of choice which correlate them directly with the B/C ring-junction configurations. These data are summarized in Table 2, which can be used diagnostically to predict the ring stereochemistry of the octahydrophenanthrene system.…”