Conformation of 1,5-Bis(16-oxobeyeran-19-oyloxy)-3-oxapentane in CCl4

Abstract

1,5-Bis(16-oxobeyeran-19-oyloxy)-3-oxapentane in carbon tetrachloride exists mainly in tweezers-like conformations where the isosteviol fragments hang over each other.By the X-ray diffraction method we previously found [1, 2] that 1,5-bis(16-oxobeyeran-19-oyloxy)-3-oxapentane (I) in crystal has a tweezers-like structure where the tetracyclic hydrocarbon frameworks hang over each other, thus forming an intramolecular cavity. It seemed reasonable to elucidate which conformation is inherent to compound I in solution. For this purpose we used the dipole moment technique including experimental measurement of the dipole moment by the second Debye method and calculation of the theoretical dipole moment according to the vector additivity scheme [3].

Novel Macrocyclic Derivatives of Diterpenoid Isosteviol

“…In principle this is not unusual case as the literature has provided the example of how one binuclear isosteviol derivative remained tweezer-like structure when going from a crystal to a greatly diluted reaction solution. [13] Probably the sandwich-like structure of diacid 6 is so thermodynamically stable in solution that it is still retained in the course of the reaction with ditosylate of ethylene glycol because the molecular structure of macrocycle 15 also resembles slightly distorted sandwich (Figure 6). The surprising thing was that the reaction of diacid 5 having unfolded structure of 3b type (Figure 3) in crystal [10] with the ditosylate of ethylene glycol afforded macrocycle 9 which also had sandwich-like structure according X-ray data ( Figure 7).…”

“…The mixture was refluxed for 26 h. After removing the solvent under reduced pressure, a precipitate was purified using chromatography. 2,11,14,12(16,10,13, 2,11,14,12(16,10,13, 2,11,14,12(16,10,13, 2,11,14,23,26,35,38,12,25,36(16, cyclooctatetracontaphane-3,10,13,24,27,34, 37,48-octaone (10 2,11,14,21,24,33,36,12,23,34(16, cyclotetratetracontaphane-3,10,13,22, 25,32,35,44-octaone (11 2,11,14,17,20,29,32,12,19,30(16, cyclohexatriacontaphane-3,10,13,18,21, 28,31,36-octaone (12 2,13,16,14(16,…”

Macrocyclic Derivatives of Diterpenoid Isosteviol with Hydrazide and Hydrazone Moieties

“…Then the solvent was removed under reduced pressure, a precipitate was recrystallized from methanol, dried in vacuo, and the pure product was obtained. 24,39,4,11,12,27,28,35,14,25,38(4α,16)tetra (19-nor-ent-beyerana)cyclooctatetracontaphane -2,5,10,13,16,23,26,29,34,37,40,47-dodecaone (16 (17). Anhydrous hydrazine (0.4 ml, 11 mmol) was added to the …”