A γ-cyclodextrin duplex connected with two disulfide bonds: synthesis, structure and inclusion complexes

Abstract

Per(2,3,6-tri-O-benzyl)-γ-cyclodextrin was debenzylated by DIBAL-H to produce a mixture of C6(I),C6(IV) and C6(I),C6(V) isomeric diols, which were separated and isolated. The C2-symmetrical C6(I),C6(V) diol was transformed into dithiol and dimerized to produce a γ-cyclodextrin duplex structure. A crystal structure revealed tubular cavity whose peripheries are slightly elliptically distorted. The solvent accessible volume of the cavity of the γ-CD duplex is about 740 Å(3). Due to this large inner space the duplex forms very stable inclusion complexes with steroids; bile acids examined in this study show binding affinities to the γ-cyclodextrin duplex in the range of 5.3 × 10(7) M(-1)-1.9 × 10(8) M(-1).

Inclusion complexes of 2-methoxyestradiol with dimethylated and permethylated β-cyclodextrins: models for cyclodextrin–steroid interaction

“…While being of significant interest in the context of modern anaesthesia [ 18 ], this more exotic supramolecular construct does not serve to illustrate CD–steroidal interactions that might be associated with the vast majority of bioactive steroids and our search further revealed that no representative CD–steroid structures containing more common CDs and steroidal guests (e.g., cortisone, prednisolone, estradiol, or their derivatives) have been reported hitherto. Very recently, an account of the crystal structure of a host comprising a γ-CD duplex system connected by two disulfide bonds that forms stable complexes with steroids appeared [ 19 ]. However, no crystal structure of any of its inclusion complexes was reported.…”

Secondary‐Rim γ‐Cyclodextrin Functionalization to Conjugate with C60: Improved Efficacy as a Photosensitizer

“…We have delineated a blueprint strategy consisting of deprotecting per‐ O ‐benzylated CDs using diisobutylaluminium hydride (DIBAL‐H), which proves to be very efficient because it allows access to CDs with one, two, and up to six different functions on their primary rim . These strategies have been applied to all three α‐, β‐, and γ‐CDs, but the regioselectivities for γ‐CDs can be low because of their larger size . In comparison with 6‐position, the regioselective functionalization on the secondary rim is more difficult.…”

“…Functionalization of the primary rim has been the most studied. [19] In comparison with 6-posi- tion, the regioselectivef unctionalization on the secondary rim is more difficult. Many strategies have been implementedt o mono-functionalize the primary rim.…”

“…[17][18][19] These strategies have been appliedt oa ll three a-, b-, and g-CDs, but the regioselectivities for g-CDs can be low because of their larger size. [19] In comparison with 6-posi-[a] X.…”

“…[17][18][19] These strategies have been appliedt oa ll three a-, b-, and g-CDs, but the regioselectivities for g-CDs can be low because of their larger size. [19] In comparison with 6-posi- tion, the regioselectivef unctionalization on the secondary rim is more difficult. However,t he strategies stay the same and the regioselective sulfonylation remains the main method, [20][21][22]30] especially for g-CD.…”