Oxidative functionalization of adamantanes (review)

Bagrii, E. I.; Nekhaev, A. I.; Максимов, А. Л.

doi:10.1134/s0965544117020128

Cited by 30 publications

(18 citation statements)

References 131 publications

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“…The functionalization of adamantane is critical for the development of new adamantane‐containing molecules. Significant progress has been made toward functionalization of the 1‐position of adamantane [1, 6, 7], however, the only common functionalizations of the 2‐position follow the production of 2‐adamantanone through oxidation of adamantane with H 2 SO 4 /SO 3 [8, 9]. Our synthetic toolkit for the adamantane framework would be enhanced if selective functionalization at the 2‐position of adamantane could be accomplished using targeted organometallic CH bond activation.…”

Section: Introductionmentioning

confidence: 99%

Group‐IV‐based selective CH bond activation of a diamondoid—A density functional theory study

Suleiman

Taullaj

Fekl

2021

Int J of Quantum Chemistry

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Selective synthetic modifications on diamondoids (well‐defined molecular nano‐diamonds) are difficult. Group IV organometallic complexes are promising systems for CH bond activation. We study the CH bond activation of the hard‐to‐activate CH2 positions of the adamantyl group (the smallest diamondoid) using density functional theory. As a platform for activation, we tether the adamantyl group to the cyclopentadienyl in a substituted bis‐cyclopentadienyl group IV metal diphenyl complex. The mechanism proposed in the experimental paper reporting the activation of C(Me)2‐Ph or t‐Bu groups using Zr(IV) involves an η2‐benzyne complex intermediate. Our computational work confirms the two‐step mechanism proposed for activation of C(Me)2‐Ph or t‐Bu using Zr(IV) and further extends it to Ti(IV) and Hf(IV). The first step forms the benzyne complex. In the second step, the cyclopentadienyl‐bound group is activated through a mechanism that closely resembles a σ‐bond metathesis when the benzyne complex is described as a metallacyclopropene We demonstrate through computations that the two‐step reaction can be successfully applied to the adamantyl group. CH bond activation of adamantyl is found to be thermodynamically and kinetically feasible. The important question of regioselectivity is addressed. We predict that α‐CH bond activation will be achievable with Ti (thermodynamic control), and selective γ‐CH bond activation with Zr (kinetic or thermodynamic control).

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Section: Introductionmentioning

confidence: 99%

Group‐IV‐based selective CH bond activation of a diamondoid—A density functional theory study

Suleiman

Taullaj

Fekl

2021

Int J of Quantum Chemistry

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“…The adamantane scaffold is widely used due to their steric [23,24], lipophilic [25] and rigid characteristics [26][27][28][29][30]. Derivatives that include heteroatoms have been synthesized, in addition to the well-known aza-(AZADO and hexamethylenetetramine) [31][32][33][34] and oxo-derivatives (tetrodotoxin) [35].…”

Section: Introductionmentioning

confidence: 99%

Complexes Between Adamantane Analogues B4X6 -X = {CH2, NH, O ; SiH2, PH, S} - and Dihydrogen, B4X6:nH2 (n = 1–4)

2020

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In this work, we study the interactions between adamantane-like structures B4X6 with X = {CH2, NH, O ; SiH2, PH, S} and dihydrogen molecules above the Boron atom, with ab initio methods based on perturbation theory (MP2/aug-cc-pVDZ). Molecular electrostatic potentials (MESP) for optimized B4X6 systems, optimized geometries, and binding energies are reported for all B4X6:nH2 (n = 1–4) complexes. All B4X6:nH2 (n = 1–4) complexes show attractive patterns, with B4O6:nH2 systems showing remarkable behavior with larger binding energies and smaller B···H2 distances as compared to the other structures with different X.

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“…Adamantane (Ad) with the same rigid and cubic core as POSS, but the good lipophilicity and biocompatibility, has been widely studied in medicine, functional materials as well as nanotechnology. Owing to their biocompatibility, low-toxicity and facile accessibility, Ad should be regarded as a promising scaffold for drug delivery systems [26,27,28]. For instance, Guo et al developed a series of pH-responsive star-shaped polymer Ad-(PCL- b -PDEAEMA- b -PPEGMA) 4 .…”

Section: Introductionmentioning

confidence: 99%

Nano-Carriers Based on pH-Sensitive Star-Shaped Copolymers for Drug-Controlled Release

et al. 2019

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Polymeric nano-carriers are considered as promising tools in biomedical applications due to multiple attractive characteristics including their low toxicity, high loading capacity, controlled drug release capabilities, and highly tunable chemical properties. Here, a series of pH-sensitive star-shaped copolymers, Ad-P[(EMA-co-MAA)-b-PPEGMA]4, was prepared via electron transfer atom radical polymerization (ARGETE ATRP) and selective hydrolysis. These star-shaped copolymers can be self-assembled into micelles (Dh = 150–160 nm) and their critical micelle concentrations (CMC) were estimated to be 3.9–5.0 mg/L. The pH-sensitiveness of the micelles was evidenced by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The maximal paclitaxel (PTX) loading efficiency (DLC) and entrapment efficiency (EE) were 18.9% and 36%, respectively. In vitro release studies revealed that about 19% of the PTX released at an acidic condition of pH 1.2 over 70 h, whereas more than 70% was released within the same time interval at pH 6.8. In vitro cytotoxicity suggested that the low cytotoxicity of the blank micelles, while the PTX-loaded micelles providing the cytotoxicity close to that of free PTX. These results indicated that this novel pH-sensitive nano-carriers have great potential applications for oral drug-controlled release.

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Oxidative functionalization of adamantanes (review)

Cited by 30 publications

References 131 publications

Group‐IV‐based selective CH bond activation of a diamondoid—A density functional theory study

Group‐IV‐based selective CH bond activation of a diamondoid—A density functional theory study

Complexes Between Adamantane Analogues B4X6 -X = {CH2, NH, O ; SiH2, PH, S} - and Dihydrogen, B4X6:nH2 (n = 1–4)

Nano-Carriers Based on pH-Sensitive Star-Shaped Copolymers for Drug-Controlled Release

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