Calixarenes. 16. Functionalized calixarenes: the direct substitution route

Gutsche, C. David; Pagoria, Philip F.

doi:10.1021/jo00350a071

Cited by 160 publications

(91 citation statements)

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“…The cone-conformer of tetrabenzylcalixarene (2) was synthesized as described (20). The benzyl groups prevent internal rotations of the calix [4]arene macrocycle and permanently fixed its conformation.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and assembly of self-complementary calix[4]arenes.

Shimizu

Rebek

1995

Proc. Natl. Acad. Sci. U.S.A.

283

138

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A calix [4]arene was designed to reversibly dimerize and form an egg-shaped enclosure. Adhesive interactions in the assembly were provided by four self-associating ureas, which form a cyclic array containing 16 hydrogen bonds. The synthesis was completed in four steps from theEvidence for dimerization of the calixarene tetraurea was provided by 'H NMR, mass spectrometry, and the observation of encapsulated molecules. The resulting cavity was of sufficient size to capture guests such as ethyl benzene andp-xylene.

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Section: Resultsmentioning

confidence: 99%

Synthesis and assembly of self-complementary calix[4]arenes.

Shimizu

Rebek

1995

Proc. Natl. Acad. Sci. U.S.A.

283

138

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“…The conversion of aminoethyl into guanidinoethyl groups at the upper rim led to the, except for the 6,6′-dimethyl-2,2′-bipyridyl-derivative (28b), in excellent antimycobacterial activities for the unsubstituted (28a), the 5,5′-dimethyl-2,2′-bipyridyl (28c) and the 4,4′-dimethyl-2,2′-bithiazolyl (28d) analogues, having 0.8, 0.8 and 1.6 μm MIC values, respectively, comparable to some of the available commercial antituberculosis agents ( Table 1). The compounds with high activity were also tested against the isoniazid-resistant strain MYC5165 that showed highly interesting micromolar or submicromolar MIC and IC 50 , confirming their much more activity than isoniazid (see Table 1). The evaluation of these compounds against both Gram-positive and Gram-negative bacteria resulted in good to excellent antibacterial activity against one or more of the tested strains [88] .…”

Section: Lower-and Upper-rim-functionalized Calix[4]arenesmentioning

confidence: 74%

“…[49] With the easy availability of p-position of calixarene by de-tert-butylation, a number of procedures have been developed for p-functionalization of calixarenes. For example, N-bromosuccinimide has been used for tetrabromination of the tetramethyl ether of calix [4]arene in high yield, [50] while Br 2 has been used for B,D-dibromination of the A,C-dialkyl ether. [51] Similarly, Friedel-Crafts and other electrophilic aromatic substitution conditions were applied to introduce alkyls, NO 2 , SO 3 H, SO 2 Cl, CHO, COR, COAr, CH 2 Cl, ArN 2 , etc.…”

Section: Calix[4]arene-an Overviewmentioning

confidence: 99%

Functionalized calix[4]arenes as potential therapeutic agents

2017

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Calixarenes, composed of phenolic units linked by methylene bridges at the 2,6-positions, represent a versatile class of macrocyclic compounds in supramolecular chemistry that can host small molecules or ions in their well-defined hydrophobic cavities. In recent years, it has been recognized that this class of compounds has the potential to serve as platform for the design of biological active compounds. Therefore, the calixarenes functionalized with different pharmacophoric groups have been synthesized as target structure by many researchers and were further evaluated for their biological activities. Owing to their promising biological activities such as antiviral, antibacterial, antifungal, and anticancer, the functionalized calixarenes are recently receiving increased attention from pharmaceutical/medicinal chemistry community. In this review, we summarize and discuss the synthetic approaches and the biological potential of functionalized calixarenes, mainly focusing on the selected recent studies for a comprehensive and target-oriented information, which could help in the design and synthesis of new therapeutic agents leading to the development of clinically viable drugs based on these macrocyles. K E Y W O R D Sbiological activity, calixarenes, cone conformation, functionalization, upper/lower rim/annulus

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“…A paramagnetic calix [4]arene has been prepared through selective bromine-lithium exchange of 5,11,17,23-tetrabromocalix [4]arene by n-BuLi [2]. It has been reported that bromination of 26,28-dimethoxycalix [4]arene with Br 2 only occurred on the para position of the phenoxyl groups to give the corresponding dibromo compound [1], whereas complete bromination of 25,26,27,28-tetramethoxycalix [4]arene with NBS occurred on the upper rim to produce the tetrabromo compound [3]. We recently synthesized a new tetrabromo calix [4]arene, which has two phenoxyl and two methoxyl groups, with complete bromination on the para position.…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of 5,11,17,23-tetrabromo-25,27-dihydroxy- 26,28-dimethoxycalix[4]arene, C30H24Br4O4

Yang

Liu

et al. 2006

Zeitschrift Für Kristallographie - New Crystal Structures

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Source of materialThe precursor compound 25,27-dihydroxy-26,28-dimethoxycalix[4]arene was obtained according to [1]. Then the compound was brominated with N-bromosuccinimide (NBS) in the molar ratio of 1:9 in butanone at room temperature. After reacting for three days, the title compound was obtained and recrystallized from chloroform/methanol. Experimental detailsThe small N gt /N param ratio and the large R1 value are caused by the poor quality of the crystals. DiscussionThe . We recently synthesized a new tetrabromo calix[4]-arene, which has two phenoxyl and two methoxyl groups, with complete bromination on the para position. The molecular structure of the title compound displays approximate twofold symmetry. Two kinds of hydrogen bonds exist in the crystal structure. One is the intermolecular hydrogen bond between O2 and Br3 i , which distance is 3.25 Å. Another one is the intramolecular hydrogen bonding between two hydroxyl and two methoxy groups at the lower rim, where the distances are 2.61 Å for O1···O2, 2.85 Å for O2···O3, 2.68 Å for O3···O4, and 2.95 Å for O4···O1. Therefore the cone conformation of the calix[4]-arene cavity is retained and pinched due to the intramolecular hydrogen bonds. The angles are 76.9°for ÐO4···O1···O2, 103.9°f or ÐO1···O2···O3, 77.6°for ÐO2···O3···O4, and 99.8°for ÐO3···O4···O1. The four dihedral angles are 116.6°, 130.7°, 114.9°, and 126.4°for the respective phenyl rings of C2C7, C9C14, C16C21, and C2328 to the reference plane defined by the bridging C atoms. The distances from C1, C8, C15 and C22 to the reference plane are 0.083 Å, 0.081 Å, 0.079 Å and 0.080 Å, respectively.

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Calixarenes. 16. Functionalized calixarenes: the direct substitution route

Cited by 160 publications

References 0 publications

Synthesis and assembly of self-complementary calix[4]arenes.

Synthesis and assembly of self-complementary calix[4]arenes.

Functionalized calix[4]arenes as potential therapeutic agents

Crystal structure of 5,11,17,23-tetrabromo-25,27-dihydroxy- 26,28-dimethoxycalix[4]arene, C30H24Br4O4

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