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Carlos E Silva et al.
The journal of physical chemistry. A, 114(37), 10097-10109 (2010-08-26)
This work presents the crystal structure and the investigation under a supramolecular perspective of a squaric acid derivative obtained from the replacement of the hydroxyl groups by anilines. The squaraine obtained (1,2-dianilinesquaraine) crystallizes in the Pbcn space group, in a
Tsonko Kolev et al.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 72(3), 502-509 (2008-12-23)
We report the synthesis, spectroscopic and structural elucidation of two prolinamide derivatives of squaric acid, i.e. prolinamide ester amide of squaric acid ethyl ester (1) and prolinamide diamide of squaric acid dihydrate (2). Both compounds crystallize in non-centrosymmetric space groups
Heterocycles, 35, 1149-1149 (1993)
Cristina Avonto et al.
Toxicology and applied pharmacology, 289(2), 177-184 (2015-10-13)
Skin sensitization is an important toxicological end-point in the risk assessment of chemical allergens. Because of the complexity of the biological mechanisms associated with skin sensitization, integrated approaches combining different chemical, biological and in silico methods are recommended to replace
Jeremiah P Malerich et al.
Journal of the American Chemical Society, 130(44), 14416-14417 (2008-10-14)
Thioureas represent the dominant platform for hydrogen bond promoted asymmetric catalysts. A large number of reactions, reported in scores of publications, have been successfully promoted by chiral thioureas. The present paper reports the use of squaramides as a highly effective
Igor Bensemann et al.
Organic & biomolecular chemistry, 1(8), 1425-1434 (2003-08-22)
The preparation and crystal structures of fourteen complexes of N,N'-bis(2-pyridyl)aryldiamines with dicarboxylic acids and two complexes with squaric acid are reported. The recognition between the carboxylic acids and the 2-aminopyridine units occurs through the formation of the cyclic R(2)2 (8)
Construction of a 3D array of cadmium (ii) using squarate as a building block.
Maji, Tapas Kumar, et al.
CrystEngComm, 155-158 (2001)
Elena Sanna et al.
Organic letters, 12(17), 3840-3843 (2010-08-10)
A minimalist squaramide-based chemodosimeter for Cu(2+) is described. Upon selective chelation to 2, Cu(2+) induces the formation of a highly colored zwitterionic radical, which is kinetically stable for hours. The presence of a radical is confirmed by EPR and ESI-MS.
Carsten Dingels et al.
Chemistry (Weinheim an der Bergstrasse, Germany), 18(52), 16828-16835 (2012-11-09)
The covalent attachment of poly(ethylene glycol) (PEG) to therapeutically active proteins (PEGylation) has become an important method to deal with the pharmacological difficulties of these polypeptides, such as short body-residence times and immunogenicity. However, the derivatives of PEG used for
Dawei Cui et al.
Chemical communications (Cambridge, England), 47(4), 1348-1350 (2010-11-18)
We report a class of water-soluble and -stable cyclic amino squarates that ligate with cysteine or lysine residues without side-products in an entirely aqueous environment. The ligations include addition-elimination reactions that are promoted by water in a way similar to
Shingo Saito et al.
Analytical sciences : the international journal of the Japan Society for Analytical Chemistry, 29(1), 157-159 (2013-01-11)
In this paper, the characterization and application of the "PectI" (polymer-enhanced capillary transient isotachophoresis) technique for the separation and detection of same genus, gram-positive bacteria, Bacillus globigii (Bg) and Bacillus subtilis, is demonstrated by employing a boronic acid-functionalized squarylium dye
Natasha Ramroop-Singh et al.
Bioorganic chemistry, 38(5), 234-241 (2010-07-06)
Three novel metal squaric acid-peptide complexes, SQI-SQIII were prepared by addition of indium triflate or zinc chloride to the previously reported compounds [1], 3-(hydroxymethylamino)-4-(l-isoleucine methyl ester)-3-cyclobutene-1,2-dione (squarate 1), and 3-(hydroxymethylamino)-2-(l-isoleucine methyl ester)-4-thioxo-2-cyclobuten-1-one (squarate 2). The structures of SQI-SQIII were elucidated
M Burak Onaran et al.
The Journal of organic chemistry, 70(26), 10792-10802 (2005-12-17)
[structure: see text] A series of squaric acid-peptide conjugates were synthesized and evaluated as inhibitors of MMP-1. The cyclobut-3-enedione core was substituted at the 3-position with several functional groups, such as -N(alkyl)OH, -NHOH, and -OH, that are designed to bind
Tsonko M Kolev
Protein and peptide letters, 15(7), 713-718 (2008-09-11)
The IR-spectroscopic and structural elucidation of tetrapeptide glycyl-(L)-prolyl-glycyl-glycine and its hydrogensquarate was performed by employing linear-polarized IR-spectroscopy of oriented colloid suspensions in nematic host as well as mass spectrometry. Quantum-chemical ab initio calculations were carried out in order to evaluate
Georgiana Petrache et al.
Revista medico-chirurgicala a Societatii de Medici si Naturalisti din Iasi, 113(3), 915-920 (2010-03-03)
We comprehensively characterized the human (h), guinea pig (gp), canine (c) and rat (r) H2R species isoforms on Spodoptera frugiperda (Sf9) cell membranes expressing H2R-G(Salpha) with respect to the interaction with new ligands derived from squaramide. Antagonist potencies were determined
Jian Xie et al.
Organic letters, 6(1), 83-86 (2004-01-03)
[structure: see text] Protein tyrosine phosphatases (PTPases) are important targets in medicinal chemistry. These enzymes play a role in a number of human diseases, including type II diabetes and infection by Yersinia pestis, the causative agent of bubonic plague. Derivatives
Julie Charton et al.
Bioorganic & medicinal chemistry letters, 18(18), 4968-4971 (2008-09-02)
We report here the parallel synthesis of 200 compounds based on squaric acid template. These compounds are obtained via a one-step solution-phase procedure starting from three squaric acid N-hydroxylamide esters precursors. The set of diverse reagents qualified (amines, anilines, amino-alcohols
Frederik Wurm et al.
Chemical communications (Cambridge, England), 49(71), 7815-7817 (2013-07-26)
A water-soluble squaric acid dialkyl diester derivative is presented, which enables one-pot, two-step amine-selective protein conjugation reactions with (functional) amines in water. This reagent not only allows all-aqueous protein modifications, but also tolerates e.g. hydroxyl groups and can also be
Vijayakumar Ramalingam et al.
Organic letters, 10(15), 3315-3318 (2008-07-02)
Environment-sensitive binding of anions to synthetic receptors is important for the functional mimicry of ion channels. We describe new squaramide-based chloride ion receptors whose anion binding cavity can be opened and closed by using carbonyl groups as valves. In nonpolar
H S Seleem et al.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 78(3), 1097-1104 (2011-01-18)
A novel chelating agent (Sqtsc; H(4)L) bearing both hard and soft donor atoms was synthesized by the condensation of squaric acid with thiosemicarbazide. The ligand has two symmetrical sets of donor atoms (SNO), therefore, it was allowed to react with
Synthesis, spectral properties, and detection limits of reactive squaraine dyes, a new class of diode laser compatible fluorescent protein labels
Oswald et al.
Bioconjugate chemistry, 11(3), 438-438 (2000-05-23)
Carsten Grabosch et al.
Chembiochem : a European journal of chemical biology, 12(7), 1066-1074 (2011-04-08)
Bacteria use long proteinaceous appendages, called fimbriae or pili, to adhere to the surfaces of their host cells. Widely distributed among the Enterobacteriacae are type 1 fimbriae that mediate mannose-specific bacterial adhesion through the lectin FimH, located at the fimbrial
David M S Martins et al.
Journal of the American Chemical Society, 131(11), 3884-3893 (2009-03-04)
We have applied a combination of spectroscopic and diffraction methods to study the adduct formed between squaric acid and bypridine, which has been postulated to exhibit proton transfer associated with a single-crystal to single-crystal phase transition at ca. 450 K.
Georgiana Petrache et al.
Revista medico-chirurgicala a Societatii de Medici si Naturalisti din Iasi, 114(1), 255-259 (2010-06-01)
We characterized the pharmacological activity of some new fluorescent and nonfluorescent ligands derived from aminopotentidine and squaramide with respect to the interaction with human (h) and guinea pig (gp) H2R species isoforms on Spodoptera frugiperda (Sf9) cell membranes expressing H2R-Gsalpha
Charles M Marson
Chemical Society reviews, 40(11), 5514-5533 (2011-08-13)
Contemporary medicinal chemistry faces diverse challenges from several directions, including the need for both potency and specificity of any therapeutic agent; the increasingly demanding requirements of low toxicity shown across all patients treated; and the need for novelty in intellectual
Frank Lovering et al.
Bioorganic & medicinal chemistry, 17(9), 3342-3351 (2009-04-15)
A novel series of inhibitors for mitogen activated protein kinase-activated protein kinase 2 (MK-2) are reported. These squarate based inhibitors were identified via a high-throughput screen. An MK2 co-structure with the starting ligand was obtained and a structure based approach
Zorka Bobcheva et al.
Journal of enzyme inhibition and medicinal chemistry, 26(4), 587-591 (2011-03-29)
A series of 4-alkylamino-2-ethoxycyclobut-3en-1,2-diones has been synthesized, characterized and their inhibitory effect on pancreatic lipase (PL) was evaluated. The compound 1 has shown relatively high potency (IC(50) = 0.11 mM) compared with the most effective anti-obesity drug, tetrahydrolipstatin (Orlistat) (IC(50) value = 0.08 mM). The compounds
Eun-Mi Lee et al.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 95, 25-28 (2012-05-23)
A squarylium (SQ) dye was synthesized by the reaction between squaric acid and 2,3,3-trimethylindolenine and its anion sensing properties were investigated using absorption and emission spectroscopy. This chemosensor exhibited high selectivity for CN(-) as compared with F(-), CH(3)CO(2)(-), Br(-), H(2)PO(4)(-)
Bojidarka B Ivanova et al.
Amino acids, 39(1), 309-314 (2010-01-19)
The title compound, 2-(phenylethyl)ammonium hydrogensquarate hemihydrate, was synthesized and structurally and spectroscopically characterized by a single crystal X-ray diffraction and solid-state polarized IR spectroscopy of oriented colloids in a nematic host. The crystal structure consists of two crystallographically independent 2-(phenylethyl)ammonium
Wen Yang et al.
Organic letters, 15(6), 1190-1193 (2013-03-08)
An efficient asymmetric cascade sulfa-Michael/Michael addition reaction catalyzed by a chiral bifunctional squaramide-tertiary amine catalyst has been developed. This organocatalytic cascade reaction provides easy access to highly functionalized chromans with three contiguous stereocenters, including one quaternary center. In addition, a
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