22323-82-6Relevant articles and documents
Efficient resolution of rac-2,3-O-isopropylideneglycerol by enantioselective inclusion crystallization with the chiral diol CYTOL
Vinogradov, Maxim G.,Kurilov, Dmitry V.,Ferapontov, Vladimir A.,Heise, Glenn L.
, p. 125 - 126 (2003)
The efficient resolution of rac-2,3-O-isopropylideneglycerol (IPG) using enantioselective two-step inclusion crystallization with the chiral diol CYTOL has been performed.
Design and preparation of a novel prolinamide-based organocatalyst for the solvent-free asymmetric aldol reaction
Martins, Rafaela de S.,Pereira, Mathias P.,de Castro, Pedro P.,Bombonato, Fernanda I.
, (2019/12/24)
The preparation of four novel organocatalysts as highly diastereo and enantioselective catalysts for the solvent-free asymmetric aldol reaction was described. These organocatalysts were synthesized in eight steps applying simple and commercially available starting materials. The best results were obtained for the proline-derived catalyst, providing access to the desired adducts in up to 95% yield, 1:19 syn/anti and 98% e.e. Moreover, even sterically bulky aldehydes and substituted cyclohexanones were well tolerated. DFT calculations and control experiments indicated that several hydrogen bonding interactions between the aldehyde and the enamine intermediate are responsible for the stereoselective chiral induction process and that the trifluoroacetate counter-anion is crucial for the attainment of higher stereoselectivities.
Synthesis and antimicrobial screening of novel 1,3-dioxolanes linked to N-5 of 5H-1,2,4-triazino[5,6-b]indole-3-thiol
Ramadan, El Sayed,Rasheed, Hanaa A.,El Ashry, El Sayed H.
, p. 1 - 10 (2019/05/14)
Synthesis of 1-[(2,2-dimethyl-1,3-dioxolan-4-yl)methyl]-1H-indole-2,3-dione (10) was achieved by coupling 1H-indole-2,3-dione (16) with (R)-(2,2-dimethyl-1,3-dioxolan-4-yl)methyl 4-methylbenzenesulfonate (15) in the presence of sodium hydride in dry N,N-dimethylformamide at room temperature in a closed Erlenmeyer flask. Condensation of 10 with hydrazinecarbothioamide in water afforded the thiosemicarbazone derivative 17; its subsequent cyclization with potassium carbonate in water gave the corresponding thione 18 in good yield. The 3-allylthio and 3-benzylthio derivatives 20 and 21 were also prepared by alkylating thiol 19 with alkyl halides in aqueous sodium hydroxide or coupling of 3-(allylthio/benzylthio)-5H-1,2,4-triazino[5,6-b]indoles (23 and 24) with compound 15 in NaH/DMF. Compound 20 was isomerized to a mixture of geometrical isomers (E/Z)-5-[(2,2-dimethyl-1,3-dioxolan-4-yl)-methyl]-3-(prop-1-en-1-ylthio)-5H-1,2,4-triazino[5,6-b]indoles (25 and 26), evidenced by their 1H- and 13C-NMR spectra taken in deuterodimethyl sulfoxide. Structural elucidation of the synthesized compounds was realized using FT-IR, 1H-NMR, 13C-NMR, mass spectrometry and elemental analysis. The newly synthesized compounds were found to possess moderate inhibitory activity against the fungus Candida albicans compared to clotrimazole as reference control. Compounds 10, 17, 19, 20, 21, 23 and 24 had mean growth inhibition zones (IZ) and minimal inhibitory concentrations (MIC) in the range of 12–15 mm and 31.25–200 μg mL-1, respectively, with inhibition levels in the range 70.58–88.23 %. Compound 19 exhibited moderate activity against Gram-positive bacteria Staphylococcus aureus relative to imipenem as the standard drug. All compounds were inactive against Escherichia coli and Pseudomonas aeruginosa.
A stereospecific carboxyl esterase from Bacillus coagulans hosting nonlipase activity within a lipase-like fold
De Vitis, Valerio,Nakhnoukh, Cristina,Pinto, Andrea,Contente, Martina L.,Barbiroli, Alberto,Milani, Mario,Bolognesi, Martino,Molinari, Francesco,Gourlay, Louise J.,Romano, Diego
, p. 903 - 914 (2018/01/22)
Microbial carboxylesterases are important biocatalysts that selectively hydrolyze an extensive range of esters. Here, we report the biochemical and structural characterization of an atypical carboxylesterase from Bacillus?coagulans (BCE), endowed with high enantioselectivity toward different 1,2-O-isopropylideneglycerol (IPG or solketal) esters. BCE efficiently catalyzes the production of enantiopure (S)-IPG, a chiral building block for the synthesis of β-blockers, glycerophospholipids, and prostaglandins; efficient hydrolysis was observed up to 65?°C. To gain insight into the mechanistic bases of such enantioselectivity, we solved the crystal structures of BCE in apo- and glycerol-bound forms at resolutions of 1.9 and 1.8??, respectively. In?silico docking studies on the BCE structure confirmed that IPG esters with small acyl chains (≤?C6) were easily accommodated in the active site pocket, indicating that small conformational changes are necessary to accept longer substrates. Furthermore, docking studies suggested that enantioselectivity may be due to an improved stabilization of the tetrahedral reaction intermediate for the S-enantiomer. Contrary to the above functional data implying nonlipolytic functions, BCE displays a lipase-like 3D structure that hosts a “lid” domain capping the main entrance to the active site. In lipases the lid mediates catalysis through interfacial activation, a process that we did not observe for BCE. Overall, we present the functional-structural properties of an atypical carboxyl esterase that has nonlipase-like functions, yet possesses a lipase-like 3D fold. Our data provide original enzymatic information in view of BCE applications as an inexpensive, efficient biocatalyst for the production of enantiopure (S)-IPG. Database: Coordinates and structure factors have been deposited in the Protein Data Bank (www.rcsb.org) under accession numbers 5O7G (apo-BCE) and 5OLU (glycerol-bound BCE).
Enzyme-Mediated Directional Transport of a Small-Molecule Walker with Chemically Identical Feet
Martin, Christopher J.,Lee, Alan T. L.,Adams, Ralph W.,Leigh, David A.
supporting information, p. 11998 - 112002 (2017/09/07)
We describe a small-molecule "walker" that uses enzyme catalysis to discriminate between the relative positions of its "feet" on a track and thereby move with net directionality. The bipedal walker has identical carboxylic acid feet, and "steps" along an isotactic hydroxyl-group-derivatized polyether track by the formation/breakage of ester linkages. Lipase AS catalyzes the selective hydrolysis of the rear foot of macrocyclized walkers (an information ratchet mechanism), the rear foot producing an (R)-stereocenter at its point of attachment to the track. If the hydrolyzed foot reattaches to the track in front of the bound foot it forms an (S)-stereocenter, which is resistant to enzymatic hydrolysis. Only macrocyclic walker-track conjugates are efficiently hydrolyzed by the enzyme, leading to high processivity of the walker movement along the track. Conventional chemical reagents promote formation of the ester bonds between the walker and the track. Iterative macrocyclization and hydrolysis reactions lead to 68% of walkers taking two steps directionally along a three-foothold track.
Synthesis of dihydrosterculic acid-based monoglucosyl diacylglycerol and its analogues and their biological evaluation
Srikanth, Vudhgiri,Prasad,Poornachandra,Phani Babu,Ganesh Kumar,Jagadeesh,Jala, Ram Chandra Reddy
, p. 134 - 145 (2016/01/16)
In the present study, Lactobacillus plantarum glycolipid (GL1) molecule in β-configuration and its fatty acid analogues were synthesized using trichloroacetimidate methodology. The β-configuration of the GL1 molecule was unambiguously assigned by NMR studies using 2D-ROESY (NOE) and J-coupling analysis. Dihydrosterculic acid was synthesized using Furukawa's reagent and the selective esterification of dihydrosterculic acid at C-3 position of glycerol was achieved with EDC-HCl at 0 °C. In vitro cytotoxicity of the GL1 molecule and its fatty acid analogues was evaluated against DU145, A549, SKOV3 and MCF7 cell lines. Among all the synthesized molecules, the GL1 molecule and compound 7d showed moderate activity, while the compound 7b showed promising activity against all the tested cell lines with IC50 values of 20.1, 18.2, 19.1 and 17.6 ?1/4M, respectively. In addition, all tested compounds showed poor cytotoxicity against normal HUVEC cells. The MCF7 cells when treated with compound 7b showed lower bromodeoxyuridine incorporation levels as compared to untreated cells, suggesting that the compound 7b was highly effective and inhibited the cell proliferation. In addition, the compounds showed significant increase in caspases 3 and 9 levels by inducing apoptosis in MCF 7 cells.
Formal synthesis of nanaomycin D via a Hauser-Kraus annulation using a chiral enone-lactone
Hassan, Najmah P.S.,Naysmith, Briar J.,Sperry, Jonathan,Brimble, Margaret A.
, p. 7137 - 7143 (2015/08/24)
Abstract A formal total synthesis of nanaomycin D has been achieved. The strategy employed made use of a one-pot cyclisation-stereoselective reduction of a hydroxyketone to install the pyranonaphthalene moiety after execution of a Hauser-Kraus annulation using a chiral enone-lactone as the Michael acceptor to append the γ-lactone ring. The chirality in the chiral enone-lactone was established using a Sharpless asymmetric dihydroxylation. The enone-lactone used herein represents an attractive chiral synthon for the construction of other γ-lactone containing pyranonaphthoquinones such as griseusin A and crisamicin A.
Crystal structures of two Bacillus carboxylesterases with different enantioselectivities
Rozeboom, Henriette J.,Godinho, Luis F.,Nardini, Marco,Quax, Wim J.,Dijkstra, Bauke W.
, p. 567 - 575 (2014/02/14)
Naproxen esterase (NP) from Bacillus subtilis Thai I-8 is a carboxylesterase that catalyzes the enantioselective hydrolysis of naproxenmethylester to produce S-naproxen (E > 200). It is a homolog of CesA (98% sequence identity) and CesB (64% identity), both produced by B. subtilis strain 168. CesB can be used for the enantioselective hydrolysis of 1,2-O-isopropylideneglycerol (solketal) esters (E > 200 for IPG-caprylate). Crystal structures of NP and CesB, determined to a resolution of 1.75 A and 2.04 A, respectively, showed that both proteins have a canonical α/β hydrolase fold with an extra N-terminal helix stabilizing the cap subdomain. The active site in both enzymes is located in a deep hydrophobic groove and includes the catalytic triad residues Ser130, His274, and Glu245. A product analog, presumably 2-(2-hydroxyethoxy)acetic acid, was bound in the NP active site. The enzymes have different enantioselectivities, which previously were shown to result from only a few amino acid substitutions in the cap domain. Modeling of a substrate in the active site of NP allowed explaining the different enantioselectivities. In addition, Ala156 may be a determinant of enantioselectivity as well, since its side chain appears to interfere with the binding of certain R-enantiomers in the active site of NP. However, the exchange route for substrate and product between the active site and the solvent is not obvious from the structures. Flexibility of the cap domain might facilitate such exchange. Interestingly, both carboxylesterases show higher structural similarity to meta-cleavage compound (MCP) hydrolases than to other α/β hydrolase fold esterases.
Optically active monoacylglycerols: Synthesis and assessment of purity
Chen, Chao-Yuan,Han, Wei-Bo,Chen, Hui-Jun,Wu, Yikang,Gao, Po
, p. 4311 - 4318 (2013/07/26)
Despite their simple structures, synthesis of 1(or 3)-acyl-sn-glycerols remains a challenge that cannot be ignored because of facile acyl migrations, which not only complicate the synthesis but also make direct GC or HPLC analysis unfeasible. Assessment of the optical purity of monoacylglycerols has, to date, relied almost exclusively on specific rotation data, which are small in value and thus insensitive to impurities. Now, a simple means to "magnify" the small specific rotations has been found, along with practical methods for the measurement of both 1,2-and 1,3-acyl migrations, which offer a convenient and straightforward alternative to Mori's NMR analysis of Mosher esters. With the aid of these methods, a range of conditions for deacetonide removal were examined en route to the synthesis of two natural monoacylglycerols. Refined hydrolysis conditions, along with useful knowledge about the solubility and reactivity of substrates with an ultra long alkyl chain are also presented. Copyright
Synthesis of modified peptidoglycan precursor analogues for the inhibition of glycosyltransferase
Dumbre, Shrinivas,Derouaux, Adeline,Lescrinier, Eveline,Piette, Andre,Joris, Bernard,Terrak, Mohammed,Herdewijn, Piet
supporting information; experimental part, p. 9343 - 9351 (2012/07/14)
The peptidoglycan glycosyltransferases (GTs) are essential enzymes that catalyze the polymerization of glycan chains of the bacterial cell wall from lipid II and thus constitute a validated antibacterial target. Their enzymatic cavity is composed of a donor site for the growing glycan chain (where the inhibitor moenomycin binds) and an acceptor site for lipid II substrate. In order to find lead inhibitors able to fill this large active site, we have synthesized a series of substrate analogues of lipid I and lipid II with variations in the lipid, the pyrophosphate, and the peptide moieties and evaluated their biological effect on the GT activity of E. coli PBP1b and their antibacterial potential. We found several compounds able to inhibit the GT activity in vitro and cause growth defect in Bacillus subtilis. The more active was C16-phosphoglycerate-MurNAc-(l-Ala-d-Glu)-GlcNAc, which also showed antibacterial activity. These molecules are promising leads for the design of new antibacterial GT inhibitors.
