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Search for "analogue" in Full Text gives 611 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Polarity effects in 4-fluoro- and 4-(trifluoromethyl)prolines
Beilstein J. Org. Chem. 2020, 16, 1837–1852, doi:10.3762/bjoc.16.151
- chemically inert under most biologically relevant conditions. The presence of these groups adjacent to the proline structure helps to modulate the conformational landscape of the parent amino acid, and this effectively alters the folding of the peptide chain when an analogue is included in it as a residue
- complex structures: peptides and proteins. Results and Discussion Model compounds The study was originally set up following an assumption that a peptide containing a proline analogue would form a system of three dipoles. The peptide bond itself creates a strong dipole, with a direction that roughly aligns
- fluorine-containing substituent adds a new dipole to the system. A C–F dipole is estimated as 1.9 D, whereas a CF3-group dipole is about 2.4 D [60]. Thus, a proline analogue that contains these substituents would form a system of three mutually interacting dipoles (Figure 3). To mimic this situation, a
Pauson–Khand reaction of fluorinated compounds
Beilstein J. Org. Chem. 2020, 16, 1662–1682, doi:10.3762/bjoc.16.138
- steric or electronic nature of the other substituent. These results contrast with those obtained for non-fluorinated analogue (ethyl 2-butynoate) for which the expected regioisomer 60 was formed, bearing the methyl group at the α-position and the electron-withdrawing ester group in the β-position. These
Heterogeneous photocatalysis in flow chemical reactors
Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125
Recent synthesis of thietanes
Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116
- as inhibitor of kinases, insecticides, and acaricides, its sulfur analogue, 6-amino-2-thiaspiro[3,3]heptane (28) was prepared from the cheap starting material 2,2-bis(bromomethyl)propane-1,3-diol (11). Compound 11 was converted into 3-(tert-butoxycarbonyl)-1,1-bis(hydroxymethyl)aminocyclobutane (25
- ). Following similar protocols, (S,S)-2,3-bis(benzoyloxymethyl)thietane (34) was synthesized from diethyl L-tartrate (32), which was further converted into thietanocin A (35), a sulfur analogue of oxetanocin A [39] (Scheme 7). The double displacement cyclic thioetherification strategy was also utilized for the
- succeeded in the synthesis of a 4’,4’-spirothietane-2’,N3-cycloadenosine 46 as a highly constrained analogue of 5’-deoxy-5’-methylthioadenosine. They first prepared tritosylate derivative 44 from D-glucose which was treated with KSAc to give the spirothietane derivative 45. The latter compound was further
Fluorinated phenylalanines: synthesis and pharmaceutical applications
Beilstein J. Org. Chem. 2020, 16, 1022–1050, doi:10.3762/bjoc.16.91
- , geometry, conformation, reactivity, and moreover the bioavailability of the analogue [1]. Fluorinated amino acids (FAAs) have considerable industrial and pharmaceutical potential [2]. Also, they have played an important role as enzyme inhibitors as well as therapeutic agents [3][4]. Moreover, they modulate
- analogue of sitagliptin which was developed for the same application [109][117], but compound 184 appears to have an improved activity [118]. Retagliptin showed efficacy in clinical trials and is now entering phase III studies. (R)-2,4,5-Trifluorophenylalanine 38b is used as a building block in the
Copper catalysis with redox-active ligands
Beilstein J. Org. Chem. 2020, 16, 858–870, doi:10.3762/bjoc.16.77
- copper complex 22 in as fast as two minutes, and therefore, it exhibits a strong increase in reactivity when compared to its unstrained analogue [40]. This example of a bioinspired small-molecule synthetic system combines two reactivity-enhancing features from metalloenzymes: entasis and redox cofactors
Efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates
Beilstein J. Org. Chem. 2020, 16, 756–762, doi:10.3762/bjoc.16.69
- of the product formation (88%) was observed, however, the reaction still required a long reation time. Finally, COMU [45] as a coupling reagent was applied. The model reaction took place with a yield of 92% after just two hours. COMU allowed to obtain the dipeptide analogue 15a not only with an
- ether under an argon atmosphere. The mixture was left overnight in a freezer. The next day, the precipitate was filtered off to give a white solid. Procedure for the synthesis of dipeptide analogues 15 DCC/HOBt conditions: The analogue 15a was prepared in a similar manner as described in [35]. To a
Design and synthesis of diazine-based panobinostat analogues for HDAC8 inhibition
Beilstein J. Org. Chem. 2020, 16, 628–637, doi:10.3762/bjoc.16.59
- building blocks for TOI1, TOI2, TOI3-rev and TOI4 were selected based on their ability to tether the indole amine and the zinc binding group in a para-relationship to each other. Initial efforts focused on synthesizing analogue TOI1 (Scheme 1). Acid 1 was converted to the corresponding methyl ester 5 via
- % and 51% yield, respectively, after C18 silica gel purification procedure using a methanol/water (1:1) solvent system. Finally, we focused our efforts towards the synthesis of the last analogue TOI4. From the above observations, we hypothesize that successful synthesis of TOI4 would rely on generating
Synthesis of triphenylene-fused phosphole oxides via C–H functionalizations
Beilstein J. Org. Chem. 2020, 16, 524–529, doi:10.3762/bjoc.16.48
- , FeCl3, Cu(OTf)2, and AlCl3 failed to promote the cyclization of 7a to 8a. The PIFA/BF3·OEt2 system also promoted the Scholl reaction of terphenyl 7b bearing a methylenedioxy moiety with a comparable efficiency to afford 8b in 56% yield. Compound 8c, a naphthylene-linked analogue of 8a, also underwent
Rapid, two-pot procedure for the synthesis of dihydropyridinones; total synthesis of aza-goniothalamin
Beilstein J. Org. Chem. 2020, 16, 135–139, doi:10.3762/bjoc.16.15
- )-(+)-goniothalamin 2 and acylated aza-goniothalamin analogue 3 [14][15][16][17][18]. Extension of the two-pot methodology to include a variety of different aldehyde starting materials. One pot synthesis of benzyl carbamate 4 reported by Veenstra and co-workers [19]. Formation of diene 5 in 66% through a one pot
Potent hemithioindigo-based antimitotics photocontrol the microtubule cytoskeleton in cellulo
Beilstein J. Org. Chem. 2020, 16, 125–134, doi:10.3762/bjoc.16.14
- colchicine or its analogue combretastatin A-4 and was bioactive, while the other isomer clashed with their SAR and was less active [18]. That approach of directly embedding a photoswitch motif inside the pharmacophore seemed to be more promising for photopharmacology than the synthetically more
- ) delivered results equivalent to dark conditions (exclusively Z-configuration), to which 450 nm (lit conditions, ca. 70% E-configuration) gave the greatest difference in antiproliferative potencies. We began our studies with HITub-1. This is a HTI analogue of indanocine in which the indanocine amino function
Light-controllable dithienylethene-modified cyclic peptides: photoswitching the in vivo toxicity in zebrafish embryos
Beilstein J. Org. Chem. 2020, 16, 39–49, doi:10.3762/bjoc.16.6
- photoswitchable analogue 2 in an allograft mouse model, the first in vivo photopharmacology application for a DAE-derived peptide as an anticancer agent has been demonstrated [29]. In order to optimize 2, we have recently performed a structure–activity relationship (SAR) study using a library of photoswitchable
Microwave-assisted synthesis of 2-substituted 4,5,6,7-tetrahydro-1,3-thiazepines from 4-aminobutanol
Beilstein J. Org. Chem. 2020, 16, 32–38, doi:10.3762/bjoc.16.5
- prepared by a double displacement reaction between 2,6-dichlorothiobenzamide and 1,4-butylene dibromide [29]. In 1970, Mente prepared a dehydro analogue, namely 2-(4-chlorophenyl)-4,7-dihydro-1,3-thiazepine, via thermolysis of N-(4-chlorothiobenzoyl)-2-vinylaziridine [30]. No yields were reported for these
Starazo triple switches – synthesis of unsymmetrical 1,3,5-tris(arylazo)benzenes
Beilstein J. Org. Chem. 2020, 16, 22–31, doi:10.3762/bjoc.16.4
- using an aqueous ammonium sulfide solution to furnish aniline 6 in 65% yield [20]. After oxidation of 6 to its nitroso analogue 7 [21], a Baeyer–Mills reaction with aniline yielded the targeted azobenzene building block 8 in 87% yield (i.e., 53% yield over four steps). After the successful synthesis of
Chemical synthesis of tripeptide thioesters for the biotechnological incorporation into the myxobacterial secondary metabolite argyrin via mutasynthesis
Beilstein J. Org. Chem. 2019, 15, 2922–2929, doi:10.3762/bjoc.15.286
- has been observed in many cases that exogenous substrates can be incorporated by bacteria into biosynthesis cascades of natural products. The use of substrates which lead to nonnatural derivatives of the natural product coined the field of mutasynthesis, e.g., siderophore analogue biosynthesis by P
Synthesis and optoelectronic properties of benzoquinone-based donor–acceptor compounds
Beilstein J. Org. Chem. 2019, 15, 2914–2921, doi:10.3762/bjoc.15.285
- compare the monofunctionalized BQ 2 with a difunctionalized analogue, 5 was also prepared for our investigation. As 2,5-difunctionalized BQs with electron-donating groups are not accessible via the Pd(II)-catalyzed direct C–H functionalization method utilized in Scheme 2 (since the selectivity for
Influence of the cis/trans configuration on the supramolecular aggregation of aryltriazoles
Beilstein J. Org. Chem. 2019, 15, 2881–2888, doi:10.3762/bjoc.15.282
- (Scheme 2) showed supramolecular features, i.e., their DMSO solutions prepared for NMR analyses spontaneously transformed into gels inside the NMR tubes. Three cis-/trans-configured pairs of compounds were chosen for a gelation ability study. Thus, analogue pairs 8f/7f (Scheme 2), 10/9 (Scheme 3), and 14
An improved, scalable synthesis of Notum inhibitor LP-922056 using 1-chloro-1,2-benziodoxol-3-one as a superior electrophilic chlorinating agent
Beilstein J. Org. Chem. 2019, 15, 2790–2797, doi:10.3762/bjoc.15.271
- penetration is an essential requirement of the compound but would be an ideal peripherally restricted control. These data will contribute to the understanding of drug levels of 1 to overlay with appropriate in vivo efficacy endpoints, i.e., the PK-PD relationship. The identification of a suitable analogue of
- tool by capping off the acid as an amide. Although significant Notum inhibition activity could be achieved, none of these amides demonstrated the required combination of metabolic stability along with cell permeability without evidence of P-gp mediated efflux. The identification of a suitable analogue
A combinatorial approach to improving the performance of azoarene photoswitches
Beilstein J. Org. Chem. 2019, 15, 2753–2764, doi:10.3762/bjoc.15.266
- the Z-isomer-enriched PSS. Theoretical π–π* band separations for the E-isomers of 4pzMe-F2 and 4pzMe-Cl2 (Table 2) match very closely with the experimental data (Table 3), with the exception of the methoxy 4pzMe-OMe2 analogue. A large conformational space is expected for the twisted 4pzMe-OMe2 (vide
Nanangenines: drimane sesquiterpenoids as the dominant metabolite cohort of a novel Australian fungus, Aspergillus nanangensis
Beilstein J. Org. Chem. 2019, 15, 2631–2643, doi:10.3762/bjoc.15.256
- significant differences being the absence of the 6-OH proton, the presence of additional signals for a C6 acyl chain, and significant deshielding of H-6 from δH 4.30 to 5.47 ppm. Therefore, the structure of 2 was assigned as the 6-O-hexanoyl analogue of 1, as shown in Figure 1. Compound 2 was previously
- File 1) with those for 2 revealed the only significant differences to be the absence of the H-1 and 1-OH protons and the presence of an additional methylene group (H2-1). Therefore, the structure of 4 was assigned to be the 1-deoxy analogue of 2, as shown in Figure 1. Compound 4 was previously reported
- , while HMBC correlations from H-7 to C-12 and from H3-12 to C-9 positioned the methyl on C-8. Therefore, the structure of 8 was assigned as the seco analogue of 2, as shown in Figure 1. The absolute configuration of 8 was assigned to be the same as 2 based on their similar NMR data and optical rotations
AgNTf2-catalyzed formal [3 + 2] cycloaddition of ynamides with unprotected isoxazol-5-amines: efficient access to functionalized 5-amino-1H-pyrrole-3-carboxamide derivatives
Beilstein J. Org. Chem. 2019, 15, 2623–2630, doi:10.3762/bjoc.15.255
- clinical trials against colon cancer, gall bladder cancer and acute myelogenous leukemia in humans [40] and its 2-aza analogue 3 is also active against human cytomegalovirus (HCMV) and herpes simplex virus type 1 (HSV-1) [41]. To the best of our knowledge, this case of α-imino silver-carbene is not yet
Synthesis of novel sulfide-based cyclic peptidomimetic analogues to solonamides
Beilstein J. Org. Chem. 2019, 15, 2544–2551, doi:10.3762/bjoc.15.247
- blood cells (see Supporting Information File 1, assay 3) [43]. Analogue 9e showed better capacity to inhibit the hemolysis than 9g at the same concentration (Figure 3). At concentrations of 10 µM and 200 µM of 9e, the hemolysis production by S. aureus was inhibited by 63% and 84%, respectively. Also, a
Formation of alkyne-bridged ferrocenophanes using ring-closing alkyne metathesis on 1,1’-diacetylenic ferrocenes
Beilstein J. Org. Chem. 2019, 15, 2534–2543, doi:10.3762/bjoc.15.246
- analogue of the formula [Fe{C5H4COO(CH2)3 C≡}2]2 in a ratio of approximately 4:1. Related NMR spectra can be found in Supporting Information File 1 (Figures S9 and S10). Separation of the monomer 2b could be achieved with column chromatography on silica gel with a yield of 53%. The ring-closed dimer
α,ß-Didehydrosuberoylanilide hydroxamic acid (DDSAHA) as precursor and possible analogue of the anticancer drug SAHA
Beilstein J. Org. Chem. 2019, 15, 2524–2533, doi:10.3762/bjoc.15.245
- induce apoptosis, and to induce generation of ROS. Compounds 11b and 11f were arbitrarily chosen, while the shorter chain analogue 11g was selected to compare the effect of chain length, if any. Direct comparison with SAHA was made to quantify the effects shown by these three compounds in each of the
- clearly the truncated analogue 11g is less effective. Loss of cell viability by LDH assay LDH assays quantitatively measures lactate dehydrogenase (LDH) released into the media from damaged cells as a biomarker for cellular cytotoxicity [35][36]. Hence, to further characterize compound-induced HeLa cell
A toolbox of molecular photoswitches to modulate the CXCR3 chemokine receptor with light
Beilstein J. Org. Chem. 2019, 15, 2509–2523, doi:10.3762/bjoc.15.244
- azobenzene analogue 2a, we explored the substitution pattern of the outer aromatic ring with chlorine atoms in the ortho, meta and para-position (compounds 2b–d, respectively) to also assess the possibility of agonism provided by a halogen bond. Compound 2e, which contains a bromine atom in the ortho
- unit Aiming to improve the position and directionality of the halogen atom, we next designed a subseries with the azo group at the meta-position of the central ring (scaffold 3) instead of at the para-position as in 2a–e. The analogue without halogen substitution (3a) as well as Cl/Br analogues
- oxidation of methyl 3-aminobenzoate (17a) using Oxone® to obtain a crude nitroso product 18a, which was used in a Mills reaction with an iodoaniline (19a–c) at 100 °C to obtain azobenzenes 20g,h in high yields and ortho-analogue 20f in a decreased yield presumably due to steric hindrance. The methyl ester
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