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Search for "amide" in Full Text gives 859 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
One-step route to tricyclic fused 1,2,3,4-tetrahydroisoquinoline systems via the Castagnoli–Cushman protocol
Beilstein J. Org. Chem. 2020, 16, 1456–1464, doi:10.3762/bjoc.16.121
- should be noted that due to the planar amide fragment the interconversion of the different conformers could be largely suppressed. The X-ray analysis of the above-mentioned (−)-trans-22 [35] and trans-1-ethylbenzo[a]quinolizin-4-ones [40] showed a distortion of the B and C rings, while the substituent at
The McKenna reaction – avoiding side reactions in phosphonate deprotection
Beilstein J. Org. Chem. 2020, 16, 1436–1446, doi:10.3762/bjoc.16.119
- problem. Section 1: Formation of oxazoles from propargylamides One of the most intriguing side reactions was observed when compounds comprising a propargyl amide group were treated with BTMS. Besides the products of addition of HBr, we observed the formation of oxazole. In order to study this process, we
- out overnight [26][27]. However, during the first step of the McKenna reaction, alkyl bromide is formed (Scheme 1) representing an alkylating agent, which upon prolonged reaction time, may lead to side product formation. In order to study this process, we chose phosphonate analogs 9a–d and acryl amide
An overview on disulfide-catalyzed and -cocatalyzed photoreactions
Beilstein J. Org. Chem. 2020, 16, 1418–1435, doi:10.3762/bjoc.16.118
- engage with the peptide backbone via an H-bonding interaction, and in order to achieve a high enantioselectivity, the amide functionalization of the peptide at the 4-proline position is essential. Amide-substituted vinylcyclopropanes have a relatively good H-bond-donating ability, so they are more
- by homolysis of diphenyl disulfide under visible light triggers the HAT-initialized pathway 1. The hydrogen abstraction from the Hantzsch ester 44 by the thiyl radical 43 gives the ester radical 45. Then, the subsequent SET from the Hantzsch ester radical 45 to the acetamide 46 forms the amide
Recent synthesis of thietanes
Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116
- cleavage and aromatization to give substituted pyridines 255 [75] (Scheme 49). In 1989, Kanaoka and co-workers further studied the photo [2 + 2] cycloadditions of thiobarbiturates 256–258, whose skeletons consisted of a combination of a thioamide and an amide or a thioamide (two-imides system), and olefins
Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides
Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115
- chloride–lithium chloride complex (iPrMgCl⋅LiCl), known as turbo Grignard [45]. In addition to being widely cited, turbo Grignard is a popular discovery-scale tool in the pharmaceutical industry [32] and has shown an excellent selectivity on a large scale [46]. Halomagnesium amide LiCl adducts, e.g., the
- . Challenges: Gas formation from amine deprotonation, residence time optimization due to variations in the amine and amide properties. System setup: The same flow system was used as for the generation of turbo Grignard reagents (Figure S2, Supporting Information File 1). For TMPH, a coil (V = 10 mL, ID = 0.03
- flowing iPrCl/amine, 1:1 dissolved in THF/toluene, 1:1 at a 0.5 mL/min flow rate and 80 °C. Toluene was required to solubilize the magnesium amide species. During the process, propane was generated, but no overpressure was observed. The flammable gas was released after the BPR, together with the R2NMgCl
Synthesis, antiinflammatory activity, and molecular docking studies of bisphosphonic esters as potential MMP-8 and MMP-9 inhibitors
Beilstein J. Org. Chem. 2020, 16, 1277–1287, doi:10.3762/bjoc.16.108
- antiinflammatory activity of these compounds has been gaining attention. In our previous work, we synthesized and in vivo evaluated the bisphosphonic esters 1 and 2, finding a moderate edema inhibition upon oral and topical administration on BALB/c mice. Thus, in this work, the bioisosteric replacement of an amide
- molecular modification of the derivatives 1 and 2 through the bioisosteric replacement [20] of the amide functional group by an aliphatic or aromatic ester. The potential antiinflammatory activity of the new bisphosphonates was predicted using the Prediction of Activity Spectra for Substances (PASSOnline
- ) of 1.86 Å (or a 2.60 Å O–N distance) and an energy of −1.51 kcal/mol. The second interaction, stronger than the first one, was observed from an oxygen atom (P=O) of the phosphonate unit to an amide hydrogen atom located between Ile159 and Leu160. It possesses an energy of −2.5 kcal/mol and a 1.86 Å
Oxime radicals: generation, properties and application in organic synthesis
Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107
- relatively low yield of product 138f was explained by the steric effect of the ortho-methyl substituent in amide 137. In most cases, N-aryl-N-methylmethacrylamides were used for this cyclization to obtain oxindoles (products 138a–g) except for one example where a homologous amide was used to obtain six
Activated carbon as catalyst support: precursors, preparation, modification and characterization
Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104
- ammonia due to the evolution of NH3 and HCN. Depending on the modification temperature, nitrogen is incorporated mainly to aromatic rings at higher temperatures, while less temperature-stable amide-like functionalities were formed at lower temperatures [129]. Composition of activated carbon Elemental
A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium
Beilstein J. Org. Chem. 2020, 16, 1100–1110, doi:10.3762/bjoc.16.97
- mixture, which was then extracted with EtOAc. After removing the solvent, the residue was purified on a silica gel thin-layer plate (Kieselgel 60F254; Merck Co.) developed by a mixture of CHCl3/MeOH 1:1. Extraction of the collected fraction with MeOH and evaporation gave (R)-PGME amide 5a (0.6 mg): 1H NMR
Fluorinated phenylalanines: synthesis and pharmaceutical applications
Beilstein J. Org. Chem. 2020, 16, 1022–1050, doi:10.3762/bjoc.16.91
- were hydrogenated either under homogeneous or heterogeneous conditions followed by deprotection of both the amide and the ester moieties to give the racemic fluorinated phenylalanines 53a,b, or m-fluorophenylalanine (81) with good yields [57] (Scheme 19). 1.8. Coupling of N
- group for the reaction providing the desired product with 57% yield. Also, methyl and ethyl esters as C-terminal protecting groups in combination with phthalimino as the N-terminal protecting group, were both successfully explored. However, when the trifluoroacetyl amide was used as a substrate the
Copper-catalysed alkylation of heterocyclic acceptors with organometallic reagents
Beilstein J. Org. Chem. 2020, 16, 1006–1021, doi:10.3762/bjoc.16.90
- , it was shown that upon the treatment with an amine, this enolate produced the final chiral amide product with a good yield (82%) and ee (96%). While the methodology for the ACAs of Grignard reagents to chromones and coumarins has been established successfully, quinolones remained challenging
- quinolone scope revealed that substrates bearing Me, Br, CF3, ether, amide, and ester substituents, respectively, were also tolerated successfully. In addition, the catalytic system was applied to the synthesis of the natural product (+)-angustureine with an excellent outcome (92% yield, 97% ee) (Scheme 6A
Suzuki–Miyaura cross coupling is not an informative reaction to demonstrate the performance of new solvents
Beilstein J. Org. Chem. 2020, 16, 1001–1005, doi:10.3762/bjoc.16.89
- applicable) of Suzuki–Miyaura cross couplings [8]. Despite this, the reaction is generally tolerant of a wide range of solvents (often an ether or amide solvent is used, and water is a common co-solvent). This calls into question the benefits of using Suzuki–Miyaura cross coupling as a test of new solvents
Pd-catalyzed asymmetric Suzuki–Miyaura coupling reactions for the synthesis of chiral biaryl compounds with a large steric substituent at the 2-position
Beilstein J. Org. Chem. 2020, 16, 966–973, doi:10.3762/bjoc.16.85
- 3d). The yield and ee value of an oxazolidinone amide were slightly lower than those of tetrahydropyrrolamide (3e, 3f). Various aromatic substituted amides were investigated. The results show that electron-rich or electron-deficient substituents on the phenyl ring have no significant influence on the
- decreased with the increase of the substituent on the boronic acid. When a methyl or methoxy group were present at the ortho-position of 1-naphthaleneboronic acid, the reactions were hard to move on even at 70 °C. By replacing the 3-methyl group of the amide with a 3-methoxy or a 3-benzyloxy group, the
- hindrance of the 4-substituted boronic acid. Next, in order to confirm our speculation, the amide group of the aryl bromide was replaced with other functional groups, as shown in Scheme 2. When the amide group was changed into an amine, coupling product 5a was obtained quantitatively but without any
Aldehydes as powerful initiators for photochemical transformations
Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76
- , to the amide 83, as shown in Scheme 22. The low yield of the amide formation was attributed mainly to a concurrent imine formation, which was catalyzed by benzoic acid formed as a result of benzaldehyde (8) oxidation during the photoreaction. There was also a competition between two bimolecular
- aliphatic moieties, amide bonds, triple bonds, or ether moieties afforded the desired products in moderate to good yield (156, 158, 162a–e). α,α-Disubstituted aldehydes also afforded the products in good yield and moderate to good selectivity (162f–k). Benzyl diesters and aliphatic diesters were compatible
Efficient synthesis of piperazinyl amides of 18β-glycyrrhetinic acid
Beilstein J. Org. Chem. 2020, 16, 798–808, doi:10.3762/bjoc.16.73
- conditions. Furthermore, the reasons for the appearance of byproducts were elucidated. Crystallographic data of a selected piperazinyl amide is reported. Keywords: 18β-glycyrrhetinic acid; piperazinyl amides; synthesis; Introduction Glycyrrhizin was the major bioactive component in Glycyrrhiza uralensis
- . Besides, the C-30 carboxyl group is often esterified or amidated in order to enhance the antitumor or other efficacy of 18β-glycyrrhetinic acid derivatives [11]. A novel piperazinyl amide b exhibits the optimal inhibitory activity against MCF-7 and can be further developed as a potent VEGFR2 and antitumor
- agent [12]. Piperazinyl amide fragments have the ability to form several hydrogen bonds, modulate the acid–base equilibrium constant and change the octanol–water partition coefficient [13]. They are considered as the basic motif for designing many biologically active molecules [14][15]. Some piperazinyl
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 use of several coupling reagents in the synthesis of amide bonds. Results and Discussion Our goal was to increase the efficiency of the synthesis of α-fluorinated β-aminophosphonate dipeptide analogues 15. In the first stage, we optimized Pudovik's reaction (Scheme 1) [32]. In our previous
Combining enyne metathesis with long-established organic transformations: a powerful strategy for the sustainable synthesis of bioactive molecules
Beilstein J. Org. Chem. 2020, 16, 738–755, doi:10.3762/bjoc.16.68
- dienic relay unit, were prepared from Weinreb amide by an asymmetric pathway, were reacted with either the Grubbs second-generation catalyst, the Hoveyda–Grubbs second-generation catalyst, or the Zhan catalyst, the latter giving under the optimized conditions the highest yield of the expected
- of cyclopentene-1,4-diol that was obtained by the enzymatic desymmetrization of the corresponding diacetate, an enyne metathesis precursor was accessed by a Mitsunobu-type coupling reaction with propargylic amide. The ring-rearrangement metathesis (RRM) of this enyne precursor was carried out using
- (+)-virosaine B (19) from Weinreb amide by enyne metathesis as the key step. Access to virgidivarine (20) and virgiboidine (21) by an enyne metathesis route. Enyne metathesis approach to (−)-zenkequinone B (22). Access to C-aryl glycoside 23 by an intermolecular enyne metathesis/Diels–Alder cycloaddition
Towards the total synthesis of chondrochloren A: synthesis of the (Z)-enamide fragment
Beilstein J. Org. Chem. 2020, 16, 670–673, doi:10.3762/bjoc.16.64
- Hannover, Germany 10.3762/bjoc.16.64 Abstract The stereoselective synthesis of the (Z)-enamide fragment of chondrochloren (1) is described. A Buchwald-type coupling between amide 3 and (Z)-bromide 4 was used to generate the required fragment. The employed amide 3 comprising three chiral centers was
- of the molecule was elucidated by a combination of NMR, UV and IR spectroscopy and molecular dynamics calculations (MD, MM2) [12]. However, its (Z)-enamide motif and the polyoxygenated middle segment are synthetically challenging. Results and Discussion Synthesis of amide 3 Here we report our
- investigations on the construction of the segments 3 and 4 as well as our results on the cross coupling between both fragments. Our retrosynthetic approach (Figure 1) divides chondrochloren A (1) into three fragments of similar complexity: amide 2, (Z)-bromide 4 and amide 3. For the coupling of amide 3 and (Z
Microwave-assisted efficient and facile synthesis of tetramic acid derivatives via a one-pot post-Ugi cascade reaction
Beilstein J. Org. Chem. 2020, 16, 663–669, doi:10.3762/bjoc.16.63
- ][39]. Spatz’ team reported a novel two-step synthetic procedure for the preparation of substituted tetramic acid derivatives via an Ugi/Dieckmann reaction [40]. A leaving amide that was derived from the isonitrile, provided the tetramic acid core under strong inorganic basic conditions. In this method
- , a convertible isonitrile promoted the cyclization, but restricted the scope of structural diversity. For this reason, it is desirable to replace the amide with a better leaving group, an ester group, which will undergo the Dieckmann reaction more effectively to form a five-membered ring. It is worth
Copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters with chiral phenol–carbene ligands
Beilstein J. Org. Chem. 2020, 16, 537–543, doi:10.3762/bjoc.16.50
- affected the stereoselectivities: Lower enantioselectivities were observed with benzyl ester 2g (Table 2, entry 8, >99% yield, 70% ee) and isopropyl ester 2h (Table 2, entry 9, >99% yield, 83% ee). In addition to the α,β-unsaturated esters, an α,β-unsaturated Weinreb amide 1i afforded the corresponding
Exploring the scope of DBU-promoted amidations of 7-methoxycarbonylpterin
Beilstein J. Org. Chem. 2020, 16, 509–514, doi:10.3762/bjoc.16.46
- relevant pteridine derivatives. Reactions which expedite the development of new pterins are thus of great importance. Through a dual role of diazabicycloundecene (DBU), 7-carboxymethylpterin is converted to the soluble DBU salt, with additional DBU promoting an ester-to-amide transformation. We have
- modifications to the pteridine core which disrupt the hydrogen-bond assembly, such as benzylation of the lactam oxygen or conversion of the exocyclic amine to the pivalic amide [12][13]. The installation and subsequent removal of these groups naturally affects the overall yield and time necessary to generate
- bypassed the problematic insolubility and assisted in derivatization [14][15][16]. In addition to this improvement in solubility, we can further take advantage of a mechanistic role of DBU, as it catalyzes the ester-to-amide transformation, allowing for 7-methoxycarbonylpterin (7-CMP, 1) to smoothly
Controlling alkyne reactivity by means of a copper-catalyzed radical reaction system for the synthesis of functionalized quaternary carbons
Beilstein J. Org. Chem. 2020, 16, 502–508, doi:10.3762/bjoc.16.45
- reaction of compound 4 if it did not possess an alkyl substituent on the nitrogen atom of the amide bond. Conclusion In summary, we have developed two types of tandem reactions catalyzed by a copper salt. The reaction of 2-bromocarbonyl compounds and aryl-substituted alkynes underwent alkyl radical
Aerobic synthesis of N-sulfonylamidines mediated by N-heterocyclic carbene copper(I) catalysts
Beilstein J. Org. Chem. 2020, 16, 482–491, doi:10.3762/bjoc.16.43
- : catalysis; copper; copper catalysis; N-heterocyclic carbene; solvent-free; sulfonylamidines; Introduction Amide derivatives represent a ubiquitous molecular construct in chemistry [1][2][3]. This structural motif favours rearrangements that lead to high reactivity and associated bioactivity [4][5]. Indeed
Architecture and synthesis of P,N-heterocyclic phosphine ligands
Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35
- (diphenylphosphino)-1,1'-binaphthyl (BINAP) with a greater π-density and sterically demanding groups, have been extensively used in catalytic reactions [94]. Wang et al. [95] reported a copper-catalyzed phosphorylation in the synthesis of an oxazolylindolylphosphine as shown in Scheme 18. The intermediate amide 97
- methanesulfonyl chloride mediated cyclization of amide 97 and reaction with methyl iodide or methoxymethyl chloride afforded the N-substituted indole derivatives 99 (R = Me, MOM). The desired phosphinylated compounds 102 were obtained via three routes: The dicyclohexylphosphine derivatives 102a and b were only
p-Pyridinyl oxime carbamates: synthesis, DNA binding, DNA photocleaving activity and theoretical photodegradation studies
Beilstein J. Org. Chem. 2020, 16, 337–350, doi:10.3762/bjoc.16.33
- cm−1, characteristic of the amide moiety. This low carbonyl absorption probably indicates an intramolecular hydrogen bonding between NH2 and the oxime oxygen, which further verifies the Z-conformation of the amidoxime derivatives. The hydroxylimino structure is verified in 1H NMR spectra from the
- group appears around 3200–3300 cm−1 and the carbonyl absorption had the characteristics of an ester, rather than an amide, at 1720 (benzyl derivative, 15) and 1750–1786 cm−1 for compounds with the NH adjusted on the aromatic ring. In the 1H NMR spectra the NH of the aryl derivatives 16–20 appeared at
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