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1.
Dr. Marie Betou Dr. Louise Male Prof. Jonathan W. Steed Dr. Richard S. Grainger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(21):6505-6517
In an approach to the biologically important 6‐azabicyclo[3.2.1]octane ring system, the scope of the tandem 4‐exo‐trig carbamoyl radical cyclization—dithiocarbamate group transfer reaction to ring‐fused β‐lactams is evaluated. β‐Lactams fused to five‐, six‐, and seven‐membered rings are prepared in good to excellent yield, and with moderate to complete control at the newly formed dithiocarbamate stereocentre. No cyclization is observed with an additional methyl substituent on the terminus of the double bond. Elimination of the dithiocarbamate group gives α,β‐ or β,γ‐unsaturated lactams depending on both the methodology employed (base‐mediated or thermal) and the nature of the carbocycle fused to the β‐lactam. Fused β‐lactam diols, obtained from catalytic OsO4‐mediated dihydroxylation of α,β‐unsaturated β‐lactams, undergo semipinacol rearrangement via the corresponding cyclic sulfite or phosphorane to give keto‐bridged bicyclic amides by exclusive N‐acyl group migration. A monocyclic β‐lactam diol undergoes Appel reaction at a primary alcohol in preference to semipinacol rearrangement. Preliminary investigations into the chemo‐ and stereoselective manipulation of the two carbonyl groups present in a representative 7,8‐dioxo‐6‐azabicyclo[3.2.1]octane rearrangement product are also reported. 相似文献
2.
Gold‐Catalyzed Cyclization Leads to a Bridged Tetracyclic Indolenine that Represses β‐Lactam Resistance
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Dr. Wenqing Xu Dr. Wei Wang Prof. Dr. Xiang Wang 《Angewandte Chemie (International ed. in English)》2015,54(33):9546-9549
A gold‐catalyzed desilylative cyclization was developed for facile synthesis of bridged tetracyclic indolenines, a common motif in many natural indole alkaloids. An antimicrobial screen of the cyclization products identified one compound which selectively potentiates β‐lactam antibiotics in methicillin‐resistant S. aureus (MRSA), and re‐sensitizes a variety of MRSA strains to β‐lactams. 相似文献
3.
Mehmet Kabak Yal
in Elerman Vildan Güner Tahsin Nuri Durlu 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(5):e207-e208
In the title compound, C35H26ClNO, the four‐membered β‐lactam ring is essentially planar, with a maximum deviation of 0.012 (1) Å for the N atom. The C—C bond lengths in the β‐lactam ring are 1.591 (2) and 1.549 (2) Å. The two phenyl rings attached to the β‐lactam ring are nearly perpendicular to each other [83.2 (1)°]. 相似文献
4.
Palladium‐Catalyzed Oxidative Carbonylation of N‐Allylamines for the Synthesis of β‐Lactams
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Wu Li Dr. Chao Liu Prof. Heng Zhang Keyin Ye Guanghui Zhang Wangzheng Zhang Zhengli Duan Prof. Shuli You Prof. Aiwen Lei 《Angewandte Chemie (International ed. in English)》2014,53(9):2443-2446
β‐Lactam scaffolds are considered to be ideal building blocks for the synthesis of nitrogen‐containing compounds. A new palladium‐catalyzed oxidative carbonylation of N‐allylamines for the synthesis of α‐methylene‐β‐lactams is reported. DFT calculations suggest that the formation of β‐lactams via a four‐membered‐ring transition state is favorable. 相似文献
5.
《中国化学》2018,36(7):612-618
Chiral β‐lactams and cyclobutanones are present in numerous natural and pharmaceutical products. The stereoselective construction of chiral four‐membered cyclic compounds is an ongoing challenge for the chemical community. Herein, we report a highly stereocontrolled construction of four‐membered ring (mini‐sized) β‐lactams and cyclobutanones via an Ir/ In‐BiphPHOX ‐catalyzed asymmetric hydrogenation, providing the corresponding optically active four‐membered ring carbonyl products bearing an α‐chiral carbon center with excellent yields (up to 99%) and enantioselectivities (up to 98%) under mild reaction conditions (1.0—2.5 bar H2 for 1.0—10 h). The reaction presents wide substrate scope. Diverse transformations of the catalyzed products were also conducted to show the potential utility of this protocol. 相似文献
6.
Unsymmetric cyclic ketenes were generated from N‐acyl‐1,3‐thiazolidine‐2‐carboxylic acids 1a – c by means of Mukaiyama's reagent, and then reacted with imines 2a – c to the new, isomeric spiro‐β‐lactams 3 and 4 via [2+2] cycloaddition (Staudinger ketene–imine reaction; Scheme 1). The reactions were stereoselective (Table 1) and mainly afforded the spiro‐β‐lactams with a relative trans configuration. The spiro‐β‐lactams could be transformed into the corresponding monocyclic β‐lactams by means of thiazolidine ring opening or into substituted thiazolidines via hydrolysis of the β‐lactam ring. 相似文献
7.
Vratislav Langer Bohumil Steiner Miroslav Ko 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(4):o151-o154
In the title compounds, C12H20O6, (I), and C9H16O6, (II), the five‐membered furanose ring adopts a 4T3 conformation and the five‐membered 1,3‐dioxolane ring adopts an E3 conformation. The six‐membered 1,3‐dioxane ring in (I) adopts an almost ideal OC3 conformation. The hydrogen‐bonding patterns for these compounds differ substantially: (I) features just one intramolecular O—H...O hydrogen bond [O...O = 2.933 (3) Å], whereas (II) exhibits, apart from the corresponding intramolecular O—H...O hydrogen bond [O...O = 2.7638 (13) Å], two intermolecular bonds of this type [O...O = 2.7708 (13) and 2.7730 (12) Å]. This study illustrates both the similarity between the conformations of furanose, 1,3‐dioxolane and 1,3‐dioxane rings in analogous isopropylidene‐substituted carbohydrate structures and the only negligible influence of the presence of a 1,3‐dioxane ring on the conformations of furanose and 1,3‐dioxolane rings. In addition, in comparison with reported analogs, replacement of the –CH2OH group at the C1‐furanose position by another group can considerably affect the conformation of the 1,3‐dioxolane ring. 相似文献
8.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(14):3920-3924
Resistance to β‐lactam antibiotics mediated by metallo‐β‐lactamases (MBLs) is a growing problem. We describe the use of protein‐observe 19F‐NMR (PrOF NMR) to study the dynamics of the São Paulo MBL (SPM‐1) from β‐lactam‐resistant Pseudomonas aeruginosa . Cysteinyl variants on the α3 and L3 regions, which flank the di‐ZnII active site, were selectively 19F‐labeled using 3‐bromo‐1,1,1‐trifluoroacetone. The PrOF NMR results reveal roles for the mobile α3 and L3 regions in the binding of both inhibitors and hydrolyzed β‐lactam products to SPM‐1. These results have implications for the mechanisms and inhibition of MBLs by β‐lactams and non‐β‐lactams and illustrate the utility of PrOF NMR for efficiently analyzing metal chelation, identifying new binding modes, and studying protein binding from a mixture of equilibrating isomers. 相似文献
9.
Rodney L. Willer Robson F. Storey William L. Jarrett Damon Parrish 《Journal of heterocyclic chemistry》2012,49(3):705-709
The unusual 12‐membered ring compound, octahydro‐5H,12H‐4,11‐methano‐1H,7H‐bis[1,2,5]oxadiazolo[3,4‐d:3′,4′‐j][1,7,3,9]dioxadiazacyclododecine is obtained from the acid catalyzed reaction of 3‐amino‐4‐hydroxymethylfurazan with formaldehyde instead of the expected methylene‐bridged compound, 4,4′‐methylenebis[4,5‐dihydro‐7H‐[1,2,5]oxadiazolo[3,4‐d][1,3]oxazine]. The compound crystallizes in Tetragonal, P43212, a = 6.4141(4) Å, b = 6.4141(4) Å, c = 26.525(3) Å, α = 90°, β = 90°, γ = 90°, V = 1091.27(16) Å3, Z = 4, dcalc = 1.614 Mg/m3. 相似文献
10.
Jagadish Pabba BrianP. Rempel StephenG. Withers Andrea Vasella 《Helvetica chimica acta》2006,89(4):635-666
The known glucaro‐1,5‐lactam 8 , its diastereoisomers 9 – 11 , and the tetrahydrotetrazolopyridine‐5‐carboxylates 12 – 14 were synthesised as potential inhibitors of β‐D ‐glucuronidases and α‐L ‐iduronidases. The known 2,3‐di‐O‐benzyl‐4,6‐O‐benzylidene‐D ‐galactose ( 16 ) was transformed into the D ‐galactaro‐ and L ‐altraro‐1,5‐lactams 9 and 11 via the galactono‐1,5‐lactam 21 in twelve steps and in an overall yield of 13 and 2%, respectively. A divergent strategy, starting from the known tartaric anhydride 41 , led to the D ‐glucaro‐1,5‐lactam 8 , D ‐galactaro‐1,5‐lactam 9 , L ‐idaro‐1,5‐lactam 10 , and L ‐altraro‐1,5‐lactam 11 in ten steps and in an overall yield of 4–20%. The anhydride 41 was transformed into the L ‐threuronate 46 . Olefination of 46 to the (E)‐ or (Z)‐alkene 47 or 48 followed by reagent‐ or substrate‐controlled dihydroxylation, lactonisation, azidation, reduction, and deprotection led to the lactams 8 – 11 . The tetrazoles 12 – 14 were prepared in an overall yield of 61–81% from the lactams 54, 28 , and 67 , respectively, by treatment with Tf2O and NaN3, followed by saponification, esterification, and hydrogenolysis. The lactams 8 – 11 and 40 and the tetrazoles 12 – 14 are medium‐to‐strong inhibitors of β‐D ‐glucuronidase from bovine liver. Only the L ‐ido‐configured lactam 10 (Ki = 94 μM ) and the tetrazole 14 (Ki = 1.3 mM ) inhibit human α‐L ‐iduronidase. 相似文献
11.
Szilvia Gedey Ferenc Fülp Pirjo Vainiotalo Peter A. M. De Witte Istvían Zupk 《Journal of heterocyclic chemistry》2003,40(6):951-956
Five sets of 27‐membered combinatorial libraries of alicyclic β‐lactams were prepared via liquid‐phase Ugi 4‐center 3‐component reactions (U‐4C‐3CR) utilizing 3 different cis β‐amino acids, 3 different isonitriles and 5×3 sets of aldehydes. Through combinations of the building blocks of one of these libraries, all of the possible sublibraries were also generated. A few azetidinone derivatives were synthesized individually by parallel synthesis. 相似文献
12.
《Journal of heterocyclic chemistry》2018,55(5):1085-1091
The first synthesis of 3‐phenothiazine‐β‐lactams is herein reported. Thirteen new derivatives of β‐lactams were synthesized using various Schiff bases and (phenothiazin‐10‐yl)acetic acid, which in turn was prepared starting from phenothiazine. The sole product of the Staudinger ketene–imine [2 + 2] cycloaddition reaction is the trans‐β‐lactam. All the synthesized compounds were characterized by elemental analyses and spectral (IR, 1H‐NMR, and 13C‐NMR) data. 相似文献
13.
《Journal of heterocyclic chemistry》2017,54(2):944-951
Reaction of 5,6‐dihydro‐4H‐pyrrolo[3,2,1‐ij ]quinoline‐1,2‐dione ( 3 ) with two equivalents of cyclic 1,3‐dicarbonyl compounds under acid catalysis generates spiro[4H‐pyran‐3,3′‐oxindoles] 7 . In contrast, though base catalysis also achieves double addition, the final products 8 result from subsequent ring opening of the five‐membered lactam via intramolecular attack by enolate; these products can be converted into the spiro[4H‐pyran‐3,3′‐oxindoles] by treatment with acid. 相似文献
14.
Daniel Pellico Mar Gómez‐Gallego Prof. Pedro Ramírez‐López Dr. María José Mancheño Prof. Miguel A. Sierra Prof. M. Rosario Torres Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(28):6940-6952
The synthesis, isolation, and full characterization of different types of stable, metal‐assembled macrocyclic β‐lactams are reported. By using adequately functionalized bis‐β‐lactams with defined stereochemistry as building blocks, a series of mono‐ and bimetallic Pd and Pt macrocycles has been prepared in good to quantitative yields. These novel structures combine the β‐lactam moiety with transition‐metal fragments with cis‐square‐planar geometry and constitute a new class of metal‐assembled cavities involving molecules with biological relevance as building blocks. By combining the adequate ligands, metallic fragments, and tuning the reaction conditions, different mono‐ and bimetallic macrocyclic β‐lactam cavities can be selectively obtained. Macrocycles with Pt–ethynyl groups are suitable to form host–silver triflate guest complexes in a tweezer fashion. 相似文献
15.
Addition reactions of acid chlorides with various 2‐substituted 4,5‐dihydro‐4,4‐dimethyl‐5‐(methylsulfanyl)‐1,3‐thiazoles under basic conditions were studied. Two kinds of products were obtained from these additions, β‐lactams and non‐β‐lactam adducts. When the reaction was carried out with 4,5‐dihydro‐1,3‐thiazoles with a Ph substituent at C(2), the reaction proceeded via formal [2+2] cycloaddition and led to the correspoding β‐lactam. On the other hand, acid chlorides and 4,5‐dihydro‐1,3‐thiazoles bearing an α‐H‐atom at the C(2)‐substituent underwent C(α)‐ and/or N‐addition reactions and furnished non‐β‐lactam adducts, i.e., C(α)‐ and/or N‐acylated 1,3‐thiazolidines. The attempted transformations of sulfonyl esters of exo‐6‐hydroxy penams to endo‐6‐azido penams failed, although they were successful with mono‐β‐lactams under the same conditions. 相似文献
16.
Julia Pedroni Michele Boghi Dr. Tanguy Saget Prof. Dr. Nicolai Cramer 《Angewandte Chemie (International ed. in English)》2014,53(34):9064-9067
β‐Lactams are very important structural motifs because of their broad biological activities as well as their propensity to engage in ring‐opening reactions. Transition‐metal‐catalyzed C? H functionalizations have emerged as strategy enabling yet uncommon highly efficient disconnections. In contrast to the significant progress of Pd0‐catalyzed C? H functionalization for aryl–aryl couplings, related reactions involving the formation of saturated C(sp3)? C(sp3) bonds are elusive. Reported here is an asymmetric C? H functionalization approach to β‐lactams using readily accessible chloroacetamide substrates. Important aspects of this transformation are challenging C(sp3)? C(sp3) and strain‐building reductive eliminations to for the four‐membered ring. In general, the β‐lactams are formed in excellent yields and enantioselectivities using a bulky taddol phosphoramidite ligand in combination with adamantyl carboxylic acid as cocatalyst. 相似文献
17.
Dr. Tomoyuki Yoshimura Masatoshi Takuwa Keisuke Tomohara Makoto Uyama Dr. Kazuhiro Hayashi Pan Yang Ryuichi Hyakutake Dr. Takahiro Sasamori Prof. Dr. Norihiro Tokitoh Prof. Dr. Takeo Kawabata 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(48):15330-15336
β‐Lactams with contiguous tetra‐ and trisubstituted carbon centers were prepared in a highly enantioselective manner through 4‐exo‐trig cyclization of axially chiral enolates generated from readily available α‐amino acids. Use of a weak base (metal carbonate) in a protic solvent (EtOH) is the key to the smooth production of β‐lactams. Use of the weak base is expected to generate the axially chiral enolates in a very low concentration, which undergo intramolecular conjugate addition without suffering intermolecular side reactions. Highly strained β‐lactam enolates thus formed through reversible intramolecular conjugate addition (4‐exo‐trig cyclization) of axially chiral enolates undergo prompt protonation by EtOH in the reaction media (not during the work‐up procedure) to give β‐lactams in up to 97 % ee. 相似文献
18.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(39):12120-12124
Palladium(II)‐catalyzed C−H carbonylation reactions of methylene C−H bonds in secondary aliphatic amines lead to the formation of trans ‐disubstituted β‐lactams in excellent yields and selectivities. The generality of the C−H carbonylation process is aided by the action of xantphos‐based ligands and is important in securing good yields for the β‐lactam products. 相似文献
19.
Bin Li Hai‐Bin Song Chi‐Tung Hsu Ke‐Liang Zhang Chao Wu Hua‐Zheng Yang 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(2):o114-o117
The molecular structures of 2‐[4‐chloro‐2‐fluoro‐5‐(prop‐2‐ynyloxy)phenyl]‐1,3,4,5,6,7‐hexahydroisoindole‐1,3‐dione, C17H13ClFNO3, (I), and the isomeric compound 2‐[4‐chloro‐2‐fluoro‐5‐(prop‐2‐ynyloxy)phenyl]‐cis‐1,3,3a,4,7,7a‐hexahydroisoindole‐1,3‐dione, (II), are, as anticipated, significantly different in their conformations and in the distances between the farthest two atoms. The six‐membered ring of the 1,3,4,5,6,7‐hexahydroisoindole‐1,3‐dione moiety in (I) adopts a half‐chair conformation. The dihedral angle between the five‐membered dione ring of (I) and the benzene ring is 50.96 (7)°. The six‐membered ring of the cis‐1,3,3a,4,7,7a‐hexahydroisoindole‐1,3‐dione moiety in (II) adopts a boat conformation. The dihedral angle in (II) between the five‐membered dione ring and the benzene ring is 61.03 (13)°. In the crystal structures, the molecules are linked by C—H⋯O hydrogen bonds and weak π–π interactions. Compound (I) is a much more potent herbicide than (II). The Cl⋯H distances between the farthest two atoms in (I) and (II) are 11.37 and 9.97 Å, respectively. 相似文献
20.
Lena Decuyper Marko Juki
Izidor Sosi
Ana Maria Amoroso Olivier Verlaine Bernard Joris Stanislav Gobec Matthias D'hooghe 《化学:亚洲杂志》2020,15(1):51-55
Monocyclic β‐lactams revive the research field on antibiotics, which are threatened by the emergence of resistant bacteria. A six‐step synthetic route was developed, providing easy access to new 3‐amino‐1‐carboxymethyl‐4‐phenyl‐β‐lactams, of which the penicillin‐binding protein (PBP) inhibitory potency was demonstrated biochemically. 相似文献