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Lactams (3):
Recent article
Lactams
Abstract
The 17-oxo-17a-aza-d-homo-5-androsten-3beta-yl esters (13-22) were synthesized from commercially available (25R)-5-spirosten-3beta-ol (Diosgenin) (6) as starting material. The synthesized compounds were evaluated for their antiproliferative activity, acute toxicity and effect on serum androgen level...
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PMID: 20171759
PDF is available here.
PDF is available here.
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Abstract
Alpha-amino-beta-hydroxy-gamma-lactam 1 is a peptide mimic in which the Ser/Thr residue omega-, psi-, and chi-dihedral angle geometry all are constrained by the 5-membered lactam ring. Lactams 1 were made by employing N-(Fmoc)oxiranylglycine 3 as a bis-electrophile in TFE with cat. BzOH to sequentia...
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PMID: 20225885
PDF is available here.
PDF is available here.
Abstract
Spirocyclic carbazole- and acridine-lactams were prepared by Fischer-indole or Friedländer-quinoline synthesis starting from spirocyclic ketones with a lactam ring. All annulation products were obtained as mixtures of separable regioisomers, which differ only in the position of one methyl group. Th...
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PMID: 20449495
PDF is available here.
PDF is available here.
Abstract
Screening an extract library of >2500 southern Australian and Antarctic marine invertebrates and algae for modulators of glycine receptor (GlyR) chloride channels identified three Irciniidae sponges that yielded new examples of a rare class of glycinyl lactam sesterterpene, ircinialactam A, 8-hydrox...
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PMID: 20346682
PDF is available here.
PDF is available here.
Abstract
Conjugation of amide and lactam subunits by a 'Click' type approach provides access to structural mimics of the oxazolomycin series of natural products, some of which exhibit antibacterial activity.
2010 Elsevier Ltd. All rights reserved.
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PMID: 20223659
PDF is available here.
PDF is available here.
Abstract
Two new hetero-spirocyclic gamma-lactams, azaspirofurans A (1) and B (2), had been isolated from a marine sediment-derived fungus Aspergillus sydowi D2-6. Their structures were determined by the chemical evidence and spectral analyses. Compound 1 exhibited cytotoxicity against A549 cell line with th...
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PMID: 20422356
PDF is available here.
PDF is available here.
Abstract
The synthesis and structure-activity relationships of a series of new penems bearing ferrocenyl group attached to the C-2 position of the penem nucleus were described. The beta-lactanic derivatives obtained had been characterized as sodium salts, through (1)H NMR and IR, as well as through element a...
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PMID: 20053481
PDF is available here.
PDF is available here.
Chemical Communications (46)8 2010
Abstract
An efficient and simple two-step procedure for the formation of hydroxy-Freidinger lactams is presented. The methodology allows assembly of the cyclic threonine motif (cThr) in solution and on solid support during conventional peptide synthesis.
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PMID: 20449272
PDF is available here.
PDF is available here.
Abstract
A series of novel podophyllotoxin (PDT) analogues was synthesized in which the lactone moiety was shifted to C ring. Some of the derivatives were also synthesized with modified A ring. Analogues 23 and 25 exhibited potent in vitro cytotoxicity against colon cancer (CaCO(2)) cell line. p-Demethylated...
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PMID: 20118588
PDF is available here.
PDF is available here.
Abstract
Staurosporine, pyridone 6 and hydroxyfasudil are cyclic amide (pyridone/lactam) moiety containing heterocycles that are discovered/developed as potent protein kinase inhibitors targeting on the ATP (Adenosine-5'-triphosphate) binding pocket. Despite different molecular shapes (pentacycle, tetracycle...
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PMID: 20214566
PDF is available here.
PDF is available here.
Abstract
The regiochemistry of the intramolecular Schmidt reaction of 2-azidoalkylketones is controlled by placing a thioether substituent at the position adjacent to the ketone to provide access to a family of unsubstituted medium bridged twisted amides. This outcome is ascribed to the presence of stabilizi...
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PMID: 19722508
PDF is available here.
PDF is available here.
Journal of Organic Chemistry (74)19 2009
Abstract
I and type II sensitizers. In most cases, photooxidations gave complex mixture of products. Among these products, 5,5- or 6,5-bicyclic lactams (11, 15, and 19), maleimide 12 unsaturated gamma-lactams (16 and 20), 5-hydroxylactams (13, 17, and 21), and 5-methoxylactams (14, 18, and 22) were isolated...
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PMID: 19739608
PDF is available here.
PDF is available here.
Abstract
These results suggest that the morpholinoethyl esters of LK-157 and sanfetrinem could be further investigated to assess bioavailability in vivo....
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PMID: 19703371
PDF is available here.
PDF is available here.
Abstract
Olefinic-amide and olefinic-lactam cyclization reactions that result in the generation of cyclic enamides are described.
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PMID: 19719209
PDF is available here.
PDF is available here.
Abstract
The unique reactivity of sulfoxonium ylides as a carbene source is described for a variety of X-H bond insertions, taking advantage of a simple, commercially available iridium catalyst. This method has applications in both intra- and intermolecular reactivity, including a practical ring-expansion st...
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PMID: 19618903
PDF is available here.
PDF is available here.
Abstract
A cryptand-rhodamine conjugated chemodosimeter can detect Hg(II) ion in aqueous medium selectively at ppb level in the presence of other biologically relevant metal ions and also shows a good viability to the HEK 293 cell line.
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PMID: 19597611
PDF is available here.
PDF is available here.
Natural Product Reports (26)8 2009
Abstract
We aim to emphasize the structural originality of these compounds, their biological properties and the synthetic efforts developed to reach them; 157 references are cited....
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PMID: 19636449
PDF is available here.
PDF is available here.
Abstract
We developed an assay for spiral formation and applied it to 17 new (+/-)-rhazinilam analogs with either a modified side chain or a different size D ring. There was reasonable correlation between spiral formation and inhibition of human MCF-7 breast carcinoma cell growth. Only one side chain analog...
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PMID: 19497297
PDF is available here.
PDF is available here.
Abstract
We now report that alpha'-hydroxyenones, which can be prepared in a single convenient step from aromatic and heteroaromatic aldehydes, can serve as efficient surrogates for enals in the annulation reactions. This protocol allows the facile preparation and use of substrates bearing nitrogen heterocyc...
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PMID: 19530737
PDF is available here.
PDF is available here.
Abstract
The enantioselective total synthesis of the potent alpha-glucosidase inhibitors schulzeine A, B, and C and a revision of the proposed C20' configuration of schulzeine A are reported. The central feature of our convergent route to this family of novel marine natural products is the preparation of the...
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PMID: 19361223
PDF is available here.
PDF is available here.
ChemBioChem (10)7 2009
Abstract
We have established a novel methodology for the ribosomal synthesis of peptides featuring C-terminal cyclization and various modifications, including macrocyclization, by making use of genetic code reprogramming. The C-terminal amide modification of linear and cyclic peptides should enhance their ph...
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PMID: 19370739
PDF is available here.
PDF is available here.
Abstract
The genes encoding omega-laurolactam hydrolases from Cupriavidus sp. T7, Acidovorax sp. T31, Cupriavidus sp. U124, and Sphingomonas sp. U238 were cloned and sequenced. Nucleotide and amino acid sequence analysis of the four genes indicated that the primary structures of these omega-laurolactam hydro...
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PMID: 19420719
PDF is available here.
PDF is available here.
Abstract
A series of new benzolactam derivatives was synthesized and the derivatives were evaluated for their affinities at the dopamine D(1), D(2), and D(3) receptors. Some of these compounds showed high D(2) and/or D(3) affinity and selectivity over the D(1) receptor. The SAR study of these compounds revea...
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PMID: 19217777
PDF is available here.
PDF is available here.
Medicinal Chemistry (5)2 2009
Abstract
We observed that the tubulin-Cyn complex is poorly reversed. Cyn did not bind to sulfhydryl groups and the measure of the extent of binding is 1.6 +/- 0.2 suggesting two potential binding sites. Then, we demonstrated by competition measurements that Cyn did not interact to colchicine, Taxol and Vinc...
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PMID: 19275717
PDF is available here.
PDF is available here.
Abstract
We have computed the electronic spectrum in the visible range of a squaraine dye, either isolated or embedded into a tetralactam macrocycle. The amplitude of the bathochromic displacement induced by the complexation is well-reproduced by the most accurate models. This total shift is split into speci...
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PMID: 19209370
PDF is available here.
PDF is available here.
Abstract
Stereoselective differences in pharmacokinetics between clausenamide (CLA) enantiomers have been found after intravenous and oral administration of each enantiomer to rats. The differences could be associated with protein binding of CLA enantiomers. By equilibrium dialysis methods, the binding of CL...
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PMID: 18655159
PDF is available here.
PDF is available here.
Abstract
The scope and limitation of the ring-opening reaction of sulfonyl-activated aziridines using lithiated dithianes was investigated. Nucleophilic attack of lithiated dithianes on aziridines containing tert-butylsulfonyl (Bus) and 2-(trimethylsilyl)ethylsulfonyl (SES) demonstrated efficient ring cleava...
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PMID: 19156316
PDF is available here.
PDF is available here.
Journal of Antibiotics (62)4 2009
Abstract
Abstract
We developed a henipaviral entry assay based on a beta-lactamase-Nipah Matrix (betala-M) fusion protein. We first codon-optimized the bacterial betala and the NiV-M genes to ensure efficient expression in mammalian cells. The betala-M construct was able to bud and form virus-like particles (VLPs) th...
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PMID: 19646266
PDF is available here.
PDF is available here.
Abstract
The compound 1-(2,6-dichlorophenyl)indolin-2-one (1), planned as a pro-drug of diclofenac (2), was easily synthesized in 94% yield by an intramolecular reaction in the presence of coupling agent (i.e., EDC). Compound 1 showed anti-inflammatory and analgesic activity without gastro-ulcerogenic effect...
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PMID: 19783917
PDF is available here.
PDF is available here.
Abstract
We have designed a novel compound, 3-hydroxy-3-(4-methoxyphenyl)-1-methyl-1,3-dihydro-indol-2-one (YWI92), based on a lactam structural class, and evaluated its modulation of human neuronal sodium channel isoform (hNa(v))1.2 currents and hippocampal neuron action potential firing. Furthermore, we ha...
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PMID: 18952887
PDF is available here.
PDF is available here.
Abstract
Abstract
Abstract
Cyclic sulfonyl imines derived from ketones were identified as stable and readily prepared compounds that serve as superior electrophiles for N-heterocyclic carbene (NHC)-catalyzed annulations with alpha,beta-unsaturated aldehydes to afford highly substituted gamma-lactams. Their superior reactivity...
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PMID: 19053399
PDF is available here.
PDF is available here.
Abstract
Chelated enolates are versatile nucleophiles for Michael additions to alpha,beta-unsaturated allylic esters. By quenching the reaction with TMSCl and heating a subsequent Ireland-Claisen rearrangement can occur. Direct cyclisation of the rearrangement product gives rise to highly substituted pyroglu...
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PMID: 19039375
PDF is available here.
PDF is available here.
Abstract
We synthesized analogues with a range of LG potentials and determined their IC 50 values for inhibition of chymotrypsin-like (CT-L), trypsin-like (T-L), and caspase-like (C-L) activities of 20S proteasomes. Proteasome activity was also determined before and after attempted removal of the inhibitors...
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PMID: 18939815
PDF is available here.
PDF is available here.
Journal of Organic Chemistry (73)21 2008
Abstract
A fast and acid-free one-pot 0.2-30 mmol microwave methodology for direct ionic liquid-mediated preparation of lactams from lactones and primary amines has been developed. The protocol was investigated with a wide range of primary amines and a handful of lactones, including substrates with acid-sens...
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PMID: 18826282
PDF is available here.
PDF is available here.
Journal of Organic Chemistry (73)20 2008
Abstract
Dithiocarbamate-substituted lactams, prepared through group-transfer cyclization reactions of carbamoyl radicals, undergo a Chugaev-like thermal elimination of the dithiocarbamate group in refluxing diphenyl ether to form alpha,beta- and/or beta,gamma-unsaturated amides, depending on the structure o...
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PMID: 18785775
PDF is available here.
PDF is available here.
Abstract
An efficient nitro-Mannich/lactamization cascade of gamma-nitro esters with cyclic imines for the preparation of architecturally complex multicyclic piperidinone ring-containing structures has been developed. The reaction is broad in scope and stereoselective and may be coupled to an enantioselectiv...
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PMID: 18763784
PDF is available here.
PDF is available here.
Abstract
Readily available five- and six-membered lactones and N-sulfonyllactams undergo efficient addition of t-butyl propiolate, and the resulting adducts undergo cycloisomerization to six- and seven-membered cyclic ethers or amines in the presence of pyridinium acetate. The ring expansion process occurs i...
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PMID: 18707105
PDF is available here.
PDF is available here.
Abstract
Biologically active natural products often contain particularly challenging structural features and functionalities in terms of synthesis. Perhaps the greatest difficulties are those caused by issues of stereochemistry. A useful strategy for synthesizing such molecules is to devise methods of bond f...
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PMID: 18800131
PDF is available here.
PDF is available here.
Organocatalytic asymmetric synthesis of alpha,alpha-disubstituted alpha-amino acids and derivatives.
Abstract
We have calculated by DFT-methods the transition-state structures that account for both the diastereo- and enantioselectivity observed for the addition of oxazolones to the alpha,beta-unsaturated aldehydes. For one class of compounds, the stereoselectivity is controlled by a hydrogen-bonding interac...
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PMID: 18698775
PDF is available here.
PDF is available here.
Abstract
We have prepared a novel speculative eight-membered lactam demonstration library based on the skeletal structure of the potent antitumor marine natural product octalactin A. The basic scaffold was readily constructed in a convergent fashion via ring-closing metathesis chemistry from the correspondin...
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PMID: 18703334
PDF is available here.
PDF is available here.
Chemistry & Biology (15)8 2008
Abstract
Ansamitocins are potent antitumor maytansinoids produced by Actinosynnema pretiosum. Their biosynthesis involves the initial assembly of a macrolactam polyketide, followed by a series of postpolyketide synthase (PKS) modifications. Three ansamitocin glycosides were isolated from A. pretiosum and ful...
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PMID: 18721757
PDF is available here.
PDF is available here.
Abstract
We report a novel class of Aurora inhibitors based on a pentacyclic scaffold. A prototype pentacyclic inhibitor 32 (AKI-001) derived from two early lead structures improves upon the best properties of each parent and compares favorably to a previously reported Aurora inhibitor, 39 (VX-680). The inhi...
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PMID: 18630890
PDF is available here.
PDF is available here.
Abstract
Several omega-laurolactam degrading microorganisms were isolated from soil samples. These strains were capable of growing in a medium containing omega-laurolactam as sole source of carbon and nitrogen. Among them, five strains (T7, T31, U124, U224, and U238) were identified as Cupriavidus sp. T7, Ac...
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PMID: 18685217
PDF is available here.
PDF is available here.
Abstract
Homoclausenamide was synthesized for the first time, and the intramolecular cyclization study of N-methyl-3-phenyl-N-(2-(E)-phenylethenyl)-trans(cis)-oxiranecarboxamide well demonstrated how the stereochemistry affects the cyclization paths.
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PMID: 18191305
PDF is available here.
PDF is available here.
Abstract
Hypoxia is a common characteristic of locally advanced solid tumors that has been associated with diminished therapeutic response and malignant progression. Human carbonic anhydrase (hCA) hCA IX and XII isozymes are tumor associated isoforms which contribute to acidification of the tumor environment...
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PMID: 18666004
PDF is available here.
PDF is available here.
Abstract
Structure-activity relationship studies on 1alpha,25-dihydroxyvitamin D(3)-26,23-lactams (DLAMs), antagonists of vitamin D, were conducted, focusing on the substituents of the phenyl group. One of the derivatives (23S,25S)-DLAM-1P-3,5(OEt)(2), showed potent antagonistic activity with an IC(50) of 90...
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PMID: 18635349
PDF is available here.
PDF is available here.
Chemical Society Reviews (37)8 2008
Abstract
This tutorial review focuses on the recent development of rhodamine derivatives, in which the spirolactam (non-fluorescent) to ring-opened amide (fluorescent) process was utilized.
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PMID: 18648672
PDF is available here.
PDF is available here.
Carbohydrate Research (343)10-11 2008
Abstract
We describe the synthesis of sugar-fused beta-disubstituted gamma-butyrolactones, gamma-butyrolactams and a lipophilic beta-disubstituted GABA analogue as potential GABA receptor ligands, where the pharmacophore is engineered into the carbohydrate scaffold in the form of a C-fructoside. The products...
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PMID: 18378220
PDF is available here.
PDF is available here.
Organic Letters (10)14 2008
Abstract
Co(acac)2.2H2O serves as an effective precatalyst for alkylative aldol cyclizations of alpha,beta-unsaturated amides with ketones using trialkylaluminum reagents. These reactions provide beta-hydroxylactams containing three contiguous stereocenters with high levels of diastereoselection.
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PMID: 18549223
PDF is available here.
PDF is available here.
Discovery of a novel, potent and orally active series of gamma-lactams as selective NK1 antagonists.
Abstract
Strategic replacement of the nitrogen of the lead compound 1 in the original cyclic urea series with a carbon resulted in the discovery of a novel, potent and orally more efficacious gamma-lactam series of selective NK(1) antagonists. Optimization of the lactam series culminated in the identificatio...
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PMID: 18547807
PDF is available here.
PDF is available here.
Journal of Organic Chemistry (73)14 2008
Abstract
A new and highly diastereoselective tandem reaction aza-Michael/intramolecular nucleophilic substitution is presented. This unprecedented tandem reaction between N-substituted alpha-bromoacetamides and Michael acceptors proceeds with good yields and excellent diastereoselectivity to provide the corr...
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PMID: 18549283
PDF is available here.
PDF is available here.
Journal of Bacteriology (190)13 2008
Abstract
Bacterial endospore dormancy and resistance properties depend on the relative dehydration of the spore core, which is maintained by the spore membrane and its surrounding cortex peptidoglycan wall. During spore germination, the cortex peptidoglycan is rapidly hydrolyzed by lytic enzymes packaged int...
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PMID: 18456807
PDF is available here.
PDF is available here.
Engineered biosynthesis of antiprotealide and other unnatural salinosporamide proteasome inhibitors.
Abstract
A new shunt in the phenylalanine biosynthetic pathway to the nonproteinogenic amino acid L-3-cyclohex-2'-enylalanine was exploited in the marine bacterium Salinispora tropica by mutagenesis to allow for the genetic engineering of unnatural derivatives of the potent proteasome inhibitor salinosporamid...
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PMID: 18512922
PDF is available here.
PDF is available here.
Abstract
6-Substituted TpMo(CO) 2(eta-2,3,4-pyranyl)- and TpMo(CO) 2(eta-2,3,4-pyridinyl) scaffolds (Tp = hydridotrispyrazolylborato) function as reaction partners in an efficient regio- and stereocontrolled synthesis of functionalized oxa- and azabicyclo[3.2.1]octenes through a novel Brønsted acid catalyze...
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PMID: 18479131
PDF is available here.
PDF is available here.
Abstract
In the presence of diethylzinc as a stoichiometric reductant, Ni(acac) 2 functions as an efficient precatalyst for the reductive aldol cyclization of alpha,beta-unsaturated carbonyl compounds tethered to a ketone electrophile through an amide or an ester linkage. The reactions are tolerant of a wide...
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PMID: 18481861
PDF is available here.
PDF is available here.
Phytopathology (98)6 2008
Abstract
Lysobacter enzymogenes C3 is a bacterial biological control agent that exhibits antagonism against multiple fungal pathogens. Its antifungal activity was attributed in part to lytic enzymes. In this study, a heat-stable antifungal factor (HSAF), an antibiotic complex consisting of dihydromaltophilin...
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PMID: 18944294
PDF is available here.
PDF is available here.
Abstract
A new cycloartane, monocarpinine (1), incorporating a fused tetrahydrofuranyl ring, and a cytotoxic tetracyclic lactam, monomarginine (2), were isolated from a stem bark extract of the Malayan species Monocarpia marginalis. The structures of these compounds were determined using NMR and MS analysis....
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PMID: 18462006
PDF is available here.
PDF is available here.