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Readily available α-amino aldehydes, incorporating a methylthiomethyl (MTM) protecting group on nitrogen, are shown to be efficient substrates in Rh-catalyzed alkyne hydroacylation reactions. The reactions are performed under mild conditions, employing a small-bite-angle bis-phosphine ligand, allowing for good functional group tolerance with high stereospecificity. Amino aldehydes derived from glycine, alanine, valine, leucine, phenylalanine, isoleucine, serine, tryptophan, methionine, and cysteine were successfully employed, as was an enantiomerically enriched α-OMTM-aldehyde derived from phenyllactic acid. The synthetic utility of the α-amino enone products is demonstrated in a short enantioselective synthesis of the natural product sphingosine.

An one-pot sequence of borylation and Suzuki reaction is used for the preparation of 20 bi- and polyarenes, e.g. vemurafenib precursor (IIId) and analogues (V) of kinase inhibitor GDC-0879.

Two new secondary metabolites, the xylerythrin derivative dragmacidol A (1) and the steroid dragmacidolide A (2), were isolated from a specimen of the marine sponge Dragmacidon australe, collected off the coast of the Whitsunday Islands in Queensland, Australia. Their structures were fully characterized via analysis of 1D/2D NMR and MS data. The proton-poor structure of 1 was also supported through successful 13C DFT-NMR calculations. The isolation of these two metabolites from this sponge genus is quite unusual, given that previous reports of Dragmacidon secondary metabolites have been dominated by indole and β-carboline alkaloids.

Two new tryptophan alkaloids, 6-oxofascaplysin (I) and secofascaplysic acid (II), are isolated together with the known metabolites fascaplysin and reticulatate.

Alkene and alkyne hydroacylation reactions are archetypal examples of simple addition processes that display excellent atom economy.1 Both reactions result in the formation of a new C–C bond and deliver synthetically useful carbonyl-containing products.2 In recent years, there has been considerable interest in converting these processes into synthetically useful transformations. Transition-metal-catalyzed variants represent the largest class of hydroacylation reactions, and amongst these, processes that involve some form of chelation control dominate. The need to employ a chelating substrate stems from the fact that the majority of the metal-catalyzed examples proceed through an inherently unstable acyl metal intermediate 1 (Scheme 1), which can lead to the formation of unwanted side products formed by decarbonylation. A limitation of the chelation-controlled strategy is that the coordinating group, which is present to stabilize the metal–acyl intermediate 2, will also be present in the product. If this group is not needed in the final product, then it must be removed or converted into an alternative functional group.3 Despite this limitation, the advantages of this chelation-controlled process, such as mild reaction conditions, control of enantio- and regioselectivity,4, 5 and broad substrate scope, have resulted in widespread applications of this approach. One strategy to overcome the innate limitation of a chelation-controlled approach is to develop catalytic methods that function without the need for such coordinating groups; although there are notable examples of success with this approach,2c, 6 significant limitations with regard to substrate scope and enantio- and regioselectivity remain. An alternative strategy is to consider the need for a chelating unit as an opportunity, and to expand the range of effective coordinating groups, so that a large variety of useful functional groups can act as the crucial chelating motif. As synthetic chemistry is generally concerned with the preparation of functionalized molecules, an approach that is tolerant of, or indeed benefits from, as many useful functional groups as possible should find wide application. Herein, we demonstrate that simple and readily available 2-aminobenzaldehydes are excellent substrates for intermolecular Rh-catalyzed alkyne hydroacylation, and in doing so add to the motifs available for use in these valuable processes. Furthermore, the products of these reactions, amino-substituted enones, were directly converted into a series of useful dihydroquinolone heterocycles.

A new rhodium(I) catalyst allows practical and efficient alkyne carbothiolation reactions to be achieved on synthetically useful ketone-bearing aryl methyl sulfides. The carbothiolation adducts, featuring a ‘recycled methyl sulfide’ activating group, are convenient precursors to highly substituted isoquinolines.

A novel ruthenium catalyzed cross-coupling reaction between the title substrates, which shows good functional group tolerance, is developed.

Eu1.32Ca0.68Ge2Pb (I) and Sr0.42Eu1.58Ge2Pb (II) are synthesized from mixtures of the elements by Pb flux reactions (800 °C, 5 h).

Evolutionary algorithms coupled with first-principles DFT calculations are employed to predict the structure of cesium polyhydrides under pressure.

Intermolecular hydroacylation of a wide variety of unactivated alkenes, allenes and alkynes with aromatic and aliphatic aldehydes is efficiently catalyzed by rhodium catalysts containing diphosphine ligands with small bite angles.

The optimized Rh(I)-catalyzed reaction of aryl methyl sulfides such as (I) with terminal alkynes affords arylvinyl methyl sulfides.

The reaction with a wide range of terminal alkynes affords α-O-methylthiomethyl-substituted enone products.

A mild two-step preparation of aryl and heteroaryl sulfonyl chlorides and sulfonamides from their corresponding iodides is developed. Acid labile functionalities are shown to be stable under both the copper-catalysed coupling and the subsequent oxidative chlorination.

The highly N-methylated linear polypeptides koshikamide C-E and the cyclic analogues F-H are isolated from Theonella swinhoei and Theonella cupola.

Parthenin and some of its derivatives have been shown to possess significant anti-malarial activity against a multi-drug resistant strain of Plasmodium falciparum. Structure-activity relationships in this series of compounds are discussed and possible mechanisms of action considered. Molecular matching of the oxygen atoms of parthenin and the new anti-malarial drug qinghaosu shows both molecules to be amphipathic with common areas for their oxygen atoms and hydrocarbon frameworks.

3-Alkyl-4-arylazomethylene-3,4-dihydro-1,2,3-benzotriazines 5a and 5b undergo facile 1,4-addition of methanol or ethanol to afford stable crystalline hydrazones, 6 and 8 which have been characterised by spectroscopic analysis. In particular, the nmr spectrum of 8 shows novel features due to the diastereotopic nature of the CH2 protons in the two O-ethyl groups. Compound 5b shows a property unique to the compounds in this series; refluxing this arylazomethylenetriazine in ethanol affords a rearranged product, characterised as the 1-aryl-2-cinnolinylhydrazine (9). The formation of 9 is rationalised as a ring opening-ring closure process analogous to the Dimroth rearrangement. The cinnoline 9 displays some novel chemistry arising from the facility of the arylhydrazino substituent to react with acid to give a fragmentation product, 3-methylindazole (7).

Diaminopimelic acid is an essential amino acid in the peptidoglycan of Gram-negative bacteria, mycobacteria and some Gram-positive bacteria. It can be used as a target for the development of antibacterial agents. In this article the synthesis of a series of phosphonic acid analogues of this diamino-dicarboxylic acid is described: mono- and diphosphonic acid derivatives as well as their homologues, N -alkyl analogues and some peptidyl derivatives. A phenylphosphinic derivative was also prepared. All the prepared compounds were tested for their antibacterial activity against a series of Gram-positive, Gram-negative and mycobacteria. They were also tested as possible inhibitors of the UDP-MurNAc- l -Ala-γ- d -Glu: meso -DAP synthetase. No significant biological activity was found.

The reactions of stabilized phosphoranes with cyclic anhydrides give enol-lactones as final products. The initial condensation, however, leads to the formation of acyclic adducts that are observable by NMR, can be easily trapped, and, in some cases, can be isolated. A study of the mechanism of these condensations by NMR spectroscopic methods and by various trapping experiments is described and the reaction pathway is proposed.

A series of 3-aryl-1-methyltriazene 1-oxides, with a variety of substituents in the ortho or para position, have been prepared by coupling of the appropriate diazonium salt with TV-methylhydroxylam...

Chemical investigation of a Dictyodendrilla sp. from Port Phillip Bay, Victoria, yielded three new oxygenated sesquiterpenes, dictyodendrillin -A (6), -B (7) and -C (8), together with the known sesquiterpene dendrolasin (9). Structures for all these metabolites were established by spectroscopic analysis.

A new sesterterpene tetronic acid (5) exhibiting antimicrobial activity has been isolated from an Australian marine sponge, Psammocinia sp., and its structure secured by detailed spectroscopic analysis. The tetronic acid (5) possesses almost identical spectroscopic characteristics to, and is a structural isomer of, the known marine natural product (6) previously reported from an Australian sponge.

Reaction of a series of arene diazonium salts with glycinamide affords the N-coupling products the 1-aryl-3-(carbamoylmethyl)triazenes, ArN=NNHCH2CONH2 3, which have been characterized by 1H and 13C NMR spectroscopy. The reaction works well with electron withdrawing groups in the ortho- or para-position of the aryl moiety, but when the coupling reaction was attempted with a p-bromo-substituted diazonium salt, the reaction afforded the pentazadiene 8 and not the expected triazene. Triazenes with a reactive ester or cyano-substituent in the ortho-position of the benzene ring were found to undergo spontaneous cyclization to the respective 1,2,3-benzotriazine heterocycles 4a and 5. The 3-(carbamoylmethyl)-4-imino-1,2,3-benzotriazine (5) was characterized by further NMR experiments, 15N NMR, and homonuclear correlated NMR spectra.

Reaction of arene diazonium salts with 3-aminocrotononitrile or methyl 3-aminocrotonate affords the 2-aryl-hydrazono-3-oxobutanenitrile (1 or 3 and 3′) or the methyl 2-arylhydrazono-3-oxobutanoate ...

The structures of two new bispyrroloiminoquinone alkaloids, tsitsikammamine A (1) and tsitsikammamine B (2) and two new pyrroloiminoquinone alkaloids 14-bromodiscorhabdin C (3) and 14-bromodihydrodiscorhabdin C (4) were determined spectroscopically. Compounds 1 and 2 are the first bispyrroloiminoquinone alkaloids to be isolated from a marine sponge while compounds 3 and 4 are the first reported discorhabdin metabolites with a C-14 substituent. All four compounds exhibit antimicrobial activity.

A one-pot asymmetric synthesis of primary amines from vinylarenes via catalytic hydroboration is described.

This paper describes simple and successful methods for the preparation of stabilized halogenated phosphoylides and discusses their stability, reactivity, and utility in organic synthesis. Preparations of several halogenated compounds including pharmaceutically interesting enol lactones are reported. Keywords: halogenated stabilized ylides, preparation, structure, stability, reactivity, applications; vinylic halides, halo enol lactones.

A new sesquiterpene isothiocyanate, ( – )-9-isothiocyanatopupukeanane (4), has been isolated along with the known sesquiterpene metabolites ( – )-9-isocyanopupukeanane (1), ( – )-2-thiocyanatoneopupukeanane (2) and ( – )-epipolasin-A (3) from the sponge Axinyssa sp. nov. Metabolites (1), (2) and (4) showed modest in vitro antimalarial activity.

A series of novel bistriazenes, the 1,2-bis(1-aryl-3-methyltriazen-3-yl)ethanes, Ar-N T N-NMe-CH2CH2-NMe-N T N-Ar, have been synthesized by diazonium coupling with N,N'-dimethylethylenediamine. These bistriazenes are stable crystalline compounds and have been unequivocally characterized by IR and NMR spectroscopy (1H and 13C), and elemental analysis. The structures of two compounds in the series have been confirmed by X-ray crystallography. The 1H NMR spectra show significant line broadening of the N-methyl resonances arising from the restricted rotation around the N2-N3 bond of the triazene units. The presence of strongly electron-withdrawing groups on the aryl ring restricts the rotation to the point where the N-methyl signals of the rotamers are distinct even at room temperature; four resonances of the N-methyl signal are clearly evident and these can be assigned to the anti-anti, syn-syn, and syn-anti conformations of the bistriazene. Diazonium coupling with N,N'-diethylethylenediamine affords the N,N...

In addition to aminobacteriohopanetriol and adenosylhopane, three new hopanoids were isolated from the bacterium Nitrosomonas europaea: two N-acylaminobacteriohopanetriols, a hopanoid presenting a carbon carbon bond between ribonolactone and hopane and related to a putative intermediate involved in the formation of the C35 bacteriohopane skeleton and finally a condensation product between aminobacteriohopanetriol and trinorbacteriohopan-32-al, an artifact resulting from the autoxidation of the aminotriol.