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Organic & Biomolecular Chemistry

Trieu N Trinh, Eileen A McLaughlin, Christopher P Gordon, Ilana R Bernstein, Victoria J Pye, Kate A Redgrove, Adam McCluskey
Leveraging our quinolone-1-(2H)-one based Hedgehog signalling pathway (HSP) inhibitors we have developed two new classes of HSP inhibitors based on: l-tryptophan and benzo[1,3]dioxol-5-ylmethyl-[2-(1H-indol-3-yl)-ethyl]-amine. Synthesis of focused compound libraries identified six l-tryptophan based inhibitors, and two stimulators, of Gli at 10 μM compound concentration. 2,4-Dichloro-13 and indole 16 suppressed mRNA expression of Ptch1 in Shh LIGHT2 cells, with 13 suppressing and 16 stimulating Gli2 mRNA expression...
March 20, 2017: Organic & Biomolecular Chemistry
Satadru Sekhar Mandal, N Vijaya Ganesh, Joanna M Sadowska, David R Bundle
The dominant cell wall antigen of Brucella bacteria is the O-polysaccharide component of the smooth lipopolysaccharide. Infection by various Brucella biovars causes abortions and infertility in a wide range of domestic and wild animals and debilitating disease in humans. Diagnosis relies on the detection of antibodies to the A and M antigens expressed in the O-polysaccharide. This molecule is a homopolymer of the rare monosaccharide, 4-formamido-4,6-dideoxy-d-mannopyranose (Rha4NFo). The A epitope is created by a uniform α1,2 linked internal polymeric sequence capped by a distinct tetrasaccharide sequence defining the M antigen...
March 20, 2017: Organic & Biomolecular Chemistry
Hasan Mtiraoui, Kevin Renault, Morgane Sanselme, Moncef Msaddek, Pierre-Yves Renard, Cyrille Sabot
A novel and practical synthesis of 3-benzoylquinoxalin-2(1H)-ones from benzodiazepin-2-ones in two steps from commercially available starting materials is reported. The reaction was achieved in the presence of N-bromosuccinimide in DMSO which served both as a solvent and an oxidant. Significantly, the yet unknown ketone to alcohol fluorescence turn-on of benzoylquinoxalinones was unveiled through the preparation of a fluorescently labelled cholesterol conjugate.
March 20, 2017: Organic & Biomolecular Chemistry
Mohamed A B Mostafa, Angus E McMillan, Andrew Sutherland
The amino substituted bicyclo[4.3.0]nonane is a molecular scaffold found in a wide range of natural products and medicinal agents. Despite this, synthetic methods for the general preparation of this structural motif are sparse. Here we evaluate a diastereoselective approach for the preparation of vinylsilyl derived aminobicyclo[4.3.0]nonanes using a one-pot multi-bond forming process involving a Pd(ii)-catalysed Overman rearrangement, a Ru(ii)-catalysed ring closing enyne metathesis reaction, followed by a hydrogen bonding directed Diels-Alder reaction...
March 17, 2017: Organic & Biomolecular Chemistry
Yaxing Zhang, Jianyu Dong, Lixin Liu, Long Liu, Yongbo Zhou, Shuang-Feng Yin
Mn-Catalyzed oxidative amination of benzylic C(sp(3))-H bonds with nitriles is disclosed, which enables the synthesis of a broad range of secondary amides in moderate to excellent yields under mild conditions. The interaction between Mn(iii) and DDQ facilitates the oxidation and makes it highly efficient and selective.
March 17, 2017: Organic & Biomolecular Chemistry
Richard Kelly
Correction and removal of expression of concern for 'A unifying mechanism for the rearrangement of vinyl allene oxide geometric isomers to cyclopentenones' by Adán B. González-Pérez et al., Org. Biomol. Chem., 2014, 12, 7694-7701.
March 17, 2017: Organic & Biomolecular Chemistry
Chada Narsimha Reddy, Manda Sathish, Susanta Adhikary, Jagadeesh Babu Nanubolu, Abdullah Alarifi, Ram Awatar Maurya, Ahmed Kamal
Phenacyl azides were decomposed in basic media to generate N-unsubstituted imines which were reacted with cyclic amino acids to give an azomethine ylide that underwent [3 + 2] cycloaddition with maleimides and N-unsubstituted imines to yield various diastereoselective pyrrolidines and imidazoles respectively in a one-pot three component manner with good to excellent yields.
March 17, 2017: Organic & Biomolecular Chemistry
Chen-Fei Liu, Guo-Tai Zhang, Jun-Shu Sun, Lin Dong
Diazo compounds play an important role as a coupling partner in the synthesis of unique π-conjugated 7-azaindole derivatives via rhodium(iii)-catalyzed double C-H activation/cyclization.
March 17, 2017: Organic & Biomolecular Chemistry
Nina Shibata, Takahisa Tsuchiya, Yoshimitsu Hashimoto, Nobuyoshi Morita, Shintaro Ban, Osamu Tamura
ω-Alkynyl O-tert-butyldiphenylsilyloximes, upon treatment with odorless 4-tert-butylbenzenethiol in the presence of azobisisobutyronitrile (AIBN) in refluxing benzene, underwent addition of a thiyl radical to the alkynyl group followed by radical cyclization of the corresponding vinyl radical onto the O-silyloxime moiety to give cyclic O-silylhydroxylamines in good yields. The reactivity of O-silyloximes in radical cyclization was similar to or even higher than that of O-benzyloximes. Facile removal of the silyl group of the cyclization products leading to hydroxylamines and nitrone formation of the hydroxylamines were also demonstrated...
March 16, 2017: Organic & Biomolecular Chemistry
A Vanessa Saura, M Isabel Burguete, Francisco Galindo, Santiago V Luis
Three bichromophoric compounds containing anthracene and bodipy moieties connected by different spacers have been synthesized and fully characterized. The set of spacers comprises a variety of bridges (short and flexible 1,2-diaminoethane in compound 1a, long and flexible 1,8-diaminooctane in compound 1b and short and rigid piperazine in compound 1c). The new compounds show interchromophoric communication via Electronic Energy Transfer (EET). When anthracene is excited, the energy is efficiently transferred to the bodipy moiety...
March 15, 2017: Organic & Biomolecular Chemistry
A Daryl Ariawan, James E A Webb, Ethan N W Howe, Philip A Gale, Pall Thordarson, Luke Hunter
Unguisin A (1) is a marine-derived, GABA-containing cyclic heptapeptide. The biological function of this flexible macrocycle is obscure. Here we show that compound 1 lacks any detectable activity in antimicrobial growth inhibition assays, a result that runs contrary to a previous report. However, we find that 1 functions as a promiscuous host molecule in a variety of anion-binding interactions, with high affinity particularly for phosphate and pyrophosphate. We also show that a series of rigidified, backbone-fluorinated analogues of 1 displays altered affinity for chloride ions...
March 15, 2017: Organic & Biomolecular Chemistry
Kensaku Anraku, Shun Sato, Nicholas T Jacob, Lisa M Eubanks, Beverly A Ellis, Kim D Janda
Carbohydrate antigens displaying Galα(1,3)Gal epitopes are recognized by naturally occurring antibodies in humans. These anti-Gal antibodies comprise up to 1% of serum IgG and have been viewed as detrimental as they are responsible for hyperacute organ rejections. In order to model this condition, α(1,3)galactosyltransferase-knockout mice are inoculated against the Galα(1,3)Gal epitope. In our study, two α-Gal trisaccharide epitopes composed of either Galα(1,3)Galβ(1,4)GlcNAc or Galα(1,3)Galβ(1,4)Glc linked to a squaric acid ester moiety were examined for their ability to elicit immune responses in KO mice...
March 15, 2017: Organic & Biomolecular Chemistry
Tsutomu Hoshino
The enzymatic polycyclization reactions catalyzed by oxidosqualene (OXSQ) cyclases (OSCs) proceed with complete regio- and stereospecificity, leading to the formation of new C-C bonds and chiral centers and to the generation of diverse polycyclic sterols and triterpenoids. The diverse structural array is remarkable, and approximately 150 different carbon frameworks have been found. Detailed investigations on squalene-hopene cyclase (SHC) and lanosterol synthase (LaS) have been reported, but progress in the study of β-amyrin synthase, which is ubiquitously found in plants, has lagged in comparison...
March 15, 2017: Organic & Biomolecular Chemistry
Ying Zhang, Duanyang Kong, Rui Wang, Guohua Hou
A highly enantioselective hydrogenation of cyclic imines for synthesis of chiral cyclic amines has been realized. With the complex of iridium and (R,R)-f-spiroPhos as the catalyst, a range of cyclic 2-aryl imines were smoothly hydrogenated under mild conditions without any additive to provide the corresponding chiral cyclic amines with excellent enantioselectivities of up to 98% ee. Moreover, this method could be successfully applied to the synthesis of (+)-(6S,10bR)-McN-4612-Z.
March 15, 2017: Organic & Biomolecular Chemistry
José A Carmona, Gonzalo de Gonzalo, Inmaculada Serrano, Ana M Crespo-Peña, Michal Šimek, David Monge, Rosario Fernández, José M Lassaletta
A series of peracylated glycosamine-derived thioureas have been synthesized and their behavior as bifunctional organocatalysts has been tested in the enantioselective nucleophilic addition of formaldehyde tert-butyl hydrazone to aliphatic α-keto esters for the synthesis of tertiary azomethyl alcohols. Using the 1,3,4,6-tetra-O-acetyl-2-amino-2-deoxy-β-d-glucosamine derived 3,5-bis-(trifluoromethyl)phenyl thiourea the reaction could be accomplished with high yields (75-98%) and moderate enantioselectivities (50-64% ee)...
March 15, 2017: Organic & Biomolecular Chemistry
Andrea Carella, Gabriel Ramos Ferronatto, Emanuela Marotta, Andrea Mazzanti, Paolo Righi, Claudio Paolucci
The acid-promoted crystallization-induced diastereoisomer transformation (CIDT) of naphthoxazines derived from racemic O-protected 2-substituted 4-hydroxybutyraldehydes and enantiopure Betti's base allows the deracemization of the starting aldehydes with ee up to 96%. As an alternative, reduction with lithium aluminum hydride of the diastereoisomerically enriched naphthoxazines leads to enantioenriched primary amines. The utility of the latter strategy was demonstrated by applying it to the synthesis of enantioenriched fenpropimorph and to the first synthesis of enantiopure amorolfine, with ee up to 99...
March 15, 2017: Organic & Biomolecular Chemistry
S M Forget, Jungwook Na, N E McCormick, D L Jakeman
Deletion of the biosynthetic 4,6-dehydratase gene, jadT, present in the angucycline jadomycin dideoxysugar biosynthetic pathway, led to the isolation of a novel C12 glucosylated jadomycin. JadS was identified as the catalyst responsible for glucosylation due to a loss of production of the glucosylated natural product in a ΔjadSΔjadT deletion strain. This study demonstrates that a 2,6-dideoxy-l-sugar glycosyltransferase is able to transfer d-glucose, exemplifying remarkable substrate tolerance.
March 14, 2017: Organic & Biomolecular Chemistry
Dan Wang, Kuan Zhang, Luhan Jia, Danting Zhang, Yue Zhang, Yujia Cheng, Chang Lin, Bo Wang
Presented here is the first example of synthesizing an array of primary-, secondary-, and tertiary-α-ketoamides with a non-metal catalyst nBu4NI from methyl ketones and inexpensive readily available amine/ammonium salts; the reactions proceeded smoothly under mild conditions, TBHP was used as an oxidant and the corresponding α-ketoamides were afforded in moderate to excellent yields.
March 14, 2017: Organic & Biomolecular Chemistry
Jing Zhang, Rao Kolluri, Salvador G Alvarez, Mark M Irving, Rajinder Singh, Matthew A J Duncton
A homo-chiral synthesis of (7R,8aS)-octahydro-5,5-dimethylindolizin-7-amine 8 and (7S, 8aS)-octahydro-5,5-dimethylindolizin-7-ol 9, amine building blocks which have found applications within the pharmaceutical industry, is presented. The approach uses a Novozym 435-mediated kinetic resolution of racemic octahydroindolizine (indolizidine) alcohol 13 as a key step (up to 100 g scale).
March 14, 2017: Organic & Biomolecular Chemistry
Xiaodong Jia, Shiwei Lü, Yu Yuan, Xuewen Zhang, Liang Zhang, Liangliang Luo
A dual removable activating group enabled Povarov reaction of N-arylalanine esters was reported. N-Arylalanine ester was utilized as the sole carbon source to generate N-arylimine and its tautomer, enamine, in situ by aerobic oxidation of sp(3) C-H bonds, and then the consecutive reaction delivered the desired quinoline-4-carboxylate esters in high yields.
March 14, 2017: Organic & Biomolecular Chemistry
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