Identification and isolation of insecticidal oxazoles from Pseudomonas spp.

• Florian Grundmann,
• Veronika Dill,
• Andrea Dowling,
• Aunchalee Thanwisai,
• Edna Bode,
• Narisara Chantratita,
• Richard ffrench-Constant and
• Helge B. Bode

Beilstein J. Org. Chem. 2012, 8, 749–752, doi:10.3762/bjoc.8.85

• , Penryn, Cornwall, TR10 9EZ, UK Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand 10.3762/bjoc.8.85 Abstract Two new and five known oxazoles were identified from two different Pseudomonas strains in addition to the known pyrones pseudopyronine

• A and B. Labeling experiments confirmed their structures and gave initial evidence for a novel biosynthesis pathway of these natural oxazoles. In order to confirm their structure, they were synthesized, which also allowed tests of their bioactivity. Additionally, the bioactivities of the synthesis

• additional oxazole derivative, but which was only produced in minute amounts. WS-30581 A (6) was identified by comparing the retention time and the MS fragmentation (Supporting Information File 1, Figure S2) of the product contained in the extract, with a synthesized compound. All oxazoles showed a

Imidazole as a parent π-conjugated backbone in charge-transfer chromophores

• Jiří Kulhánek and
• Filip Bureš

Beilstein J. Org. Chem. 2012, 8, 25–49, doi:10.3762/bjoc.8.4

• -A)2 and A-π-IM-(π-D)2 push–pull systems. An initial effort to synthesize and apply azole derivatives as CT chromophores and to study their optical (non)linearities can be ascribed to Moylan, Miller, and co-workers as early as 1993 [31][32]. Donor–acceptor-substituted imidazoles, oxazoles, and

Recent advances in direct C–H arylation: Methodology, selectivity and mechanism in oxazole series

• Cécile Verrier,
• Pierrik Lassalas,
• Laure Théveau,
• Guy Quéguiner,
• François Trécourt,
• Francis Marsais and
• Christophe Hoarau

Beilstein J. Org. Chem. 2011, 7, 1584–1601, doi:10.3762/bjoc.7.187

• , direct (hetero)arylation of (benz)oxazoles for the preparation of (hetero)aryl(benz)oxazoles, which are common structural units of numerous natural products and are also employed in pharmaceuticals and materials [27]. Review Stoichiometric direct (hetero)arylation of (benz)oxazoles Dondoni first explored

• the reactivity of the 2-lithio-oxazoles resulting from the ready deprotonation, with n-BuLi at low temperature, of the most acidic C2-proton (pKa = 20–22 was suggested), which is complicated by the coexistence of a ring-open isonitrile tautomer. In particular, the treatment by trimethylstannylchloride

• by the isonitrile function, leading to the ring-close aryloxazol-2-yl palladium complex delivering products after a final reductive elimination step (Scheme 3). Catalytic direct (hetero)arylation of (benz)oxazoles Palladium- and/or copper-catalyzed direct (hetero)arylation with halides: Synthetic

Multistep flow synthesis of vinyl azides and their use in the copper-catalyzed Huisgen-type cycloaddition under inductive-heating conditions

• Lukas Kupracz,
• Jan Hartwig,
• Jens Wegner,
• Sascha Ceylan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2011, 7, 1441–1448, doi:10.3762/bjoc.7.168

• , vinyl azides can be converted into the corresponding 2H-azirines by thermolysis or alternatively by photolysis [5]. The highly reactive azirines can further react as dipolarophiles, dienophiles, electrophiles or nucleophiles [6] thereby accessing oxazoles and isoxazoles [7]. In addition, 2H-azirines

Photocycloaddition of aromatic and aliphatic aldehydes to isoxazoles: Cycloaddition reactivity and stability studies

• Axel G. Griesbeck,
• Marco Franke,
• Jörg Neudörfl and
• Hidehiro Kotaka

Beilstein J. Org. Chem. 2011, 7, 127–134, doi:10.3762/bjoc.7.18

• -1,4-diketones after hydrolysis of the primary photochemical products (photo aldol reaction) [7], whilst the reaction of oxazoles with carbonyl compounds is a convenient protocol for the stereoselective synthesis of α-amino β-hydroxy ketones [8][9] as well as highly substituted α-amino β-hydroxy acids

• reagent on the liberated benzaldehyde. Conclusion The photocycloaddition of electronically excited carbonyl compounds to isoxazoles is clearly less effective than with other five-membered aromatic or non-aromatic heterocycles (furans, thiophenes, pyrroles, oxazoles, dihydrofurans, dihydropyrroles) [1

ADDP and PS-PPh₃: an efficient Mitsunobu protocol for the preparation of pyridine ether PPAR agonists

• Paul S. Humphries,
• Quyen-Quyen T. Do and
• David M. Wilhite

Beilstein J. Org. Chem. 2006, 2, No. 21, doi:10.1186/1860-5397-2-21

• . As expected, oxazoles, thiazoles, pyrazoles, and pyridines are tolerated in this chemistry. In a limited number of cases, functionality (e.g. basic amines, benzimidazoles, indoles, etc.) caused no reaction to occur and only recovered starting materials were isolated (data not shown). We then shifted