A series of novel pyrazole oxime derivatives containing oxazole ring were designed and synthesized. The title compounds were structurally confirmed by 1H NMR, 13C NMR spectra and elemental analyses. Preliminary bioassay results showed that some of the title compounds displayed promising fungicidal activity besides insecticidal and acaricidal activity. Particularly, compound 8c exhibited potent fungicidal activity against cucumber Pseudoperonospora cubensis beyond good insecticidal activity against Aphis craccivora and Nilaparvata lugens.
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Stereochemistry of (−)-ulapualide A (65), , was revised by X-ray analysis of its complex with the protein actin. A new total synthesis of 65 was reported, the first to yield a product that corresponds with the natural product. The synthesis involved the macrolactamization of the intermediate 66, followed by elaboration of the central oxazole ring in 65 as a late step in the overall synthesis [,].
ROBINSON : A NEW SYNTHESIS OF OXAZOLE DERIVAT[VES
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The cytotoxic thiazoline, apratoxin A (37), , was synthesized in 18 steps and 18% overall yield. In addition, an oxazoline analogue (38) and 34-epiapratoxin A (39) were obtained . The synthetic strategy to obtain apratoxin A involves the preparation of fragment 40 through a stereoselective route based in three asymmetric reactions. Thiazoline formation was successfully accomplished from a Cys amide using Ph3PO/Tf2O and macrolactamization was performed between N-methylisoleucine and proline residues using HATU.
Synthesis of Oxazole Derivatives from Amides and Ketones.
Two novel 2, 5-diphenyl oxazole derivatives were isolated from the endemic medicinal plant of G. chinensis. The results of the cell viability assay indicated that these novel compounds showed no detectable cytotoxicity against the A549 cell.
1,3-Oxazole synthesis - Organic Chemistry Portal
Eight novel thiazole and oxazole containing cyclic peptides, microcyclamides, GL616 (17), GL582 (18), GL614A (19), GL614B (20), GL546A (21), GL546B (22), GL628 (23), GL614C (24), , were isolated from the hydrophilic extract of a Mycrocystis sp. water-bloom collected in Gelbea reservoir, Valley of Armagedon, Israel . It is the first example where acidic and modified aminoacids are incorporated in this group of ribosomally biosynthesized metabolites. The compounds were assayed against one solid tumor (A549-lung) and one leukemis (Molt-4) cell lines. Microcyclamides GL582 (18) displayed weak cytotoxicity (20% grow inhibition) against Molt-4 cell line at 10 μM/mL.
Fischer Oxazole Synthesis - Comprehensive Organic …
A large number of natural products, in particular from the marine environment, contain thiazole, oxazole, thiazolines or oxazolines heterocycles. In many cases, promising anti-tumor, antibacterial, anti-viral, anti-malaria and anthelmintic activities have been identified for these compounds. This review focusses on the isolation and structural determination, biological activities and synthetic studies of these marine products covering literature from January 2007 to June 2010.