نتایج جستجو برای: heterocyclization

تعداد نتایج: 167  

Journal: :Scientific Bulletin of the Uzhhorod University. Series «Chemistry» 2018

Journal: :ACS Catalysis 2021

The CoII-catalyzed [2+2+2] cycloaddition of functionalized diynes and phosphaalkynes resulting in the formation an array structurally interesting phosphinines is reported. A combination 1,2-bis(diphenylphosphino)benzene (dppbenz) CoI2 turned out to be most suitable active catalyst system under microwave reaction conditions. Chemoselective cyclizations presence nitriles have been observed, a num...

Journal: :The Journal of organic chemistry 2013
Thomas P Willumstad Olesya Haze Xiao Yin Mak Tin Yiu Lam Yu-Pu Wang Rick L Danheiser

Highly substituted polycyclic aromatic and heteroaromatic compounds are produced via a two-stage tandem benzannulation/cyclization strategy. The initial benzannulation step proceeds via a pericyclic cascade mechanism triggered by thermal or photochemical Wolff rearrangement of a diazo ketone. The photochemical process can be performed using a continuous flow reactor which facilitates carrying o...

Journal: :Microbiology 2005
Hiroyasu Onaka Mizuho Nakaho Keiko Hayashi Yasuhiro Igarashi Tamotsu Furumai

The biosynthetic gene cluster of goadsporin, a polypeptide antibiotic containing thiazole and oxazole rings, was cloned from Streptomyces sp. TP-A0584. The cluster contains a structural gene, godA, and nine god (goadsporin) genes involved in post-translational modification, immunity and transcriptional regulation. Although the gene organization is similar to typical bacteriocin biosynthetic gen...

Journal: :Molecules 2013
Raffaella Mancuso Bartolo Gabriele

A recyclable palladium-catalyzed synthesis of 2-methylene-2,3-dihydrobenzofuran-3-ols 2 by heterocyclization of 2-(1-hydroxyprop-2-ynyl)phenols 1 in an ionic liquid medium (BmimBF4) is presented. The process takes place under relatively mild conditions (100 °C, 5 h) in the presence of catalytic amounts (2 mol %) of PdI2 in conjunction with KI (5 equiv with respect to PdI2) and an organic base, ...

Journal: :Chemistry & biology 1999
R Sinha Roy N L Kelleher J C Milne C T Walsh

BACKGROUND The Escherichia coli peptide antibiotic microcin B17 (MccB17) contains four oxazole and four thiazole rings, and inhibits DNA gyrase. The role of individual and tandem pairs of heterocycles in bioactivity has not been determined previously. RESULTS The two tandem 4,2-bisheterocycles in MccB17 were varied by expression of MccB17 or mutants containing altered sequences at Gly39-Ser40...

Journal: :Applied and environmental microbiology 2006
Sebastian Sudek Margo G Haygood Diaa T A Youssef Eric W Schmidt

A gene cluster for the biosynthesis of a new small cyclic peptide, dubbed trichamide, was discovered in the genome of the global, bloom-forming marine cyanobacterium Trichodesmium erythraeum ISM101 because of striking similarities to the previously characterized patellamide biosynthesis cluster. The tri cluster consists of a precursor peptide gene containing the amino acid sequence for mature t...

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