37526-89-9Relevant academic research and scientific papers
Complete functionalisation of small and large diameter bromopolystyrene beads; applications for solid-supported reagents, scavengers and diversity-oriented synthesis
Thomas, Gemma L.,Ladlow, Mark,Spring, David R.
, p. 1679 - 1681 (2004)
Bromopolystyrene beads with diameters of up to 600 μm have been derivatized completely, via bromine-magnesium exchange and interception with electrophiles, to yield high quality solid-supported reagents, scavengers and solid supports for use in diversity-
Synthesis and utilization of functionalized polystyrene resins
Thomas, Gemma L.,B?hner, Christine,Ladlow, Mark,Spring, David R.
, p. 12153 - 12159 (2005)
Co-polymerised 4-bromopolystyrene has been converted to a range of polymer-supported reagents and scavengers by bromine-magnesium exchange using Oshima's trialkylmagnesate complex followed by quenching with a variety of electrophiles. Mitsunobu, halogenation and Wittig reactions, were explored to assess the utility of the resins for target oriented and diversity oriented synthesis.
Probing cytochrome P450-mediated activation with a truncated azinomycin analogue
Vinader, Victoria,Sadiq, Maria,Sutherland, Mark,Huang, Mengying,Loadman, Paul M.,Elsalem, Lina,Shnyder, Steven D.,Cui, Hongjuan,Afarinkia, Kamyar,Searcey, Mark,Patterson, Laurence H.,Pors, Klaus
, p. 187 - 191 (2015/02/05)
A deactivated alkene precursor (IC50 = 81 μM) to the azinomycin epoxide natural product can be bioactivated by several cytochromes P450 (CYP) to generate antiproliferative metabolites with increased potency (IC50 = 1-30 μM) in CHOwt cells. CYP1A1 and 3A4 were shown to generate exclusively the unnatural and the natural-configured azinomycin epoxide diastereoisomer respectively, while CYP1B1 produced both epoxides in a 3:1 mixture. The antiproliferative activity is linked to DNA damage as demonstrated using the comet assay. This journal is
Direct esterification of carboxylic acids with alcohols catalyzed by Iron(III) acetylacetonate complex
Weng, Shiue-Shien,Chen, Fong-Kuang,Ke, Chih-Shueh
, p. 2615 - 2621 (2013/07/26)
Direct condensation of carboxylic acids and alcohols with electronic, steric, and functional group variations was carried out using the environmentally benign, moisture-stable, inexpensive, and recoverable iron(III) acetylacetonate [Fe(acac)3] as catalyst (5 mol%). This iron salt efficiently catalyzed the esterification of several primary and secondary alcohols in refluxing xylene, without the need for a dehydration reagent. The chemoselectivity of the proposed protocol was demonstrated by the selective esterification of primary alcohol functionality in racemic 1-phenylethane-1,2- diol with benzoic acid. The esterification was also applicable to unmasked α-hydroxyacid, guasiaromatic, heterocyclic, and N-protected amino acids. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
O-Nitrophenyl sulfoxides: Efficient precursors for the mild preparation of alkenes
Lu, Xiao,Long, Timothy E.
supporting information; experimental part, p. 249 - 252 (2010/04/06)
(Chemical Equation Presented) o-Nitrophenyl sulfoxides were found to be efficient synthetic precursors of various alkene types. The elimination occurs in toluene and NaOAc to generate substituted and terminal alkenes. Alkene products were easily obtained in high purity due to the simultaneous precipitation of the o-nitrophenyl sulfenic acid byproduct. The methods described have practical applications for the preparation of unsaturated compounds under mild, thermolytic conditions. 2009 American Chemical Society.
PREPARATION OF ALKENES BY MILD THERMOLYSIS OF SULFOXIDES
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Page/Page column 5, (2010/07/02)
Embodiments of this disclosure, among others, encompass methods for generating alkenes under mild thermolytic conditions that can provide almost total conversion of a precursor compound to an alkene without isomerization or the need to chromatographically purify the final product By selectively blocking the amino and carboxy groups of the depvatized amino acid, the methods of the disclosure provide for the synthesis of a peptide having the vinylglycine moiety at either the carboxy or the amino terminus of the peptide The mild conditions for the thermolytic removal of an o-NO2-phenyl substituted aryl group ensure that there is minimal if any damage to thermally sensitive conjugates such as a peptide bearing the vinylglycine The methods of the present disclosure have practical applications for the preparation of unsaturated compounds under mild, thermolytic conditions.
Exploration of the molecular origin of the azinomycin epoxide: Timing of the biosynthesis revealed
Sharma, Vasudha,Kelly, Gilbert T.,Watanabe, Coran M. H.
supporting information; experimental part, p. 4815 - 4818 (2009/05/31)
(Equation Presented) Streptomyces sahachiroi whole cell feeding experiments, utilizing putative precursors labeled with stable isotopes, established that the epoxide unit of the DNA cross-linked agents, azinomycin A and B, proceeds via a valine-dependent pathway and that hydroxylation and dehydration precedes formation of the terminal epoxide. Sodium 3-methyl-2-oxobutenoate, formed through a transimination reaction, was shown to be the penultimate precursor incorporated into the azinomycin epoxide.
Direct atom-efficient esterification between carboxylic acids and alcohols catalyzed by amphoteric, water-tolerant TiO(acac)2
Chen, Chien-Tien,Munot, Yogesh S.
, p. 8625 - 8627 (2007/10/03)
A diverse array of oxometallic species were examined as catalysts for a test direct condensation of benzoic acid and 2-phenylethanol in 1:1 stoichiometry. Besides group IVB MOCl2-XH2O and TiOX 2-xH2O, group VB VOCl2-xTHF and group IVB TiO(acac)2 were found to be the most efficient and water-tolerant catalysts for the test reaction. The new neutral catalytic protocol with the optimal TiO(acac)2 tolerates many stereo/electronic structural variations in both (di)-acid (1°-3° alkyl and aryl) and (di)alcohol (1°, 2° alkyl, and aryl) components with high chemoselectivity.
Direct ester condensation from a 1:1 mixture of carboxylic acids and alcohols catalyzed by hafnium(IV) or zirconium(IV) salts
Ishihara, Kazuaki,Nakayama, Masaya,Ohara, Suguru,Yamamoto, Hisashi
, p. 8179 - 8188 (2007/10/03)
To promote atom efficiency in synthesis and to avoid the generation of environmental waste, the use of stoichiometric amounts of condensing reagents or excess substrates should be avoided. In esterification, excess amounts of either carboxylic acids or alcohols are normally needed. We found that the direct condensation of equimolar amounts of carboxylic acids and alcohols could be achieved using hafnium(IV) or zirconium(IV) salts. These metal salts are highly effective as catalysts for the selective esterification of primary alcohols with carboxylic acids in the presence of secondary alcohols or aromatic alcohols. The present methods can be applied to direct polyesterification and may be suitable for large-scale operations.
Asymmetric synthesis of the left hand portion of the azinomycins
Bryant, Helen J.,Dardonville, Christophe Y.,Hodgkinson, Timothy J.,Hursthouse, Michael B.,Malik, K. M. Abdul,Shipman, Michael
, p. 1249 - 1255 (2007/10/03)
A nine step synthesis of the left hand portion of the azinomycins is described starting from 3,3-dimethyl-acrylic acid. The approach relies on a Sharpless asymmetric dihydroxylation (AD) reaction to install the requisite (2S,3S)-stereochemistry of epoxy alcohol 4. This epoxide is converted to crystalline amide derivative 12 whose structure and absolute stereochemistry have been unambiguously established using X-ray crystallography. Coupling of epoxy alcohol (2S,3S)-4 with naphthoyl chloride 16 and subsequent manipulations furnish epoxy amide (2S,3S)-1 identical in all respects with the natural material.
