نتایج جستجو برای: hydroxylamines

تعداد نتایج: 1000  

Journal: :Organic & biomolecular chemistry 2014
Balakrishna Dulla Neelima D Tangellamudi Sridhar Balasubramanian Swapna Yellanki Raghavender Medishetti Rakesh Kumar Banote Girish Hari Chaudhari Pushkar Kulkarni Javed Iqbal Oliver Reiser Manojit Pal

The intramolecular 1,3-dipolar cycloaddition of isovanillin derived N-aryl hydroxylamines possessing ortho-allylic dipolarophiles affords novel benzo analogues of tricyclic isoxazolidines that can be readily transformed into functionalized lactams, γ-aminoalcohols and oxazepines. The corresponding N-unsubstituted hydroxylamines give rise to tetrahydroisoquinolines. Anxiogenic properties of thes...

Journal: :Chemical & pharmaceutical bulletin 2002
Shizuyo Horiyama Kiyoko Suwa Masae Yamaki Hiromi Kataoka Toyoshi Katagi Mitsuo Takayama Takae Takeuchi

Hydroxylamines gradually undergo oxidation to their oximes on being dissolved in organic solvent (e.g. methanol). This phenomenon was followed by (1)H-NMR and liquid chromatography-mass spectrometry (LC-MS). The oxidation rate was estimated from the peak area observed on the mass chromatogram at the protonated molecule or fragment ion on LC-atmospheric pressure chemical ionization (APCI)-MS. Th...

Journal: :Organic & biomolecular chemistry 2010
S Irene Medina Jian Wu Jeffrey W Bode

The synthesis of enantiopure N-benzylidene nitrones of N-hydroxy-alpha-amino acids and their incorporation using standard Fmoc-based peptide chemistry into solid-supported peptide chains is described. Deprotection and resin cleavage affords N-terminal peptide hydroxylamines, which are the key substrates for chemoselective ligations with C-terminal peptide alpha-ketoacids. This general route is ...

Journal: :Green Chemistry 2021

?-hydroxylamines exhibit higher reactivity toward cyclic carbonates compare to regular amines and allowed access fully biobased polyhydroxyurethanes.

2011
Hideto MIYABE Katsuhiko MORIYAMA Yoshiji TAKEMOTO

tions have been developed as fundamentally important crosscoupling reactions. In general, the heteroatom nucleophiles in these reactions have been largely limited to alkylamines, anilines, carboxylates and phenols. Our laboratory is interested in searching the synthetically useful heteroatom nucleophiles for the synthesis of functionalized allylic compounds (Fig. 1). As our successful examples,...

Journal: :The Journal of biological chemistry 2000
H Atamna A Paler-Martínez B N Ames

Alpha-phenyl-N-t-butyl nitrone (PBN), a spin trap, scavenges hydroxyl radicals, protects tissues from oxidative injury, and delays senescence of both normal human lung fibroblasts (IMR90) and senescence-accelerated mice. N-t-butyl hydroxylamine and benzaldehyde are the breakdown products of PBN. N-t-Butyl hydroxylamine delays senescence of IMR90 cells at concentrations as low as 10 microM compa...

Journal: :ACS Catalysis 2022

Gold(I) complexes of a chiral phosphoric acid-functionalized phosphine the CPA-Phos series enable enantioselective multicomponent reactions between aldehydes, hydroxylamines and cyclic yne-enones, leading to 3,4-dihydro-1H-furo[3,4-d][1,2]oxazines. This represents rare example highly reaction in gold(I) catalysis. The proceed at low catalyst loading provide high yields, total diastereoselectivi...

Journal: :Organic chemistry frontiers 2021

Oximes, its ether derivatives and the corresponding hydroxylamines rearrange to secondary amines when reacted with PhSiH3 B(C6F5)3 as catalyst. Computations suggest a reduction–rearrangement be slightly favored over Beckmann-type sequence.

2017
Zhaobing Guan Manman Ding Yao Sun Sisi Yu Ao Zhang Shuguang Xia Xiaosong Hu Yawei Lin

Herein, twoN-substituted coumaryl hydroxylamines (compounds 1a and 1b) with long aliphatic chains were prepared in 8 steps with a novel synthetic protocol. They served as derivatization agents for aldehydes by the formation of nitrones under mild conditions, which can be readily analysed by LC-MS with good chromatographic performance, excellent fluorescent response, and high ionization strength...

Journal: :Chemical communications 2004
Feng Li Jingnan Cui Xuhong Qian Rong Zhang

Using bakers' yeast as a biocatalyst, the chemoselective reduction of aromatic nitro compounds bearing electron-withdrawing groups gave the corresponding hydroxylamines with good to excellent conversion under mild conditions.

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