Azo anions in synthesis. Use of trityl- and diphenyl-4-pyridylmethyl-hydrazones for reductive C–C bond formation from aldehydes and ketones
作者:Jack E. Baldwin、Jeffrey C. Bottaro、Jayant N. Kolhe、Robert M. Adlington
DOI:10.1039/c39840000022
日期:——
The lithium salts for trityl- and diphenyl-4-pyridylmethyl-hydrazones of both aldehydes and ketones react with electrophiles (alkyl haldies, aldehydes, and ketones) at low temperature to form C-trapped azo compounds; these intermediates decompose homolytically with loss of nitrogen below room temperature and can be diverted in a synthetically useful way to alkanes, or alkenes, or alcohols.
On the mechanism of the deoxygenation of secondary alcohols by the reduction of their methyl xanthates by tin hydrides
作者:Derek H.R. Barton、David Crich、Antonius Löbberding、Samir Z. Zard
DOI:10.1016/s0040-4020(01)90614-3
日期:1986.1
Two alternate proposals for the mechanism of reduction of xanthates by tributylstannane have been examined. Evidence has been secured that under normal reduction conditions the thiocarbonyl group is attacked reversibly. At a high enough temperature the carbon radical fragments to give eventually the reduction product. Under modified conditions, where no reducing agent (Sn-H) is present, the radical
Macromolecules having hydrazide attachment moieties and reagents for their production
申请人:——
公开号:US20040087807A1
公开(公告)日:2004-05-06
This invention relates to attachment chemistries for binding macromolecules to a substrate surface or to other conjugation targets. More particularly, this invention relates to attachment chemistries involving branched or linear structures having one or more hydrazide attachment moieties for binding the macromolecules to a substrate surface, or for other conjugation reactions. Novel modifying reagents are provided for the introduction of protected hydrazide attachment moieties or precursor forms of such hydrazides to the macromolecule, either as a single hydrazide or as multiple hydrazides.
BIOMOLECULES HAVING MULTIPLE ATTACHMENT MOIETIES FOR BINDING TO A SUBSTRATE SURFACE
申请人:Schweitzer Markus
公开号:US20100286377A1
公开(公告)日:2010-11-11
Methods of binding biomolecules to a substrate are provided that include contacting the biomolecule with a branched linking moiety to form a branched linking structure. The branched linking structure is then contacted with a binding moiety on the substrate to form a coupled substrate binding structure, thereby binding the biomolecule to the substrate. The biomolecule may contain a Lewis base or a nucleophile to react with a Lewis acid or electrophile in the branched linking moiety. Alternatively, the biomolecule may contain a Lewis acid or electrophile that can react with a Lewis base or nucleophile in the branched linking moiety. Additionally, the biomolecule can be bound to the substrate through a covalent or non-covalent bond.
Site-Selective Dehydroxy-Chlorination of Secondary Alcohols in Unprotected Glycosides
作者:Ji Zhang、Niels R. M. Reintjens、Jayaraman Dhineshkumar、Martin D. Witte、Adriaan J. Minnaard
DOI:10.1021/acs.orglett.2c01992
日期:2022.7.29
To circumvent protecting groups, the site-selective modification of unprotected glycosides is intensively studied. We show that site-selective oxidation, followed by treatment of the corresponding trityl hydrazone with tert-butyl hypochlorite and a H atom donor provides an effective way to introduce a chloride substituent in a variety of mono- and disaccharides. The stereoselectivity can be steered
为了规避保护基团,对未受保护的糖苷的位点选择性修饰进行了深入研究。我们表明,位点选择性氧化,然后用次氯酸叔丁酯和 H 原子供体处理相应的三苯甲基腙,提供了一种在各种单糖和二糖中引入氯化物取代基的有效方法。立体选择性是可以控制的,并且还描述了一种新的孪生二氯化反应。这一策略挑战了导致过度氯化的现有方法。