نتایج جستجو برای: nitrogen transfer reagent
تعداد نتایج: 422007 فیلتر نتایج به سال:
To the Editor: We read with interest a paper on phospholipid analysis in this journal (1) but deferred comment until the publication of our own paper on the subject, which we believe contains relevant material (2). Sandhu refers to the formation of a Prussian blue complex as the result of a reaction between phospholipids and a chromogenic reagent containing molybdenum. Clearly this cannot be so...
2-Benzyloxy-1-methylpyridinium triflate (1) is emerging as a mild, convenient, and in some cases uniquely effective new reagent for the synthesis of benzyl ethers and esters. This article provides a revised benzyl transfer protocol in which N-methylation of 2-benzyloxypyridine delivers the active reagent in situ. Observations on the appropriate choice of solvent (toluene vs. trifluorotoluene) a...
the effects of inoculation of thiobacillus and the type of nitrogen fertilization (urea and ammonium sulphate fertilizers) on yield and yield components of rapeseed cultivars (okapi, slm 046 and reagent * cobra) were studied. the experiment was carried out as spilit plot factorial in randomized complete block design with 4 replications in shahrood university of technology. reagent * cobra culti...
The first example of intramolecular oxyalkynylation of nonactivated alkenes using oxidative Pd chemistry is reported. Both phenol and aromatic or aliphatic acid derivatives could be used under operator-friendly conditions (room temperature, technical solvents, under air). The discovery of the superiority of benziodoxolone-derived hypervalent iodine reagent 3d as an alkyne transfer reagent furth...
Studies on SmI2-mediated spirocyclisation and lactone reduction culminate in a telescoped sequence in which additives are used to "switch on" individual steps mediated by the electron transfer reagent. The sequence involves the use of two activated SmI2 reagent systems and a silicon stereocontrol element that exerts complete diastereocontrol over the cyclisation and is removed during the final ...
selective desulfurization of thiocarbonyls to carbonyls thioacetalization of aldehydes and ketones a useful reagent system for the dethioacetalization reactions
Three laboratory-prepared urease reagents were compared with a commercial preparation supplied for routine use on the Beckman Blood Urea Nitrogen Analyzer. There were discrepancies in results for urea nitrogen among the four urease reagents when matching serum and the corresponding oxalate/fluoride treated plasma were compared as measured with the Beckman Analyzer and continuous-flow (AutoAnaly...
Starting with its discovery [1] and correct structural assignment [2], Meldrum’s acid (1) has become a widely used reagent in organic synthesis [3]. In general, nucleophilic attack occurs at the carbonyl carbon atoms followed by ring fragmentation. Under basic conditions, the anion acts as a nucleophile itself to generate methylene Meldrum’s acid (2) derivatives. In contrast to a great number o...
Introduction of a difluoromethyl (CF2H) unit into organic molecules is of specific interest in medicinal chemistry and chemical biology, as compounds with a CF2H moiety can act as an isostere to molecules having a methanol (CH2OH) unit with improved lipophilicity. Among several strategies for the synthesis of CF2H compounds available, a late-stage difluoromethylation using easy-to-handle reagen...
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