نتایج جستجو برای: 3 dpyrimidin 34h amines
تعداد نتایج: 1826702 فیلتر نتایج به سال:
Lower Lewis acidity boranes demonstrate greater tolerance to combinations of water/strong Brønsted bases than B(C6 F5 )3 , this enables Si-H bond activation by a frustrated Lewis pair (FLP) mechanism to proceed in the presence of H2 O/alkylamines. Specifically, BPh3 has improved water tolerance in the presence of alkylamines as the Brønsted acidic adduct H2 O-BPh3 does not undergo irreversible ...
The room temperature ionic liquid (IL) 1-butyl-3-methylimidazolium bis-(trifluorometanesulfonyl)imide BMIm[NTf₂] was used as a novel medium for improvement of separation and quantization of 16 aromatic amines typically present as contaminants in consumer products and detected by HPLC coupled to an electrochemical detector. The aromatic amines, namely 4,4'-diaminodiphenylmethane, 4-chloroaniline...
1HE GROWING CLINICAL interest in the action and metabolism of the catechol amines makes it highly desirable to re-evaluate existing methods for the quantitative determination of these substances in body fluids. In 1955 Persky (1) reviewed the subject, and, on the whole, his conclusion is still valid that the fluorometric determination of the catechol amines in body fluids is the most practical ...
biogenic amines (ba) are nitrogenous compounds that possess biological activity. the source of production is the microbial decarboxylation of amino acids. this compounds are found in various types of cheese. the aim of this work was to evaluate the ba content of some traditional cheeses in west azerbaijan province iran. for this purpose, 70 samples of koopeh, 10 samples of lighvan and 5 samples...
We report measurements of ambient amines and ammonia with a fast response chemical ionization mass spectrometer (CIMS) in a southeastern US forest and a moderately polluted midwestern site during the summer. At the forest site, mostly C3-amines (from pptv to tens of pptv) and ammonia (up to 2 ppbv) were detected, and they both showed temperature dependencies. Aerosol-phase amines measured therm...
Sodium triacetoxyborohydride is presented as a general reducing agent for the reductive amination of aldehydes and ketones. Procedures for using this mild and selective reagent have been developed for a wide variety of substrates. The scope of the reaction includes aliphatic acyclic and cyclic ketones, aliphatic and aromatic aldehydes, and primary and secondary amines including a variety of wea...
Several methods have been reported for the syn thesis of isocyanates, most of them involving the use of phosgene: e.g. phosgene and primary amines [1] either in basic [2] or in acidic medium [1]; phosgene and diaryl urea [1]; phosgene and l-alkyl-3-arylsulphonyl urea [3]; or phosgene and sulfinyl amines [4], Isocyanates were further synthesized from olefins or alkyl halides by the use of isocy...
vilsmeier several diamide derivatives containing 2-chloroquinoline scaffolds were synthesized via ugi reaction of 2-chloroquinoline-3-carboxaldehydes, amines, carboxylic acids and isocyanides. the diversity of these quinolinyl ugi-adducts was increased by using 2-chloroquinoline-3-carboxylic acids as a source of acid. among them, compounds 2d, 2n, 2p, 4a, 4c and 4e displayed moderate to good an...
Sulfuric acid {[3-(3-silicapropyl)sulfanyl]propyl}ester (SASPSPE) is employed as a recyclable catalyst for the synthesis of α-amino nitriles. These syntheses were performed via a one-pot three-component condensation of aldehydes, amines, and trimethylsilyl cyanide under mild reaction conditions at room temperature. The catalyst could be recycled and reused several times without any loss of effi...
Problem statement: Biogenic amines are basic nitrogenous compounds present in a wide variety of foods and beverages. Their formations were mainly due to the amino acids decarboxylase activity of certain microorganisms. Excessive intake of biogenic amines could induce many undesirable physiological effects determined by their psychoactive and vasoactive action. Fish sauce which is considered as ...
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