Ethyl carbodiimide

Liquid chromatography/mass spectrometry Lower limit of detection Limit of detection Limit of quantitation Florseshoe crab hemocyanin Liquid scintillation counting Matrix-assisted laser desorption/ ionization mass spectrometry m -Maleimidobenzoy 1-A -Hydroxysuccinimide 1 -Cyclohexyl-3-(2-Morptiolino-ethyl)carbodiimide rnetlio-/ -Toluenesulfonate (same as CDI)... 

Metz, D.H., and Brown, G.L. (1969) The investigation of nucleic acid secondary structure by means of chemical modification with a carbodiimide reagent. I. The reaction between N-cyclohexyl-N -b-(4-methylmorpholinium)ethyl carbodiimide and model nucleotides. Biochemistry 8, 2312-2328. 

A good source of uncommon bases is tRNA. It provides substrates for studying the effect of base on the rate of hydrolysis. Baev et al. (62) showed that V2-dimethylguanylyl-(3 -5 )-cytidine-3 phosphate (G2m-pCp) was hydrolyzed much slower than the usual GpCp. Venkstern (63) reported that Tp was hydrolyzed very slowly. Naylor et al. (64) found that Cp was hydrolyzed with half the rate of CpU. The same group of workers introduced (64, 65) a chemical block on uridine and pseudo-uridine residues by reacting RNA with l-cyclohexyl-3-(2-morpho-liny]-(4)-ethyl)-carbodiimide metho-p-toluene sulfonate. The modification of the uridine residues completely blocked the action of venom exonuclease and also blocked the action of pancreatic RNase. 

Bisaziridine compounds and N-(2-chlo r o ethyl)carbodiimides have also been prepared using isocyanide dichlorides and ethyleneimine (178,179). The iodide-catalyzed rearrangement of the formerly mentioned compounds provides a method for preparing the tetrahydroimidazoimidazole system ... 

Methyl-8 5-carboxy-ergoline N-(3-Dimethylaminopropyl)-N-ethyl carbodiimide Sodium hydroxide... 

A mixture of 6-(2-propenyl)-8 5-carboxy-ergoline and N-(3-dimethylaminopropyl)-N-ethyl carbodiimide in tetrahydrofuran were refluxed, with stirring and under nitrogen, for 24 h. The resultant solution was evaporated in vacuo to dryness and the residue taken up with chloroform and... 

Eledroosmotic flow (EOF) conditions were applied and yielded only 10% conversion with constant reactant movement [9]. The use of stopped-flow techniques, which periodically push and mix the flow, led to a 50% increase in yield. A change in the coupling agent from l-(3-dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride (EDCI) to dicyclohexylcarbodiimide (DCC) for reasons of limited solubility resulted in a 93% yield of the dipeptide. Batch P-dipeptide synthesis using EDCI gave a yield of 50% [6]. 

Also, l,3-bis-(2-vinyloxyethyl)thiourea is converted into N,N -bis-(2-vinyloxy)ethyl-carbodiimide using HgO in methylene chloride. ... 

To avoid any possible a — 7 conversion promoted by the anhydrous conditions during esterification Franzblau (1962) and Franzblau el al. (1963) developed a method by which the hydroxamic acids could be formed directly from the unmodified proteins in an aqueous system. This was achieved using a water-soluble carbodiimide, 1-cyclohexyl-3[2-morpholinyl-(4)-ethyl]-carbodiimide metho-p-toluene sulfonate (Fig. 5). The reaction conditions (pH 4, 25°C, in aqueous medium) eliminated any possibility of a —> 8 conversion. These conditions also precduded the possibility of hydroxyaminolysis of the natural ester linkages of collagen which will be discussed in Section V. This method, in common with all the others used to study 7-glutamyl links, was not quantitative. After subsecpient dini-... 

On the other hand, when the reaction is performed in aqueous solutions, the carbodiimides used are usually water soluble. The most useful water-soluble carbodiimides are l-ethyl-3-(3-dimethylaminopropyl)carbo-diimide (I) and l-cyclohexyl-3-[2-morpholinyl-(4)-ethyl]carbodiimide (II). 

Preparation ofS [1] A solution of N-(tert-butyloxy)carbonyliminodiacetic acid (1) (0.349 g, 1.50 mmol) in dimethyl formamide (DMF) (15 ml) was treated with N -(3-dimefhylaminopropyl)-N-ethyl-carbodiimide hydrochloride (EDC) (0.294 g, 1.54 mmol) at 25 °C. The mixture was stirred at 25 °C for 1 h, and then the amine (1 equiv.) was added and the reaction mixture was stirred for 20 h. It was then poured into 10% aqueous HCl (60 mL) and extracted with ethyl acetate (100 mL). The organic phase was washed with 10% HCl (40 mL) and saturated aqueous NaCl (2 x 50 mL), dried (NazSOr), filtered, and concentrated in vacuo to yield the diacid monoamides 2. Each of the diacid monoamides 2 was dissolved in anhydrous DMF (20 mL/mmol) and the solutions obtained were divided into three equal portions in three separate vials. Each solution was then treated with one of the three amines (1 equiv.), diisopropylefhylamine (2 equiv.), and (benzotriazol-l-yloxy)tripyr-rolidinophosphonium hexafluorophosphate (PyBOP) (1 equiv.). Each solution was stirred at 25 °C for 20 h. The respective mixture was then poured into 10% HCl and extracted with ethyl acetate. The organic phase was washed sequentially with 10% HCl, saturated aqueous NaCl, 5% aqueous NaHCOs, and further saturated aqueous NaCl, then dried (Na2SO4), filtered, and concentrated to yield the diamides 3. Each of the diamides 3 was dissolved in 4 N HCl/dioxane (32 mL/mmol) and the respective mixture was stirred at 25 °C for 45 min. The solvent was then removed in vacuo, the residue was dissolved in anhydrous DMF (28 mL/mmol), and the solution obtained was divided into three equal portions, which were placed in three separate vials. Each solution was treated with one of three carboxylic acids (1 equiv.) followed by diisopropylamine (3 equiv.) and PyBOP (1 equiv.) and the mixtures were stirred for 20 h. Each mixture was then poured into 10% HCl and extracted with ethyl acetate. The organic phase was washed sequentially with 10% HCl, saturated aqueous NaCl, 5% aqueous NaHCOs, and further saturated aqueous NaCl, then dried (Na2SO4), filtered, and concentrated in vacuo to yield the final products 5. 

In sehr guten Ausbeuten werden 5-Oxo-4,5-dihydro-l,3-oxazole bei der dehydratisieren-den Cyclisierung der Aminosauren mit zu wasserloslichen Harnstoffen reagierenden Car-bodiimiden, z. B. N-Cyclohexyl-N -[2-(4-methyl-morpholinio)-ethyl]-carbodiimid-p-to-luolsulfonat, gewonnen. 

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