L-Ethyl-3- 3 dimethylamino

BuOH, EDCI (EDCI = l-ethyl-3-[3-(dimethylamino)propyl]carbodi-imide hydrochloride), DMAP, CH2CI2, 88% yield.Cbz-Proline was protected without racemization. 

Reactions of 2,3-dioxo-l,2,3,5,6,7-hexahydropyrido[l,2,3-carboxylic acids and the homologous acetic and propionic acids, prepared by basic hydrolysis of the corresponding ester, with amines, 28% NH4OH, and hydroxylamine derivatives in the presence of l-ethyl-3-[3-(dimethylamino)propyl]carbodiimide and hydroxybenztria-zole <1995BML1527>, 1995BML1533>, and in the presence of NEt3 and A, A -bis(2-oxo-3-oxazolidinyl)phosphinic... 

B. l-Eihyl-3-(3-dinuthylamino)propylcarbodiimide hydrochloride. A suspension of 34.6 g. (0.300 mole) of pyridine hydrochloride (Note 7) in 280 ml. of methylene chloride is prepared in a 1-1. Erlenmeyer flask. To this is slowly added 46.5 g. (0.300 mole) of l-ethyl-3-(3-dimethylamino)propylcarbodiimide. The resulting solution is diluted with anhydrous ether (Note 8) and stored at 0-5° for 16-20 hours. The crystalline product is collected by filtration in a dry atmosphere (Note 9), washed with a little anhydrous ether, and dried under reduced pressure over phosphorus pentoxide. The yield is 50.5-55.5 g. (88-96.5%), m.p. 104-109° (Notes 10 and 11). This material is sufficiently pure for most purposes. 

C. l-Ethyl-3- 3-dimethylamino)propylcarbodiimide methiodide. A solution of 30.0 g. (0.193 mole) of l-ethyl-3-(3-dimethylamino)-propylcarbodiimide in 750 ml. of anhydrous ether is prepared in a 2-1. Erlenmeyer flask. To this is slowly added from an addition funnel a solution of 30.0 g. (0.21 mole) of methyl iodide in 100 ml. of ether. The mixture is stored in the dark for 48 hours, after which the crystalline product is collected by filtration, washed... 

Procedures for the preparation of several compounds of considerable utility are described. These include 1,1 -carbonyl-diimidazole, which has been used in the preparation of esters, amides, and anhydrides, the hydrochloride and methiodide of l-ethyl-3-(3-dimethylamino)-propylcarbodiimide, which can be used for similar purposes and are especially useful in the preparation of peptides, and (+)- and (— )-< -(2,4,5,7-tetranitro-9-fluorenylideneaminooxy) propionic acid (TAPA), which is used for the resolution of polycyclic aromatic compounds. 

A. l-Ethyl-3-(3-dimethylamino)propylcarbodiimide. A solution of 100 g. (1.41 moles) of ethyl isocyanate (Note 1) in 750 ml. of methylene chloride is prepared in a 5-1. three-necked flask equipped with a mechanical stirrer, an immersion thermometer, and a 500-ml., pressure-equalizing, addition funnel (Note 2). The flask and its contents are cooled to 5° in an ice bath, and a solution of 144 g. (1.41 moles) of N,N-dimethyl-l,3-propanedi-amine in 250 ml. of methylene chloride is added through the addition funnel at a rate such that the reaction temperature does not exceed 10° (Note 3). On completion of this addition 500 ml. of triethylamine is added to the flask, and a solution of 300 g. (1.6 moles) of -toluenesulfony 1 chloride in 300 ml. of methylene chloride is placed in the addition funnel and added to the reaction... 

CaM was purified from porcine brain. The purity of proteins was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing. CaM and PDE were cross-linked with l-ethyl-3(3-dimethylamino-propyl) carbodiimide (EDC) or N-succinimidyl 3-(2-pyridyldithio)propionate (SPDP) in a buffer solution of 0.1 M HEPES (pH 7.1) in the presence of 1 mM CaCl2. After a buffer solution containing 2 mM EGTA added into the reaction solution, the CaM-PDE hybrid was separated from other ingredients by gel chromatography on a Sepharose CL-6B solumn. 

Weigh out 1.25 mg of the carbodiimide EDC (l-ethyl-3-(3-dimethylamino-propyl)carbodiimide hydrochloride Pierce) into a microfuge tube. 

Pyrazolooxazepine 153 was synthesized starting from the condensation of hydrazinol 151 with enaminoketone 150. When the isolated ester intermediate 152 (R = OMe) was saponified, ester hydrolysis afforded acid 152 (R = H), which cyclized on subsequent treatment with l-ethyl-3-[3-(dimethylamino)propyl] carbodiimide hydrochloride (EDC) and 1-hydroxybenzotriazole (HOBt) to form oxazepine 153 (Scheme 22) <2003TL5867>. 

Bershitsky, S., Tsaturyan, A., Bershitskaya, O., Mashanov, G., Brown, P., Webb, M., and Ferenczi, M. A. (1996). Mechanical and structural properties underlying contraction of skeletal muscle fibers after partial l-ethyl-3-[3-dimethylamino)propyl]carbodii-mide cross-linking. Biophys.J. 71, 1462-1474. 

EDCl (or EDC) l-Ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride... 

Polystyrene-supported tethered l-ethyl-3-(3-dimethylamino-propyl)carbodiimide hydrochloride (PS-EDC or PS-EDCI, 11) is also a commercially available, frequently used resin-supported carbodiimide [25], which is highly effective in the coupling of carboxylic acids and amines, in the absence of any additive the use of chloroform as solvent is essential. 

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