Diisopropyl carbodiimide

DIC (or diisopropyl carbodiimide) is another water-insoluble amide bond-forming agent that has advantages over DCC (Section 1.4, this chapter). It is a liquid at room temperature and... 

The earliest published example of microwave-assisted SPOS involved diisopropyl-carbodiimide (DlC)-mediated solid-phase peptide couplings [24], Numerous Fmoc-protected amino acids and peptide fragments were coupled with glycine-preloaded polystyrene Wang resin (PS-Wang) in DMF, using either the symmetric anhydride or preformed N-hydroxybenzotriazole active esters (HOBt) as precursors (Scheme 12.1). 

DCC= 1,3-dicyclohexylcarbodiimide, DIC = 1,3-diisopropyl-carbodiimide, EDC = 1 -ethyl-3-(3-dimethylaminopropyl)carbodiimide. 

Figure 6.7 Reaction of wood with succinic anhydride (SA) and subsequent reaction of the activated surface with hexamethylene diamine (HMDA), using diisopropyl carbodiimide (DIPCI) as a reaction promoter.

Hydrolysis of stabilizer N-N -diisopropyl carbodiimide, 17 2-3 Simplified scheme for the hydrolysis of VX, 17 2-4 Major hydrolysis pathways for mustard, 18... 

An acetylation (capping of the resin) was done after Ala, Pro and Leu with N,N -diisopropyl carbodiimide - 1-hydroxybenztriazole (HBt). Excess HBt (2 equiv.) was used for the coupling of the basic amino acids, hArg(Et)2 and Pal(3). 

Also, pentacarbonyl(diphenylcarbene)tungsten 288 reacts with DCC or diisopropyl-carbodiimide to give metathesis products, which may involve the [2-1-2] cycloadducts 289 as intermediates. ... 

However, cyclization to give 511 was observed in the reaction of 3,6,9-trioxaundecanoic dicarboxylic acid 510 with DCC. 510 was reacted with an aminomethylstyrene resin, which was also utilized in the solid phase synthesis of oligopeptides using diisopropyl-carbodiimide/HOBt and carboxyl protected amino acids." ... 

Coupling reagents A,A -dicyclohexylcarbodiimide (DCC), A,A -diisopropyl-carbodiimide (DIC), 1-hydroxybenzotriazol (HOBt), and (9-benzotriazolyl-A,A, A, A -tetramethyluronium hexafluorophosphate (HBTU)" (Fluka, or Applied Biosystems, SARF Paris, France). 

As far as alkynes are concerned, C-C coupling reactions have been reported to be catalyzed by rhodium or ruthenium clusters. Phenylacetylen can be coupled to diisopropyl carbodiimide to give 93... 

An issue of significant concern was whether GB could be analyzed in the solids that are found in the munitions. Crystals that tend to form in the munitions have been shown to be diisopropylurca, which is derived from diisopropyl carbodiimide (Rosso et al., 2005). The TRRP study showed that the analytical method worked well for detecting GB in the diisopropylurca crystals, and that GB associated with the di-isopropylurea crystals was hydrolyzed (Malloy et al., 2007). For diisopropyl trrea crystals that had been washed with caustic, residtral GB was detected at high concentrations, on the order of 70 to 450 ppm. When the diisopropylurca crystals were mixed with GB/diisopropyl carbodiimide and then added to the reactor, no GB was detected. 

Members of the public expressed concern about the different chemistries of the two layers that emerge in VX hydrolysate. Specifically, there is uncertainty over whether VX could be present in the organic layer. In examining the hydrolysates from the four batches of VX, one of the four had a layer that appeared to account for several percent of the total volume, while each of the other three had an organic layer that accounted for a much lower fraction. In TRRP activity 11, GC/MS analysis of the upper organic layer showed that it consists mainly of the disulfide, bis[2-(diisopropylamino)ethyl] disulfide, with lesser amounts of the thiolamine and related thiols, sulfides, and conjugates of those molecules with the stabilizer diisopropyl carbodiimide. VX was not detected in this analysis however, the MDL for tliis approach is not known. 

Reaction The variable add (4 equiv, 0.24—0.8 mmol) was manually added to each 16 x 100 mm tube and fhe tubes were loosely capped wifh a polypropylene cap. The hquid handler fhen carried out the following steps on each tube 1) Added 500 pL (1.5 equiv, 0.092-0.3 mmol) of a solution of hydroxybenzotriazole in DMF. 2) Added 500 pL (1.5 equiv, 0.092-0.3 mmol) of a solution of diisopropyl carbodiimide in dichloromefhane. 3) Added... 

Scheme 16.1 Solid-phase synthesis of isoxazolidines according to the split-and-combine method, (a) Distribution of the resin into two equal portions, coupling of bromocarboxylic acids with N,N -diisopropyl-carbodiimide (D1C), combination of the resin, substitution with hydroxylamine. (b) Distribution of the resin into three equal portions, condensation with three different aromatic aldehydes to the corresponding nitrones, combination of the resin, (c) Distribution of the resin into three equal portions, cyclo-addition with three different dipolarophiles to isoxazolidines, combination of the resin.

Diisopropylurea IV,/V -Diisopropy lurea N, N tns-( 1 -Methylethyl) urea c7h16n2o 4128-37-4 Hydrolysis of diisopropyl carbodiimide... 

Activation of the carboxyl group in condensation reactions can occur as an azide or, most common, with dicyclohexylcarbodiimide (DCC) or diisopropyl-carbodiimide. Neutral conditions are applied and no racemization occurs. Application of these condensation reactions is discussed in Section 9.3. 

Carbodiimide method, a procedure for peptide bond formation using carbodi-imides, R-N=C=N-R, such as dicyclohexyl carbodiimide (DCC), diisopropyl carbodiimide (DIC) and water-soluble carbodi-imides. The carbodiimide reacts in a one-pot procedure with the carboxylate anion of the carboxy component to form a highly reactive O-acylisourea intermediate. The former reacts immediately with the amino function of the amino component to yield the desired peptide derivative and the urea byproduct. Indeed, a more complex mechanism must be taken into consideration. Unwanted side reactions are racemization via the oxazolone mechanism and formation of the unreactive N-acylurea by base-catalyzed acyl migration from the isourea oxygen to nitrogen. The side reactions can be diminished by preparing the O-acylisourea at 0 °C... 

This compound has been known since 1892 and was previously synthesized in 1915 by oxidation of isatin with neutral potassium permanganate 134). Bird 135) has synthesized 53 from 0-methylisatin and o-aminobenzaldehyde. The isatin-a-(2-formylanil) 54 (appears to exist predominantly as 55) was converted to 53 by oxidation with CrO. The reaction of 7 l-sodioi satin with o-nitrobenzoyl chloride gave l-(2 -nitrobenzoyl)isatin, and its reduction afforded 53 (756). Bergman et al. 126,153) have developed a simple method heating of isatin, isatoic anhydride, and diisopropyl carbodiimide in pyridine with A-meth-ylpiperidine as catalyst afforded 53 in high yield. For information on other... 

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