Carbodiimides acid chlorides

AT-Acyl-L-HSL can be conveniently prepared in excellent yields by the acylation of l-HSL either with the corresponding carboxylic acids activated with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) in a water/ 1,4-dioxane (1 1) solvent system or with the corresponding acid chlorides in dichloromethane (DCM) in the presence of triethylamine (Scheme 4) [15,16, 37,53]. 

ROMP polymers bearing acid chloride, phosphonate, carbodiimide, phosphonyl chloride, and phosphine groups have been used as platforms in phase-switching, sequestration, capture-release, and soluble support applications. 

Biguanides [H2NC( = NH)NHC( = NH)NH2] react with lactones, amides, ortho esters, esters, acid anhydrides and acid chlorides to produce a wide range of 6-substituted 2,4-diamino-1,3,5-triazines (515) (59HC(l3)i). Biguanides with carbodiimides, isothiocyanates and ketones give corresponding melamines, thiones and dihydro derivatives, respectively. 

Nitrobenzoic acid chloride can be coupled to peptides in excellent yield, followed by reduction of the nitro function to the amine using either catalytic (Pd or Pt) hydrogenation t34,44-46 or tin(II) chloride. 33 This latter procedure has been applied to the solid phase. 41,42 A carbodiimide/HOBt coupling methodology has also been reported. 34 ... 

The reaction of 42 with 43 was attempted with dicyciohexylcarbodiimide (DCC) or water-soluble carbodiimide in solvent systems. All these reactions seemed to be unsuccessful because of the low solubility and low reactivity of 43. Among the methods of activation of a carboxy group, only the activated ester method of p-nitrophenyl ester was successful. In the acid chloride method a side reaction with the amino group of adenine was reported56. ... 

Benzyl and p-nitrobenzyl esters are usually made by classical methods such as reaction of benzyl alcohol with an acid chloride in the presence of pyridine or with a carboxylic acid in the presence of a carbodiimide (see general esterification methods). We have already shown the conversion of the cesium salt of a carboxylic acid to its benzyl ester by reaction with benzyl bromide [Scheme 6.40] ... 

Carboxylic acid chlorides react with carbodiimides to give N-acychloroformamidines 702. Further reaction of the N-acylchloroformamidines with tfaiosemicarbazide affords... 

Several types of additives have been found which reduce or eliminate the effects of various catalysts in polyurethane formation. When the catalyst is a simple base, an acid or acid precursor such as an acid chloride will reduce the rate of reaction due to neutralization of the basic catalyst. This is often most desirable, since many of the bases stronger than tertiary amines promote side reactions such as trimerization, carbodiimide formation and allophanate formation. The beneficial effect of acid retarders in a variety of systems was illustrated by Heiss et al. [151], as well as by others. 

Based on isoquinoline methiodide, I from the acid chloride, II from the acid plus carbodiimide. 

Scheme 12.1 Synthesis of ferrocenoyl amino acid esters (4) via the acid chloride and active ester methods (i) PCI5 or SOCI2 (ii) carbodiimide such as DCC (N Ji -dicy clohexy lcarbodiimide) or EDC (1 -ethyl-3-(3-dimethyl-aminopropyl)carbodiimide), HOBt (1-hydroxybenzotriazole) (iii) and (iv) peptide or amino acid and base.

For use in plastics, this might require chain extension with diisocyanates, bisoxazolines, carbodiimides, bis(an-hydrides), and such. One use of the oligomers would be to form polyurethanes by reaction with isocyanates. The use of acid chlorides can be avoided if the polymers are made by ester exchange or made enzymatically, with compounds such as divinyl adipate. Poly(butylene sebacate) with a molecular weight of 46,400 has been made has been made from bis(2,2,2-trifluoroethyl)sebacate and 1,4-butane diol.150 One polyester with a molecular weight of 24,000 has been made by ester exchange from isosorbide and a... 

Carboxylic acids can be attached to these linkers using methods of ester bond formation such as carbodiimide/DMAP [23] and acid chloride/base. For the loading of N-protected-a-amino acids in particular, an array of different methods has been developed to minimize enantiomerizahon and dipeptide formation during the esterification reaction. These include the use of MSNT/N-methylimidazole [24], mixed anhydrides generated with 2,6-dichlorobenzoyl chloride [25], esters of 2,5-diphenyl-2,3-dihydro-3-oxo-4-hydroxythiophene [26] and acid fluorides [27]. Phenols and N-protected hydroxylamines have been immobilized using the Mitsunobu reaction [28, 29], The latter are particularly useful for the preparation of hydroxamates [29, 30],... 

Amidation reactions are some of the most widely utilized in organic chemistry however, several of the commonly used amidation conditions are not suitable for large-scale manufacture. For instance, the use of carbodiimides poses a problem in that the reagents are potent sensitizers and the by-product ureas are not easily removable by nonchromatographic methods. Several other activation conditions such as formation of acid chlorides followed by amidation were explored in the laboratory and met with moderate success at best. Activation of 9 with iso-butyl chloroformate gave the desired mixed carbonic anhydride (Scheme 4.4), but subsequent reaction of the amine 8 occurred at the carbonate center to afford 9 and the isobutyl carbamate of 8 (via pathway b ), instead of amide 4 (pathway a ). 

Figure 14-1 Functionalization and activation of electrode materials, a) silanization of supports bearing hydroxylic groups b) reaction with cyanuric chloride c) activation with cyanogen bromide d) binding via amide bonds after activation with 1,1-carbonyldiimidazole e) activation with good leaving groups such as tresyl chloride f) formation of Schiff bases between aldehyde groups on the support and amino groups at the biomolecule g) activation of carboxylic groups with carbodiimides or h) via the acid chlorides.

Primary cycloaliphatic amines react with phosgene to form isocyanates. Reaction of isocyanates with primary and secondary amines forms ureas. Dehydration of ureas or dehydrosulfiirization of thioureas results in carbodiimides. The nudeophihcity that determines rapid amine reactivity with acid chlorides and isocyanates also promotes epoxide ting opening to form hydroxyalkji- and dihydroxyalkjiamines. Michael addition to acrylonitrQe yields stable cyanoethylcycloalkylamines. 

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