Carbonyldiimidazole: Difference between revisions

| verifiedrevid = 396308758

| Name = Carbonyldiimidazole

| ImageFile = Carbonyldiimidazole.png

| ImageSize = 200px

| ImageName =

| ImageFile1 = Carbonyldiimidazole_3D.png

| ImageSize1 = 180px

| IUPACName = 1,1'-carbonyldiimidazole

| OtherNames = N,N'-carbonyldiimidazole<br />CDI

| Section1 = {{Chembox Identifiers

| SMILES = O=C(n1cncc1)n2ccnc2

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| Section2 = {{Chembox Properties

| C=7|H=6|N=4|O=1

| Appearance = White fine powder

| Density =

| Solubility = Reacts with water

| MeltingPtC = 119

| BoilingPt =

| Section3 = {{Chembox Structure

| CrystalStruct =

| Dipole =

| Section7 = {{Chembox Hazards

| ExternalMSDS = [http://physchem.ox.ac.uk/MSDS/CA/1,1'-carbonyldiimidazole.html External MSDS]

| MainHazards = Corrosive

| Section8 = {{Chembox Related

| Function =

| OtherFunctn =

| OtherCpds = [[phosgene]], [[imidazole]]

In this conversion, the imidazole serves both as the nucleophile and the base. An alternative precursor 1-(trimethylsilyl)imidazole requires more preparative effort with no corresponding advantages.

The purity of CDI can be determined by the amount of CO₂ that is formed upon hydrolysis (since the gas is formed essentially on a 1:1 molar ratio).<ref name="eeros">{{cite journal | author=A. Armstrong | title=N,N'-Carbonyldiimidazole | journal=Encyclopedia of Reagents for Organic Synthesis | year=2001 | doi=10.1002/047084289X.rc024 }}</ref>

CDI is mainly employed to convert alcohols and amines into [[carbamate]]s, esters, and [[urea]]s.<ref name="staab1" />

:[[Image:CDIgenrxn.png|400px|General reaction scheme]]

One common extension of this scheme lies in the transacylation reaction of acids that is promoted by CDI. Although the reactivity of CDI is less than [[acid chloride]]s, it is more easily handled and its reactions have a wider scope in synthesis.<ref name="eeros" /> An early application of this type of reaction was noted in the formation of imidazole peptide (and in general carboxylic acid) derivatives (with CO₂ formation as a driving force).

:[[Image:CDIacid.png|400px|Carboxylic acid reaction scheme]]

In the realm of peptide synthesis, this product may be treated with an amino acid or peptide ester (or amino acid hydrochloride in water) to release the imidazole group and couple the peptides. The side products, carbon dioxide and imidazole, are relatively innocuous.<ref>{{cite journal | author=R. Paul and G. W. Anderson | title=N,N'-Carbonyldiimidazole, a New Peptide Forming Reagent' | journal=Journal of the American Chemical Society | volume=82 | year=1960 | pages=4596–4600 | doi=10.1021/ja01502a038 | issue=17}}</ref> Racemization of the [[amino acid]]s also tends to be minimal, due to mild reaction conditions.

CDI can also be used for [[esterification]], although alcoholysis requires heat or the presence of a potent nucleophiles as sodium ethoxide,<ref name="staab1" /><ref name="eeros" />) and other strong bases like NaH. This reaction has generally good yield and wide scope (though forming the ester from tertiary alcohols when the acid reagent has a relatively acidic α-proton is troublesome, since [[claisen condensation|C-C condensations]] can occur, though this itself may be a desirable reaction).<ref name="staab1" /> A similar reaction involving [[thiol]]s and [[selenol]]s can yield the corresponding esters.<ref>{{cite journal | author=H.-J. Gais | title=Synthesis of Thiol and Selenol Esters from Carboxylic Acids and Thiols or Selenols, Respectively | journal=Angewandte Chemie International Edition in English | volume=16 | year=1977 | pages=244–246 | doi=10.1002/anie.197702441 | issue=4 }}</ref> The alcohol reaction can be used to form glycosidic bonds, as well.<ref>{{cite journal | author=M.J. Ford and S.V. Ley | title=A Simple, One-Pot, Glycosidation Procedure via (1-Imidazolylcaronyl) Glycosides and Zinc Bromide | journal=Synlett | volume=1990 |year=1990|pages=255–256 | doi=10.1055/s-1990-21053 | issue=05}}</ref>

Similarly, an acid can be used in the place of an alcohol to form the [[anhydride]]. The [[chemical equilibrium|equilibrium]] is best shifted in the favor of the anhydride by utilizing an acid in a 2:1 ratio that forms an insoluble salt with the imidazole, such as trifluoro- or [[trichloroacetic acid]] (and thus removes the free imidazole from the reaction). Symmetric anhydrides can thus be formed by replacing this trifluoro- or trichloroacetyl group with the acid that was used to form the original reagent.

::(C₆H₅)₃P=CHR + R'-CO-Im → (C₆H₅)₃P⁺-CHR-COR' + Im^-<br />(C₆H₅)₃P⁺-CHR-COR' + (C₆H₅)₃P=CHR → (C₆H₅)₃P=CR-COR' + (C₆H₅)₃P⁺-CH₂R

A C-C acylation reaction can occur with a [[malonic ester]]-type compound, in the following scheme useful for syntheses of macrolide antibiotics.<ref>{{cite journal | author=D.W. Brooks, et al. | title=C-Acylation under Virtually Neutral Conditions | journal=Angewandte Chemie International Edition in English | volume=18 | year=1979 | pages=72–74 | doi=10.1002/anie.197900722 }}</ref>

The N-phenylimino derivative of CDI can be formed in a Wittig-like reaction.<ref name="staab1" />

:[[Image:CDInderiv.png|400px|Formation of N-phenylimino derivative]]

CDI can act as a carbonyl equivalent in the formation of tetronic acids or pulvinones from hydroxyketones and diketones in basic conditions.<ref>{{cite journal | author=P.J. Jerris, et al. | title=A Facile Synthesis of Simple Tetronic Acids And Pulvinones | journal=Tetrahedron Letters | volume=47 | year=1979 | pages=4517–4520 | doi=10.1016/S0040-4039(01)86637-5 | issue=47 }}</ref>

An alcohol treated with at least 3 equivalents of an activated halide (such as allyl bromide or iodomethane) and CDI yields the corresponding bromide with good yield. Bromination and iodination work best, though this reaction does not preserve the [[stereochemistry]] of the alcohol. In a similar context, CDI is often used in dehydration reactions.<ref name="eeros" />

[[de:Carbonyldiimidazol]]

[[es:1,1-carbonildiimidazol]]

[[nl:Carbonyldiimidazool]]

[[ja:カルボニルジイミダゾール]]