Diethyl azodicarboxylate

Description

Our Halloween 2012 series begins with a molecule that has the acronym DEAD. It stands for diethyl azodicarboxylate, an orange–red liquid that becomes yellow when diluted in a solvent. DEAD is a strong electron acceptor; it oxidizes iodide to molecular iodine, hydrazine to molecular nitrogen, alcohols to aldehydes, and thiols to disulfides. DEAD’s principal use is as a reagent in the Mitsunobu condensation reaction, and it participates in Michael and Diels–Alder reactions. Because it explodes when heated, it cannot be shipped in pure form. Instead, it is transported in solution or adsorbed onto plastic particles.

Description

Diethyl azodicarboxylate (DEAD) is commonly used in Mitsunobu reactions. It is often used as a 40% solution in toluene. Similar reagents include DIAD, DtBAD, and ADDP.

Chemical properties

Clear orange to orange-red liquid

The Uses of Diethyl azodicarboxylate

A fluorescent CDK inhibitor for treatment of cancer

The Uses of Diethyl azodicarboxylate

To a solution of A (400 mg, 1.54 mmol), B (621 mg, 3.09 mmol), and PPh3 (610 mg, 2.32 mmol) in THF (5.5 mL) at RT was added DEAD (404 mg, 2.32 mmol) in THF (0.5 mL). After 90 min, silica gel was added and the mixture was concentrated and purified on a flash column (25% EtOAc/hexane) to provide the product. [545 mg, 80%]

The Uses of Diethyl azodicarboxylate

Reactant for preparation of:

• Immunostimulants α-Galactosylceramides
• Cellotriose and cellotetraose analogues as transition state mimics for mechanistic studies of cellulases
• Bisubstrate inhibitors with molecular recognition at the active site of catechol-O-methyltransferase
• Derivatives of F200 and S383 with cannabinoid CB1 receptor binding activities
• Aza-β-lactams via NHC-catalyzed [2 + 2] cycloaddition with ketenes

Reagent for:

• Annulation of N-protected imines
• α-thiocyanation of enolizable ketones with ammonium thiocyanate
• Diels-Alder reactions

General Description

DOT Special Approval Submission is Under Review. Availability is Estimated as March 2012.

Purification Methods

Dissolve DEAD in toluene, wash it with 10% NaHCO3 till neutral (may require several washes if too much hydrolysis had occurred: check IR for OH bands), then wash with H2O (2x), dry over Na2SO4, filter, evaporate the toluene and distil it through a short Vigreux column (p 11) at as high a vacuum as possible. The main portion boils at 107-111o/15mm. Since it is likely to explode, use an oil bath for heating the still and all operations should be carried -out behind an adequate shield. [Rabjohn Org Synth Coll Vol III 375 1955, see Kauer Org Synth Coll Vol IV 412 1963]. [Beilstein 3 III 233.] It is commercially available as a 40% solution in toluene. This reagent is useful in the Mitsunobu reaction [Mitsunobu Synthesis 1 1981, Gennari et al. J Am Chem Soc 108 6394 1986, Evans et al. J Am Chem Soc 108 6394 1986, Hughes Org React 42 335 1992, Dodge et al. Org Synth 73 110 1996, Hughes Org Prep Proc Int 28 127 1996, Ferguson & Marcelle J Am Chem Soc 128 4576 2006; see also di-tert-butyl azodicarboxylate above and DIAD below]. § A polystyrene supported DEAD version is commercially available with a loading of ~1.2mmol/g.