Synthesis of diazocyclopentadiene

Preparation of diazocyclopentadiene

Preparation of diazocyclopentadiene

Preparation of diazocyclopentadiene

0.5 mole of phenyllithium prepared from 14 g. of lithium metal and 78 g. of bromobenzene is filtered by forcing through a tube containing glass wool by means of pressure from a tank of pre-purified nitrogen. The obtained phenyllithium solution is cooled and of  a  solution of 33 g. of freshly distilled cyclopentadiene in 150 ml. of dry ether was added dropwise with stirring over a period of 30 min.  After being stirred another hour at room temperature, the suspension of cyclopentadienyllithium is forced  under nitrogen pressure in a slow, steady stream into a cooled, stirred solution of 100 g. of p-toluenesulfonyl azide in 300 ml. of dry ether. The reaction became deep yellow almost immediately and gradually turned reddish-brown. A precipitate appeared during the addition which required one hours. Rapid filtration separated the mixture into a solid phase and a red ether solution which was extracted several times twice with 100-ml. portions of water, dried over anhydrous sodium sulfate and concentrated. Distillation of the residue through a short Vigreux column yields 16 g. (35% of  theory) of red diazocyclopentadiene, b.p. 52-53°C at 50 mm. Diazocyclopentadiene is purified by crystallization first from alcohol and then from pentane, both at -70°C. The heavy yellow needles melted at -23 to -22°C to a red liquid, n25/D=1.6150 (at 25°C), d29/25=1.059.

W. von E. Doering and C. H. DePuy, J. Am. Chem. Soc., 75, 5955 (1953).

IUPAC Name

5-diazocyclopenta-1,3-diene

InChI

InChI=1S/C5H4N2/c6-7-5-3-1-2-4-5/h1-4H

InChI Key

UETCMNDFHMOYSP-UHFFFAOYSA-N

Canonical SMILES

C1=CC(=[N+]=[N-])C=C1

Depositor-Supplied Synonyms

5-Diazo-1,3-cyclopentadiene, 1,3-Cyclopentadiene,5-diazo-, 1192-27-4, Diazocyclopentadiene, Cyclopentadiene, 5-diazo-, 5-diazocyclopenta-1,3-diene, AC1L39L8, 1,3-Cyclopentadiene, 5-diazo-, UETCMNDFHMOYSP-UHFFFAOYSA-N, OR109720

Removed Synonyms

CID136928

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