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rdf:type
lifeskim:mentions
pubmed:issue
Pt 6
pubmed:dateCreated
2010-11-24
pubmed:abstractText
The structures of reaction intermediates, arylnitrenes and their final products have been successfully analyzed by X-rays using acid-base complex formation. The acid-base complexes of 2-azidobenzoic acid (2a), 3-azidobenzoic acid (3a) and 4-azidobenzoic acid (4a) were made with dibenzylamine (db), N-benzyl-2-phenylethylamine (bp) and dicyclohexylamine (dc). For the complex crystals of (3a) and db (3a-db), and (4a) and db (4a-db) two forms of (I) and (II) were obtained. Eight types of complex crystals, (2a-db), (3a-db-I), (3a-db-II), (3a-dc), (4a-db-I), (4a-db-II), (4a-bp) and (4a-dc), suitable for X-ray analysis were obtained. When the crystals were irradiated with UV light at low temperatures, the reactions proceeded keeping the single-crystal form in the five crystals (2a-db), (3a-db-I), (3a-db-II), (3a-dc) and (4a-bp). Less than 25% of each azidobenzoic acids was transformed into an arylnitrene and dinitrogen. In three crystals the arylnitrenes produced gave new final products; 2,1-benzisoxazolone was observed for (2a-db) and trans-azobenzenes (i.e. dimerized nitrenes) were obtained for (3a-db-II) and (4a-bp). For (3a-db-I) and (3a-dc) the intermediate arylnitrenes were observed but did not transform to new products. All the structural changes were directly observed by X-ray analysis because the incomplete reactions occurred with retention crystallinity. The crystal environment, including the hydrogen bonding between the benzoic acid and the amine, places restrictions on the movement of the arylnitrene and influences the reaction pathway followed for conversion of the arylnitrene to its final product.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Dec
pubmed:issn
1600-5740
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
66
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
647-61
pubmed:year
2010
pubmed:articleTitle
Direct observation of various reaction pathways of arylnitrenes in different crystal environments caused by acid-base complex formation.
pubmed:affiliation
Department of Chemistry and Materials Science, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8551, Japan.
pubmed:publicationType
Journal Article