TITLE

Synthesis and reactivity of novel Schiff bases containing boronate esters

AUTHOR(S)
Norman, David W; Edwards, Janet P; Vogels, Christopher M; Decken, Andreas; Westcott, Stephen A
PUB. DATE
January 2002
SOURCE
Canadian Journal of Chemistry;Jan2002, Vol. 80 Issue 1, p31
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Condensation of 2-aminophenol with boronate ester derivatives of benzaldehyde afforded the corresponding boron-containing Schiff bases, 2-HOC[sub 6] H[sub 4] N=C(H)C[sub 6] H[sub 4] R (1a: R = 2-Bpin; 1b: R = 3-Bpin; 1c: R = 4-Bpin; pin = 1,2-O[sub 2] C[sub 2] Me[sub 4] ). Crystals of 1b were triclinic, space group P, a = 11.9420(6), b = 13.0871(7), and c = 13.2720(7) �, a = 70.983(1), � = 67.793(1), and ? = 78.380(1)�, Z = 2. Reaction of 2-aminophenol with 2-HC(O)C[sub 6] H[sub 4] B(OH)[sub 2] in EtOH, however, gave a macrocyclic dimer 2 with a OBOBO structural unit. The molecular structure of this dimer has been confirmed by an X-ray diffraction study. Crystals of 2 were monoclinic, space group P2[sub 1] /c, a = 10.0447(8), b = 21.0894(15), and c = 12.6214(9) �, � = 105.301(2)�, Z = 4. Further reaction of these Schiff bases with manganese triacetate in toluene afforded 2-arylbenzoxazoles 3a�c via an oxidative cyclization pathway. The molecular structure of the 4-Bpin derivative (3c) was characterized by an X-ray diffraction study. Crystals of 3c were monoclinic, space group P2[sub 1] /n, a = 6.5392(3), b = 16.3330(8), and c = 16.1942(8) �, � = 97.9620(10)�, Z = 4.Key words: boron heterocycles, Schiff bases, arylbenzoxazoles.La condensation du 2-aminoph�nol avec des d�riv�s boronates de benzald�hyde conduit � la formation des bases de Schiff correspondantes contenant du bore, 2-HOC[sub 6] H[sub 4] N=C(H)C[sub 6] H[sub 4] R (1a: R = 2-Bpin; 1b: R = 3-Bpin; 1c: R = 4-Bpin; pin = 1,2-O[sub 2] C[sub 2] Me[sub 4] ). Les cristaux du compos� 1b sont tricliniques, groupe d'espace P, avec a = 11,9420(6), b = 13,0871(7) et c = 13,2720(7) �, a = 70,983(1), � = 67,793(1) et ? = 78,380(1)� et Z = 2. La r�action du 2-aminoph�nol avec le 2-HC(O)C[sub 6] H[sub 4] B(OH)[sub 2] dans l'�thanol conduit toutefois � la formation du dim�re macrocyclique 2 qui comporte une unit� structurale OBOBO. La structure mol�culaire de ce dim�re a �t� confirm�e par diffraction des rayons X. Les cristaux du compos� 2 sont monocliniques, groupe d'espace P2[sub 1] /c, avec a = 10,0447(8), b = 21,0894(15) et c = 12,6214(9) �, � = 105,301(2)� et Z = 4. Des r�actions subs�quentes de ces bases de Schiff avec du triac�tate de mangan�se dans le tolu�ne conduisent � la formation des 2-arylbenzoxaoles (3a�c) par le biais d'une voie r�actionnelle de cyclisation oxydante. La structure mol�culaire du d�riv� 4-Bpin (3c) a �t� caract�ris�e par diffraction des rayons X. Les cristaux du compos� 3c sont monocliniques, groupe d'espace P2[sub 1] /n, avec a = 6,5392(3), b = 16,3330(8) et c = 16,1942(8) �, � = 97,9620(10)� et Z = 4.Mots cl�s : h�t�rocycles du bore, bases de Schiff, arylbenzoxazoles.[Traduit par la R�daction]
ACCESSION #
10580730

 

Related Articles

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics