Functionalization of quinoxalines by using TMP bases: preparation of tetracyclic heterocycles with high photoluminescene quantum yields.
Chemistry
; 21(3): 1102-7, 2015 Jan 12.
Article
em En
| MEDLINE
| ID: mdl-25404387
ABSTRACT
Tetracyclic heterocycles that exhibit high photoluminescence quantum yields were synthesized by anellation reactions of mono-, di-, and trifunctionalized 2,3-dichloroquinoxalines. Thus, treatment of 2,3-dichloroquinoxaline with TMPLi (TMP = 2,2,6,6-tetramethylpiperidyl) allows a regioselective lithiation in position 5. Quenching with various electrophiles (iodine, (BrCl2 C)2 , allylic bromide, acid chloride, aryl iodide) leads to 5-functionalized 2,3-dichloroquinoxalines. Further functionalization in positions 6 and 8 can be achieved by using TMPLi or TMPMgClâ
LiCl furnishing a range of new di- and tri-functionalized 2,3-dichloroquinoxalines. The chlorine atoms are readily substituted by anellation with 1,2-diphenols or 1,2-dithiophenols leading to a series of new tetracyclic compounds. These materials exhibit strong, tunable optical absorption and emission in the blue and green spectral region. The substituted O-heterocyclic compounds exhibit particularly high photoluminescence quantum yields of up to 90%, which renders them interesting candidates for fluorescence imaging applications.
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Base de dados:
MEDLINE
Assunto principal:
Quinoxalinas
/
Compostos Heterocíclicos
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article