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Synthesis of 4-aryloxy-7-nitrobenzofurazan derivatives from 4-chloro-7-nitrobenzofurazan and various phenoxide anions (including pharmaceuticals) in the presence of crown ethers

100%

Bem M., Caproiu M., Stoicescu D., Constantinescu T., Balaban A.

Open Chemistry

2003

vol. 1

issue 3

260-276

4-Chloro-7-nitrobenzofurazan reacts by nucleophilic substitution with phenoxide anions derived from estriol (2c), ethynylestradiol (2d), phenol (3e), guaiacol (3f), 2,6-dimethoxyphenol (3g), eugenol (3h), isoeugenol (3i), the cytostatic Etoposide (4), and Reichardt’s betaine (5) in the presence of crown ethers affording the corresponding 4-aryloxy-7-nitrobenzofurazan derivatives 6c, 6d, 7e-7i, 8, and 9. The structure of these compounds was confirmed by NMR spectra. Hydrophobicity/hydrophilicity parameters were investigated by reverse phase thin-layer chromatography.

Structural factors influencing the reaction rates of 4-aryloxy-7-nitrobenzofurazans with amino acids

73%

Bem M., Vasilescu M., Caproiu M., Draghici C., Beteringhe A., Constantinescu T., Banciu M., Balaban A.

Open Chemistry

2004

vol. 2

issue 4

672-685

An interesting observation was made when studying the SNAr reaction between several 4-aryloxy-7-nitrobenzofurazans (2) and several amino acids leading to the apparition of detectable fluorescence from the substitution products3. Acidic amino acids reacted very slowly=while basic amino acids react fastest with2 having an unsubstituted phenyl or a 4-formyl-phenyl Ar group. Amongst neutral amino acids, proline reacts fastest at room temperature after 100 min. With2 having a methoxy-subtituted Ar group.

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2 Open Chemistry

1 2004

1 2003

2 Balaban A.

2 Bem M.

2 Caproiu M.

2 Constantinescu T.

1 Banciu M.

1 Beteringhe A.

1 Draghici C.

1 Stoicescu D.

1 Vasilescu M.

Search results

Synthesis of 4-aryloxy-7-nitrobenzofurazan derivatives from 4-chloro-7-nitrobenzofurazan and various phenoxide anions (including pharmaceuticals) in the presence of crown ethers

Structural factors influencing the reaction rates of 4-aryloxy-7-nitrobenzofurazans with amino acids