1H-indole-based chemosensors for the sequential recognition of Hg2+ and CN− ions

Divergent Diazo Approach toward Alkyl 5/4-Hydroxy-3H-benzo[e]indole-4/5-carboxylates

A divergent diazo approach toward alkyl 5/4-hydroxy-3H-benzo[e]indole-4/5-carboxylates has been developed. The reaction of 1,3-diketones with alkyl 2-diazo-3-oxo-3-(2H-azirin-2-yl)propanoates catalyzed by Co(acac)3 or Ni(acac)2 gives various alkyl 3-(1H-pyrrol-2-yl)-2-diazo-3-oxopropanoate in good yields. The latter undergo Wolff rearrangement followed by the 6π-cyclization of transient ketene to form alkyl 5-hydroxy-3H-benzo[e]indole-4-carboxylates bearing various substituents in positions 1, 2, 7, and 8, as well as derivatives of methyl 4-hydroxy-6H-thieno[2,3-e]indole-5-carboxylates and methyl 5-hydroxy-7H-benzo[c]carbazole-6-carboxylate under thermolysis or Rh2(OAc)4 catalysis. Isomeric benzoindoles, alkyl 4-hydroxy-3H-benzo[e]indole-5-carboxylates, have been prepared by Boc-protection of the pyrrole nitrogen of alkyl 3-(1H-pyrrol-2-yl)-2-diazo-3-oxopropanoates followed by an intramolecular formal carbene insertion into the aromatic C-H bond catalyzed by Cu(OTf)2. The hydroxyl group of alkyl 5/4-hydroxy-3H-benzo[e]indole-4/5-carboxylates, through the formation of the corresponding triflates, allows the introduction of various substituents into the 5/4 position of benzo[e]indoles using the cross-coupling reaction and even form a new heterocyclic backbone, benzo[k]pyrrolo[2,3-i]phenanthridine, via a tandem Suzuki reaction/nucleophilic acyl substitution.

New Bioactive Aromatic Heterocyclic Macromolecules with Monosaccharide Core

1,1,2-trimethyl-1H-benzo[e]indole is an important heterocyclic compound, its available in reasonable price and can easily modified to make a good intermediate for other derivatives. That is quite enough reasons to use as starting material for a new series of compounds with other biomolecules such as monosaccharides after simple modification. The target molecules show biological activity. So, the current work is aiming to improve the activity and the properties of the benzo indole by attaching with a naturally occurring, and biodegradable compounds represented by 2-deoxy-2-amino -d-glucose and 6-deoxy-6-amino-d-glucose to synthesis both mono and di-saccharides derivatives of benzo indole. Two steps synthesis were used for mono-saccharide derivatives and three steps for di-saccharide derivatives, the first is the functionalization of 1,1,2-trimethyl-1H-benzo[e]indole [1] via the reaction with POCl3 to produce 2-(1,1-dimethyl-1H-benzo[e]indol-2(3H)-ylidene) malonaldehyde [2] with two aldehydes reaction centers, while in the second step the latter was coupled with sugar via amino groups to get the two monosaccharide derivatives [3,5], while the disaccharides molecules [4,6] taken one more step with harder conditions to overcome the steric hindrance at the other reaction center. The purity and characterization of the target molecules was confirmed using spectroscopy methods including 1H NMR and 13 NMR. The synthesized compound shows a good biological activity as antibacterial antifungal.