Dibenzo xanthene

Methoxy-9 [4-iiitro-phen3i]-1.2 7.8-dibenzo-xanthen 17 II178. 

OaHaCljO Biohlorderivat des 9-Methyl. 9-n-hezyl-3.4 6.6.dibenzo-xanthens 17143. 

Diohlorderivat des 9-Methyl-9-phenyl-3.4 5.B-dibenzo-xanthens 17 I 47. CgiHuCIgOg Diehlordibenzoylstilben vom Schmelzpunkt 202° 7. 845. Dichlordibenzoylztilben vom Schmelzpunkt 230° 7, 845. 

Carbazole, A-methylcarbazole, IV-ethylcarbazole, dibenzofuran, dibenzothiophene, fluorene, dibenzo-p-dioxin, phenoxathiin, phenoxazine, phenothiazine, xanthene, biphenyl, naphthalene, phenanthrene, anthracene, and fluoranthene could be transformed by E. coli, [314] which was transformed using a plasmid bearing the carAa, Ac, and Ad genes, and expressing only the carA-encoded proteins. Further work is needed to develop a final biocatalyst and to prove the advantages that this degradative pathway would incorporate in a refining bioprocess. 

Dibenzofa, ejpyrans — see Xanthenes H-Dibenzo[a,g]quinolizine, 5,6,13,13a-tetrahydro-, 2, 547... 

Xanthene dyes are those containing the xanthylium [261-23-4] (la) or dibenzo-y-pryan nucleus [92-83-1] (xanthene) (lb) as the chromophore with amino or hydroxy groups meta to the oxygen as the usual auxochromes. They are... 

Phenanthren-9-ylmethyl)phenyl trifluoromethanesulfonate 164 undergoes a palladium-catalyzed cyclization via S-0 bond cleavage to afford 14/f-dibenzo[ ,f]xanthene in moderate yield (Equation 76) <2002T5927>. 

The acid-mediated condensation of 2-naphthol with aliphatic or aromatic aldehydes can proceed under solvent-free conditions or in dichloroethane to give 14-alkyl/aryl-14//-dibcnzo[tf1/]xanthenes 167 in excellent yield (Equation 78) <2005SL955>. Sulfamic acid can also effectively catalyze the condensation of 2-naphthol with aromatic aldehydes either at 125 °C or under microwave irradiation to yield 14-aryl-14//-dibenzo[tf,/]xanthcncs in high yield (92-96%) <2005TL8691>. 

Benzo[a] and benzo[c] xanthene and dibenzo[a,c]xanthene have been synthesised by the Pd-catalysed cyclisation of aromatic 2-(arylmethyl)phenol triflate esters through S-0 bond cleavage <02T5927>. 

Synthetic approaches to xanthenes (9//-dibenzo[A< ]pyrans) most commonly involve cyclizations creating new GO bonds (e.g., Scheme 33) <2002T5927> or new CG bonds (e.g., Scheme 34) <2001SC877, CHEC-III(7.08.7)467>. 

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