Phenanthridine, 6-phenyl

Phenanthridine (74) was converted by NBS into the 2-bromo derivative (40%) (55JA6379), but the bromine-sulfuric acid-silver sulfate reagent gave low yields of 1-, 4-, and 10-bromophenanthridines in the ratio (1 6.4 9.5), a reactivity order which contrasts with that found in nitration (1 > 10 > 4 > 2) (69AJC1105). Phosphoryl chloride converted phenanthridine 5-oxide into the 6-chloro derivative, but when that position was blocked by a phenyl substituent, the reductive chlorination process gave a 2-chloro compound (84MI2). 

Thus, the phenanthridine-fused benzaldehyde triazinylhydrazone 229 was cyclized by using thionyl chloride to the phenyl substituted pentacyclic product 230 <1998NN1385>. The corresponding methyl-substituted fused system... 

Intramolecular cyclization of 2-lithiobenzyl-2-halophenyl amines, ethers, and thioethers—Synthesis of phenanthridine, dibenzopyran, and dibenzothiopyran derivatives Having demonstrated the efficiency of this methodology for the preparation of indole derivatives, we prepared the 2-fluoro-phenyl ether and thioether 22 a, b to study their potential as substrates that could afford oxygen and sulfur heterocycles. However, treatment of 22 a, b with fBuLi afforded, after... 

Several reactions involving benzyne intermediates have been employed in the synthesis of phenanthridines. Benzyne itself reacts with phenyl isocyanate to give phenanthridone, probably via the Diels-Alder adduct (157). A second product is 6-phenoxyphenanthri-... 

Several acetylenic esters have been shown to react with phenan-thridine-5-oxide (or its 6-alkyl derivatives) forming adducts of the type (21 5).308 Under necessarily more vigorous conditions (in di-methylformamide at 100°) the less reactive methyl phenylpropiolate combined with 6-methylphenanthridine-5-oxide to form 2-phenyl-pyrrolo[l,2-/]phenanthridine-3-carboxylate (216) directly, presumably via an intermediate of type (215).285... 

The suggestion5 that phenanthridine can probably be alkylated directly under suitably vigorous Friedel-Crafts conditions does not appear to have been tested experimentally. It receives support, however, from the successful conversion of the quaternary salts (220) (R1 = Me, R2 = H) and (220) (R1 = H, R2 = Ph) into the corresponding 221 by heating with polyphosphoric acid.287 Not surprisingly, however, the related salt (220) (R1 = H, R2 = m-methoxy-phenyl) forms 222 under similar conditions.17 Direct alkylation of phenanthridine has been achieved photochemically (see p. 400). 

Aminative replacement in compounds other than those bearing halogen atoms are uncommon, but 6-aminophenanthridine is easily prepared by heating 6-phenoxyphenanthridine with urea296 and 6-anilinophenanthridine has been obtained by the action of aniline on the 6-phenoxy compound.268 The formation of 6-anilinophenanthridine from phenanthridine iV-oxide and phenyl isocyanate probably proceeds via an initial 1,3-dipolar addition, followed by nucleophilic substitution and decarboxylation (Scheme 4).309... 

The known reactivity of phenanthridine towards lithium aryls extends to the hindered o-tolyllithium, where the stability of the 6-o-tolyl-5,6-dihydrophenanthridine allows its isolation.314 (6-Phenyl-phenanthridine forms 6,6-diphenyl-5,6-dihydrophenanthridine under similar conditions.62,314)p-Biphenylyllithium reacts smoothly to give the dihydro adduct oxidation in situ with boiling nitrobenzene gives the 6-biphenylylphenanthridine in good yield.327... 

Electroreduction of l-(4-fluorophenyl)-5-(2-halogenophenyl)tetrazoles (89), when the halogen substituent is Cl, Br or I, leads to cleavage of the carbon-halogen bond to give a phenyl radical (equation 52). Competition then follows between intramolecular radical substitution giving 7-fluorotetrazolo[l,5-f]phenanthridine (90). Further reduction of the... 

Related 1,3-oxazepines have been obtained from irradiation of many other heterocyclic A-oxides including pyridine A-oxides, isoquinoline A-oxides, quinoxaline A-oxides, quinazoline A-oxides, phenanthridine A-oxides, benzophenazine A-oxides, and acridine A-oxides.4 However, the reported yields are variable and have generally been higher for phenyl and other aryl-substituted derivatives. 

In some cases an intramolecular arylation (Section A.l.i, f, equations 85 and 107) is problematic. Cyclic Af-(2-bromophenylethylenaminones instead of benzazepines with LiNEt2 yield indolines. Photolysis seems to be a good alternative method. A photolytic reaction of the same reagents leads to the desired benzazepines in high yield204-207 (equation 146). Carbazoles and phenanthridines can also be obtained by photocycliza-tion of brominated N-phenyl, N-benzyl derivatives of cyclic enaminones in yields similar to those in the base promoted cyclization (see equations 84, 106 and 107). 

Octahydro-phenanthridin ist mit Raney-Nickel (2071 bar) aus 2-(2-Nitro-phenyl)-1-formyl-cyclohexan zuganglich6. 

On refluxing in hydrocarbon solvents with sodium or magnesium-magnesium iodide, phenanthridine forms a mixture of 6,6 -biphenan-thridyl, 5,6-dihydro-6,6 -biphenanthridyl, and 5,6-dihydrophenan-thridine. By the action of lithium in tetrahydrofuran 5,6-dihydro-phenanthridine and 5,5, 6,6 -tetrahydro-6,6 -biphenanthridyl were obtained. Chemical evidence in favor of 230 is provided by the fact that both 6-phenyl and 6-biphenylylphenanthridine give only the corresponding dihydro derivatives, with no trace of bimolecular reduction. ... 

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