Of phenanthridines

The former passes into the second on further oxidation with hydrogen peroxide, indicating that it is an a-keto-carboxylic acid. Acid (b) loses carbon dioxide on fusion and gives a neutral substance, CjaHj OgN, m.p. 238°, which was shown to be 6 7-methylenedioxy-A-methylphenanthri-done (I), by comparison with a synthetic specimen. The position of the carboxyl group in (b) could not be determined by synthetic methods but is probably at since dihydrolycorineanhydromethine, Cl 7 7 2 ) m.p. 87-5° [picrate, m.p. 174° (dec.) methiodide, m.p. 236° (dec.)] on distillation with zinc dust yields a mixture of phenanthridine, 1-methyl-phenanthridine and 6 7-methylenedioxyphenanthridine, m.p. 142° [picrate, m.p. 257° (dec.)], the identity of the two latter being established by comparison with the synthetic products. These results indicate for lycorineanhydromethine formula (II). 

The Pictet-Hubert reaction has found utility in the production of phenanthridine molecules that act as DNA-intercalator antitumor and antiviral agents (17). 

It would be expected that the stabilization of the adsorbed species by an extended conjugated system should increase with the number of aromatic rings in the adsorbed azahydrocarbon. However, data suitable for comparison are available only for phenanthridine, benzo-[/]quinoline, and benzo[h] quinoline. The large difference in the yields of biaryl obtained from the last two bases could be caused by steric interaction of the 7,8-benz-ring with the catalyst, which would lower the concentration of the adsorbed species relative to that with benzo[/]quinoline. The failure of phenanthridine to yield any biaryl is also noteworthy since some 5,6-dihydrophenanthridine was formed. This suggests that adsorption on the catalyst via the nitrogen atom is possible, but that steric inhibition to the combination of the activated species is involved. The same effect could be responsible for the exclusive formation of 5,5 -disubstituted 2,2 -dipyridines from 3-substi-tuted pyridines, as well as for the low yields of 3,3, 5,5 -tetramethyl-2,2 -bipyridines obtained from 3,5-lutidine and of 3,3 -dimethyl-2,2 -... 

Thermolysis of 2,2 -bis(azidomethyl)biphenyl (33) in an inert solvent produces a mixture of phenanthridine (21 %) and 5//-dibenz[c,e]azepine (29% bp 138—140°C/0.08 Torr). The yield of dibenzazepine is increased to 57% by carrying out the thermolysis under reduced pressure over glass beads.86 The mechanism of this unique reaction has been discussed. 

Irradiation of phenanthridine 5-oxides gives complex mixtures containing dibenzoxazepines. The reaction is solvent dependent. In benzene, for example, 6-phenylphenanthridine 5-oxide affords the dibenzoxazepine 4a (26%), 6-phenylphenanthridine (12%), 5-phenylphenanthrid-6(5//)-one (19%) and (V-benzoyl-2-(2-hydroxyphenyl)aniline (7%).27... 

Reaction of Ar-Benzenesulfonyl-3-[bis(methyIthio)methyIenel-2r3-dihydro-l/F-quinoline-4-one 6.36 with Allyl and Benzyl Anions A New Regiospecific Synthesis of Phenanthridines and Benzo[/]phenanthridines... 

The reaction of 6.36 with allyl and benzyl anions was examined with a view to develop an efficient method for the synthesis of phenanthridines and their benzo[/]-derivatives. The dithioacetal 6.36 when reacted with allyl anions yielded the corresponding... 

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... 

A tetracyclic p-lactam 82 was formed in an attempted deprotection of 81 using lead tetraacetate <99T8457>. Other tetracyclic p-lactams (e.g. 83) have been obtained by ketene addition to the C9-N10 bond of phenanthridine <98TL7431,99TL2005>. 

Whereas treatment of phenanthridine with AT-bromosuccinimide gives only 2-bromo-phenanthridine, use of bromine and silver sulfate in 92% sulfuric acid gives, in low yields, 10-, 4- and 1-bromo-phenanthridines in the ratio 9.5 6.4 1 together with some dibromo products (Scheme 11) (69AJC1105). This order of reactivity contrasts with that observed for nitration of phenanthridine (Section 2.06.2.1.2). 

Ozonolysis of phenanthridine in methylene chloride followed by alkaline peroxide oxidation gives quinoline-3,4-dicarboxylic acid (2%) and phenanthridone (39 23%) as the main product (Scheme 27) (64JA38). 

The hydrogenation of phenanthridine at 250 °C under pressure in the presence of a sodium-rubidium catalyst in benzene is reported to give octahydrophenanthridines. Acridine similarly forms a variety of reduction products (71JOC694). 

Pyrolysis of anils has long been known to give polycycles, as shown by the synthesis of phenanthridine (120) (1889CB3340) and of the two benzophenanthridines (121) and (122) <1891LA(266)155>. More recently, quinoline has been obtained by flash vacuum pyrolysis of the dianil (123) <80JCS(P1)2200). 

A very large group of syntheses in which the /3,y-bond is formed are those in which a side chain electrophile attacks the benzene ring. These include the Skraup and Doebner-von Miller syntheses (dealt with in Section 2.08.2.2.3(ii)), the Knorr, Conrad-Limpach and Combes syntheses of quinolines (dealt with here), the Pomerantz-Fritsch synthesis of isoquinolines, and many syntheses of phenanthridines and of acridines. 

The cyclic borates (758) are useful alternatives to benzanilides in the photochemical synthesis of phenanthridines. Irradiation, followed by reduction with lithium aluminum hydride, gives phenanthridines in good yield, the borate ring maintaining the correct stereochemistry (78CC884). 

Methyl substituents can have unusual effects on the reactivity of phenanthridine (21). In keeping with an electron-donating effect, the introduction of a methyl group at position 3 or 8 gives rise to a small, normal, rate acceleration in reactions with Mel. By contrast, a methyl group at position 1 or 10 produces a decrease in the rate constant for N-methylation, and methyl groups at both the 1 and 10 positions together... 

Trypanocidal activity of phenanthridine derivatives was discovered in 1938 when phenidium (71) was tested versus T. congolense in mice. Dimidium (72) was quickly found more efficacious when both compounds were introduced for field use. However, for cattle, dimidium (72) is a relatively toxic substance. The discovery that homidium (73) is 10 to 50 times more potent as a trypanocide as well as less toxic to the host led to its introduction and continued use at a dose level of 1 mg kg-1. 

As shown in Table 1, an increase in the concentration of phenanthridine leads to a decrease in the rate of styrene oxide transformation. 

Although the amount of phenanthridine is ten and twenty times that of the amount necessary to cover the total external surface of the zeolite, it must be noted that the reaction always takes place. 

Mol. wt. 181-233, m.p. 124°. The reagent is prepared by reduction of phenanthridine with lithium aluminum hydride in refluxing ether (75% yield).1... 

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