9,20-Dihydro-9- acridine

Intramolecular attack of the carbenes shown in Scheme 30a provides benzo[6]cyclo-hepta[(5 ]-furans and -thiophenes, but the nitrogen analogue (X = NH) yields 9,10-dihydro-acridine 81AJC1037). Photolysis of 2-biphenyl isocyanide (Scheme 30b) (72JOC3571) and thermolysis of 2-biphenylsulfonyl diazomethane (Scheme 30c) (72CC893) also result in ring expansion. 

Acridine, 9,10-dihydro-9,9-dimethyl-as antidepressant, 1, 169 Acridine, 9-formyl-synthesis, 2, 507 Acridine, 3-hydroxy-formylation, 2, 322 Acridine, 9-hydroxy-N-oxide... 

Benz[a]acridine-3,4-diol, 3,4-dihydro-oxidation, 2, 184-185 Benz[c]acridine-3,4-diol, 3,4-dihydro-oxidation, 2, 185 Benzacri dines synthesis... 

Like acridine, phenanthridine and dimethyl acetylenedicarboxylate in methanol give a high yield of 1 1 1 molar adduct. Ultraviolet absorption spectrum comparisons show that this is best formulated as 9,10-dihydro-9-methoxy-10- (tran.s-l,2-dimethoxycarbonylvinyl) phenanthridine (142) rather than the corresponding phenanthridinium methoxide (143) under neutral conditions acidification changes the spectrum to that characteristic of the phenanthridinium cation. Crystallization of the adduct (142) from methanol containing 5-15% of water gave the betaine [(144) the positions of the ester and carboxylate groups have not been established], while in the presence... 

A detailed study of the dehydrogenation of 10.1 l-dihydro-5//-benz[6,/]azcpinc (47) over metal oxides at 550 C revealed that cobalt(II) oxide, iron(III) oxide and manganese(III) oxide are effective catalysts (yields 30-40%), but formation of 5//-dibenz[7),/]azepinc (48) is accompanied by ring contraction of the dihydro compound to 9-methylacridine and acridine in 3-20 % yield.111 In contrast, tin(IV) oxide, zinc(II) oxide. chromium(III) oxide, cerium(IV) oxide and magnesium oxide arc less-effective catalysts (7-14% yield) but provide pure 5H-dibenz[b,/]azepine. On the basis of these results, optimum conditions (83 88% selectivity 94-98 % yield) for the formation of the dibenzazepine are proposed which employ a K2CO,/ Mn203/Sn02/Mg0 catalyst (1 7 3 10) at 550 C. 

CeHs iHz Xil LifAlFL,] Ather I2-Benzyl-7,12-dihydro-(benzo-[a]-acridin ) 75 138-140 H... 

Jod-phenyl)-acridin wird in waGrigem Athanol an Quecksilber bei —1,36 V na-hezu quantitativ in das 10-(2-Jod-phenyl)-9,10-dihydro-acridin (F 152-153°) iiberfuhrt (zur Weiterreduktion bei —1,7 V, s. S. 623)... 

Jod-phenyl)-9,10-dihydro-acridin wird nahezu quantitativ in das 9-Phenyl-9,10-dihydro-acridin iiberfiihrt (s. a. S. 593)8. 

Pyridazines continued to play a central role in the construction of new biologically active compounds. 2,7-Dihydro-3//-pyridazino 5,4,3-17 acridin-3-ones were synthesized as cytotoxic agents <05BMC1969> and 6-(5-chloro-3-methylbenzofuran-2-sulfonyl)-2//-... 

Tumorigenicity of tetrahydroepoxides. As yet, only Ch H -epoxide has been directly demonstrated to be tumorigenic (18). However, indirect evidence has been found in the high tumorigenicity of 3,4-dihydro BA, 9,10-dihydro BeP and 3,4-dihydrobenz[c]acridine (19-21), each of which is a likely metabolic precursor of a bay-region H -epoxide. In the case of 9,10-dihydro BeP, cis- and trans-9,10-dihydroxy -9,10,11,12-tetrahydro BeP were identified as products of metabolism of 9,10-dihydro BeP (22), and are the expected products of hydration of the epoxide. Diols are also formed from 7,8-dihydro BaP upon metabolism with prostaglandin endoperoxide synthase (23) or with rat liver homogenates (24). 

Under basic conditions, A -acridinylmethyl-substituted thiourea 449 placed in the presence of bromoacetonitrile gave rise to the unexpected formation of the spiro[dihydro-acridine-9(10//),2 -(2, 7 -dihydro-3 //-imidazo[l,2-c]thiazol-5 -ylidene-/>-nitrophenyl)amine] 450 in 67% yield. The reaction involved displacement of the bromine atom of... 

Products isolated from the thermal fragmentation of A-arylbenzamide oximes and A-arylbenzamide O-phenylsulfonyl oximes have been accounted for by invoking a free-radical mechanism which is initiated by the preferential homolysis of the N-O bond." Time-resolved IR spectroscopy has revealed that photolysis of A, A -diphenyl-l,5-dihydroxy-9,10-anthraquinone diimine affords acridine-condensed aromatic products via excited-state intramolecular proton transfer." The absolute and relative rates of thermal rearrangements of substituted benzyl isocyanides have been measured,and it has been found that the relative rates are independent of temperature and exhibit excellent Hammett correlations. Thionitrosoarene (25), thought to be generated by desulfurization of the stable A-thiosulfinylaniline (24), has been established" " as an intermediate in the formation of 3,3a-dihydro-2,l-benzisothiazole (26) from o-alkylthionitrosoarene (24). 

With acridine, owing to the greater difficulty of rearomatization, it was possible to obtain the 9-acyl-9,10-dihydro derivatives, particularly by using the redox system i-BuOOH/Ti +. 

This last path has experimental support in the case of the reaction with acridine in the isolation of 9-acyl-9,10-dihydro derivatives. This behavior can be correlated with the fact that the protonation of the heterocyclic nitrogen and the presence of an electron-withdrawing group (R-CO) causes a relatively high ionization potential of the o-complex... 

Aminoacridine derivatives reacted with formaldehyde in acidic medium to form (depending on the stoichiometry) various condensation products, among them 3,4-dihydro-l//-l,3-oxazino[4,5-f]acridines <1997X2891, 1998H(48)755, 2001J(P1)2962, 2006BML4641>. 

Oxidation of 5//-dibenz[6,/]azepines by Fremy s salt has been examined closely. At pH 7.5 the quinonoid dibenz[6,/]azepin-2-one is produced together with acridine-9-aldehyde (74CRV101). 3-Chloro-10,11 -dihydro-5//-dibenz[6,/]azepine yields a mixture of the quinoneimines (174 R=C1) and (175) which with sodium dithionite reduce to the corresponding chlorohydroxydihydrodibenzazepines (76JHC269). 

The interaction between pyridine and organolithium compounds in benzene was first reported by Ziegler and Zeiser129 and was attributed to the formation of 1 1 adducts. Indirect evidence for intermediates of this kind was based on the formation of dihydropyridines by treatment of the reaction mixture with water. More definite evidence was obtained with quinoline, isoquinoline, and acridine.130 Phenyllithium reacts quantitatively with quinoline in ether to yield an adduct as a yellow powder that can be recrystallized. In order to define the site of attachment, the adducts were hydrolyzed to dihydro derivatives and the latter dehydrogenated. Because this treatment leads mainly to 2-phenyIquinoIine and l-phenylisoquinoline from quinoline and isoquinoline, respectively, the related adducts can be assumed to have structures 80 and 81. Isolation and characterization of the dihydro derivatives have been carried out, as well as in the case of the reaction of acridine with phenyllithium. 

Acridone or 9(10H)-Acridone, called in Beil 9-O2D-9.10-dihydro-acridin,... 

Keywords acridine, diphenylacetic acid, photodecarboxylation, two-component molecular crystal, chiral crystal, 7,8-dihydro-7-diphenylmethyl-acridine... 

Chemical Name 7H-Pyrano[2,3-c]acridin-7-one, 3,12-dihydro-6-methoxy-3,3,12-trimethyl-... 

Treatment of 2-(l-naphthylaminomethylene)-l-tetralone (143) with formic acid provides 7,8-dihydro-3,4 9,10-dibenzophenanthri-dine (144),177 although the simpler 2-anilinomethylene-l-tetralone (145) does not give a phenanthridine derivative under similar conditions.30 177 The observation30 that ring closure of 145 with hot formic acid, followed by treatment with ammonia, gives 5,6,8,9-tetrahydro-dibenz[c7t]acridine has been confirmed, and is rationalized in terms of an intermediate xanthylium formate. The nitrogen atom in the final product comes from the ammonia used in the reaction.177... 

Nucleophilic Reactions of Aromatic Heterocyclic Bases Heterocyclic aromatic compounds containing a formal imine group (pyridine, quinoline, isoquinoline, and acridine) also react readily with nucleophilic reagents. A dihydro-derivative results, which is readily dehydrogenated to a new heteroaromatic system. Since the nucleophile always attacks the a-carbon atom, the reaction formally constitutes an addition to the C=N double bond. An actual localization of the C=N double bond in aromatic heterocyclic compounds is incompatible with molecular orbital theory. The attack of the nucleophilic reagent occurs at a site of low 77-electron density, which is not... 

The decreasing reactivity of the most familiar aromatic heterocyclic compounds with nucleophilic reagents may be illustrated by the following sequence quinoxaline > acridine > phenanthridine > isoquinoline > quinoline > pyridine. Acridine is alkylated in the 4-position, phenanthridine and quinoxaline in the a-position, isoquinoline in the 1-position, and quinoline and pyridine in the 2- or 4-positions. Weaker nucleophilic reagents seem to enter the 4-position of the pyridine and quinoline rings. If the addition occurs readily and in good yield, the intermediate dihydro derivative may sometimes be isolated otherwise, the product of the subsequent oxidation results. In synthetic work the dihydro derivative is usually directly oxidized. 

Aktivierte Hetarene reagieren mit Phosphorigsaure-trialkylestern in Acetonitril bei 25° in Gegenwart von Natriumjodid. So erhalt man z.B. in hohen Ausbeuten 5,10-Dihydro-acridin-10-, bzw. 1 OH- (Dibenzo[b e ]pyran)-10- sowie 10H-(Dibenzo[b e thiopyran)-10-phosphonsdure-diethylester444 ... 

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