1 l- -dibenzo

Bis(2-nitrophenyl)amine (la) is reduced by zinc/ sodium hydroxide to a mixture of 117/-dibenzo[r, /][l,2,5 triazcpine (2a) and the V-oxidc 3a.325 The reaction of Ar-methylbis(2-ni-trophenyl)amine with lithium aluminum hydride provides 11-methyl-1 l//-dibenzo[c,/][l,2,5]tri-azepine (2b).153... 

It has been reported that 1 l//-dibenzo[h,< ][ ,4]dioxepin-l 1-one (dep-sidone) (243) undergoes photochemical decarboxylation and yields dibenzo-furan (59%) on irradiation with a high-pressure mercury lamp. The authors do not report whether the irradiation was conducted through silica or borosilicate glass. 

The photolysis of 1 l//-dibenzo[c/][l,2]diazepine in acidified EtOH has given the corresponding dibenzodiazepin-ll-one and minor amounts of 2,2 -diaminobenzophenone and 2,2 -diamino-diphenylmethane <67AJC2229>. Similar treatment of the 3,8 -dichloro- and 3,8 -dibromo-ll/7-dibenzodiazepines, in the same solvent, also affords their 11-ethoxy derivatives (68), which adds support to the proposed photoinduced intermolecular hydride-transfer mechanism <91JIC299>. 

According to the Hantzsch-Widman system, the seven-membered unsaturated hcterocyclc with one sulfur atom is named thiepin (1). The three different benzothiepins are assigned by the position of sulfur 1-benzothiepin (2), 2-benzothiepin (3) and 3-benzothiepin (4). Of the four possible dibenzothiepins only dibenzo[6,r/]thiepin (5) and dibenzo[A,/]thiepin (6) are of importance for synthesis, while the other two isomers, which contain unfavorable o-quinoid structures, exist mainly as the stable dihydro compounds, i.c. 5,7-dihydrodibenzo[c,t ]thiepin (7) and 6,1 l-dihydrodibenzo[6,c ]thiepin (8). Benzannulation over all double bonds results in tri-benzo[6,(7,/]thiepin (9). 

CN 10,1 l-dihydro-57/-dibenzo[a,dimethylamino)ethyl]oxime monohydrochloride... 

The 1,4-diacetoxylation was also extended to the use of other acyl groups than acetyl. Thus, an unsymmetrical 1,4-acetoxy-trifluoroacetoxylation of 1,3-dienes was developed by the use of added trifluoroacetic acid to the acetic acid used as the solvent330. With the use of acetone as the solvent with an added carboxylic acid a general diacyloxylation was obtained and, for example, the 1,4-dibenzoates of 2-cycloalkene-l,4-diols were prepared directly from the corresponding l,3-cycloalkadienes33d. 

Aminomorphanthridine was reacted with EMME in 1,2,4-trichlorobenzene under nitrogen at 100°C for 1 hr, then at reflux temperature for 3 hr, to give 53% of dibenzo[c/]pyrimido[l,2-n]azepin-4-one (1159) and 1% of dibenzo[c/]pyrimido[ 1,2-n]azepin-2-one (1160) (80JHC341). 

A. 1,1-Dibromo-2,2-bis(chloromethyl)cyclopropane (1). Into a 1-L, threenecked, round-bottomed flask, equipped with an efficient mechanical stirrer, a thermometer, and a condenser equipped with a potassium hydroxide drying tube, are placed 54.1 g (0.403 mol) of 3-chloro-2-(chloromethyl)propene (Note 1), 212 g (0.805 mol) of bromoform (Note 2), 1.70-2.00 g (14.4-16.9 mmol) of pinacol (Note 3), and 1.45 g (3.94 mmol) of dibenzo-18-crown-6 (Note 4). With very vigorous stirring (Note 5), 312 g of an aqueous 50% sodium hydroxide solution that has been cooled to 15°C is added in one portion. The reaction mixture turns orange, then brown, then black within 5 min, and the temperature of the reaction mixture begins to rise. Within 20 min, the internal reaction temperature is 49-50°C at which point the reaction flask is cooled with a room-temperature water bath, and the reaction temperature decreases to ca. 

Alkyl ethynyltellurides from dialkylditellurides and pressurized acetylene in the presence of electrophilic reagents (typical procedure) To a mixture of di-isopropyl ditellurides (4.5 g, 13 mmol), powdered KOH (20 g, 303 mmol), methyl iodide (2 g, 14 mmol), dibenzo-18-crown-6 (0.2 g) and benzene (50 mL) was heated (40-50°C) in a 1 L rotating autoclave under acetylene pressure (14 atm) for 5 h. After addition of water the mixture was extracted with benzene, the organic layer was separated and dried over KjCOj. After evaporation of benzene the residue was diluted with ether and precipitated dibenzo-18-crown-6 was fdtered off. After evaporation of ether the residue was distilled in vacuo giving the product (2.3 g, 96% yield). 

Very recently, a series of novel carbocations and carboxonium ions were generated from 77/-benzo[c]fluorene (80), 1 l//-benzo[Z)]fiuorene (81), ll//-benzo[a]fluorene (82), 2-methoxy- (83), 7-methoxy- (84), and 9-methoxy-l l//-benzo[u]fluorene (85), 7//-dibenzo-[c,g]fluorene (86), 137/-dibenzo[u,g]fluorene (87), 2-methoxy-13//-dibenzo [u,g]fluorene (88), and 5,6-dihydro-13//-dibenzo[u,g]fluorene (89) (Fig. 30). Charge delocalization modes in the resulting carbocations were derived based on experimental and/or computed (GIAO-DFT) A8 C NMR values and via the NPA-deiived changes in charges (A ). 

Ein Beispiel fur intermolekularen RingschluB durch Cl/Amin-Austausch bei gleichzeitiger Lactam-Bildung ist die Synthese von 1 l-Oxo-10,11-dihydro-5H-(dibenzo[b e]-l,4-diaz-epin) (40%) aus 1,2-Diamino-benzol und 2-Chlor-benzoesaure1. 

Two furo-annelated benzo[c]furans, a benzo[2,l-Z) 3,4-c ]difuran (341) and a benzo[1.2-/ 3,4-c ]difuran (344) have been described. Acid-catalyzed ring closure of bisfuran 340, which is available from trans-trans-1,4-dibenzo-ylbutadiene (339) and /ranx-dibenzoylethylene. yields 341 in 83% yield. An independent synthesis which starts from 4-benzoyl-2-phenylfuran (343) is outlined in Scheme 21 the isomeric compound has been obtained similarly (Scheme 22). 

MF5 reacts with aliphatic ethers to yield volatile adducts of the [MF5(OR2)] type DMSO forms the bis adducts [MF5(DMSO)2]. MCI5 and MBr5 form numerous [MX5(ether)] adducts. Abstraction of oxygen from the ethers occurs at around 100 °C to produce oxo trihalides and alkyl halides.1 The ability of crown ethers to coordinate and reduce MC1S has been explored 104 [(MC15)2L] and [MC1SL] were isolated with L = dibenzo-18-crown-16, 18-crown-6 and 15-crown-5. NMR data indicate that these compounds disproportionate. 

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