Tetrahydro tetralone

Autoxidation may in some cases be of preparative use thus reference has already been made to the large-scale production of phenol+ acetone by the acid-catalysed rearrangement of the hydroperoxide from 2-phenylpropane (cumene, p. 128). Another example involves the hydroperoxide (94) obtained by the air oxidation at 70° of tetrahydro-naphthalene (tetralin) the action of base then yields the ketone (a-tetralone, 95), and reductive fission of the 0—0 linkage the alcohol (a-tetralol, 96) ... 

The most widely used route to l-benzazepin-2-ones involves the Beckmann or Schmidt reaction of the easily accessible 1-tetralones. Many biologically active compounds described in this review have been prepared on the basis of these reactions they have been fully reviewed [2], In the Beckmann reaction of 1-tetralone oximes, polyphosphoric acid is used as a catalyst-solvent in most instances. Aryl migration generally takes precedence over alkyl migration under these reaction conditions, and various 1-tetralone oximes substituted on the aromatic and/or aliphatic rings can be converted to the appropriate 2,3,4,5-tetrahydro-l//-l-benzazepin-2-ones (51) [5, 20-23, 36, 59, 65, 80, 107-112]. Both courses of the rearrangement occur in some instances, yielding l-benzazepin-2-ones (51) and the isomeric 2-benzazepine-l-ones, probably due to electronic effects of the substituents [90, 113, 114]. 

Tetrahydro-l-benzazepin-2-ones are formed from a-tetralone by Beckmann or related reactions (CHEC 5.16.4.1.1). Classical ring closures (of the Friedel-Crafts, Dieckmann, etc. types) can also be applied to benzazepine synthesis (74AHC(17)45). 

Tetralins — see also Naphthalenes, tetrahydro-thermochemistry, 2, 368 Tetralones Schmidt reaction azepine synthesis by, 7, 531 Tetramisole—see Imidazo[2,I-6]thiazoie, ( )-2,3,5,6-tetrahydro-6-phenyl-... 

Tetralin Hydroperoxide. See in Vol 8, P207-L under 1,2,3,4-Tetrahydro-l-Naphthyl Hydroperoxide and the following Addril Refs J.S. McDonald J.S. Owens, Investigation of Tetralin Explosion , NAA-SR-4803, Atomics Intrnl, Canoga Park, Contract AT (1 l-l)-GEN-8 (1960) [An expln in a Na-tetralin heat exchanger is reported as being caused by the unforeseen formation of a-tetralin hydroperoxide. The decompn ° hydroperoxide to Oi-tetralone... 

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... 

On the other hand, the Fischer cyclization of cyclohexanone 3-pyridylhydrazone (183) gave a mixture (94% yield) of 6,7,8,9-tetra-hydro-S-carboline (184) and 5,6,7,8-tetrahydro-jS-carboline (185).416 The ratio of 184 to 185 was 63 37, cyclization at the a-position taking place with greater ease than at the y-position. The 3-quinolyl-hydrazone of a-tetralone gave only one product on heating with zinc... 

Substrate 16 reacts under irradiation in DMSO with the enolate anions of 1-indanone (n= 1), 1-tetralone (n = 2), and 6,7,8,9-tetrahydro-benzocyclohepten-5-one (n = 3) to afford fused indoles (Sch. 21) [92]. 

Recent work on the thermal indolization of arylhydrazones has introduced new synthetic possibilities for azaindoles. Kelly et al. refluxed cyclohexanone and deoxybenzoin 2-pyridylhydrazones in diethylene glycol to give 5,6,7,8-tetrahydro-a-carboline (42, R = H) and 2,3-diphenyl-7-azaindole in 70 and 56% yields, respectively, compared with 53 and 12% reported earlier. Similarly, y-carboline 29 was obtained in 95 % yield from cyclohexanone 4-pyTidylhydrazone (lit. 48% ). Several 7-azaindole derivatives were prepared in the same manner. The yields ranged from 5 % for azaindolenine (31) to 88% for 3-phenyl-7-azaindole. 3,3-Dimethyl-7-azaindolenine was obtained in 47 % yield from the isobutyralaldehyde hydrazone. The novel cyclic compounds 40 and 41 were obtained from the 2-pyridylhydrazones of cyclopentanone, a-indanone, and a-tetralone in 67, 95, and 77% yields, respectively. Unfortunately, all attempts to cyclize the acetone, pyruvic acid, and ethyl pyruvate hydrazones were unsuccessful. Also, cyclohexanone and methyl ethyl ketone 5-nitro-2-... 

The reaction may also be performed over a mixed-oxide catalyst at 280° and 100 atm. of ethylene, which serves as the hydrogen acceptor, as illustrated by the preparation of /3-tetralone from 1,2,3,4-tetrahydro-2-naphthol. By the same procedure, diisobutyryl, a diketone, has been prepared from the acyloin (27%). ... 

An attempt has been made to synthesize the morphinane ring-system in this way, and l-(/3-diethylaminoethyl)-2-keto-1 2 3 4-tetrahydro-naphthalene was converted to [oxxvm] by condensation with the appropriate Mannich base methiodide, the product brominated with N-bromosuccinimide, and finally converted to the quaternary salt [cxxix]. Work on the corresponding N-dimethyl series was abandoned when it was found impossible to obtain the requisite substituted /3-tetralone in a state even approaching purity. The synthesis of [cxxx] has been accomplished by the same method, its production being accompanied by the production of [cxxxi] as a result of further ring-extension [43]. 

Tetralone-8-carboxylic acid, an example of a cis unsaturated 1,4-dicarbonyl compound, cyclizes with phenylhydrazine to give 2,7,8,9-tetrahydro-2-phenyl-3//-benzo[<7e]cinnolin-3-one in over 90% yield <81S59>. 

More complex structures can be derived from 1-tetralone through its conversion to (tetrahydro-l-oxo-2-naphthyl)ethanoic acid and subsequent reaction with a heteroaryllithium. Sequential cyclisation to the dibenzofuran or thiophene and propargylation affords fast fading 3,4-dihydronaphtho[2,l-/ [l]benzofuro[2,3-/r]naphtho[l,2-6]pyrans and thiophene analogues <00WOP77007>. 

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