1- Tetralone oxime

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]. 

Tetralone oxime, reduction with lithium aluminum hydride, 48, 23... 

Dilithiated 1-tetralone oxime, prepared by treatment of 372 with an excess of LDA, was condensed with a variety of esters, affording, by acid cyclization, substituted 4,5-dihydronaphth[l,2-r ]isoxazoles 373 (Scheme 90) <2000SC3391>. 

When treated with lithiun diisopropylamide, 1-tetralone oxime is dimetallated. Upon reaction with 2-aminobenzophenones, the dilithiooxime gives a 7-aryl-5,6-dihydrobenz[c]acridine (D.J. Park, T. D. Fulmer and C. F. Beam, J. heterocyclic Chem., 1981, 649). 

Preparation of 1,2,3,4-tetrahydro-l-naphthylideneamino p-slyrenesulfonate (NISS) To a solution of 1-tetralone oxime (13.7g, 0.085 mol) in pyridine (32 ml.) below 10 °C was slowly added p-styrenesulfonyl chloride (19g, 0.094 mol), whidi was freshly prepared from potassium p-styrenesulfonate and PClj according to the method reported ly Iwakura et al (15). The reaction was continued with... 

Hitherto unknown 4,5-dihydrobenz[g]indole is obtained from 1-tetralone oxime and acetylene in the system KOH/DMSO in one stage (Scheme 1.30) [199]. 4,5-Dihydrobenz[g]indoles and their N-vinyl derivatives substituted at the benzene ring are isolated from the reaction of the corresponding 1-tetralone oximes and acetylene in the systems MOH/DMSO (Scheme 1.30) [200]. 

SCHEME 1.30 Synthesis of 4,5-dihydrobenz[ ]indoles from 1-tetralone oximes and... 

Beam et al. (2000) observed that dilithiated 1-tetralone oxime was prepared in excess lithium diisopropylamide and condensed with a variety of esters followed by acid cyclization of C-acylated intermediates to substituted 4,5-dihydronaphth-[l,2-c]-isoxazoles. 

Treatment of the tetralone oxime 2166 with iron powder in DMF in the presence of Me3SiCl 14 and a mixture of acetic anhydride and formic acid gives the N-for-myl amine 2167 in high yield [79]. co-Unsaturated alkoxyalkylazides such as 2168... 

Accordingly, C-8 of a-tetralone oxime displays a larger 3JCN compared with C-4 a, which is more removed from the electron pair, and the ( )- and (Z)-isomers of cyclohexenone oxime can be characterized by their different 3JCN couplings [135]. 

Ketone oximes of the hydronaphthalene series can successfully be transformed into pyrroles. Thus, 4,5-dihydrobenzo[g]indole (38) was prepared in one stage (yield 70%) from a-tetralone oxime (37) and acetylene (Scheme 21) (78ZOR1119). 

On the other hand, Evans and Lockhart126 reported that treating 105 (R -R6 = H R7 = OMe R8 = R9 = H) with PPA gave 18 (R1 = H R2 = OMe) as the major product and only some l-benzazepin-2-one. The use of sulfuric acid resulted in tarry products. The 2-tetralone oxime (118, R1 = R2 = R3 = Me R4 = R5 = H) was reported126 to give 24% yield of 86 (R -R4 = Me Rs = R6 = H). Since then, Conley and Lange127 have studied 2-tetralone oximes and shown another mechanism by which the products of Beckmann rearrangement were formed. When the oxime 118 (R1 = Me R2-R6 = H) was treated with phosphorus penta-chloride, a 93-96% yield of the nitrile 119 was obtained. The nitrile could... 

Aromatization of a-tetralone oximes (1). When the oximes (1) are heated in acetic anhydride and anhydrous phosphoric acid (1,860) for 30 min. at 80, 1V-(1-naphthyl)acetamides (2) are obtained in 82-93% yields. Lower yields have... 

Scheme S.4 Anti- versus syn-migration of tetralone oximes.

SCHEME 1.131 Synthesis of 4,5-dihydrobenzo[,g]indole and its N-vinyl derivative from a-tetralone oxime and vinyl chloride in the KOH/DMSO system. 

Using this methodology, 4,5-dihydrobenz[g]indole and its N-vinyl derivative (50% total yield) have been synthesized from a-tetralone oxime (KOH/DMSO, 140°C-150°C, 3-4 h) (Scheme 1.131) [301],... 

Mikhaleva, A.I., LA. Aliev, R.N. Nesterenko, and G.A. Kalabin. 1982. One-pot synthesis of 4,5-dihydrobenz[ ]indole and its 1-vinyl derivative from a-tetralone oxime and vinyl chloride. Zh Org Khim 18 (10) 2229-2230. 

A three-necked round-bottom flask is fitted with a dropping funnel, a thermometer, and a magnetic stirrer and is heated in a water bath to 30°. Tetralin (1.32 g, 0.01 mole) and 50 ml of 3.5 Anitric acid solution are placed in the flask and brought to temperature. Ceric ammonium nitrate (21.9 g, 0.04 mole) is dissolved in 100 ml of 3.5 N nitric acid, and the solution is added dropwise to the reaction mixture at a rate such that the temperature does not rise and only a pale yellow color is evident in the reaction mixture. At the completion of the reaction (1 to 2 hours), the mixture should be colorless. The solution is cooled to room temperature, diluted with an equal volume of water, and extracted twice with ether. The ether solution is dried with anhydrous sodium sulfate, filtered, and the ether is evaporated. The residue may be distilled to yield a-tetralone (bp 113-11676 mm or 170749 mm) or may be converted directly to the oxime, which is recrystallized from methanol, mp 88-89°. 

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