9,10-Dimethoxy-3,3-dimethyl-2,3,4,6,7,11b,12,13-octahydro-1H-isoquino[2,1-a]quinolin-13-one
1-O-ethyloxime and
9,10-dimethoxy-3,3-dimethyl-2,3,4,6,7,13-hexahydro-1H-isoquino[2,1-a]quinolin-13-one 1-O-ethyloxime

Akhrem A.A., Gulyakevich O.V., Mikhal'chuk A.L.,
Rubinov D.B., Rubinova I.L.

Institute of Bioorganic Chemistry, Minsk, Belarus
tel.: +(375-17) 264-87-61, fax: +(375-17) 263-71-32, e-mail:

9,10-Dimethoxy-3,3-dimethyl-2,3,4,6,7,11b,12,13-octahydro-1H-iso-
quino[2,1-a]quinolin-13-one (3). A mixture of 0.57 g (3 mmol) 3,4-dihydroisoquinoline 1 and 0.68 g (3 mmol) ethoxyimine 2 [1] in 10 ml methanol is refluxed in an atmosphere of Ar. A course of reaction is monitored by TLC (silica gel 60 F254, eluent chloro-formmethanol 9.5 : 0.5). Upon completion of the reaction, the mixture is evaporated under reduced pressure. A residue is dissolved in as-distilled chloroform and then flesh-chromatographed on 11 g neutral silica gel (Chemapol 5/40) by using as-distilled chloroform as an eluent. Target ethoxyimino derivative 3 is precipitated from collected eluates with hexane. Compound 3 is obtained as white acicular crystals. Yield 82.5%, m.p. 109–112С.The structure of compound 3 was confirmed by IR (Protégé 460, KBr), UV (Specord M-400, EtOH), 1H and 13C NMR (AM-200 Bruker, 200.11 MHz for 1H and 90.54 MHz for 13C, CDCl3) spectra and elemental analysis.

9,10-Dimethoxy-3,3-dimethyl-2,3,4,6,7,13-hexahydro-1H-isoquino[2,1-a]quinolin-13-one 1-O-ethyl-oxime (4). (a) A mixture of 0.57 g (3 mmol) 3,4-dihydroisoquinoline 1 and 0.68 g (3 mmol) ethoxyimine 2 in 7 ml glacial acetic acid is held at 80–100С in an atmosphere of Ar. A course of reaction is monitored by TLC. After the end of the reaction, the mixture is evaporated under reduced pressure. A residue is dried, dissolved in chloroform and flesh-chromatographed on 8 g silica gel (Chemapol 5/40) by using a chloroformmethanol mixture (8 : 2) as an eluent. Collected eluate is evaporated, and a residue is crystallized from an ethanolether mixture. Compound 4 is obtained as white lamellar crystals. Yield 81%, m.p. 87–92С.

(b) 0.8 g (2 mmol) oxime 3 are dissolved in 10 ml ethanol. To this solution, 10 mg
p-toluenesulfonic acid are added, after which the mixture is refluxed, transformation of 3 to 4 being monitored by TLC. Upon completion of the reaction (in about 3 h), the mixture is evaporated, and a residue is dissolved in chloroform. Then the solution is washed with a 5% solution of NaHCO3, water, dried with Na2SO4, filtered, and evaporated. A residue is crystallized from ethanol upon precipitation with ether. Compound 4 is obtained as white lamellar crystals identical to those prepared by procedure (a). Yield 87%, m.p. 88–92С. The structure of compound 4 was confirmed by IR (Protégé 460, KBr), UV (Specord M-400, EtOH), 1H and 13C NMR (AM-200 Bruker, 200.11 MHz for 1H and 90.54 MHz for 13C, CDCl3), mass (Shimadzu MS QP-5000, 70 eV) spectra and elemental analysis.

  1. Lakhvich F.A., Lis L.G., Rubinov D.B., Rubinova I.L., Kurbako V.Z.,
    Bykhovets A.I., VestsiAkad. NavukBSSR,Ser. Khim. Navuk1989(1) 51.

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