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Reduktion der Cyclohexenone (I) mit Zn, das durch AgOAc aktiviert wurde, ergibt als Hauptprodukte die Cyclohexadienole (II), deren Reaktionsverhalten gegenüber den β‐Diketonen (III) mit aktiver Methylengruppe unter den Bedingungen der Michael‐Reaktion untersucht wird.

Synthesis of New Benzo[c]phenanthridineDerivatives. -Three component condensation of naphthylamine (I) with triethyl orthoformate and dimedone or reaction of amine (I) with 2-acetylcyclohexanedione deivatives (VI) affords corresponding enamino diketones (IV) and (VIII), resp., which undergo PPA-mediated intramolecular cyclizations to furnish new benzophenanthridine derivatives in good yields. Attempted intramolecular cyclization of enamino diketone (X) derived from cyclopentanedione (IX) fails. -(PYRKO, A. N.; Russ.

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The major products of the three-component condensation of a fl-dicarbonyl compound flenaminocarbonyl compound, and ethyl 3, 3, 6, 6-tetramethyl-l,2, 3, 4, 5, 6, 7, 8-octahydro-l,8-acridinedione [5, 6]. Octahydroacridines Ib and Ic were obtained [7] by the condensation of enamino ketones I/Ib and mc from dimedone and 1,3-cyclohexanedione (lie) with ethyl orthoformate in acetic acid. The maximum yields were 44% for Ia, 53% for Ib, and 21% for Ic (Table I). Analysis of these methods for the preparation of symmetrical pyridine derivatives Ia-c led us to study the reaction of a three-component system consisting of a ~-dicarbonyl compound II, ~-enaminocarbonyl compound III, and ethyl orthoformate with the aim of increasing the yield of products Ia-c as well as to obtain new products I, including asymmetric derivatives.The reaction of ethyl orthoformate with [3-dicarbonyl compounds IIa-c presumably leads to the formation of unsaturated diketoesters which, as shown [5] in the case of ethyl ethoxymethylenacetoacetate (IVa), react with enamines IIIa-c (obtained from Ha-c, respectively) to give products I.The reaction was carried out in the presence of acetic acid in accordance with the procedure described [8] for the synthesis of ~-enamino diketones from ~-diketones, primary amines, and ethyl orthoformate. Indeed, pyridine derivatives Ia-e were obtained as the major products. Minor products, namely, tricarbonyl compounds Va,b,d as well as tetrahydropyridine derivative VI (obtained when IIa and Ilia were the starting reagents) (Scheme I) were also isolated from the reaction mixture in the reaction with ethyl orthoformate, ethyl acetoacetate, dimedone, and the resultant enamines (Ha and Ilia, lib and Ilib, and lib and NIa).The structures of these products were established by the spectral and elemental analysis data (Tables 1 and 2). Thus, the PMR spectra of lia-e have a characteristic singlet for 4-H at 8.68-8.82 ppm and signals, whose position, shape, and intensity correspond to the substituent protons. The PMR spectra of imines Va,b,d have characteristic

Reductive cleavage of the anellated isoxazolines (I) with Raney‐nickel in the presence of acids gives the dihydroxy ketones (II) and/or its dehydration products (III).

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