C -NAPHTHALENONE

Protected cyanohydrins may be employed as acyl anion equivalents in 1,4-additions in the presence of HMPA129. For instance cyanohydrins prepared from arylaldehydes add in a 1,4-fashion under thermodynamic control (THF or THF/HMPA) to cyclohexenone, isophorone and decalone systems in the latter case c/.s-octahydro-2(l/f)-naphthalenones are exclusively obtained 130-131. 

To a stirred solution of 5 mmol of LDA in 4 mL of THF at — 78 °C is added under an argon atmosphere 0.97 g (5 mmol) of a-ethoxyethoxybenzeneacetonitrile. The mixture is stirred for 0.5 h and subsequently 0.75 g (5 mmol) of hexahydro-2(177)-naphthalenone are added followed by stirring at — 78 °C for 1 h. After this period the mixture is allowed to warm to 0°C and stirred at that temperature for an additional hour. 20 mL of sat. aq NH4C1 are added and the resulting mixture is extracted three times with 30 mL of diethyl ether. The combined ether layers are washed with water until neutral and dried over MgSO . The solvent is evaporated and the remaining solid material is recrystallized from ethanol to afford the adduct yield 1.55 g (90%) mp 168-169 C. 

In chain reactions involving three termination steps (two uncrossed and one crossed) the quantity = 1c /(1c 1c )1/2 is frequently used to interrelate the cross-termination constant with the two uncrossed termination constants. For many different types of radical < is found to be about 1 (or alternatively, if the statistical factor of 2 favoring the crossed termination process is ignored in the definition of the rate constants, < 2). In the present reaction system —3-6, in agreement with the value obtained by Russell at 90°C. (26). The crossed termination constant itself is somewhat less than half the value found for kt. This seems reasonable since only one hydrogen atom will be available for transfer in the crossed termination, compared with the two that are available in the self-reaction of two tetralylperoxy radicals. In addition, steric hindrance to reaction should be greater for the crossed termination than for Reaction 8. The products are presumably cumyl alcohol, a-tetralone [3,4-dihydro-l(2H)naphthalenone], and oxygen (28). 

To the above toluenic solution containing levobunolol as free base, 16 ml ethanol and the stoichiometric amount of hydrogen chloride were added. The stirred mixture was cooled below 10°C and kept at this temperature for one hour. The precipitated solid was filtered, washed with toluene, recrystallized twice from 43 ml ethanol and dried to give 10.0 g (51% yield) of (-)-3,4-dihydro-5-(3-(tert-butylamino)-2-hydroxypropoxy)-l(2H)-naphthalenone hydrochloride (levobunolol hydrochloride) having a rotary power at 25°C below -19°. 

A solution of 4-(3,4-dichlorophenyl)-3,4-dihydro-l-(2H)-naphthalenone (50 g, 0.17 mole) in tetrahydrofuran (800 ml.) was cooled to 0° to 5°C and treated with 52 ml (1.20 moles) of methylamine (condensed at 0°C). Titanium tetrachloride (10 ml, 0.087 mole) was added dropwise to the resulting solution (vigorous reaction), with the reaction mixture stirred at below 10°C during the addition period. After the addition was completed, the reaction mixture was stirred for 17 h at room temperature under nitrogen and then filtered. The solids were washed thoroughly with tetrahydrofuran and the combined filtrates were concentrated under vacuum to 600 ml. to remove excess methylamine. Further evaporation of an aliquot to dryness and trituration with hexane yielded the Schiff base (melting point 145°-146°C). 

In 1899, Marckwald discovered that two separate organic compounds, 2, 3, 4, 4-tetrachloro-1 -(4//)-naphthalenone and benzo [c]-l, 8-naphthpyridine hydrochloride, developed color in sunlight and lost this color when placed in the dark. The study of photochromic materials had begun. 

Starting from ( + )-8a-cyano-octahydro-2(l/f)-naphthalenone oxime, the corresponding (2/ ,4a/ ,8a.V)-2-chloro-2-nitmso derivative was prepared and employed in the cycloaddition with (2 , 4 )-2,4-hexadiene. The dihydro-1,2-oxazine 1 was obtained in good yield, but with only 39% ee. The configuration at C-6 was established as S, by correlation with known compounds40. 

Photocyclisation of 8-alkoxy-l,2,3,4-tetrahydro-l-naphthalenones and 4-alkoxy-6,7,8,9-tetrahydro-5H-benzocyclohepten-5-ones gives naphtho[l, 8-bc]furans and cyclohepta[cd]benzofurans respectively, and conformational and substituent effects of 1,5-biradicals in the cyclisation process are discussed." " The same authors also describe substituent effects on the photocyclisation of ethyl 2-(8-oxo-5,6,7,8-tetrahydro-l-naphthyloxy)acetates and ethyl 2-(5-oxo-6,7,8,9-tet-rahydro-5H-benzocyclohepten-4-yloxy)acetates to give naphtho[l,8-bc]furans and cyclohepta[c,d]benzofurans respectively." Also reported are cyclisations involving photogenerated radical cations of unsaturated silyl enol ethers, fragmentation cyclisations of unsaturated ot-cyclopropyl ketones which occur by photoelectron transfer and give polycyclics, and kinetic and theoretical studies of [2+3] cycloadditions of nitrile ylids. These reactions have been studied mechanistically and their synthetic potential investigated. 

Acetyl-6,8-dihydroxy-3-methoxy-4,4-dimethyl-1 (4//)-naphthalenone, A-80020 Deoxycollybolidol, in C-80147 7,7fl-Dihydro-3,6,7-trihydroxy-1 a-(3-methyl-2-butenyl)naphth[2,3-Z ]oxiren-2(la//)-one, D-70277... 

A somewhat different situation arises for 4,4-dialkylcyclohex-2-enones bearing an additional CH-substi-tuent on C(3). Thus, 4a-methyl-4,4a,5,6,7,8-hexahydro-2(3H)-naphthalenone (9) affords selectively the... 

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