Mannich Condensation of exo-2,exo-6-Tricyclo[5.2.1.02,6]decan-8-one

Mannich condensation of exo-2,exo-6-tricyclo[5.2.1.02,6]decan-8-one with paraformaldehyde and dimethylamine hydrochloride results in the addition of dimethylaminomethyl fragment at the C⁹ atom to give the exo-9-isomer. The reaction of exo-9-dimethylaminomethyl-exo-2,exo-6-tricyclo[5.2.1.02,6]decan-8-one with hydroxylamine hydrochloride in alcoholic alkali yields the corresponding Z-oxime which undergoes selective rearrangement into exo-10-dimethylaminomethyl-9-aza-exo-2,exo-6-tricyclo[5.3.1.02,6]undecan-8-one by the action of sulfuric acid in acetonitrile.     

Transformations of 2-(3-Hydroxy-3-methyl-1-butynyl)adamantan-2-ol >Catalyzed by Acids

Reaction of 2-(3-hydroxy-3-methyl-1-butynyl)adamantan-2-ol with acetonitrile under Ritter reaction conditions is accompanied by isomerization and partial hydration where the water addition to the triple bond occurs nonselectively. As a result of reaction carried out in the presence of 8 equiv of sulfuric acid a mixture was obtained of N ²-[4-(1-acetylamino-2-adamantyl)-2-methyl-3-butyn-2-yl]acetamide, N ³-[1-(1-acetylamino-2-adamantyl)-3-methyl-2-oxo-3-butyl]-acetamide, and N ³-[1-(1-acetylamino-2-adamantyl)-3-methyl-1-oxo-3-butyl]acetamide in ~10:3:2 ratio. In the presence of 2 equiv of the acid the mixture obtained consisted of N ²-[4-(1-acetylamino-2-adamantyl)-2-methyl-3-butyn-2-yl]acetamide, N ³-[1-(1-acetylamino-2-adamantyl)-3-methyl-2-oxo-3-butyl]acetamide, and 1-(1-acetylamino-2-adamantyl)-3-methyl-2-buten-1-one in the same ratio. In Rupe reaction conditions we obtained instead of the expected ,-unsaturated ketones a mixture of 1-(1-hydroxy-2-adamantyl)-3-hydroxy-3-methylbutan-1-one and 1-(1-hydroxy-2-adamantyl)-3-hydroxy-3-methylbutan-2-one in a 5:3 ratio.     

Transformations of 2α-hydroxy-2,6,6-trimethylbicyclo[3.1.1]-heptan-3-one under conditions of acid catalysis

The transformations of 2a-hydroxy-2,6,6-trimethylbicyclo[3.1.1]heptan-3-one under the conditions of acid catalysis have been studied. It has been shown that this compound can be used for the synthesis of products of various structures: a bridged bicyclic lactone (1,8,8-trimethyl-2-oxabicyclo[3.2.1]octan-3-one), an aromatic compound (carvacrol), and nitrogen-containing derivatives of p-menthane such as 8-acylamino-p-menth-6-en-2-ones. The structures of the compounds synthesized were shown by the results of¹H and¹³C NMR spectroscopies.Institute of Physical Organic Chemistry, Academy of Sciences of the Belorussian SSR, Minsk. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 35–42, January–February, 1990.     

Synthesis and Reactions of 4-cis- and 4-trans-Hydroxy-2e-methyl-4-ethynyl-trans-decahydroquinolines

By treating 2e-methyl-4-oxo-trans-decahydroquinoline with lithium acetylide a mixture of stereoisomeric 4-cis-hydroxy-2e-methyl- and 4-trans-hydroxy-2e-methyl-4-ethynyl-trans-decahydroquinolines was obtained in 3:2 ratio. Their reaction with acetonitrile in the presence of sulfuric acid (Ritter's reaction) results in a mixture of stereoisomeric 4-cis-acetylamino-2e-methyl- and 4-trans-acetylamino-2e-methyl-4-ethynyl-trans-decahydroquinolines in the same ratio. The ethynyl group of alcohols synthesized is not hydrated under conditions of Kuchrerov's reaction. The boiling of the alcohols with formic acid furnished a mixture of 4-acetyl-2e-methyl and 2e-methyl-4-ethynyl-1,2,3,6,7,8,9,10-octahydroquinolines in 1:7 ratio. The former of these compounds under conditions of Ritter's reaction yielded a mixture (1:1.4) of stereoisomeric 4-acetyl-4-trans-acetylamino- and 4-acetyl-4-cis-acetylamino-2e-methyl-trans-decahydroquinolines. From 2e-methyl-4-ethynyl-1,2,3,6,7,8,9,10-octahydroquinoline under the same conditions were obtained both already mentioned stereoisomeric 4-acetylamino-2e-methyl-4-ethynyl-decahydroquinolines (53% of cis-isomer and 35% of trans-isomer in the mixture) and 4-acetyl-4-acetylamino-2e-methyldecahydroquinolines (7% of cis-isomer and 5% of trans-isomer).     

Sterical Hindrances as a Driving Force of Skeleton Rearrangements of Fenchone and Its Oxime in Ritter Reaction

Fenchone (1,3,3-trimethylbicyclo[2.2.1]heptan-2-one) in reaction with acetonitrile in the presence of sulfuric acid (Ritter reaction) due to steric hindrances preventing geminal addition of two nucleophile molecules gives rise to a mixture of 1,2-exo-diacetamido-6-endo,7,7-trimethylbicyclo[2.2.1]heptane, 2-endo6-exo-diacetamido-3,3,6-trimethylbicyclo[2.2.1]heptane, and 2-exo,6-exo-diacetamido-1,3,3-tri- methylbicyclo[2.2.1]heptane in the ratio of 6:4:1. Fenchone oxime under condition of this reaction affords a mixture of stereoisomeric cis- and trans-acetamido-1-methyl-3-(-cyanoisopropyl)cyclopentanes in 2:3 ratio.     

The Efficiency of the Formation of Singlet Oxygen by a Sensitizer Based on Zinc Phthalocyanine

Using zinc octa(diethoxyphosphenylmethyl)phthalocyanine as an example, we determined experimentally the quantum yield of generation of singlet oxygen () which makes it possible to evaluate quantitatively the efficiency of photogeneration of ¹O₂ and the influence of biomolecules on this parameter. It is shown that the efficiency of generation of singlet oxygen by the sensitizers used in photodynamic therapy depends on their state in a solution and increases with disaggregation of the dye and its interaction with biomolecules. It is established that phthalocyanine in an aqueous buffer solution sensitizes the formation of ¹O₂ with the quantum yield = 0.16 ± 0.02. On introduction of the detergent Triton X100 into the buffer solution of phthalocyanine, increases up to 0.48 ± 0.07. In a microheterogeneous medium (buffer + albumin) = 0.42.     

Synthesis and Ritter Reaction of 2-Ethynyladamantan-2-ol

The reaction of adamantan-2-one with lithium acetylide gave 2-ethynyladamantan-2-ol. The latter reacted with acetonitrile in the presence of sulfuric acid through formation of an intermediate classical carbocation, leading to 2-acetylamino-2-ethynyladamantane and 1-acetylamino-2-acetyladamantane at a ratio of 20:1.     

Beckmann rearrangement of the E isomer of cis-4,6,6-trimethylbicyclo[3.1.1]-heptan-2-one oxime

The individual E isomer of 4,6,6-trimethylbicyclo[3.1.1]heptan-2-one oxime has been obtained, and its transformations under the conditions of acid catalysis have been studied. The action of sulfuric acid on a solution of the oxime in acetonitrile leads to the selective formation of 5,7,7-trimethyl-2-azabicyclo[4.1.1]octan-3-one, while the action of hydrochloric acid with heating gives 4-isopropyl-3-methylaniline.Institute of Physical Organic Chemistry, Academy of Sciences of the Belorussian SSR, Minsk. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 29–32, January–February, 1991.