Photochemical reaction of 9-nitro-substituted anthracene-like molecules 9-methyl-10-nitroanthracene and 12-methyl-7-nitrobenz[a]anthracene

Photolysis of 9-methyl-10-nitroanthracene in chloroform or methanol produces mainly two products 9-methyl-9-nitrosoanthracen-10-one and 9,10-anthraquinone in about 4:1 ratio under ambient air. The formation of 9-methyl-9-nitrosoanthracen-10-one confirms the proposed excited state rearrangement reaction of the nitro group peri to two hydrogens and perpendicular to the aromatic rings. The nitro group rearranges to a nitrite, followed by breaking of the N–O bond producing NO radical. The NO radical further forms a bond with the carbon on the opposite site of the benzene ring through radical recombination. Photolysis of 12-methyl-7-nitrobenz[a]anthracene produced several nitroso ketone-like compounds which further convert to an aldehyde. Photolysis of the desmethyl nitro compounds, 9-nitroanthracene and 7-nitrobenz[a]anthracene, produced the respective quinones.     

9,9′-Thiobis-(1,2,3,4,7,8-hexahydro-7-methyl-6H-pyrimido[1,6-a]pyrimidine-6,8-dione)

The 6-(3-hydroxypropylamino)-3-methylpyrimidine-2,4-dione (1) did not afford the expected 6-(3-chloro-propylamino)- derivative on reaction with thionyl chloride, but, instead, the pyrimidine rings were joined via a sulfur bridge to give 9,9′-thiobis(1,2,3,4,7,8-hexahydro-7-melnyl-6H-pyrimido[1,6-a]pyrirnidine-6,8-dione) ( 3 ). An identical 9,9′-thiobis- derivative 3 was obtained when reacting thionyl chloride with 1,2,3,4,7,8-hexahydro-7-methyl-6H-pyrimido[1,6-a]pyrimidine-6,8-dione ( 4 ). We suppose the sulfoxide- derivative 2 to be the intermediate of both routes: it underwent reduction to the final sulfide 3 in excess thionyl chloride.     

Synthesis of 3a,4,6,7,11b,12-hexahydro-3a-methyl-7-phenylbenzo[a]furo[2,3-g]quinolizines

By alkylation of stereoisomeric 7a-methyl-2-oxo-5-phenylfuro-[2,3-c]piperidines with phenacyl bromide and subsequent reduction of the keto group by sodium borohydride, amino alcohols were obtained; heating of these products in 70% sulfuric acid affords 3a,4,6,7,11b,12-hexahydro-3a-methyl-7-phenylbenzo[a]furo[2,3-g]quinolizines. It was found that the cis-quinolizidine, upon heating to 150°C in acetic acid, is isomerized to the trans-quinolizidine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1679–1682, December, 1993.     

Synthesis of 3-methyl-2,3,4,4a,5,6-hexahydro-1H-benzofuro[3,2-e]isoquinoline-7(7aH)-ones

The 2,3,4,4a,5,6-hexahydro-1H-benzofuro[3,2-e]isoquinoline-7(7aH)-one ring system is prepared from a 4-arylpyridine precursor by sequentil intramolecular enolate addition to a pyridinium ion, Dieckmann cyclization, and catalytic hydrogenation.     

Synthesis and Crystal Structure of 7-Ethoxycarbonyl-2-methyl-6-methylthio-lH-imidazo[1,2-b]pyrazole

The title compound 7-ethoxycarbonyl-2-methyl-6-methylthio-1H-imidazo[1,2-b]-pyrazole (Mr = 239.29) was synthesized and structurally characterized by IR, 1H NMR and single-crystal X-ray diffraction. It belongs to the triclinic system, space group P1, with a = 8.0461(10), b = 8.5534(11), c = 9.5605(12) A, α = 64.804(2), β = 74.231(2), γ = 76.885(2)°, V= 568.27(12) A3, Z = 2, Dc = 1.398 g/cm3,μ= 0.274 mm-1, F(000) = 252, the final R.= 0.0454 and wR = 0.1261. A total of 3360 reflections were collected, of which 2466 were independent (Rint = 0.0138) and 2154 were observed with I > 2σ(Ⅰ).     

Stereoselective syn epoxidation of the dihydrodiols of dibenz[a,h] anthracene and 7-methylbenz[a] anthracene

Epoxidation of the bay region dihydrodiols of the title hydrocarbons affords stereoselectively the corresponding syn diol epoxides rather than the anticipated isomeric anti diol epoxides, indicative of a dominant cis-directing effect of the benzylic vs the allylic axial hydroxyl groups.     

Synthesis and Crystal Structure of 7-Ethoxycarbonyl-2-methyl-6-methylthio-1H-imidazo[1,2-b]pyrazole

The title compound 7-ethoxycarbonyl-2-methyl-6-methylthio-lH-imidazo[1,2-b]- pyrazole （Mr = 239.29） was synthesized and structurally characterized by IR, ^1H NMR and single-crystal X-ray diffraction. It belongs to the triclinic system, space group P1, with a =8.0461（10）, b = 8.5534（11）, c = 9.5605（12）А,α= 64.804（2）,β= 74.231（2）, γ= 76.885（2）°, V = 568.27（12）А^3, Z = 2,Dc= 1.398 g/cm^3,μ= 0.274 nunl, F（000） - 252, the final R = 0.0454 and wR = 0.1261. A total of 3360 reflections were collected, of which 2466 were independent （R_int = 0.0138） and 2154 were observed with I〉2σ（I）.     

The synthesis of monomethoxy-6-methyl-7H-indeno[2,1-c]quinolines

A series of monomethoxy-6-methyl-7H-indeno[2,1-c]quinolines has been prepared by cyclization of the appropriate 1,3-dioxoindan-2-yl-ethylideneanilines, followed by Wolff-Kishner reduction.