6(5H)-phenanthridinones. III. halo-6(5H)phenanthridinones

Halogenation of 6(5H)-phenanthridinone or its 3,8-dihalo derivatives with N-bromo or N-chlorosuccinimide in dimethylformamide gives the corresponding 2-halophenanthridinones (I,V,XI-XIV). Further halogenation of 2-halo-6(5H)-phenanthridinone with the appropriate N-halosuccinimide, in the same medium, gives the corresponding 2,4-dihalo derivatives (II,VI). NXS/DMF is found to be a very convenient halogenating system in these preparations. 1,3,8-Trihalo-6(5H)-phenanthridinones (XIX,XX) are prepared from the 1-nitro derivatives which are obtained by a Schmidt rearrangement of 2,7-dihalo-4-nitro-9-oxofluorenes. Similarly, rearrangement and further reaction of 2-nitro-5-chloro-9-oxofluorene (XXI) leads to 3,10-dichloro-6(5H)-phenanthridinone (XXIV). UV absorptions as well as selected IR absorptions of these 6(5H)-phenanthridinones are described.     

Reactions of 5-hydroxy-6-oxo steroids-iii : Acid-catalysed reactions of 3β-acetoxy-5-hydroxy-5α-cholestan-6-one

Aromatization of the title compound with selected acidic catalysts has been investigated. It has been established that depending upon the reaction conditions trienone 2,1 -methyltrienone3, dienone 4, diacetoxyketone5 or dione 6 are formed as the major products. Dienone 4 and dione 6 are the main compounds of the reactions of tosyloxyketone 10 with KHSO₄ and HBr_aq, respectively. The reaction of acetoxyketone 8 with HBr_aq furnishes epimeric 3-bromoketones 12 and 13 in the ratio about 1:1.     

5-羟基-3,4-二氢异喹啉-1-酮的合成

以异喹啉为起始原料,经成盐、磺化得异喹啉-5-磺酸(3),3与熔融的氢氧化钠和氢氧化钾反应得1,5-二羟基异喹啉(4),以5%Pd-C为催化剂还原4得5-羟基-3,4-二氢异喹啉-1-酮(1),总收率47.6%。1的结构经1H NMR和MS确证。     

3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮的合成

报道了以草酸二乙酯为原料,制备具有焦糖香味的香料化合物3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮的方法:首先乙基溴化镁与草酸二乙酯通过格氏反应,以约50%产率生成2-氧代丁酸乙酯,然后其在碳酸钾的作用下发生缩合反应,以约94%产率得到3-羟基-4-甲基-5-乙基-5-乙氧羰基-2(5H)-呋喃酮,再通过水解、脱羧反应,得到3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮.路线总收率约36%.     

Synthesis and structure of bromonitro-6(5H)-phenanthridinones

Treatment of 2-bromo-6(5H)-phenanthridone with nitrating mixture or fuming nitric acid results in nitration, debromination, and bromination in the 10-position. The brominating agent is apparently Br⁺, formed in the reaction mixture following replacement of the bromine in the 2-position by a nitro-group. Monocrystals of 2-bromo-1,4,8-trinitro-6(5H)-phenanthridinone and 10-bromo-2,4,8-trinitro-6(5H)-phenanthridinone have been subjected to x-ray diffraction examination. PMR has been used for structural identification.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 789–795, June, 1990.We thank A. N. Sobolev for assistance in calculating the structure of (III).     

Synthesis and structure of nitro-substituted 6(5H)-phenanthridinones

Methods for the preparation of nitro-substituted 6(5h)-phenanthridinones were examined. The nitration of 6(5H)-phenanthridinone, 5-methyl-6-(5H)- phenanthridinone, and 2-bromo-6(5H)-phenanthridinone was studied, and 2-, 3-, 4-nitro-, 2,4-, 2,8-, 4,8-dinitro-, 2,4,8-trinitro-, and 2,4,8,10-tetranitro-6(5H)-phenanthridinones, 2,4,8-trinitro- and 2,4,8,10-tetranitro-6-(5H)-phenanthridinones, and 2-bromo-4,8-dinitro- and 2-bromo-4,8,10-trinitro-6-(5H)-phenanthridinones were obtained. Proton magnetic resonance spectroscopy was used to identify the structure and predict the orientation of substitution in the nitration of 6(5H)-phenanthridinone and its nitro-substituted derivatives. The distribution of the electron density in these compounds was evaluated from an analysis of the chemical shifts of the protons.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1106–1113, August, 1985.     

Synthesis of diarylheptanoids, (5S)-5-acetoxy-1,7-bis(4-hydroxy-3-methoxyphenyl)-3-heptanone and (3S,5S)-3,5-diacetoxy-1,7-bis(4-hydroxy-3-methoxyphenyl)heptane

The total syntheses of the first examples of diarylheptanoid natural products (5S)-5-acetoxy-1,7-bis(4-hydroxy-3-methoxyphenyl)-3-heptanone 1, and (3S,5S)-3,5-diacetoxy-1,7-bis(4-hydroxy-3-methoxyphenyl)heptane 2 isolated from the rhizomes of Zingiber officinale were accomplished using Sharpless epoxidation and cross-metathesis reactions as the key steps.     

Synthesis and stereochemistry of rac.-trans-tetrahydro-6-hydroxy-7-(4-methoxyphenyl)-1,4-thiazepin-5(2H)-one

The base catalyzed reaction of 2-aminoethanethiol ( 3 ) with trans-3-(p-methoxyphenyl)glycidate ( 4 ) gave a mixture of isomeric lactams 5 and 6 , and in addition, a by-product 7 . The structures of these isomers were proven by X-ray crystallography. The data revealed that both isomers adopt the chair conformation in the solid state and the size of the heterocyclic ring in compound 5 is a six- and in compound 6 is a seven-membered ring.     

Synthesis of isoxazolo[4,5-d]pyridazin-4(5H)-ones and 4-acyl-5-hydroxy-3(2H)-pyridazinones

The title compounds were prepared from ethyl 5-acyl- or 5-(1-hydroxyethenyl)isoxazole-4-carboxylates which in turn were prepared from ethyl 3-methylamino-2-butenoate or 3(2H)-furanones.     

Modification of Synthesis of 3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone(MX)

Addition of chlorine to methyl 3-(dichloromethyl)-4,4-dichlorocrotonate (1), a critical procedure in the total synthesis of the title compound MX, was modified by using novel catalysts. A minor modification in the purification of MX was also described.     

Synthesis of (20R)-3β-acetoxy-δ5-bisnorcholenal

Conclusions We have prepared oxirane (IV) by reaction of pregnenolone acetate (II) with fimdyldofium in yields of up to 90%; treatment with BF₃ etherate quantitatively isomerized it to (20R)-3-acetoxy-⁵-bisnorcholenal (III).Translated from Izvestiya Akademii, Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2581–2584, November, 1976.     

A Convenient Synthesis 7,8-Dihydroisoquinolin-5(6H)-One

A new high-yield two step synthesis of 7,8-dihydroisoquinolin-5(6H)-one (3) from 5,6,7,8-tetrahydroisoquinoline (1) is described.     

Synthesis and properties of 6-acetoxy-1,4-dithiocin

The title compound 5 has been prepared from the previously obtained ketone 2 by acetylation of its enolate anion. Spectral properties, reactivity and the results of a crystal structure determination show that 5 is a nonplanar molecule without aromatic character.     

Synthesis and Crystal Structure of 5-Cyclopropyl- 10-（4-fluorophenyl）-7,7-dimethyl-7,8-dihydro-5H- indeno[1,2-b]quinoline-9,11（6H,10H）-dione

The title compound 5-cyclopropyl-10-(4-fluorophenyl)-7,7-dimethyl-7,8-dihydro- 5H-indeno[1,2-b]quinolne-9,11(6H,10H)-dione was obtained by the reaction of 4-fluorobenzal- dehyde, 2H-indene-1,3-dione and 3-(cyclopropylamino)-5,5-dimethylcyclohex-2-enone in the presence of acetic acid under microwave irradiation. Its structure was confirmed by IR and 1H- NMR spectra. The crystal is of monoclinic, space group P21/c with a = 14.138(3), b = 8.952(2), c = 17.140(3) , β = 102.253(3)o, C27H24FNO2, Mr = 413.47, Z = 4, V = 2119.9(8) 3, Dc = 1.296 g/cm3, μ(MoKα) = 0.087 mm-1, F(000) = 872, the final R = 0.0425 and wR = 0.0905 for 2336 observed reflections (I > 2σ(I)). X-ray analysis revealed that the pyridine ring adopts a boat conformation and the six-membered ring fused with it assumes a twist boat conformation.