Reaction of perfluorinated 1-ethyl-, 1,1-diethyl-, and 1,2-diethylcyclobutabenzenes with pentafluorobenzene in SbF<Subscript>5</Subscript>

Perfluoro(1-ethyl-1,2-dihydrocyclobutabenzene) reacts with pentafluorobenzene in SbF5 to give perfluoro(1-ethyl-2-phenyl-1,2-dihydrocyclobutabenzene). Analogous reaction of a mixture of perfluoro(1,1-diethyl-1,2-dihydrocyclobutabenzene) and perfluoro(1,2-diethyl-1,2-dihydrocyclobutabenzene) leads to the formation (after hydrolysis of the reaction mixture) of perfluorinated 7-phenyl-8,8-diethylbicyclo[4.2.0]octa-1,4,6-trien-3-one, 1,1-diethyl-2-(4-oxocyclohexa-2,5-dienylidene)-1,2-dihydrocyclobutabenzene, and 2-(pent-2-en-3-yl)benzophenone (from the 1,1-isomer) and perfluorinated (E)-1,2-diethyl-1-phenyl-1,2-dihydrocyclobutabenzene, 7,8-diethyl-8-phenylbicyclo[4.2.0]octa-1,4,6-trien-3-one, and 1-[2-(1-phenylprop-1-en-1-yl)-phenyl]propan-1-one (from the 1,2-isomer).     

Synthesis of p-aminobenzamides of several aminopyrazolidines: Potential antiarrhythmic agents related to procainamide

Four heterocyclic amines including 1,2-diethyl-3-aminomethylpyrazolidine ( 3 ), 1-(2-aminoethyl)-2-methyl-pyrazolidine ( 5 ), 1,2-dimethyl-4-aminomethylpyrazolidine ( 7 ), and 1,2-diethyl-4-aminopyrazolidine ( 9 ) have been synthesized. Each was acylated with p-nitrobenzoyl chloride and afforded the corresponding p-nitro-benzamides 10, 12, 14 , and 16. Catalytic reduction of these nitro intermediates gave the corresponding p-aminobenzamides 11,13,15 , and 17 . The latter compounds are analogs of procainamide and two of them, 15 and 17 , were evaluated in the isolated cardiac Purkinje fiber preparation by measuring their effects on the action potential upstroke velocity.     

Naphth[1,2-d]oxazole intermediates in the preparation of 3-hydroxy-4-(1-alkyl-3-methyl-5-hydroxy-4-pyrazolyl)-azo-1-naphthalenesulfonamide dyes

Acylation of 4-amino-3-hydroxy-1-naphthalenesulfonic acid ( 3 ) with benzoyl chloride in pyridine gave pyridinium 3-hydroxy-4-(N-benzoylamino)-1-naphthalenesulfonate ( 12 ) which was converted by thionyl chloride followed by diethylamine into N,N-diethyl-2-phenylnaphth[1,2-d]oxazole-5-sulfonamide ( 14 ). The naphthoxazole moiety was hydrolyzed with potassium hydroxide and the resulting N,N-diethyl-4-amino-3-hydroxy-1-naphthalenesulfonamide ( 11 ) coupled with 1-alkyl-3-methyl-5-pyrazolones. The 2-phenylnaphth[1,2-d]oxazole intermediates and various by-products were investigated.     

Influence of different substitution in pyrazolium ionic liquids on catalytic activity for the fixation of CO2 under solvent- and metal-free conditions

Three pyrazolium ionic liquids, 1,2-diethylpyrazolium bromide (DEPzBr), 1,2-diethyl-3-methylpyrazolium bromide (DEMPzBr), and 1,2-diethyl-3,5-dimethylpyrazolium bromide (DEDMPzBr), are firstly applied as catalysts for coupling reaction of carbon dioxide (CO₂) and propylene oxide (PO) with the propylene carbonate (PC) yields in a range of 82.7%–88.7% under a benign condition, 120?°C, 2.0?MPa initial CO₂ pressure and 4?h with 0.5?mol% catalysts loading. The relationship between structure and catalytic activity of pyrazolium ionic liquids are investigated by two different theoretical models, which indicates that both electrostatic interaction and hydrogen bond promote the ring-opening of PO. Both the theoretical and experimental results present that the catalytic activity decreases in the sequence of DEPzBr?>?DEDMPzBr?>?DEMPzBr. Pyrazolium ionic liquids would be employed as a novel efficient single-component catalyst without solvent and co-catalyst. It is expected that we would open an express pathway to develop new catalysts with the desired properties.     

Ring expansion of 4,4-diethyl-1,2-dithiolane in the reaction with butylacetylene. Involvement of anion and radical intermediates

The action of lithium butyl acetylenide in THF causes 4,4-diethyl-1,2-dithiolane to undergo ring-opening to form 2,2-diethyl-4-thia-5-decyne-1-thiol, which cyclizes to give 2-butyl-6,6-diethyl-5,6-dihydro-1,4-dithiepin by either a homolytic or a nucleophilic mechanism. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 204–206, January, 1997.     

Synthesis of 2,6-diethyl-3-methacroyloxymethyl-1,5,7,8-tetramethylpyrromethene-BF2 for the preparation of new solid-state laser dyes

The synthesis of 2,6-diethyl-3-methacroyloxymethyl-1,5,7,8-tetramethylpyrromethene-BF₂ (2) was carried out in straightforward fashion from 2,6-diethyl-1,3,5,7,8-pentamethylpyrromethene-BF₂ (1) in three steps. The monomer unit 2 has been shown to be useful for copolymerization with methyl methacrylate for the synthesis of new solid-state optical materials. In addition, the synthesis of 1 has been modified to give greater yields of this useful laser dye. © 1997 John Wiley & Sons, Inc.     

Synthesis,NMR, and Computational Study of 1,2-Diethyl-3-(trimethylsilyl)cyclopropenylium Hexachloroantimonate

Preparation and ¹³C NMR identification of 1,2-diethyl-3-(trimethylsilyl)cyclopropenylium hexachloroantimonate (4) is described. The assignment of the NMR data was corroborated by calculating ¹³C NMR chemical shifts of the corresponding model ion 4M. The total stabilization of the parent cyclopropenylium ion 1 substituted by the silyl and the two methyl groups is found to be only slightly lower than stabilization of the trimethyl derivative. The computed NICS(1) parameters reveal that all of the examined ions possess substantial aromatic character.     

Improved synthesis of V-PYRRO/NO, a liver-selective nitric oxide prodrug, and analogues

The reported synthesis of O²-vinyl 1-(pyrrolidin-1-yl)diazen-1-ium-1,2-diolate (V-PYRRO/NO), a hepatoprotective agent, was cumbersome and limited by a poor overall yield of 4% from sodium 1-(pyrrolidin-1-yl)diazen-1-ium-1,2-diolate (PYRRO/NO). We report an improved synthesis of V-PYRRO/NO in two steps with a significantly higher overall yield of 40% from PYRRO/NO. Using this protocol, a number of structural analogues of V-PYRRO/NO were prepared in good yields.     

Expansion of the pentafluorobenzene ring and other skeletal transformations in the reaction of perfluoro(1,2-diethyl-1-phenyl-1,2-dihydrocyclobutabenzene) with antimony pentafluoride

The reaction of perfluoro(1-phenyl-1,2-diethyl-1,2-dihydrocuclobutabenzene) with SbF5 at 20°C, followed by treatment of the reaction mixture with water gave perfluoro {4-[1-(2-propylphenyl)propylidene]-2,5-cyclohexadien-1-one} together with perfluoro[4b,10-diethylbenzo[a]azulen-7(4bH)-one] resulting from unusual expansion of the pentafluorobenzene ring to seven-membered ring. Analogous reaction at 90°C, apart from the above compounds, afforded perfluorinated 10-ethyl- and 3,10-diethylbenzo[a]azulen-6(10H)-ones via elimination of C₂F₅ group from the seven-membered ring or its migration to the benzene ring.     

Selective mono-fluorination of diols via a cyclic acetal of N,N-diethyl-4-methoxybenzamide

Selective mono-fluorination of 1,2- and 1,3-diols was achieved using N,N-diethyl-4-methoxybenzamide diethyl acetal and Et₃N-3HF. The reaction proceeds through a cyclic acetal of the benzamide, and only one hydroxy group was fluorinated and another one was acylated.     

Adsorption of some functionalized aliphatic compounds on plasma-grown thin-film aluminium and magnesium oxides

A study of the inelastic electron tunnelling (IET) spectra of N,N-diethyl-1,2-diaminoethane, N,N′-diethyl-1,2-diaminoethane, N,N′-dimethyl-1,2-diaminoethane, N,N,N′,N′-tetraethyl-1,2-diamino-ethane and N,N,N′,N′-tetramethyl-1,2-diaminoethane, shows all five systems to form five-membered chelate structures with both nitrogen atoms present in the adsorbate acting as Lewis donors at the same cation on either aluminium oxide or magnesium oxide. The IET spectra for the N-ethyl-2-aminoethanol, N,N-diethyl-2-aminoethanol and N,N-dimethyl-2-aminoethanol also examined indicate that similar alkoxy-amino chelated structures are formed with these adsorbates. For the aminoethanols adsorption—chelation appears to involve adsorbate deprotonation and hydroxyl depletion of the oxide surfaces involved with concomitant binding of the nitrogen atom present to the surface metal ion involved in alkoxide formation.     

Kondesationen mit hydrazin-N,N′-dicarbonsäurediamidin,XXIII [1] fluorierte β-diketone als reaktionspartner

Application of a 30% aqueous potassium carbonate solution for the condensation of 1,2-hydrazinedicaboxamidine with 1,1,1-trifluoro-2,4-pentanedione leads to the formation of 4,4′-dimethyl-6,6′-bis(trifluoromethyl)-2,2′-hydrazopyrimidine, with 1,1,1-trifluoro-2,4-hexanedione to 4,4′-diethyl-6,6′-bis-(trifluoromethyl)-2,2′-hydrazopyrimidine. 2-Guanidinoamino-4-methyl-6-trifluoromethylpyridine formed as an intermediate in this reacton may be isolated, while 4-ethyl-2-guanidinoamino-6-trifluoromethylpyrimidine undergoes cyclization to yield 2-amino-5-ethyl-7-trifluoromethyl-s-triazolo[1,5-a]pyrimidine.     

Synthesis of 1-[6-Fluoro-(2S)-3H,4H-dihydro-2H-2-chromenyl]-(1R)-1,2- ethanediol and 1-[6-Fluoro-(2R)-3H,4H-dihydro-2H-2-chromenyl]- (1R)-1,2-ethanediol

Benzopyran compounds possess diverse pharmacological properties such as β-blockade, anticonvulsant and antimicrobial.[1,2] Our interest has been focused on the synthesis of 1-[6-Fluoro-2S]-3H,4H-dihydro-2H-2-chromenyl]-(1R)-1,2-ethanediol (6) and 1-[6-fluoro-(2R)-3H,4H-dihydro-2H-2-chromenyl]-(1R)-1,2-ethanediol (7) which are particularly convenient precursor to (S,R,R,R)-NE (8). 8 containing four asymmetrical carbon atoms was reported to be the most active isomer.[3] Chandrasekhar[4] has reported on the synthesis of 8. The key step to synthesize this compound is to obtain the chiral chromanone 6 and 7. 6 was accomplished in 8 steps by the Clasien rearrangement and a one-pot Sharpless asymmetric epoxidation, but the compound 7 was accomplished in 10 steps. Johannes[5] used Zr-catalytic kinetic resolution of allylic ethers and Mo-catalyzed chromene formation to synthesize 8 in 14 steps. However both of the methods request many synthetic steps and expensive reagents.     

Synthesis of chiral hydroxyl phospholanes from D-mannitol and their use in asymmetric catalytic reactions

Chiral hydroxyl monophosphane 3 [(2S,3S,4S,5S)-3,4-dihydroxy-2, 5-dimethyl-1-phenylphospholane] and bisphospholanes 5a [1,2-bis[(2S, 3S,4S,5S)-3,4-dihydroxy-2,5-dimethylphospholanyl]benzene] and 5b [1, 2-bis[(2S,3S,4S,5S)-2,5-diethyl-3,4-dihydroxyphospholanyl]benzene] were synthesized from readily available D-mannitol in high yields. Strategies for protection and deprotection of OH-groups in the presence of phosphines have been explored. Rate acceleration in the Baylis-Hillman reaction was observed when a hydroxyl phosphine was used as the catalyst. Rhodium complexes with chiral bisphospholanes are highly enantioselective catalysts for the asymmetric hydrogenation of various kinds of functionalized olefins such as dehydroamino acid derivatives, itaconic acid derivatives, and enamides. An interesting feature of the hydroxyl phospholane system is that hydrogenation of some substrates can be carried out in water with >99% ee and 100% conversion (e.g., itaconic acid).     

2,3-Diferrocenylcyclopropenone in the reaction with organomagnesium compounds

The reactions of 2,3-diferrocenylcyclopropenone with ethyl- and benzylmagnesium chlorides afford 3,3-diethyl- and 3,3-dibenzyl-1,2-diferrocenylcyclopropenes along with products of nucleophilic opening of the three-membered ring: ,-unsaturated and saturated ketones (cis-1,2-diferrocenylpent-1-en-3-one and cis-1,2-diferrocenyl-4-phenylbut-1-en-3-one, 4,5-diferrocenylheptan-3-one, and 3,4-diferrocenyl-1,5-diphenylpentan-2-one). The products of insertion of intermediate diferrocenyl(vinyl)carbene at one of the -bonds of the starting 2,3-diferrocenylcyclopropenone were also isolated: 4-(2-oxo-1-ferrocenylbutyl)- and 4-(2-oxo-3-phenyl-1-ferrocenylpropyl)-2,3,4-triferrocenylcyclobutenones. 3,3-Dibenzyl-1,2-diferrocenylcyclopropene and one of the diastereomers of 4,5-diferrocenylheptan-3-one were studied by X-ray diffraction analysis.     

High-performance liquid chromatographic determination of 1,2-diethyl-3-hydroxypyridin-4-one and its 2-(1-hydroxyethyl) metabolite in rat blood.

A sensitive and selective high-performance liquid chromatographic (HPLC) method for the analysis of 1,2-diethyl-3-hydroxypyridin-4-one (CP94, I) and its 2-(1-hydroxyethyl) metabolite (II) in rat blood is described. I, II and the internal standard, 1-propyl-2-ethyl-3-hydroxypyridin-4-one (CP95, III) were extracted into dichloromethane (3 x 5 ml, with the addition of 1 g of sodium chloride) from blood (0.25 ml plus 0.75 ml of pH 7.0 morpholinopropanesulphonic acid buffer). Extractability approached 100% for I and III, and approximately 65% for II under these conditions. Chromatographic analysis was carried out using a Hypercarb porous graphitised carbon HPLC column (10 cm x 0.46 cm). The mobile phase was 14:86 (v/v) acetonitrile-NaH2PO4 buffer (10 mM, containing 2 mM EDTA, pH adjusted to 3 with phosphoric acid) and detection was by ultraviolet at 280 nm. Calibration curves were linear (correlation coefficient greater than 0.99) and reproducible over the concentration range 0-80 micrograms/ml and the coefficient of variation was less than 16% even at low (1 microgram/ml) concentrations. The minimum quantifiable level was 0.5 microgram/ml for both I and II.     

Synthesis of Novel Poly(aryl ether amide)s Containing the Phthalazinone Moiety

Considerable research has been carried out to develop new condensation polymerscontai- mug heterocyclic units since many of these polymers possess outstandingstrength and moduli and are used predominantly as high temperature-resistant materialsand fibers. Phthalazinone and its derivatives have been known for almost a century'.Recently Hay et ap'3 first reported that phthalazinone and its derivatives were bisphenolIike monomers which can be polymerized with the activated aryl dihalide monomers …     

Stereospecific preparation of (1E,3E,5E)-3.4-difluoro-1,6-diphenylhexatriene and (2E,4E,6E)-diethyl-4,5-difluoroocta-2,4,6-trienedioate

Palladium(0) catalyzed coupling of β-bromostyrene (E/Z = 89/11) with (E)-(1,2-difluoro-1,2-ethenediyl)bis[tributylstannane], 1, in DMF at room temperature stereospecifically gave only (1E,3E,5E)-3,4-difluoro-1,6-diphenylhexatriene. Similarly, palladium(0) catalyzed coupling of (E)-ethyl 3-bromoacrylate as the vinyl halide precursor stereospecifically gave (2E,4E,6E)-diethyl-4,5-difluoroocta-2,4,6-trienedioate. This work demonstrates that a non-fluorine-containing vinyl bromide will selectively undergo coupling with 1 and enable the stereospecific preparation of a mixed polyene system. The (E)-ethyl 3-bromoacrylate coupling with 1 illustrates that mixed functionalized hexatriene systems can be easily accessed via this methodology. The X-ray structure of (2E,4E,6E)-diethyl-4,5-difluoroocta-2,4,6-trienedioate confirmed its structure.     

Some transformations of the substitutive recyclization product obtained from tetrachlorocyclopentadiene dimer and diethylamine

1, 1a,2,3,3a,4,5-Heptachloro-N,N-diethyl-6-oxo-1,1a,3a,6-tetrahydrocyclopropa[c]pentalene-1-carboxamide reacts with hydroxide ion and N-centered nucleophiles following exclusively the Ad_NE scheme with replacement of the 4-chlorine atom. Its reactions with methylmagnesium iodide and diethyl malonate sodium salts involve simultaneous substitution, 1,2-addition at the carbonyl group, and aromatization. Oxidation of 1,1a,2,3,3a,4,5-heptachloro-N,N-diethyl-6-oxo-1,1a,3a,6-tetrahydrocyclopropa[c]pentalene-1-carboxamide with potassium permanganate under conditions of phase-transfer catalysis is accompanied by cleavage of the cyclopentenone fragment with formation of 2,3,4,5,6-pentachloro-6-diethylcarbamoylbicyclo[3.1.0]hex-3-ene-1,2-dicarboxylic acid.     

Expansion of the pentafluorobenzene ring of perfluoro-1,2-diethyl-1-phenylbenzocyclobutene under the action of SbF5

Perfluoro-1,2-diethyl-1-phenylbenzocyclobutene under the action of SbF₅ gives, after treatment of the reaction mixture with water, perfluoro-4-[1-(6-propyl-phenyl)-propylidene]cyclohexa-2,5-dienone along with the products of unusual pentafluorobenzene ring expansion - perfluorinated 4b,10-diethylbenzo[a]azulen-7(4bH)-one and 10-ethylbenzo[a]azulen-6(10H)-one.