Synthesis of (1,3-adamantylene)bis-1,3-dicarbonyl compounds

Reactions of 1,3-dihydroxyadamantane with 1,3-dicarbonyl compounds in the presence of 5 mol % of In(OTf)₃ afforded a series of (1,3-adamantylene)bis-1,3-dicarbonyl compounds in yields of 25–83%.     

Stannoboroxanes : III. Synthesis and reactions of 1,3-bis(boryloxy)tetraalkyldistannoxanes and related compounds

1,3-Bis(boryloxy)tetraalkyldistannoxanes,

, R = Me, Bu; G = CMe₂CH₂CHMe—, —CMe₂ —CMe₂ — and —CHMe—CH₂ — have been prepared from dialkyltin oxide and pyroborate, or directly from dialkyltin oxide, boric acid and glycol. A dimeric structure for these compounds is proposed on the basis of molecular weight, IR and PMR studies. The reactivity of the SnOB bond towards PhNCO and Me₃SiCl has been demonstrated.     

Retention of 1,ω-bis-(dialkylamino)-polysulphides and related compounds in reversed-phase HPLC

Summary The reaction of secondary amines R₂NH with disulfur dichloride S₂Cl₂ in dichloro methane yields mixtures of bis-dialkylamino polysulphides R₂N–S_n–NR₂ with sulphur chain lengths varying from n_s=2 to 14. The S chains are believed to be non-branched. The compounds form homologous series in each of which sulphur atoms give a constant contribution to retention. The sulphur retention index depends slightly on the carbon number in the terminal alkyl groups R. The presence of nitrogen lowers retention. The index increment of N is ca. –160 units, which is distinctly less negative than values found in alkylamines.     

Darstellung und reaktionen von 1,3-bis-(trimethylsiloxy)-isobenzofuranen

1,3-Bis-(trimethylsiloxy)-isobenzofuran ($\text{2a}$) can be prepared from dihydro phthalic anhydride. It is not stable under the reaction conditions but can be trapped with dienophiles. The tetraphenyl derivative $\text{2b}$ showed to be more stable towards protonation.     

Synthesis and properties of z-1,3-bis-(aryl)-4-bromo-2-buten-1-ones

Bromination of 1,3-bis(aryl)-2-buten-1-ones by N-bromosuccinimide in anhydrous carbon tetrachloride gives Z-1,3-bis(aryl)-4-bromo-2-buten-1-ones. The effect of the nature of substituent in the benzene ring on the course of a reaction with nucleophiles has been studied. Heating an alcohol solution of these ketones (Ar = 4-MeOC₆H₄, 4-ClC₆H₄) in the presence of acid or in the presence of base (Ar = Ph) gave 2,4-bis(aryl)furans. Treatment of 1,3-bis(aryl)-4-bromo-2-buten-1-ones with thioacetamide gave 2,4-bis(aryl)thiophenes. The oxidation of the halo-substituted dypnones with H₂O₂/NaOH gave (3-bromomethyl-3-aryl-2-oxiranyl)(aryl)methanones. The reaction of halo-substituted dypnones with aryl hydrazines gave 1,3,5-triaryl-1,6-dihydropyridazines or 1,3,5-triarylpyridazinium bromides depending on the structure of the reagents.     

Synthesis of heterocyclic compounds from cyclohexane-1,3-diones (review)

The literature data on the synthesis of partially hydrogenated heterocyclic compounds containing a 3-oxocyclohexene structural fragment condensed with five-, six-, or seven-membered oxygen-, nitrogen-, and sulfur-containing heterorings from cyclohexane-1,3-diones and their derivatives are examined in this review.     

Synthesis of 2,3-disubstituted-1,3-oxazolidines

A series of 2-aryl-3-alkyl or aryl carbamoyl- and thiocarbamoyl-1,3-oxazolidines was prepared by the reactions of alkyl and aryl isocyanates and isothiocyanates with N-(2-hydroxyethyl)-benzalamincs. The nuclear magnetic resonance spectra of these compounds are discussed.     

Synthesis and properties of air-stable 1,3-diphosphacyclobutane-2,4-diyls and the related compounds

A kinetically stabilized phosphaalkyne bearing a bulky Mes^∗ (2,4,6-tri-t-butylphenyl) group is useful compound to prepare an enormous number of highly stable 1,3-diphosphacyclobutane-2,4-diyls through reactions with a lithium reagent and an electrophile. By utilizing this synthetic protocol, we prepared several non-symmetrical 1,3-diphosphacyclobutane-2,4-diyls in which the substituents on the phosphorus are different. Furthermore, we succeeded in preparation and characterization of novel air-tolerant symmetrical 2,4-bis(2,4,6-tri-t-butylphenyl)-1,3-diphosphacyclobutane-2,4-diyls bearing the identical alkyl substituents on the phosphorus atoms. Structures and properties of the 1,3-diphosphacyclobutane-2,4-diyls indicate characters as singlet ground-state carbon centered biradicals. In addition to those biradicals, we succeeded in preparation and isolation of a novel P-heterocyclic air-stable neutral radical as well as a P-heterocyclic cation radical.     

Facile Synthesis of 1,2-bis-(Cyanomethyl)Benzenes

3-Alkoxy-1,2-bis-(cyanomethyl)benzenes can be prepared in two steps, in high yield, from m-alkoxy-N.N-dimethylbenzylamines by directed metallation followed by ethyl chloroformate-promoted cyanide displacement.     

Electron-impact fragmentations of 1,3- and 1,4-bis-(cyclopentadienyliron dicarbonyl)tetrafluorobenzenes

Although 1,4-bis(cyclopentadienyliron dicarbonyl)-tetrafluorobenzene fragments under electron-impact, losing four CO groups stepwise prior to other observed fragmentations, the corresponding 1,3-derivative eliminate HF after loss of only two CO groups.     

Oxidation of Poly(2,3-dimethylbutadiene-1,3)

Abstract

Poly(2,3-dimethylbutadiene-1,3) containing cis-1,4, trans-1,4, and 1,2 structural units in various proportions undergoes rapid oxidation even at room temperature. The process of oxidation is accompanied by cyclization. The concentration of peroxides that form at room temperature is relatively very high, reaching the value of one peroxidic group per 16 monomeric units. The formation of six-membered rings involving the peroxidic bonds in poly(2,3-dimethylbutadiene) is accompanied by degradation.     

Hydrophile-lipophile balance for 1,3-bis-(Ω-alkoxy-oligooxyethylene)-propan-2-ols

The effective hydrophile content and hydrophile-lipophile balance were determined for l,3-bis-(-alkoxy-oligooxyethylene)-propan-2-ols using retention data of standard alcohols and alkanes determined by gas chromatography. The effect of standard surfactants, polar solutes and polarity parameters on the hydrophile balance was discussed. From the effective hydrophile content (E _e), the HLB values could be estimated asE _e/5.     

Synthesis and Properties of 2,3-Diethynyl-1,3-Butadienes

The first general preparative access to compounds of the 2,3-diethynyl-1,3-butadiene (DEBD) class is reported. The synthesis involves a one-pot, twofold Sonogashira-type, Pd⁰-catalyzed coupling of two terminal alkynes and a carbonate derivative of a 2-butyne-1,4-diol. The synthesis is broad in scope and members of this structural family are kinetically stable enough to be handled using standard laboratory techniques at ambient temperature. They decompose primarily through heat-promoted cyclodimerizations, which are impeded by alkyl substitution and accelerated by aryl or alkenyl substitution. An iterative sequence of these unprecedented Sonogashira-type couplings generates a new type of expanded dendralene. A suitably substituted DEBD carrying two terminal alkyne groups undergoes Glaser–Eglinton cyclo-oligomerization to produce a new class of expanded radialenes, which are chiral due to restricted rotation about their 1,3-butadiene units. The structural features giving rise to atropisomerism in these compounds are distinct from those reported previously.     

Photocationic crosslinking of poly(2,3-epithiopropyl methacrylate) and photo-initiated cationic polymerization of its model compounds

Photocationic crosslinking of a poly(2,3-epithiopropyl methacrylate) (PETMA) film containing 4-N,N-diethylaminobenzene diazonium tetrafluoroborate (DAC) was investigated. Very rapid photocrosslinking of PETMA was observed and the rate was greater than that of poly(glycidyl methacrylate) with DAC. Post-heating of the irradiated PETMA film resulted in a decrease of the insoluble fraction. This decrease was explained by scission of crosslinking points by the BF₃. In the present conditions, more than 0.3 wt % of DAC was required to insolubilize the PETMA film. Photopolymerizations of propylene sulfide (PS) and 2,3-epithiopropyl pivalate (ETPP) in the presence of DAC were investigated. The polymerization of PS proceeded smoothly but addition of ethyl acetate to PS depressed the rate and the degree of polymerization. ETPP could not be polymerized but copolymerized with PS by this method. Addition of ETPP to PS depressed both the rate of the polymerization and the degree of polymerization. From these results, it is deduced that the photocrosslinking of a PETMA film is caused by a cationic polymerization of episulfide groups but the chain length is not large.     

Synthesis and cationic polymerization of substituted 2,3-dihydrofurans

Cationic polymerization of substituted 2,3-dihydrofurans has been performed to investigate the substituent effect on the ring-opening polymerization. 2-Phenyl-2,3-dihydrofuran ( III ), 2-methoxy-5-phenyl-2,3-dihydrofuran ( V _a), and 2-ethoxy-5-phenyl-2,3-dihydrofuran ( V _b) were synthesized and polymerized with BF₃ etherate and AlCl₃ as acid catalysts. V _a and V _b ring-opening polymerized well to give the polymers with benzoyl as pendant group which were formed via cationic rearrangement during the ring-opening process, while III polymerized via simple opening of ethylenic double bond to form a polymer with the retention of tetrahydrofuran ring in the main chain. The nature of substituted cyclic vinyl ethers depending on substituents was also discussed.     

1,3-dipolar cycloaddition of methyl 3-(1-imidazolyl)acrylate and related compounds

The 1,3-dipolar cycloaddition reaction of 1-vinylimidazole and β-(1-imidazolyl)-α,β-unsaturated carboxylic esters with N.α-diphenylnitrone and acetonitrile oxide was carried out and compared with those of β-pyrrolidinyl- and β-phenyl-α,β-unsaturated carboxylic esters. The imidazolyl moiety bonded to olefinic double bond was suggested to have properties intermediate to pyrrolidinyl and phenyl groups.     

Synthesis of regiocontrolled poly(4,6-di-n-butoxy-1,3-phenylene) by oxidative coupling polymerization

Poly(4,6-di-n-butoxy-1,3-phenylene) ( 6 ) was prepared by oxidative coupling polymerization of 1,3-di-n-butoxybenzene ( 1 ) or 2,2′,4,4′-tetra-n-butoxy biphenyl (3). Polymerizations were conducted in nitrobenzene in the presence of FeCl₃ at room temperature and produced polymers with number-average molecular weights up to 42,000. The effects of various factors, such as amount of FeCl₃ and reaction temperature and time were studied. The structure of polymer 6 was characterized by 270 MHz ¹H- and 68.5 MHz ¹³C-NMR spectroscopies and was estimated to consist of almost completely 1,3-linkage. The regiocontrolled polymer was readily soluble in common organic solvents. Thermogravimetric analysis of polymer 6 showed 10% weight loss at 390°C in nitrogen. © 1997 John Wiley & Sons, Inc. J Polym Chem 35 : 2259–2266, 1997     

Novel synthesis of a potentially trinucleating ligand: 1,3-bis-(2-hydroxyphenyl)-1,3-propanedione

Reaction of 1,3-bis-(2-hydroxyphenyl)-1,3-propanedione (H₃L), a ligand with three possible sites of coordination acting as a chelating agent, with metal acetates results in the formation of mononuclear species M(H₂L)₂·S,S′ (M = Zn, Cu, Co; S,S′ = solvent or water molecules). A compound of general formula NEt₄[Li(H₂L)₂] is obtained upon reaction of Zn(H₂L)₂·S,S′ with excess of lithium ethanolate. Further reaction of the mononuclear species with excess of the appropriate metal acetate yielded di- or trinuclear complexes depending upon the metal used. Due to the different coordination sites of H₃L it is expected that trinuclear complexes of the types A₃, A₂B or AB₂ will be obtained. Examples of the types A₃ and A₂B are reported.