Synthesis of benzophenone tetracarboxylic dianhydride and pyromellitic dianhydride incorporated biscitraconimides and their thermal polymerization

Biscitraconimides incorporated with 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and pyromellitic dianhydride (PMDA) were synthesised. Their curing behavior as well as thermal stabilities were investigated. The intermediate amic acids were prepared by the reaction of 4-amino 4′-citraconamic acid diphenyl sulphone, 4-amino 4′-citraconamic acid diphenyl ether, and 12-amino 1-citraconamic acid dodecane with BTDA and PMDA, respectively. Six amic acids formed were then imidized by cyclocondensation with acetic anhydride. The imide monomers were obtained and these were cured at 225–240°C. The thermal stabilities of the polymers so formed were investigated and compared. © 1996 John Wiley & Sons, Inc.     

The synthesis of anthracyclinones-ii : The synthesis of 7,9-bisdeoxycarminomycinone and -daunomycinone

7,9-Bisdeoxycarminomycinone has been synthesised from 5-hydroxyquinizarin by two annelation routes involving nitronate addition to C-2 and aldol condensation at C-3. 4-Demethoxy-7,9-bisdeoxydaunomycinone has been synthesised efficiently by similar methods.     

The synthesis of ferrocenyl- and ferrocenoylpyrimidines

New derivatives of pyrimidine were synthesized from ferrocenyl ketones by the reactions of [3+1+1+1]annulation and intermolecular cyclization. The electrochemical behavior of the obtained compounds was studied by the method of cyclic voltammetry. All the compounds may be characterized with the signal, corresponding to the reversible one-electron transfer in ferrocene-ferrecinium and lowering of the redox potential with respect to ferrocene.     

The synthesis of naphthothiopyranopyranones and naphthothiopyranopyranthiones

The synthesis of fused tetracyclic naphthothiopyranopyranones from dihydronaphthothiopyranones I or II has been studied. Compounds I or II have been cyclised in good yield to the corresponding dioxaborin difluoride complexes III, IV, XIII and XIV by treatment with acetic or propionic anhydride and boron trifluoride etherate. These complexes and the Vilsmeier reagent reacted to produce fused tetracyclic 3-substituted naphthothiopyranopyranones V, VI, XV or XVI . The reaction of dioxaborin difluoride complexes III or IV with dimethylthioformamide (DMTF) afforded dimethylaminovinyldioxaborin difluoride complexes IX or X . Treatment of IX or X with hydrochloric acid solution gave naphthothiopyranopyranones VII or VIII . The reaction of VII, VIII, XV or XVI with DMTF/acetic anhydride yielded new products, which was identified as naphthothiopyranopyranthions XI, XII, XVII or XVIII .     

The synthesis and characterization of telluranthrene

The reaction between o-phenylenemercury and finely powdered tellurium metal at temperatures not exceeding 250°C yields a pale yellow crystalline solid. Characterization of this solid by elemental analysis, determination of the molecular mass, mass spectral analysis, and ¹³C and ¹²⁵Te NMR spectral analysis indicates that it is the hitherto uncharacterized telluranthrene.     

The structure and synthesis of xanthomicrol

Xanthomicrol is shown to be 5,4′-dihydroxy-6,7,8-trimethoxyflavone by a combination of physical and degradative methods. Its synthesis from pentamethoxybenzene is described.     

The synthesis and structure of triphenylsiloxycyclotriphosphazenes

The triphenylsiloxy-substituted cyclotriphosphazenes, N₃P₃Cl₅OSiPh₃, gem-N₃P₃Cl₄(OSiPh₃)₂, N₃P₃(OSiPh₃)₆, and N₃P₃(OPh)₅OSiPh₃, have been prepared. The synthesis of gem-N₃P₃Cl₄(OSiPh₃)₂ involves the reaction of (NPCl₂)₃ with Ph₃SiONa to form the intermediates gem-N₃P₃Cl₄(OSiPh₃)₂(ONa) and gem-N₃P₃Cl₄(ONa)₂, which yield gem-N₃P₃Cl₄(OSiPh₃)₂ when treated with Ph₃SiCl. The compounds N₃P₃Cl₅OSiPh₃ and N₃P₃(OSiPh₃)₀ are formed by the condensation reactions of N₃P₃Cl₅OBuⁿ and N₃P₃(OBuⁿ)₆, respectively, with Ph₃SiCl. The compound N₃P₃(OPh)₅OSiPh₃ is synthesized by the reaction between N₃P₃(OPh)₅Cl and Et₃SiONa to first give the intermediate N₃P₃(OPh)₅ONa, which yields N₃P₃(OPh)₅OSiPh₃ when reacted with Ph₃SiCl. The structural characterization and properties of these compounds are discussed. The crystal and molecular structure of gem-N₃P₃Cl₄(OSiPh₃)₂ has been investigated by single-crystal X-ray diffraction techniques. The crystals are monoclinic with the space group P2₁/c with a = 16.850(8), b = 12.829(4), c = 18.505(15) Å, and β = 101.00(6)° with V = 3927 ų and Z = 4. © 1996 John Wiley & Sons, Inc.     

The synthesis and reactivity of rhenocene

Oxidation of lithiodicyclopentadienylrhenium by organic carbonyl compounds gives the complex (C₂₀H₂₀Re₂). Spectroscopic data show that this complex consists of two rhenocene fragments, {(C₅H)₅Re}, linked by a metal-metal bond, and so that it must be represented as a dimer of rhenocene, {(C₅H₅)Re}₂. Reaction of the dimer with benzyl bromide gives {(C₅H₅)₂ReCH₂C₆H₅} and {(C₅H₅₂ReBr}, while thermolysis gives the new dimeric complex {(C₅H₅)₂(C₅H₄)₂Re₂} and two equivalents of {(C₅H₅)ReH} and photolysis (λ ? 410 nm) gives [{η⁴- (C₅H₆)(C₅H₅)Re}{η⁵,η¹-(C₅H₄)(C₅H₅)Re}].     

The synthesis and characterization of norbornylsilasesquioxanes

Norbornene reacts with trichlorosilane to generate norbornyltrichlorosilane in high yield. The slow hydrolysis of norbornyltrichlorosilane in acetone yields incompletely condensed norbornyl-silasesquioxanes. The compound C₄₂H₇₀O₁₁Si₆ can be isolated from this reaction. On the basis of elemental analyses, ¹H, ¹³C and ²⁹Si NMR, mass spectroscopy, infrared spectroscopy, and crystallographic analysis, C₄₂H₇₀O₁₁Si₆ is formulated as [(C₇H₁₁)₆Si₆O₇(OH)₄], with the Si₆O₇ framework being composed of two perpendicular Si₄O₄ planes sharing an edge. [(C₇H₁₁)₆Si₆O₇(OH)₄] is a putative model of vicinal [Si(OH)]₂ sites on the surface of partially dehydroxylated silica.     

The structure and synthesis of alliodorin

A new phenolic terpene aldehyde, alliodorin (1a), has been isolated from Cordia alliodora and shown to be a derivative of geranylhydroquinone. Alliodorin diacetate was synthesized by geranylation of hydroquinone followed by acetylation and finally by oxidation with selenium dioxide, thus confirming the assigned structure. Several other compounds from the oxidation reaction were isolated and characterized.     

The synthesis and rearrangement of epoxypyrones

The oxidation of 5-acyl-4-oxo-pyran-2-carboxylic acid esters $\text{1}$,$\text{2}$ to novel epoxypyrones and subsequent rearrangement to the previously inaccessible 6-substituted-5-hydroxy or 5-chloropyrones $\text{6}$ - $\text{9}$ are described.     

The synthesis of metacycloprodigionsin

Metacycloprodigiosin 1, a tripyrrole pigment isolated from Streptomyces longisporus ruber, has been synthesized by condensation of the meta-fused pyrrole 2, prepared from cyclododecanone, with the known methoxybipyrrole aldehyde precursor 3.     

The synthesis of vinylpyrrolidone

Summary The synthesis of vinylpyrrolidone from succinic acid was accomplished without the use of acetylene or increased pressure.