Metal(II) 4,4′,4″,4′″-phthalocyanine tetramines as curing agents for heat resistant epoxy formulations

Pure metal(II) 4,4′,4″,4′″-phthalocyanine tetraamines (MPTA) have been used to cure epoxy resins in a homogeneous reaction. Infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analytical studies were used to characterize these materials and to evaluate the optimum curing conditions. Considerable improvement in the heat resistance of the epoxy resin cured with MPTA over those cured with other commonly used curing agents was observed. This was expected from the highly aromatic structure of the phthalocyanines. A noteworthy feature of these cured materials is their high anaerobic char yield, 73.5–75%, higher than in any heretofore known cured epoxy systems. Preliminary mass spectral studies on the cured polymers are presented.     

Partial Synthesis of 3′-Hydroxy-2′-deoxy-2″,3″,4″,5″-tetrahydroverrucarin A. Verrucarins and roridins, 38th Communication [1]

The macrocyclic trichothecene triester 3′-hydroxy-2′-deoxy-2",3",4",5"-tetrahydroverrucarin A ( 37 ), has been synthesized starting from the sesquiterpene alcohol verrucarol ( 3 ), adipic acid and a derivative of mevalonic acid ( 14 ). The latter has been prepared from 4-(tetrahydro-2-pyranyloxy)-2-butanone ( 9 ).     

4,4′,4″-Tris(5-nonyl)-2,2′ : 6′,2″-terpyridine as ligand in atom transfer radical polymerization (ATRP)

The bulk atom transfer radical polymerization (ATRP) of styrene or methyl acrylate was carried out in the presence of CuCl or CuBr complexed by equimolar amounts of 2,2′: 6′,2″-terpyridines (tpy) as ligands. Uncontrolled reactions were observed in the presence of unsubstituted ligands whereas relatively fast but controlled polymerization of styrene and methyl acrylate was observed for CuCl and CuBr complexed by tpy with three 5-nonyl substituents (tNtpy). Molecular weights evolved linearly with conversion and polymers with relatively low polydispersities were formed (M_w/M_n < 1.2).     

Chemical behaviours of 3-[1′-chloro-3′-(2″-phenyl-1″,3″-oxazol-5″-one=4″-ylidene)propen-1′-yl]coumarin towards some nucleophilic reagents

The chemical behaviours of 3-[1′-chloro-3′-(2″-phenyl-1″,3″-oxasol-5″-one-4″-ylidene)-propen-1′-yl]coumarin towards nucleophilic reagents (such as hydrolysis, aminolysis, hydroxyl-aminolysis, methanolysis and hydrazinolysis) were described.     

Die Chelatbildung von N-Tris(2-aminoethyl)amin-N′,N′,N″,N″,N‴,N‴-hexaessigsäure (H6TTAHA) und N-(Pyrid-2-yl-methyl)ethylendiamin-N,N′,N′-triessigsäure (H3PEDTA) mit Gadolinium(III) – Synthesen,Komplexstabilität und NMR-Relaxivität

Chelate Formation of N-Tris(2-aminoethyl)amine-N′,N′,N″,N″,N?,N?-hexaacetic Acid (H₆TTAHA) and N-(Pyrid-2-yl-methyl)ethylenediamine-N,N′,N′-triacetic Acid (H₃PEDTA) with Gadolinium(III) – Syntheses, Stability Constants, and NMR-Relaxivities The chelate formation of N-tris(2-aminoethyl)amine-N′,N′,N″,N″,N?,N?-hexaacetic acid (H₆TTAHA) and N-(pyrid-2-yl-methyl)ethylenediamine-N,N′,N′-triacetic acid (H₃PEDTA) with gadolinium(III) has been studied potentiometrically in aqueous solution at 25°C and μ = 0.1 (KCl). [Gd(TTAHA)]^3?: 1gβ_M/ML = 19.0; {H[Gd(TTAHA)]}^2?: 1gK_H/MHL = 8.30; [Gd(PEDTA)]: 1gβ_M/ML = 15.56. Both 1 : 1 gadolinium(III) complexes were isolated as Na₂H[Gd(C₁₈H₂₄N₄O₁₂)] · 3.5 H₂O and [Gd(C₁₄H₁₆N₃O₆)] · 3 H₂O, respectively. Their ¹H-NMR relaxivities [1 · mmol^?1 · s^?1] ({H[Gd(TTAHA)]}^2?: 9.5; [Gd(PEDTA)]: 8.8) offer promising applications for ¹H-NMR imaging.     

Polyamide-imides from 3′,4′-dicarboxy-4″-chloroformyl terephthaloylphenone anhydride

Novel polyamide-imides were prepared from 3′,4′-dicarboxy-4″-chloroformyl terephthaloylphenone anhydride and various aromatic and aliphatic diamines. The polymers were characterized by viscosity, infrared spectra, TGA, DSC, and elemental analysis. The thermal stability of the films was comparable to that of polyamide-imides previously reported.     

Chemistry of the phenoxathiins. III. Synthesis of benzo[1″,2″:5,6:5″,4″:5′,6′]bis[1,4]oxathiino[3,2-b:3′,2′-b']dipyridine

As a result of studies dealing with the synthesis of 1-azaphenoxathiins, the synthesis of benzo[1″,2″:5,6:5″,4″:5′,6′]bis[1,4]oxathiino[3,2-b:3′,2′-b']dipyridine was examined. Unique evidence of solvent participation in the synthesis of these compounds by the structure elucidation of a novel minor by-product formed during the synthesis of the title compound is also reported.     

Synthese,Struktur und einige Reaktionen [N-(N′,N′,N″,N″-tetramethyl)-guanidinyl]-substituierter Phosphorylverbindungen

Synthesis, Structure, and some Reactions of N-(N′,N′,N″,N″-tetramethyl)guanidinyl-substituted Phosphoryl Compounds The tetramethylguanidinyl-substituted phosphoryl compounds 1 – 10 were prepared in the reaction of the appropriate chlorophosphoryl compounds with either N′,N′,N″,N″-tetramethylguanidine (HTMG) or N-trimethylsilyl-(N′,N′,N″,N″-tetramethyl)guanidine (TMSTMG). With methyl iodide 1 reacted with N-alkylation to give the ammonium salt 11. 1 reacted with BF₃ · Et₂O at both imino nitrogen atoms with formation of the bis-BF₃-adduct 12 . The X-ray structure determination of phenylphosphonic acid-bis(N′,N′,N″,N″-tetramethylguanidinide) 3 shows shortened PN-bonds and widened PNC-angles, consistent with the partial double bond character of the PN-bond.     

Micromodulation of electron-transfer rates in mixed-valence 1′,1″′-dibenzylbiferrocenium cations

X-Ray structures of 1′,1′″-disubstituted biferrocenium triiodide salts have been studied and the dramatic effects of substituents on the intramolecular electron-transfer rates are described.     

Kinetik und stereochemischer Verlauf der thermischen Umlagerung der vier stereoisomeren Propenyl-(but-2′-enyl)-äther

The gas-phase rearrangement of (1Z, 2′E)-, (1Z, 2′Z)-, (1E, 2′E)-, and (1E, 2′Z)- propenyl but-2′-enyl ether (Z, E)-, (Z, Z)-, (E, E)-, and (E, Z)-1) into erythro- and threo-2, 3-dimethyl-pent-4-en-al (erythro- and threo-2) was investigated over a temperature range from 142,5° to 190,0° at 20–35 Torr (for kinetic data and activation parameters see table 2). All four stereoisomeric ethers 1 rearrange preferentially via a chair-like transition state C into the aldehydes 2 (ΔΔG^≠ (160°) = 2,5–2,7 kcal/mol for B – C (B = boat-like transition state). The relative rates (k_rel) for (Z, Z)-1, (Z, E)-1, (E,Z)-1, and (E,E)-1 at 160° are 1,0, 2,9, 4,3 and 9,0 respectively (see table 5). Taking into account the relative enthalpies of the ethers 1 and the steric interaction in the C transition state of the ethers 1 (see table 6), k_rel values can be estimated. They are in good agreement with those observed (see table 5).     

Angiotensin-II Analogues. I: Synthesis and incorporation of the halogenated amino acids 3-(4′-iodophenyl)alanine, 3-(3′,5′-dibromo-4′-chlorophenyl)alanine, 3-(3′,4′,5′-tribromophenyl)alanine,and 3-(2′,3′,4′,5′,6′-pentabromophenyl)alanine

The synthesis of the polyhalogenated phenylalanines Phe(3′,4′,5′-Br₃) ( 3 ), Phe(3′,5′-Br₂-4′-Cl) ( 4 ) and DL -Phe (2′,3′,4′,5′,6′-Br₅) ( 9 ) is described. The trihalogenated phenylalanines 3 and 4 are obtained stereospecifically from Phe(4′-NH₂) by electrophilic bromination followed by Sandmeyer reaction. The most hydrophobic amino acid 9 is synthesized from pentabromobenzyl bromide and a glycine analogue by phase-transfer catalysis. With the amino acids 4, 9 , Phe(4′-I) and D -Phe, analogues of [1-sarcosin]angiotensin II ([Sar¹]AT) are produced for structure-activity studies and tritium incorporation. The diastereomeric pentabromo peptides L - and D - 13 are separated by HPLC. and identified by catalytic dehalogenation and comparison to [Sar¹]AT ( 10 ) and [Sar¹, D -Phe⁸]AT ( 14 ).     

Isomerisierung bei der Komplexbildung von 3-Acetyl-tetramsäure: Struktur und magnetische Eigenschaften des CuII- und NiII-Komplexes von 2,7-Bis(1′, 5′, 5′-trimethylpyrrolidin-2′, 4′-dion-3′ -yl)-3, 6-diazaocta-2, 6-dien

Isomerization at the Complexation of 3-Acetyltetramic Acid: Structure and Magnetic Properties of the Cu^II- and Ni^II-Complex of 2,7-Bis (1′, 5′, 5′ -trimethylpyrrolidin-2′,4′ -dion-3′ -yl)-3,6-diazaocta-2,6-dien 2,7-Bis(1′, 5′, 5′ -trimethylpyrrolidin-2′, 4′ -dion-3′ -yl)-3,6-diazaoctadien formes Cu^II and Ni^II complexes with different constitutions (because of the Z/E isomerization). Results of X-ray analysis of N,N′ -ethylenbis(1′, 5′, 5′ -trimethylpyrrolidin-2′, 4′ -dion-3′ -acetiminato)nickel(II) 1 respectively -copper(II) 2 shows, that the complexing agent in 1 occurs in the E-form, whereas the ligand of the Cu^II complex forms the Z-form. Magnetic susceptibility and shift effects of the ¹³C-NMR signals point to a weak paramagnetism of the Ni^II complex. ESR-spectra are obtained from 2 only. Furthermore, the Cu^II complex reduces the relaxation times T₁ and T₂ of ¹H and ¹⁷O nuclei spins from water. From the temperature dependence of the shortening of the relaxation times an activation energy is calculated which describes the reorientation of the copper complex in the “water matrix”.     

Synthesis of new heteroaromatic nitrogen ligands: Pyrimido‐[4″,5″:4′,5′]‐thieno[3′,2′:4,5]thieno[3,2‐d]pyrimidines and 1,2,3‐triazine[4″,5″:4′,5′]thieno[3′,2′:4,5]thieno[3,2‐d]‐1,2,3‐triazines

An efficient one‐pot access for the synthesis of the previously unreported tetracyclic fused pyrimido‐[4″,5″:4′,5′]thieno[3′,2′:4,5]thieno[3,2‐d]pyrimidine ( 3 ) and 1,2,3‐triazine[4″,5″:4′,5′]thieno‐[3′,2′:4,5]thieno‐[3,2‐d]‐1,2,3‐triazine ( 5 ) heteroaromatic nitrogen ligands is described. The title compounds 3 and 5 were obtained from 3,4‐diaminothieno[2,3‐b]thiophene‐2,5‐dicarbonitrile and phosgeniminium chloride and sodium nitrite/HCl, respectively. Substituted condensed thieno[2,3‐b]thiophene derivatives 4 and 6 were synthesized by nucleophilic displacement of the chloroderivatives 3 and 5 .     

Curing of epoxy resins with metal(II)4,4′,4″,4‴-tetraamino phthalocyanines-modification with elastomers

The use of metal phthalocyanine tetraamines in curing epoxy resins to form high-temperature-resistant matrix polymers for composites has been reported earlier. The effect of adding carboxy-terminated butadiene-acrylonitrile (CTBN) elastomer is now described; preliminary measurements of tensile, flexural, and short-beam shear strengths, dynamic moduli, resin content, and moisture absorption are presented, and the results of dynamic thermogravimetric analyses are given. In addition to their high char yield (86–87.5% at 800°C in a nitrogen atmosphere) and limiting oxygen index (48.3–50.3), the laminates showed good mechanical properties.     

Synthese und Reaktionen von Metallkomplexen mit porphinoidem Ligandsystem 1. Mitteilung (3,3,4,4-Tetramethyl-5-imino-1-pyrrolin-2-yl)-(3′,3′,4′,4′-tetramethyl-5′-iminopyrrolidin-2′-yliden)-methan,ein Zwischenprodukt zur Synthese von Hexahydroporphinen

Reaction of tetramethylsuccinicdinitrile with methylmagnesium iodide in boiling toluene leads to the title compound 8 in 80–85% yield. The magnesium complex of 2-imino-3,3,4,4-tetramethyl-5-methylidene-pyrrolidine is shown to act as an intermediate.     

Chemistry of the phenoxathiins VIII. Synthesis of 7-chlorobenzo[1″.2″:5,6:3″,4″:5′,6′] bis[1,4] oxathiino[3,2-b:3′.2′-b′]dipyridine

As a continuation of recent study on the synthesis of a bis[1,4]oxathiinodipyridine ring system, we would now like to report the preparation of 7-chlorobenzo[1″,2″:5,6:3″,4″:5′,6′]-bis[1,4]oxathiino[3,2-b: 3′,2′-b]dipyridine. Although a potentially complex reaction with several products possible, the title compound was formed exclusively, suggesting considerable mechanistic selectivity. The characterization of the product by FT-¹H-nmr as well as its mass spectral fragmentation pathways are also reported.