Phospha-S-triazines. VIII. Chloro-substituted diphospha-S-triazines

1,3-Bis(phenylchlorophospha)-5-perfluoroalkyl-2,4,6- triazine and the corresponding perfluoroalkylether analogue were synthesized by interaction of equimolar amounts of the respective amidines and imido-diphenyl-diphosphinic acid pentachloride. With additional quantities of amidine, 1,3-bis(phenylperfluoro-$\text{n}$-octanoylamidinophospha)-5-perfluoro- $\text{n}$-heptyl-2,4,6-triazine was obtained. The replacement of the chloro- by azido-groups in 1,3-bis(phenylchlorophospha)-5- perfluoro-$\text{n}$-heptyl-2,4,6-triazine proceeded readily. The mass spectral breakdown patterns of the chloro- and the amidino- substituted compounds were directly comparable to those of the bis(diphenylphospha)-s-triazines.     

Diphosphatetraazacyclooctatetraenes. II. Properties and degradations

1,5-Bis(diphenylphospha)-3,7-bis(perfluoroalkylether)-2,4,6,8- tetraazacyclooctatetraene and 1,3-bis(diphenylphospha)-5,7-bis(perfluoroalkylether) -2,4,6,8-tetraazacyclooctatetraene were found to decompose at 316°C to phospha-s-triazines. The symmetrical arrangement liberated perfluoroalkylether nitrile with concommitant formation of the corresponding diphospha-s-triazine; the unsymmetrical isomer eliminated the (C₆H₅)₂PN unit to give the monophospha-s-triazine. The thermal and oxidative stabilities of the two compounds differed widely, with the unsymmetrical isomer being significantly more stable than the symmetrical arrangement. Spectral data pertinent to these results are discussed. Both materials were found to be effective in arresting perfluoroalkylether fluid degradation in oxidizing atmospheres in the presence of metal alloys.     

Phospha-s-triazines. I. Syntheses and properties of mono(diarylphospha)-s-triazines

A series of monophospha-s-triazines, namely l-diphenylphospha-3,5-bis(perfluoro-n-heptyl)-2,4,6-triazine, 1-diphenylphospha-3,5-bis[C₃F₇-[OCF(CF₃)CF₂]_xOCF(CF₃)]-2,4,6-triazine (x = 1 and 2), and the penta-fluorophenyl-substituted analogues were prepared, in yields of 50-75%, from the respective imidoylamidines and trichlorophosphoranes. The physical properties of the corresponding phenyl and pentafluorophenyl monophospha-s-triazines did not differ significantly; the perfluoroalkyl-substituted materials were low melting solids whereas the perfluoroalkyl-ether-containing compositions were liquids. Preliminary degradative studies showed these compounds to be thermally and oxidatively stable. The l-diphenylphospha-3,5-bis[C₃F₇OCF(CF₃)CF₂OCF(CF₃)]-2,4,6-triazine was found to be an effective anti-corrosion additive for perfluoroalkylether type fluids.     

Syntheses and degradations of fluorinated heterocyclics

Tris (perluoro-n-heptyl)-s-triazine, the perfluoroether substituted-s-triazine [C₃F₇OCF(CF₃)CF₂OCF(CF₃]₃C₃N₃, 1,4-bis[(5-perfluoro-n-heptyl)-1, 2,4-oxadiazolyl]benzene, its perfluoroalky ether substituted analogue, and 3,5-bis(perfluoro-n-heptyl)-1,2,4-oxadiazole were synthesized and characterized. Each of these compounds was subjected to thermal and oxidative degradation at 235 and 325°C and to hydrolytic degradation at 235°C. Two benzene derivatives decomposed completely during heating in nitrogen or air at 325°C, tris(perfluoro-n-heptyl)-s-triazine was quantitatively hydrolyzed at 235°C. The perfluoroalkyl ether substituted triazine and 3,5-bis(perfluoro-n-heptyl)-1,2,4- oxadiazole were found to be stable under all conditions employed as evidenced by practically quantitative recovery of the test samples.     

Syntheses and degradations of fluorinated heterocyclics II. Perfluoroalkyl and perfluoroalkylether-1,2,4-oxadiazoles

3-Perfluoroalkylether-5-perfluoro-n-heptyl-1,2,4-oxadiazole and 3,5-bis(perfluoroalkylether)-1,2,4-oxadiazole were synthesized and characterized. The 3,5-bis(perfluoroalkylether)-1,2,4-oxadiazole was subjected to thermal, thermal oxidative, and hydrolytic degradations at 235 and 325°C and was found to be stable under these conditions as evidenced by practically quantitative recovery of the test samples. In the presence of Jet-A-fuel at 235°C a low degree of degradation,～4%, was observed. 3,5-Bis(perfluoro-n-heptyl)-1,2,4-oxadiazole was found to be stable to attack by water at 325°C; however in air in the presence of Jet-A at 235°C the extent of degradation was in excess of 10%.     

Synthesis and polymerization of 1-(2,4,6-tricyanophenylthio)-3-[3,5-bis(n,n-dimethylamino)phenoxy]-2-propyl methacrylate; polymer effect on intramolecular charge–transfer interaction

1-[3,5-Bis(N,N-dimethylamino)phenoxy]-ω-(2,4,6-tricyanophenylthio)alkanes ( 1a–c ), where an electron-accepting 2,4,6-tricyanophenylthio group and an electron-donating 3,5-bis(N,N-dimethylamino)phenoxy one are linked with a spacer such as ethylene, trimethylene, and tetramethylene, were prepared in order to examine an effect of the spacer chain length on intramolecular charge–transfer interaction between the 2,4,6-tricyanophenylthio and 3,5-bis(N,N-dimethylamino)phenoxy groups. From the UV-vis spectra measurements of 1a–c , 1-[3,5-bis(N,N-dimethylamino)phenoxy]-3-(2,4,6-tricyanophenylthio)Propane ( 1b ) carrying the trimethylene chain as a spacer was found to have the strongest intramolecular charge–transfer interaction. A new methacrylate-type monomer carrying the 1b unit as a side chain, 1-(2,4,6-tricyanophenylthio)-3-[3,5-bis(N,N-dimethylamino)phenoxy]-2-propyl methacrylate ( 2 ), was prepared successfully in 9.2% total yield in seven steps. The monomer 2 homopolymerized in benzene, tetrahydrofuran, acetone, and dimethyl sulfoxide in the presence of 2,2′-azobis(isobutyronitrile) at 60°C to give polymers [poly( 2 )] with molecular weights of 6,000 to 98,000. An intramolecular charge–transfer interaction in the poly( 2 ) was found to be larger than that in the monomer 2 and to increase with an increase in the degree of polymerization of the poly( 2 ), suggesting that there is an existence of polymer effect other than the polymer effect due to the high local concentration of the donor-acceptor pair. © 1995 John Wiley & Sons, Inc.     

Preparation of 2,4-bis(2,4,6-tri-tert-butylphenyl)-1,3-diphosphacyclobutenes from 2-(2,4,6-tri-tert-butylphenyl)-1-phosphaethyne and alkyllithiums

2-(2,4,6-Tri-tert-butylphenyl)-1-phosphaethyne was allowed to react with 0.5 eq. of alkyllithium to afford 2,4-bis(2,4,6-tri-tert-butylphenyl)-1,3-diphosphacyclobutenes through an intramolecular cyclisation of a 1,3-diphosphabuta-1,3-diene intermediate.     

Phospha-S-triazines. VI. Polymeric systems

Two types of polymeric phospha-s-triazines were synthesized: poly(perfluoroalkylethermonophospha-s-triazines) and monocyclic mono- and diphospha-s-triazines substituted on the carbon ring atoms by poly- (perfluoroalkylether) chains. The polymeric system consisting of the monophospha-s-triazine rings joined by perfluoroalkylether chains were found to have lower thermal oxidative stability than that shown by the corresponding dumbbell compounds. The monocyclic materials substituted by poly(perfluoroalkylether) chains possessed good thermal and oxidative stability, in addition to exhibiting anticorrosive and antioxidative properties.     

Flash vacuum pyrolysis of 1-methoxy-1,3-bis(trimethylsiloxy)-1,3-dienes: synthesis of α-allenic acids.

Flash vacuum pyrolysis at 680–700°C of 2- and 4- substituted 1-methoxy-1,3-bis (trimethylsiloxy)-1,3-butadienes yields α-allenic silyl esters which, upon hydrolysis, provide a direct route to α-allenic acids with good overall yield.     

Phospha-s-triazines II. Mass spectra of mono(diarylphospha)-s-triazines

Electron impact fragmentation patterns were obtained for 1-dephenylphospha-3,5-bis(perfluoro-n-heptyl)-2,4,6-triazine, 1-diphenylphospha-3,5-bis[C₃F₇(OCF(CF₃)CF₂)_xOCF(CF₃]-2,4,6-triazine (x=1 and 2) and their pentafluorophenyl analogues. In each instance the ion R₂PN₂C⁺ (RC₆H₅ or C₆F₅) constituted the base peak. Based on the observed metastable peaks, fragmentation pathways leading to the formation of this and other significant ions are postulated and similarities to s-triazine and diphenyl phosphazene trimer breakdown patterns are discussed.     

Theoretical calculation of nitro-1-(2,4,6-trinitrophenyl)-1H-azoles energetic compounds

In order to study the properties of new energetic compounds formed by introducing nitroazoles into 2,4,6-trinitrobezene, the density, heat of formation and detonation properties of 36 nitro-1-(2,4,6-trinitrobenzene)-1H-azoles energetic compounds are studied by density functional theory, and their stability and melting point are predicted. The results show that most of target compounds have good detonation properties and stability. And it is found that nitro-1-(2,4,6-Trinitrophenyl)-1H-pyrrole compounds and nitro-1-(2,4,6-trinitrop-enyl)-1H-Imidazole compounds have good thermal stability, and their weakest bond is C NO₂ bond, the bond dissociation energy of the weakest bond is 222–238 kJ mol⁻¹ and close to 2,4,6-trinitrotoluene (235 kJ mol⁻¹). The weakest bond of the other compounds may be the C NO₂ bond or the N N bond, and the strength of the N N bond is related to the nitro group on azole ring.     

Phospha-S-triazines. IX. Chloro-substituted monophospha-S-triazines and derivatives

1-Dichlorophospha-3,5-bis(perfluoro-n-heptyl)-2,4,6- triazine and one of its perfluoroalkylether analogues were synthesized by interaction of phosphorus pentachloride with the respective imidoylamidines; subsequent replacement of the chloro- by azido groups proceeded readily. 1-Chloro(phenyl)- phospha-3,5-bis(perfluoro-n-heptyl)-2,4,6-triazine was prepared by a parallel process using tetrachlorophenylphosphorane instead of phosphorus pentachloride; phenoxy and stearyloxy derivatives were formed without difficulty. All the compounds, with the exception of 1-stearyloxy(phenyl)phospha-3,5-bis(perfluoro- n-heptyl)-2,4,6-triazine, exhibited the characteristic mass spectral fragmentation patterns associated with the monophospha- s-triazine ring system.     

Synthesis of substituted 2-amino-4,6-bis(nonafluoro-tert-butyl)-1,3,5-triazines

A procedure was developed for the synthesis of substituted 2-amino-4,6-bis(nonafluoro-tert-butyl)-1,3,5-triazines from 2-chloro-4,6-bis(nonafluoro-tert-butyl)-1,3,5-triazine and aliphatic and aromatic amines. The data of¹⁹F NMR spectroscopy are indicative of the presence of a barrier to internal rotation. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1568–1572, August, 1999.     

Structural and coordination properties of 1,2-bis(cyclopropyl)-3,4-bis(2,4,6-tri-tert-butylphenyl)-3,4-diphosphinidenecyclobutene prepared by dehydrogenative homocoupling of 3-cyclopropyl-1-(2,4,6-tri-tert-butylphenyl)-1-phosphaallene

According to a protocol for the synthesis of phosphaallenes we recently established, 3-cyclopropyl-1-(2,4,6-tri-tert-butylphenyl)-1-phosphallene was obtained from (Z)-2-bromo-3-cyclopropyl-1-(2,4,6-tri-tert-butylphenyl)-1-phosphapropene. A novel bidentate ligand, 1,2-bis(cyclopropyl)-3,4-bis(2,4,6-tri-tert-butylphenyl)-3,4-diphosphinidenecyclobutene, was prepared by oxidative homocoupling of 3-cyclopropyl-1-(2,4,6-tri-tert-butylphenyl)-1-phosphaallene in the presence of butyllithium, together with the generation of hydrogen gas. The 1,2-bis(cyclopropyl)-3,4-diphosphinidenecyclobutene was allowed to react with (tht)AuCl (tht = tetrahydrothiophene) to afford the corresponding digold(I) complex of a six-membered metallacycle containing the P=C-C=P skeleton. The molecular structures of the 2-bromo-3-cyclopropyl-1-phosphapropene, 1,2-bis(cyclopropyl)-3,4-diphosphinidenecyclobutene and the digold complex were unambiguously determined by X-ray crystallography and are discussed from the point of view of the cyclopropyl conjugation.     

The thermal isomerization of cyclobutenes. XVI. 1,2-bis(trimethylsiloxy)cyclobutene

The gas phase thermal isomerization of 1,2-bis(trimethylsiloxy)cyclobutene has been studied in the temperature range 172°–204°C. The reaction is homogeneous, kinetically first order, and yields 2,3-bis(trimethylsiloxy)buta-1,3-diene as the only product. The rate constants fit the Arrhenius equation These results, taken with those obtained previously, demonstrate the insensitivity of the kinetics of the reaction to the nature of the groups substituted on the 1- and/or 2-positions of the cyclobutene ring.     

Trisubstituted 1,3,5-Triazines. 5. Reaction of 2,4,6-Tris[di(tert-butoxycarbonyl)nitromethyl]-1,3,5-triazine with Nucleophiles

The reaction of 2,4,6-tris[di(tert-butoxycarbonyl)nitromethyl]-1,3,5-triazine with ammonia, amines, and hydrazine has been studied. It was possible to substitute one of the di(tert-butoxycarbonyl)nitromethyl groups in this compound in the presence of ammonia, primary aliphatic amines, dimethylamine, and morpholine. The reaction with hydrazine leads to both mono- and disubstituted products. A double dealkoxylation occurs in the presence of diethylamine to give the bis(dimethylammonium) salt of 2,4-bis(tert-butoxycarbonylnitromethyl)-6-[di(tert-butoxycarbonyl)nitromethyl]-1,3,5-triazine.     

Synthesis, characterization, and dynamic DSC curing kinetics of novel epoxy resin of 2,4,6-tris(4-hydroxyphenyl)-1-3-5-triazine

2,4,6-Tris(4-hydroxyphenyl)-1,3,5-triazine was synthesized by cyclotrimerization of 4-cyanophenol using trifluromethanesulphonic acid as a catalyst at room temperature. 2,4,6-Tris(4-hydroxyphenyl)-1,3,5-triazine was epoxidized using alkali as a catalyst at 60 °C for 1 h. Epoxy resin was cured by DSC at multiple heating rates under nitrogen atmosphere by using 20 % of 4,4′-diamino diphenylsulphone, 4,4′-diaminodiphenylether, and 4,4′-diaminodiphenylcyclohexane as hardeners. Cured and uncured reins were also analyzed by TG analysis. Kinetic parameters were determined and discussed in light of nature of curing agents. Thermal decomposition behavior of the samples is also discussed in detail.     

Trisubstituted 1,3,5-triazines. 2. Synthesis of 1,3,5-triazines from 2,4,6-tris[di(tert-butoxycarbonyl)methylene]hexahydro-1,3,5-triazine

A study was carried out on electrophilic addition and hydrolytic dissociation of 2,4,6-tris[di(tert-butoxycarbonyl)methylene]hexahydro-1,3,5-triazine. Chloro, bromo, and methyl derivatives of tris[di(tert-butoxycarbonyl)methyl]-1,3,5-triazine were synthesized for the first time as well as 2,4,6-tris-(tert-butoxycarbonylmethyl)-1,3,5-triazine. For Communication 1, see ref. [1]. N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow and Institute of Chemical Physics, Russian Academy of Sciences at Chernogolovka, 142432 Chernogolovka, Moscow Oblast. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1404–1407, October, 1998.     

Nucleophilic Substitution Reactions of 2,4,6-Tris(trinitromethyl)-1,3,5-triazine. 3. Reaction of 2,4,6-Tris(trinitromethyl)-1,3,5-triazine with Azides and Hydrazine

As a result of nucleophilic substitution of the trinitromethyl groups in 2,4,6-tris(trinitromethyl)-1,3,5-triazine, the corresponding monoazido and diazido derivatives have been synthesized. The reaction of the starting triazine with hydrazine acetate in the presence of trifluoroacetic acid leads to 1-acetyl-2,2-bis[4,6-bis(trinitromethyl)-1,3,5-triazin-2-yl]hydrazine.     

Generation and conversion of the transient 1,1-bis(trimethylsilyl)-2-( 2,4,6-triisopropylphenyl)-silene

Treatment of 2,4,6-triisopropylbenzaldehyde with tris(trimethylsilyl)silylmagnesium bromide (2) gives 2,4,6-triisopropylphenyl-tris(trimethylsilyl)silyl-methanol (3) in approximately 70% yield and E-3,4-bis(2,4,6-triisopropylphenyl)-1,1,2,2-tetrakis(trimethylsilyl)-1,2-disilacyclobutane (5) (15%). 5 is the [2 + 2] head-to-head cyclodimer of the transient 1,1-bis(trimethylsilyl)-2-(2,4,6-triisopropylphenyl)silene (4), formed by trimethylsilanolate elimination according to a Peterson mechanism from the magnesium alkoxide, derived from the alcohol 3. Deprotonation of 3 with McLi at low temperature in ether produces a complex mixture of products, the main constituents being the silene dimer 5 (10%) and bis(trimethylsilyl)-2,4,6-triisopropylbenzyl-trimethylsiloxysilane (10) (60%), which is formed by readdition of the eliminated lithiumtrimethylsilanolate at the Si=C bond of 4. The deprotonation of 3 with McMgBr or PhMgBr (activated by LiBr) in THF at room temperature results in the formation of the polysilane (Me₃Si)₃SiSi(SiMe₃)₂CH₂(2,4,6-C₆H₂iPr₃) (13). Its generation indicates that there exists an equilibrium between the magnesium alkoxide derived from the alcohol 3 on one side, and the magnesium silanide 2 and 2,4,6-triisopropylbenzaldehyde on the other side. Possible pathways of the formation of the compounds mentioned, as well as of further by-products, are discussed. The 1,2-disilacyclobutane 5 is characterized by an X-ray crystal structure analysis.