Low-frequency Raman spectra of odd α,ω-disubstituted n-alkanes

Low-Frequency Raman spectra of odd α,ω-dibromo- and α,ω-dihydroxy-n-alkanes were recorded. The longitudinal acoustic mode (LAM-1) frequencies were assigned by references to the published results for n-alkanes and even α,ω-disubstituted n-alkanes and also by taking account of the effects of end intermolecular forces and end-group masses by use of the chain model of Minoni and Zerbi.     

Study of the synthesis of poly(isobutylene-b-amide-11) by polycondensation of α,ω-dianhydride oligoisobutylene with α,ω-diamino oligoamide-11. I. Study of amine–anhydride and amide–anhydride reactions on low molecular weight models and on oligomers and polymers

The side reactions connected with the polycondensation of α,ω-diamino oligoamides and α,ω-dianhydride oligoisobutylenes are studied on low and high molecular weight models. Models for amine and anhydride end groups are dodecylamine and (2-dodecene-1-yl) succinic anhydride, respectively; their reaction is studied in the bulk (170°C) and in solution (142, 152, and 162°C); the products are analyzed by ¹H-, ¹³C-, and ¹H-¹³C-NMR and GPC. Some of these products and the junctions between the blocks are prepared independently. Models of amide groups in the chain are N-dodecyldodecanamide and N-dodecyloctadecanamide; their reaction with anhydride model results in cleavages with formation of imide groups. The results obtained from low molecular weight models are confirmed by studies on oligomers. They show unambiguous by that crosslinking which accompanies the block polycondensation originates from the reaction of amino-end groups with the intermediary acid groups resulting from the amine-anhydride reaction.     

Darstellung und Charakterisierung von α,ω-Dihydroperchloroligosilanen

Preparation and Characterization of α,ω-Dihydroperchloro Silanes Synthesis for the new compounds H(SiCl₂)_nH, n = 3?7 and HSi₄Cl₅ were described, starting from the perphenylated cyclosilanes. The new compounds were characterized and ¹H- and ²⁹Si-NMR spectra are discussed.     

Constitution moléculaire d'α,ω-difluoropolydiméthyl-N-méthylsilazanes. Equilibres obtenus par une réaction de redistribution

Unlike the α,ω-dihalogenopolydimethylsiloxanes, the α,ω-dichloropolydimethyl-N-methylsilazanes show a net preference for cyclic species with respect to linear structures at equilibrium. The aim of this study is to evaluate the perturbations in the molecular constitution of these α,ω-dihalogenopolydimethyl-N-methylsilazanes resulting from the substitution of the terminal chlorine atoms by fluorine atoms. This polymeric family was prepared by reacting (CH₃)₂SiF₂ with nonamethylsilazane [(CH₃)₂SiNCH₃]₃. The redistribution of the fluorine atoms with the bridging methylimino groups reached an equilibrium after about 5 months' heating at 150°C for all the samples prepared. The relative abundance of the various molecular species and fragments at equilibrium was deduced from the quantitative analysis of the proton nuclear magnetic resonance (NMR) spectra. The molecular constitution at equilibrium is described by two constants. The first, K = [neso] [middles in chains]/[terminal moieties]² = (2.8 ± 0.8) 10^?2, shows that the presence of terminal fluorine atoms is unfavorable to the formation of short chains. On the other hand, the trimeric cyclic species [(CH₃)₂SiNCH₃]₃ are found to be highly favored (K°₃ = 550 ± 100 mole/liter). These observations further confirm that the equilibrium constants which control the noncyclic part of polymeric families depend little on the functionality of the substituents exchanged [for example, on changing from ? N(CH₃)₂ to ? NCH₃? ] when the reorganization heat order is one.     

α,ω-Diisocyanatocarbodiimides, -Polycarbodiimides,and Their Derivatives

Research in the field of low-molecular weight, oligomeric and polymeric α,ω-diisocyanatocarbodiimides and -polycarbodiimides has been fruitful, not only in connection with these compounds themselves, but also—as so often happens in chemistry—with quite different problems. Novel synthetic methods, discoveries concerning the properties of low-molecular weight carbodiimides and phosphane imide derivatives, as well as results on the fragmentation reactions of four-membered heterocyclic compounds containing oxygen, phosphorus, and nitrogen, and a better understanding of the diisocyanate polyaddition process are among the many by-products of this research. The “high- and low-temperature formation” of polycarbodiimides and the homogeneous and heterogeneous catalysis of this process are described, and the fundamental importance of four-membered ring fragmentation mechanisms resulting in the formation of phosphane imide derivatives is outlined. Interesting building blocks for the diisocyanate polyaddition and polycondensation processes can be synthesized by many derivatization reactions of oligomeric and high-molecular weight polycarbodiimides and polyuretonimines. The in situ production of polycarbodiimides via matrix reactions in flexible polyurethane foams leads to a cellular arrangement of the material due to the pronounced symmetrical growth processes. Combination-foams with increased carbonation tendencies are formed in this way. Attention is drawn to several industrial applications of α,ω-diisocyanatopolycarbodiimides, of high-molecular weight cross-linked polyuretonimines, and of polycarbodiimide foams.     

Neuartige massenspektrometrische Zerfallsreaktionen bei α,ω-disubstituierten Alkanen. 15. Mitteilung über das massenspektrometrische verhalten von stickstoffverbindungen [1]

The mass spectral behaviour of α,ω-disubstituted alkanes and, especially, that of different N-substituted α,ω-diaminoalkanes has been investigated. It was found that the two amino groups which are separated by CH₂-groups can fragment only to a small extent indepently from each other. Yet those fragmentation reactions are predominant in which both functional groups participate. The main reactions of this type are:

• 1 Loss of the N-substituent (R) from the molecular ion, leading to the [M⁺—R]-ions.
• 2 Loss of NH₃, primary or secondary amines from the [M⁺—R]-ion in the case of monodi-, tri- and tetra-substituted diamino compounds respectively.
• 3 α-Cleavage to the non charged nitrogen atom by forming the ions
• 4 S_Ni-type fragmentation.

The mechanisms of these fragmentation patterns were deduced by using D-labelled derivatives, from metastabile peaks and high resolution mass spectrometry. These reactions seem to be typical for disubstituted alkanes.     

Block copolymer from α,ω-dihydroxyl polystyrene and polyethylene glycol

α,ω-Dihydroxyl polystyrene was synthesized by the addition of styrene oxide to polystyryl dianion initiated with sodium naphthalene. Diglyme was found to be an unsuitable solvent for the preparation of low molecular weight compounds. Block copolymerization of the α,ω-dihydroxyl polystyrenes (M?_n = 2250, 3140, and 6200) with poly(ethylene glycols) (M?_n = 404, 1960, and 5650) was pursued by introducing urethane linkages with 4,4′-diphenylmethane diisocyanate. The mechanical, thermal, and viscoelastic properties, solution viscosity, molecular weight distribution, and moisture absorption of the block copolymers obtained were examined. Incorporation of styrene blocks was found to disturb the crystallization and fusion of poly(ethylene glycol) blocks. Films cast from benzene solution were soft and elastic and absorbed up to 5.8% moisture.     

Ammoniakverlust aus α,ω-Alkandiaminen im Massenspektrometer. 22. Mitteilung über das massenspektrometrische Verhalten von Stickstoffverbindungen

Loss of ammonia from α,ω-alkanediamines in the mass spectrometer . Under electron impact α,ω-alkanediamines lose ammonia from the molecular ion. This fragmentation reaction is explained in the case of 1.4-butanediamine ( 1 ) on the basis of the spectra of homologues and deuteriated derivatives. The reaction proceeds via neighbouring group participation; the mechanism is given in Scheme 1.     

Preparation and thermal degradation of α,ω-alkylene bis[5-(1,2,3,4-thiatriazolyl)] sulfides

Syntheses of some extremely shock sensitive α,ω-alkylene bis[ 5-(1,2,3,4-thiatriazolyl)] sulfides via reaction of sodium 1,2,3,4-thiatriazoline thionate (1) and α,ω-dihaloalkanes are described. Dichloromaleic imide reacted analogously with 1 to give 3,4-bis(5-(1,2,3,4-thiatriazolyl)thio)maleic imide. The compounds decompose thermally in solution with formation of α,ω-alkylene bis(thio-cyanates), nitrogen and sulfur. The infrared spectra are discussed.     

Organische Phosphorverbindungen XXII. Darstellung und Eigenschaften von diprimären α,ω-Bis-phosphino-alkanen

The preparation and properties of diprimary α,ω-bis-phosphino-alkanes of the general structure H₂P(CH₂)_n PH₂ (n = 1, 2, 3, 4) are described. Their reactions with N-hydroxymethyl-dialkylamines and with olefins, which yield ditertiary α,ω-bisphosphino-alkanes, (R₂NCH₂)₂P(CH₂)_nP(CH₂NR₂)₂ and R₂P(CH₂)_nPR₂, respectively, are also reported. The physical properties of two new α,ω-bis-dialkylphosphinyl-alkanes have been determined.     

Retro-ene reactions IV. Alkylation of 4,5-dichloro-1-hydroxy-methylpyridazin-6-one with α,ω-dibromoalkanes or 4,5-dichloro-1 -(ω-bromoalkyl)pyridazin-6-ones

Alkylation of 4,5-dichloro-1-hydroxymethylpyridazin-6-one ( 1 ) with α,ω-dibromoalkanes 2 or ω-bromo-alkylpyridazin-6-ones 3 via a fragmentation of the retro-ene type under the two restricted conditions was investigated.     

α,ω-Dihydroxyalkan-α,α-diphosphonsäuren durch Desaminierung von ω-Aminoalkandiphosphonsäuren

α,ω-Dihydroxyalkane-α,α-diphosphonic Acids by Desamination of ω-Aminoalkanediphosphonic Acids The title compounds represent a new group of complexing diphosphonic acids which are synthesized by desamination of ω-amino-α-hydroxyalkane-α,α-diphosphonic acids. In case of α,ω-dihydroxypropane-α,α-diphosphonic acid ( 1 ) a phosphonylated phostone is formed by dehydration. In contrast, the ω-phenyl drivative of ( 1 ) yields in a smooth reaction under the same conditions 2-hydroxy-5-phenyl-3-phosphono-1.2-oxaphosphol-3-en-2-oxide ( 6 ).     

Synthèse et caractérisation d'une série de bis-9,9′(thio-9-acridinyl)-α,ω-alcanes

Some new bis-acridine derivatives have been prepared under phase transfer catalysis conditions. These are α,ω-bis-(9-thioacridinyl)alkanes with or without heteroatoms such as N or O, included into the bridge. In the latter case, general procedure has to be slightly modified due to a side-reaction leading to thiobenzyl derivatives, which increases in the conditions proposed in the first place. The compounds so prepared were characterized by their melting points, ¹H and ¹³C nmr data. Preliminary results referring to activity against P-388 lymphocitic leukemia are presented.     

α,ω-Bis(4-substituted-3-quinolinylthio)alkanes from reactions of thioquinanthrene with alkoxides

The reaction of thioquinanthrene 1 with sodium alkoxides and α,ω-dihaloalkanes leads to the formation of α,ω-bis[4-(4-methoxy-3-quinolinylthio)-3-quinolinylthio]alkanes 4 . The yield depends on the nature of α,ω-dihalo-alkanes. The effect of α,ω-dihaloalkanes of the following types: XCH₂X (X = Cl,Br,I), X(CH₂)₂X (X = Cl,Br,I), Br(CH₂)₃Br and Br(CH₂)₆Br were studied. The preparation of 4-alkoxy-3′-(ω-bromoalkylthio)-3,4′-diquinolinyl sulfide 3 and their transformation to α,ω-bis(4-alkoxy-3-quinolinylthio)alkanes 6 were studied as well.     

Beitrag zur Massenspektrometrie substituierter α, ω-Alkandiamine. 29. Mitteilung über massenspektrometrische Untersuchungen

Contribution to the mass spectrometry of substituted α,ω-alkane diamines The main mass spectral fragmentation pattern of compounds of types 1 to 4 is discussed. After loss of C₆H₅ · CH₂ · from the molecular ion the acid correspondin to the N,N-disubstituted residue is splitted off. The mechanism of this fragmentation reaction depends on the member of CH₂-groups between the two nitrogen atoms (Schemes 1 and 3) and on the substitution pattern of both nitrogens (Scheme 2).     

Chemistry of trifluorostyrenes and their dimers: 2. Synthesis of substituted α, β, β-trifluorostyrenes and α, β, β-trifluoroethenylnaphthalenes. Hammett correlations of their NMR parameters and the concept of “distorted π-electron clouds”

Six α, β, β-trifluorostyrenes with the following substituents, viz., p-MeO, p-Me, m-Me, p-Cl, m-Cl, and m-CF₃, were synthesized by the reaction of the corresponding Grignard reagents with tetrafluoroethylene in tetrahydrofuran. Similarly, α-and β-trifluoroethenylnaphthalenes were prepared. The substituent electronic effects on the ¹⁹F-NMR parameters were investigated for the trifluorostyrenes (I). Linear correlations between the Hammett σ constants and the following ¹⁹F-NMR parameters were established, namely, chemical shifts δ. (F¹) and δ (F²), coupling constants J₁₂, differences of chemical shifts Δδ_3-1 (δ (F³)—δ(f¹) or Δδ_3-2. The results are consistent with previous expectations based on the simple concept of “distorted π-electron clouds”. Facts are presented which indicate that the Δδ_3-1 (or Δδ_3-2) values may serve as empirical measures of the degree of polarization of the π bonds of these fluoroolefins.     

An efficient synthesis of telechelic poly (N‐isopropylacrylamides) and its application to the preparation of α,ω‐dicholesteryl and α,ω‐dipyrenyl polymers

Poly(N‐isopropylacrylamide)s (PNIPAMs) with cholesteryl or pyrenyl moieties at each chain end (CH‐PNIPAMs or Py‐PNIPAMs) were prepared via end‐group modification of α,ω‐dimercapto poly(N‐isopropylacrylamides), ranging in molecular weight from ～ 7000 to 45,000 g mol^?1 with a polydispersity index of 1.10 or lower. The telechelic thiol functionalized PNIPAMs were obtained by aminolysis of α,ω‐di(isobutylthiocarbonylthio)‐poly(N‐isopropylacrylamide)s (iBu‐PNIPAMs) obtained by reversible addition‐fragmentation chain transfer (RAFT) polymerization of N‐isopropylacrylamide in the presence of the difunctional chain transfer agent, diethylene glycol di(2‐(1‐isobutyl)sulfanylthiocarbonylsulfanyl‐2‐methyl propionate) (DEGDIM). The self‐assembly of the polymers in water was assessed by fluorescence spectroscopy, using the intrinsic emission of Py‐PNIPAM or the emission of pyrene added as a probe in aqueous solutions of CH‐PNIPAM. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 314–326, 2008     

α, ω-Alkan-bis-dimethylarsansulfide und -selenide,eine neue Klasse von Liganden

α ω-Alkane-bis-dimethylarsine Sulfides and Selenides, a Novel Class of Ligands The reaction of α,ω-alkane-bis-dimethylarsanes (CH₃)₂As? (CH₂)_n? As (CH₃)₂ with sulfur and selenium results in formation of the sulfides and selenides, respectively, (CH₃)₂As(X)? (CH₂)_n? As(CH₃)₂ or (CH₃)₂As(X)? (CH₂)_n? As(X)(CH₃)₂ (X = S, Se), which form chelat-complexes with the salts CoX₂ · 6 H₂O (X = Cl^?, Br^?, I^?, NO₃^?). The UV-spectra of the complexes are presented and discussed.     

Functional polymers and sequential copolymers by phase transfer catalysis. 18. Synthesis and characterization of α,ω-bis(2,6-dimethylphenol)–poly(2,6-dimethyl-1,4-phenylene oxide) and α,ω-bis(vinylbenzyl)–poly(2,6-dimethyl-1,4-phenylene oxide) oligomers

A novel and convenient synthetic method for the preparation of α,ω-bis(2,6-dimethylphenol)–poly(2,6-dimethyl-1,4-phenylene oxide) (PPO-2OH) is presented. It is based on the oxidative copolymerization of 2,6-dimethylphenol (DMP) with 2,2′-di(4-hydroxy-3,5-dimethylphenyl propane) (TMBPA) in a mixture of water–methanol or chlorobenzene–methanol. By using a 4/1 mole ratio of DMP to TMBPA and different solvent mixtures, it was possible to obtain bifunctional PPO-2OHs with number average molecular weights between 1000 and 5000. A phase-transfer-catalyzed etherification of PPO-2OH chain ends with a mixture of m- and p-chloromethylstyrene was used to synthesize α,ω-bis(vinylbenzyl)-poly(2,6-dimethyl-1,4-phenylene oxide)s (PPO-2VBs). The thermal polymerization of the PPO-2VBs was studied by differential scanning calorimetry, and has demonstrated a very high thermal reactivity for this new class of reactive oligomers.     

Nitro- and fluoropolyformals. II. Novel polyformals from α, ω-fluoro- and nitrodiols

The scope of polyformal formation from nitro- and fluorodiols has been explored further with a series of α, ω-diols. Polymers with M?_ns of 2000–4000 were generally obtained but M?_ns approaching 10,000 are possible in some cases. Effects of monomer structure and reaction parameters on polymer molecular weight are described. The polymers were characterized by GPC, ¹H-NMR, and DSC analysis.