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 ).     

Synthesis of 2-(ω-aminoalkyl)imidazolin-4-ones by ring chain transformation of lactam derivatives with α-aminoamides

Reaction of N-methylamides of biogenic (S)-α-amino acids 3 with lactam acetals 1 or lactim ethers 2 gives three types of products, i.e. N-methyl-α-lactamiminoamides 5 by condensation, 2-(ω-aminoalkyl)imidazolin-5-ones 7 or 2-(ω-lactamimmoalkyl)imidazolin-4-ones 8 by ring chain transformation. All products represent novel optically active derivatives of biogenic α-aminoacids.     

Beiträge zur Chemie der Si-N-Bindung XV [1]. α,ω-Dimethylchlorsilyl-substituierte Cyclodisilazane

α,ω-Dimethylchlorosily-substituted monomeric and oligomeric cyclodisilazanes were prepared by the reaction of dimethyl-dichlorosilane with hexamethylcyclotrisilazane in the molar ratios 1:1 to 1:3. The mechanism of these reactions was investigated.     

A Novel Route to α,ω‐Bis(acrylamidopeptide)‐Terminated Oligo(ethylene oxide) and Hydrogels

A new family of α,ω‐bis(acrylamidopeptide)‐terminated macromonomers were prepared via the ring‐opening addition of 4,4‐dimethyl‐2‐vinyl‐ and 2‐isopropenyl‐4,4‐dimethyl‐oxazol‐5‐on to α,ω‐diamine‐terminated poly(ethylene oxide). These macromonomers were used to produce hydrogels by means of thermally induced free‐radical polymerization. Swelling behavior and mechanical properties of the resulting hydrogels were influenced by the macromonomer type and the crosslinking density, as reflected by the equilibrium water uptake.     

Polyimides from 4,4′-(alkylene-α,ω-dioxy) bis(phenylsuccinic anhydride)s and bis(phenylglutaric anhydride)s

4,4′-(Alkylene-α,ω-dioxy)bis(phenylsuccinic anhydride)s and bis(glutaric anhydride)s were obtained by the condensation of 4,4′-diformyl-α,ω-diphenoxyalkanes with ethyl cyanoacetate followed by the addition of potassium cyanide or meldrum acid (2,2-dimenthyl-1,3-dioxane-4,6-dione), hydrolysis with concentrated hydrochloric acid, and dehydration with acetic anhydride. Alkylene groups were ethylene, trimethylene, and tetramethylene. Polyimides were prepared from these anhydrides with 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfide, and 4,4′-diaminodiphenylmethane through thermal ring closure of polyamic acids obtained by solution polymerization in dimethylacetamide, and thermal stability of these polyimide film was examined by thermogravimetric analysis.     

New telechelic polymers and sequential copolymers by polyfunctional initiator-transfer agents (inifers). XXX. Synthesis and quantitative terminal functionalization of α,ω-diarylpolyisobutylenes

Novel aromatic-telechelic polyisobutylenes were prepared and characterized: α,ω-diphenylpolyisobutylene, α-phenyl-ω-tolylpolyisobutylene, and α,ωditolylpolyisobutylene. The syntheses involved the preparation of asymmetric telechelic prepolymers (α-phenyl-ω-tert-chloropolyisobutylene and α-tolyl-ω-tert-chloropolyisobutylene) by the minifer method and quantitative alkylation of benzene and toluene by the prepolymer. The terminal aromatic rings of these telechelic polyisobutylenes were quantitatively nitrated, acetylated, and chlorosulfonated and a series of further novel telechelic products was obtained. Characterization of these derivatives provided additional proof for the telechelic structure of the starting prepolymers. The quantitative reduction of nitroaryl-telechelic polyisobutylene by SnCl₂/HCl led to aminoaryl-telechelic polyisobutylene which was used to cure bisphenol-A diglycidyl ether. These new flexible epoxy networks exhibited outstanding heat and hydrolytic stability combined with satisfactory mechanical properties.     

Salze von Halogenophosphorsäuren. XV. Sulfan-α,ω-diyl-bis(fluorodithiophosphate), Reaktionsprodukte des Fluoridabbaus schwefelreicher Phosphorsulfide

Salts of Halogenophosphoric Acids. XV. Sulfane-α,ω-diyl-bis(fluorodithiophosphates). Products of the Fluoride Degradation of Sulfur-rich Phosphorus Sulfides By the reaction of sulfur-rich phosphorus sulfides ?P₄S_10+m”? (m = 0,5 to 6) with fluorides MF (M = Na, K, NH₄) in acetonitrile or 1,2-dimethoxy-ethane mixtures of sulfane-α,ω-diyl-bis(fluorodithiophosphates) [(PFS₂)₂S_n]^2? (n = 1 to 8) are formed. The average chain length n of the sulfane derivatives depends on the S:P ratio of the starting phosphorus sulfides. The compounds are identified by ¹⁹F and ³¹P n.m.r. spectroscopy.     

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.     

Synthesis and characterization of α,ω-bis(4-hydroxybutyl) polydimethylsiloxanes

α,ω-Bis(4-hydroxybutyl) polydimethylsiloxane (molecular weight 1500 to 4500) can be pre-pared with well-controlled molecular weight through the reaction of 1,3-bis(4-hydroxybu-tyl)tetramethyl disiloxane and dimethoxydimethyl silane or diethoxydimethyl silane in the presence of a stoichiometric amount of water and hydrochloric acid. The molecular weight of these hydroxybutyl-terminated polysiloxanes can be determined fairly consistently by a titration method. These polysiloxanes are stable toward cyclization. © 1995 John Wiley & Sons, Inc.     

Reaction between ethyl ω-chloroalkylimidates and hydrazides

It is already known that ethyl ω-chloroalkylimidate hydrochlorides and aroyl hydrazides gave, when reacted together in boiling ethanol, 2-aryl-5-ω-haloalkyl-1,3,4-oxadiazoles. It has now been found that the reaction follows a different course in the presence of triethylamine. In particular, 2-aryl-5,6,7,8-tetrahydro-1,2,4-triazolo[5,1-α]pyridines were obtained from ethyl δ-chlorovalerimidate, whereas N-aroylaminoimino-pyrrolidines are the products obtained from ethyl γ-chlorobutyrimidate. A similar case, in which the closure of the triazole ring to obtain a dihydropyrrolotriazole was found to be more difficult than the corresponding closure to a tetrahydrotriazolopyridine, is described. Also the reaction between the imidates and carbethoxy-hydrazine, which gives piperidine and pyrrolidine derivatives, is reported.     

Synthesis of Macrocyclic Lactones via Ring Transformation of 4‐(ω‐Hydroxyalkyl)‐1,3‐oxazol‐5(4H)‐ones

The synthesis of α‐benzamido‐α‐benzyl lactones 23 of various ring size was achieved either via ‘direct amide cyclization’ by treatment of 2‐benzamido‐2‐benzyl‐ω‐hydroxy‐N,N‐dimethylalkanamides 21 in toluene at 90 – 110° with HCl gas or by ‘ring transformation’ of 4‐benzyl‐4‐(ω‐hydroxyalkyl)‐2‐phenyl‐1,3‐oxazol‐5(4H)‐ones under the same conditions. The precursors were obtained by C‐alkylations of 4‐benzyl‐2‐phenyl‐1,3‐oxazol‐5(4H)‐one ( 15 ) with THP‐ or TBDMS‐protected ω‐hydroxyalkyl iodides. Ring opening of the THP‐protected oxazolones by treatment with Me₂NH followed by deprotection of the OH group gave the diamides 21 , whereas deprotection of the TBDMS series of oxazolones 25 with TBAF followed by treatment with HCl gas led to the corresponding lactones 23 in a one‐pot reaction.     

The transacetalization reaction during the etherification of poly(oxymethylene)diol [α-hydro-ω-hydroxypoly(oxymethylene)] with orthoesters in the presence of lewis acids

A transacetalization reaction occurs during the etherification of poly(oxymethylene)diol [α-hydro-ω-hydroxypoly(oxymethylene)] with orthoesters and an important modification of molecular structure takes place. The intermediates formed during the transacetalization reaction are emphasized. The connection between this reaction and the other reactions during the etherification of poly(oxymethylene)diols is discussed.     

Synthesis of granatanine-3-spiro-5'-hydantoin-N-ω-hydroxyalkyl esters

Synthetic methods to prepare N-ω-hydroxyalkyl-nor-psuedopelletierine and granatanine-3-spiro-5'-hydantoin N-ω-hy droxyalkylbenzylic and diphenylacetic esters are analyzed. The Bucherer-Bergs synthesis used by us to obtain some other granatanine-spirohydantoins (2), originates the hydrolysis of the ester group.     

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.     

The reaction of 2-(ω-chloroalkyl)benzimidazoles with thiourea. Studies on heterocyclic compounds. I

By reaction of the appropriate 2-(ω-chloroalkyl)benzimidazoles with thiourea, 2-(α-mercaptoalkyl)benzimidazoles (IV) have been prepared. The attempted preparation of 2-(β- and γ-mercaptoalkyl)benzimidazoles failed. β-Elimination was observed by alkaline treatment of S-[2-(2-benzimidazolyl)-propyl]isothiuronium chloride (VII), whereas 2-(γ-chlorobutyl)benzimidazoles did not give an isothiuronium chloride.     

Photolyse stéréosélective des [α-tétrahydropyrannyloxy] -2 tétrahydropyrones-3

The photochemical irradiation of the 2-[sα-tetrahydropyrannyl-oxy]-3-tetrahydropyrones (3) gives the -3-tetrahydropyrone (6)and the α-valerolactone (7). the structures (S*, R*) or (S*, S*) which were determined by mmr and by comparison with the 2-[α-tetrahydropyrannyloxy]-2tetrahydropyrannes (5) (S*, R*) and (S*, S*) influence the rate of the photolysis     

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.     

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.     

Synthesis of 3-alkylquinoxalin-2(1<Emphasis Type="Italic">H</Emphasis>)-ones via Grignard reaction

A two-step procedure has been developed for the synthesis of 3-alkylquinoxalin-2(1H)-ones from o-phenylenediamine and ethyl 2-oxoalkanoates prepared by the Grignard reaction of diethyl oxalate with alkyl bromides. Analogous reaction with α,ω-dibromoalkanes instead of alkyl bromides leads to the formation of 3,3′-(alkane-α,ω-diyl)di[quinoxalin-2(1H)-ones].     

Photochemical behavior of 4-(ω-enyl)- and 4-(ω-dienyl)-2-pyrones

4-(ω-Enyl)-2-pyrone 3 and two types of 4-(ω-dienyl)-2-pyrones 4–6, 9 and 10 were prepared and the photochemical behavior was investigated. Photosensitized reaction of 3 afforded [2+2]-cycloadduct 11 site-specifically. On the other hand, 4 and 5 gave geometrical isomers, respectively. 2-Pyrones 6, 9 and 10 possessing pendant furans gave no adduct. The reasons for the differences are described.