Perfluorinated cyclo-tetrakis(phenylene sulfides): synthesis and structure

Perfluoro-cyclo-tetrakis(1,4-phenylene sulfide) has been synthesized by the reaction of tetrafluorobenzene-1,4-dithiol with perfluoro-1,4-bis(phenylthio)benzene. The reaction of tetrafluorobenzene-1,4-dithiol with perfluoro-m-xylene gives a macrocycle with 1,3- and 1,4-arrangement of bridged sulfur atoms.     

Self-assembled dynamics of silver nanoparticles and self-assembled dynamics of 1,4-benzenedithiol adsorbed on silver nanoparticles: Surface-enhanced Raman scattering study

Self-assembled dynamics of silver nanoparticles and self-assembled dynamics of 1,4-benzenedithiol (1,4-BDT) adsorbed on silver nanoparticles were investigated experimentally with surface-enhanced Raman scattering (SERS) and theoretically with density functional theory (DFT) and finite difference time domain (FDTD) method. The absorption spectroscopy of 1,4-BDT in silver sol at different time intervals was measured, which give the indirect evidence of self-assembled dynamics of silver nanoparticles and self-assembled dynamics of 1,4-benzenedithiol (1,4-BDT) adsorbed on silver nanoparticles. To obtain the direct evidence of self-assembled dynamics of silver nanoparticles and self-assembled dynamics of 1,4-benzenedithiol (1,4-BDT) adsorbed on silver nanoparticles, the SERS of 1,4-BDT were measured experimentally and investigated theoretically. The appearances of S–S stretching band (revealing the formation of multilayers of 1,4-BDT), and strongly enhanced S–C stretching, C–C ring stretching vibrational modes clearly show self-assembled dynamics of 1,4-BDT.     

Simons electrochemical fluorination of substituted homopiperazines(hexahydro-1,4-diazepines) and piperazines

Simons electrochemical fluorination (ECF) of 1,4-dimethyl-1,4-homopiperazine, methyl 4-ethylhomopiperazin-1-ylacetate and 1,4-bis(methoxycarbonylmethyl)-1,4-homopiperazine was studied. For comparison, ECF of three piperazines with a N-(methoxycarbonylmethyl) group(s) was also studied. ECF of 1,4-dimethyl-1,4-homopiperazine gave a low yield of corresponding perfluoro(1,4-dimethyl-1,4-homopiperazine) together with perfluoro(2,6-diaza-2,6-dimethylheptane) as the major product. Corresponding perfluoro(homopiperazines) with mono- and/or di-(fluorocarbonyldifluoromethyl) groups [CF₂C(O)F] at the 1- and/or 4-position were formed in low yields from methyl 4-ethylhomopiperazin-1-ylacetate and 1,4-bis(methoxycarbonylmethyl)-1,4-homopiperazine, respectively. These new seven-membered perfluoro(1,4-dialkyl-1,4-homopiperazines) were accompanied by the formation of mono- and/or di-basic linear perfluoroacid fluorides resulting from the CC bond scission at the 2- and 3-positions of the ring. From mono- and/or di-N-(methoxycarbonylmethyl)-substituted piperazines, corresponding perfluoropeperazines having the acid fluoride group(s) were formed in low yields.     

1,4-Dihydro-1λ5,4λ5-[1,4]diphosphinine und ein 1,4-Dihydro-1λ3,4λ3-[1,4]diphosphinin

1,4-Dihydro-1λ⁵,4λ⁵-[1,4]diphosphinines and a 1,4-Dihydro-1λ³,4λ³-[1,4]diphosphinine Reaction of thio- or dithiocarbonic acids with ethinyl amino phosphanes leads to 1,4-dihydro-1λ⁵,4λ⁵-[1,4]diphosphinine-1,4-disulfides. By this route compounds 4, 7 , and 8 have been prepared. Desulfurization of 4 with tri-n-butylphosphane results in 1,2,4,5-tetraphenyl-1,4-dihydro-1λ³,4λ³-[1,4]-diphosphinine 5 , which can be oxidized with tert-butyl-peroxide to the corresponding dioxide, 6 . From the reaction mixture of phenyl-phenylethinyl diethylamino phosphane and thioacetamide compound 4 and the unsymmetrical 1,4-dihydro-1λ⁵,4λ⁵-[1,4]diphosphinine 9 were isolated. Properties, nmr, ir and mass spectra of all new products are reported. A mechanism for the formation of 9 is suggested. The results of the X-ray structure determination of 8 and 9 are described.     

Hydrogen‐Assisted Unique Incorporation of 1,4‐Divinylbenzene in Copolymerization with Propylene Using an Isospecific Zirconocene Catalyst

Summary: Propylene was copolymerized with 1,4‐divinylbenzene (1,4‐DVB) using rac‐Me₂Si(2‐Me‐4‐Ph‐Ind)₂ZrCl₂ and MAO in the presence of hydrogen. ¹H NMR spectra of the obtained copolymer confirmed the successful incorporation of 1,4‐DVB. ¹³C NMR analysis revealed a unique copolymer structure with the incorporated 1,4‐DVB units predominantly forming 1,4‐substituted phenyl repeating units in the polymer main chain. A plausible mechanism involving spontaneous insertion of terminal styryl into Zr‐H species was proposed to rationalize the unique incorporation of 1,4‐DVB.

Copolymerization of propylene with 1,4‐divinylbenzene in the presence of hydrogen.     

Looking glass inhibitors: synthesis of a potent naringinase inhibitor l-DIM [1,4-dideoxy-1,4-imino-l-mannitol], the enantiomer of DIM [1,4-dideoxy-1,4-imino-d-mannitol] a potent α-d-mannosidase inhibitor

The synthesis of l-DIM [1,4-dideoxy-1,4-imino-l-mannitol] and of 1,4-imino-d-glycero-l-talo-heptitol from d-glycero-d-gulo-heptono-1,4-lactone depends on the use of pentan-3-one to form two five ring ketals as described by Burke, rather than the formation of one five ring and one six ring ketal formed with acetone. l-DIM, the enantiomer of the potent α-d-mannosidase inhibitor DIM [1,4-dideoxy-1,4-imino-d-mannitol] is a good inhibitor of naringinase (an α-l-rhamnosidase) with a K_i of 3.63 μM. 1,4-Imino-d-glycero-l-talo-heptitol is a moderate inhibitor of naringinase.     

Reactivity of N-arylsulfonyl-1,4-benzoquinone imines. Reaction with hydrazoic acid

N-Arylsulfonyl-2-halo-1,4-benzoquinone imines react with hydrazoic acid in boiling acetic acid via two pathways: the 1,4-addition and nucleophilic replacement of the halogen atom by an azido group, followed by the 1,4-addition of HN₃. In the reaction of N-arylsulfonyl-2,6-dihalo-1,4-benzoquinone imines with hydrazoic acid, both halogen atoms are replaced by azido groups, while N-p-tolylsulfonyl-2-methyl-1,4-benzoquinone imine takes up HN₃ molecule according to the 1,4-addition pattern.     

Reaction of N-arylsulfonyl-2(3)-arylsulfonylamino-substituted 1,4-benzoquinonimines with sodium arylsulfinates

N-Arylsulfonyl-3-arylsulfonylamino-substituted 1,4-benzoquinonimine reacts with sodium arylsulfinates regiospecifically along 1,4-addition scheme; N-tosyl-2-(tosylamino)-substituted 1,4-benzoquinonimine regioselectively affords products of 1,4- and 6,3-addition with the latter prevailing. Arylsulfinate anion enters predominantly in the para-position with respect to the ArSO₂NH group.     

Synthesis of Arylnaphthoquinones and Their Reactions with o‐Substituted Primary Aromatic Amines

Cycloaddition reaction of 2‐aryl‐1,4‐benzoquinones 1a‐d with a number of different dienes, namely 2,3‐dimethylbutadiene; 1,4‐diphenylbutadiene and anthracene yield 2‐aryl‐6,7‐dimethyl‐1,4‐ naphthoquinones 3a,b ; 2,5,8‐triphenyl‐1,4‐naphthoquinone 4 and 2‐aryl‐1,4,9,10‐tetrahydro‐9,10‐o‐benzoanthracene‐1,4‐dione 5 , respectively were investigated. In addition, the cycloaddition reaction of 2‐aryl‐1,4‐benzoquinones 1d,e with 2,3‐dimethylbutadiene was also investigated to yield 2‐aryl‐5,8‐dihydro‐6,7‐dimethyl‐1,4‐naphthohydroquinones 2a,b . Cyclocondensation reactions of Diels‐Alder adducts 2b, 3b, 5a with ethylenediamine, o‐substituted primary aromatic amines gave quinoxaline, phenazine, phenoxazine and phenothiazine ocyclic derivatives 6–14.     

Controlled stereochemistry of polyamides derived from cis/trans‐1,4‐cyclohexanedicarboxylic acid

A series of copolyamides 12.y was synthesized either with y = 6, or 1,4‐cyclohexanedicarboxylic acid (1,4‐CHDA) residue, or a mixture of both. The influence of the synthetic route of 1,4‐CHDA containing polyamides on the obtained cis–trans ratio of the incorporated 1,4‐CHDA was investigated. The use of acid chlorides provided a synthetic route with full control of the cis–trans ratio of the 1,4‐CHDA residue during synthesis, whereas synthesis at elevated pressure and temperature caused isomerization. The content and cis–trans ratio of 1,4‐CHDA in the copolyamides were determined by solution ¹³C NMR spectroscopy. Increasing the degree of partial substitution of the adipic acid by 1,4‐CHDA resulted in an increase in T_m, even for low molar precentages of 1,4‐CHDA. This phenomenon points to isomorphous crystallization of both the 12.6 and 12.CHDA repeating units. The mps of the synthesized polyamides were independent of the initial cis–trans ratio of 1,4‐CHDA, provided that the samples were annealed at 300 °C before DSC analysis. The polyamides exhibited a different melting pattern depending on the 1,4‐CHDA content. At a low a 1,4‐CHDA content a net exothermic recrystallization occurred during melting, whereas at higher contents of 1,4‐CHDA this recrystallization occurs to a lesser extent, and two separate melting areas are observed. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 833–840, 2001     

Preparation of 2,3- and 2,5-dihydropyrazine 1,4-dioxides from 2-hydroxyamino-2-methylpropanal oxime and some of their properties

3-Hydroxy-2,3-dihydropyrazine 1,4-dioxide derivatives were obtained by condensation of 2-hydroxyamino-2-methylpropanal oxime with glyoxal, diacetyl, and 1,2-cyclohexanedione in water, and 3-methoxy-2,3-dihydropyrazine 1,4-dioxide was obtained by condensation with diacetyl in methanol. 2,5-Dihydropyrazine 1,4-dioxide is formed when 2-hydroxyamino-2-methylpropanal oxime is heated in a solution of acetone and dilute hydrochloridic acid. The reduction of 3-hydroxy- and 3-methoxy-2,3-dihydropyrazine 1,4-dioxides and 2,5-dihydropyrazine 1,4-dioxide leads to 1,4-dihydroxypiperazines, and the bromination of 3-methoxy-2,3-dihydropyrazine 1,4-dioxide gives 5,6-bis(bromomethyl)-3-methoxy-2,3-dihydropyrazine 1,4-dioxide. 1,4-Dihydroxy-2,5-piperazinedione was obtained by oxidation of 2,5-dihydropyrazine 1,4-dioxide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1414–1418, October, 1983.     

Reaction of N-arylcarbamoyl-1,4-benzoquinone imines with sodium azide

N-Arylcarbamoyl-1,4-benzoquinone imines reacted with sodium azide in completely regioselective fashion according to the 1,4-addition pattern with formation of 1-(3-azido-4-hydroxyphenyl)-3-arylureas. The reaction of N-arylcarbamoyl-2,6-dichloro-3,5-dimethyl-1,4-benzoquinone imines with sodium azide afforded N-arylcarbamoyl-2,6-diazido-3,5-dimethyl-1,4-benzoquinone imines as a result of nucleophilic substitution of the chlorine atoms.     

Reactions of 5-oxo-1-phenylpyrrolidine-3-carbohydrazides with 1,4-naphthoquinone derivatives and the properties of the obtained products

N′-(4-Oxo-1,4-dihydronaphthalen-1-ylidene)-1-phenyl-5-oxopyrrolidine-3-carbohydrazides and N′-(3-methyl-4-oxo-1,4-dihydronaphthalen-1-ylidene)-1-phenyl-5-oxopyrrolidine-3-carbohydrazides were synthesized by reactions of 5-oxo-1-phenylpyrrolidine-3-carbohydrazides with 1,4-naphthoquinone or 2-methyl-1,4-naphthoquinone. The alkylated analogues of the above products were obtained using ethyl iodide. The interaction of 5-oxo-1-phenylpyrrolidine-3-carbohydrazides with 2,3-dichloro-1,4-naphthoquinone was followed by formation of N′-(3-chloro-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-1-phenyl-5-oxopyrrolidine-3-carbohydrazides. All these compounds were characterized using ¹H, ¹³C NMR, IR and mass spectra. Some of the new compounds were tested for the antimicrobial and antifungal activity.     

Preparation of dibenzofuran-type amorphous polyetherketone by novel etherification reaction

4-Fluorobenzophenone reacted with potassium carbonate in the presence of silica catalyst in diphenyl sulfone solvent to yield 4,4′-dibenzoyldiphenyl ether. This new etherification reaction was extended to three difluoro aromatic ketones. 4,4′-Bis(4-fluorobenzoyl)diphenyl ether ( I ) reacted with potassium carbonate to yield a crystalline poly(oxy-1,4-phenylene-carbonyl-1,4-phenylene) (PEK) and 4,4′-bis{4-[4-(4-fluorobenzoyl)phenoxy]benzoyl}benzene ( II ) gave a crystalline poly(oxy-1,4-phenylene-carbonyl-1,4-phenylene-oxy-1,4-phenylene-carbonyl-1,4-phenylene-oxy-1,4-phenylene-carbonyl-1,4-phenylene-carbonyl-1,4-phenylene)(PEKEKEKK). 2,8-Bis(4-fluorobenzoyl)dibenzofuran ( III ) or 2,8-bis(4-chlorobenzoyl)dibenzofuran ( IV ) reacted with potassium carbonate to yield a poly(oxy-1,4-phenylene-carbonyl-2,8-dibenzofuran-carbonyl-1,4-phenylene) (PEKBK). The PEKBK was a noval amorphous polymer with the glass transition temperature of 222°C and it showed excellent thermal stability [T. Tanabe and I. Fukawa, Jpn. Pat., Kokai 64–74223 (1989)]. Several amorphous dibenzofuran type polyetherketone copolymers were prepared by coplycondensation of III with 4,4′-difluorobenzophenone ( V ) or 1,4-bis(4-fluorobenzoyl)benzene ( VI ) [T. Tanabe and I. Fukawa, Jpn. Pat., Kokai 1153722 (1989)]. © 1992 John Wiley & Sons, Inc.     

Rearrangement of 1,4-benzodiazepin-2,4-diones to 3,l-benzoxazin-4-ones

Treatment of 7-chloro-3,4-dihydro-1H-1,4-benzodiazepin-2,5-dione (Ia) with refluxing acetic anhydride in the presence of pyridine afforded 6-chloro-2-methyl-4H-3,1-benzoxazin-4-one (IIa). A plausible reaction path for this novel rearrangement reaction is described: Ia → 4-acetyl-7-chloro-3,4-dihydro-lH-1,4-benzodiazepin-2,5-dione → 7-chloro-1,4-diacetyl-3,4-dihydro-lH-1,4-benzodiazepin-2,4-dione → IIa. When 7-chloro-3,4-dihydro-4-methyl-lH-1,4-benzodiazepin-2,5-dione (Ib), 3,4-dihydro-4-methyl-1H-1,4-benzodiazepin-2,5-dione (Id) and 3,4-dihydro-1-methyl-1H-1,4-benzodiazepin-2,5-dione (Ie) were allowed to react with acetic anhydride under conditions similar to those used for the rearrangement reaction, only acetylation occurred.     

Synthesis of condensed quinoxalines. Part II

A novel efficient synthesis of fluorescent, fused quinoxalines was achieved. 7-Triazolyl-1,4-dioxino[2,3-b]-quinoxalines were synthesized by the diazotisation of 7-amino-1,4-dioxino[2,3-b]quinoxaline and coupling with selected aromatic amines followed by air oxidation. Diazotised aryl amines were coupled with 7-amino-1,4-dioxino[2,3-b]quinoxalines followed by subsequent air oxidation afforded 1,4-dioxino[2,3-b]quinoxalino-[6,5-d]1,2,3-triazoles. 7-Amino-1,4-dioxino[2,3-b]quinoxaline was condensed with conjugated enol ethers followed by cyclization in dowtherm resulted in 1,4-dioxino[2,3-b]quinoxalino[6,5-b]pyridines.     

Synthesis and nuclear magnetic resonance analysis of starch‐g‐poly(1,4‐dioxan‐2‐one) copolymers

A new biodegradable starch graft copolymer, starch‐g‐poly(1,4‐dioxan‐2‐one), was synthesized through the ring‐opening graft polymerization of 1,4‐dioxan‐2‐one onto a starch backbone. The grafting reactions were conducted with various 1,4‐dioxan‐2‐one/starch feed ratios to obtain starch‐g‐poly(1,4‐dioxan‐2‐one) copolymers with various poly(1,4‐dioxan‐2‐one) graft structures. The microstructure of starch‐g‐poly(1,4‐dioxan‐2‐one) was characterized in detail with one‐ and two‐dimensional NMR spectroscopy. The effect of the feed composition on the resulting microstructure of starch‐g‐poly(1,4‐dioxan‐2‐one) was investigated. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3417–3422, 2004     

Chlorination of 2,3,6-trialkyl-5,8-dihydroxy-1,4-naphthoquinones with HCl-MnO<Subscript>2</Subscript> in acetic acid. effective transformation of 2,3,6-trialkyl-2,3,7-trichloro-1,2,3,4-tetrahydronaphthalene-1,4-diones into 7-chloro-2,3,6-trialkyl-5,8-dihydroxy-1,4-naphthoquinones

Chlorination of 2,3,6-trialkyl-5,8-dihydroxy-1,4-naphthoquinones with HCl-MnO₂ in acetic acid gave a mixture of 7-chloro-2,3,6-trialkyl-5,8-dihydroxy-1,4-naphthoquinones and 2,3,7-trichloro-2,3,6-trialkyl-1,2,3,4-tetrahydronaphthalene-1,4-diones, the latter being formed via addition of the second chlorine molecule to monochloro derivatives. The reduction of 2,3,7-trichloro-2,3,6-trialkyl-1,2,3,4-tetrahydronaphthalene-1,4-diones with sodium dithionite in alkaline medium resulted in the formation of 7-chloro-2,3,6-trialkyl-5,8-dihydroxy-1,4-naphthoquinones in high yield.     

Oxidation of 2-Chloro-1-phenylethane-1,1-dithiol

Oxidation of 2-chloro-1-phenylethane-1,1-dithiol with bromine, iodine, and elemental sulfur, as well as under UV irradiation, leads to formation of 1,4-bis(chloromethyl)-1,4-diphenyl-2,3,5,6-tetrathiane in 50–95% yield. Oxidation of the same substrate with selenium dioxide gives 1,5-bis(chloromethyl)-1,5-diphenyl-2,4-dithia-3-selenapentane-1,5-dithiol. On heating to 60°C, the latter loses selenium to afford 1,4-bis-(chloromethyl)-1,4-diphenyl-2,3-dithiabutane-1,4-dithiol.     

Palladium-catalyzed asymmetric tandem allylic substitution using chiral 2-(phosphinophenyl)pyridine ligand

Palladium-catalyzed asymmetric tandem allylic substitution of (Z)-1,4-diacyloxy- and (Z)-1,4-bis(alkoxycarbonyloxy)-2-butene (2a-c) using 2-(phosphinophenyl)pyridine 1 as chiral ligand provided optically active six-membered 2-vinyl-1,4-diheterocyclic compounds with good to high enantioselectivity. For example, the reactions with catechol, 2-(benzylamino)phenol, or 1,2-bis(benzylamino)ethane as a nucleophile gave 2-vinyl-1,4-benzodioxane (71% ee), 4-benzyl-2-vinyl-1,4-benzoxazine (86% ee), and 1,4-dibenzyl-2-vinylpiperazine (86% ee), respectively.