Polymerizations of substituted cyclopropanes. I. Radical polymerization of 1,1-disubstituted 2-vinylcyclopropanes

Diethyl 2-vinylcyclopropane-1,1-dicarboxylate (Ia), 2-vinylcyclopropane-1,1-dicarbonitrile (Ib), ethyl 1-cyano-2-vinylcyclopropanecarboxylate (Ic), and 1,1-diphenyl-2-vinylcyclopropane (Id) were radically homo- and copolymerized. Ia, Ib, and Ic polymerized cleanly in 1,5-type ring-opening fashion to yield polymers of high molecular weight. Id failed to homopolymerize but copolymerized with common monomers which included maleic anhydride. Infrared (IR) spectra indicated that the double bonds of the polymer chains were in trans form. All polymers were soluble in solvents and solution-cast films were clear and flexible, showing T_g values in the 25–40°C range. Model reactions of those monomers with benzenethiol also indicated predominant 1,5-addition reactions. From the results of our investigation it was concluded that the driving force for the facile radical 1,5-polymerization of Ia, Ib, and Ic was the stabilization of growing radicals by two substituents.     

Polymerizations of substituted cyclopropanes. II. Anionic polymerization of 1,1-disubstituted 2-vinylcyclopropanes

Among the four 1,1-disubstituted 2-vinylcyclopropanes, diethyl 2-vinylcyclopropane-1,1-dicarboxylate (Ia), 2-vinylcyclopropane-1,1-dicarbonitrile (Ib), ethyl 1-cyano-2-vinylcyclopropanecarboxylate (Ic), and 1,1-diphenyl-2-vinylcyclopropane (Id), Ib and Ic polymerized well with sodium cyanide in N,N-dimethylformamide. Ib was most reactive and a polymer (IIb) from Ib exhibited an inherent viscosity of 1.05 dl/g (concentration of 1.0 g in 100 ml of 95% H₂SO₄). All experimental results indicated that the polymerization proceeded by ring opening and that the structure of the polymers had pendant vinyl groups. The polymer IIc from Ic was soluble in common solvents like acetone, but IIb was soluble only in 95% H₂SO₄. Reactions of those compounds with benzenethiolate ion in ethanol yielded addition products that supported the ring-opening polymerization of those monomers. In the postulated mechanism of polymerization cyanide ion attacks the carbon of a cyclopropane ring with electron-releasing vinyl group and the resulting anion is thereby stabilized by two electron-withdrawing substituents. The propagation takes place by the reaction of the anion with another monomer molecule.     

Two novel polymorphic forms of iron‐chelating agent deferiprone

Thalassemia is a genetic blood disorder requiring life‐long blood transfusions. This process often results in iron overload and can be treated by an iron‐chelating agent, like deferiprone (3‐hydroxy‐1,2‐dimethylpyridin‐4‐one), C₇H₉NO₂, in an oral formulation. The first crystal structure of deferiprone, (Ia), was reported in 1988 [Nelson et al. (1988). Can. J. Chem. 66 , 123–131]. In the present study, two novel polymorphic forms, (Ib) and (Ic), of deferiprone were identified concomitantly with polymorph (Ia) during the crystallization experiments. Polymorph (Ia) was redetermined at low temperature for comparison of the structural features and lattice energy values with polymorphs (Ib) and (Ic). Polymorph (Ia) crystallized in the orthorhombic space group Pbca, whereas both polymorphs (Ib) and (Ic) crystallized in the monoclinic space group P2₁/c. The asymmetric units of (Ia) and (Ib) contain one deferiprone molecule, while polymorph (Ic) has three crystallographically independent molecules (A, B and C). All three polymorphs have similar hydrogen‐bonding features, such as an R₂²(10) dimer formed by O—H…O hydrogen bonds, an R₄³(20) tetramer formed by C—H…O hydrogen bonds and π–π interactions, but the polymorphs differ in their molecular arrangements in the solid state and are classified as packing polymorphs. O—H…O and C—H…O hydrogen bonds lead to the formation of two‐dimensional hydrogen‐bonded parallel sheets which are interlinked by π–π stacking interactions. In the three‐dimensional crystal packing, the deferiprone molecules were aggregated as corrugated sheets in polymorphs (Ia) and (Ic), whereas in polymorph (Ib), they were aggregated as a square‐grid network. The characteristic crystalline peaks of polymorphs (Ia), (Ib) and (Ic) were established through powder X‐ray diffraction analysis. The Rietveld analysis was also performed to estimate the contribution of the polymorphs to the bulk material.     

The ionization constants of 2‐substituted 4,6‐diamino‐s‐triazines: The applicability to the hammett and taft equations

The ionization (or basicity) constants (pK_b) were determined for many 2‐substituted 4,6‐diamino‐s‐tri‐azines ( I ) by means of the electrometric titration. I includes 2‐alkoxy or aryloxy‐( Ia ), 2‐alkyl‐ or 2‐aryl‐( Ib ), and 2‐alkylamino‐ or 2‐arylamino‐4,6‐diamino‐s‐triazines ( Ic ). For the series with the same alkyl or aryl group, the order of the basicity was found to be Ic < Ib < Ia . A study was made of relationships between the pK_b, values of I , and the substituent constants, σ_p, σ_m, σ_p⁺, σ_m⁺, σ_p^O, σ_m^o, σ_I, σⁿ, and σ*. The Hammett relationships were observed between the pK_a values of I, and the substituent constants σ_m, (or the combination ones, [0.97σ_m + 0.03σ_p] as well as another [0.77σ_I + 0.23σ_R]). The Taft relationships were also found between the pK_a values of Ia , Ib , and Ic and the constants σ_*, respectively. Furthermore, in the case of Ic a linear relationship was observed between the pK_a values and Σσ⁸.     

Polymerization of vinylcyclopropanes. II

1,5-Type polymerization of vinylcyclopropane proceeding by the opening of both the double bond and the cyclopropane ring was found. Some other vinylcyclopropane derivatives, 1,1-dichloro-2-vinylcyclopropane, 1,1-dibromo-2-vinylcyclopropane, isopropenylcyclopropane, 1-methyl-1-vinylcyclopropane, 1,1-dichloro-2-methyl-2-vinylcyclopropane, and cis- and trans-1-chloro-2-vinylcyclopropane, were investigated. The observation of infrared spectra, NMR spectra, and other data indicated that the radical polymerization of these compounds gave principally 1,5-type polymer, while in cationic polymerization 1,2-type was predominant. The behavior of the polymerization was discussed in terms of the stability of a cyclopropylcarbinyl ion or radical which is formed in the initiation and propagation steps.     

Polymerization of vinylcyclopropanes. IV. Radical copolymerization of 1,1-dichloro-2-vinylcyclopropane with maleic anhydride

Radical copolymerization between 1,1-dichloro-2-vinylcyclopropane (M₁) and maleic anhydride (M₂) was studied. Rearrangement of the radical caused from monomer M₁ and cyclization of growing chain, which was suggested from a consideration of composition and structure of the obtained copolymer, complicate the propagation step in this system. A peculiar copolymer composition equation containing four reactivity ratio parameters was developed, and these parameters were determined.     

Mass spectral studies of some aryl and aroyl derivatives of glyoxime

Mass spectra of two diaroylglyoximes (Ia and Ib) are reported and compared with those of the corresponding dehydration products, 3,4-diaroyl-1,2,5-oxadiazoles (IIIa and IIIb, respectively). In Ia and Ib, unlike in diarylglyoximes (Id and Ie), the largest ion is [M — 18]⁺, but this does not form in the ion source by a simple thermal dehydration. Similar spectra have been obtained for an alkyl aroyl derivative of glyoxime (Ic) and an isonitroso-β-diketone (II). A specific electron-impact-induced rearrangement leading to the formation of carboxylic acids has been observed in the mass spectra of all the acylated oximes under investigation.     

An Investigation by 31P-N.M.R. Spectroscopy into the Occurrence of High Energy Phosphates in Helminths (Worms)

Abstract

N-Phosphorylated guanidines (phosphagens,I), found in living tissue, act as high energy phosphate regulators of adenosine triphosphate. Vertebrates possess phosphocreatine (Ia) as their sole phosphagen whereas in invertebrates phosphoarginine (Ib) predominates. However, in certain non-parasitic helminths (Annelida), a novel class of phosphagens exists based on a phosphodiester structure (Ic) exemplified by phospholombricine (R′= CH₂ CH(NH₂)CO₂H).     

Study on the Interfacial Tensions Between Oils and Alkylbenzene Sulfonate Gemini Surfactant Solutions

Interfacial tensions (IFT) of five alkylbenzene sulfonate Gemini surfactants Ia, Ib, Ic, Id, and Ie at different oils/water systems were measured by a spinning drop interfacial tensiometer. And critical micelle concentration (CMC), the interfacial tension at CMC (γ_CMC), maximum interfacial excess concentration (Γ _max) and the surface area per molecule (A_min) were calculated. The results indicated that the CMC values determined with interfacial tension method were lower than those determined with surface tension method. And γ_CMC for Ie is larger than that for Ia, Ib, Ic, and Id. In addition, the effects of temperature and hydrophobic chains on dynamic IFT were also studied. With the increment of temperature, dynamic IFT is easier to reach a stable value. However, with the increment of hydrophobic chains, dynamic IFT is more difficult to reach a stable value. Each Gemini surfactant produces a minimum IFT when measured against a different n-alkane.     

Structure and Photochemical Properties of r‐1, c‐2, t‐3, t‐4‐l, 3‐Bis [2‐ (5‐R‐benzoxazolyl) ] −2,4‐di (4‐R' ‐phenyl) cyclobutane

r‐1, c‐2, t‐3, t‐4‐1,3‐Bis[2‐(5‐R‐benzoxazolyl)]‐2,4‐di(4‐R'‐phenyl)cyclobutane (IIa: R=R' = H; IIb: R=Me, R'= H; IIc: R = Me, R' = OMe) was synthesized with high stereo‐selectivity by the photodimerization of trans‐l‐[2‐(5‐R‐benzoxazolyl)]‐2‐(4‐R'‐phenyl) ethene (Ia: R=R' = H; Ib: R = Me, R' = H; Ic: R = Me, R' = OMe) in sulfuric acid. The structures of IIa–IIc were identified by elemental analysis, IR, UV, ¹H NMR, ¹³C NMR and MS. The molecular and crystal structure of IIc has been determined by X‐ray diffraction method. The crystal of IIc (C₃₄H₃₀N₂O₄. 0.5C₂OH) is monoclinic, space group P2₁/n with cell dimensions of a = 1.5416(3), b =0.5625(1), c = 1.7875(4) nm, β = 91.56 (3)°, V= 1.550(1) nm³, Z = 2. The structure shows that the molecule of IIc is centrosymmetric, which indicates that the dimerization process is a head‐to‐tail fashion. The selectivity of the photodimerization of Ia–Ic has been enhanced by using acidic solvent and the reaction speed would be decreased when electron donating group was introduced in the 4‐position of the phenyl group. That the photodimerization is not affected by the presence of oxygen as well as its high stereo‐selectivity demonstrated that the reaction proceeded through an excited singlet state. It was also found that under irradiation of short wavelength UV, these dimers underwent photolysis completely to reproduce its trans‐monomers, and then the new formed species changed into their cis‐isomers through trans‐cis isomerization.     

Ring-opening polymerization of 1-(p-substituted phenyl)-2-vinylcyclopropanes by Ziegler–Natta catalysts

1-(p-Substituted phenyl)-2-vinylcyclopropanes such as 1-phenyl-2-vinylcyclopropane (I_a), 1-(p-chlorophenyl)-2-vinylcyclopropane (I_b), 1-(p-anisyl)-2-vinylcyclopropane (I_c), and 1-(p-tolyl)-2-vinylcyclopropane (I_d) were prepared and polymerized radically, cationically and with Ziegler–Natta catalysts. I_a and I_b polymerized exclusively in 1,5-fashion with radical initiators. However, I_c and I_d polymerized in 1,5-fashion only with Ziegler–Natta catalysts. All polymers were soluble in ordinary organic solvent and solution-cast films were clear and flexible, showing T_g values in the range of 39–71°C. Spectral data indicated that the double bonds of the polymer chains were in trans form in all cases. The difference between the polymerizabilities of different monomers are interpreted in terms of electronic properties of substituents.     

Übergangsmetall-substituierte phosphane,arsane und stibane : XXV. C5H5(CO)2[P(OMe)3]M-substituierte dioxaphospholane und dioxarsolane; stereochemische evidenz für den intermolekularen ablauf einer isomerisierung unter methylgruppenverschiebung

2-C₅H₅(CO)₂[P(OMe)₃]Mo(W)-substituted 4,4,5,5-tetramethyl-1,3,2-dioxarsolanes and -dioxaphospholanes (Ia–Ic) are obtained from C₅H₅(CO)₃M derivatives via CO/P(OMe)₃ exchange. In all cases the phosphite ligand appears trans to the σ-bonded arsenic heterocycle, which prefers a conformation with the transition metal group in an axial position. The dioxaphospholane-metal (Ia) undergoes isomerization with alkyl migration at 0°C, which due to stereochemical reasons can only occur by an intermolecular mechanism.     

Die 2,6-Diisopropyl-phenylgruppe als sperriger Substituent in Bor-Stickstoff-Verbindungen. II [1]

The 2,6-Diisopropyl-phenyl Group as a Bulky Substituent in Boron-Nitrogen Compounds. II Fluoro-bis(amino)boranes R′ (Me₃Si)N–BF–NHR (R = 2,6-)Me₂CH)₂C₆H₃, R′ = Me ( Ia ), CH₂Me ( Ib ), CHMe₂ ( Ic ), CMe ( Id ), SiMe₃ ( Ie ), R ( If ) react with t-butyllithium (molar ratio 1:1) by elimination of HF to give the amino-imino-boranes ( IIa – f ). The thermal stabilities of the latter depend upon the steric requirement of the substituent R′, IIa – c and IIe dimerize to yield the diazaboretidines IIIa – c and IIIe. IId remains unchanged at 200°C and above, and IIf isomerizes forming the B–Me substituted diazasilaboretidine IVf . If a twofold amount of t-butyllithium is employed, B–CMe₃ substituted diazasilaboretidines ( Va – f ) are the main products. All compounds are characterized by elemental (C, H) analyses and their mass- and n.m.r. (¹H, ¹³C, ¹⁵N (in part), ¹⁹F, ²⁹Si) spectra. Characteristic i.r.-bands are reported for the amino-imino-boranes ( II ). An X-ray structure analysis is presented for IVf .     

The CuII−CuI−Cu0(Hg) system in the presence of benzotriazole: Part I. A polarographic investigation

A polarographic investigation of Cu^II electroreduction from solutions of benzotriazole (BTA) of pH from 1 to 3 at a dropping mercury electrode shows the presence of two successive adsorption waves of equal height (waves Ic and IIIc) due, respectively, to the formation and to the subsequent dissolution of an adsorbed film of a Cu^I compound. The dependence of the half-wave potential of wave IIIc, which is polarographically reversible, upon pH and BTA concentration indicates that the adsorbed film has the composition [Cu^I(BTA^?)], where BTA^? denotes the deprotonated anionic form of benzotriazole. Moreover, the maximum height of wave IIIc indicates that this film is one monolayer thick. A third cathodic wave (wave IIc), lying between waves Ic and IIIc, stems from the reduction to the metal state of the Cu^II ions diffusing from the bulk solution. Copper(0) oxidation at dropping amalgam electrodes in BTA solutions yields two successive adsorption waves (waves Ia and IIa). Wave Ia is due to the same electrode process, Cu⁰ (Hg)+BTA?Cu^I(BTA^?)+H⁺+e, responsible for the cathodic wave IIIc. On the other hand, wave IIa is due to the formation of roughly two adsorbed monolayers of [Cu^I(BTA^?)] upon that formed along wave Ia.     

Neue Gemischtligandenkomplexe mit Perthiocarboxylaten

New Mixed Ligand Complexes with Perthio Carboxylates Solutions of O-methyl-1,1-dithiooxalate (i-dtoMe) and metal(II)-chlorides (Ni^II, Pd^II) in the molar ratio 2:1 react with equimolar amounts of homonuclear bischelates of other 1,1- and 1,2-dithio-compounds L (L = i-mnt, Etxan, dto) to mixed ligand complexes M(ptoMe)L with spontaneous convertion of the 1,1-dithiooxalate into the corresponding perthio ligand (ptoMe) by sulfur insertion. Tetraphenylphosphonium-(1,1-dicyanoethene-2,2-dithiolato)(O-methyl-1,1 -perthio-oxalato)niccolat(II), Ph₄P[Ni(i-mnt)(ptoMe)], crystallizes in the monoclinic space group P2₁/n with a = 11.019(2) Å, b = 13.648(3) Å, c = 20.882(3) Å, β = 92.565(7)°. The formation of the perthio ligand is confirmed by ¹³C-NMR.     

Molecular designing,structural elucidation,and comparison of the cleavage ability of oxovanadium(IV) Schiff base complexes

Three novel oxovanadium(IV) Schiff base complexes [VO(Phen)(L)]SO₄, where L = 4[(benzylidene)amino]antipyrine (Ia), 4[(cinnamalidene)amino]antipyrine (Ib) and 4[(2-chlorobenzylidene)amino]antipyrine (Ic) are designed using benzaldehyde/cinnamaldehyde/2-chlorobenzaldehyde with 4-aminoantipyrine, 1,10-phenonthroline, and vanadyl sulfate in the 1: 1: 1 molar ratio. They are synthesized by the template method. The geometry of the complexes is elucidated by elemental analyses, IR, UV-Vis, ESR, CV, FAB mass, magnetic susceptibility, and conductance data. FAB mass spectrum shows the degradation of the complexes. The electronic spectra of the complexes reveal their square pyramidal geometry in which the ligands act as tetradentate. Their electrochemical parameters, the anodic and cathodic potentials, and the number of electrons transferred are calculated. One quasi-reversible peak and one electron-transfer redox processes corresponding to the formation of a VO(II)/VO(III) couple are observed. The antimicrobial activity of synthesized complexes are tested. The results are compared with the standard penicillin. DNA cleavage experiments showed that Ia exhibits higher cleavage efficiency, whereas Ib and Ic have the lower cleavage efficiency. The text was submitted by the authors in English.     

The thermal isomerization of 1,1-dimethyl-2-vinylcyclopropane to cis-2-methylhexa-1,4-diene via 1,5-hydrogen migration

The gas phase isomerization of 1,1-dimethyl-2-vinylcyclopropane to cis-2-methylhexa-1,4-diene has been studied in a static system. The isomerization is homogeneous and kinetically first order. The rate constants were independent of initial reactant pressure in the range 0.6 to 2 torr and of added nitrogen up to 180 torr. Rate constants determined at 10 temperatures in the range 200 to 254°C fitted the Arrhenius equation k = 10^11.41±0.02 exp (?33,540 ± 47 cal/RT) sec^?1 The low A factor and activation energy are consistent with a concerted 1,5-hydrogen migration via a “tight” cyclic transition complex.     

Different Complexation Behavior of P‐Functionalized Ferrocene Derivatives Towards SnCl2, SnCl4 and SnPh2Cl2: Auto‐ionization and Redox‐Type Reactions

The novel phosphonyl‐substituted ferrocene derivatives [Fe(η⁵‐Cp)(η⁵‐C₅H₃{P(O)(O‐iPr)₂}₂‐1,2)] ( Fc^1,2 ) and [Fe{η⁵‐C₅H₄P(O)(O‐iPr)₂}₂] ( Fc^1,1′ ) react with SnCl₂, SnCl₄, and SnPh₂Cl₂, giving the corresponding complexes [(Fc^1,2)₂SnCl][SnCl₃] ( 1 ), [{(Fc^1,1′)SnCl₂}_n] ( 2 ), [(Fc^1,1′)SnCl₄] ( 3 ), [{(Fc^1,1′)SnPh₂Cl₂}_n] ( 4 ), and [(Fc^1,2)SnCl₄] ( 5 ), respectively. The compounds are characterized by elemental analyses, ¹H, ¹³C, ³¹P, ¹¹⁹Sn NMR and IR spectroscopy, ³¹P and ¹¹⁹Sn CP‐MAS NMR spectroscopy, cyclovoltammetry, electrospray ionization mass spectrometry, and single‐crystal as well as powder X‐ray diffraction analyses. The experimental work is accompanied by DFT calculations, which help to shed light on the origin for the different reaction behavior of Fc^1,1′ and Fc^1,2 towards tin(II) chloride.     

Henry condensation under high pressure 2. Effect of aromatic aldehyde type and pressure on the yield of ω-nitrostyrenes and secondary processes

Condensation of aromatic aldehydes (I)-(XX) with EtNO₂ and n-PrNO₂ in AcOH in the presence of AcONH₄ or i-BuNH₂ gives primarily-nitrostyrenes (Ia, b)-(XXa, b) and small quantities of nitriles (Ic)-(XXc), oximes (Id)-(XXd), and ketones (Ie, f)-(XXe, f). The yields of (Ia, b)-(XXa, b) at P=1 atm are higher for acceptor substituents on the aromatic ring whereas at P=10 kbar, they are higher for donor substituents. High pressures suppress the formation of (Ic-f)-(XXc-f) and the Z-isomers of (Ia, b)-(XXa, b). The high pressure technique is especially useful in the preparation of donor-substituted (Ia, b)-(XXa, b) which are intermediates in the synthesis of the psychotropic -phenylethylamines.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 426–433, February, 1991.     

A New Route to Phosphoryl Thiocarbonyl Mixed Imides - Structure Limitations

Abstract

The rearrangement of N-methyl thiophosphoryl carbonyl mixed imides (I, XYP(S)N(Me)C(O)Z) to N-methyl phosphoryl thiocarbonyl mixed imides (II, XYP(O)N(Me)C(S)Z) was studied as a function of substitution on phosphorus (Ia: X = Y = MeO; Ib: X = Ph, Y = MeO; and Ic: X = Y = Ph) with Z = Ph and as a function of substitution on carbon (Ia: Z = Ph; Id: Z = Me; and Ie: Z = OiBu) with X = Y = MeO. For Ia, Ib, and Id, rearrangement is complete and quantitative. In contrast, Ic rearranges to a 10/90 equilibrium mixture of IIc/Ic and Ie gives no evidence for rearrangement to the phosphoryl thiocarbonyl mixed imide IIe. A relative reactivity order for Ia, Ib, Ic, and Id of 1.00, 0.15, 0.036, and 0.11 respectively, was observed in the rearrangements.