RADICAL IONS 561,2 ONE-ELECTRON OXIDATION OF 1,2-DITHIETE DERIVATIVES

Abstract

Novel 1,2-dithiete derivatives R₂C₂S₂ with R = [sbnd]C(CH₃)₃ and [sbnd]C(CH₃)₂[sbnd]CH₂[sbnd]CH₂[sbnd]CH₂[sbnd]C(CH₃)₂[sbnd] are readily oxidized by the one-electron transfer system AlCl₃/H₂CCl₂ to their radical cations. The single line ESR spectra, on high amplification, exhibit ³³S satellites in natural abundance. Both the ESR data, i.e. rather large g values and ³³S hyperfine coupling constants as well as MNDO closed and open shell calculations for the parent molecule H₂C₂S₂ illustrate that spin and positive charge are predominantly located in the SS bridge of the four-membered ring.     

METALLAPHOSPHENES AND DIPHOSPHENES

Abstract

Transient metallaphosphenes (rbnd2;M[dbnd]P[sbnd]) have been obtained by exchange reactions between disilylphosphines and organometaldihalides (M = Ge, Sn), or by thermolysis of 2-metallaphosphetanes (M = Si, Ge). They are characterized by trapping reactions with strained heterocycles. The first stable germaphosphene 12 has been synthesized by dehydrohalogenation from the parent halogermylphosphine and isolated in form of orange crystals. It is very reactive toward compounds with active hydrogen.

Transient diphosphenes ([sbnd]P[dbnd]P[sbnd]) have been prepared by the same type of exchange reactions between disilylphosphines and dichlorophosphines and characterized by trapping reactions on dienes. The second stable diphosphene 18 has been obtained by addition of t-BuLi on trisyldichlorophosphine. Its structure has been determined by X-ray diffraction and some aspects of its reactivity are described. The reaction of bisyltrichlorogermylphosphine with DBU affords the new stable and potentially reactive diphosphene 30.     

REACTIONS OF A PHOSPHORANIMINE ANION WITH SOME ORGANIC ELECTROPHILES

Abstract

The reactions of a variety of electrophiles with the N-silyl-P-trifluoroethoxyphosphoranimine anion Me₃Sin°P(Me)(OCH₂CF₃)CH^? ₂ (1a), prepared by the deprotonation of the dimethyl precursor Me₃SiN[dbnd]P(OCH₂CF₃)Me₂ (1) with n-BuLi in Et₂O at-78°C, were studied. Thus, treatment of 1a with alkyl halides, ethyl chloroformate, or bromine afforded the new N-silylphosphoranimine derivatives Me₃SiN[dbnd]P(Me)(OCH₂CF₃)CH₂R [2: R = Me, 3: R = CH₂Ph, 4: R = CH[sbnd]CH₂, 5: R = C(O)OEt, and 6: R = Br]. In another series, when 1a was allowed to react with various carbonyl compounds, 1,2-addition of the anion to the carbonyl group was observed. Quenching with Me₃SiCl gave the O-silylated products Me₃SiN[dbnd]P(Me)(OCH₂CF₃)CH₂°C(OSiMe₃)R¹R² [7: R ¹ = R ² = Me; 8: R ¹ = Me, R ² = Ph; 9: R¹ = Me, R ² = CH[sbnd]CH₂; and 10: R ¹ = H, R ² = Ph]. Compounds 2–10 were obtained as distillable, thermally stable liquids and were characterized by NMR spectroscopy (¹H, ¹³C, and ³¹P) and elemental analysis.     

STUDIES ON ORGANOPHOSPHORUS COMPOUNDS XXX. MASS SPECTROSCOPIC INVESTIGATION OF 2-ALKYL-2-OXO-1,3,2-DIOXA-PHOSPHORINANE AND-PHOSPHEPANE

Abstract

The mass spectra of 2-alkyl-2-oxo-1,3,2-dioxa-phosphorinane and-phosphepane showed that the ring opening was in competition with the cleavage of the P[sbnd]C bond. According to the fragmentation pathway, which was dependent on the structure of exocyclic substituents on phosphorus, the 2-alkyl-2-oxo-1,3,2-di-oxa-phosphorinanes can be classified in two categories. The main process in category A was the ring opening and/or C[sbnd]C bond cleavage. While in category B the cleavage of P[sbnd]C bond was predominant. However, for 2-alkyl-2-oxo-1,3,2-dioxa-phosphepane. no matter how the structure of 2-alkyl group was, the ring opening was a dominant process.     

Facile Preparation and Molecular Structure of a Novel Metacyclophane

Abstract

A novel 1,1,10,10,19,19-hexamethyl-5,14,23-trimethoxy[3.3.3]metacyclophane (2) was prepared in 25% yield by Friedel–Crafts cyclization of 4-(2-methoxyphenyl)-2-methylbutan-2-ol (1) at ? 78 °C using TiCl₄ as Lewis acid catalyst in anhydrous dichloromethane. The structure of cyclophane 2 was determined by single-crystal X-ray diffraction, and the impact of substrate concentration on the yield of macrocycle 2 was also examined. The study on the effect of substituents at the phenyl ring showed that the methoxy group in 1 is crucial for its trimerization to give the hexamethyl[3.3.3]metacyclophane derivative. Demethylation of 2 with BBr₃ gave 1,1,10,10,19,19-hexamethyl-5,14,23-trihydroxy[3.3.3]metacyclophane (4) in 96% yield, and its three hydroxyl groups provide the possible modification sites for further construction of supramolecular assemblies.     

OBERFLÄCHEN-REAKTIONEN 151,2 Heterogen Dechlorierungen von Phosphorchloriden (X)PCI3 und R[sbnd]PCI2 an [Ag], [Mg], [Cux/TiO2] und [MgCI2[sbnd]MgO/SiO2] sowie spektroskopische Evidenz für das Entstehen von Diphospha-dicyan P[tbnd]C[sbnd]C[tbnd]P aus CI2P[sbnd][tbnd][sbnd]PCI2

Abstract

Stimulated by the successful generation of unsaturated molecules with low-coordinated phosphorus centers by heterogeneous surface dechlorination, CI₂,P[sbnd]C[tbnd]C[sbnd]PCI², is synthesized and characterized by PE and mass spectra. In addition, [Mg] curls, [Ag] wool and catalysts [Cu_x/TiO₂] or [MgCI₂,[sbnd]MgO/SiO₂] are tested as potential dechlorinating agents for phosphorus halides like OPCI₃, SPCI₃, H₃C[sbnd]PCI₂, H₅C₂-PCI₂, (H₃C)₃C[sbnd]PCI₂, or H₅C₆-PCI₂, in a gasflow reactor under reduced pressure and yield, inter aha, the following representative results: due to the thermodynamically favored formation of [MgCl₂], [MgO] or [MgS] at the Mg surface, P₄ is the only gaseous product identified from reactions of OPCI₃, and SPCI₃, with [Mg] metal at higher temperatures. On the contrary, passing H₃C-PCI₂, at 600K over [Mg] yields a reaction mixture containing P(CH₃)₃,(H₃C)₂P[sbnd]P(CH₃)₂, (H₃C[sbnd]P), and CH₄, which suggests an intermediate formation of surface phosphinidenes [H₃C[sbnd]P →Mg]. Analogously, the pentamer (H₃C[sbnd]H₂C[sbnd]P)₅ can be isolated from ethyldichlorophosphane. Reaction of the evaporated diphospha-cyanogen precursor CI₂P[sbnd]C[tbnd]C[sbnd]PCI₂ with the catalyst [10% MgCI₂,/MgO/SiO₂], produces predominantly PCI₃, and P₄, but PE and mass spectra provide evidence that also minor amounts of the hitherto unknown molecule P[tbnd]C[sbnd]C[tbnd]P are formed.     

ELECTRON SPIN RESONANCE OR Pd(I). III: The Nature of the Metal-ligand Bonds in Square Planar Complexes of Palladium(I)

Abstract

ESR spectra for a variety of palladium(I) complexes produced in the powders and the frozen solutions of palladium(II) complexes by γ -ray irradiation have been interpreted in terms of the nature of the metal-ligand bonds. It has been found that the covalency for the palladium-ligand σ-bond increases in the order of Pd[sbnd]O, Pd[sbnd]Cl < Pd[sbnd]N < Pd[sbnd]S, Pd[sbnd]C, and that the nature of the metal-ligand bond in palladium(I) complexes is very similar to that in copper(II) complexes. The ratio of the magnitude of the ligand field splitting for palladium(I) complex to that for the copper(II) complex with the same ligand has been estimated from the comparison of their g values.     

THE PREPARATION AND CHARACTERIZATION OF Cd(XCN)4M TYPE COMPOUNDS

Abstract

A series of compounds of the type Cd(XCN)₄M (X=S and Se; M=Mn, Fe, Co and Zn) have been prepared and characterized. These compounds crystallize in the tetragonal system: space group I4[sbnd]S₄ ². The bidentate thiocynate and selenocyanate ligands coordinate to the “hard” M(II) ions through the nitrogen atom and the “soft” Cd(II) ion through the sulfur or selenium atom. The Cd[sbnd]Se bond in Cd(XCN)₄ M is slightly stronger than the Cd[sbnd]S bond while the M[sbnd]NCSe bond is slightly weaker than the M[sbnd]NCS bond. The M(II) ions tetrahedrally coordinated by the nitrogen end of XCN^? are in the high spin state. The [sbnd]NCS and [sbnd]NCSe ligands are located at about the same place in the spectrochemical series.     

CRYSTAL STRUCTURE OF THE NOVEL COMPOUND (1α, 3bT, 5α)-1,3-DIPHENYL-5-HYDRIDO-5-ISOPROPOXY-1λ6, 3λ6,2,4,6,5λ5-DITHIATRIAZAPHOSPHORINE-1,3-DIOXIDE. A COMPARISON WITH RELATED STRUCTURES

Abstract

The title compound (1α, 3β, 5α)-(NSOPh)₂NP(H)O-i-Pr crystallizes in the spacegroup P2₁/n with cell dimensions: a = 12. 150(2), b = 8.911(1), c = 17.614(3) Å, β = 107.52(1)^o; Z = 4. The structure was solved by direct methods and refined by least-squares techniques to an R value of 0.048 for 2420 independent reflections (collected at room temperature) with I > 2.5 σ(I). The unit cell contains dimeric units which are formed by unprecedented P[sbnd]H…O[dbnd]S bridges. The conformation of the inorganic ring skeleton can be described as a boat; phosphorus and sulfur atoms show a distorted tetrahedral geometry. The S[sbnd]N bond lengths differ slightly, ranging from 1.547(3) to 1.588(2) Å. The exocyclic bond lengths are P[sbnd]H = 1.34(2), P[sbnd]O = 1.553(2), S[sbnd]O = 1.439(2) (mean value), and S[sbnd]C = 1.767(4) (mean value) Å. From a comparison with analogous structures the degree of asymmetry (ΔI = {[P[sbnd]N]-[S[sbnd]N]}Å) in the SNP unit is related to the difference in electronegativity between the sulfur and phosphorus centres.     

Preparation and Properties of Novel Aromatic Polyamides from Diamines Containing 4,5-Imidazolediyl Structure

Novel aromatic polyamides were prepared from aromatic diamine containing 4,5-imidazolediyl unit, either by low temperature solution polycondensation or by direct polycondensation. Used diamines were 4,5-bis(4-aminophenyl)-2-phenylimidazole 1, 4,5-bis[4-(4-aminophenyl)]-2-(4-methylphenyl)imidazole 2 and 4,5-bis[4-(4-aminophenoxy)phenyl]-2-phenylimidazole 3. The obtained aromatic polyamides were produced with moderate to high inherent viscosity and soluble in polar aprotic solvents such as N,N-dimethylacetamide (DMAc), 1-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). Thermogravimetric analysis showed those polymers were stable up to 422°C in nitrogen atmosphere. The glass transition temperature (T _g)s of the polymers derived from diamine 3 were in the range between 243 and 275°C, and these values were approximately 120–160°C lower than those analogue polyamide I series containing no phenoxy units. The properties of polyamide I series are also compared with those of analogue polymers that order of aromatic nuclei and amide linkage is reversible.     

KINETICS AND MECHANISM FOR INTRAMOLECULAR ISOMERIZATION OF HRu3 (μ3-η3-EtSCCMeCMe)(CO)9 TO Ru3(μ-SEt) (μ3-η3-CCMeCHMe)(CO)9

Abstract

The kinetics for isomerization of HRu₃ (μ₃-η³-EtSCCMeCMe)(CO)₉ TO Ru₃(μ-SEt) (μ₃-η³-CCMeCHMe)(CO)₉, were determined. The overall process involves C[sbnd]H elimination, C[sbnd]S and Ru[sbnd]Ru bond cleavage and Ru₂(μ-S) bond formation. Activation parameters were determined from the temperature dependence (ΔH^? = 127(3) kJ/mol, ΔS^?= 56(11) J/mol-K) and from the pressure dependence (0[sbnd]207 MPa, ΔV^? ₀ +12.7(1.1) cm³/mol, Δβ^? = +0.037(0.012) cm³/(mol-MPa)) of the rate constant. The data are consistent with an intramolecular reaction involving significant metal-metal or carbon-sulfur bond cleavage in the transition state. The activation volume is too large to be accommodated by C[sbnd]H elimination alone and CO dissociation is not involved.     

SYNTHESIS OF 2,2-DISUBSTITUTED-1,3-PROPANE-DITHIOLS

Abstract

A method for the preparation of 2,2-disubstituted-1,3-propanedithiols from the corresponding diols is described. The success of the synthesis is governed by the solvent in which the nucleofilic substitution, dimesylate to dirhodanide, is performed. The proposed reaction sequence is tested out for several diols and the overall yields are very good with respect to the strongly hindered[sbnd]sterically ‐neopentyl-structure. All compounds are identified by ¹H-nmr.     

2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-5-(取代苯基亚甲基)-4- 噻唑啉酮的合成

以2-氨基-5-取代苯氧甲基-1,3,4-噻二唑(1)为起始原料, 合成了中间体2-氯乙酰氨基-5-取代苯氧甲基-1,3,4-噻二唑)-2-乙酰亚胺(2)和2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-4-噻唑啉酮(3), 化合物3进一步与取代苯甲醛发生类Knoevenagle缩合反应, 得到了一系列2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-5-(取代苯基亚甲基)-4-噻唑啉酮类化合物4a～4p. 目标化合物4a～4p的结构经IR, ¹H NMR和元素分析确证.     

Reactions with pyrrolidine-2,4-diones,II: New approaches to the synthesis of substituted 5,6-dihydropyrrolo[3,4-d][1,2,3]triazol-4(2H,4H)ones

Summary Approaches leading to 5,6-dihydro-5,6-diphenyl-2-substituted-pyrrolo[3,4-d][1,2,3]-triazol-4(2H,4H)-ones (10) are described. The first approach consists of cyclodehydrating 3(or 4)-hydroxyimino-1,5-diphenyl-4(or 3)-(4-substituted phenylhydrazono)pyrrolidin-2-ones (4,7) with boiling acetic anhydride. The second approach involves cyclization of 3(or 4)-acetoxyimino-1,5-diphenyl-4(or 3)-(4-substituted phenylhydrazono)pyrrolidin-2-ones (8,9) with elimination of acetic acid upon treatment with sodium hydroxide.Part of the work has been presented at the 8^th International Congress of Heterocyclic Chemistry (August 1981), Graz, Austria     

A Facile One-Step Synthesis of New Types of 8-Thiazolyl and 8-Thiadiazinyl Coumarins

N-[4-(7-Methoxy-4-methyl-2-oxo-2H-chromen-8-yl)-thiazol-2-yl]-guanidine ( 2 ) has been prepared by the condensation of 4-methyl-7-methoxy-8-(2-bromoacetyl)coumarin ( 1 ) with guanylthiourea. 4-Methyl-7-methoxy-8-[2-(N′-(1-phenyl-ethylideneisopropylidene)-hydrazino]-thiazol-4-yl]chromen-2-ones ( 3 , 4 , and 5 ) have been prepared by reaction of 4-methyl-7-methoxy-8-(2-bromoacetyl) coumarin ( 1 ) and thiosemicarbazide in presence of acetophenone or acetone without any solvent. The formation of these compounds was further confirmed by the condensation of acetophenone/acetone thiosemicarbazones with 4-methyl-7-methoxy-8-(2-bromoacetyl)coumarin ( 1 ) in anhydrous ethanol in a two-step process. Similarly 8-[2-[N′-(benzylidene)hydrazine]-thiazol-4-yl]-7-methoxy-4-methyl-chromen-2-ones ( 6 , 7 , and 8 ) have been prepared by the condensation of 4-methyl-7-methoxy-8-(2-bromoacetyl)chromen-2-one with thiosemicarbazide and various aromatic aldehydes in a single step without any solvent. The formation of these compounds was further confirmed by the condensation of appropriately substituted benzaldehyde thiosemicarbazones with 4-methyl-7-methoxy-8-(2-bromoacetyl)coumarin in anhydrous ethanol. 4-Methyl-7-methoxy-8-(2-bromoacetyl) chromen-2-one (1) upon condensation with 3,5-dimercapto-4-amino-s-triazole in anhydrous ethanol resulted in the formation of 8-(3-mercapto-3H-[1,2,4]triazolo[3,4-b]thiadiazin-6-yl)-7-methoxy-4-methyl chromen-2-one (9). This compound ( 9 ) on reaction with various alkyl and phenacyl halides in anhydrous ethanol gave corresponding 4-methyl-7-methoxy-8-[3-(2-oxo-substituted sulphanyl)-7H-[1,2,4]triazolo[3,4-b]thiadiazin-6-yl]chromen-2-ones ( 10 to 18 ). The structures of newly prepared compounds have been confirmed from analytical and spectral data.     

INTRODUCTION DE SYSTÈMES CAGE DANS LES MOLÉCULES D'INTÉRĚT BIOLOGIQUE. 2. ALKYLATION DES ESTERS SULFAMIQUES AU MOYEN D'UN DÉRIVÉ DE L'ADAMANTANE

Abstract

Sulfamic esters of the general type R[sbnd]O[sbnd]SO₂[sbnd]NH₂ were alkylated under solid-liquid, liquid-liquid phase transfer catalysis conditions and by noncatalytic procedure, in homogeneous medium, in the presence of an equimolar amount of triethylamine, by means of a 1-adamantyl bromomethyl ketone. According to the procedure and the nature of R, these reactions yield the N-monoalkyl, N-dialkyl derivatives or a cleavage of the O[sbnd]SO₂ bond with formation of the O-alkylation products.

Nous decrivons l'alkylation des esters sulfamiques de formule générale R[sbnd]O[sbnd]SO₂[sbnd]NH₂ au moyen de l'adamantyl-1 bromométhyl-cétone, en catalyse par transfert de phase solide-liquide, liquide-liquide et dans les conditions non-catalytiques, en phase homogène et en présence d'une quantité équimoléculaire de triéthylamine. Selon la méthode utilisée et la nature du radical R. on aboutit à des dérivés N-monoalkylés, N-dialkylés ou à la scission de la liaison O[sbnd]SO₂ avec formation de produits de O-alkylation.     

METAL ISOTOPE EFFECT ON METAL-LIGAND VIBRATIONS: V. CIS AND TRANS Ni(II) PHOSPHINE-HALIDE COMPLEXES

Abstract

Infrared spectra (4000–200 cm^?1) have been reported for Ni(DPE)X₂ where X is Cl, Br and I and DPE is 1,2-bis(diphenylphosphino)ethane. The Ni[sbnd]X and Ni[sbnd]P stretching bands have been assigned based on the observed isotopic shifts due to the ⁵⁸Ni-⁶²Ni substitution. The Ni[sbnd]X stretching frequencies are always lower and the Ni[sbnd]P stretching frequencies are always higher in the cis-complexes such as Ni(DPE)X₂ than in the corresponding trans-complexes such as Ni(PEt₃)₂X₂. These differences between cis and trans configurations have been attributed to the strong trans-effect of phosphine ligands.     

CARBODIPHOSPHAN (2.4.6-tBu3C6H2[sbnd]P[dbnd]2)C: REAKTION MIT ELEKTROPHILEN

Abstract

The reaction of Ar[sbnd]P[dbnd]C[dbnd]P[sbnd]Ar (Ar=2.4.6-^tBu₃C₆H₂) with electrophiles (H⁺, S₈) proceeds at the phosphorus atom with subsequent cyclisation of an o-^tbutyl group.     

Phthalazinone in Heterocyclic Synthesis: Synthesis of Some s-Triazole,s-Triazolothiadiazine,s-Triazolothiadiazine,and s-Triazolothiadiazole Derivatives as Pharmaceutical Interest

1(2H)-Oxophthalazine-2-acetic acid ethyl ester was allowed to react with various reagents under different conditions to yield compounds 2-[(4-substituted-5-mercaptotriazol-3-yl) methyl]-1 (2H)-oxophthalzines 5 and 7 which acted as starting materials for the preparation of some new s-triazolo[5,1-b][1,3]thiazine (8), s-triazolo[3,4-b][1,3,4]thiadiazine 9,12,14,20, and s-triazolo[3,4-b][1,3,4]thiadiazole 18,21 derivatives.

     

Über Reaktionen von Alkylbiguaniden mit Benzoin beimpH der Biguanidbasen

Summary Alkylbiguanides2 a–e react with benzoin (1) at thepH of the base in different ways.1 undergoes in presence of2 a, c oxidation to benzoic acid which reacts with the bases2 a, c to yield 4-phenyl-1,3,5-triazinamines3 c, 4 c; in presence of2 b 1 is transformed to benzil, which reacts with2 b under rearrangement to yield 1-(4-oxo-5,5-diphenyl-2-imidazolin-2-yl)-3,3-dimethylguanidine (5 b). However, the cycloalkylbiguanides2 d, e, react in presence of nitrogen as well as oxygen with1 to yield piperidine-1-[N-(4,5-diphenylimidazol-2-yl)-carboxamidine] (7 d), resp. morpholine-4-[N-(4,5-diphenylimidazol-2-yl)-carboxamidine] (7 e). The structure of7 e was established by means of an X-ray structure analysis. All proton- and carbon resonances were assigned on the basis of 2-dimensional NMR data.