The regiospecific N‐sulfonylation and N‐phosphorylation of benzoyl‐substituted heterocyclic ketene aminals

The regiospecific N‐sulfonylation and N‐phosphorylation of benzoyl‐substituted heterocyclic ketene aminals have been investigated. In the presence of sodium hydride, benzoyl‐substituted heterocyclic ketene aminals 1 or 2 reacted with p‐toluenesulfonyl chloride 3 to give (E)‐1‐(p‐toluenesulfonyl)‐2‐(aroylmethylene)imidazolidine 4 or (E)‐1‐(p‐toluenesulfonyl)‐2‐(aroylmethylene)hexahydropyrimidine 5, respectively. Under the same condition, 1 reacted with diethyl chlorothiophosphate 6 to give diethyl [2‐(aroylmethylene)imidazolidin‐1‐yl]thiophosphate 7. However, 2 failed to react with 6 to give N‐phosphorylated products. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 297–301, 1999     

The behavior of 2‐thioxo‐4‐thiazolidinones toward organophosphorus reagents

The reaction of 2‐thioxo‐4‐thiazolidinone ( 1a ) with phosphorus ylides 2a and 2b afforded compounds 5 and 6. On the other hand, formylmethylenetriphenylphosphorane (2c) reacts with 1a and its N‐methyl derivative 1b to give the new complicated phosphonium ylides 7a,b, respectively. Reactions of 1b with ylides 2a and 2d gave rise to the olefinic compound 8 and the new phosphorane product 9. Moreover, dialkyl phosphites 3a,b and trialkyl phosphites 4a–c react with 1a to give both the alkylated products 10a–c and the dimeric compounds 11,12. A mechanism is proposed to explain the formation of the new products.© 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 337–341, 1999     

Graft polymerization of epoxide and alternating graft copolymerization of epoxide–acid anhydride onto a polystyrene backbone having an aminimide moiety

Graft polymerization of glycidyl phenyl ether (GPE) and alternating graft copolymerization of GPE–succinic anhydride (SA) onto a polymer‐supported aminimide were examined. The polymer‐supported aminimide was synthesized by radical polymerization of 1,1‐dimethyl‐1‐(2‐hydroxy‐3‐(4‐vinylbenzyloxy)propyl)amine 2‐benzoylimide, which was prepared by the reaction of methyl benzoate with equimolar amounts of 1,1‐dimethyl hydrazine and 4‐glycidylmethylstyrene. This aminimide could initiate the polymerization of GPE and alternating copolymerization of GPE with SA to give the corresponding graft copolymers. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1041–1048, 1999     

Utilization of thiazolylacetonitriles in the synthesis of thiophene,thiazole, pyrazolo[1,5‐a]pyrimidine and pyrazolo [5,1‐c]triazine derivatives

Thiazolylcyanothioacetanilides react with α‐haloketones and haloesters to give the corresponding thiophene or thiazole derivatives according to the reaction conditions. Pyrazolo[1,5‐a]pyrimidines and pyrazolo[5,1‐c]triazines were synthesized by reaction of 3‐amino‐4‐(4′‐arylthiazol‐2′‐yl)‐5‐phenylaminopyrazole with different reagents. Structures of the new compounds were confirmed by elemental analyses, spectral data, and alternative methods of synthesis whenever possible. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 508–516, 1999     

Cycloaddition of CO2 and CS2 to a cyclic phosphazene

Carbon dioxide and carbon disulfide give crystalline cycloadducts with the phosphazene bond of a 1,2λ⁵‐azaphosphole. The CO₂‐adduct fully dissociates in solution, the CS₂‐adduct on short heating only to a small part. On longer heating, the latter rearranges in two successive 1,3‐shifts to give a thiophosphinylimino dihydrothiophene, the structure of which is revealed by X‐ray analysis. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10:167–170, 1999     

Heterocyclic synthesis via enaminones: Regioselective synthesis of some novel pyrazole,isoxazole, pyrimidine,pyrido[1,2‐a]benzimidazole and pyrazolo[1,5‐a]‐pyrimidine derivatives

2‐Acetylbenzothiazole ( 1 ) reacts with dimethylformamide dimethylacetal (DMF‐DMA) to afford the enaminone 2. Compound 2 reacts regioselectively with some nitrilimines 5a–d and nitrile oxides 6b–d to afford the novel pyrazole and isoxazole derivatives 11a–d and 12b–d, respectively, which react with hydrazine hydrate to give the new pyrazolo[3,4‐d]pyridazine and isoxazolo[3,4‐d]pyridazine derivatives 13a–d and 14b–d, respectively. The enaminone 2 reacts with 1H‐benzimidazole‐2‐acetonitrile ( 17 ) to afford the pyrido[1,2‐a]benzimidazole derivatives 19. Compound 2 reacts also with 5‐amino‐3‐phenylpyrazole ( 20 ) and with guanidine to afford the new pyrazolo[1,5‐a]pyrimidine and the 2‐aminopyrimidine derivatives 22 and 24, respectively. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 417–422, 1999     

Synthesis and characterization of 4,5‐dihydro‐1H‐pyrazolo[3,4b][1,4]azaphosphinines

1,3,3‐Trimethyl‐2‐(1‐R‐3‐methyl‐5‐pyrazolyliminoethylidene)indolines were shown to undergo phosphorylation with phosphorus(III) halides at the two nucleophilic carbon centers to give fused 1,4‐azaphosphinine ring systems. Chemical properties of the synthesized compounds were characterized. For some representative compounds, detailed NMR spectroscopic investigations were performed, including the determination of ³¹P, ¹H and ³¹P, ¹³C coupling constants. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 391–398, 1999     

Action of Lawesson's reagent on substituted 2‐amino‐1,4‐naphthoquinones: Novel synthesis of benzodiphenoquinone‐bis‐1,3,2‐thiazaphospholine‐2‐sulfide derivatives

1,3,2,4‐Dithiadiphosphetane‐2,4‐disulfide 1 reacts with substituted 2‐amino‐1,4‐naphthoquinons 2a–d to give 4,5,4′,5′‐benzodiphenoquinone‐bis‐1,3,2‐thiazaphospholine‐2‐sulfide derivatives of type 3. Compatible analytical and spectroscopic results were obtained for all the new compounds. A mechanism is proposed to explain the formation of compounds 3. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 488–491, 1999     

Samarium diiodide induced reductive cleavage of the Te–Si bond in phenyltellurotrimethylsilane: A novel method for the synthesis of alkylphenyl tellurides,telluroesters, and β‐phenyltelluro esters (nitriles)

Phentyltellurotrimethylsilane (1) was reduced by samarium diiodide in tetrahydrofuran (THF) to produce samarium phenyltellurolate. This new tellurolate anion reacted smoothly with alkyl and benzyl halides to give alkyl and benzyl‐phenyl tellurides in good yields under mild and neutral conditions. The samarium tellurolate also reacted with acyl halides or anhydrides to give telluroesters, and the 1,4‐addition of samarium tellurolate to α, β‐unsaturated esters (nitriles) gave β‐phenyltelluro esters (nitriles). © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 471–474, 1999     

The synthesis and reactivity of alkyl‐aminosubstitutedmethylenediphosphonates

Reactions of diethyl phosphite with Vilsmeier reagents, RCONR¹R²/POCl₃, afforded various alkylaminosubstitutedmethylenediphosphonates in acceptable yields, which (R = H) were then reacted with aldehydes under the conditions of the Wittig–Horner reaction to furnish vinylphosphonates, and which (R = H) underwent alkylation with alkyl halides to give alkylaminosubstitutedmethylenediposphonates 8 . (Z)‐Vinylphosphonates could be converted to (E)‐isomers in refluxing ethyl acetate.© 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 271–276, 1999     

Simple syntheses of benzothiazol‐2‐ylazoles

Syntheses of the title ring systems are described starting with benzothiazol‐2‐ylacetohydrazide (1). Thus, 1 was reacted with carbon disulfide to afford the 2‐methyl heteroaryl derivative 2, which on reaction with hydrazine hydrate yielded the corresponding triazole compound 3. Also, 1 can undergo a reaction with an isothiocyanate to give the N‐thiocarbonyl adduct 4 that can then be cyclized to produce a 2‐methyl heteroaryl analog 5 or 6. Compounds 8 or 9 could be obtained by the reaction of 1 with an aryl aldehyde followed by malononitrile or via its self‐cyclization, respectively. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 177–182, 1999     

A facile synthesis of potassium selenocarboxylates and their oxidation with XeF2 to diacyl diselenides: An X‐ray structural analysis of di(4‐methoxybenzoyl) diselenide

Several potassium selenocarboxylates were synthesized in moderate to good yields by the direct reaction of acyl chlorides with potassium selenide. The potassium salts were readily oxidized with XeF₂ to give diacyl diselenides in quantitative yields. The structure of di(4‐methoxybenzoyl) diselenide was established by X‐ray diffraction analysis. Intramolecular interactions between the carbonyl oxygen and the selenium that is connected to the opposite carbonyl group were observed. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 373–379, 1999     

Polymerization of (p‐vinylphenyl)hydrogalvinoxyl and formation of a stable polyradical derivative

4‐[(3,5‐Di‐tert‐butyl‐4‐hydroxyphenyl)(3,5‐di‐tert‐butyl‐4‐oxo‐cyclohexa‐ 2,5‐dienylidene)methyl]styrene (abbreviated as (p‐vinylphenyl)hydrogalvinoxyl) was polymerized using AIBN as an initiator to give a bright yellow polymer with M w = 3.2 × 10⁴. The polymer was oxidized to give the corresponding polyradical derivative, whose spin concentration could be increased up to about 70 mol % depending on oxidative conditions. ESR signal line‐width in the solid state was greatly increased below 200 K for the polyradical with a high spin concentration (> 50 mol %). The magnetization and magnetic susceptibility indicated weak antiferromagnetic interaction among the radical sites. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 189–198, 1999     

Soluble poly(amide–imide)s prepared by one‐pot solution condensation

A new one‐pot procedure for imide–acid monomer synthesis and polymerization is reported for four new poly(amide–imide)s. Bisphenol A dianhydride (BPADA) was reacted with twice the molar amount of 3‐aminobenzoic acid (3ABA) or 3‐amino‐4‐methylbenzoic acid (3A4MBA) in 1‐methyl‐2‐pyrrolidinone (NMP) and toluene mixture, and the amic acid intermediates cyclized in solution to give two diimide‐containing dicarboxylic acid monomers. Without isolation, the diacid monomers were then polymerized with either 1,3‐diaminomesitylene (DAM) or 1,5‐diaminonaphthalene (1,5NAPda) using triphenyl phosphite‐activation to give a series of four soluble poly(amide–imide)s, PAI. Isolation and purification of the dicarboxylic acid monomers was not necessary for formation of high molecular weight polymers as indicated by intrinsic viscosities of 0.64–1.04 dL/g determined in N,N‐dimethylacetamide (DMAc). All of the PAI were soluble in polar aprotic solvents such as NMP, DMAc, and dimethyl sulfoxide (DMSO). Glass transition temperatures ranged from 243 to 279°C by DSC, and 5% weight loss temperatures were above 400°C in both air and nitrogen. Flexible films cast from DMAc were light yellow, transparent, and tough. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1183–1188, 1999     

Aerobic epoxidation of olefins catalyzed by MgO–polysilazane–metal complexes

Co, Fe, Ni and Cu complexes of MgO‐supported polysilazane were prepared and found to be able to catalyze the aerobic epoxidation of long‐chain olefins to give corresponding epoxy‐alkanes in the presence of an aldehyde (as reductant) under mild conditions. When the Co complex catalyst was used for the aerobic oxidation of 1‐octene to give 1,2‐epoxy‐hexane, the yield and selectivity could achieve 92% and 100% respectively at 70 °C and under 1‐atm of O₂. The catalyst was very stable, and could be reused several times without any appreciable change in catalytic activity. Copyright © 1999 John Wiley & Sons, Ltd.     

Volume‐dependent potential approach for tungsten

A scheme to produce density‐of‐states‐(DOS)‐dependent potentials for d‐metals on the basis of the local density approximation calculations is suggested. As an example this scheme is applied to construct a DOS‐dependent potential for tungsten. The second moment of the tungsten DOS is calculated. We show that the obtained potentials give a good agreement of cohesive properties with the experimental data. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 71: 343–348, 1999     

Thermal cycloaddition reaction of symmetrical and unsymmetrical α‐diazo‐β‐diketones with 4‐aryl‐2‐methyl‐2,3‐dihydro‐1,5‐benzothia/diazepines

Symmetrical and unsymmetrical α‐diazo‐β‐diketones undergo thermal Wolff rearrangements to generate α‐carbonylketenes to participate as dienes in Diels–Alder reactions with 4‐aryl‐2‐methyl‐2,3‐dihydro‐1,5‐benzothia/diazepines to give, whereapplicable, regiospecific cycloadducts, 4a,5,6,12‐tetrahydro‐1H/1H,7H‐1,3‐oxazino[3,2‐d][1,5]benzo‐thia/diazepin‐1‐ones. A mechanism of formation of the regiospecific cycloadducts is suggested. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 35–40, 1999     

The improved synthesis,Diels‐Alder reactions,and desulfuration of trithio‐1,8‐naphthalic anhydride

In the presence of a strong Lewis base, such as Et₃N, trithio‐1,8‐naphthalic anhydride (3) is easily oxidized. Two improved syntheses of trithio‐1,8‐naphthalic anhydride (3) are described. Trithio‐1,8‐naphthalic anhydride (3) undergoes Diels‐Alder reactions with electron‐deficient alkenes to give novel fused heterocyclic compounds (6–11) that then can undergo a novel, gradual desulfuration dimerization with triethyl phosphite to afford 12 and its analogs 13 and 14. The structures of 6–14 are confirmed by microanalysis, IR, and NMR spectroscopy, and MS. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 141–146, 1999     

Theoretical study of reactions between AlH(1Σ) and HF molecule

Reaction mechanisms between AlH (¹Σ) and HF molecule are theoretically investigated. Ab initio calculations demonstrate that there are two parallel reaction channels: one is an addition reaction to give H₂AlF via the three‐membered ring transition state (TS) and the other is a dehydrogenation reaction to give AlF+H₂ via the four‐membered ring TS. The addition reaction is thermodynamically favorable and the dehydrogenation reaction is kinetically favorable. Thermodynamics and Eyring transition state theory (TST) with the Wigner correction are also used to compute the thermodynamic functions, the equilibrium constants, A factors, and the rate constants of these reaction channels at 200–1000 K. From the thermodynamics and TST calculations, it is valuable to point out that consideration on the entropy and thermal enthalpy is quite important in the study of chemical reactions on the basis of ab initio method. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 73: 417–424, 1999     

Reactions of cyclotrigermane and germylenes with carbonyl compounds: Cycloadducts and oligomers

Reactions of germylenes, generated by thermolysis of cyclotrigermanes, or of bulky germylenes, with various α‐dicarbonyl compounds are described. They proceed through a radical pathway, as confirmed by ESR measurements, to give different types of compounds. In the reaction of (Mes₂Ge)₃ with fluorenone, formation of the 2:1 ketone/germylene cycloadduct and of the oxadigermetane, resulting from a transient digermene, occurred. In the case of acenaphthene quinone, we observed the first example of cycloaddition between a digermene and an α‐diketone. The X‐ray crystal structure of the product shows a drastically distorted six‐membered ring system. The formation of oligomeric adducts was observed with parabenzoquinone. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 125–132, 1999