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The synthetic utility of the methodology is demonstrated by the representative derivatization of one product [cf.

Polysubstituted piperidines were prepared via radical cyclization of α-aminoalkyl radicals onto unactivated double bonds. [1,2]-aza-Wittig rearrangements were observed when an aryl group was attached to the α-aminoalkyl radical center.

1,2,4-Triazole stabilized allene anions are intermediates for the synthesis of 4-alkyl-2(5H)-thiophenones and 8-phenylimino-1,2,4-triazolo[5,1-c]-1,4-thiazines. Structures are confirmed by X-ray crystallography.Key words: allene anion, 4-alkyl-2(5H)-thiophenones, 8-phenylimino-1,2,4-triazolo[5,1-c]-1,4-thiazines, X-ray crystallography.

1-(α-Alkoxyalkyl)benzotriazoles 1a−d add to phenyl vinyl ether to form key intermediates 4a−d, which readily undergo lithiation and subsequent trapping by a variety of electrophiles to give the expected substituted derivatives 7a−d, 9a−c, 11, 13, 15, and 18 in high yields. Subsequent hydrolysis of these compounds provides a novel high-yield acyl anion synthon approach for the synthesis of β-alkoxy ketones 8 or α‘-functionalized β-alkoxy ketones 10, 12, 14, 16, and 19 by short procedures from readily available starting materials.

Novel and facile routes to alkenyl, alkynyl, and aryl 1,2-diketones utilize treatment of benzotriazole derivatives 1, 7a,b, and 15a−d with butyllithium and subsequent reaction with esters or acid chlorides to yield the substituted intermediates 2a−d, 8a,b, and 16a−g. Reactions of the deprotonated 1 and 7 with α,β-unsaturated aldehydes followed by oxidation also produces similar intermediates 5 and 11a,b. Subsequent hydrolyses of the intermediates of type 2, 5, 8, 11, and 16 afford diverse 1,2-diketones in good yields.

1-(Benzotriazol-1-yl)-3-(diphenylphosphoryl)-1-ethoxy-1-propene (3), prepared from N-(α-ethoxyallyl)benzotriazole (1), underwent selective Horner reactions with aldehydes to give substituted dienes. Subsequent hydrolysis of these intermediates readily produced β,γ-unsaturated esters 2a−c in good yields. Similar reactions with ketones followed by hydrolysis of 10 produced, depending on the conditions, either the corresponding γ,γ-disubstituted β,γ-unsaturated esters 11a−d or γ-lactones 9a−c and 13. A double lithiation process provided β,γ,γ-trisubstituted β,γ-unsaturated esters 15, 18, and β,γ,γ-trisubstituted γ-lactone 14.

The dianion 12 (right harpoon over left harpoon 13) of 1-(1,2,4-triazol-1-yl)phenylpropargyl ethyl ether 11(readily prepared from phenylpropargylaldehyde diethyl acetal 8 and 1,2,4-triazole) reacts with alkyl halides, aldehydes, ketones, and alpha,beta-unsaturated ketones to give exclusively gamma-substituted allenic products of type 10. These adducts underwent mild in situ hydrolysis enabling convenient syntheses of alpha,beta-unsaturated esters 9a-c and alpha,beta-unsaturated gamma-lactones 16, 18, 20, and 22. Reactions of dianion 13 with imines generated the 1,3,4-trisubstituted 2-alkoxypyrroles 27, 30, and 31 in high yields. The alkyl-substituted analog 34 underwent similar reactions to give predominantly the gamma-products 39,40, and 42 along with a small proportion of alpha-analogs.

Rh(III)-catalyzed direct olefination of arenes with allyl acetate via C–H bond activation is described using N,N-disubstituted aminocarbonyl as the directing group. The catalyst undergoes a redox neutral process, and high to excellent yields of trans-products are obtained. This protocol exhibits a wide spectrum of functionality compatibility because of the simple reaction conditions employed and provides a highly effective synthetic method in the realm of C–H olefination.

The thermodynamic second dissociation constant K2 for sulfuric acid has been determined by conductivity measurements of aqueous sulfuric acid solutions at various temperatures. The data are treated by using two different methods developed with two independent assumptions due to Noyes et al. and Shedlovsky. Both methods require the knowledge of relevant ionic conductivities, which may be calculated from the Onsager limiting law. The values for K2 obtained with these two methods show excellent agreement. The value of 0.0103 mol-L−1 at 25°C agrees with the ‘best’ literature value of 0.0102 mol-L−1 within the experimental uncertainty, as also does the enthalpy of dissociation which is derived from the derivative of the temperature coefficient of K2.

The thermal degradation of melamine phosphonite has been explored by XPS (or ESCA). This process is different from that of melamine. The melamine became a dimer at 400 °C, but triazine ring breakage occurred in melamine phosphonite in the range 250 to 300 °C evolving much ammonia. As a result, the carbonic ester bond was broken and the valence state of P was P 5+ (P 2 O 5 ) due oxidation. Before thermal degradation the chemical state of the phosphorus in melamine phosphonite is different from that after thermal degradation. It should be emphasized that XPS can be used for the structure analysis of sparingly soluble or insoluble samples.

For making the surface hydrophobic, poly(ethylene terephthalate) (PET) films were subjected to treatment by CF4 and CF4/CH4 plasmas, and the PET fabrics, to impregnation (padding) with Oleophobol S for comparison. The electronic structure of the modified surface was differenentiated by XPS (ESCA). The surface dynamics upon heating and dipping into water was investigated by the angle-dependent XPS technique. Application of the XPS technique to these topics gave a wealth of information. © 1993 John Wiley & Sons, Inc.

Novel and facile routes to alkenyl, alkynyl, and aryl 1,2-diketones utilize treatment of benzotriazole derivatives 1, 7a,b, and 15a−d with butyllithium and subsequent reaction with esters or acid chlorides to yield the substituted intermediates 2a−d, 8a,b, and 16a−g. Reactions of the deprotonated 1 and 7 with α,β-unsaturated aldehydes followed by oxidation also produces similar intermediates 5 and 11a,b. Subsequent hydrolyses of the intermediates of type 2, 5, 8, 11, and 16 afford diverse 1,2-diketones in good yields.

1-(α-Alkoxyalkyl)benzotriazoles 1a−d add to phenyl vinyl ether to form key intermediates 4a−d, which readily undergo lithiation and subsequent trapping by a variety of electrophiles to give the expected substituted derivatives 7a−d, 9a−c, 11, 13, 15, and 18 in high yields. Subsequent hydrolysis of these compounds provides a novel high-yield acyl anion synthon approach for the synthesis of β-alkoxy ketones 8 or α‘-functionalized β-alkoxy ketones 10, 12, 14, 16, and 19 by short procedures from readily available starting materials.

1,2,4-Triazole stabilized allene anions are intermediates for the synthesis of 4-alkyl-2(5H)-thiophenones and 8-phenylimino-1,2,4-triazolo[5,1-c]-1,4-thiazines. Structures are confirmed by X-ray cr...

Ionic interaction in the three systems Hcl-HEPES (N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid), HCl-MOPSO (3-(N-Morpholino)-2-hydroxypropanesulfonic acid), and HCl-glycine have been studied in terms of their mutual influence on the respective activity coefficients of each component. Activity coefficients for each component of the three systems are calculated from emf measurements of solutions containing HCl and the amino acid in a H2/solution/AgCl,Ag cell at 25°C. The first dissociation constant of HEPES at 25°C has also been determined using emf and pH titration measurements.

1,2,4-Triazoles were synthesized on a solid support in three steps, with excellent yields and purities. The utility of this triazole-functionalized solid support was demonstrated by the solid-phase synthesis of various trisubstituted 1,2,4-triazoles.

A series of 3,4- and 3,5-disubstituted phenyl-containing cyclobutenedione analogues were synthesized and evaluated as CXCR2 receptor antagonists. Variations in the disubstitution pattern of the phenyl ring afforded new compounds with potent CXCR2 binding affinity in the low nanomolar ranges. Moreover, two potent compounds 19 and 26 exhibited good oral pharmacokinetic profiles.

Polysubstituted piperidines were prepared via radical cyclization of α-aminoalkyl radicals onto unactivated double bonds. [1,2]-aza-Wittig rearrangements were observed when an aryl group was attached to the α-aminoalkyl radical center.

Deprotonated 1-(benzotriazol-1-yl)-1-ethoxy-2-hexene (7) reacted with alkyl halides, aldehydes, ketones, imines, and alpha,beta-unsaturated esters to give exclusively the alpha-alkylated products 8a-c, 10a,b, 12, 14, 16, and 18a,b, respectively. Without isolation, these products were hydrolyzed under mild conditions to generate the corresponding simple or functionalized alpha,beta-unsaturated ketones 9a-c, 11a,b, 13, 15, 17, and 19a,b. Similar reactions with the phenyl-substituted analog 3-(benzotriazol-1-yl)-3-ethoxy-1-phenyl-1-propene (21) also gave the analogous alpha-products, but they were accompanied by small amount of the gamma-products in most cases. By contrast, deprotonation of the corresponding triazole derivative 29 with butyllithium followed by reactions with alkyl halides, aldehydes, ketones, or imines yielded exclusively gamma-alkylated adducts 32, 34, 36, 38, 40, and 42. Intermediates 32, 34, 36, 38, 40, and 42 were readily converted into beta-substituted esters 33a-c, gamma-lactones 35a,b, 39, 41, and 43, and gamma-lactams 37a-c on hydrolysis.

La seconde constante de dissociation de l'acide du titre a ete determinee, et les proprietes thermodynamiques ont ete calculees