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Two quinoxaline derivatives, 1 and 2, were prepared via a bis-aza-Wittig reaction when the suitable aromatic diamine was treated with (MeO)3PBr2/Et3N followed by the addition of benzil. Also, two additional novel heterocyclic compounds, 4 and 6 were prepared via an intramolecular aza-Wittig reaction.

Two quinoxaline derivatives, 1 and 2, were prepared via a bis-aza-Wittig reaction when the suitable aromatic diamine was treated with (MeO)3PBr2/Et3N followed by the addition of benzil. Also, two additional novel heterocyclic compounds, 4 and 6 were prepared via an intramolecular aza-Wittig reaction.

Acid hydrolysis of triphenylphosphite (1) are effectively catalyzed by anionic micelles of sodium lauryl sulfate (NaLS), alkylhydrogensulfate (2), tetradecanesulfonic acid (3a) and p.decyloxybenzenesulfonic acid (3b). Cationic micelles of cetyltrimethylammonium chloride (CTACI) inhibit the reaction. Rate effects were analyzed quantitatively in terms of distribution of reactants between water and the micelles; and the effect of added HCl or salt can be explained quantitatively in these terms.

Cationic micelles of hexadecyltrimethylammonium ion HTAX (X=Cl− and OH−) catalyzes the reactions of t-butyl phenyl carbonate with OH− and kΨ goes through maximum with increasing [HTACl] but it continues to increase with increasing [HTAOH]. Spontaneous hydrolysis of t-butyl phenyl carbonate is inhibited by both cationic and anionic micelles. The second-order rate constant in micelles is smaller than that in water.

A kinetic method for the accurate determination of cephalexin has been described. A solution of cephalexin is reacted with 5 × 10 −3 M cobalt(II) nitrate in 1 × 10 −3 M sodium hydroxide at 60°C for a fixed time of 6 min, after which the absorbance of the reaction product is measured at 310 nm. The concentration of cephalexin is calculated by using the corresponding calibration equation for the fixed-time method. The method has been applied to proprietary drugs and the results were compared statistically with those given by the BP method. The determination of cephalexin by the fixed-concentration and rate-constant methods is feasible with the calibration equations obtained but the fixed-time method has been found to be more applicable.

The reaction of N-alkyl-2-chloropyridinium ions (1a–f; alkyl = Me, n-hexyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl) with N3– is affected by cationic micelles of cetyltrimethylammonium ion (CTAX, X = Cl–, Br–, N3–), which inhibit the reaction of ion (1a) at low [surfactant] but catalyse it at high [surfactant]. First-order rate constants, kψ, for the reaction of ion (1b) continue to increase with increasing [surfactant] but, for reaction of the hydrophobic substrates (1c–f) at a given [NaN3], kψ goes through maxima with increasing [surfactant]. Reaction in CTABr is always faster than in CTACl, but the difference decreases with increasing substrate hydrophobicity so the rate–surfactant profiles do not fit the pseudophase, ion-exchange model. For reactions of substrates (1c–f) with N3–, kψ increases with [substrate] in the absence of surfactant and it also increases with [CTAN3]. The rate enhancement for reaction of ion (1f) in water is greater than that of ion (1a) by a factor of ca. 1.2 × 104, and this is probably due to self-micellization of 2-chloro-N-hexadecylpyridinium ion. Second-order rate constants for reactions of ions (1a–f) with N3– in MeCN–water (1:1 w/w) are very similar.

Added organic solvents (dimethyl sulfoxide is an exception) have opposite effects on the rates of formation and disappearance of the open-chain intermediate 4(R = NO2) involved in the hydrolysis of 2-chloro-3,5-dinitropyridine to the 2-pyridone by the nucleophilic ring-opening ring-closure mechanism. The ratio k1/k2 increases from 8 in water to over 1000 in 80% tetrahydrofuran at 25 °C and above. The effects are too complex to be analysed in terms of a single parameter, but an approach using the Kamlet–Taft solvatochromic parameters is applied successfully to six mixed aqueous solvent systems.

Cationic micelles of cetyltrimethylammonium surfactants [CTA(X), X = Cl, Br, OMs] increase first-order rate constants for the basic hydrolysis of tent-butyl perbenzoate and 2-naphthyl benzoate. Dealkylation of both butyl 4-nitrobenzenesulfonate and butyl 4-bromobenzenesulfonate by halide ions in micelles of CTACl, CTABr and CTAOMs, and by azide ion in micelles of cetyltrimethylammonium mesylate (CTAOMs) have been examined. The nucleophilic aromatic substitutions of 2-chloro-3,5-dinitropyridine by OH– and N3– ions in the presence of CTABr, CTACl and CTAOMs micelles have also been examined. The rate enhancements have been treated in terms of concentration of both substrates and nucleophilic anions at the micellar surface. The anionic concentrations depend upon specific and non-specific coulombic interactions, which were calculated by solving the Poisson–Boltzmann equation (PBE). The same parameters were used in fitting data for reactions of N3–, Br– or Cl– as nucleophiles and for systems with Cl–, Br– and OMs– as inert counter-anions in CTACl, CTABr and CTAOMs, respectively.

The reaction of N-alkyl-2-chloropyridinium ions (1a–f; alkyl = Me, n-hexyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl) with N3– is affected by cationic micelles of cetyltrimethylammonium ion (CTAX, X = Cl–, Br–, N3–), which inhibit the reaction of ion (1a) at low [surfactant] but catalyse it at high [surfactant]. First-order rate constants, kψ, for the reaction of ion (1b) continue to increase with increasing [surfactant] but, for reaction of the hydrophobic substrates (1c–f) at a given [NaN3], kψ goes through maxima with increasing [surfactant]. Reaction in CTABr is always faster than in CTACl, but the difference decreases with increasing substrate hydrophobicity so the rate–surfactant profiles do not fit the pseudophase, ion-exchange model. For reactions of substrates (1c–f) with N3–, kψ increases with [substrate] in the absence of surfactant and it also increases with [CTAN3]. The rate enhancement for reaction of ion (1f) in water is greater than that of ion (1a) by a factor of ca. 1.2 × 104, and this is probably due to self-micellization of 2-chloro-N-hexadecylpyridinium ion. Second-order rate constants for reactions of ions (1a–f) with N3– in MeCN–water (1:1 w/w) are very similar.

The reaction of Br− or Cl− with both n-butyl-4-nitrobenzenesulfonate and n-butyl-4-bromobenzenesulfonate 1a and 1b respectively is catalyzed by cationic micelles of cetyltrimethylammonium chloride or bromide (CTACl or CTABr respectively). The increase of rate constant with [surfactant] can be analyzed in terms of the concentration of substrate (1a - b) and halide ion in the micellar pseudophase, and the second-order rate constants in micellar and aqueous pseudophase are similar.

The reaction of hydroxide ion with methyl N-alkyl-N, N-dimethylglycinate(1) is catalysed by cationic micelles. The variation of the first-order constant, kψ , with the concentration of CTAC1 can be fitted to the pseudophase ion-exchange model, but this model fails when the counterion of the surfactant is OH-. The variations of kψ with counterion of CTAOH fit a kinetic model in which the distribution of the [OH-] between the aqueous and micellar pseudophase depends upon [OH-]. The value for the second-order rate constant in the micellar pseudophase predicted by both models is similar and it is smaller than the second-order rate constants in water.

The rates of spontaneous cis-trans isomerization of the complex cis-[PtCl2(PBu3)(PhCN)] have been measured in different solvents. Values of kobs decrease with the polarity of the solvent (benzene ∼ toluene $ CHCl3 ∼ DMF). 31P and 195Pt NMR spectroscopy provide (for the first time) strong evidence for dimer formation (sym. trans-[Pt2(μ- Cl)2(Cl)2(PBu3)2]) which are intermediates in spontaneous cis/trans isomerization.

The rates of spontaneous cis-trans isomerization of the complex cis-[PtCl2(PBu3)(PhCN)] have been measured in different solvents. Values of kobs decrease with the polarity of the solvent (benzene ∼ toluene $ CHCl3 ∼ DMF). 31P and 195Pt NMR spectroscopy provide (for the first time) strong evidence for dimer formation (sym. trans-[Pt2(μ- Cl)2(Cl)2(PBu3)2]) which are intermediates in spontaneous cis/trans isomerization.

The basic hydrolysis of t-butyl perbenzoate and 2-naphthyl benzoate has been studied in cationic micelles of cetyltrimethylammonium chloride or hydroxide (CTACl or CTAOH, respectively). The increase in rate constant with surfactant concentration can be analysed in terms of the concentration of (1), (2), and hydroxide ion in the micellar pseudophase; the determined second order rate constants in the micellar pseudophase are smaller than the second order constants in water.