The reactions of the title thionocarbonates (1 and 2, respectively) with a series of secondary alicyclic amines and pyridines are subjected to a kinetic investigation in 44 wt % ethanol-water, 25.0 degrees C, ionic strength 0.2 M (KCl). Under amine excess over the substrates pseudo-first-order rate coefficients (k(obsd)) are obtained for all the reactions. Those of the alicyclic amines with the two substrates show nonlinear upward plots of k(obsd) vs [amine], except the reactions of piperidine, which exhibit linear plots. For these reactions a reaction scheme is proposed with two tetrahedral intermediates, one zwitterionic (T(+/-)) and the other anionic (T(-)), with a kinetically significant proton transfer from T(+/-) to an amine to give T(-). From an equation derived from the scheme the rate microcoefficients are obtained through fitting. The rate coefficient for formation of T(+/-) (k(1)) is larger for 1 compared to 2, which can be explained by a stronger electron-withdrawal of 4-nitro in 1 than 3-nitro in 2, which leaves the thiocarbonyl carbon of 1 more positive and, therefore, more susceptible to nucleophilic attack. For the pyridinolyses of both thionocarbonates the plots of k(obsd) vs [amine] are linear, with the slope (k(N)) independent of pH. The Bronsted plots (log k(N) vs pyridine pK(a)) for these reactions are linear with slopes beta = 0.9 and 1.2 for the pyridinolysis of 1 and 2, respectively. These slopes are consistent with a mechanism through a T(+/-) intermediate on the reaction path, whereby decomposition of T(+/-) to products is the rate-determining step. The k(N) values are larger for the reactions of 1 than those of 2. This is attributed to a larger equilibrium formation of T(+/-) and a larger expulsion rate of the nucleofuge from T(+/-) in the reactions of 1 compared to those of 2.

Effectiveness of infliximab in patients with inflammatory arthritis refractory to conventional treatmentBackground: Tumor necrosis factor antagonists are useful in the treatment of several chronic inflammatory immune mediated diseases. Aim: To assess the effects of infliximab in 21 patients with inflammatory arthropaties, refractary to conventional treatment. Patients and methods: Eleven patients with rheumatoid arthritis, seven with psoriatic arthritis and three with spondyloarthritis were treated. The mean duration of the diseases was 10 years. Infliximab was administered intravenously in a dose of 3 mg/kg body weight. A median of 6 doses in 8 months was administered. Effectiveness was assessed in 19 patients that received three or more doses. Results: Infliximab was effective in 16 patients (10 with rheumatoid arthritis, four with psoriasis and two with spondyloarthritis) and ineffective in three. In responsive patients, a reduction in the number of inflammed joints and morning stiffness and an improvement in functional capacity was observed. Fifteen of the 16 patients perceived an improvement in their health status. This answer was concordant with concomitant medical evaluation in 15. Patients that maintained the treatment felt very well, well or regular, whereas five of six patients that discontinued the treatment felt ill. Thirteen patients had adverse effects. Treatment was discontinued in two patients due to drug induced lupus, allergy in 2, hypertension in one, high costs in three and lack of response in three. Conclusions: Infliximab reduced arthritic activity in 16 of 19 patients with severe treatment refractary arthritis (Rev Méd Chile