Synthesis Of Sulfur-containing Compounds Research Articles

Effect of MgSO<sub>4</sub> nutrition on Theobroma cacao L. susceptibility to Phytophthora megakarya infection

A new strategy to reduce the severity of black pod disease (BPD) in T. cacao plants using MgSO<sub>4</sub> nutrition was investigated. The dynamics of the tolerance to BPD of 18 susceptible T. cacao plantlets coming from the cross (♀SNK64 × ♂UPA14) was monitored during weekly (8 weeks) supply of MgSO<sub>4</sub> into the soil. Prior to MgSO<sub>4</sub> application, disease scores of the 18 plantlets (in six sets of three plantlets per set) were varying between 3.5 (susceptible) and 5 (highly susceptible). After MgSO<sub>4 </sub>application, a substantial decrease in disease scores was observed compared to the control. The percentage of disease tolerance gain of plantlets versus MgSO<sub>4</sub> supplied (0–2.96 g) presented a quasi-hyperbolic curve with asymptotic line corresponding to 60% (day 28) and 70% (day 56). Cysteine content was not significantly different between the six triplets before MgSO<sub>4 </sub>nutrition. On days 28 and 56 of MgSO<sub>4</sub> supplementation, cysteine content presented a pattern similar to the tolerance gain of plantlet sets. The monitoring of glutathione content versus MgSO<sub>4</sub> supplementation (compared to day 0) showed sigmoid (day 28) and hyperbolic (day 56) curves which were associated with defined mathematical laws determined by MALAB software. Negative and highly significant correlations were observed between disease scores, cysteine and glutathione contents in leaves while positive and highly significant correlations were observed between cysteine and glutathione contents in leaves. These data might mean that MgSO<sub>4</sub> nutrition significantly improved the tolerance of T. cacao. The mechanism of tolerance improvement might be associated with the synthesis of sulphur-containing compounds (cysteine and glutathione) which might be directly or indirectly used by T. cacao against P. megakarya.

ChemInform Abstract: Recent Advances in C—S Bond Formation via C—H Bond Functionalization and Decarboxylation

AbstractReview: [95 refs.

Recent advances in C-S bond formation via C-H bond functionalization and decarboxylation.

The development of mild and general methods for C-S bond formation has received significant attention because the C-S bond is indispensable in many important biological and pharmaceutical compounds. Early examples for the synthesis of C-S bonds are generally limited to the condensation reaction between a metal thiolate and an organic halide. Recent chemical approaches for C-S bond formation, based upon direct C-H bond functionalization and decarboxylative reactions, not only provide new insights into the mechanistic understanding of C-S coupling reactions but also allow the synthesis of sulfur-containing compounds from more effective synthetic routes with high atom economy. This review intends to explore recent advances in C-S bond formation via C-H functionalization and decarboxylation, and the growing opportunities they present to the construction of complex chemical scaffolds for applications encompassing natural product synthesis, synthetic methodology development, and functional materials as well as nanotechnology.

Studies on the sulfur metabolism of cows on protein-free and low-protein feed

The influence of purified, protein-free feed with urea and ammonium salts as nitrogen sources (0-feed) and of non-purified, urea-rich, low-protein feeds (ULP-feed) on the sulfur metabolism of cows has been studied by determining the contents of sulfur fractions in faeces, urine, milk, blood and rumen fluid. The sulfur of 0-feed was composed entirely of inorganic sulfate. During balance trials the N:S ratio in the feed varied from 6.1 to 9.5, and the sulfur content from 0.22 to 0.31 % of the dry matter. In every trial (seven with 0-feed and two with ULP-feed), of five or seven days duration, the cows were in high-positive sulfur balance. The 0-cows excreted a greater proportion of their total sulfur output via urine than the ULP-cows. The excretion of inorganic sulfate sulfur, as a proportion of the urinary and faecal sulfur, was greater for 0-cows than for ULP- or NorP-cows (cows on normal, protein-rich feed); the opposite was the case with regard to the excretion of ester sulfate sulfur and neutral sulfur. The sulfur contents of milk and blood showed only minor inter-feed differences. The sulfate content in the rumen fluid of the 0-cow rose rapidly after the commencement of feeding and then fell quite rapidly. We conclude tentatively that in the rumen of the 0-cow hydrogen sulfide is generated so quickly that the whole of it cannot be used for the synthesis of sulfur-containing compounds, a considerable proportion of it being lost in eructations or excreted as inorganic sulfates in the urine.