Carbohydrate as a chiral template: optical resolution of N-tert-butanesulfinamides

N-tert-butanesulfinamides, a class of amines bearing a sulfinyl group attached to nitrogen, exhibit pyramidal bonding where the non-bonded electron pair located at the sulfur atom acts as a fourth ligand. These compounds are configurationally sufficiently stable to be separated into R- and S- enantiomers. Enantiopure N-tert-butanesulfinamides are important auxiliaries in asymmetric synthesis, and some of them also have useful biological properties. In this paper, a new efficient strategy for enantioselective synthesis of N-tert-butanesulfinamides with very goods yields and excellent enantiomeric excess via the hydrolysis reaction of N-glycosidic bonds that were formed from D-ribose, under basic conditions was described. Keywords. N-tert-butanesulfinamide, N-glycoside, D-ribose, enantiomer, asymmetric synthesis

CSA: Thực hành nông nghiệp thông minh với khí hậu ở Việt Nam

During the last five years, Vietnam has been one of the countries most affected by climate change. Severe typhoons, flooding, cold spells, salinity intrusion, and drought have affected agriculture production across the country, from upland to lowland regions. Fortunately for Vietnam, continuous work in developing climate-smart agriculture has been occurring in research organizations and among innovative farmers and entrepreneurs. Application of various CSA practices and technologies to adapt to the impact of climate change in agriculture production have been expanding. However, there is a need to accelerate the scaling process of these practices and technologies in order to ensure growth of agriculture production and food security, increase income of farmers, make farming climate resilient, and contribute to global climate change mitigation. This book aims to provide basic information to researchers, managers, and technicians and extentionists at different levels on what CSA practices and technologies can be up scaled in different locations in Vietnam

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

Développements en synthèse organique et en synthèse asymétrique de réactions tandem isomérisation-aldolisation et isomérisation-Mannich à partir d'alcools allyliques

Ces travaux de thèse s'inscrivent dans la continuité des études du laboratoire sur la réaction tandem isomérisation-aldolisation à partir d alcools allyliques et/ou de lactols. Dans le premier chapitre nous avons montré que cette réaction pouvait être étendue avec succès à une version tandem isomérisation-Mannich en partant de N-sulfonylimines. Le deuxième chapitre concerne l extension de cette réaction à sa version asymétrique, en utilisant cette fois des N-sulfinylimines chirales. Ceci a permis la synthèse, sous forme énantiopure, de b-aminocétones contenant une fonction amine primaire libre, molécules très rarement décrites dans la littérature. Cette méthode a été appliquée à la synthèse totale d intermédiaires clés pour préparer des produits naturels bioactifs: Nikkomycines, Funebrine Dans le troisième chapitre, nous décrivons l extension de la réaction tandem isomérisation-Mannich en série intramoléculaire et son application à la synthèse asymétrique d aminocyclitols. Enfin, le quatrième chapitre décrit nos résultats préliminaires visant à étendre la réaction tandem isomérisation-aldolisation à des alcools allyliques avec un groupe silylé en position vinylique.This thesis is an extension of studies regarding the tandem isomerisation-aldolisation starting from allylic alcohols/lactols, carried out previously in our group. The first chapter deals with the successful development of the tandem isomerisation-Mannich reaction, starting from N-sulfonylimines. The second chapter deals with the extension of this reaction to asymmetric synthesis by using chiral N-sulfinylimines. It has been used for the preparation of b-aminoketones with a free amino group, a type of molecules rarely reported in literature. Further, it has been applied to the total synthesis of key intermediates for the preparation of bioactive natural products: Nikkomycins, Funebrine The third chapter relates the application of tandem intramolecular isomerisation-Mannich for the asymmetric synthesis of aminocyclitols. The last chapter deals with our preliminary results on the extension of the tandem isomerisation-aldolisation to allylic alcohols bearing a silyl group on the double bond.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

Synthesis of β-aminocyclohexanones and β-aminocyclohexanols through an intramolecular tandem isomerization-Mannich reaction as a key step

International audienceNew β-aminocyclohexanones and β-aminocyclohexanols, with a primary amino group, have been obtained by a short and efficient sequence involving an intramolecular tandem isomerization-Mannich reaction as the key step. This methodology takes advantage of tert-butanesulfinyl protection of the nitrogen atom

Intramolecular Tandem Isomerization-Mannich Reaction as a New Route Towards Aminocyclopentitols

International audienceA new efficient synthetic strategy has been developed to prepare aminocyclopentitols. It is based on an iron-catalyzed tandem isomerization-Mannich reaction and uses chiral N-tert-butanesulfinamide as a chiral auxiliary. This methodology has been applied to the enantiocontrolled synthesis of a mannostatin A analogue, as well as isomers of known fucosidase and glycosidase inhibitors

Synthesis of β-aminocyclohexanones and β-aminocyclohexanols through an intramolecular tandem isomerization-Mannich reaction as a key step

International audienceNew β-aminocyclohexanones and β-aminocyclohexanols, with a primary amino group, have been obtained by a short and efficient sequence involving an intramolecular tandem isomerization-Mannich reaction as the key step. This methodology takes advantage of tert-butanesulfinyl protection of the nitrogen atom

A New Approach for the Synthesis of Sotolon in Racemic and Enantioenriched Forms

International audienceSotolon (3-hydroxy-4,5-dimethyl-2(5H)-furanone) has been synthezised both in racemic and enantioenriched forms by a short sequence involving intramolecular tandem isomerization-aldolisation and tandem izomerization/Mannich reactions as key steps. Optically active Sotolon has been obtained by using (S)-N-tert-butane sulfinimine as a chiral starting material

Base-catalyzed multicomponent access to quinoxalin-2-thiones from o -phenylenediamines, aryl ketones and sulfur

International audienceQuinoxalin-2-thiones were readily synthesized from o -phenylenediamines, ketones and sulfur. The reactions proceeded under simple and mild conditions with chromatography-free purification and were amenable to large-scale synthesis

Membrane distillation-liquid desiccant air-conditioning for thermal comfort in buildings

Increasing demand for thermal comfort in buildings together with the urgent need for reducing greenhouse gas emissions has resulted in significant technological advancement in the air-conditioning industry, most notably including the development of the liquid desiccant air-conditioning (LDAC) process. This innovative process involves two stages, namely air dehumidification and liquid desiccant solution regeneration, and its dehumidification capacity is regulated by the efficiency of liquid desiccant solution regeneration. Membrane distillation (MD) has been increasingly explored for regeneration of liquid desiccant solutions in LDAC systems owing to its notable advantages including excellent membrane rejection, resilience to hypersalinity, and effective incorporation of low-grade waste heat and solar thermal energy. Despite these advantages, MD regeneration of liquid desiccant solutions has been demonstrated only at the lab-scale level using direct contact membrane distillation (DCMD) and vacuum membrane distillation (VMD) configurations for manifestation of their technical feasibility. Although these lab-scale demonstrations have arguably paved the way for progress on the MD regeneration of liquid desiccant solutions, more studies at the pilot or large-scale level are required to realize this MD strategic application