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Methyl 4-(1-methylpyrrolidin-2-yl)-3-oxobutanoate and hygrine are important biosynthetic intermediates for tropane alkaloids. We have developed a concise method to synthesize these two compounds from the key intermediate N-methylpyrrolinium cation. Methyl 4-(1-methylpyrrolidin-2-yl)-3-oxobutanoate and hygrine were obtained in four and six steps from commercially available 4,4-diethoxybutylamine with overall yields of 42% and 25%, respectively. Key words: methyl 4-(1-methylpyrrolidin-2-yl)-3-oxobutanoate, hygrine, biosynthetic intermediate, tropane alkaloid, N-methylpyrrolinium cation. Le 4-(1-methylpyrrolidin-2-yl)-3-oxobutanoate de methyle et l'hygrine sont des intermediaires biosynthetiques importants pour la synthese des alcaloides tropaniques. Nous avons mis au point une methode pour synthetiser ces deux composes tk;4a partir du cation N-methylpyrrolinium comme intermediaire cle. Nous avons obtenu le 4-(1-methylpyrrolidin-2-yl)-3-oxobutanoate de methyle et l'hygrine en quatre et six etapes, respectivement, a partir de la 4,4-diethoxybutylamine, qui est commercialement disponible, avec des rendements respectifs de 42 % et de 25 %. [Traduit par la Redaction] Mots-cles : 4-(1-methylpyrrolidin-2-yl)-3-oxobutanoate de methyle, hygrine, intermediaire biosynthetique, alcaloide tropanique, cation N-methylpyrrolinium., Introduction Tropane alkaloids, a family of important natural products found in plants throughout the world, have attracted growing attention becauseoftheir significant biological and pharmacological activity. (1-5) These alkaloids contain complex [...]

Estra-4,9-diene-3,17-dione, an important pharmaceutical intermediate, was synthesized by a three-step sequence from [delta]-lactone 1 in 23.4% overall yield. Reaction of [delta]-lactone 1 and Grignard reagent 2 followed by treatment with Jones reagent resulted in precursor 4. The domino cyclization reaction of 4 with piperidinium acetate gave estra-4,9-diene-3,17-dione. Key words: estra-4,9-diene-3,17-dione, pharmaceutical intermediate, [delta]-lactone, Grignard reaction, Jones reagent, domino cyclization reaction. Nous avons synthétisé l'estra-4,9-diène-3,17-dione, un intermédiaire pharmaceutique d'importance, en trois étapes séquentielles à partir de la [delta]-lactone 1 dans un rendement global de 23,4 %. La réaction entre la [delta]-lactone 1 et le réactif de Grignard 2, suivie d'un traitement par le réactif de Jones a produit le précurseur 4. La réaction de cyclisation domino de l'intermédiaire 4 avec l'acétate de pipéridinium a donné l'estra-4,9-diène-3,17-dione. [Traduit par la Rédaction] Mots-clés : estra-4,9-diène-3,17-dione, intermédiaire pharmaceutique, [delta]-lactone, réaction de Grignard, réactif de Jones, réaction de cyclisation domino., Introduction Estra-4,9-diene-3,17-dione is an important pharmaceutical intermediate in the synthesis of steroids with progestagenic activity (1-3) such as Mifepristone (4-7) and Ulipristal Acetate (8-11) (Fig. 1). Thus, a convenient construction [...]

Liver cirrhosis occurs as a consequence of many chronic liver diseases that are prevalent worldwide. Here we characterize the gut microbiome in liver cirrhosis by comparing 98 patients and 83 healthy control individuals. We build a reference gene set for the cohort containing 2.69 million genes, 36.1% of which are novel. Quantitative metagenomics reveals 75,245 genes that differ in abundance between the patients and healthy individuals (false discovery rate < 0.0001) and can be grouped into 66 clusters representing cognate bacterial species; 28 are enriched inpatients and 38 in control individuals. Most (54%) of the patient-enriched, taxonomically assigned species are of buccal origin, suggesting an invasion of the gut from the mouth in liver cirrhosis. Biomarkers specific to liver cirrhosis at gene and function levels are revealed by a comparison with those for type 2 diabetes and inflammatory bowel disease. On the basis of only 15 biomarkers, a highly accurate patient discrimination index is created and validated on an independent cohort. Thus microbiota-targeted biomarkers may be a powerful tool for diagnosis of different diseases., Cirrhosis is an advanced liver disease resulting from acute or chronic liver injury, including alcohol abuse, obesity and hepatitis virus infection. The prognosis for patients with decompensated liver cirrhosis is [...]

Background The relationship between Klebsiella pneumoniae and nosocomial and community-acquired infections is well known, and K. pneumoniae resistance to most antibiotics is increasing worldwide. In contrast, tigecycline remains active against many bacterial strains, and serves as a last resort for treating multi-drug resistant bacterial infections. That tigecycline nonsusceptibility among K. pneumoniae isolates has been reported worldwide is worrying. However, the mechanisms of tigecycline resistance in K. pneumoniae are less well known. We report the genome sequence and genomic characterization of tigecycline-resistant K. pneumoniae strain 5422 isolated from the bile samples of a patient with cholangiocarcinoma. Results We sequenced the K. pneumoniae strain 5422 genome using next-generation sequencing technologies. Sequence data assembly revealed a 5,432,440-bp draft genome and 57.1% G + C content, which contained 5397 coding sequences. The genome has extensive similarity to other sequenced K. pneumoniae genomes, but also has several resistance-nodulation-cell division (RND) efflux pump genes that may be related to tigecycline resistance. Conclusions K. pneumoniae strain 5422 is resistant to multiple antibiotics. The genome sequence of the isolate and comparative analysis with other K. pneumoniae strains presented in this paper are important for better understanding of K. pneumoniae multi-drug resistance. The RND efflux pump genes identified in the genome indicate the presence of an antibiotic resistance mechanism prior to antibiotics overuse. The availability of the genome sequence forms the basis for further comparative analyses and studies addressing the evolution of the K. pneumoniae drug resistance mechanism and the K. pneumoniae transcriptome. Keywords: Tigecycline-resistant, Klebsiella pneumoniae, Cholangiocarcinoma, Next-generation sequencing, Comparative genomics, Author(s): Beiwen Zheng[sup.1,2] , Ang Li[sup.1,2] , Xiawei Jiang[sup.1,2] , Xinjun Hu[sup.1,2] , Jian Yao[sup.1,2] , Lina Zhao[sup.1,2] , Jinru Ji[sup.1,2] , Min Ye[sup.1,2] , Yonghong Xiao[sup.1,2] and Lanjuan Li[sup.1,2] [...]