Crystal Structure and Biological Activities of (R)-N′-[2-(4-Methoxy-6-chloro)-pyrimidinyl]-N-[3-methyl-2-(4-chlorophenyl)butyryl]-urea

The title compound （R）-N′-[2-（4-methoxy-6-chloro）-pyrimidyl]-N-[3-methyl-2-（4- chlorophenyl）butyryl]-urea has been synthesized, and its crystal structure and biological behaviors were studied. Crystallographic data： C17H18C12N4O3, Mr = 397.25, monoclinic, space group P21/c, a = 12.331（2）, b = 14.025（3）, c = 23.085（5） A, β = 99.607（4）°, Z = 8, V = 3936.2（13） A3, Dc = 1.341 g/cm^3, F（000） = 1648, R = 0.0718, wR = 0.1585 and/t（MoKα） = 0.353 mm^-1. The preliminary biological tests showed that the title compound has definite insecticidal and fungicidal activities.

A New Chiral Synthesis of Naturally Occurring (-)-(S)-4-Hydroxy-2-pyrrolidinone

A new and convenient chiral synthesis of naturally occurring (-)-(S)-4-hydroxy-2-pyrrolidinone from (S)-malic acid was reported.

A New Sesquiterpene-substituted Benzoic Acid from the Brown Alga Dictyopteris divaricata

A new sesquiterpene-substituted benzoic acid has been isolated from the brown Alga Dictyopteris divaricata Okam.. Its structure was elucidated as 3-[(2-hydroxy-2,5,5,8a-tetra- methyldecahydro-1-naphthalenyl)methyl]-4-hydroxybenzoic acid, named dictyvaric acid on the basis of spectroscopic methods including IR, HRFABMS, 1D and 2D NMR techniques.

A new pyrrolidone derivative from Pistacia chinensis

A new N-phenyl-pyrrolidone derivative had been isolated from Pistacia chinesis Bunge. Its structure was elucidated as 4-hydroxy-5-（2-oxo-1-pyrrolidinyl）-benzoic acid, named pistaciamide on the basis of the 1D-NMR, DEPT, HMQC and HMBC spectroscopic techniques. 2007 Xi Kui Liu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

A systematic review of metabolism of methionine sources in animals:One parameter does not convey a comprehensive story

The goal of this review article,based on a systematic literature search,is to critically assess the state of knowledge and experimental methodologies used to delineate the conversion and metabolism of the 2 methionine(Met)sources DL-methionine(DL-Met)and DL-2-hydroxy-4-(methylthio)butanoic acid(HMTBa).The difference in the chemical structures of HMTBa and DL-Met indicates that these molecules are absorbed and metabolized differently in animals.This review explores the methodologies used to describe the 2-step enzymatic conversion of the 3 enantiomers(D-HMTBa,L-HMTBa and D-Met)to L-Met,as well as the site of conversion at the organ and tissue levels.Extensive work was published documenting the conversion of HMTBa and D-Met into L-Met and,consequently,the incorporation into protein using a variety of in vitro techniques,such as tissue homogenates,cell lines,primary cell lines,and everted gut sacs of individual tissues.These studies illustrated the role of the liver,kidney,and intestine in the con-version of Met precursors into L-Met.A combination of in vivo studies using stable isotopes and infusions provided evidence of the wide conversion of HMTBa to L-Met by all tissues and how some tissues are net users of HMTBa,whereas others are net secreters of L-Met derived from HMTBa.Conversion of D-Met to L-Met in organs other than the liver and kidney is poorly documented.The methodology cited in the literature to determine conversion efficiency ranged from measurements of urinary,fecal,and respiratory excretion to plasma concentration and tissue incorporation of isotopes after intraperitoneal and oral in-fusions.Differences observed between these methodologies reflect differences in the metabolism of Met sources rather than differences in conversion efficiency.The factors affecting conversion efficiency are explored in this paper and are mostly associated with extreme dietary conditions,such as noncommercial crystalline diets that are very deficient in total sulfur amino acids with respect to requirements.Impli-cations in the diversion of the 2 Met sources toward transsulfuration over transmethylation pathways are discussed.The strengths and weaknesses of some methodologies used are discussed in this review.From this review,it can be concluded that due to the inherent differences in conversion and metabolism of the 2 Met sources,the experimental methodologies(e.g.,selecting different organs at different time points or using diets severely deficient in Met and cysteine)can impact the conclusions of the study and may explain the apparent divergences of conclusion found in the literature.It is recommended when con-ducting studies or reviewing the literature to properly select the experimental models that allow for differences in how the 2 Met precursors are converted to L-Met and metabolized by the animal to enable a proper comparison of their bioefficacy.

Dietary methionine sources and levels modulate the intestinal health status of broiler chickens

Given the key role of methionine in biological processes,adequate methionine should be provided to meet the nutritional requirements.DL-2-hydroxy-4-(methylthio)-butanoic acid(DL-HMTBA)has been considered as an important source of methionine.However,the effects of different sources and levels of methionine on the intestinal health status have not been clarified yet.An experiment was carried out to investigate the effects of different dietary sources and levels of methionine on the intestinal epithelial barrier,inflammatory cytokines expression,ileal morphology,microbiota composition,and cecal short chain fatty acids(SCFA)profiles.For this purpose,720 male Arbor Acre broiler chicks at 1 d old were randomly assigned to a 2×3 factorial arrangement with 2 methionine sources(DL-methionine and DLHMTBA)and 3 total sulfur amino acids(TSAA)levels(80%,100%,and 120%of Arbor Acre recommendation).The results showed that DL-HMTBA supplementation promoted intestinal physical barrier at both gene expression level of claudin-1 and serum diamine oxidase level(P<0.05),and the inflammatory cytokine IL-6 m RNA expression was down-regulated by dietary DL-HMTBA supplementation compared with the DL-methionine group(P<0.05).Meanwhile,an upregulated gene expression of claudin-1 and zonula occluden-1(ZO-1)were observed in the low-TSAA treatment on d 14(P<0.05),whereas this treatment increased the expression of IL-1βand IL-6(P<0.05).Villus height to crypt depth ratio was high(P<0.05)in the middle-level TSAA group.Furthermore,DL-HMTBA supplementation optimized the microbiota of the ileum especially the relative abundance of Lactobacillus,where the digestion and absorption were completed,and elevated the concentrations of SCFA(acetate,propionate,and butyrate)in the cecal content on d 21(P<0.01).In conclusion,dietary DL-HMTBA supplementation improved the intestinal barrier function,immune homeostasis and optimized the microbiota to promote intestinal health status in broiler chickens.

羟基蛋氨酸及其钙盐的合成研究进展

羟基蛋氨酸钙是复方α-酮酸片中一个重要成分,可防止氨基酸缺乏和改善代谢紊乱,对肾功能衰竭具有一定的疗效,并对钙代谢和继发性甲状旁腺功能亢进都具有益作用,同时也是重要的有机合成、药物合成及生物合成中间体。本文对近年来羟基蛋氨酸及其钙盐的合成方法进行了综述。重点介绍了氰醇水解法、蛋氨酸转化法、酮酸转化法、酮醇氧化法、氰代磷酸二乙酯法和α-羟基-γ-丁内酯法等在羟基蛋氨酸及其钙盐合成中的应用。