Newborn screening for 3‐hydroxy‐3‐methylglutaric aciduria using direct analysis in real‐time mass spectrometry

A novel method utilizing ambient thermal desorption ionization with a direct analysis in real‐time source integrated with mass spectrometry (DART‐MS) was established and applied to the rapid analysis of 3‐hydroxy‐3‐methylglutaric (3‐HMG) acid in the neonatal urine. Instrument parameter settings were optimized to obtain high sensitive and accurate determination of 3‐HMG acid. The use of helium gas heated to temperature of 400°C was observed to permit deprotonation, 3‐HMG acid producing an abundant (M‐H)^? (m/z 161) in the negative ion mode. The calibration curve was determined to be linear over the range of 0.05‐5 mg/L, with the correlation coefficient r = 0.9988 and the relative standard deviations (n = 6) in the range of 1.5‐11.8%. The limit of detection was 0.002 mg/L, and the limit of quantitation was 0.007 mg/L. The recoveries ranged from 88.0% to 123.1%. Four urine samples from patients and four simulated urine samples were investigated. The results of DART‐MS were in agreement with the values determined using established methods at the hospitals. The proposed method demonstrated significant potential in the application of the high‐throughput screening in newborn screening.     

Synthesis and properties of hydroxy tail-terminated cyanobiphenyl liquid crystals

Two series of new hydroxy tail-terminated cyanobiphenyl compounds are described. The 4′-ω-hydroxyalkynyl-4-cyanobiphenyl compounds (1a–1g) were synthesised as the key intermediates to the 4′-?ω-hydroxyalkyl-4-cyanobiphenyl compounds (2a–2g) obtained upon reduction of the acetylenes. Many of these ω-hydroxyalkynyl and ω-hydroxyalkyl cyanobiphenyl compounds exhibit nematic mesophases and they also serve as precursors for the synthesis of other interesting materials. Using density functional theory, we calculate the dipole moment of all relevant ω-hydroxyalkynyl and ω-hydroxyalkyl cyanobiphenyl compounds and find a correlation between the calculated dipole moments and measured crystalline to nematic or isotropic liquid transition temperatures.     

新型芳基丙烯酸酯的合成及生物活性

依据活性亚结构的拼接原理,以Baylis-Hillman加成物为原料,设计并合成了5种新的芳基丙烯酸酯类化合物,经IR、1HNMR和元素分析测试技术确证;温室条件下测试了目标化合物的生物活性。结果发现,这些化合物在600ga.i./hm2的剂量下对供试靶标无杀虫活性;在400ga.i./hm2的剂量下对供试靶标无杀菌活性;在2000ga.i./hm2的剂量下,对阔叶杂草百日草(YOA)、苘麻(VEL)和禾本科杂草稗草(BYG)、马唐(CRG)均具有一定的除草活性。这些化合物结构全新,分子中具有多个可供修饰的基团,可作为除草活性的新型先导化合物提供进一步的优化。     

一种测定·OH产生与清除的新化学发光体系

报道一种产生和检测·OH的新化学发光体系。该体系由50μL2.0mmol/LCuCl,50μL1 %(φ)H2O2,50μL1.5mmol/L邻菲啉,0.05mol/LNa2CO3-NaHCO3 缓冲液(pH9.60)组成,反应液总体积为1.0mL。该体系简便、稳定、灵敏、特异性强,值得推广。     

Excited state (formal) intramolecular proton transfer (ESIPT) in p-hydroxyphenyl ketones mediated by water

Evidence is presented that show p-hydroxyphenyl ketones 6–8 undergo excited state intramolecular proton transfer (ESIPT, via the singlet excited state), mediated by water, which formally transfers the phenol proton to the carbonyl oxygen of the ketone. ESIPT was not observed in neat CH₃CN. The ESIPT process in aqueous media generates the corresponding p-quinone methides 9–11 (and the corresponding conjugate bases (phenolate ions) 12–14), as detected by laser flash photolysis (LFP). It competes effectively with intersystem crossing to the excited triplet state. The respective p-methoxyphenyl ketones 15 and 16 failed to undergo the reaction consistent with the expected lack of proton transfer in these systems. Results for the biphenyl ketone 8 indicate that formal ESIPT can also take place over an extended range, suggesting that the process is likely general for all p-hydroxyaromatic ketones which opens up the possibility for designing photoswitchable processes based on this general phenomenon.     

土壤和水体中可溶性铝硅酸盐的形成及其环境意义

阐述了土壤环境中铝的释放，水解，单体和多聚体羟基铝，铝硅酸盐复合离子ｐｒｏｔｏ－ｉｍｏｇｏｌｉｔｅ的形成和影响因素及其生态效应。     

夏桑菊提取物对自由基的清除作用

探讨夏桑菊提取的最佳工艺条件,并比较提取物在不同提取剂中对羟自由基的清除作用。结果表明夏桑菊提取物除石油醚层外,对羟自由基都有一定的清除作用,其中乙酸乙酯提取物清除作用最强。     

Synthesis and Biological Activity of O,O′-Dialkyl 5-Aryl-1-Hydroxy-3-Methyl-2E,4E-Pentadienylphosphonates

A series of unsaturated f -hydroxy phosphonates were synthesized by the addition reactions of dialkyl phosphites with 5-aryl-3-methyl-2E, 4E-pentadienaldehydes. The structures of all new compounds have been confirmed by 1 H NMR, 31 P NMR, and IR spectroscopy and by elemental analysis or MS. The bioassays showed that some of these compounds exhibit certain inhibitory activity on the elongation of wheat coleoptile.     

Highly Regioselective One‐Pot Synthesis of 7‐Hydroxy‐6‐methylphthalide from 3‐Hydroxy‐4‐methylbenzylalcohol

7‐Hydroxy‐6‐methylphthalide 2 was synthesized with high regioselectivity and moderate yield using a novel one‐pot synthesis that employed 3‐hydroxy‐4‐methylbenzylalcohol 1 and formaldehyde in the presence of tin(IV) chloride as catalyst and triethylamine as base. The proposed mechanism of the formation of 2 involves ortho‐formylation followed by hemiacetal formation and oxidation.     

5′-Epimeric 3′-deoxy-3′,4′-didehydronucleoside-5′-C-phosphonates: synthesis and structural assignment by NMR and X-ray analyses

Epimeric 5′-(RS) dialkyl 3′-deoxy-3′,4′-didehydro-5′-C-phosphonates were prepared by nucleophilic addition of various dialkyl phosphites to 3′-deoxy-3′,4′-didehydronucleoside-5′-aldehydes. Whereas direct NMR configuration assignment for the C5′ atom bearing the phosphoryl and hydroxy groups using the J (P,H4′) and J (H5′,H4′) coupling constants is impossible due to the absence of the H4′ atom, successful separation, crystallisation and X-ray crystallographic analysis of a pair of epimeric 5′-C-phosphonates, followed by correlation with a series of NMR parameters, led to efficacious configuration assignment of individual epimers in the mixtures.