sp3 -Rich Heterocycle Synthesis on DNA: Application to DNA-Encoded Library Production.

DNA encoded library (DEL) synthesis represents a convenient means to produce, annotate and store large collections of compounds in a small volume. While DELs are well suited for drug discovery campaigns, the chemistry used in their production must be compatible with the DNA tag, which can limit compound class accessibility. As a result, most DELs are heavily populated with peptidomimetic and sp2 -rich molecules. Herein, we show that sp3 -rich mono- and bicyclic heterocycles can be made on DNA from ketochlorohydrin aldol products through a reductive amination and cyclization process. The resulting hydroxypyrrolidines possess structural features that are desirable for DELs and target a distinct region of pharmaceutically relevant chemical space.

Preparation and Uses of Chlorinated Glycerol Derivatives.

Crude glycerol (C3H8O3) is a major by-product of biodiesel production from vegetable oils and animal fats. The increased biodiesel production in the last two decades has forced glycerol production up and prices down. However, crude glycerol from biodiesel production is not of adequate purity for industrial uses, including food, cosmetics and pharmaceuticals. The purification process of crude glycerol to reach the quality standards required by industry is expensive and dificult. Novel uses for crude glycerol can reduce the price of biodiesel and make it an economical alternative to diesel. Moreover, novel uses may improve environmental impact, since crude glycerol disposal is expensive and dificult. Glycerol is a versatile molecule with many potential applications in fermentation processes and synthetic chemistry. It serves as a glucose substitute in microbial growth media and as a precursor in the synthesis of a number of commercial intermediates or fine chemicals. Chlorinated derivatives of glycerol are an important class of such chemicals. The main focus of this review is the conversion of glycerol to chlorinated derivatives, such as epichlorohydrin and chlorohydrins, and their further use in the synthesis of additional downstream products. Downstream products include non-cyclic compounds with allyl, nitrile, azide and other functional groups, as well as oxazolidinones and triazoles, which are cyclic compounds derived from ephichlorohydrin and chlorohydrins. The polymers and ionic liquids, which use glycerol as an initial building block, are highlighted, as well.

Total Synthesis and Configurational Assignment of Ascospiroketal†A.

The total synthesis of the marine fungus-derived natural product ascospiroketal is described. This concise synthesis relies on a unique Ag(I) -promoted tandem cascade cyclization that provides direct access to the correctly configured tricyclic core of the natural product from a linear precursor. The synthesis of candidate stereostructures of ascospiroketal A allowed for the confident assignment of both the relative and absolute stereochemistry of this unusual octaketide.

Oleic acid chlorohydrin, a new early biomarker for the prediction of acute pancreatitis severity in humans.

BACKGROUND: The early prediction of the severity of acute pancreatitis still represents a challenge for clinicians. Experimental studies have revealed the generation of specific halogenated lipids, in particular oleic acid chlorohydrin, in the early stages of acute pancreatitis. We hypothesized that the levels of circulating oleic acid chlorohydrin might be a useful early prognostic biomarker in acute pancreatitis in humans. METHODS: In a prospective, multicenter cohort study, plasma samples collected within 24 h after presentation in the emergency room from 59 patients with acute pancreatitis and from 9 healthy subjects were assessed for oleic acid chlorohydrin levels. RESULTS: Pancreatitis was mild in 30 patients, moderately severe in 16 and severe in 13. Oleic acid chlorohydrin levels within 24 h after presentation were significantly higher in patients that later progressed to moderate and severe acute pancreatitis. Using 7.49 nM as the cutoff point, oleic acid chlorohydrin distinguished mild from moderately severe-to-severe pancreatitis with high sensitivity/specificity (96.6/90.0%) and positive/negative predictive values (90.3/96.4%). Using 32.40 nM as the cutoff value sensitivity, specificity, positive and negative predictive values were all 100% for severe acute pancreatitis. It was found to be a better prognostic marker than BISAP score, hematocrit at 48 h, SIRS at admission, persistent SIRS or C-reactive protein at 48 h. CONCLUSIONS: Oleic acid chlorohydrin concentration in plasma is elevated in patients with acute pancreatitis on admission and correlates with a high degree with the final severity of the disease, indicating that it has potential to serve as an early prognostic marker for acute pancreatitis severity.

Biotransformation of 6-dehydroprogesterone with Aspergillus niger and Gibberella fujikuroi.

Microbial transformation of 6-dehydroprogesterone (1) with Aspergillus niger yielded three new metabolites, including 6ß-chloro-7α,11α-dihydroxypregna-4-ene-3,20-dione (2), 7α-chloro-6ß,11α-dihydroxypregna-4-ene-3,20-dione (3), and 6α,7α-epoxy-11α-hydroxypregna-4-ene-3,20-dione (4), and two known metabolites; 6α,7α-epoxypregna-4-ene-3,20-dione (5), and 11α-hydroxypregna-4,6-diene-3,20-dione (6). Compounds 2, and 3 contain chlorohydrin moiety at C-6, and C-7, respectively. The biotransformation of 1 with Gibberella fujikuroi yielded a known compound, 11α,17ß-dihydroxyandrosta-4,6-dien-3-one (7).

Polyoxygenated cyclohexene derivatives isolated from Dasymaschalon sootepense and their biological activities.

Six new naturally occurring polyoxygenated cyclohexene derivatives together with eight related known derivatives, two known alkaloids, and two known flavonoid derivatives were isolated from bioassay-guided fractionation of the ethyl acetate extract of the leaves and twigs of Dasymaschalon sootepense. The structure elucidation and determination of absolute configurations were established by various spectroscopic methods, X-ray diffraction techniques as well as comparison with the literature data. Several isolated compounds were evaluated for their cytotoxic, anti-HIV-1 RT and anti-inflammatory activities.

Toxicity of 1,2-dichloroethane and its metabolites on human astrocytes / 中国职业医学

OBJECTIVE: To explore the toxicity of 1,2-dichloroethane( 1,2-DCE) and its metabolites on human astrocytes( HAs). METHODS: Different doses of 1,2-DCE( 5. 00,10. 00,25. 00,50. 00 and 100. 00 mmol/L),2-chlorohydrins( 5. 00,25. 00,50. 00,100. 00 and 200. 00 mmol/L),2-chloroacetaldehyde( 1. 00,5. 00,10. 00,20. 00 and 50. 00 mmol / L) and chloroacetic acid( 0. 01,0. 05,0. 10,0. 50 and 1. 00 mmol / L) were used for treating HAs in vitro during their logarithmic phase. After 24 hours of culture,the morphology of HAs was observed by fluorescent inverted phase contrast microscope. The survival rate and the inhibition ratio of HAs were detected by CCK-8 colorimetry to estimate the50% inhibiting concentration in 24 hours( 24 h-IC50). The apoptosis of HAs was tested by double-labeling and flow cytometry using Annexin Ⅴ-fluorescein isothiocyanate and propidium iodide. RESULTS: The morphology of HAs changed in varying degrees after 24 hours exposure to 1,2-DCE,2-chlorohydrins,2-chloroacetaldehyde and chloroacetic acid. The changes included smaller size of cells,pseudopodia tapering,increased intracellular particles and suspension of circular cells and decreased transparency of cells. With the increasing does of 1,2-DCE,2-chlorohydrins,2-chloroacetaldehyde and chloroacetic acid exposure,the survival rates of HAs decreased( P < 0. 01),while its inhibition ratios increased( P <0. 01). They all showed dose-effect relationship. 24 h-IC50 of the above 4 chemicals were 56. 25,235. 00,26. 43 and1. 38 mmol / L,respectively. The 1,2-DCE,2-chlorohydrins and chloroacetic acid could induce the apoptosis of HAs and the apoptosis rate of HAs was positively correlated with the 3 kinds of chemicals( P < 0. 01). CONCLUSION: 1,2-DCE and its metabolites 2-chloroacetaldehyde,2-chlorohydrins and chloroacetic acid can lead to toxic damage and induce the apoptosis of HAs. Chloroacetic acid has the strongest toxicity among the metabolites.

EFFECTS OF ALPHA-CHLOROHYDRIN COMBINED WITH GLYCIDOL ON THE ULTRASTRUCTURE OF CAPUT EPIDIDYMIS, LIVER AND KIDNEY IN MALE RATS AFTER LONG-TREATMENT WITH LOW DOSAGE / 解剖学报

It was reported that a complete antifertility action of alpha-chlorohydrin in combination with glycidol in male rats after a daily oral dose of 5mg/kg and 75mg/kg respectively for two days. Simultaneously some ultrastructural changes including mitochondrial swelling, atrophy of Golgi complex, decreasing in pinocytotic vesicles and stereocilia were found in principal cells of epididymis within 3 days after medication.In this experiment the animals received 3, 6 and 9 courses of treatment respectively, each course included two days of administration with a daily dose mentioned above and eight days of cessation of medication.The specimens of initial segment of epididymis, liver and kidney were taken at the end of 3 rd, 6 th and 9th courses of treatment for electron microscopy.The principal cells of initial segment of epididymis revealed a normal feature at the end of 3 rd and 9 th course of treatment. But at the end of 6 th course of treatment, the atrophy of Golgi complex and the decrease in stereocilia and pinocytotic vesicles were found in some principal cells.Any ultrastructural changs of sperms in the initial segment were not found by electron microscope.There was also mitochondrial changes with striking increase in the density of the matrix and reduction of size in some liver cells at the end of 6 th course of treatment, but not at the end of 3 rd or 9 th course of treatment. The epithelial cells of nephron in all the specimens revealed a normal ultrastructural feature.The results suggest that the ultrastructural changes of the principal cells and the liver cells induced by the mixture of the drugs could be recovered at the end of treatments.