26063-00-3Relevant articles and documents
Stereospecific Reduction of 2,3-Epoxybutanoic Acid. Synthesis of (R,R)- and (S,S)-3-Hydroxybutanoic-2-d Acid and S-tert-Butyl 3-Acetoxythiobutanoate-2-d
Mohrig, Jerry R.,Vreede, Pieter J.,Schultz, Steve C.,Fierke, Carol A.
, p. 4655 - 4658 (1981)
Reduction of 2,3-epoxybutanoic acid (2) with sodium borodeuteride provides a stereospecific synthesis of 3-hydroxybutanoic-2-d acid (3).This route should be of general utility in stereospecific syntheses of metabolically important 3-hydroxyalkanoic acid derivatives labeled at C-2.Metal ions seem to play an important role in the relative rates of nucleophilic attack at the α- and β-carbon atoms of 2.Compound 3 was converted to S-tert-butyl 3-acetoxythiobutanoate-2-d (1) with virtually no H-D exchange; the mixed anhydride method proved more effective than the DCC method for the thioester synthesis.
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Lemoigne,Roukhelman
, (1940)
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Protic acid-catalyzed polymerization of β-lactones for the synthesis of chiral polyesters
Jaipuri, Firoz A.,Bower, Brian D.,Pohl, Nicola L.
, p. 3249 - 3252 (2003)
Chiral poly(β-hydroxybutyrate) was prepared with retention of configuration from (R)-β-butyrolactone by ring-opening polymerization catalyzed by triflic acid in an aprotic solvent. At higher temperatures, triflic acid could also be used to depolymerize ch
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MacMillan,J.,Simpson,T.J.
, p. 1487 - 1493 (1973)
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Lemoigne,Girard
, (1944)
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Novel antitumour metabolites produced by a fungal strain from a sea hare
Numata, Atsushi,Iritani, Masashi,Yamada, Takeshi,Minoura, Katsuhiko,Matsumura, Eiko,Yamori, Takao,Tsuruo, Takashi
, p. 8215 - 8218 (1997)
Pericosines A (1) and B (2), and macrosphelides E - H (3 - 6) have been isolated, along with known macrosphelide C (7), from a strain of Periconia byssoides originally separated from the sea hare Aplysia kurodai, and their structures have been established on the basis of spectral analyses. Compounds 1 and 2 exhibited significant inhibitory activity in vitro against tumour cells, and the former also showed significant in vivo tumour-inhibitory activity.
Three new bioactive natural products from the fungus Talaromyces assiutensis JTY2
Cai, Jin,Chen, Guang-Ying,Liao, Qi-Ying,Liao, Shan,Meng, Bo-Zhen,Tang, Min-Min,Yang, Xing,Zhou, Xue-Ming
, (2020)
A novel cyclopentenone derivative, talarocyclopenta A (1), a new phenolicethers derivative, talarocyclopenta B (2) and a new itaconic acid derivative, talarocyclopenta C (3) together with four known itaconic acid derivatives (4–7) were isolated from the Talaromyces assiutensis JTY2. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. Among them, talarocyclopent (1) is the first represent an unusual type of cyclopentenone derivative, possessing a cyclopentenone unit, a 2-butanone unit and a 3-hydroxybutyric acid unit. All isolated compounds were evaluated for their anti-inflammatory and antibacterial activities. Compounds 1–4 showed inhibitory activities against the nitric oxide (NO) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells in vitro. Compound 2 showed broad spectrum antibacterial against six terrestrial pathogenic bacteria.
Stereochemical Consequences of Vinylpyruvate Hydratase-Catalyzed Reactions
Johnson, William H.,Stack, Tyler M. M.,Taylor, Stephanie M.,Burks, Elizabeth A.,Whitman, Christian P.
, p. 4055 - 4064 (2016)
A stereochemical analysis has been carried out on two vinylpyruvate hydratases (VPH), which convert 2-hydroxy-2,4-pentadienoate to 2-keto-4S-hydroxypentanoate in meta-fission pathways. Bacterial strains with this pathway can use aromatic compounds as sole sources of energy and carbon. The analysis was carried out using the 5-methyl and 5-chloro derivatives of 2-hydroxy-2,4-pentadienoate with the enzymes from Pseudomonas putida mt-2 (Pp) and Leptothrix cholodnii SP-6 (Lc). In both organisms, VPH is in a complex with the preceding enzyme in the pathway, 4-oxalocrotonate decarboxylase (4-OD). In D2O, a deuteron is incorporated stereospecifically at the C-3 and C-5 positions of product by both Pp and Lc enzymes. Accordingly, the complexes generate (3S,5S)-3,5-[di-D]-2-keto-4S-hydroxyhexanoate and (3S,5R)-3,5-[di-D]-2-keto-4R-hydroxy-5-chloropentanoate (4R and 5R due to a priority numbering change). The substitution at C-5 (CH3 or Cl) or the source of the enzyme (Pp or Lc) does not change the stereochemical outcome. One mechanism that can account for the results is the ketonization of the 5-substituted dienol to the α,β-unsaturated ketone (placing a deuteron at C-5 in D2O), followed by the conjugate addition of water (placing a deuteron at C-3). The stereochemical outcome for VPH (from Pp and Lc) is the same as that reported for a related enzyme, 2-oxo-hept-4-ene-1,7-dioate hydratase, from Escherichia coli C. The combined observations suggest similar mechanisms for these three enzymes that could possibly be common to this group of enzymes.
Solvent effects on the enthalpy and entropy of activation for the hydrolysis of β-lactones
Manso, Jose A.,Perez-Prior, M. Teresa,Del Pilar Garcia-Santos, Maria,Calle, Emilio,Casado, Julio
, p. 451 - 457 (2008)
The hydrolysis of β-propiolactone and β-butyrolactone in binary water∈+∈dioxane mixtures was investigated by kinetic studies. The following conclusions were reached: First, β-propiolactone is more reactive than β-butyrolactone across the range of water∈+∈dioxane compositions. This observation was rationalized in terms of the electric charge flow caused by the β-butyrolactone's methyl substituent. Second, hydrolysis of these lactones is essentially enthalpy controlled. Third, an increase in the dioxane percentage, which relaxes the intermolecular hydrogen bonds in the ordered structure of water, reduces the enthalpy of activation ΔH # and simultaneously increases the entropy of activation ΔS #(absolute value) for solvent compositions up to 60% dioxane. Fourth, plotting ΔH #/ΔS # against the solvent composition yields an N-shaped curve. This results is a consequence of the quadratic and cubic terms appearing in the expressions of ΔH # and ΔS # as functions of the solvent media composition. Fifth, an ABC classification was set up to characterize the behavior of ΔH #/ΔS # for the solvolysis of these lactones.
PANTETHEINE DERIVATIVES AND USES THEREOF
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Paragraph 2121, (2020/06/19)
The present disclosure relates to compounds of Formula (I), (II), or (II'): (I), (II), (II'), and pharmaceutically acceptable salts or solvates thereof. The present disclosure also relates to pharmaceutical compositions comprising the compounds and therapeutic and diagnostic uses of the compounds and pharmaceutical compositions.
Nitrogen-doped cobalt nanocatalysts for carbonylation of propylene oxide
Chen, Lin,He, Lin,Xia, Chungu,Yang, Bingxiao,Zeng, Bo,Zhu, Gangli
, (2020/07/16)
Nitrogen-doped cobalt nanoparticles loaded on porous supports were developed for ring-opening carbonylation of propylene oxide. The catalysts were prepared by simply pyrolysis of Co(OAc)2/phenanthroline and supports. As proved by XPS combined with XRD and TEM characterizations, a higher amount of available Co-N sites were responsible for promoting the carbonylative activity. The selectivity of carbonylated products reached 93 percent, which is comparable to previously reported cobalt carbonyl catalysts. The novel type of carbonylative catalyst also could be reused and revealed fine stability due to the continuous generation of active [Co(CO)4]? species during reaction.
