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.
Ueber die Depolymerisierung von Poly-(R)-3-hydroxy-buttersaeureester (PHB)
Seebach, Dieter,Zueger, Max
, p. 495 - 503 (1982)
On the Depolimerization of Poly-(R)-3-hydroxy-butanoate (PHB): From cell-free PHB or from dried cells of Alcaligens eutrophus H 16, which had been grown in an aqueous fructose solution, enantiomerically pure methyl, ethyl, butyl or β-methoxyethyl (R)-3-hydroxy-butanoates are obtained in yields ranging from 75-90percent (0.1 to 70 g scale).The depolimerization is achieved by heating the PHB-containing materials to temperatures of 80-100 deg C in the corresponding alcohol with or without the cosolvent dichloroethane in the presence of either sulfuric acid or tetraethoxytitanium catalyst.Since (S)-3-hydroxy-butanoates are also readily obtained (by yeast reduction of aceto-acetates), starting materials derived from 3-hydroxy-butyric acid now belong to the especially useful group of synthetic building blocks which are available in both enantiomeric forms.
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
Stereochemical and isotopic labeling studies of 4-oxalocrotonate decarboxylase and vinylpyruvate hydratase: Analysis and mechanistic implications
Lian, Huiling,Whitman, Christian P.
, p. 10403 - 10411 (1994)
Stereochemical and isotopic labeling studies of 4-oxalocrotonate decarboxylase (EC 4.1.1.-; 4-OD) and vinylpyruvate hydratase (EC 4.2.1.-; VPH) from Pseudomonas putida mt-2 have been completed. The two enzymes, reportedly a complex, catalyze successive reactions in the catechol meta-fission pathway and convert 2-oxo-3-hexenedioate (1) to 2-oxo-4-hydroxypentanoate (2) using either manganese or magnesium as a cofactor. 2-Oxo-4-pentenoate (3) and 2-hydroxy-2,4-pentadienoate (4) have been detected by UV and 1H NMR spectroscopy in the 4-OD-catalyzed decarboxylation of 1. Incubation of 4 with 4-OD in 2H2O resulted in its highly stereoselective ketonization to afford (35)-[3-2H]3. A reasonable hypothesis to explain these observations is that 4-OD catalyzes the decarboxylation of 1 to 3 through the intermediacy of the dienol 4. It was further shown that 4-OD converts (5S)-[S-2H]1 to 4E-[5-2H]4 in 2H2O. These Stereochemical results coupled with the previously established S configuration of [5-2H]1 indicate that the loss of carbon dioxide and the incorporation of a deuteron occur on the same side of the dienol intermediate. The product of the 4-OD/VPH complex was also isolated and identified unequivocally as (4S)-2. Finally, it was determined by an 18O labeling experiment that the hydroxyl group at C-4 of 2 is derived from solvent water and that it is unlikely that either 4-OD or VPH utilizes a Schiff base intermediate.
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.
Hydrolysis and retro-aldol cleavage of ethyl threo-2-(1-adamantyl)-3- hydroxybutyrate: Competing reactions
Ganguly, Bishwajit,Kesharwani, Manoj K.,Matkovic, Marija,Basaric, Nikola,Singh, Ajeet,Mlinaric-Majerski, Kata
, p. 578 - 587 (2011)
The hydrolysis of ethyl threo-2-(1-adamantyl)-3-hydroxybutyrate (1) and the parent ester ethyl 3-hydroxybutyrate (4) has been studied experimentally and computationally. In the hydrolysis of threo-ester 1 with 2M NaOH, predominantly retro-aldol product was observed, whereas the hydrolyzed product was present in a minor amount. When the reaction is carried out under the same conditions with the parent ester ethyl 3-hydroxybutyrate (4), hydrolyzed product is exclusively observed. The competitive pathways, namely hydrolysis and the retro-aldol reaction for 1 and 4 were investigated using DFT calculations in the both gas and solvent phase. The calculated results in the solvent phase at B3LYP/6-31+G* level revealed that the formation of retro-aldol products is kinetically preferred over the hydrolysis of threo-ester 1 in the presence of a base. However, the parent ester 4 showed that the retro-aldol process is less favored than the hydrolysis process under similar conditions. The steric effect imposed by the bulky adamantyl group to enhance the activation barriers for the hydrolysis of the ethyl threo-2-(1-adamantyl)-3-hydroxybutyrate (1) was further supported by the calculations performed with tert-butyl group at the α-carbon atom of ethyl 3-hydroxybutyrate (7).
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.
SYNTHESIS OF 3-HYDROXYBUTYRYL 3-HYDROXYBUTYRATE AND RELATED COMPOUNDS
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Paragraph 0308; 0320-0324, (2021/04/02)
In various embodiments methods of preparing hydroxybutyryl 3-hydroxybutyrate and related compounds are provided along with methods of use thereof.
