53538-53-7

Upstream product

• 141-82-2 malonic acid 
• 123-38-6 propionaldehyde 
• 94953-76-1 lithium α-lithioacetate 
• 4949-44-4 ethyl propanoylacetate 
• 89448-49-7 3,5-O-Benzylidene-2-O-<(methylthio)thiocarbonyl>-D-ribonic Acid γ-Lactone 
• 546-68-9 titanium(IV) isopropylate 
• 124-38-9 carbon dioxide 
• 15687-27-1 ibuprofen 
• 42558-50-9 methyl (3R)-3-hydroxypentanoate 
• 119301-96-1 D-3-acetoxy-valeric acid methyl ester 
• 26432-16-6 (3R)-acetoxy-pentanedioic acid monomethyl ester 
• 79199-73-8 3-acetoxy-pentanedioic acid monomethyl ester 
• 201555-10-4 C₉H₁₇NO₃S 
• 64074-05-1 2,2-dimethyl-5-propanoyl-1,3-dioxan-4,6-dione 

Downstream Products

• 918294-92-5 (3R)-3-hydroxy-N-[(1S,2R)-2-hydroxy-3-[[(4-methoxyphenyl)sulfonyl]pentylamino]-1-(phenylmethyl)propyl]-pentanamide 
• 918294-93-6 (3R)-N-[(1S,2R)-3-[(6-benzothiazolylsulfonyl)pentylamino]-2-hydroxy-1-(phenylmethyl)propyl]-3-hydroxy-pentanamide 
• 918294-82-3 (3R)-3-hydroxy-N-[(1S,2R)-2-hydroxy-3-[[(4-methoxyphenyl)sulfonyl](2-methylpropyl)amino]-1-(phenylmethyl)propyl]-pentamide 
• 918294-83-4 (3R)-N-[(1S,2R)-3-[(6-benzothiazolylsulfonyl)(2-methylpropyl)amino]-2-hydroxy-1-(phenylmethyl)propyl]-3-hydroxy-pentanamide 
• 918295-03-1 (3R)-N-[(1S,2R)-3-[(6-benzothiazolylsulfonyl)[(2S)-2-methylbutyl]amino]-2-hydroxy-1-(phenylmethyl)propyl]-3-hydroxy-pentanamide 
• 178246-92-9 (R)-3-((R)-3-Benzyloxy-butyryloxy)-pentanoic acid (R)-1-benzyloxycarbonylmethyl-propyl ester 
• 178246-91-8 (R)-3-((R)-3-Benzyloxy-butyryloxy)-pentanoic acid (R)-2-benzyloxycarbonyl-1-methyl-ethyl ester 
• 178246-88-3 (R)-3-(tert-Butyl-dimethyl-silanyloxy)-pentanoic acid (R)-1-benzyloxycarbonylmethyl-propyl ester 
• 179422-30-1 (R)-3-(tert-Butyl-dimethyl-silanyloxy)-pentanoic acid (R)-2-benzyloxycarbonyl-1-methyl-ethyl ester 
• 178246-90-7 (R)-3-Hydroxy-pentanoic acid (R)-1-benzyloxycarbonylmethyl-propyl ester 
• 178246-89-4 (R)-3-Hydroxy-pentanoic acid (R)-2-benzyloxycarbonyl-1-methyl-ethyl ester 
• 129619-37-0 (R,R)-octane-3,6-diol 
• 42558-50-9 methyl (3R)-3-hydroxypentanoate 

Relevant academic research and scientific papers

General chemoenzymatic route to two-stereocenter triketides employing assembly line ketoreductases

Modular polyketide synthases (PKSs) are enzymatic assembly lines that fuse carbon fragments into complex chiral products. Here, their synthetic logic is employed to chemoenzymatically generate two-stereocenter triketides. Each of the four stereoisomers was constructed in a stereocontrolled manner using C-acylation and two PKS ketoreductases possessing opposite stereoselectivities.

A study of the reaction of n-BuLi with Ti(Oi-Pr)4 as a method to generate titanacyclopropane and titanacyclopropene species

The use of the combination of reagents Ti(Oi-Pr)4/n-BuLi, introduced by the group of J.J. Eisch in 2001, has only found a few applications so far, with sometimes conflicting observations. This article describes a study aimed at clarifying the nature, the stability and the reactivity of the active organometallic species involved. Reactions with CO2 and other trapping reagents reveal that it is generated within a few minutes at 0 C in THF, where it can be considered to be stable for 30 min. Most of our results are consistent with the expected titanacyclopropane nature of this reagent but some observations suggest that the chemistry at play may be more complicated.

Photolysis and photocatalysis of ibuprofen in aqueous medium: Characterization of by-products via liquid chromatography coupled to high-resolution mass spectrometry and assessment of their toxicities against Artemia Salina

The degradation of the pharmaceutical compound ibuprofen (IBP) in aqueous solution induced by direct photolysis (UV-A and UV-C radiation) and photocatalysis (TiO2/UV-A and TiO2/UV-C systems) was evaluated. Initially, we observed that whereas photocatalysis (both systems) and direct photolysis with UV-C radiation were able to cause an almost complete removal of IBP, the mineralization rates achieved for all the photodegradation processes were much smaller (the highest value being obtained for the TiO 2/UV-C system: 37.7%), even after an exposure time as long as 120 min. Chemical structures for the by-products formed under these oxidative conditions (11 of them were detected) were proposed based on the data from liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) analyses. Taking into account these results, an unprecedented route for the photodegradation of IBP could thus be proposed. Moreover, a fortunate result was achieved herein: tests against Artemia salina showed that the degradation products had no higher ecotoxicities than IBP, which possibly indicates that the photocatalytic (TiO2/UV-A and TiO2/UV-C systems) and photolytic (UV-C radiation) processes can be conveniently employed to deplete IBP in aqueous media. Copyright

PHA E and PHA C components of poly(hydroxy fatty acid) synthase from thiocapsa pfennigii

PCT No. PCT/DE95/01279 Sec. 371 Date Jul. 3, 1997 Sec. 102(e) Date Jul. 3, 1997 PCT Filed Sep. 15, 1995 PCT Pub. No. WO96/08566 PCT Pub. Date Mar. 21, 1996The present invention relates to a process for the production of poly (hydroxy fatty acids) as well as recombinant bacterial strains for carrying out the process. In addition, new poly(hydroxy fatty acids) and new substrates for the production of conventional and new poly(hydroxy fatty acids) are described. Moreover, the invention also relates to a DNA fragment, which codes for a PhaE and a PhaC component of the poly(hydroxy fatty acid) synthase from Thiocapsa pfennigii, as well as the corresponding poly (hydroxy fatty acid) synthase protein.

Preparation and structure of oligolides from (R)-3-hydroxypentanoic acid and comparison with the hydroxybutanoic-acid derivatives: A small change with large consequences

Cyclic oligomers of (R)-3-hydroxyvaleric acid (3-HV) are prepared from the monomer by three different methods, giving various ratios of the oligomers. The macrocycles containing three to twelve 3-HV units (12- to 48-membered rings) are isolated in pure form by chromatography. The triolide 3 can be separated by distillation and isolated on large scale. Biopol, the copolymer of (R)-3-hydroxybutanoic acid (3-HB) and (R)-3-hydroxyvaleric acid (3-HV), is degraded to mixtures of Me- and Et-substituted triolides ('mixolides') with high crystallization tendency. The X-ray crystal structures of the tetrolide 4, pentolide 5, hexolide 6, heptolide 7, and of two 'mixolides' (with inclusions of solvent) have been determined and are compared with those of the corresponding 3-HB derivatives reported previously. From the structural data, a 31 and a 21 helix of 3-HV can be modelled, and the latter one compared with helix structures of P(3-HB) and P(3-HV) derived from stretch-fibre X-ray scattering. Crystals of a water-containing NaSCN complex of the triethyl triolide 3 were obtained in good quality for X-ray analysis. The structure contains an interesting array of C=O and H2O O-atoms around the Na+ ions along a channel-type tube (a-axis of the crystal) which may be relevant to the role of P(3-HB) and P(3-HV) as components of cellular ion channels.

Biodegradable optically active polymers and intermediate oligomers thereof, and process for producing them

An optically active oligomer obtained by polycondensation of an (R)-3-hydroxyalkanoic acid alkyl ester and a diol, a diamine and/or an amino alcohol may be copolymerized with monomer selected from diisocyanic acid esters, dicarboxylic acid derivatives, and dichlorosilanes to give an optically active polymer. The functional thermoplastic polymers so produced (polyesters, polyetherpolyesters, polyester-polyurethanes and polyester-polyether-polyurethanes) are biodegradable and hydrolyzable, and lend themselves to industrial production.

New chiral phospholanes; synthesis, characterization, and use in asymmetric hydrogenation reactions

We describe the practical synthesis of enantiomerically pure trans-2,5-disubstituted-1-phenylphospholanes which are then employed in the preparation of a new series of C2-symmetric bis- and C3-symmetric tris(phospholane) ligands. A versatile three-step route to the important chiral 1,4-diol intermediates, used in the phosphine syntheses, is outlined. Rhodium complexes bearing the new phosphine ligands were prepared and shown to act as efficient catalyst precursors for the enantioselective hydrogenation of various unsaturated substrates.

Asymmetric Reduction of Aliphatic Short- to Long-Chain β-Keto Acids by Use of Fermenting Bakers' Yeast

Eleven β-keto acids, ranging from 3-oxobutanoic to 3-oxooctanoic acids, were reduced with fermenting bakers' yeast to the corresponding optically active β-hydroxy acids, which were isolated as the methyl esters.In all cases, the (R)-hydroxy acids were obtained in >/=98percent ee, except for 3-oxobutanoic acid, which afforded the (S)-hydroxy acid in 86percent ee.Inhibition of fermentation was observed for 3-oxoundecanoic to 3-oxotetradecanoic acids, leading to no reduction.Lowering of the substrate concentration was found to be appreciably effective in avoiding inhibition.

104. Bromination of Cyclic Acetals from α-Amino Acids and α- or β-Hydroxy Acids with N-Bromosuccinimide

The preparation of novel electrophylic building blocks for the synthesis of enantiomerically pure compounds (EPC) is described.Thus, the 2-(tert-butyl)dioxolanones, -oxazolidinones, -imidazolidinones, and -dioxanones obtained by acetalization of pivalalde

CHIRAL ACETATE ENOLATE EQUIVALENT FOR THE SYNTHESIS OF β-HYDROXY ACIDS AND ESTERS: X-RAY CRYSTAL STRUCTURE OF RR,SS-5-C5H5)Fe(CO)(PPh3)(COCH2CH(OH)CH2CH3)>

The aluminium anolate derived from the iron acetyl complex 5-C5H5)Fe(CO)(PPh3)COCH3>, in contrast to the lithium enolate, undergoes highly strereoselective aldol reactions with aldehydes to generate RR,SS-β-hydroxyacyl complexes which on decomlexation liberate β-hydroxy acids or esters.Determination of the molecular structure of RR,SS-5-C5H5)Fe(CO)(PPh3)(COCH2CH(OH)CH2CH3> allowed assignment of the relative configuration of the new chiral centre.