- Cyanide as a primordial reductant enables a protometabolic reductive glyoxylate pathway
-
Investigation of prebiotic metabolic pathways is predominantly based on abiotically replicating the reductive citric acid cycle. While attractive from a parsimony point of view, attempts using metal/mineral-mediated reductions have produced complex mixtures with inefficient and uncontrolled reactions. Here we show that cyanide acts as a mild and efficient reducing agent mediating abiotic transformations of tricarboxylic acid intermediates and derivatives. The hydrolysis of the cyanide adducts followed by their decarboxylation enables the reduction of oxaloacetate to malate and of fumarate to succinate, whereas pyruvate and α-ketoglutarate themselves are not reduced. In the presence of glyoxylate, malonate and malononitrile, alternative pathways emerge that bypass the challenging reductive carboxylation steps to produce metabolic intermediates and compounds found in meteorites. These results suggest a simpler prebiotic forerunner of today’s metabolism, involving a reductive glyoxylate pathway without oxaloacetate and α-ketoglutarate—implying that the extant metabolic reductive carboxylation chemistries are an evolutionary invention mediated by complex metalloproteins. [Figure not available: see fulltext.].
- Krishnamurthy, Ramanarayanan,Pulletikurti, Sunil,Yadav, Mahipal,Yerabolu, Jayasudhan R.
-
p. 170 - 178
(2022/02/11)
-
- Selective defunctionalization of citric acid to tricarballylic acid as a precursor for the production of high-value plasticizers
-
Strong concerns about the toxicity and endocrine disrupting properties of widespread phthalate plasticizers stimulate the demand for safe and preferably biobased alternatives. Citric acid forms in this respect an excellent and abundant platform chemical for the production of valuable plasticizers. Here, we report a new and direct synthesis route for propane-1,2,3-tricarboxylic acid (PTA) from citric acid via a sequential one pot dehydration-hydrogenation process. This saturated triacid can serve as a basis for the production of tricarballylate esters via esterification, which have been shown to possess excellent plasticizing properties in vinyl resins. In the presence of a solid acid H-Beta zeolite and Pd/C hydrogenation catalyst, yields up to 85% of PTA were obtained under mild reaction conditions and in water as a green solvent. Partial dealumination of the H-Beta zeolite by citric acid could be counteracted by reincorporating aluminium into the framework of the recycled H-Beta zeolite through realumination, regenerating a significant fraction of the initial activity of the catalytic system. The success of the realumination procedure was verified via MAS NMR spectroscopy.
- De Vos, Dirk E.,Krajnc, Andra?,Mali, Gregor,Stuyck, Wouter,Verduyckt, Jasper
-
supporting information
p. 7812 - 7822
(2020/11/30)
-
- Direct and Selective Synthesis of Adipic and Other Dicarboxylic Acids by Palladium-Catalyzed Carbonylation of Allylic Alcohols
-
A general and direct synthesis of dicarboxylic acids including industrially important adipic acid by palladium-catalyzed dicarbonylation of allylic alcohol is reported. Specifically, the combination of PdCl2 and a bisphosphine ligand (HeMaRaphos) promotes two different carbonylation reactions with high activity and excellent selectivity.
- Beller, Matthias,Ge, Yao,Huang, Weiheng,Jackstell, Ralf,Liu, Jiawang,Neumann, Helfried,Yang, Ji
-
supporting information
p. 20394 - 20398
(2020/09/21)
-
- Flame-retardant aconitic acid-derived small molecules
-
A flame-retardant aconitic acid-derived small molecule, a process for forming a flame-retardant polymer, and an article of manufacture comprising a material that contains a flame-retardant aconitic acid-derived small molecule are disclosed. The flame-retardant aconitic acid-derived small molecule can be synthesized from aconitic acid obtained from a bio-based source, and can have at least one phosphoryl or phosphonyl moiety with phenyl, allyl, or thioether substituents. The process for forming the flame-retardant polymer can include reacting an aconitic acid derivative with a flame-retardant phosphorus-based molecule to form a flame-retardant aconitic acid-derived small molecule, and combining the flame-retardant aconitic acid-derived small molecule with a polymer. The material in the article of manufacture can be a resin, adhesive, polymer, etc.
- -
-
Page/Page column 2
(2019/05/18)
-
- METHOD FOR THE PRODUCTION OF METHYLSUCCINIC ACID AND THE ANHYDRIDE THEREOF FROM CITRIC ACID
-
A process for the preparation of methylsuccinic acid in any form, including its salts, its mono- and diester derivatives and the anhydride thereof, which comprises reacting citric acid or a derivative thereof in decarboxylation conditions, said process comprising (i) reacting citric acid or mono- and diester derivatives thereof in a non- aqueous solvent, specifically excluding alcohols, on a metallic catalyst at a temperature between 50 to 400°C and under a partial hydrogen pressure from 0.1 to 50 bar or (ii) reacting citric acid or any salt thereof or mono-, di- and triester derivatives thereof on a metallic catalyst in solvents comprising at least 5% water, at a temperature of from 50 to 400°C under a hydrogen partial pressure from 0.1 to 400 bar
- -
-
Page/Page column 13-15
(2018/04/21)
-
- Highly selective one-step dehydration, decarboxylation and hydrogenation of citric acid to methylsuccinic acid
-
The one-step dehydration, decarboxylation and hydrogenation of the bio-based and widely available citric acid is presented. This reaction sequence yields methylsuccinic acid with yields of up to 89%. Optimal balances between the reaction rates of the different steps were found by varying the hydrogenation catalyst and the reaction parameters (H2 pressure, pH, temperature, time and catalyst-to-substrate ratio).
- Verduyckt, Jasper,De Vos, Dirk E.
-
p. 2616 - 2620
(2017/04/06)
-
- Reaction of 3-dehydroshikimic acid with molecular oxygen and hydrogen peroxide: Products, mechanism, and associated antioxidant activity
-
In the presence of molecular oxygen or hydrogen peroxide, inorganic phosphate catalyzes the conversion of 3-dehydroshikimic acid (DHS) into gallic acid. Other products formed in the reaction of DHS with oxygen include protocatechuic acid, tricarballylic acid, and pyrogallol. With hydrogen peroxide as oxidant, pyrogallol formation is not observed, and smaller amounts of tricarballylic acid are produced. Evidence favoring a mechanism involving phosphate-catalyzed tautomerization of DHS to a reactive enediol intermediate follows from the successful isolation of dihydrogallic acid when oxidant is excluded from phosphate-buffered solutions of DHS. The reductone-like solution chemistry of DHS and the radical quenching reactivity of the phenolics formed from DHS prompted an appraisal of DHS antioxidant activity. Based on two different analyses, DHS was discovered to possess significant antioxidant activity relative to α-tocopherol, gallic acid, propyl gallate, and tert-butylhydroquinone.
- Richman, Jack E.,Chang, Yu-Chen,Kambourakis, Spiros,Draths,Almy, Erick,Snell, Kristi D.,Strasburg, Gale M.,Frost
-
p. 11587 - 11591
(2007/10/03)
-
- Optically active phenoxypropionic esters
-
Optically active compounds of the formula I STR1 where R is C1 -C12 -alkyl or -perfluoroalkyl in which one or two non-adjacent CH2 or CF2 groups can also be replaced by --O-- and/or --CO-- and/or --CO--O-- and/or --CH=CH-- and/or --CH-halogen-- and/or --CHCN-- and/or --0--CO--CH-halogen-- and/or --O--CO--CHCN--, or is C1 -C12 -alkyl which can have a terminal chemically reactive group and in which a CH2 group can be replaced by --O--, A1 and A2 are each, independently of one another, 1,4-phenylene which is unsubstituted or substituted by one or two F and/or Cl and/or Br atoms and/or CH3 groups and/or CN groups and in which one or two CH groups can also be replaced by N, 1,4-cyclohexylene in which one or two non-adjacent CH2 groups can also be replaced by --O-- and/or --S--, 1,4-piperidinediyl, 1,4-bicyclo[2.2.2]octylene, 2,6-naphthalenediyl, decahydro-2,6-naphthalenediyl or 1,2,3,4-tetrahydro-2,6-naphthalenediyl, A3 is unsubstituted or substituted phenyl, Z is --CO--O--, --O--CO--, --CH2 CH2 --, --OCH2 --, --CH2 O--, --C C-- or a single bond and m is 0, 1, 2 or 3.
- -
-
-
- REACTION OF CHLORINE-SUBSTITUTED NITROETHYLENES WITH MALONIC ESTER
-
The direction of the reaction of 2-chloro-, 1,2-dichloro-, and 2,2-dichloronitroethylenes with malonic ester and the structure of the products depend on the structure of the initial chloronitroalkenes.Thus, from 2-chloro-1-nitroethylene a salt of substituted nitropropene was obtained; during an attempt at its isolation it was converted into a dimer- a derivative of cyclobutane.A derivative of nitrocyclopropane was obtained from 1,2-dichloro-1-nitroethylene, and a compound with an open chain was obtained from the isomeric 2,2-dichloro-1-nitroethylene.The structures of the obtained compounds were established by certain chemical transformations and on the basis of their IR, UV, and PMR spectra.
- Buevich, V. A.,Deiko, L. I.,Volynskii, V. E.
-
p. 2055 - 2058
(2007/10/02)
-
