The Trimerization of Glycolonitrile

Lake, D. B.; Londergan, Thomas E.

doi:10.1021/jo01377a018

Cited by 13 publications

(11 citation statements)

References 2 publications

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“…However, this route is also overall energetically unfavorable and suffers from the same issues described by 10 → 33 → 34 → 35. Based on our map, we conclude that while glyoxal is accessible, most likely via 26, its formation is less energetically favorable than other competing reactions and is less likely to be observed Lake and Londergan reported its presence using dimedone, 8 while Arrhenius and co-workers did not detect its presence. 5 We now return to the ring-opening reactions on the right side of Figure 3.…”

Section: ■ Computational Methodsmentioning

confidence: 74%

“…Although Lake and Londergan mentioned the triazine, they favored the pyridine as the aromatic trimer product. 8 There are thermodynamic reasons for this: the pyridine is more stable than the triazine. Our calculated route to the pyridine also requires traversing the reaction 1 + 39 → 66 but, in addition, requires going through less stable tautomers 70 and 71 that have an imidic acid moiety rather than the more stable amide.…”

Section: ■ Computational Methodsmentioning

confidence: 99%

“…A 1954 paper by Lake and Londergan proposed a pyridine, rather than a triazine, as the crystalline material formed in aqueous NaOH at pH 8 and 0 °C. 8 They also proposed that subsequent hydrolytic degradation led to glycolamide and glycoliminohydrin (the salt of glycolamidine and glycolic acid), and in addition, glyoxal was identified (using dimedone) as a further degradation product from a polymeric side product of the reaction. Arrhenius et al used similar reaction conditions (aqueous KOH at pH 8.2 and 0−3 °C) in their 1994 paper, 5 identifying the crystalline material as the (dimer) oxazole rather than the (trimer) pyridine.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Experimentally, what is known about the oligomerization of glycolonitrile? A 1954 paper by Lake and Londergan proposed a pyridine, rather than a triazine, as the crystalline material formed in aqueous NaOH at pH 8 and 0 °C . They also proposed that subsequent hydrolytic degradation led to glycolamide and glycoliminohydrin (the salt of glycolamidine and glycolic acid), and in addition, glyoxal was identified (using dimedone) as a further degradation product from a polymeric side product of the reaction.…”

Section: Introductionmentioning

confidence: 99%

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Early Steps of Glycolonitrile Oligomerization: A Free-Energy Map

Kua

Paradela

2020

J. Phys. Chem. A

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Building on our previous free-energy map (J. Phys. Chem. A 2018, 122, 6769–6779) examining the reactions of monomeric glycolonitrile, we explore the formation of its dimers and trimers in aqueous solution under neutral conditions. While 5-membered rings are kinetically favored, open-chain oligomers with ester or amide linkages are thermodynamically favored. Accessing the 5-membered rings also provides a potential route to glyoxal that bypasses preforming glycolamide, the thermodynamic sink for monomers. However, finding a kinetically accessible route to glycine starting from glycolonitrile in the absence of added ammonia at room temperature proved challenging; the best case involved an intramolecular nucleophilic substitution reaction in a dimer containing neighboring imine and amide groups. Our free-energy map also examines routes to experimentally proposed moieties, explaining why some are observed in low yield or not at all.

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Section: ■ Computational Methodsmentioning

confidence: 74%

Section: ■ Computational Methodsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Early Steps of Glycolonitrile Oligomerization: A Free-Energy Map

Kua

Paradela

2020

J. Phys. Chem. A

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“…[17][18][19][20][21] Cell paste isolated from fermentation was frozen at À80 8C without pre-treatment with glycerol or DMSO, and thawed prior to use in reactions or for immobilization in carrageenan. Wet cell weights of microbial catalysts employed in reactions or assays were ob-tained from cell pellets prepared by centrifugation of fermentation broth or cell suspensions in buffer.…”

Section: Experimental Section Materials and Methodsmentioning

confidence: 99%

Chemoenzymatic Synthesis of Glycolic Acid

et al. 2007

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A chemoenzymatic process for the production of high-purity glycolic acid has been demonstrated, starting with the reaction of formaldehyde and hydrogen cyanide to produce glycolonitrile in > 99 % yield and purity. The resulting aqueous glycolonitrile was used without further purification in a subsequent biocatalytic conversion of glycolonitrile to ammonium glycolate. A high-activity biocatalyst based on an Acidovorax facilis 72W nitrilase was developed, where protein engineering and optimized protein expression in an E. coli transformant host were used to improve microbial nitrilase specific activity by 33-fold compared to the wild-type strain. A biocatalyst productivity of > 1000 g glycolic acid/g dry cell weight was achieved using a glutaraldehyde/ polyethylenimine cross-linked carrageenan-immobilized E. coli MG1655 transformant expressing the A. facilis 72W nitrilase mutant, where 3.2 M ammonium glycolate was produced in consecutive batch reactions with biocatalyst recycle, or in a continuous stirred-tank reactor. Direct conversion of the unpurified ammonium glycolate product solution to highpurity aqueous glycolic acid was accomplished by fixed-bed ion exchange over a strong acid cation resin.

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