ChemInform Abstract: Enzymes in Organic Synthesis. Part 15. Short Enzymatic Synthesis of L‐Fucose Analogues.

Abstract

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Enzymes for the biocatalytic production of rare sugars

“…These enzymes also tolerate other modifications at centers higher than C3 and can use epimeric or functionalized sugars as substrates. Examples hereof are terminusmodified fuculose analogues for L-fucose isomerase [21]. Other related enzymes, including xylose (glucose) isomerase, have also been shown to accept deoxygenated and/or substituted sugars [20,31,90].…”

“…Two isomerases that prefer deoxy-sugars as their substrates are L-fucose isomerase [21,47] and L-rhamnose isomerase [57,58]. These enzymes also tolerate other modifications at centers higher than C3 and can use epimeric or functionalized sugars as substrates.…”

Synthesis of short-chain hydroxyaldehydes and their 2,4-dinitrophenylhydrazone derivatives, and separation of their isomers by high-performance liquid chromatography

“…The product was isolated by evaporation directly from the crude at rt into a cold trap kept at −196 • C and subsequently stored at −80 • C. The product is a colorless oil at −20 • C (712 mg, 8.27 mmol, 36%). Its NMR shows signals of both, keto and enol-form in a ratio of 1:6 at 20 • C in chloroform-d. 1 Following the method reported in the literature [13], 1,1dimethoxy-2-methylpropan-2-ol (537 mg, 4.00 mmol) was dissolved in deionized water (40 mL) and acidic ion exchange resin (Merck Ion exchanger type I) was added. The suspension was stirred at rt for 5 h, then the resin was filtered off.…”

“…Enlarged representations of both graph showing the lower concentration regime are to be found in the SI. 1: Formaldehyde-DNPH (y = 168.56x; R 2 = 0.9997), 2: Acetaldehyde-DNPH (y = 126.58x; R 2 = 1), 3: Acrolein-DNPH (y = 108.33x; R 2 = 1), 4: Acetone-DNPH (y = 93.992x; R 2 = 0.9997), 5: Crotonaldehyde-DNPH (y = 89.841; R 2 = 0.9999), 6: Butyraldehyde-DNPH (y = 75.983x; R 2 = 1), 7: Isobutyraldehyde-DNPH (y = 76.239x; R 2 = 1), 8: 3-Hydroxybutyraldehyde-DNPH (y = 96.108x; R 2 = 1), 9: 2-Hydroxyisobutyraldehyde-DNPH (y = 69.131x; R 2 = 1), 10: Acetoacetaldehyde-DNPH (pyrazole) (y = 22.624x; R 2 = 0.9999) 13. C NMR (101 MHz, Chloroform-d) ␦ 196.9 (C O (enol)), 175.6 (HOC C (enol)), 102.5 (HOC C (enol)), 26.4 (CH 3 (enol)); Signals of the keto-tautomer are omitted because of low signal-to-noise ratio.2.3.7.…”