Practical Synthesis of the Fluorogenic Enzyme Substrate 4-Methylumbelliferyl α-l-Idopyranosiduronic Acid

Synlett ◽  
2020 ◽  
Vol 31 (11) ◽  
pp. 1083-1086
Author(s):  
Haixin Ding ◽  
Qiang Xiao ◽  
Jiameng Tian ◽  
Wenliang Ouyang ◽  
Yanling He ◽  
...  
Keyword(s):  
Enzyme Substrate ◽  
Radical Bromination ◽  
Radical Reduction ◽  
Practical Synthesis

A practical and concise synthesis of 4-methylumbelliferyl α-l-idopyranosiduronic acid, a fluorogenic enzyme substrate diagnostic for α-l-iduronidase, was accomplished. It features successive radical bromination and radical reduction of easily accessible methyl 4-methyl­umbelliferyl-2,3,4-tri-O-acetyl-β-d-glucouronate in four steps with 28% overall yield.

scholarly journals Improved synthesis of gastrodin, a bioactive component of a traditional Chinese medicine

2014 ◽  
Vol 79 (10) ◽  
pp. 1205-1212 ◽  
Author(s):  
Yu-Wen Li ◽  
Cui-Li Ma
Keyword(s):  
Chinese Medicine ◽  
Initial Step ◽  
Aqueous Sodium ◽  
Radical Bromination ◽  
Bioactive Component ◽  
Glycosyl Donor ◽  
Practical Synthesis ◽  
Saturated Aqueous Sodium Bicarbonate ◽  
Saturated Aqueous Sodium ◽  
Operational Simplicity

Highly practical synthesis of gastrodin has been developed using penta-O-acetyl-b-D-glucopyranose and p-cresol as glycosyl donor and glycosyl acceptor, respectively, in four steps with 58.1% overall yield. At the initial step, the penta-O-acetyl-b-D-glucopyranose was treated with p-cresol in the presence of BF3.Et2O as catalyst to generate 4-methylphenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyranoside in 76.3% yield. Furthermore, this product was subjected to radical bromination with NBS to provide 4-(bromomethyl) phenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyranoside in 91% yield. Subsequently, reaction of 2,3,4,6-tetra-O-acetyl-b-D-glucopyranoside with a solution of acetone and saturated aqueous sodium bicarbonate led to 4-(hydroxylmethyl) phenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyranoside in 93% yield. Finally, global deprotection of 4-(hydroxylmethyl) phenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyranoside under Zemplen conditions furnished gastrodin in 90% yield. Compared to the previously reported methods, this protocol has advantages of operational simplicity, chromatography-free separation, high overall yield, inexpensive and common reagents as well as less waste pollutants, rendering it an alternative suitable for industrial production.

Cell-Specific Chemical Delivery Using a Selective Nitroreductase–Nitroaryl Pair

2018 ◽  
Author(s):  
Todd D. Gruber ◽  
Chithra Krishnamurthy ◽  
Jonathan B. Grimm ◽  
Michael R. Tadross ◽  
Laura M. Wysocki ◽  
...  
Keyword(s):  
Small Molecules ◽  
Mammalian Cells ◽  
Target Cells ◽  
Specific Chemical ◽  
E Coli ◽  
Enzyme Substrate ◽  
Cell Specificity ◽  
General Chemical ◽  
Increased Activity ◽  
Enzyme Variant

<p>The utility of<b> </b>small molecules to probe or perturb biological systems is limited by the lack of cell-specificity. ‘Masking’ the activity of small molecules using a general chemical modification and ‘unmasking’ it only within target cells could overcome this limitation. To this end, we have developed a selective enzyme–substrate pair consisting of engineered variants of <i>E. coli</i> nitroreductase (NTR) and a 2‑nitro-<i>N</i>-methylimidazolyl (NM) masking group. To discover and optimize this NTR–NM system, we synthesized a series of fluorogenic substrates containing different nitroaromatic masking groups, confirmed their stability in cells, and identified the best substrate for NTR. We then engineered the enzyme for improved activity in mammalian cells, ultimately yielding an enzyme variant (enhanced NTR, or eNTR) that possesses up to 100-fold increased activity over wild-type NTR. These improved NTR enzymes combined with the optimal NM masking group enable rapid, selective unmasking of dyes, indicators, and drugs to genetically defined populations of cells.</p>

The Nature of Degrowth: Theorising the Core of Nature for the Degrowth Movement

2020 ◽  
Author(s):  
Pasi Heikkurinen
Keyword(s):  
Human Nature ◽  
Culturally Sensitive ◽  
Theory And Practice ◽  
The Core ◽  
The Past ◽  
The Future ◽  
Radical Reduction ◽  
Nature Experience ◽  
Matter Energy

This article investigates human–nature relations in the light of the recent call for degrowth, a radical reduction of matter–energy throughput in over-producing and over-consuming cultures. It outlines a culturally sensitive response to a (conceived) paradox where humans embedded in nature experience alienation and estrangement from it. The article finds that if nature has a core, then the experienced distance makes sense. To describe the core of nature, three temporal lenses are employed: the core of nature as ‘the past’, ‘the future’, and ‘the present’. It is proposed that while the degrowth movement should be inclusive of temporal perspectives, the lens of the present should be emphasised to balance out the prevailing romanticism and futurism in the theory and practice of degrowth.

Convenient Synthesis of (Z)-7- and (E)-9-dodecene-1-yl Acetate, Components of Some Lepidoptera Insect Sex Pheromone

2017 ◽  
Vol 68 (1) ◽  
pp. 180-185
Author(s):  
Adriana Maria Andreica ◽  
Lucia Gansca ◽  
Irina Ciotlaus ◽  
Ioan Oprean
Keyword(s):  
Sex Pheromone ◽  
Coupling Reaction ◽  
Coupling Scheme ◽  
Lithium Aluminium Hydride ◽  
Terminal Alkyne ◽  
Mercury Derivative ◽  
Lithium Aluminium ◽  
Convenient Synthesis ◽  
Practical Synthesis ◽  
Insect Sex

Were developed new and practical synthesis of (Z)-7-dodecene-1-yl acetate and (E)-9-dodecene-1-yl acetate. The routes involve, as the key step, the use of the mercury derivative of the terminal-alkyne w-functionalised as intermediate. The synthesis of (Z)-7-dodecene-1-yl acetate was based on a C6+C2=C8 and C8+C4=C12 coupling scheme, starting from 1,6-hexane-diol. The first coupling reaction took place between 1-tert-butoxy-6-bromo-hexane and lithium acetylide-ethylendiamine complex obtaining 1-tert-butoxy-oct-7-yne, which is transformed in di[tert-butoxy-oct-7-yne]mercury. The mercury derivative was directly lithiated and then alkylated with 1-bromobutane obtaining 1-tert-butoxy-dodec-7-yne. After acetylation and reduction with lithium aluminium hydride of 7-dodecyne-1-yl acetate gave (Z)-7-dodecene-1-yl acetate with 96 % purity. The synthesis of (E)-9-dodecene-1-yl acetate was based on a C8+C2=C10 and C10+C2=C12 coupling scheme, starting from 1,8-octane-diol. The first coupling reaction took place between 1-tert-butoxy-8-bromo-octane and lithium acetylide-ethylendiamine complex obtaining 1-tert-butoxy-dec-9-yne, which is transformed in di[tert-butoxy-dec-9-yne]mercury. The mercury derivative was directly lithiated and then alkylated with 1-bromoethane obtaining 1-tert-butoxy-dodec-9-yne. After reduction with lithium aluminium hydride of 1-tert-butoxy-(E)-9-dodecene and acetylation was obtained (E)-9-dodecene-1-yl acetate with 97 % purity.

The role of secondary alcoholic groups of D-galacturonan in its degradation with exo-D-galacturonanase

1980 ◽  
Vol 45 (2) ◽  
pp. 427-434 ◽  
Author(s):  
Kveta Heinrichová ◽  
Rudolf Kohn
Keyword(s):  
Acetyl Derivative ◽  
Competitive Inhibitor ◽  
Hydroxyl Groups ◽  
Pectic Acid ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
The Individual ◽  
Degradation Degree ◽  
Derivatives Of

The effect of exo-D-galacturonanase from carrot on O-acetyl derivatives of pectic acid of variousacetylation degree was studied. Substitution of hydroxyl groups at C(2) and C(3) of D-galactopyranuronic acid units influences the initial rate of degradation, degree of degradation and its maximum rate, the differences being found also in the time of limit degradations of the individual O-acetyl derivatives. Value of the apparent Michaelis constant increases with increase of substitution and value of Vmax changes. O-Acetyl derivatives act as a competitive inhibitor of degradation of D-galacturonan. The extent of the inhibition effect depends on the degree of substitution. The only product of enzymic reaction is D-galactopyranuronic acid, what indicates that no degradation of the terminal substituted unit of O-acetyl derivative of pectic acid takes place. Substitution of hydroxyl groups influences the affinity of the enzyme towards the modified substrate. The results let us presume that hydroxyl groups at C(2) and C(3) of galacturonic unit of pectic acid are essential for formation of the enzyme-substrate complex.

Mass transfer in heterogeneous system enzyme-substrate; Approximate analytical model for the case of liquid substrate-immobilized enzyme

1982 ◽  
Vol 47 (11) ◽  
pp. 3013-3018
Author(s):  
František Kaštánek ◽  
Jindřich Zahradník ◽  
Germanico Ocampo
Keyword(s):  
Mass Transfer ◽  
Heterogeneous System ◽  
Immobilized Enzyme ◽  
Enzymatic Reaction ◽  
Analytical Form ◽  
Approximate Model ◽  
Basic Type ◽  
Reaction Interface ◽  
Enzyme Substrate ◽  
Flow Intensity

Calculation procedure is suggested for flow intensity of substrate toward reaction interface of immobilized enzyme at simultaneous effect of enzymatic reaction and internal diffusion. The approximate model is presented in an analytical form for the basic type of Michaelis-Menten kinetics and for the case of inhibition in excess of substrate.

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