Fischer Indole Synthesis with Selected 2,3-Dideoxy-D-glycero-aldopentose Derivatives. Conversion of D-Xylose to (2S)-3-(Indol-3-yl)propane-1,2-diol

1996 ◽  
Vol 61 (2) ◽  
pp. 298-304 ◽  
Author(s):  
Stevan Lajšic ◽  
Gordana Cetkovic ◽  
Mirjana Popsavin ◽  
Velimir Popsavin ◽  
Dušan Miljković
Keyword(s):  
Acid Hydrolysis ◽  
Raney Nickel ◽  
Good Yield ◽  
Dimethyl Acetal ◽  
Fischer Indole Synthesis ◽  
Fischer Indolization ◽  
Efficient Route ◽  
Indole Synthesis ◽  
Hydrolysis Of

Two independent routes towards (2S)-3-(indol-3-yl)propane-1,2-diol (11) were achieved starting from 3,5-di-O-acetyl-1,2-O-cyclohexylidene-α-D-xylofuranose (1). Ethanethiolysis of 1 afforded acyclic diethyl dithioacetal 2 which was further O-deacetylated to give 3. Selective benzoylation of 3 gave 5-O-benzoyl derivative 4. Treatment of 4 with N-bromosuccinimide in methanol gave methyl furanoside 5 which was further desulfurized over Raney nickel to afford 6. An acid hydrolysis of 6 gave hemiacetal 7 which upon treatment with phenylhydrazine, according to standard Fischer indolization procedure, yielded a mixture of chiral indoles 10. O-Debenzoylation of 10 gave the crystalline diol 11. A more efficient route towards the chiral indole 11 included the initial dethioacetalation of 2 into dimethyl acetal 8 which was further desulfurized over Raney nickel to give the corresponding 2,3-dideoxy derivative 9. Direct Fischer indolization of 9 with phenylhydrazine, followed by O-deacetylation of intermediate 12, afforded the expected indole 11 in good yield.

A new convenient synthetic route towards 2-(hetero)aryl-substituted thieno[3,2-b]indoles using Fischer indolization

2018 ◽  
Vol 16 (26) ◽  
pp. 4821-4832 ◽  
Author(s):  
Roman A. Irgashev ◽  
Alexander S. Steparuk ◽  
Gennady L. Rusinov
Keyword(s):  
Synthetic Route ◽  
Fischer Indole Synthesis ◽  
Fischer Indolization ◽  
Indole Synthesis

A series of 2-(hetero)aryl-substituted thieno[3,2-b]indoles has been successfully prepared using an effective three-step strategy based on Fischer indole synthesis.

BROMINATION OF STEROID 20-KETALS

1959 ◽  
Vol 37 (2) ◽  
pp. 345-350 ◽  
Author(s):  
Arthur A. Amos ◽  
P. Ziegler
Keyword(s):  
Methyl Ester ◽  
Acid Hydrolysis ◽  
Good Yield ◽  
Acid Methyl Ester ◽  
Acid Methyl ◽  
Hydrolysis Of

Bromination of 3α,12α-diacetoxypregnan-20-one ethylene ketal provided in good yield the corresponding 21-monobromo compound. This product, on acid hydrolysis and subsequent acetolysis, gave the known 3α,12α,21-triacetoxypregnan-20-one. Acid hydrolysis of the bromoketal, followed by Faworsky rearrangement, led to 3α,12α-diacetoxy-17α-methyletiocholanic acid methyl ester.

scholarly journals Synthesis of Sepiapterin-C via Hydrolysis of 6-Ethynylpteridine

2014 ◽  
Vol 9 (1) ◽  
pp. 1934578X1400900
Author(s):  
Winston Nxumalo ◽  
Andrew Dinsmore
Keyword(s):  
Acid Hydrolysis ◽  
Good Yield ◽  
Partial Reduction ◽  
Mercury Oxide ◽  
Hydrolysis Of

Acid hydrolysis of 6-ethynylpteridine catalyzed by mercury oxide gives 6-acetyl-2-amino-3,4-dihydropteridin-4-one in good yield. Partial reduction of the product with dissolved Al in NH3 solution afforded sepiapterin-C.

DETERMINATION OF MICRO-AMOUNTS OF 5β-PREGNAN-3α-OL-20-ONE IN URINE USING INFRARED-SPECTROMETRY

1962 ◽  
Vol 41 (2) ◽  
pp. 234-246 ◽  
Author(s):  
H. J. van der Molen
Keyword(s):  
Infrared Spectrum ◽  
Quantitative Determination ◽  
Acid Hydrolysis ◽  
Chromatographic Separation ◽  
Pure Form ◽  
Infrared Spectrometry ◽  
Hydrolysis Of

ABSTRACT A procedure for the quantitative determination of 5β-pregnan-3α-ol-20-one in urine is described. After acid hydrolysis of the pregnanolone-conjugates in urine, the free steroids are extracted with toluene. Pregnanolone is isolated in a pure form as its acetate; after chromatographic separation of the free steroids on alumina, the fraction containing pregnanolone is acetylated and rechromatographed on alumina. Quantitative determination of the isolated pregnanolone-acetate is carried out with the aid of the infrared spectrum recorded by a micro KBr-wafermethod. The reliability of the method under various conditions is discussed under the headings, specificity, accuracy, precision and sensitivity. It is possible to determine 30–40 μg pregnanolone in a 24-hours urine portion with a precision of 25%.

Optimization of technological modes of cold acid hydrolysis of potato starch

2020 ◽  
Vol 26 (3) ◽  
pp. 222-233
Author(s):  
M. Alekseenko ◽  
V. Litvyak ◽  
A. Sysa ◽  
E. Hrabovska ◽  
O. Galenko
Keyword(s):  
Acid Hydrolysis ◽  
Potato Starch ◽  
Hydrolysis Of

FLOWTHROUGH ACID HYDROLYSIS OF RAPESEED STALKS

2012 ◽  
Vol 11 (12) ◽  
pp. 2313-2318
Author(s):  
Theodor Malutan ◽  
Adina Elena Panzariu
Keyword(s):  
Acid Hydrolysis ◽  
Hydrolysis Of

scholarly journals Tagasaste, leucaena and paulownia: three industrial crops for energy and hemicelluloses production

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alberto Palma ◽  
Javier Mauricio Loaiza ◽  
Manuel J. Díaz ◽  
Juan Carlos García ◽  
Inmaculada Giráldez ◽  
...  
Keyword(s):  
Activation Energy ◽  
Acid Hydrolysis ◽  
Energy Production ◽  
Combustion Process ◽  
Operating Conditions ◽  
Raw Material ◽  
Energy Of Combustion ◽  
Increasing Temperature ◽  
Hydrolysis Of ◽  
Chamaecytisus Proliferus

Abstract Background Burning fast-growing trees for energy production can be an effective alternative to coal combustion. Thus, lignocellulosic material, which can be used to obtain chemicals with a high added value, is highly abundant, easily renewed and usually inexpensive. In this work, hemicellulose extraction by acid hydrolysis of plant biomass from three different crops (Chamaecytisus proliferus, Leucaena diversifolia and Paulownia trihybrid) was modelled and the resulting solid residues were used for energy production. Results The influence of the nature of the lignocellulosic raw material and the operating conditions used to extract the hemicellulose fraction on the heat capacity and activation energy of the subsequent combustion process was examined. The heat power and the activation energy of the combustion process were found to depend markedly on the hemicellulose content of the raw material. Thus, a low content in hemicelluloses resulted in a lower increased energy yield after acid hydrolysis stage. The process was also influenced by the operating conditions of the acid hydrolysis treatment, which increased the gross calorific value (GCV) of the solid residue by 0.6–9.7% relative to the starting material. In addition, the activation energy of combustion of the acid hydrolysis residues from Chamaecytisus proliferus (Tagasaste) and Paulownia trihybrid (Paulownia) was considerably lower than that for the starting materials, the difference increasing with increasing degree of conversion as well as with increasing temperature and acid concentration in the acid hydrolysis. The activation energy of combustion of the solid residues from acid hydrolysis of tagasaste and paulownia decreased markedly with increasing degree of conversion, and also with increasing temperature and acid concentration in the acid hydrolysis treatment. No similar trend was observed in Leucaena diversifolia (Leucaena) owing to its low content in hemicelluloses. Conclusions Acid hydrolysis of tagasaste, leucaena and paulownia provided a valorizable liquor containing a large amount of hemicelluloses and a solid residue with an increased heat power amenable to efficient valorization by combustion. There are many potential applications of the hemicelluloses-rich and lignin-rich fraction, for example as multi-components of bio-based feedstocks for 3D printing, for energy and other value-added chemicals.

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