The chemistry of 2,1-benzisothiazoles. IX. The reaction of 3-chloro-substituted 2,1-benzisothiazoles with nucleophiles and the preparation of(2,1-Benzisothiazol-3-yl)acetic acid

1975 ◽  
Vol 28 (9) ◽  
pp. 2051 ◽  
Author(s):  
M Davis ◽  
E Homfeld ◽  
J McVicars ◽  
S Pogany
Keyword(s):  
Acetic Acid ◽  
Acid Hydrolysis ◽  
Auxin Analogue ◽  
Hydrolysis Of

3-Chloro-2,1-benzisothiazole (2; R = H, R? = Cl) and 3,5-dichloro-2,1- benzisothiazole (2;R,R? = Cl) react readily with nucleophiles, and yield 3-substituted products. Acid hydrolysis of one such product, ethyl (2,1-benzisothiazol-3-yl)cyanoacetate (2; R = H, R? = CH(CN)CO2Et),affords (2,1-benzisothiazol-3-yl)acetic acid (2; R = H, R? = CH2CO2H), an auxin analogue.

Cyclitols. XXXII. Cyclopentanepentols

1970 ◽  
Vol 23 (9) ◽  
pp. 1831 ◽  
Author(s):  
SJ Angyal ◽  
BM Luttrell
Keyword(s):  
Acetic Acid ◽  
Acid Hydrolysis ◽  
Strong Acid ◽  
Equilibrium Mixture ◽  
Relative Stabilities ◽  
Hydrolysis Of

Three cyclopentanepentols have been synthesized: the 1,2,4/3,5-isomer by acid hydrolysis of an anhydro-cyclopentanepentol, DL-1,2-anhydro-4,5-O-cyclohexylidene-1,2,3/4,5-cyclopentanepentol; the 1,2,3/4,5-isomer by deamination of (1,4/2,3,5)-5-amino-1,3-di-O-acetyl-2,3-O-cyclohexylidene-l,2,3,4-cycopentanetetrol; and the 1,2,3,4/5-isomer by solvolysis of two tetra-O-acetyl-O-tosylcyclopentanepentols. An equilibrium mixture of the three cyclopentanepentols was obtained by heating one of them with 95% acetic acid in the presence of a strong acid. The relative stabilities of the three isomers are in the order 1,2,4/3,5 > 1,2,3/4,5 > 1,2,3,4/5.

Synthesis of 4-deoxydaunosamine and 4-deoxyristosamine

1980 ◽  
Vol 58 (16) ◽  
pp. 1751-1758 ◽  
Author(s):  
Hans H. Baer ◽  
Hanna R. Hanna
Keyword(s):  
Acetic Acid ◽  
Acid Hydrolysis ◽  
Sodium Borohydride ◽  
Catalytic Hydrogenation ◽  
Sodium Acetate ◽  
Amino Glycoside ◽  
Hydrolysis Of

Treatment of methyl 3,6-dideoxy-2,4-di-O-methylsulfonyl-3-nitro-α-L-glucopyranoside (2) with sodium acetate and acetic acid in acetone gave methyl 4-O-acetyl-2,3,6-trideoxy-3-nitro-α-L-erythro-hex-2-enopyranoside (3) as a kinetic product, and the 2-O-acetyl-3,4,6-trideoxy-3-nitro-α-L-threo-hex-3-eno isomer 4 as the thermodynamically preferred product. Treatment of 2 or 4 with sodium borohydride produced a separable mixture of methyl 2,3,4,6-tetradeoxy-3-nitro-α-L-threo-hexopyranoside (5) and its α-L-erythro epimer (6), the latter being convertible into the former by base-catalyzed epimerization. Acid hydrolysis of 5 and 6 afforded the corresponding free nitro sugars 7 and 8. Catalytic hydrogenation of 5 led to the corresponding amino glycoside, isolated as the acetate 9 or hydrochloride 10; similarly, 6 gave the epimeric amine which was isolated as its acetate 14 or picrate 15. N-Trifluoroacetylation of 9 provided the N-trifluoroacetyl glycoside 12 which was hydrolyzed to give a 49% yield (overall from 2) of 2,3,4,6-tetradeoxy-3-trifluoroacetamido-L-threo-hexose (4-deoxy-N-trifluoroacetyldaunosamine, 13). Analogously, 14 afforded the epimeric N-trifluoroacetyl glycoside 17 which was hydrolyzed to give a 28% overall yield of 2,3,4,6-tetradeoxy-3-trifluoroacetamido-L-erythro-hexose (4-deoxy-N-trifluoroacetylristosamine, 18).

Microwave-Assisted Organic Acid Hydrolysis of Corncob in Bioethanol Production

2014 ◽  
Vol 1033-1034 ◽  
pp. 151-154
Author(s):  
Sininart Chongkhong ◽  
Chakrit Tongurai
Keyword(s):  
Acetic Acid ◽  
Acid Solution ◽  
Organic Acid ◽  
Acid Hydrolysis ◽  
Acid Concentration ◽  
Low Cost ◽  
Heating Time ◽  
Microwave Assisted ◽  
Bakery Yeast ◽  
Hydrolysis Of

The microwave-assisted hydrolysis of carbohydrate from corncob using acetic acid was investigated by response surface methodology. The sequence of variables affecting total reducing sugar concentration in the hydrolyzate was the ratio of corncob to acid solution > acid concentration > microwave heating time. The highest 84.2 g/L glucose concentration was obtained by 0.5 M acetic acid concentration with 0.40:1 corncob to acid solution ratio at 900 W microwave power for 10 min. The hydrolyzate prepared from the optimal hydrolysis condition was fermented by 8%w bakery yeast with pH 5.25 at 28°C for 62 h to achieve the optimum ethanol concentration of 32.2 g/L. This proposed that microwave-assisted organic acid hydrolysis is potential for producing fermentable sugars, and suggested that a two-step process for the ethanol is the satisfied production because of low cost, save energy consumption and friendly to environment.

Organic material dissolved during oxygen-alkali pulping of hot water extracted birch sawdust

TAPPI Journal ◽  
2015 ◽  
Vol 14 (4) ◽  
pp. 237-244 ◽  
Author(s):  
JONI LEHTO ◽  
RAIMO ALÉN
Keyword(s):  
Acetic Acid ◽  
Betula Pendula ◽  
Cooking Time ◽  
Hot Water ◽  
Partial Hydrolysis ◽  
Chemical Pulping ◽  
Black Liquors ◽  
Aliphatic Carboxylic Acids ◽  
Hydrolysis Of ◽  
Cooking Conditions

Untreated and hot water-treated birch (Betula pendula) sawdust were cooked by the oxygen-alkali method under the same cooking conditions (temperature = 170°C, liquor-to-wood ratio = 5 L/kg, and 19% sodium hydroxide charge on the ovendry sawdust). The pretreatment of feedstock clearly facilitated delignification. After a cooking time of 90 min, the kappa numbers were 47.6 for the untreated birch and 10.3 for the hot water-treated birch. Additionally, the amounts of hydroxy acids in black liquors based on the pretreated sawdust were higher (19.5-22.5g/L) than those in the untreated sawdust black liquors (14.8-15.5 g/L). In contrast, in the former case, the amounts of acetic acid were lower in the pretreated sawdust (13.3-14.8 g/L vs. 16.9-19.1 g/L) because the partial hydrolysis of the acetyl groups in xylan already took place during the hot water extraction of feedstock. The sulfur-free fractions in the pretreatment hydrolysates (mainly carbohydrates and acetic acid) and in black liquors (mainly lignin and aliphatic carboxylic acids) were considered as attractive novel byproducts of chemical pulping.

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%.

Sign in / Sign up

Export Citation Format

Share Document