Hydrolysis with sulfurous acid

Condensation of hydrazine with ethoxymethylenemalononitrile (22) gives 3-amino-4-cyanopyrazole (23). Hydrolysis with sulfuric acid leads to the amide, 24 heating with formamide inserts... 

Hydration of (R,E)-diethylenamine, followed by hydrolysis with sulfuric acid gives (+)-7-hydroxycitronellal, which is known as an artificial perfume with pleasant olfactory properties, with high optical purity (Scheme 5).9... 

The investigation showed two significant things. First, hydrolysis with sulfuric acid also caused a sharp reduction in moisture-regain but the minimum is reached only after 30 minutes of boiling. This indicated that sulfuric acid is considerably less active as a hydrolyzing agent than... 

Replacement of the pyridine ring by a more strongly basic ethylpiperidine moiety leads to the antiarrhythmic dmg disobutamide (55-5). The synthesis of this compound also involves successive carbanion alkylation reactions. Thus, reaction of the anion from ortho-chloroacetonitrile (55-1) with A-(2-chloroethyl) piperidine gives the intermediate (55-3) alkylation of the anion from this leads to (55-4). Hydrolysis with sulfuric acid completes the preparation of disobutamide (55-5) [56]. 

Pyridine derivative 358 underwent a hydrolysis with sulfuric acid to the condensed 4//-pyran 86 (R = R1 = H, R2 = 4-NOJC6H4).64 The similar 4H-... 

In the second process methyl 3,4-isopropylidene-a-D-fucopyranoside was methylated to give crystalline methyl 2-methyl-3,4-isopropylidene-a-D-fucopyranoside, from which 2-methyl-D-fucose was obtained by hydrolysis with sulfuric acid. The sugars obtained by both routes were identical. 

An alternative approach to measurement of lignin distribution is to assess variation in the porosity of wood which has been hydrolyzed to form a lignin skeleton (Donaldson 1987). Hydrolysis with sulfuric acid is particularly useful because of the swelling that occurs. This magnifies areas of the cell wall such as the S3 layer or the compound middle lamella which would otherwise be too small to measure. 

In contrast to 83 and 85, 1,2-dimethyl-4,5-dihydroimidazole (89, n = 2) and 1,2-dimethyl- 1,4,5,6-tetrahydropyrimidine (89, n = 3) underwent direct acylation with two equivalents of aroyl chloride to give diacylenediamines 90 rather than enol benzoates. Their acid hydrolysis with sulfuric acid at water bath temperatures results in cleavage of one of the aroyl groups and benzoyl-substituted 1,1-enediamines 91 are formed in moderate yields (equation 31)103. 

On hydrolysis with sulfurous acid, 5-amino-5-deoxy-l,2-0-isopro-pylidene-jS-D-arabinofuranose gives an acyclic bisulfite adduct which, on treatment with barium hydroxide, afiFords a solution of 5-amino-5-deoxy-D-arabinopyranose that behaves similarly to the analogous D-xylose compound. The Amadori rearrangement proceeds with somewhat more difiBculty. The equilibrium between the pyranose form and its dehydration product is recognizable by the presence of a positive Cotton efiFect (300 nm), a result predictable by theory, as 42 should represent the most favored conformation. 

From 51 with barium hydroxide, followed by hydrolysis with sulfurous acid, there is obtained, as the hydrochloride, the acyclic bisulfite adduct of 5,6-diamino-5,6-dideoxy-D-glucose (50). On alkaline... 

In the following experiment a thin paste of arrow-root starch was treated with malt a-amylase. The degree of hydrolysis was ascertained by titration with hypoiodite and n-glucose and maltose were determined by fermentative methods. After the fermentation, the average chain lengths of the a-dextrins was determined by titration with hypoiodite before and after complete hydrolysis with sulfuric acid. In Fig. 4, curve... 

The nitro group can be converted into other useful functional groups following conjugate addition. Reduction gives primary amines while hydrolysis reveals ketones. The hydrolysis is known as the Nef reaction and used to be achieved by formation of the nitro-stabilized anion with a base such as sodium hydroxide followed by hydrolysis with sulfuric acid. These conditions are rather unforgiving for many substrates (and products) so milder methods have been developed. One of these involves ozonolysis of the nitro enolate at low temperature rather than treatment with acid. 

Treatment of tylophorine with cyanogen bromide yields a crystalline bromocyanamide, which on treatment with sodium borohydride yields a hydroxycyanamide. The latter on hydrolysis with sulfuric acid yields tylophorine, indicating the presence of a 1 4 or 1 5 amino-alcohol system in the compound. 

Diquinolylmethanes are oxidized to diquinolylketones (13) by air-02, H2O2, or CrOa in acetic acid. - The ketones (13) can also be prepared by condensation of the diquinolylmethanes with p-nitroso-dimethylaniline, followed by hydrolysis with sulfuric acid. The ketoximes (14) undergo the Beckmann rearrangement, with PCI 5 in ether, to give amides (15). On oxidation, triquinolylmethanes give the corresponding carbinols. ... 

Hydration of 3-aryl-2-propynols. Alkenyl sulfides are formed as intermediates and these undergo hydrolysis with sulfuric acid in EtOH to afford a-ketols. 

Because of the formation of emulsions, the liquid-liquid extraction (LLE) of nonionic surfactants, e.g., APEO, is restricted to these less surface-active metabolites, i.e., APEO with one to three ethoxy units, APEC, and AP. Noncontinuous LLE of water samples with methylene chloride using a separatory funnel has been applied for NP and NPEO (one to three ethoxy units). In addition, an ultrasonic bath has been shown to be suitable for the LLE of APEOs and AEOs form water samples.Continuous LLE (percolation) has been successfully used for concentration of short-chained APEO and AP too. Steam distillation/solvent extraction using an apparatus designed by Veith and Kiwus " is a sophisticated method of concentrating steam-distillable AP and APEO (one to three ethoxy units) from water samples.AEOs have been efficiently extracted by combination of reflux hydrolysis with sulfuric acid and steam distillation with a Karlsruhe Apparatus. ... 

The presence of negatively charged sulfonic groups in CNP obtained by hydrolysis with sulfuric acid significantly affect their properties, such as the thermal stability of the nanoparticles, as well as phase stability, rheological behavior, and birefringence of nanocrystal suspensions. 

Furthermore, the CNP obtained by hydrolysis with sulfuric acid contain sulfonic groups, which reduce the thermal stability of nanoparticles. For this reason... 

It is remarkable that only 1,4- and no 1,2-dicarboxylic acids are observed. The reaction of the iron allyl complex with FeCl2 led to an unexpected product After hydrolysis with sulfuric acid in ether a linear C Q-dicarboxylic acid with two isolated double bonds was formed in yields up to 93 %. 

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