Hydrolysis acidic, mild

In a similar vein, acylation of the corticoid 50 with furoyl chloride gives the diacyl derivative 51. Reduction with sodium borohydride serves to convert the 11-ketone to the alcohol 52. Hydrolysis under mild acid conditions preferentially removes the acyl group at the less hindered 21 position. The hydroxyl group in that derivative (53) is then converted to the mesylate 54. Replacement by chlorine affords mometasone (55) [12]. 

Esters 174 undergo hydrolysis under mild conditions to give the corresponding carboxylic acids 175 in excellent yields (Equation 15) <2004JOC4974>. 

The polysaccharide component of a lipopolysaccharide can be separated from the lipid component by selective hydrolysis of the glyco-sidic linkages of the 3-deoxy-D-manno-octulosonic acid residues connecting these two components. The conditions for the hydrolysis are mild, namely, 0.1 M acetic acid for 1.5 h at 100° (Ref. 18). Similar conditions, namely, M formic acid for 1 h at 100° or 0.05 M hydrogen chloride in methanol for 1 h at 85°, were used to split off the sialic acid residues from gangliosides.19,20... 

Further examples of modified Smith degradation, in which the polyalcohol is methylated prior to hydrolysis under mild conditions, uronic acid degradation, and /3-elimination preceded by oxidation have been reported in connection with structural studies on the Klebsiella type 28 (Ref. 182), 57 (Ref. 183), 59 (Ref. 142), and 81 (Ref. 184) capsular polysaccharides. 

Imines capable of forming bicyclic chelate rings as in (114) are known to be stabilized towards hydrolysis under mildly acidic conditions.392 However, imines which can form monocyclic chelates such as N,N -ethylenebis(2-thienylmethyleneimine) (115)39CI 391 4CI2 404 and N,lV -ethylenebis(2-furanylmethyleneimine) (116)403,405,406 where the S and O atoms respectively do not act as donors are rapidly hydrolyzed in the presence of copper(II) and nickel(II) ions. Hydrolysis of a bicyclic metal complex such as (114) involves the rupture of chelate rings, a process which is not normally favoured. 

IR spectroscopy Removal of sulfate by hydrolysis in mild acid Removal of sulfate by solvolysis in dioxane Removal of sulfate by aryl-sulfatase A... 

The alkene s HOMO interacts with the isocyanate s LUMO, and the most electrophilic atom is the carbonyl carbon so this is where the terminal carbon atom of the alkene attacks. The chlorosulfonyl group can be removed simply by hydrolysis under mild conditions via the sulfonic acid. 

Iminothiazolidinones (e.g., 10) easily undergo acid-base hydrolysis under mild conditions to afford the corresponding diones (42).6 7-10,26,28,30,40 43,... 

The nitrilase mediated DKR route to enantiomerically pure 2-hydroxycarboxylic acids is restricted to the (R)-enantiomers because, to our knowledge, no (S)-selec-tive nitrilases for cyanohydrin substrates are commonly available [11]. We reasoned that a fully enzymatic route to the (S)-acids should be possible by combining an (S)-selective oxynitrilase (hydroxynitrile lyase, EC 4.1.2.10, (S)-hydroxynitrile lyase) and a non-selective nitrilase in a bienzymatic cascade (see Figure 16.3). Besides being more environmentally acceptable than chemical hydrolysis, the mild reaction conditions of the combined enzymatic reaction would be compatible with a wide range of hydrolysable groups. 

Because imines and enamines are formed by a set of reversible reactions, both can be converted back to carbonyl compounds by hydrolysis with mild acid. The mechanism of these reactions is exactly the reverse of the mechanism written for the formation of imines and enamines. In the hydrolysis of enamines, the carbonyl carbon in the product comes from the hybridized carbon bonded to the N atom in the starting material. 

Occurrence. D-f/treo-Pentulose 5-phosphate (d-xylulose 5-phosphate) is an intermediate in the metabolism of xylose in bacteria, and is also formed from d-erythro-pentulose 5-phosphate in the presence of an epimerase.57 D- /m o-PcnLulose has been found in a lipopolysaccharide from Pseudomonas diminuta, from which it was obtained after hydrolysis by mild acetic acid as used to release lipid A.58 It was also found in the LPS of a Yersinia enterocolitica serologic variant.59... 

Hydrolysis with mild acid leads to selective reversal of the silyl cyanohydrin formation, thus revealing the ketone at C17. Condensation of that function with lithium acetylide proceeds as in all cases noted earlier to give the 17a-ethynyl-17/3-hydroxy intermediate 31-2 (Scheme 4.31). Treatment of that intermediate with acid then leads to hydrolysis of the ketal at position 3. The transient intermediate hydroxy ketone quickly loses water so as to form an olefin at C4 and thus mifepristone (31-3). 

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