Attempted hydrolysis

The Latin word for sugar is saccharum and the derived term saccharide is the basis of a system of carbohydrate classification A monosaccharide is a simple carbohydrate one that on attempted hydrolysis is not cleaved to smaller carbohydrates Glucose (C6H12O6)... 

Attempted Hydrolysis of S-b-MM with KOH. A solution of S-b-MM-90/10-wt (1.50 g, 1.5 meq MM) in 1 9 water-THF (50 mL) was treated with KOH (1.57 g, 28.0 mmol), and the mixture was refluxed for 47 hr. The solvents were evaporated, and the residue was shredded in a blender containing 200 mL of water. The solids were filtered, washed with water and methanol, and dried. The dried polymer was dissolved in dichloromethane and precipitated from methanol. The precipitate was washed with methanol and dried in a vacuum oven, yielding 1.23 g of product. Both 1H NMR and IR indicate essentially unreacted S-b-MM. 

Attempted Hydrolysis of S-b-tBM with KOH. Using the same procedure as that described above for the attempted hydrolysis of S-b-MM, 1.57 g of S-b-tBM-87/13-wt (1.4 meq tBM) yielded 1.35 g of product. IR analysis indicated that essentially no reaction had occurred. 

An unexpected ring contraction reaction has been reported. The attempted hydrolysis of 3-methoxycarbonyl-177-thieno[2,3-< ][l,3,4]thiadiazine 4,4-dioxide 77 under acidic conditions gave the ring-contracted thieno[2,3-<7][l,2,3]thia-diazole 78 instead of the expected carboxylic acid (Equation 24). A similar mechanism to the Hurd-Mori reaction has been proposed for this transformation <2000JHC191>. 

Attempted hydrolysis of the ester group in the thienothiadiazine 66 using H2SO4 and AcOH at 100 °C gave a moderate yield of the ring-contracted thieno[2,3-carboxylic acid. Compound 67 was... 

In the oxygen analogue, the enone itself is sufficiently electrophilic that attempted hydrolysis of the THP ether in enone 55 only produces the ring expanded cyclobutanone (eq. 54)96). The overall result of this sequence for electrophilic partners constitutes a 2-oxocyclobutylation alpha to a carbonyl group (see Eq. 53). 

Attempts to prepare 2,3,5,6-tetraaminopyrazine (91) by Hoffman degradation of the diamide (88) were unsuccessful. This is apparently due to both intermolecular and intramolecular urea formation from the intermediate isocyanate giving a mixture of products, which upon attempted hydrolysis to 91 undergo a significant amount of attack on the pyrazine ring (70UP1). 

In relation to these solvolyses is the formation of free 2,5-anhydro-L-idose upon attempted hydrolysis of 5,6-anhydro-1,2-O-isopropylidene-a-D-gluco-furanose.364... 

Conversion of the isolated A-TBDMS carboxylic acid 111 to the active ester and reaction with amino acid esters yielded after desilylation the /3-sultam peptides 112 and 113. Removal of the protecting groups was also possible with benzylic esters but attempted hydrolysis of alkyl ester groups resulted in hydrolysis of the /3-sultam ring. Catalytic hydrogenation of the benzyl esters afforded the N-silylated /3-sultam peptides 114 in quantitative yields (Scheme 34) <2004M979>. 

Attempted hydrolysis [58] of the acetamide moiety in 97 (Scheme 35) in 35% hydrochloric acid instead resulted in rearrangement and desulfonation to afford the 2-aminopyridine derivative 98. 

Further examples have been provided of Schmidt rearrangement of 6a-methyl-A -3-ketones, ° A -3-ketones, 3)S-chloro-5a-6-ketones, and 3 -acetoxy-A -6-ketones, ° as well as Beckmann rearrangement of the oximes of 5) -3-ketones, A -3-ketones, A -7-ketones, 3)5-chloro-5a-6-ketones, 17-ketones, and 3a,5a-cyclo-6-ketones. In the last case, attempted hydrolysis of the resulting 6-aza-3a,5a-cyclo-B-homocholestan-7-one afforded only the products of retro-Beckmann rearrangement. Similar rearrangements have been described on 2-oxo- and 3-oxo-5a,10a-androstanes and on 17-acyloxypregn-... 

Attempted hydrolysis of the acetate function of the 10a-8jS,9j5-epoxide (303) with dilute methanolic potassium hydroxide afforded, via retro-aldol type cleavage, the 8,9-seco-steroid (304). 

When the bislactim ether of the diketopiperazine (114) is metallated with Bu"Li, deprotonation occurs exclusively a to the methyl substituent to provide an anion that undergoes highly selective reaction with aldehydes and ketones to generate adducts of the general type (115). As before, these adducts undergo dehydration to form a-methyl-a-alkenylglycines (116 Scheme 47), but attempted hydrolysis of these adducts gives a mixture of products because of preferential retroaldol reactions. 

This method was used to methylate an amide group of a tetracycline attempted hydrolysis of amide groups of tetracyclines leads to complete decomposition. 

Treatment of mangiferin with hydriodic acid in phenol, under reflux for 6 hours, was shown by Iseda, and also by the later workers, to give 1,3,6,7-tetrahydroxyxanthone (24) in good yield. Attempted hydrolysis... 

Treatment of enol ether (73 R = Et) with sodium hydroxide in aqueous ethanol affords the hydrolysis product, (73 R = H), in 74% yield. Attempted hydrolysis under acidic conditions leads only to intractable mixtures of products <89CPB1694>. 

The Latin word for sugar is saccharum, and the derived term saccharide is the basis of a system of carbohydrate classification. A monosaccharide is a simple carbohydrate, one that on attempted hydrolysis is not cleaved to smaller carbohydrates. Glucose (C6H12O6), for example, is a monosaccharide. A disaccharide on hydrolysis is cleaved to two monosaccharides, which may be the same or different. Sucrose—common table sugar—is a disaccharide that yields one molecule of glucose and one of fructose on hydrolysis. 

Because of its basic nature the compound is tested with acetic anhydride. Since the reaction product is insoluble in dilute acid, we conclude that the unknown is either a I or II amine, but the siilfoiiN l chloride test in this case will not differentiate between these two classes. Why not Attempted hydrolysis bj boiling in both acid and alkaline solution (why may aqueous instead of alcoholic solutions be used ) indicates the presence of a substance stable towards hydrolysis. 

Scheme 12.7. Attempted hydrolysis of 11 leading to the formation of corannulene core.

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