Hydrolysis using LiOH

Conformationally constrained 2 -deoxy-4-thia /3-anomeric spirocyclic nucleosides have been synthesized by Dong and Paquette <2005JOC1580>. Osmium-catalyzed dihydroxylation of the spirocyclic dihydrothiophene 135 in the presence of DABCO gave the air-diol 136 in 53% yield which was protected as an acetonide hydrolysis using LiOH in aqueous THE and subsequent Meerwein-Ponndorf-Verley reduction of the keto compound 137 gave a diaster-eomeric mixture of alcohols (Scheme 36). 

Values of A oh for the base hydrolysis of [Co(NH3)sBr]Br2 were found to vary with the alkali-metal hydroxide used (LiOH, NaOH, or KOH), an effect which could be removed by the addition of edta ion. The cause of this rate variation was finally traced to heavy-metal impurities (Hg + and Ag+) in the alkali-metal hydroxide solutions. ... 

Hence, the hydrolysis of the imide can be performed using LiOH [51] however, when the substrates are too hindered, the regioselectivity of the hydroxide addition can be altered leading to the ring opening of the oxazolidinone. To... 

Lithium methylate (lithium methoxide) [865-34-9] M 38.0. Most probable impurity is LiOH due to hydrolysis by moisture. It is important to keep the sample dry. It can be dried by keeping in a vacuum at 60-80° under dry N2 using an oil pump for a few hours. Store under N2 in the cold. It should not have bands above 3000cm-> IR has VKBr 1078, 2790, 2840 and 2930cm-. [JOrgChem 21 156 7956.]... 

These supported cycloadducts were then treated with a base (LiOH, NaOH) in a mixture of water and alcohol to give the expected free acid derivatives. However, while the latter compounds were readily recovered, the same was not true for the ionic liquid 4b, which was obtained as a dark brown liquid impure by NMR analysis. Very likely, the basic hydrolysis of the ester function caused the deprotonation of the imidazolium ring leading to a series of undesired side-reactions. Therefore, milder reaction conditions were explored to cleave the Diels-Alder product from the ionic liquid support. Handy and Okello found that the best method was the cyanide-mediated transesterification that gave the corresponding methyl esters 9-11 and allowed recover of 4b in at least 90% yield. It was also demonstrated that the recovered 4b could be used for further supported syntheses. In fact, in two subsequent mns the yields of the final ester compound were similar, indicating that the ionic liquid 4b could be efficiently recycled. 

Hydrolysis of lactams. The N-Boc derivatives of lactams are hydrolyzed to Boc derivatives of w-amino acids by treatment with LiOH (3 equiv.) in aqueous THF at 25° in 85-95% yield. Treatment with NaOCH-, in t H,OH at 0° affords the esters of these products. The same reactions are useful for hvdrolysis or methanolysis of secondary amides. ... 

EtsN in CH2CI2 in the presence of 4-dimethylaminopyridine (Scheme 13.68). Dihydroxylations of the trimethylsilyl ethers of 217 and 218 generate the 4-amino-4-deoxy-heptono-1,4-lactam derivatives 219 and 220, respectively [121]. Lactam hydrolysis of 219 with LiOH, followed by the Malaprade diol cleavage with NaI04 and further oxidation and deprotection, allows the preparation of 4- p/-polyoxamic acid [122]. Lactam 217 and its enantiomer derived from (5 )-24 have been converted into all four stereomers of cw-l,2-dihydroxypyrrolizidine [123]. Compounds 217 and 218 have been used also to prepare the rm/i5 -2,3-c/5 -3,4-dihydroxyprolines [124,125]. 

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