Ester with NaOH

Hydrolysis of the ester with NaOH and p-lactone formation gave the propyl analogue 206 of 113 in >20% yield from simple starting materials over ten steps. 

Saponification is the hydrolysis of an ester with NaOH or KOH to give alcohol and sodium or potassium salt of the acid. The term originated from the alkaline hydrolysis of fatty oils which led to formation of soaps. 

To about ro ml. of the ester add about 0 5 g. of 3,5-dim trobenzoic acid and 0 25 ml. of cone. H3SO4. Heat the mixture gently under reflux for 5 minutes. Add very carefully about 10 ml. of water, make alkaline with NaOH and filter at the pump. Recrystallise the solid 3,5-dinitrobenzoate from benzene and take the m.p. (M.ps., pp. 536-530.)... 

MetaUic ions are precipitated as their hydroxides from aqueous caustic solutions. The reactions of importance in chlor—alkali operations are removal of magnesium as Mg(OH)2 during primary purification and of other impurities for pollution control. Organic acids react with NaOH to form soluble salts. Saponification of esters to form the organic acid salt and an alcohol and internal coupling reactions involve NaOH, as exemplified by reaction with triglycerides to form soap and glycerol,... 

Me2Sn(SMe)2, BF3-Et20, PhCH3, 0°, 3-24 Ji AcOH, 75-100% yield." An ethyl ester can be hydrolyzed in the presence of an MEC ester with 1 N aqueous NaOH-DMSO (1 1), and MEC esters can be cleaved in the presence of ethyl, benzyl, cinnamyl, and t-butyl esters as well as the acetate, TBDMS and MEM ethers. 

As described in Section 1.7.1, the utility of the Wenker reaction is limited to substrates without labile functionalities because of the involvement of strong acid and then strong base. The Fanta group prepared a variety of aziridines by taking advantage of the Wenker reaction.For example, 6-aza-bicyclo[3.1.0]hexane (14) was produced from the ring-closure of ( )-rra s-2-aminocyclopentanol hydrochloride (13). In a similar fashion, sulfate ester 16 was prepared from A-methyl dl-trans- >-ssmnoA-hydroxytetrahydrofuran (15). Subsequent treatment of sulfate ester 16 with NaOH then delivered aziridine I . " Additional examples of Wenker aziridine synthesis may also be found in references 15-17. 

Due to the abundance of epoxides, they are ideal precursors for the preparation of P-amino alcohols. In one case, ring-opening of 2-methyl-oxirane (18) with methylamine resulted in l-methylamino-propan-2-ol (19), which was transformed to 1,2-dimethyl-aziridine (20) in 30-35% yield using the Wenker protocol. Interestingly, l-amino-3-buten-2-ol sulfate ester (23) was prepared from l-amino-3-buten-2-ol (22, a product of ammonia ring-opening of vinyl epoxide 21) and chlorosulfonic acid. Treatment of sulfate ester 23 with NaOH then led to aziridine 24. ... 

Spirapril (37) is a clinically active antihypertensive agent closely related structurally and mechanistically to enalapril. Various syntheses are reported with the synthesis of the substituted proline portion being the key to the methods. This is prepared fkim l-carbobenzyloxy-4-oxopro-line methyl ester (33) by reaction with ethanedithiol and catalytic tosic acid. The product (34) is deprotected with 20% HBr to methyl l,4-dithia-7-azospiro[4.4 nonane-8-carboxylate (35), Condensation of this with N-carbobenzyloxy-L-alanyl-N-hydroxysuccinate leads to the dipeptide ester which is deblocked to 36 by hydrolysis with NaOH and then treatment with 20% HBr. The conclusion of the synthesis of spirapril (37) follows with the standard reductive alkylation [11]. 

The opening of N-unsubstituted aziridine-2-carboxlic esters with sodium bisulfite was recently described by Xu [113]. Thus, treatment of (S)-151 (Scheme 3.54) with NaHS03 followed by NaOH afforded (J )-cysteic acid 152 in 74% yield. (S)-Cysteic acid was prepared similarly in 72 % yield. 

For a further separation of the sulfonated surfactants the latter are heated for 4 h with 2 N HC1. The methyl ester sulfonates are split into methanol and a-sulfo fatty acids, which form disodium salts after neutralization with NaOH. The product mixture from acid hydrolysis can be separated by extraction with petroleum ether. For example, the fatty alcohols formed from fatty alcohol sulfo-... 

Urine Extraction of sample with polydithio-carbamate resin and NaOH filtration on cellulose ester membrane neutralization with NaOH ashing dissolution and heating dilution with distilled water ICP/AES (Method P CAM 8310) 0.005 pg/mL 100 NIOSH 1984... 

The formation of an ester from an alcohol and an acid is an equilibrium reaction. The reverse reaction can be promoted by removing the acid from the reaction mixture, for example by treating it with NaOH. Animal fats are converted to soaps (fatty acid salts) and glycerine (a trialcohol) in this manner. 

Worked Example 8.16 The reaction of the ester ethyl methanoate and sodium hydroxide in water is performed with NaOH in great excess ([NaOH]o = 0.23 mol dm-3). The reaction has a half-life that is independent of the initial concentration of ester present. 13.2 per cent of the ester remains after 14 min and 12 s. What is the second-order rate constant of reaction k2l... 

We will answer this question by first thinking about a typical undergraduate experiment designed to follow reaction kinetics. Imagine that we want to hydrolyse an ester with sodium hydroxide solution. At the start of the experiment, the extent of reaction, is zero, so the concentration of NaOH is equal to its initial value. 

Hydrolysis of the ester (94) with NaOH and adjustment of the resulting solution to pH 2 leads to rapid decarboxylation and deprotection to the alcohol (95). Subsequent oxidation with Mn02 gives the ketone (96) which undergoes addition with PhMgBr to yield the tertiary alcohol (97) (Scheme... 

Hydrolysis of the ester with 1 equivedent of NaOH, at room tempera-tme, gives the free acid. Its chloride, amide, hydrazide and azide are also knovm (62a). 

Opening of the dithiazole ring of the imidazolo[4,5-r7 [l,2,3]dithiazole 107 was employed as a key step in a multistep synthesis leading to hydroxamic acid derivatives 108 and 109 which are under investigation as matrix metalloproteinase inhibitors. Following initial reaction of 107 with NaOH treatment with 2-bromo-3-(4-chlorophenyl)propionic acid tert-butyl ester lead to the thioethers 108 from which 109 could be obtained (Scheme 10). <2000W0063197>. 

The synthesis of pyrido[4,3-rf]pyrimidine-2,4-diones was carried out by thermal fusion of enamine 601 with A-methylurea at 180 °C to give the pyridopyrimidines 156 and 607 in addition to the unexpected a,/3-unsaturated esters 608, which were separated chromatographically in very poor yield (Equation 51). Alternatively, 156 was obtained in 59% yield by treatment of 601 with methyl isocyanate and EtsN to give the corresponding uriedo intermediate which was cyclized in situ with NaOH <1994JHC1569>. 

Amino acid-modified furocoumarins were prepared by condensation of the T-hydroxysuccinimide ester of 3-(2,3,5-trimethyl-7-oxofuro[3,2-g]chromen-6-yl)propanoic acid 51 with amino acids <2003JPH177>. Ethyl 3-(7-hydroxy-4-methyl-2-oxo-2/7-3-chromenyl)propanoate 49, prepared in 56% yield by Pechmann condensation of resorcinol and diethyl 2-acetylglutarate in the presence of HCl, was condensed with 3-chlorobutan-2-one in the presence of base to give propanoate 50 (Scheme 4). The MacLeod method was then used to fuse a furan ring to the benzopyran-2-one system. Heating 50 with NaOH solution (1 M) readily cyclized it into the corresponding psoralen furocoumarin 51 with simultaneous hydrolysis of the ester. 

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