Ethyl diesters

To a soln of /V-Z-TV -Boc-L-cystine tert-butyl ethyl diester (0.96 g, 1.74 mmol) in benzene (25 mL) was added P(NEt2)3 (0.47 g, 1.91 mmol) dropwise, with stirring under N2. After stirring at rt for 5h, the solvent was removed under reduced pressure and the oily residue purified by MPLC (hexane) to yield the title compound yield 0.47 g (52%) [a]D25 +2.3 (c 7.9, CHC13). 

Hexanoic acid, 2-ethyl-, diester with tetraethylene glycol... 

EINECS 242-149-6 Flexol 4GO Hexanoic acid, 2-ethyl-, oxybis(2,1-ethyldiyloxy-2,1-ethanediyl)ester Hexanoic acid, 2-ethyl-, diester with tetraethylene glycol Plasticizer 4GO Polyethylene glycol 200 di(2-ethylhexoate) TegMeR 804 Tetraethylene glycol di(2-ethylhexoate) 3,6,9-Trioxaundecamethylene bis(2-ethylhexanoate). 

Hexanoic acid, 2-ethyl-, 1,2-ethanediylbis(oxy-2,1-ethanediyl) ester. 4-02-00-01005 (Beilstein Handbook Reference) A13-01451 BRN 1806809 EINECS 202-319-2 Flexol 3GO Flexol plasticizer 3GO Hexanoic acid, 2-ethyl-, diester with triethylene glycol Hexanoic acid, 2-ethyl-, 1,2-ethanedlylbls(oxy-2,1- Triethylene glycol, bis(2-ethyl-hexanoate) Triethylene glycol dl(2-ethylhexoate). Capital Resin Corp. 

Methyl-(-4-methoxyphenyl)-propanedioic acid acid, ethyl diester... 

Fig. 6. (A) Enantioselective hydrolysis of a-methyl phenylalanine amide (24) and a-methyl-4-hy-droxyphenylalanine amide (25) by amidase. (B) Enantioselective enzymatic hydrolysis of methyl-(4-methoxyphenyl)-propanedioic acid ethyl diester (2Z) to (5)-monoester (26).

Nimodipine (Nimotop, 2) is a dihydropyridine the isopropyl 2-methoxy-ethyl diester of l,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-pyridine-3,5-di-carboxylic acid. This molecule is marketed in a 30 mg oral formulation (as Nimotop) and is indicated for use in vascular diseases, particularly cerebrovascular diseases due to its high lipid affinity and the fact that it easily crosses the blood-brain barrier. 

The use of a condensed polymerization route [69] with 1,4-butanediol, an ethyl diester nlo side-group backbone and a titanium catalyst produces a polyester backbone (Fig. 4.10). 

Enzymatic acylation reactions offer considerable promise in the synthesis of specific ester derivatives of sucrose. For example, reaction of sucrose with an activated alkyl ester in /V, /V- dim ethyl form am i de in the presence of subtilisin gave 1 -0-butyrylsucrose, which on further treatment with an activated fatty acid ester in acetone in the presence of Hpase C. viscosum produced the 1, 6-diester derivative (71,72). 

Carbonates are indexed in Chemicaly hstracts under carbonic acid, esters. Symmetrical diesters have the prefix di or bis. Unsymmetrical diesters are listed with the two radicals following each other. For example, ethyl phenyl carbonic diester is C2H OCOOC H. Table 6 Hsts commonly used carbonates, their Chemicaly hstracts Service Registry Number, and formulas. 

Porcine liver esterase (PLE) gives excellent enantioselectivity with both dimethyl 3-methylglutarate [19013-37-7] (lb) and malonate (2b) diester. It is apparent from Table 1 that the enzyme s selectivity strongly depends on the size of the alkyl group in the 2-position. The hydrolysis of ethyl derivative (2c) gives the S-enantiomer with 75% ee whereas the hydrolysis of heptyl derivative (2d) results in the R-monoester with 90% ee. Chymotrypsin [9004-07-3] (CT) does not discriminate glutarates that have small substituents in the 3-position well. However, when hydroxyl is replaced by the much bulkier benzyl derivative (Ic), enantioselectivity improves significantly. 

Phthalic anhydride and diethyl phthalate are easily converted with hydrazine into 4-hydroxyphthalazin-l(2/f)-one. Its substituted derivatives have been prepared using substituted hydrazines, substituted phthalic anhydrides, or diesters or disodium salts of substituted phthalic acids (Scheme 81). However, condensation of phenylhydrazine with phthalic anhydride gives only a small amount of the corresponding phthalazine, the main product being 2-anilinophthalimide. This can be rearranged in the presence of base into the phthalazine derivative. For the preparation of 2,3-disubstituted derivatives, 1,2-disub-stituted hydrazines are reacted with the appropriate phthalic anhydrides or phthaloyl chlorides. Derivatives of 4-amino- or 4-hydrazino-phthalazin-l(2iT)-one have been prepared either from the corresponding monothiophthalimide and 3-aminoisoindolin-3-one (1S4) or from ethyl 2-cyanobenzoate (155) and hydrazine hydrate (Scheme 82). Similarly,... 

The ring-contracted analog of alphaprodine is prepared by a variation of the scheme above. Alkylation of 109 with ethyl bromoacetate affords the lower homolog diester (115). Dieckmann cyclization followed by saponification-decarboxylation yields the pyrrolidine (116). Reaction with phenylmagnesium bromide leads to the condensation product (117) acylation with propionic anhydride gives the analgesic agent prolidine (118)... 

The Hantsch pyridine synthesis provides the final step in the preparation of all dihydrop-yridines. This reaction consists in essence in the condensation of an aromatic aldehyde with an excess of an acetoacetate ester and ammonia. Tlie need to produce unsymmetrically subsrituted dihydropyridines led to the development of modifications on the synthesis. (The chirality in unsymmetrical compounds leads to marked enhancement in potency.) Methyl acetoacetate foniis an aldol product (30) with aldehyde 29 conjugate addition of ethyl acetoacetate would complete assembly of the carbon skeleton. Ammonia would provide the heterocyclic atom. Thus, application of this modified reaction affords the mixed diester felodipine 31 [8]. 

A solution of 88.5 parts of L-phenylalanine methyl ester hydrochloride in 100 parts of water is neutralized by the addition of dilute aqueous potassium bicarbonate, then is extracted with approximately 900 parts of ethyl acetate. The resulting organic solution is washed with water and dried over anhydrous magnesium sulfate. To that solution is then added 200 parts of N-benzyloxycarbonyl-L-aspartic acid-a-p-nitrophenyl, -benzyl diester, and that reaction mixture is kept at room temperature for about 24 hours, then at approximately 65°C for about 24 hours. The reaction mixture is cooled to room temperature, diluted with approximately 390 parts of cyclohexane, then cooled to approximately -18°C in order to complete crystallization. The resulting crystalline product is isolated by filtration and dried to afford -benzyl N-benzyloxycarbonvI-L-aspartyl-L-phenylalanine methyl ester, melting at about 118.5°-119.5°C. 

Maleic anhydride is also a precursor for 1,4-butanediol through an esterification route followed by hydrogenation. In this process, excess ethyl alcohol esterifies maleic anhydride to monoethyl maleate. In a second step, the monoester catalytically esterifies to the diester. Excess ethanol and water are then removed by distillation. The ethanol-water mixture is distilled to recover ethanol, which is recycled ... 

Hie reaction of a diamine with a diester under anhydrous conditions is reasonably rapid. However, a side reaction at high temperatures (>200°C) is N-substitution. Unfortunately, this N-substitution is particularly strong with methyl esters,28 37 65 and therefore, methyl esters such as dimediyl terephthalate or dimedryl isoph-thalate cannot be used for thermal polyamidations. Other esters, such as ethyl, butyl, and phenyl ester, do not seem to have this problem. 

Or 4-Furyl, thienyl, or selenienyljselenoamides on ethyl-a-chloro-a-ethoxalyl acetate as shown in Scheme 27. The diesters may be decar-boxylated by a saponification, an acid hydrolysis, and heating to 220CC successively (Scheme 27) (105). 

In this section primarily reductions of aldehydes, ketones, and esters with sodium, lithium, and potassium in the presence of TCS 14 are discussed closely related reductions with metals such as Zn, Mg, Mn, Sm, Ti, etc., in the presence of TCS 14 are described in Section 13.2. Treatment of ethyl isobutyrate with sodium in the presence of TCS 14 in toluene affords the O-silylated Riihlmann-acyloin-condensation product 1915, which can be readily desilylated to the free acyloin 1916 [119]. Further reactions of methyl or ethyl 1,2- or 1,4-dicarboxylates are discussed elsewhere [120-122]. The same reaction with trimethylsilyl isobutyrate affords the C,0-silylated alcohol 1917, in 72% yield, which is desilylated to 1918 [123] (Scheme 12.34). Likewise, reduction of the diesters 1919 affords the cyclized O-silylated acyloin products 1920 in high yields, which give on saponification the acyloins 1921 [119]. Whereas electroreduction on a Mg-electrode in the presence of MesSiCl 14 converts esters such as ethyl cyclohexane-carboxylate via 1922 and subsequent saponification into acyloins such as 1923 [124], electroreduction of esters such as ethyl cyclohexylcarboxylate using a Mg-electrode without Me3SiCl 14 yields 1,2-ketones such as 1924 [125] (Scheme 12.34). 

Alcohols can be phosphorylated to phosphoric diesters by ionic phosphoric monoimidazolides in acetone at temperatures of about 50-60 °C over the course of several hours. These imidazolides are generally prepared by reaction of the appropriate phosphate with CDI (see Section 2.2). Reactions with ethyl, -butyl, w-pentyl, -octyl benzyl alcohol and various other alcohols have also been described.[1]... 

Preparation of the quaternary anticholinergic agent benzilonium bromide (47) is begun by conjugate addition of ethylamine to methylacrylate, giving aminoester 42. Alkylation of 42 with methyl bromo-acetate leads to diester 43, which is transformed into pyrrolidone 44 by Dieckmann cyclization, followed by decarboxylation. Reduction of 44 by lithium aluminum hydride leads to the corresponding amino-alcohol (45). Transesterification of alcohol 45 with methyl benzilate leads to 46. Benzilonium bromide (47) is obtained by alkylation of ester 46 with ethyl bromide. 2... 

The phosphate diesters (02P(0R)2), ethyl-4-nitrophenyl phosphate and bis(4-nitrophenyl)phos-phate in c/.v-[(en)2Ir(OI I)(02P(0R)2]1, react intramolecularly with the as-OH group at pH 8 to liberate nitrophenolate.22... 

In contrast to ethyl diazoacetate, diethyl diazomalonate reacts with allyl bromide in the presence of Rh2(OAc)4 to give the ylide-derived diester favored by far over the cyclopropane (at 60 °C 93 7 ratio). This finding bespeaks the greater electrophilic selectivity of the carbenoid derived from ethyl diazomalonate. For reasons unknown, this property is not expressed, however, in the reaction with allyl chloride, as the carbenoids from both ethyl diazoacetate and diethyl diazomalonate exhibit a similarly high preference for cyclopropanation. 

---