Ferf-butyl ester

Isobutyl chloroformate Formic acid, chloro-, isobutyl ester (8) Carbonochloridic acid, isobutyl ester (9) (543-27-1) S-tcrf-Butyl-L-cysteine ferf-butyl ester L-Cysteine, S-(l,l-dim-ethylethyl), 1,1-dimethylethyl ester (9) ( —) acetate (38024-19-0) hydrochloride (2481-11-0)... 

The application of 3-aminopropyl phosphine (3) [41,46] as a building block for incorporation into -COOH functionalized frameworks provides an excellent example of the utility of preformed primary phosphine frameworks (Scheme 8) [46]. The reactions involved Michael addition of ferf-butyl acrylate to malonic acid dimethyl ester to produce the intermediate adduct, 2-methoxycarbonyl-pentanedioc acid 5-ferf-butyl ester 1-methyl ester, which upon treatment with trifluro-acetic acid (TFA) produced the corresponding diester acid,2-methoxy-carbonyl-pentanedioic acid 1-methyl ester, in near quantitative yield. It is remarkable to note that the reaction of NH2(CH2)3PH2 (3) with the diester acid is highly selective as the -COOH group remained unattacked whereas the reaction occurred smoothly and selectively at the -COOMe groups to pro-... 

DI-ferf-BUTYL MALONATE (Malonic acid, di-ferf-butyl ester)... 

FIGURE 3.22 Protection (A) of carboxyl groups of amino acids as ferf-butyl esters,58 (B) of carboxyl groups of /V-substituted amino acids as fert-butyl esters,61 and (C) of phenolic and sulfhydryl groups as ethers. The amino acid esters are isolated as the hydrochlorides. 

Acetamidofluorene, see 2-Acetylaminofluorene 2-Acetaminofluorene, see 2-Acetylaminofluorene Acetanhydride, see Acetic anhydride Acetasol, see Acetic acid Acetdimethylamide, see A,A-Dimethylacetamide Acetic acid, amyl ester, see Amyl acetate Acetic acid anhydride, see Acetic anhydride Acetic acid (aqueous soln), see Acetic acid Acetic acid, 2-butoxy ester, see sec-Butyl acetate Acetic acid, butyl ester, see Butyl acetate Acetic acid, sec-butyl ester, see sec-Butyl acetate Acetic acid, ferf-butyl ester, see ferf-Butyl acetate Acetic acid dimethylamide, see A,A-Dimethylacetamide Acetic acid, 1,3-dimethylbutyl ester, see sec-Hexyl acetate Acetic acid, 1,1-dimethylethyl ester, see ferf-Butyl acetate Acetic acid, ethenyl ester, see Vinyl acetate... 

Carboxanilides, such as 359, are obtained from 335-type precursors (91MI1, 92MI1). Amidation of protected chiral educt 360 proceeds via coupling to protected aspartyl aldehyde synthon 361 followed by successive removal of the ferf-butyl ester and semicarbazone protecting groups to yield inhibitor 362 (98BML2757). 

A-Palmitoyl-S-f2,3-diliydroxy-(2f rS)-propyl]-(f )-cysteine ferf-Butyl Ester, Plm-Dhc-OtBu 90 ... 

P Anomer N-(9-Fluorenyhnethoxycarbonyl)-0-(3,4,6-tri-0-acetyl-2-azido-2-deoxy-P-D-galactopyranosyl)-L-threonine ferf-Butyl Ester yield, 115 mg (19%), [ot]D —8.0° (c 1, CHClj). 

IV-Benzyloxycarbonyl-Substituted Aminoacyl Hydroxy Add ferf-Butyl Esters General Procedure for the Synthesis of Protected Didepsipeptides Using Benzenesulfonyl Chloride 135 ... 

In 1959 Shchukina et a I. 56 showed that the addition of pyridine to DCC increases the yield (65-85%) of depsipeptides constructed from Z-protected amino acids and serine, threonine, or salicylic acid derivatives. The ferf-butyl ester of Af-(benzyloxycarbonyl)-leucylleucic acid (Table 2) was prepared in 60% yield under the same conditions of addition using a 2 molar excess of pyridine to carbodiimide. 57 The DCC/pyridine technique was successfully utilized in the ring closure between ()-alanine and leucic acid residues during the synthesis of the cyclic hexadepsipeptide destruxin B.[58 Under this modified approach the... 

V-f(Zi)-3- 2-[(rerf-Butyldiphenylsilyl)oxylethyl)-5-(methoxycarbonyl)-3-pentenyl]valine ferf-Butyl Ester (34) ... 

Exercise 15-11 A suitable method of preparing ferf-butyl esters is to add the carboxylic acid to 2-methylpropene. Good yields can be obtained if a strong acid catalyst is used, if water is excluded, and if the temperature is kept low ... 

Preparation of ferf-butyl esters from the acid and 2-methylpropene under pressure in... 

Additions of N-benzhydrylidene glycine ferf.-butyl ester (22, see Scheme 4.8) to alkyl acrylates ... 

As Scheme 68 illustrates, the first step of the reaction was the synthesis of the ferf-butyl ester 235 from bromoacetyl bromide 236. Owing to the... 

In a third microreactor, the anion of 4-ferf-butyl l-ethyl-2-(diethox-yphosphoryl)succinate was prepared in situ using sodium ethoxide 237 (in EtOH) and the Wittig-Horner olefination with benzaldehyde 116 performed using a residence time of 47 min to afford (E)-ferf-butyl-l-ethyl-2-benzylidenesuccinate 238 in excellent selectivity (89% yield). In a fourth reactor, the acid-catalyzed (TFA 239) ferf-butyl ester deprotection was achieved using a residence time of 5 min at 34 °C and employing DCM as the reaction solvent to afford (E)-3-(ethoxycarbonyl)-4-phenylbut-3-enoic acid 246 in 82% yield. The deprotection was subsequently followed by a Friedel-Crafts acylation, using triethylamine 14 and acetic anhydride 37, to afford 4-acetoxy-naphthalene-2-carboxylic acid ethyl ester 241 in quantitative yield when conducted at 130 °C (residence time = 47 min). 

Figure 3.53 shows an addition of a carboxybc acid to isobutene, which takes place via the tert-butyl cation. This reaction is a method for forming ferf-butyl esters. Because the acid shown in Figure 3.53 is a /i-hydroxycarboxylic acid whose alcohol group adds to an additional isobutene molecule, this also shows an addition of a primary alcohol to isobutene, which takes place via the ferf-butyl cation. Because neither an ordinary carboxylic acid nor, of course, an alcohol is sufficiently acidic to protonate the alkene to give a carbenium ion, catalytic amounts of a mineral or sulfonic acid are also required here. 

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