2- aminoethyl ester

Aminoethanolato-lA,0)diphenylboron, lOCI. Diphenylborinic acid 2-aminoethyl ester. Aminoethyl diphenylborinate. Hydroxydiphenylborane ethanolamine [15614-89-8]... 

One of the virtues of the Fischer indole synthesis is that it can frequently be used to prepare indoles having functionalized substituents. This versatility extends beyond the range of very stable substituents such as alkoxy and halogens and includes esters, amides and hydroxy substituents. Table 7.3 gives some examples. These include cases of introduction of 3-acetic acid, 3-acetamide, 3-(2-aminoethyl)- and 3-(2-hydroxyethyl)- side-chains, all of which are of special importance in the preparation of biologically active indole derivatives. Entry 11 is an efficient synthesis of the non-steroidal anti-inflammatory drug indomethacin. A noteworthy feature of the reaction is the... 

Aminoethyl hydrogen sulfate (sulfuric acid mono-2-aminoethyI ester) [926-39-6] M 141.1, m 285-287 (chars at 275 ). Crystd from water or dissolved in water and EtOH added. 

Dipping solution Dissolve 1 g diphenylboric acid-2-aminoethyl ester (diphenylboric acid / -aminoethyl ester, diphenylboryloxyethylamine, Naturstoffreagenz A , Flavognost ) in 100 ml methanol. 

Diphenylboric acid-2-aminoethyl ester reacts to form complexes with 3-hydroxy-flavones with bathochromic shift of their absorption maximum. 

The Bsmoc derivative is formed from the chloroformate or the A -hydroxy-succinimide ester. It is cleaved rapidly by a Michael addition with tris(2-aminoethyl)amine at a rate that leaves Fmoc derivatives intact. More hindered bases, such as A -methylcyclohexylamine or diisopropylamine, do not react with the Bsmoc group, but do cleave the Fmoc group, illustrating the importance of steric effects in additions to Michael acceptors. 

The Wenker aziridine synthesis entails the treatment of a P-amino alcohol 1 with sulfuric acid to give P-aminoethyl sulfate ester 2 which is subsequently treated with base to afford aziridine 3. Before the discovery of the Mitsunobu reaction, wbicb transforms an amino alcohol into an aziridine in one step under very mild conditions, the Wenker reaction was one of the most convenient methods for aziridine synthesis. However, due to the involvement of strong acid and then strong base, its utility has been limited to substrates without labile functionalities. 

In 1935, Wenker" first prepared P-aminoethyl sulfate ester (4, a solid) from thermal dehydration of monoethanolamine acid sulfate at 250°C according to Gabriel s procedure." Subsequently, the mixture of 4 and 40% NaOH aqueous solution was distilled. Further fractional distillation of the distillate in the presence of KOH and then Na at 55-56 C led to pure aziridine in 26.5% yield. 

Due to the convenience of the Wenker aziridine formation from P-aminoethyl sulfate ester (4) and base, many improvements ensued. Leighton et al. improved the yield of the first step for the formation of sulfate ester 4. First of all, both ethanolamine and 95% sulfuric acid were diluted with half of their weight of water and then slowly mixed together at 0 C. Finally, by keeping the temperature below 145 C, sulfate ester 4 was obtained in 90-95% yield. 

Reaction with dimethylethylamine instead of methylethylamine leads directly to a quaternary compound, which type of compound can also be obtained by reacting the tertiary aminoethyl ether with reactive esters. 

Methyl-isoxazole-(3)-carboxylic acid chloride 4-(/3-Aminoethyl)benzene sulfonamide hydrochloride Chloroformic acid methyl ester N-Amlno-hexamethylene imine... 

There is obtained from 4-[)3-[5-methyl-isoxazolyl-(3)-carboxamido]-ethyl]-benzene-sulfonamide (prepared from 5-methyl-isoxazole-(3)-carboxylic acid chloride and 4-()3-aminoethyl)-benzene-sulfonamide hydrochloride, MP 213° to 214°C in pyridine) and chloroformic acid methyl ester, in a yield of 69%, the compound N-[ [-4-[)3-[5-methyl-isoxazolyl-(3)-carbox-amido] -ethyl] ] -benzene-sulfonyl] ] -methyl-urethane in the form of colorless crystals of MP 173°C. 

Diphenylamine la 179 lb Dipheny Iboric acid 2-aminoethyl ester la 277... 

Diphenylamine reagent 179 Diphenylboric acid-2-aminoethyl ester reagent 277... 

Reactions with dialdehydes allow the introduction of two additional rings in one step. Thus, condensation of 1 -(2-aminoethyl)pyrrole with glutaraldehyde and benzotriazole gives tricyclic intermediate 627 in which the benzotriazolyl moiety can be readily substituted with nucleophiles to give products 628 (Scheme 97) <2002JOC8220>. Condensation of ethyl ester of L-tryptophan with 2,5-dimethoxytetrahydrofuran and benzotriazole in acetic acid gives tetracyclic intermediate 629 which upon treatment with nucleophiles (silyl derivatives) is converted to products 630 <1999T3489>. 

Severin and coworkers reported (146) the reaction of tris(2-aminoethyl)amine and 4-formylphenylboronic acid with penta-erythritol to give, via multicomponent assembly, the boronic acid based macrobicyclic cage 35 (Fig. 25). The cage has the form of an ellipsoid with a diameter of 20.5 A and binds two Cud) ions in a fashion similar to the smaller tren-based cryptands. The reversible formation of boronic esters has also been employed to build other hollow structures such as nanotubes (147) and porous covalent organic frameworks (148,149). 

Aminoethyl)piperidine (16) is a base and nucleophile employed for removal of fluorenylmethyl-based protectors during synthesis in solution. The adduct formed with the released moiety can be separated from the peptide ester by extraction into a pH 7.4 phosphate buffer (see Section 7.11). 

A well-designed series of AA-disubstituted 2-aminoethyl and 3-amino-propyl esters of indomethacin (8.9, R = OH) was examined for its chemical and enzymatic (human plasma) rates of hydrolysis [40]. The 3-(diethylami-no)propyl ester had a transcutaneous permeability coefficient ca. 100-times... 

Peptide derivatives of the bisindole alkaloids have been prepared by appending amino acids at C-3. Reaction of acylazide 62 with an ct-amino acid ester affords amide derivatives of this type (122) (46). Conversely, the attachment of the amino acid can be inverted by reacting a C-3 amide derivative with an activated amino acid ester. Thus, treatment of 3-0-aminoethyl)-4-deacetylvinblastine amide (70) with an N-protected a-ami-noacylazide gives the alternative amide derivative (123). These techniques have been used to prepare di-, tri-, and tetrapeptide conjugates. 

Nicardipine Nicardipine, l,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-methyl-2-[(methyl-phenylmethyl)-amino]ethyl ester 3,5-pirididincarboxylic acid (19.3.7), is synthesized in a manner analogous to the synthesis of nifedipine, the only difference being that in the Hantsch synthesis, two different )3-dicarbonyl compounds are used simultaneously with o-nitrobenzaldehyde. During this, one of these in the enamine form of acetoacetic ester is simultaneously used as an amine component. A heterocycUzation reaction is accomplished by reacting, the methyl ester of 8-aminocrotonic acid with the 2-methyl-2-benzyl-aminoethyl ester of acetoacetic acid [24-27]. 

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