Synthesis and pharmacological investigation of new alkoxybenzamides—I

Synthesis and characterization of heterotelechelic poly(ethylene glycol)s with amino acid at one end and hydroxyl group at another end

“…20 On the other hand, the presence of protonic solvents such as ethanol, methanol, and water could enhance the reactivity of amino group but not that of hydroxyl group. 13,15,21 In our reaction system, the selected amino acid was derived to alkaline metal carboxylate by the addition of equal mole amount of inorganic alkali such as sodium hydroxide, and then the amino group of amino acid in free form in the alkaline reaction system could initiate the ring opening of ethylene oxide more effectively compared to the usual protonated form in neutral or acidic solution.…”

“…The 13 C NMR analyses of the obtained polymers were carried out with deuterated water as solvent. Figure 2(a-c) show the 13 C NMR spectra of the purified heterotelechelic PEGs ended with glycine, proline, and phenylala- 13 C NMR spectra of the amino acid ended heterotelechelic PEGs (Table I) nine, respectively. By referring to the literature on hydroxyl-terminated PEG and using glycine, proline, and phenylalanine as reference compounds, 23 the assignments of these signals were carried out, and the results were shown in Table I.…”

“…FT-IR transmission spectra were recorded on a JASCO FT-IR 660 spectrophotometer using 4 cm 21 resolution and 128 scans. 1 H NMR spectra and 13 C NMR spectra were recorded on an AVANCE Bruker spectrometer operating at 400.13, 100.61 MHz, respectively. Deuterated DMSO was used as the solvent for 1 H NMR spectroscopy and tetramethylsilane was used as an internal standard.…”

“…Deuterated DMSO was used as the solvent for 1 H NMR spectroscopy and tetramethylsilane was used as an internal standard. Deuterated water was used as the solvent for 13 C NMR. MS analyses were carried out on a LCQ Deca XP Thermo Finngian (San Jose, CA) ion trap MS equipped with an electrospray ionization source.…”

“…However, amino group showed great nucleophilic attack ability in the ring-opening reaction of epoxide compounds. [13][14][15][16][17][18][19][20] Micheloni et al synthesized bis(2-chloroethyl) pentylamine by the nucleophilic attack of pentylamine on ethylene oxide with ethanol as solvent. 14 Chakraborti et al have used montmorillonite K 10 to catalyze the ring opening of epoxides by amines under solvent-free conditions at room temperature and produced 2-amino alcohols.…”