title: The first proton sponge-based amino acids: synthesis, acid-base properties and some reactivity.
abstract: The first hybrid base constructed from 1,8-bis(dimethylamino)naphthalene (proton sponge or DMAN) and glycine, N-methyl-N-(8-dimethylamino-1-naphthyl)aminoacetic acid, was synthesised in high yield and its hydrobromide was structurally characterised and used to determine the acid-base properties via potentiometric titration. It was found that the basic strength of the DMAN-glycine base (pKa = 11.57, H2O) is on the level of amidine amino acids like arginine and creatine and its structure, zwitterionic vs. neutral, based on the spectroscopic (IR, NMR, mass) and theoretical (DFT) approaches has a strong preference to the zwitterionic form. Unlike glycine, the DMAN-glycine zwitterion is N-chiral and is hydrolytically cleaved with the loss of glycolic acid on heating in DMSO. This reaction together with the mild decarboxylative conversion of proton sponge-based amino acids into 2,3-dihydroperimidinium salts under air-oxygen was monitored with the help of the DMAN-alanine amino acid. The newly devised amino acids are unique as they combine fluorescence, strongly basic and redox-active properties.
authors.affiliation: Department of Organic Chemistry, Southern Federal University, Zorge str. 7, 344090 Rostov-on-Don, Russian Federation. vv_ozer2@sfedu.ru.
authors.forename: Valery A
authors.initials: VA
authors.lastname: Ozeryanskii
authors.forename: Anastasia Yu
authors.initials: AY
authors.lastname: Gorbacheva
authors.forename: Alexander F
authors.initials: AF
authors.lastname: Pozharskii
authors.forename: Marina P
authors.initials: MP
authors.lastname: Vlasenko
authors.forename: Alexander Yu
authors.initials: AY
authors.lastname: Tereznikov
authors.forename: Margarita S
authors.initials: MS
authors.lastname: Chernov'yants
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry*; D060326:Chemistry Techniques, Synthetic; D006868:Hydrolysis; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D011522:Protons; D011789:Quantum Theory; D013696:Temperature
chemical_list: D000596:Amino Acids; D011522:Protons