Naslov
NMR Spectroscopic Investigation of Some Amino Acid Derivatives of B6 Vitamin

Autori
Jadrijević-Mladar Takač, Milena ; Vikić-Topić, Dražen, Rodighiero, Paolo

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts, The First International Dubrovnik NMR Course / Vikić-Topić, Dražen ; Kovaček, Damir - Zagreb : Institut Ruđer Bošković, 1999, 25-25

Skup
The First International Dubrovnik NMR Course

Mjesto i datum
Dubrovnik, Hrvatska, 27.06.1999. - 30.06.1999

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Amino Acid Ester; Pyridoxine; B6 Vitamin; NMR

Sažetak
Following our interest in the chemistry of B6 vitamin we have investigated the posibility of position-selective pyridoxine (B6) esterification with alpha-amino acids. The scope of investigation was the synthesis of the potential "pro drug" substances for the therapy of metabolic disorders that required an increased input of the corresponding essential alpha-amino acids (i.e., cirrhosis, hepatic encephalophaty, liver and renal failure).The method of transesterification in the case of 4', 5'-isobutyliden-pyridoxine, as an alcoholic moiety, using unprotected alpha-amino acid, p-toluensulfonic acid, and p-toluensulfochloride, proposed by Arai and Muramatsu failed. The only isolated product from the reaction mixture was 4', 5'-isobutiliden-pyridox-3O-yl-p-toluensulfonate. For this reason we used dicyclohexylcarbodiimide (DCC), a highly reactive, peptide copling reagent which usually gives good yields within a short time, and which is reagent of choice for the preparation of N-protected amino acid active esters. In this manner, esters of different, both, Boc- and Z-N-protected alpha-amino acids were synthesized. BOC-N-protected amino acids gave better yields in comparing to Z-amino acids, and the most reactive was BOC-Phe-OH. However, the 1H and 13C COM spectra showed that esterification products mostly exist as racemic mixtures, so we continued to study the chemical structures of obtained esters by FT-IR, one- and two-dimensional, homo- and heteronuclear 1H and 13C NMR correlation spectra (COSY, NOESY, HETCOR and HMBC). In these spectroscopic investigations the 4', 5'-isobutiliden-pyridox-3O-yl-p-toluensulfonate (1) and IBP-alanine ester (2) were used as model molecules and were helpful in the clarifying and distinguishing the 3H-[1, 3]dioxepino[5, 6c]pyridine moiety from amino acid part in the complex racemic mixture of synthesized esters. 4. M. Jadrijević-Mladar Takač, D. Vikić-Topić, and J. Vuković, Acta Pharm. 48 (1998) 145-153 ; Eur. J. Pharm. Sci. 6 (1988) S29. 5. I. Arai and I. Muramatsu, J. Org. Chem. 48 (1983) 121. 6. B. Castro, G. Evin, C. Selve, and R. Seyer, Synthesys, 1977, 413.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Farmacija

POVEZANOST RADA