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
The First International Dubrovnik NMR Course - Book of Abstracts / Vikić-Topić, Dražen ; Kovaček, Damir - Zagreb, 1999, 5-6

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 -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 -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 -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 -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

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