A new look at acid catalyzed deacetylation of carbohydrates : A regioselective synthesis and reactivity of 2-O-acetyl aryl glycopyranosides

Abstract In the present work we report that acetyl groups of per – acetylated aryl glycosides have different reactivity during the acidic deacetylation using HCl/EtOH in CHCl3, which leads to preferential deacetylation at O-3, O-4 and O-6. Thereby, the one-step preparation of 2-O-acetyl aryl glycosides with simple aglycon was accomplished for the first time. It was proved that the found reagent is to be general and unique for the preparation of series of 2-О-acetyl aryl glycosides. We have determined the influence of both carbohydrate moiety and the aglycon on the selectivity of deacetylation reaction by kinetic experiments. Using DFT/B3LYP/6-31G(d,p) and semi-empirical АМ1 methods we have found that the highest activation barrier is for 2-О-acetyl group. This completely explains the least reactivity of 2-О-acetyl group.Peer reviewe

The first example of a one-step synthesis of 2'-O-acetyl aryl-D-glucopyranosides

A selective acidic system for partial deacetylation of phenolic d-glucopyranosides per-acetates has been developed that allows synthesis of the corresponding 2′-O-acetyl-d-glucosides. Many disadvantages of generally used methods for preparing such mono-acyl derivatives involving multistep procedures or the use of enzymes are avoided. The ion at m/z 289 in mass spectra of their TMS derivatives indicates a particular and characteristic fragmentation pattern of these 2′-O-acetyl derivatives of d-glucopyranosides. Quantum-chemical calculations applying B3LYP/TZVP level of theory revealed the stability of 2′-O-acetyl glucopyranoside if compare with 3′-, 4′- and 6′- O-acetyl glucopyanosides

The first example of a one-step synthesis of 2'-O-acetyl aryl-D-glucopyranosides

A selective acidic system for partial deacetylation of phenolic d-glucopyranosides per-acetates has been developed that allows synthesis of the corresponding 2′-O-acetyl-d-glucosides. Many disadvantages of generally used methods for preparing such mono-acyl derivatives involving multistep procedures or the use of enzymes are avoided. The ion at m/z 289 in mass spectra of their TMS derivatives indicates a particular and characteristic fragmentation pattern of these 2′-O-acetyl derivatives of d-glucopyranosides. Quantum-chemical calculations applying B3LYP/TZVP level of theory revealed the stability of 2′-O-acetyl glucopyranoside if compare with 3′-, 4′- and 6′- O-acetyl glucopyanosides

Design, synthesis and evaluation of a new Mn - contrast agent for MR imaging of myocardium based on the DTPA-phenylpentadecanoic acid complex

In the present paper we describe the first synthesis and evaluation of a novel Mn (II) complex (DTPA-PPDA Mn (II)) which contains a C-15 fatty acid moiety that has high affinity to the heart muscle. The complexation energy of DTPA-PPDA Mn (II) evaluated by quantum chemistry methodology indicates that it essentially exceeds the corresponding value for the known DTPA Mn (II) complex. Molecular docking revealed that the affinity of the designed complex to the heart-type transport protein H-FABP well exceeds that of lauric acid. Phantom experiments in low-field MRI the designed contrast agent provides MR imaging comparable to gadopentetic acid

Design, synthesis and evaluation of a new Mn - contrast agent for MR imaging of myocardium based on the DTPA-phenylpentadecanoic acid complex

In the present paper we describe the first synthesis and evaluation of a novel Mn (II) complex (DTPA-PPDA Mn (II)) which contains a C-15 fatty acid moiety that has high affinity to the heart muscle. The complexation energy of DTPA-PPDA Mn (II) evaluated by quantum chemistry methodology indicates that it essentially exceeds the corresponding value for the known DTPA Mn (II) complex. Molecular docking revealed that the affinity of the designed complex to the heart-type transport protein H-FABP well exceeds that of lauric acid. Phantom experiments in low-field MRI the designed contrast agent provides MR imaging comparable to gadopentetic acid

Determination of Impurities in Dibornol Substance by HPLC

Представлены результаты разработки методики и оценки ее пригодности (валидации) определения посторонних примесей в субстанции диборнола (4-метил-2,6-диизоборнилфенола) методом ВЭЖХ. Валидация проведена на этапе подготовки проекта фармакопейной статьи предприятия на субстанцию диборнола.The results of elaboration of procedure and suitability evaluation (validation) for the determination of impurities in dibornol (4-methyl-2,6-diisobornylphenol) substance have been presented. The validation was carried out at the stage of monographs of dibornol preparation

Determination of Impurities in Dibornol Substance by HPLC

Представлены результаты разработки методики и оценки ее пригодности (валидации) определения посторонних примесей в субстанции диборнола (4-метил-2,6-диизоборнилфенола) методом ВЭЖХ. Валидация проведена на этапе подготовки проекта фармакопейной статьи предприятия на субстанцию диборнола.The results of elaboration of procedure and suitability evaluation (validation) for the determination of impurities in dibornol (4-methyl-2,6-diisobornylphenol) substance have been presented. The validation was carried out at the stage of monographs of dibornol preparation