Synthesis of some new branched nucleoside analogues at (C-3`)‎ and study their effect on the alkaline phosphatase isoenzymes activity

Other Title(s)

تحضير بعض مماثلات النيوكليوسيد الجديدة المتفرعة عند (C-3`)‎ و دراسة تأثيرها على فعالية متناظرات إنزيم الفوسفاتيز القاعدي

Dissertant

al-Asadi, Ahmad Wahid Nasir

Thesis advisor

Hasan, Hadhamh Razzuqi
al-Fattahi, Yusuf Ali

University

University of Baghdad

Faculty

College of Science

Department

Chemistry Department

University Country

Iraq

Degree

Ph.D.

Degree Date

2007

English Abstract

Throughout this work, four types of new nucleoside analogues have been synthesized.

1: 3`,3`-di-C-nitromethyl nucleoside analogues.

2: 3`-C-dicyanomethyl-3`-C-nitromethyl nucleoside analogues.

3: 3`,3`-di-C-bis-cyanomethyl nucleoside analogues.

4: 3`-C-nitromethyl-3`-C-dicyanomethyl nucleoside analogues.

To prepare these nucleosides, the compound 1,2:5,6-di-Oisopropylidene- a-D-glucofuranose have been chosen as a starting material which contains a free OH group as C3.

This compound upon oxidation with dimethyl sulfoxide and acetic anhydride afforded, the keto sugar (3).

The key steps used to prepare the nucleoside analogues involve the following:- 1: a- The first and second types of the nucleoside analogues were prepared by the reaction of keto sugar with nitromethane in either the presence of 0.1 molar equivalents of sodium tetr-butoxide, or under phase transfer catalysis (PTC).

Either of these two procedures produced compound (4), which when compound (4) was treated with excess of nitromethane or malononitrile in the presence of sodium methoxide gave 3,3-di-C-nitromethyl (5) and 3-C-dicyanomethyl-3-C-nitromethyl (6) derivatives respectively.

b- To prepare the third and fourth nucleoside analogues, the keto sugar was reacted with malononitrile under the same above mentioned conditions to give derivative (15).

Addition of excess malononitrile or nitromethane in basic media produced 3,3-di-C-bis-cynaomethyl (17) and 3-C-nitromethyl-3-C-dicyanomethyl (16) derivatives respectively.

XI 2- The above mentioned treatments were followed by a selective hydrolysis of the 5,6-isopropylidene group using 60% acetic acid.

3- In order to protect the hydroxyl groups in the position 5 and 6, acetic anhydride and dry pyridine were used to give (9, 10, 20 and 21) derivatives.

4- In order to obtain the branched sugars (11, 12, 22 and 23), exchange of the 1,2-isopropylidene group for two acetyl groups was carried out using concentrated acetic acid, acetic anhydride and concentrated sulphuric acid.

5- To prepare the protected nucleoside analogues (26, 27, 28, 29, 34, 35, 36 and 37), the branched sugars were treated with 50% hydrogen bromide in acetic acid, followed by coupling reaction with theophylline and indol mercuric salts using Konigs-Knorr method.

6- The last stage involves hydrolysis of acetyl groups to prepare unprotected nucleoside analogues (30, 31, 32, 33, 38, 39, 40 and 41) using sodium methoxide.

The unprotected nucleoside analogues were identified by FTIR, U.V.

and 1HNMR spectrum.

The second part of the current work includes studying the effect of the prepared nucleoside analogues on the alkaline phosphatase (ALP) isoenzymes activity throughout:- 1- Measuring the ALP enzyme activity in the sera of healthy individuals using Kind-King method.

This method is based on the liberation of phenol from phenylphosphate which was used as a substrate at pH 10.

The librated phenol was determined colorimetrically at l = 510nm.

XII 2- Studying the effect of the prepared nucleoside analogues (30, 31, 32, 33, 38, 39, 40 and 41) on the alkaline phosphatase isoenzymes activities was performed, using electrophoresis technique.

This was carried out where 5% acrylamide gel and Tris-borate pH 9.5 were used as separating matrix and buffers separation respectively.

To localize the enzyme activity bands, a- naphthylphosphate as a substrate and fast blue BB were used.

The prepared nucleoside analogues (0.03 M) exhibited inhibitions effect on the liver and bone isoenzymes simultaneously.

Heat inhibition method (15 minutes at 56°C) was used to distinguish between the activity of liver and bone isoenzymes, after which the effect of the prepared nucleoside derivatives were tested.

The results indicated that these analogues had an inhibitory effect on the liver isoenzyme only.

Main Subjects

Chemistry

Topics

• Enzymes
• Blood plasma

No. of Pages

143

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-600138