الفهرس | Only 14 pages are availabe for public view |
Abstract The present thesis comprises three main parts : 1 - The frrst part is a general introduction on the chemistry of nucleosides , and a special introduction is devoted to discuss the synthesis of deazanucleosides . 2 - The second part is concerned with the results and discussion of the original work . 3 - Cyanopyridin - 2( 1H ) - thiones ( I11 a-r ) are synthesised and subjected to the cyclization to give thieno - [ 2 , 3 - b ] pyridine derivatives ( IV ) . a-e 2 - ( p - Chlorophenyl ) - 4 - phenyl - and 2- phenyl - 4 - fury1 - 5 - amino - 6 - benzoyl - thieno - [ 2 , 3 - b ] pyridines ( IV and IV ) are used as diazonium salt b d for the preparation of a new series of azo dyes ( V VI ) . a-f ’ a-e 3 - Cyanopyridin - 2( 1H) - thiones are used as starting materials for the coupling reactions with 2 , 3 , 4 , 6 - tetra - 0 - acetyl - a - D - gluco - and galactopyranosyl bromide in the presence of aqueous potassium hydroxide to give the corresponding I f 3 - cyano -1 - ( 2 ,3 ,4’, 6’ -tetra- 0-acetyl- P- D - gluco - andgalactopyranosyl ) pyridin - 2 - thiones ( VIII ) . a-r 1 - ( p - D - Gluco - and galactopyranosyl ) - 3 - cyanopyridin - 2 - thiones ( XI ) a-r were obtained in crystalline form by removing the blocking acetyl groups by treatment with methanolic ammonia . Compounds ( IIIa-r ) react with 2 . 3 , 4 - tri - 0 - acetyl - a - D - xylo - and p - L- arabinopyranosyl bromides in the presence of aqueous potassium hydroxide to give f I the corresponding 1 - ( 2 ,3 ,4’ - tri - 0 - acetyl - P - D - xylo - and P - L arabinopyranosyl) - 3 - cyanopyridin - 2 - thiones ( XI11 ) . Methanolysis of compounds a-k ( XIIIa-k ) give the corresponding 1- ( P - D- xylo - and fl - L - arabino-pyranosyl ) - 3 - cyanopyridin - 2 - thiones ( XV ) |