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Chapter – 4 Studies on different types of reactions…..
4.9.7 GENERAL PROCEDURE FOR THE PREPARATION OF DNJ-1601
TO DNJ-1605 AND DNJ-1701 TO DNJ-1705
0.015 mole of urea / thiourea was dissolved into 20 ml of methanol.
0.01 mole of an appropriately substituted pyrazole-4-carboxaldehyde was
added to above reaction mixture and additional 20 ml of methanol was added
along with few drops of concentrated hydrochloric acid. This reaction mixture
was transferred to 250 ml round bottom flask containing 0.01 mole of 4hydroxycoumarin
into 10 ml of methanol. The content of the flask was heated
on water bath for 5-6 hours. The progress and the completion of the reaction
were checked by silica gel-G F254 thin layer chromatography using toluene :
ethyl acetate (7 : 3) as a mobile phase. After the reaction to be completed, the
reaction mixture was cooled to room temperature and the product was
separated by filtration. The product was washed with methanol and dried to
give desired product in moderate yield which was recrystallized by DMF.
(Physical data of the synthesized end products are summarized in the table
4.10.4 & 4.10.5)
Department of Chemistry, Saurashtra University, Rajkot – 360 005 229