Download (6Mb) - Etheses - Saurashtra University
Download (6Mb) - Etheses - Saurashtra University
Download (6Mb) - Etheses - Saurashtra University
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Chapter 1<br />
Synthesis of functionalized pyrimidines<br />
1.7 Experimental section<br />
Thin-layer chromatography was accomplished on 0.2-mm precoated plates of<br />
silica gel G60 F 254 (Merck). Visualization was made with UV light (254 and 365nm)<br />
or with an iodine vapor. IR spectra were recorded on a FTIR-8400 spectrophotometer<br />
using DRS prob. 1 H (300 MHz), 1 H (400 MHz), 13 C (75 MHz) and 13 C (100 MHz)<br />
NMR spectra were recorded on a Bruker AVANCE II spectrometer in CDCl 3 and<br />
DMSO. Chemical shifts are expressed in δ ppm downfield from TMS as an internal<br />
standard. Mass spectra were determined using direct inlet probe on a GCMS-QP 2010<br />
mass spectrometer (Shimadzu). Solvents were evaporated with a BUCHI rotary<br />
evaporator. Melting points were measured in open capillaries and are uncorrected.<br />
<br />
General synthetic procedure for the 3,4-dihydropyrimidine-2-(1H)-ones<br />
(ASM-01a-e).<br />
A 100mL round bottom flask equipped with magnetic stirrer and septum was<br />
charged with the methyl 4-methyl-3-oxopentanoate (0.01M), aldehyde (0.01M) and<br />
urea (0.015M). Few drops of DMF were added to the reaction mixture as a catalyst.<br />
The reaction mixture was then heated at 145-150 o C for 15-30 minutes. The progress<br />
of reaction was monitored by thin layer chromatography. The reaction mixture was<br />
allowed to cool at rt. Then, methanol (20 mL) was added and the resulting mixture<br />
was refluxed for 30 min. The solid separated upon cooling was filtered, washed with<br />
methanol and dried. The products thus obtained (ASM-01a-e) were directly used for<br />
the next step.<br />
<br />
General synthetic procedure for the 2-hydroxypyrimidine derivatives<br />
(ASM-02a-e).<br />
In a 100mL round bottom flask equipped with magnetic stirrer and<br />
thermometer was added nitric acid (60%) (10 mL). To the nitric acid slowly added<br />
ASM-01a-e (10 mmol) at 0 o C. After complete addition, the mixture was stirred at<br />
this temperature for 30 min. The progress of reaction was monitored by thin layer<br />
chromatography. The reaction mixture was poured into cold water and neutralized<br />
with saturated sodium bicarbonate solution. The solid separated was filtered, washed<br />
with water and dried. The crude products (ASM-02a-e) were directly used for the<br />
next step.<br />
Department of Chemistry, <strong>Saurashtra</strong> <strong>University</strong>, Rajkot-360005 25