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Chapter – 1 Preparation and Yield optimization.....
(efficient mechanical stirring was found to be extremely difficult if the mixture
was kept at room temperature during the addition of indole, and the yields of
indoline were only 5-15 %). After the addition to be completed stirring was
continued for 3-4 hours at 80°C under nitrogen. 100 ml water was added with
cooling and the mixture was basified slowly with 40% aqueous sodium
hydroxide. The thick slurry was steam distilled and the extraction of the
distillate with chloroform gave, after drying and concentration in vacuuo,
greenish oil. Distillation under reduced pressure gave 65 % of 2-methyl
indoline as slightly greenish transparent oil. BP – 224-226 °C (225-227°C d )
1.4.2 PREPARATION OF 2-METHYL INDOLINE MANNICH BASES
(1) GENERAL PROCEDURE FOR THE PREPARATION OF DNJ-101 TO
DNJ-111
It was prepared according to the method described by Abonia et. al. a
0.01 mole of 2-methyl indoline was charged into 50 ml erlenmeyer flask and
0.015 mole of formaldehyde (37-41% w/w solution) and 10 ml diethylether
were added into above flask and the mixture was magnetically stirred for
some time at room temperature under acidic condition. 0.01 mole of an
appropriate secondary amine was added drop wise into above reaction
mixture. Stirring was continued for further half an hour at room temperature.
The progress and the completion of the reaction were checked by silica gel-G
F254 thin layer chromatography using hexane : ethyl acetate (9 : 1) as a mobile
phase. After the reaction to be completed, the reaction mixture was extracted
using ethyl acetate (30 ml X 3). The combined organic layer was washed
using water (20 ml X 2). The organic layer was dried over anhydrous sodium
sulphate and the solvent was removed under reduced pressure to acquire the
product. (Physical data of the synthesized end products are summarized in
the table 1.5.1)
(2) GENERAL PROCEDURE FOR THE PREPARATION OF DNJ-201 TO
DNJ-210
It was prepared according to the method described by Abonia et. al. a
0.01 mole of 2-methyl indoline was charged into 50 ml erlenmeyer flask and
Department of Chemistry, Saurashtra University, Rajkot-360 005 42