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temperature and stand about 12 hrs, after which (0.12 mole) of acetyl acetone
added at one time. To the reaction mixture, 15 gm of zinc dust is added in
portions of about 2-3 gm with vigorous stirring. The rate of addition is regulated
so that temperature never rises above 60 o C. After the addition is complete, the
mixture is refluxed for 2-3 hrs on water bath until the unreacted zinc dust
collected in balls. The hot solution is then filtered and poured into ice water. The
creamy white product obtained is filtered and dried. Crude product is crystallized
from alcohol. M.P.-142-144 o C (reported M.P.-143 o C) A , Yield 45-60 %.
1.5.2 Preparation of (2E)-1-{5-[ethoxy (hydroxy) methyl]-2,4-dimethyl-1Hpyrrol-3-yl}-3-phenylprop-2-en-1-one
(Scheme-2)
General method:
In 100 ml conical flask, 1-{5-[ethoxy (hydroxy) methyl]-2,4-dimethyl-1H-pyrrol-3-
yl} ethanone (0.01 mole) and substituted aromatic aldehyde (0.01 mole) were
dissolved in chloroform. The catalytic amount of potassium hydroxide (2-3) drops
was added and the reaction mixture was refluxed for 2 hrs. The reaction progress
was monitored by TLC. After completetion of the reaction, chloroform was
distilled out completely and 10 ml methanol was added. Stirred for 20 min at 25-
30 o C. The product was filtered and dried in air oven. It was recrystallised from
methanol. Yield 50-60 %.
1.5.3 Preparation of [3, 5-dimethyl-4-(5-phenyl-4, 5-dihydro-1H-pyrazol-3-
yl)-1H-pyrrol-2-yl] (ethoxy) methanol (Scheme-3)
General method:
In 100 ml conical flask, 10 ml (0.32 mole) of hydrazine hydrate is added to the
solution of (2E)-1-{5-[ethoxy (hydroxy) methyl]-2,4-dimethyl-1H-pyrrol-3-yl}-3-
phenylprop-2-en-1-one (0.01 mole) in 20 ml ethanol and reflux with stirring in
water bath for 6-8 hrs. Pour the contain into crushed ice with stirring. The solid
obtained was filtered and washed with water. It was dried and recrystallized from
ethanol. Yield 65-70 %.
Physical data of the newly synthesized compounds are given in Table 1.6.
A Raval, K.; Ph.D. Thesis.; Saurashtra University, Rajkot, 2005.