2312
M. A. PASHA AND K. MANJULA
General Experimental Procedure for the Preparation of
4-Chlorobutyl Esters
Acyl chloride (10 mmol) and THF (10 ml) were taken in a 25-ml
round-bottomed flask. To this, magnesium turnings (0.024 g) were added and stirred
ꢀ
at 25 C. The progress of the reaction was monitored by thin-layer chromatography
(TLC); after completion of the reaction, the contents were filtered and washed with
ether (25 ml), and the organic layer was washed successively with saturated
NaHCO (10 ml), followed by water (3 ꢂ 10 ml), dried over anhydrous Na SO ,
3
2
4
concentrated, and purified by silica-gel column chromatography (5% ethyl acetate–
1
petroleum ether) to afford pure 4-chlorobutyl esters. The IR, H NMR, and LC-MS
spectral data of 4-chlorobutyl esters prepared by this procedure are presented.
Spectroscopic Data of the Products
ꢃ1
1
CH CO (CH ) Cl (3a). IR (neat) n ¼ 1739, 725 cm ; H NMR (400 MHz,
3
2
2 4
CDCl ) d: 1.78–1.87 (m, 4H), 2.04 (s, 3H), 3.55–3.58 (t, 2H, J ¼ 6 Hz), 4.06–4.11
3
þ
(
t, 2H, J ¼ 6 Hz); MS: m=z ¼ 151.0 (M ).
ꢃ1
1
C H CO (CH ) Cl (3b). IR (neat) n ¼ 1716, 711 cm ; H NMR (400 MHz,
6
5
2
2 4
CDCl ) d: 1.97 (m, 4H), 3.59 (t, 2H, J ¼ 4 Hz), 4.35 (t, 2H, J ¼ 4 Hz), 7.44 (d, 2H,
3
þ
J ¼ 8 Hz), 7.61 (t, 1H, J ¼ 8 Hz), 8.01 (d, 2H, J ¼ 8 Hz); MS: m=z ¼ 212 (M ).
ꢃ1
1
ClCH CO (CH ) Cl (3c). IR (neat) n ¼ 1751, 752 cm ; H NMR (400 MHz,
2
2
2 4
CDCl ) d: 1.65–1.93 (m, 4H), 2.07 (s, 2H), 3.61 (t, 2H, J¼ 6 Hz), 4.15 (t, 2H,
3
þ
J ¼ 6 Hz); MS: m=z ¼ 184 (M ).
ꢃ1
1
ClC H CO (CH ) Cl (3d). IR (neat) n ¼ 1720, 745 cm ; H NMR (400 MHz,
6
4
2
2 4
CDCl ) d: 1.93 (m, 4H), 3.65 (m, 2H), 4.38 (m, 2H), 7.67 (d, 2H, J ¼ 8 Hz) 7.89 (d,
3
þ
2
H, J ¼ 8 Hz); MS: m=z ¼ 246 (M ).
ꢃ1
1
BrC H CO (CH ) Cl (3e). IR (neat) n ¼ 1725, 743 cm ; H NMR (400 MHz,
6
4
2
2 4
CDCl ) d: 1.93 (m, 4H), 3.55 (m, 2H), 4.38 (m, 2H), 7.63 (d, 2H, J ¼ 8.4 Hz), 7.88 (d,
3
þ
2
H, J ¼ 8.5 Hz); MS: m=z ¼ 292 (M ).
ꢃ1
1
NO C H CO (CH ) Cl (3f). IR (neat) n ¼ 1745, 725 cm
;
H NMR
2
6
4
2
2 4
(
400 MHz, CDCl ) d: 1.92 (m, 4H), 3.65 (m, 2H), 4.36 (m, 2H), 7.52 (d, 2H,
3
þ
J ¼ 8 Hz), 7.96 (d, 2H, J ¼ 8 Hz); MS: m=z ¼ 257 (M ).
ꢃ1
1
C H CH=CHCO (CH ) Cl (3g). IR (neat) n ¼ 1768, 768 cm
;
H NMR
6
5
2
2 4
(
400 MHz, CDCl ) d: 1.93 (m, 4H), 3.65 (m, 2H), 4.38 (m, 2H), 6.42 (d, 1H,
3
J ¼ 16 Hz), 7.74 (d, 1H, J ¼ 16 Hz), 7.50 (d, 2H, J ¼ 8 Hz), 7.49 (t, 1H, J ¼ 8 Hz),
þ
7
.61 (d, 2H, J ¼ 8 Hz); MS: m=z ¼ 238 (M ).
CONCLUSION
In conclusion, we have presented a simple, efficient, economically viable, and
solvent-free protocol for the preparation of 4-chlorobutyl esters from THF and acyl
chlorides in the presence of catalytic amounts of nontoxic, readily available, and
inexpensive magnesium turnings. The advantageous of our method include a simple