Condensation of propionyl chloride with paraformaldehyde in presence of Lewis acid; chloromethyl propionate
SyntheticPage 289
DOI:
10.1039/SP289
Submitted Jun 27, 2008, published Jun 27, 2008
Chemicals Used
Propionyl chloride (Aldrich), paraformaldehyde (Qualigens), Zinc Chloride (Rankem)
Procedure
A mixture of propionyl chloride (1.0 g, 10.8 mmol, 1 eq.), paraformaldehyde (0.36 g, 11.8 mmol) stirred at room temperature and catalytic amount of anhydrous zinc chloride (Lewis acid) (0.147 g, 1.08 mmol) was added. After 30 min of addition reaction mixture was heated at 100-110°C for 7 h. The crude product distilled at b.p. 55-60°C /40 mmHg to yield pure product chloromethyl propionate as a colorless liquid (0.9 g, 68%).
Author's Comments
The reaction proceeds in presence of anhydrous Zinc chloride giving good yields (62-92%).
If the Zinc chloride with moisture content is used in the reaction, will give poor yield.
We have carried out the reaction using Acetyl chloride (Y = 92.1%), n-valeryl chloride (Y= 68.0%) and isovaleryl chloride (Y = 70.3%).
Data
1H NMR (300MHz, CDCl3):1.13-1.20 (t, 3H, CH3), 2.35-2.44 (q, 2H, CH2), 5.8 (S, 2H, ClCH2O); MS (ES-) m/z (relative intensity) 121.3 (M+H) (100).
Lead Reference
Y. Yoshimura, N. Hamaguchi,T.Yashiki; US 4,497,809.
Other References
A. Marfat, D. G. McLeod; US 7,091,197.
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Keywords: Zinc chloride, substitution, esters
