Preparations du Trans-P-Methoxyphenyl-1-propene-1-14C-3 (Trans Anethole 14C-3) et du trans-anethole (Noyau 14C-U)

✍ Scribed by Michel Herbert; Louis Pichat; Yves Langourieux

• Publisher: John Wiley and Sons
• Year: 1974
• Tongue: French
• Weight: 420 KB
• Volume: 10
• Category: Article
• ISSN: 0022-2135
• DOI: 10.1002/jlcr.2590100111

✦ Synopsis

Abstract

Methyl iodide ^14^C is reacted with lithium p‐methoxy phenylacetylenide to give with a 85% yield 1‐p‐methoxy‐phenyl‐1‐propyne‐3‐^14^C.

Reduction of the latter with LiAlH~4~ leads to a mixture of trans anethole‐3‐^14^C (85%) and cis anethole (15%) with a 55% yield. After preparative gas chromatography pure trans anethole‐3‐^14^C is isolated with an overall yield of 20% based on methyl iodide ^14^C.

Benzene ^14^C (U) is brominated into bromobenzene ^14^C (U) which by copper catalysed alcaline hydrolysis gives phenol ^14^C (U). Methylation of the latter leads to anisole ^14^C (U).

Gattermann reaction with the latter gives a mixture of o‐and p‐méthoxy‐benzaldehyde ^14^C (U) in a 80% yield from which pure para isomere is isolated by colwmn chromatography with a 42% yield based on anisole ^14^C (U). Treated with ethyl magensium iodide p‐methoxybenzaldehyde leads to 1‐p‐methoxy‐phenyl‐1‐propanol (ring ^14^C‐U) the dehydration of which by heating with Al~2~O~3~ gives a mixture of trans anethole (ring ^14^C‐U) (80%) and cis anethole (ring ^14^C‐U) (20%). After preparative gas chromatography pure trans anethole (ring ^14^C‐U) is isolated with an overall yield of 5% based on barium carbonate ^14^C.