| 摘要 |
<p>In a process for the preparation of a 2-chloroazacyclo-2, 3-alkene-N-carbochloride by reacting in the liquid phase the corresponding o -lactams with phosgene, the lactam being used (1) as such, and while ensuring that at all or substantially all times during the reaction there is an excess of the phosgene over the stoichiometric amount (i.e. a molar ratio of phosgene to lactam of more than 2:1), or (2) as the hydrochloric acid salt, the temperature is maintained at between 115 DEG to 150 DEG C. during at least the latter part of the reaction. The reaction temperature is preferably initially 25 DEG to 90 DEG C. and subsequently 115 DEG to 150 DEG C. Condition (1) may be maintained by feeding the lactam into phosgene or by feeding the phosgene and lactam simultaneously into a reaction vessel. Reaction pressures are preferably 10 to 50 atmospheres. Specification 901,169 also is referred to.</p> |
