GB696471A - Process for the production of 3.6-dihydro-1.2 oxazines - Google Patents

Abstract

3,6 - Dihydro - 1,2 - oxazines of the general formula <FORM:0696471/IV (b)/1> wherein alkyl groups may be present attached to the carbon atoms of the ring and R represents a hydrocarbon radical, are prepared by reacting butadiene-1 : 3 or an alkyl-substituted butadiene-1 : 3 with a compound of the general formula RNO, where R has the above significance. In the examples: (1) N-phenyl-3,6-dihydro-1,2-oxazine is prepared and is then treated with hydrogen chloride or hydrogen bromide to give a chloro or bromo derivative in which the exact position of the chloro or bromo substituent in the ring is not known; (2) 1-phenyl-3 : 4-dimethyl-3 : 6-dihydro-1 : 2-oxazine is prepared. The Specification as open to inspection under Sect. 91 states that the products of the above process are pyrolline-oxides of the formula <FORM:0696471/IV (b)/2> which on being dehydrated yield substituted pyrroles <FORM:0696471/IV (b)/3> or the process may proceed direct to the pyrrole stage. 3 : 4-Oxido-pyrollidinium chloride is obtained by reacting butadiene-1 : 3 and 2-chloro-2-nitrosopropane (prepared by chlorinating acetoxime), and is converted to 3 : 3-oxidopyrrolidine with potassium hydroxide. This subject-matter does not appear in the Specification as accepted.