GB1147888A - Process for the production of 4h-5,6-dihydro-1,3-oxazines - Google Patents

Abstract

1,147,888. 4H - 5,6 - Dihydro - 1,3 - oxazine derivatives. CHEMISCHE WERKE HœLS A.G. 4 May, 1966 [5 May, 1965], No. 19609/66. Heading C2C. In a process for the production of 4H-5,6- dihydro - 1,3 - oxazines a N - hydroxymethyl carbonamide is reacted with an olefinically unsaturated compound in the presence of a mineral acid, strong organic acid having a dissociation constant at room temperature greater than 10<SP>-2</SP> or Lewis acid, in at least equimolar amounts with reference to the 4H-5,6-1,3-oxazines to be formed. In examples: 2,6-diphenyl-#<SP>2</SP>-hydrooxazine is obtained by reacting N-hydroxymethylbenzamide with styrene in the presence of a mixture of sulphuric and acetic acids (1); 2-phenyl-6-vinyl-#<SP>2</SP>-hydro-oxazine is obtained similarly using butadiene instead of styrene (2); 2 - phenyl - 6,6 - dimethyl - #<SP>2</SP> - hydro-oxazine sulphate is obtained similarly using isobutylene instead of styrene (3); 2-vinyl-6,6-dimethyl-# 2 - hydro-oxazine is obtained by reacting acrylamide with formalin in presence of copper and reacting the product with isobutylene (6). Analogous processes yield 2,6,6-trimethyl-#<SP>2</SP>- hydro-oxazine; 2 - methyl - 6 - vinyl - #<SP>2</SP> - hydro-oxazine; 6,6 - dimethyl - #<SP>2</SP> - hydrooxazine; 2 - phenyl - 6 - acetoxy - #<SP>2</SP> - hydrooxazine; 2 - phenyl - 5,6 - tetramethylene - #<SP>2</SP> - hydro-oxazine and 6-phenyl-#<SP>2</SP>-hydro-oxazine. By-products include 1-methyl-3-benzamino-npropyl acetate; 2-methyl-4-acrylaminobutyl acetate and 1-phenyl-3-formaminopropanol-1.