Process for preparing 2-oxo-dihydrobenzo(d)(1,3)-oxazines
AssigneeSterling Drug Inc.
InventorsJohn G. Thorpe, Peter G. Urben
Life of this patent
Estimating the term…
Abstract
A process for preparing 2-oxo-dihydrobenzo[d][1,3]oxazines (also named 1,4-dihydro-2H-3,1-benzoxazin-2-ones) which process comprises treating a suspension or solution of a 2-carbamoyl-benzyl alcohol in a substantially water-immiscible organic medium with aqueous alkaline hypochlorite or hypobromite having a pH of at least 11 in the presence of a phase transfer catalyst; and conversion of the 2-oxo-dihydrobenzo[d][1,3]oxazines to corresponding 2-amino-benzyl alcohols which are useful as intermediates in the production of dyes, pharmaceuticals and herbicides.
Claims31
A process for preparing a 2-oxo-dihydrobenzo[d][1,3]oxazine of the formula:
- ##STR4## wherein R.sup.4 represents hydrogen or a substituent selected from the group consisting of alkyl of 1 to 6 carbon atoms, phenyl and phenyl substituted by a substituent selected from the group consisting of alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, halo and nitro;
- R.sup.5 and R.sup.8, which can be the same or different, each represents hydrogen or a substituent selected from the group consisting of alkyl of 1 to 3 carbon atoms, alkoxy of 1 to 3 carbon atoms and halo;
- and R.sup.6 and R.sup.7, which can be the same or different, each represents hydrogen or a substituent selected from the group consisting of alkyl of 1 to 3 carbon atoms, alkoxy of 1 to 3 carbon atoms, halo and nitro;
- with the proviso that at least two of R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are hydrogen, which comprises suspending or dissolving in a substantially water-immiscible organic medium a 2-carbamoyl-benzyl alcohol of the formula:
- ##STR5## wherein R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are as defined above and treating the formed solution or suspension with an aqueous alkaline solution of a hypochlorite and/or hypobromite having a pH of at least 11 in the presence of a phase transfer catalyst to obtain the compound of formula I.
Dependencies are inferred from the claim text.