Abstract: The invention relates to new derivatives of 3-oxo-2,3-dihydro-1,4-benzoxazine corresponding to the general formula ##SPC1##In whichR.sub.1 is selected from the group consisting of the hydrogen atom and a lower alkyl group;R.sub.2, r.sub.3 and R.sub.4 which are identical or different, are selected from the group consisting of the hydrogen atom, a halogen atom, a nitro group, a lower alkyl group, a lower alkoxy group and R.sub.4 may be an allyl group;R.sub.5 is selected from the group consisting of the hydrogen atom and an acyl group, preferably acetyl. These derivatives can be used for therapeutic purposes, more especially as analgesics and anti-oedematous agents.