Patent GB-1197479-A (GB)
Title: 3,1-Benzoxazine Derivatives and Process for their Manufacture
IPC: C07D265/18
Filed: 1967-11-20
Abstract: 1,197,479. 2-Amino-3,1-benzoxazine derivatives. FARBWERKE HOECHST A.G. 20 Nov., 1967 [24 Nov., 1966], No. 52643/67. Heading C2C. Novel compounds of general Formula I and acid addition salts thereof wherein R is H, alkyl, cycloalkyl, alkenyl, cycloalkenyl; aryl, aralkyl, or dialkylaminoalkyl in which the dialkylamino group may be cyclic and contain a further O or S atom or the N-atom may be substituted by a methyl or benzyl residue; R 1  is H, halogen, methoxy, CF 3  or NO 2 , R 2  and R 3  are each alkyl, cycloalkyl, aralkyl or aryl either optionally substituted in the aryl ring by halogen, methoxy, CF 3  or NO 2 , are prepared by one of the following methods: (a) a compound of Formula II wherein R 1  to R 3  are as above and X is Cl, Br, OH, alkoxy or alkanoyloxy, is reacted with an isocyanate of formula O=C=N-R or with a compound which forms such an isocyanate under the reaction conditions used, to give a compound of the general Formula I or a urea derivative of the compound of the general Formula II used as starting material, which urea derivative is then treated with an acid or a dehydrating agent to give a compound of the general Formula I; or (b) a compound of Formula IV wherein R 1  to R 3  and X have the above meanings, and A represents oxygen or sulphur, or a corresponding functional derivative of such a urea or thiourea, is treated with an acid or with a dehydrating agent when A stands for an oxygen atom, or, when A stands for a sulphur atom, is treated with a desulphurizing agent to give a compound of the general Formula I or a carbodiimide, which carbodiimide is subjected to simultaneous or subsequent acid treatment to give a compound of the general Formula I; or (c) a compound of the general Formula (II) above is reacted with a cyanogen halide of the general formula in which Y represents a chlorine, bromine or iodine atom, to give a compound of the general Formula I or a cyanamide, which cyanamide is then treated with an acid to give a compound of the general Formula I; or (d) a compound of Formula VI wherein R 1  to R 3  have the above meanings and R<SP>1</SP> is alkyl, alkenyl, aralkyl, halogenalkyl, or aryl radical or a lower dialkylaminoalkyl radical, in which latter the dialkylamino group may form a ring together with an oxygen or a sulphur atom or with an imino group which is substituted on the nitrogen by a methyl or benzyl group, is saponified or reduced with a complex metal hydride and, when R<SP>1</SP> represents a halogenalkyl radical, the compound (VI) is reacted, before or after reduction of the acyl group, with a dialkylamine which, as defined for R, may form a ring, and in all cases, if desired, a resulting basic compound is treated with an inorganic or organic acid to give a physiologically tolerable salt. Intermediates of general Formula IV above are prepared by reaction of a compound of Formula II above with an isocyanate or an isothiocyanate of formula R-N=C=A, where R and A have the above meanings. Intermediates of general Formula VI above are prepared either by acylation of the free amine or by cyclization and desulphurization of a compound of Formula IV above wherein R is acyl. Alcohols of Formula II above where X is OH, are prepared by reacting a suitably substituted anthranilic acid ester or a corresponding 2- aminophenylketone with a Grignard reagent. Pharmaceutical compositions in conventional forms for oral, rectal or parenteral administration and having analgesic, spasmolytic, tranquillizing, narcosis-prolonging and central nervous system depressive activity comprise an above novel compound of Formula I or a salt thereof and a carrier therefor.