Patent EA-005006-B1 (EA)
Title: Method for producing aryl-iminomethyl-carbamic acid esters
Inventor: BRANDENBURG JORG
IPC: C07C271/00
Filed: 2001-01-11
Abstract: 1. Process for preparing compounds of formula (I) wherein R<1> denotes a group selected from among methyl, ethyl, propyl, cyclopentyl, cyclohexyl, phenyl, benzyl and -C(Me2)phenyl, each of which may be mono-, di- or trisubstituted by hydroxy; R<2> denotes a group selected from among methyl, ethyl, propyl and benzyl, characterised in that a compound of formula (II) wherein R<1>' denotes a group selected from among methyl, ethyl, propyl, cyclopentyl, cyclohexyl, phenyl, benzyl and -C(Me2)phenyl, each of which may be mono-, di- or trisubstituted by a group -O-PG, the group -O-PG denoting a protected hydroxyl function selected from among methoxymethyloxy, 2methoxyethoxymethyloxy, 1-ethoxyethyloxy, 2-tetrahydropyranyloxy, 1-butoxyethyloxy, tertbutyloxy, benzyloxy and 4-methoxybenzyloxy, is first reacted in an ethereal or aromatic solvent with an alkali metal hexaalkyldisilazane and is then treated with a compound of formula (III) R<2>-O-COX' (III) wherein R<2> is as hereinbefore defined and X' denotes chlorine, bromine or -O-R<2>, after working up using an acid of formula HY a compound of formula (IV) and/or the tautomeric form thereof wherein the groups R<1> and R<2> are as hereinbefore defined and Y denotes any desired acid group, is isolated and from this the compound of formula (I) is liberated. 2. Process according to claim 1, wherein R<1> denotes a group selected from among phenyl, benzyl and -C(Me2)phenyl, each of which may be mono- or disubstituted by hydroxy; R<2> denotes a group selected from among ethyl, propyl and benzyl, characterised in that a compound of formula (II) wherein R<1>' denotes a group selected from among phenyl, benzyl and -C(Me2)phenyl, each of which may be mono- or disubstituted by a group -O-PG, the group -O-PG denoting a protected hydroxyl function selected from among methoxymethyloxy, 2-methoxyethoxymethyloxy, 1-ethoxyethyloxy, 2-tetrahydropyranyloxy, 1-butoxyethyloxy, tertbutyloxy, benzyloxy and 4-methoxybenzyloxy, is first reacted in an ethereal or aromatic solvent with an alkali metal hexaalkyldisilazane and then treated with a compound of formula (III) Wherein R<2> is as hereinbefore defined and X' denotes chlorine, bromine or -O-R<2>, after working up with aqueous hydrochloric acid a compound of formula (IVA) wherein the groups R<1> and R<2> are as hereinbefore defined is isolated and from this the compound of formula (I) is liberated. 3. Process according to claim 1 or 2, wherein R<1> denotes -C(Me2)phenyl which may optionally be monosubstituted by hydroxy and R<2> denotes ethyl, characterised in that a compound of general formula (II) wherein R<1>' denotes -C(Me2)phenyl, which may optionally be monosubstituted by a group -O-PG, the group -O-PG denoting a protected hydroxyl function selected from among methoxymethyloxy, 2-tetrahydropyranyloxy, 1-butoxyethyloxy, tertbutyloxy, benzyloxy and 4-methoxybenzyloxy, is first reacted in an ethereal or aromatic solvent with an alkali metal hexaalkyldisilazane and then treated with a compound of formula (III) R<2>-O-COX' (III) wherein R<2> is as hereinbefore defined and X' denotes chlorine, bromine or -O-R<2>, after working up using an acid of formula HX a compound of formula (IV) is isolated wherein the groups Y, R<1> and R<2> are as hereinbefore defined and from this the compound of formula (I) is liberated. 4. Process for preparing a compound of formula I according to one of claims 1 to 3, characterised by the following steps: (e) reacting C1-4 -alkyl 3-halomethylbenzoates with 4-hydroxybenzonitrile in the manner of a Wilkinson ether synthesis; (f) reductively converting alkyl 3-(4-cyano-phenoxy)benzoates of formula (VII) wherein R' denotes C1-4-alkyl, into a compound of formula (V) wherein X denotes hydroxy; (g) optionally treating the compound of formula (V) wherein X denotes hydroxy with a halogenating reagent or a sulphonic acid chloride; (h) reacting the compound of formula (V) wherein X denotes hydroxy, chlorine, bromine, mesylate, triflate or tosylate, with a phenol derivative of formula (VI) wherein R<1>' has the meanings given in claims 1 to 3; optionally in the form of the corresponding sodium or potassium phenoxides, under basic reaction conditions, in a polar organic solvent; (i) converting the resulting compound of formula (II) into the compound of formula (I) using the method according to claims 1 to 3. 5. Intermediate products of formula (IVA) and/or the tautomeric form thereof wherein the groups R<1> and R<2> may have the meanings given in claims 1, 2 or 3. 6. Intermediate products of general formula (V) wherein X denotes hydroxy, chlorine, bromine, mesylate, triflate or tosylate. 7. Intermediate products according to claim 6, wherein X denotes hydroxy or chlorine. 8. Intermediate products of general formula (VII) wherein R<1> denotes C1-4alkyl. 9. Use of the intermediate products of general formula (IV) according to claim 5 for preparing a compound of formula (I) according to claim 1. 10. Use of the intermediate products of general formula (V) according to claim 6 or 7 for preparing a compound of formula (I) according to claim 1. 11. Use of the intermediate products of general formula (VII) according to claim 8 for preparing a compound of formula (I) according to claim 1.