Process for the preparation of 3-aryl-benzofuran-2-ones

A process for the preparation of compounds of formula I

• wherein, when n is 1,
• R1 is naphthyl, phenanthryl, anthryl, 5,6,7,8-tetrahydro-2-naphthyl, thienyl, benzo[b]thienyl, naphtho[2,3-b]thienyl, thianthrenyl, furyl, benzofuryl, isobenzofuryl, dibenzofuryl, xanthenyl, phenoxathiinyl, pyrrolyl, imidazolyl, pyrazolyl, pyrazinyl, pyridyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl, indolyl, indazolyl, purinyl, quinolizinyl, isoquinolyl, quinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, carbazolyl, β-carbolinyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl, isoxazolyl, furazanyl, biphenyl, terphenyl, fluorenyl or phenoxazinyl, each of which is unsubstituted or substituted by fluorine, hydroxy, C1-C18alkyl, C1-C18alkoxy, C1-C18alkylthio, di-(C1-C4alkyl)amino, phenyl, benzyl, benzoyl or by benzoyloxy or R1 is a radical of formula II or III
• when n is 2,
• R1 is phenylene or naphthylene each unsubstituted or substituted by C1-C4alkyl or by fluorine;
• or is —R6—X—R7—,
• R2, R3, R4 and R5 are each independently of the others hydrogen, fluorine, hydroxy, C1-C25-alkyl, C7-C9phenylalkyl, unsubstituted or C1-C4alkyl-substituted phenyl, unsubstituted or C1-C4alkyl-substituted C5-C8cycloalkyl;
• C1-C18alkoxy, C1-C18alkylthio, C1-C4alkylamino, di(C1-C4alkyl)amino, C1-C25alkanoyloxy, C1-C25alkanoylamino;
• C3-C25alkanoyloxy interrupted by oxygen, sulfur or by
• C6-C9cycloalkylcarbonyloxy, benzoyloxy or C1-C12alkyl-substituted benzoyloxy, or furthermore the radicals R2 and R3 or the radicals R3 and R4 or the radicals R4 and R5, together with the carbon atoms to which they are bonded, form a benzo ring, R4 is additionally —(CH2)p—COR9 or —(CH2)qOH or, when R3 and R5 are hydrogen, R4 is additionally a radical of formula IV
• wherein R1 is as defined above for the case where n=1,
• R6 and R7 are each independently of the other phenylene or naphthylene each unsubstituted or substituted by C1-C4alkyl,
• R8 is C1-C8alkyl,
• R9 is hydroxy, [ —O - ⁢ 1 r ⁢ M r + ] ,
• C1-C18alkoxy or
• R10 and R11 are each independently of the other hydrogen, CF3, C1-C12alkyl or phenyl, or R10 and R11, together with the carbon atom to which they are bonded, form a C5-C8cycloalkylidene ring unsubstituted or substituted by from 1 to 3 C1-C4alkyl groups;
• R12 and R13 are each independently of the other hydrogen or C1-C18alkyl,
• R14 is hydrogen or C1-C18alkyl,
• R19, R20, R21, R22 and R23 are each independently of the others hydrogen, halogen, fluoro-substituted C1-C12alkyl;
• —CN,
• —SOR46, —SO2R46, —SO3R46, —SO2R46, SO3R46, hydroxy, C1-C25alkyl;
• C2-C25alkyl interrupted by oxygen, sulfur or by
• C1-C25alkoxy;
• C2-C25alkoxy interrupted by oxygen, sulfur or by
• C1-C25alkylthio, C7-C9phenylalkyl, C7-C9phenylalkoxy, unsubstituted or C1-C4alkyl-substituted phenyl;
• unsubstituted or C1-C4alkyl-substituted phenoxy;
• unsubstituted or C1-C4alkyl-substituted C5-C8cycloalkyl;
• unsubstituted or C1-C4alkyl-substituted C5-C8cycloalkoxy;
• di(C1-C4alkyl)amino, C1-C25alkanoyl;
• C3-C25alkanoyl interrupted by oxygen, sulfur or by
• C1-C25alkanoyloxy;
• C3-C25alkanoyloxy interrupted by oxygen, sulfur or by
• C1-C25alkanoylamino, C6-C9cycloalkylcarbonyl, C6-C9cycloalkylcarbonyloxy, benzoyl or C1-C12alkyl-substituted benzoyl;
• benzoyloxy or C1-C12alkyl-substituted benzoyloxy;
• R24 is hydrogen, C1-C4alkyl, or unsubstituted or C1-C4alkyl-substituted phenyl,
• R25 and R26 are hydrogen, C1-C4alkyl or phenyl, with the proviso that at least one of the radicals R25 and R26 is hydrogen,
• R27 and R28 are each independently of the other hydrogen, C1-C4alkyl or phenyl,
• R29 is hydrogen or C1-C4alkyl,
• R30 is hydrogen, unsubstituted or C1-C4alkyl-substituted phenyl;
• C1-C25alkyl;
• C2-C25alkyl interrupted by oxygen, sulfur or by
• C7-C9phenylalkyl unsubstituted or substituted on the phenyl radical by from 1 to 3 C1-C4alkyl groups;
• or C7-C25phenylalkyl interrupted by oxygen, sulfur or by
• and unsubstituted or substituted on the phenyl radical by from 1 to 3 C1-C4alkyl groups,
• R31 is hydrogen or C1-C4alkyl,
• R32 is hydrogen, C1-C25alkanoyl;
• C3-C25alkanoyl interrupted by oxygen, sulfur or by
• C2-C25alkanoyl substituted by a di(C1-C6alkyl) phosphonate group;
• C6-C9-cycloalkylcarbonyl, thenoyl, furoyl, benzoyl or C1-C12alkyl-substituted benzoyl;
• R33 is hydrogen or C1-C8alkyl,
• R34 is a direct bond, C1-C18alkylene;
• C2-C18alkylene interrupted by oxygen, sulfur or by
• C2-C20alkylidene, C7-C20phenylalkylidene, C5-C8cycloalkylene, C7-C8bicycloalkylene, unsubstituted or C1-C4alkyl-substituted phenylene,
• R35 is hydroxy, [ —O - ⁢ 1 r ⁢ M r + ] ,
• C1-C18alkoxy or
• R36 is oxygen, —NH— or
• R37 is C1-C18alkyl or phenyl,
• R42 is hydrogen, hydroxy, [ —O - ⁢ 1 r ⁢ M r + ] ,
• C1-C25alkyl, C7-C9phenylalkyl, unsubstituted or C1-C4alkyl-substituted phenyl;
• unsubstituted or C1-C4alkyl-substituted C5-C8cycloalkyl;
• or C3-C25alkyl which is interrupted by oxygen, sulfur or
• R43 is C1-C25alkyl, C7-C9phenylalkyl, unsubstituted or C1-C4alkyl-substituted phenyl;
• unsubstituted or C1-C4alkyl-substituted C5-C8cycloalkyl;
• or C3-C25alkyl which is interrupted by oxygen, sulfur or
• R44 and R45 are each independently of one another hydrogen, C1-C25alkyl, hydroxyl-substituted C2-C24alkyl;
• C3-C25alkyl which is interrupted by oxygen, sulfur or
• C7-C9-phenylalkyl which is unsubstituted or is substituted on the phenyl ring by C1-C4alkyl;
• or C3-C24alkenyl;
• or R44 and R45, together with the nitrogen atom to which they are attached, form a 5-, 6- or 7-membered heterocyclic ring which is unsubstituted or is substituted by C1-C4alkyl or is interrupted by oxygen, sulfur or
• R46 is hydrogen or C1-C25alkyl,
• M is an r-valent metal cation,
• X is a direct bond, oxygen, sulfur or —NR14—,
• n is 1 or 2,
• p is 0, 1 or 2,
• q is 1, 2, 3, 4, 5 or 6,
• r is 1, 2 or 3, and
• s is 0, 1 or 2,
• which process comprises hydrolyzing a compound of formula V
• wherein
• R1 and n are as defined above,
• R2, R3, R′4 and R5 are each independently of the others hydrogen, fluorine, hydroxy, C1-C25alkyl, C7-C9phenylalkyl, unsubstituted or C1-C4alkyl-substituted phenyl, unsubstituted or C1-C4alkyl-substituted C5-C8-cycloalkyl;
• C1-C18alkoxy, C1-C18alkylthio, C1-C4alkylamino, di(C1-C4alkyl)amino, C1-C25alkanoyloxy, C1-C25alkanoylamino;
• C3-C25alkanoyloxy interrupted by oxygen, sulfur or by
• C6-C9cycloalkylcarbonyloxy, benzoyloxy or C1-C12alkyl-substituted benzoyloxy, or furthermore the radicals R2 and R3 or the radicals R3 and R′4 or the radicals R′4 and R5, together with the carbon atoms to which they are bonded, form a benzo ring, R′4 is additionally —(CH2)p—COR9 or —(CH2)qOH or, when R3 and R5 are hydrogen, R′4 is additionally a radical of formula VI
• wherein R1 is as defined above for the case where n=1,
• in an aqueous solvent in the presence of an acid.