Patent GB-1447583-A (GB)
Title: Xanthene derivatives
IPC: C07D491/107
Filed: 1974-02-04
Abstract: 1447583 Xanthene - 9 - spiro - 4<SP>1</SP> - piperidines IMPERIAL CHEMICAL INDUSTRIES Ltd 30 Dec 1974 [4 Feb 1974] 05016/74 Heading C2C [Also in Division A5] Novel xanthene-9-spiro-4<SP>1</SP>-piperidines of the general formula wherein R<SP>1</SP> is a hydrogen atom or a C 1-10  alkyl, C 3-10  alkenyl, C 3-6  haloalkenyl, C 3-6  alkynyl, C 4-7  cycloalkylalkyl(optionally substituted in the cycloalkyl nucleus by a C 6-10  aryl group or by one or two C 1-3  alkyl groups), phenyl, C 7-10  arylalkyl (optionally substituted in the aryl group by one to three halogen atoms or C 1-3  alkyl groups), C 8-12 aroylalkyl (optionally substituted in the aryl group by one to three halogen atoms or C 1-3  alkyl groups), C 2-5  hydroxyalkyl, C 4-8  dialkylaminoalkyl, C 2-8  carbamoylalkyl, C 3-8  alkylcarbamoylalkyl, C 4-8  dialkylcarbamoylalkyl or C 3-8 alkanoylalkyl group and each of R<SP>2</SP>, R<SP>3</SP>, R<SP>4</SP> and R<SP>6</SP> is a hydrogen or halogen atom or a C 1-5  alkyl, C 1-5  haloalkyl, C 1-5  alkoxy, C 1-5  alkylthio, hydroxyl, thiol, C 1-5  alkanoylamino, C 1-5 alkanoyloxy, C 7-10  aroyloxy (optionally substituted in the aryl group by one to three halogen atoms or C 1-3  alkyl groups), C 9-12  arylalkenoyloxy, C 1-5  hydroxyalkyl, C 1-5  alkylsulphinyl or C 1-5  alkanesulphonyloxy group, and pharmaceutically acceptable acid addition salts thereof are prepared by standard methods. 1<SP>1</SP> - Methylxanthene - 9 - spiro - 4<SP>1</SP> - piperidin- 2<SP>1</SP>-one is prepared by treating xanthene with sodium methylsulphinylmethide and dimethylsulphoxide, followed by 2-chloroethyl vinyl ether, treating the resulting 9,9-bis-(2<SP>1</SP>-vinyloxyethyl)xanthene with chromic acid in acetone and reacting the resulting xanthene-9-spiro-4<SP>1</SP>- tetrahydropyran-2<SP>1</SP>-one with methylamine. 9,9 - Di - (2<SP>1</SP>- methanesulphonyloxyethyl). xanthene is prepared by treating 9,9-bis-(2<SP>1</SP>- vinyloxyethyl)xanthene with aqueous HCl and reacting the resulting 9,9-bis-(2<SP>1</SP>-hydroxyethyl)- xanthene with methanesulphonyl chloride. The 4-methoxy and 2-chloro-5-methoxy derivatives are prepared in the same way. 1<SP>1</SP> - Cyclopropylcarbonyl - 4 - methoxyxanthene- 9 - spiro - 41 - piperidine is prepared by reacting 4-methoxyxanthene-9-spiro-41-piperidine with cyclopropane-carboxylic acid chloride. The corresponding 1<SP>1</SP>-cyclobutylcarbonyl compound is prepared analogously. 1<SP>1</SP> - Methyl - 4 - aminoxanthene - 9 - spiro - 4<SP>1</SP>- piperidine is prepared by reacting 1<SP>1</SP>-methylxanthene-9-spiro-4<SP>1</SP>-piperidine with hydroxylamine methyl ether and t-butyl lithium. 1<SP>1</SP> - Methylxanthene - 9 - spiro - 4<SP>1</SP>- piperidin- 2<SP>1</SP>,6<SP>1</SP>-dione is prepared by reacting xanthene with allyl bromide, treating the resulting 9,9- diallylxanthene with potassium permanganate, sodium metaperiodate and potassium carbonate in water, heating the resulting xanthene-9,9- diacetic acid with acetic anhydride and treating the resulting xanthene - 9 - spiro - 4<SP>1</SP>- tetrahydropyran-21,61-dione with methylamine. 1<SP>1</SP>,1<SP>1</SP> - Dimethyl - 4 - methoxyxanthene - 9- spiro - 4<SP>1</SP>- piperidinium chloride is prepared by treating 9,9 - bis - (2<SP>1</SP> - methane - sulphonyloxyethyl) - 4 - methoxyxanthene with ethanolic dimethylamine and passing the resulting 1,<SP>1</SP>1<SP>1</SP>- dimethyl - 4 - methoxyxanthene - 9 - spiro - 4<SP>1</SP>- piperidinium methanesulphonate dihydrate through an appropriate ion-exchange column. 4 - Hydroxy - 1 - methyl - 4 - (2<SP>1</SP>- phenoxy)- phenyl - piperidine is prepared by reacting 1- methyl-4-piperidone with diphenyl ether and n-butyl lithium in ether. 5 - Methoxy - 3 - methylthio - xanthone is prepared by reacting 3-chloro-5-methoxyxanthone with sodium thiomethoxide. 4 - Benzyloxy - 6 - methoxy - 11 - methylxanthene - 9 - spiro - 4<SP>1</SP>- piperidine is prepared by treating 3 - chloro - 5 - methoxyxanthone with boron tribromide, reacting the resulting 3 - chloro - 5 - hydroxyxanthone with benzyl bromide, treating the resulting 5-benzyloxy-3- chloroxanthone with methanol, reducing the resulting 5 - benzyloxy - 3 - methoxyxanthone and reacting the resulting 5-benzyloxy-3-methoxyxanthene with N - methyl - di - (2 - chloroethyl)amine. 1<SP>1</SP> - Phenoxycarbonylxanthene - 9 - spiro - 4<SP>1</SP>- piperidine is prepared by reacting 1<SP>1</SP>-methylxanthene - 9 - spiro - 41 - piperidine with phenyl chloroformate. R<SP>2</SP>,R<SP>3</SP>,R<SP>4</SP>,R<SP>5</SP> - Substituted xanthenes are prepared by reacting a R<SP>4</SP>,R<SP>5</SP>-substituted o-chlorobenzoic acid with a R<SP>2</SP>,R<SP>3</SP>-substituted phenol, heating the resulting o.(R<SP>2</SP>,R<SP>3</SP>-substituted phenoxy) - R<SP>4</SP>,R<SP>5</SP> - substituted benzoic acid with polyphosphoric acid and reducing the resulting R<SP>2</SP>,R<SP>3</SP>,R<SP>4</SP>,R<SP>5</SP>-substituted xanthone with a boranetetrahydrofuran complex. 2 - Fluwro - 5 - methoxyxanthone is prepared by reacting 2-methoxyphenol with potassium 2- chloro-5-nitrobenzoic acid, heating the resulting 2 - (2<SP>1</SP>- methoxyphenoxy) - 5 - nitrobenzoic acid with polyphosphoric acid, reducing the resulting 5 - methoxy - 2 - nitroxanthone with stannous chloride dihydrate-concentrated HCl, diazotizing the resulting 2-amino-5-methoxyxanthone hydrochloride and treating it with fluoroboric acid and heating the resulting diazonium tetrafluoroborate.