{"id":{"repo_id":"cent-lancashire","oai_identifier":"oai:clok.uclan.ac.uk:7872"},"canonical_url":"https://search.dev.ndltd.org/etd/cent-lancashire/oai:clok.uclan.ac.uk:7872","repository":{"repo_id":"cent-lancashire","name":"University of Central Lancashire","base_url":"https://clok.uclan.ac.uk/cgi/oai2"},"display":{"title":"Studies in Furobenzopyran Chemistry","abstract":"A series of 3-acyl(thio)chromones has been prepared. These compounds were acetalised with a variety of diols, with p-TsOH catalysis, under azeotropic conditions, to give the corresponding 3-acyl(thio)chromone acetals. A new rearrangement accompanies the formation of acetals from 3-acetyl- or 3-benzoyl- chromone giving a 2-methyl- or 2-phenyl- 3-formylchromone acetal. The rearrangement is initiated by conjugate addition of the diol to the chromone ring. The C-2 lithio derivatives of 3-acyl(thio)chromone acetals are generated by treatment with lithium diisopropylamide or lithium 2,2,6,6-tetramethylpiperidide (LTMP) in THF at low temperature. The anions have been intercepted with a variety of electrophiles. It was found that metallation with LTMP proceeds more efficiently. A number of novel 3-acyl-2-(1-hydroxyalkyl)(thio)chromone acetals has been prepared by electrophilic trapping with aldehydes. Three novel self-condensation dimers were obtained from lithiations of 3-acyl(thio)chromone acetals; the structures of two were established by X-ray crystallography. Mechanisms for their formation are presented. Whilst C-2 lithiation of 2-(4-oxo-4H[1]benzopyran-3-yl)-1,3-dioxane with n-BuLi does occur, the reaction is complex and leads, ultimately, to a benzofuranone derivative. The structure and relative stereochemistry of this compound, which possesses two 1,4-disposed stereogenic centres, was established by X-ray crystallography. The reaction also provides another compound, derived from 1,2-addition of n-BuLi to 2-(4-oxo-4H[1]benzopyran-3-yl)-1,3-dioxane. Lithiation of 2-(hydroxymethyl)chromone with LTMP initiates reduction ofthe pyranone ring, probably via a Single Electron Transfer mechanism. Electrophilic trapping of the intermediate anion with CICO2Et proceeds in a regio- and diastereospecific manner. Unmasking of the acetal function in 3-acyl-2- (1-hydroxyalkyl)(thio)chromone acetals is facile (p-TsOH in toluene) and proceeds with concomitant cyclisation to give novel 9H-furo[3,4-b][l]benzo(thio)pyran-9-ones. Cycloaddition reactions of the furobenzo(thio)pyranones have been investigated. When 3-methyl-9H-furo[3,4)[1]benzopyran-9-onereacts with methyl propiolate a pincer Diels-Alder reaction prevails, to give an octacyclic 2:1 adduct with complete regio- and stereo- specificity. The stereochemistry was established as syn exo-endo by X-ray crystallography. Dimethyl acetylenedicarboxylate reacts with 3-(4-methylphenyl)-9H-furo[3,4-b][1]benzopyran -9-one to give a mixture of the 1:1 and the anti exo-exo 2:1 adducts. 3H,9H-Furo[3,4b[1]benzopyran-1,9-dione has been obtained via a tandem acylation-SnAr reaction of ethyl 2-fluorobenzoylacetate. Protolysis of dimethyl 1,4-dihydro-1,4-epoxy4-(4-methylphenyl)-9-oxo-9H-thioxanthene-2,3-dicarboxylate gives the expected 1-hydroxythioxanthone derivative. However, the analogous 1,4-epoxyxanthene underwent an unprecedented hydrolytic cycloreversion to dimethyl 2-(4-methylphenyl) furan-3,4-dicarboxylate and 4-hydroxycoumarin. The acylation of 3-pyrrolidinodihydrothiophenes with 2-fluorobenzoyl chloride has been investigated as an entry to the 9H-thieno[3,4-b]benzopyran-9-one system. An unexpected product, 2,4-bis(2-fluorobenzoyl)-3-pyrrolidino-2,5-dihydrothiophene is formed predominantly.","abstract_html":"A series of 3-acyl(thio)chromones has been prepared. These compounds were acetalised with a variety of diols, with p-TsOH catalysis, under azeotropic conditions, to give the corresponding 3-acyl(thio)chromone acetals. A new rearrangement accompanies the formation of acetals from 3-acetyl- or 3-benzoyl- chromone giving a 2-methyl- or 2-phenyl- 3-formylchromone acetal. The rearrangement is initiated by conjugate addition of the diol to the chromone ring. The C-2 lithio derivatives of 3-acyl(thio)chromone acetals are generated by treatment with lithium diisopropylamide or lithium 2,2,6,6-tetramethylpiperidide (LTMP) in THF at low temperature. The anions have been intercepted with a variety of electrophiles. It was found that metallation with LTMP proceeds more efficiently. A number of novel 3-acyl-2-(1-hydroxyalkyl)(thio)chromone acetals has been prepared by electrophilic trapping with aldehydes. Three novel self-condensation dimers were obtained from lithiations of 3-acyl(thio)chromone acetals; the structures of two were established by X-ray crystallography. Mechanisms for their formation are presented. Whilst C-2 lithiation of 2-(4-oxo-4H[1]benzopyran-3-yl)-1,3-dioxane with n-BuLi does occur, the reaction is complex and leads, ultimately, to a benzofuranone derivative. The structure and relative stereochemistry of this compound, which possesses two 1,4-disposed stereogenic centres, was established by X-ray crystallography. The reaction also provides another compound, derived from 1,2-addition of n-BuLi to 2-(4-oxo-4H[1]benzopyran-3-yl)-1,3-dioxane. Lithiation of 2-(hydroxymethyl)chromone with LTMP initiates reduction ofthe pyranone ring, probably via a Single Electron Transfer mechanism. Electrophilic trapping of the intermediate anion with CICO2Et proceeds in a regio- and diastereospecific manner. Unmasking of the acetal function in 3-acyl-2- (1-hydroxyalkyl)(thio)chromone acetals is facile (p-TsOH in toluene) and proceeds with concomitant cyclisation to give novel 9H-furo[3,4-b][l]benzo(thio)pyran-9-ones. Cycloaddition reactions of the furobenzo(thio)pyranones have been investigated. When 3-methyl-9H-furo[3,4)[1]benzopyran-9-onereacts with methyl propiolate a pincer Diels-Alder reaction prevails, to give an octacyclic 2:1 adduct with complete regio- and stereo- specificity. The stereochemistry was established as syn exo-endo by X-ray crystallography. Dimethyl acetylenedicarboxylate reacts with 3-(4-methylphenyl)-9H-furo[3,4-b][1]benzopyran -9-one to give a mixture of the 1:1 and the anti exo-exo 2:1 adducts. 3H,9H-Furo[3,4b[1]benzopyran-1,9-dione has been obtained via a tandem acylation-SnAr reaction of ethyl 2-fluorobenzoylacetate. Protolysis of dimethyl 1,4-dihydro-1,4-epoxy4-(4-methylphenyl)-9-oxo-9H-thioxanthene-2,3-dicarboxylate gives the expected 1-hydroxythioxanthone derivative. However, the analogous 1,4-epoxyxanthene underwent an unprecedented hydrolytic cycloreversion to dimethyl 2-(4-methylphenyl) furan-3,4-dicarboxylate and 4-hydroxycoumarin. The acylation of 3-pyrrolidinodihydrothiophenes with 2-fluorobenzoyl chloride has been investigated as an entry to the 9H-thieno[3,4-b]benzopyran-9-one system. An unexpected product, 2,4-bis(2-fluorobenzoyl)-3-pyrrolidino-2,5-dihydrothiophene is formed predominantly.","abstract_has_math":false,"creators":["Daia, Gina Elena"],"institution":"University of Central Lancashire","degree_name":"phd","degree_level":"doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2000,"date_issued":"2000-06","date_published":"2000-06","updated_at":"2026-07-24T01:35:42Z","subjects":["F100 - Chemistry"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Daia, Gina Elena"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2000-06"]},{"key":"dc:date.issued","label":"Date","values":["2000-06"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Centre for Materials Science"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Central Lancashire"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://knowledge.lancashire.ac.uk/id/eprint/7872/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["phd"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["F100 - Chemistry"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://knowledge.lancashire.ac.uk/id/eprint/7872/1/Edmund%20Lane%20Oct00%20An%20investigation%20into%20the%20effects%20of%20inorganic%20element%20status%20on%20the%20accumulation%20and%20deposition%20of%20amyloid%20in%20vario%20Degree%20of%20Docto.pdf","https://knowledge.lancashire.ac.uk/id/eprint/7872/2/edmund%20lane.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["A series of 3-acyl(thio)chromones has been prepared. These compounds were acetalised with a variety of diols, with p-TsOH catalysis, under azeotropic conditions, to give the corresponding 3-acyl(thio)chromone acetals. A new rearrangement accompanies the formation of acetals from 3-acetyl- or 3-benzoyl- chromone giving a 2-methyl- or 2-phenyl- 3-formylchromone acetal. The rearrangement is initiated by conjugate addition of the diol to the chromone ring. The C-2 lithio derivatives of 3-acyl(thio)chromone acetals are generated by treatment with lithium diisopropylamide or lithium 2,2,6,6-tetramethylpiperidide (LTMP) in THF at low temperature. The anions have been intercepted with a variety of electrophiles. It was found that metallation with LTMP proceeds more efficiently. A number of novel 3-acyl-2-(1-hydroxyalkyl)(thio)chromone acetals has been prepared by electrophilic trapping with aldehydes. Three novel self-condensation dimers were obtained from lithiations of 3-acyl(thio)chromone acetals; the structures of two were established by X-ray crystallography. Mechanisms for their formation are presented. Whilst C-2 lithiation of 2-(4-oxo-4H[1]benzopyran-3-yl)-1,3-dioxane with n-BuLi does occur, the reaction is complex and leads, ultimately, to a benzofuranone derivative. The structure and relative stereochemistry of this compound, which possesses two 1,4-disposed stereogenic centres, was established by X-ray crystallography. The reaction also provides another compound, derived from 1,2-addition of n-BuLi to 2-(4-oxo-4H[1]benzopyran-3-yl)-1,3-dioxane. Lithiation of 2-(hydroxymethyl)chromone with LTMP initiates reduction ofthe pyranone ring, probably via a Single Electron Transfer mechanism. Electrophilic trapping of the intermediate anion with CICO2Et proceeds in a regio- and diastereospecific manner. Unmasking of the acetal function in 3-acyl-2- (1-hydroxyalkyl)(thio)chromone acetals is facile (p-TsOH in toluene) and proceeds with concomitant cyclisation to give novel 9H-furo[3,4-b][l]benzo(thio)pyran-9-ones. Cycloaddition reactions of the furobenzo(thio)pyranones have been investigated. When 3-methyl-9H-furo[3,4)[1]benzopyran-9-onereacts with methyl propiolate a pincer Diels-Alder reaction prevails, to give an octacyclic 2:1 adduct with complete regio- and stereo- specificity. The stereochemistry was established as syn exo-endo by X-ray crystallography. Dimethyl acetylenedicarboxylate reacts with 3-(4-methylphenyl)-9H-furo[3,4-b][1]benzopyran -9-one to give a mixture of the 1:1 and the anti exo-exo 2:1 adducts. 3H,9H-Furo[3,4b[1]benzopyran-1,9-dione has been obtained via a tandem acylation-SnAr reaction of ethyl 2-fluorobenzoylacetate. Protolysis of dimethyl 1,4-dihydro-1,4-epoxy4-(4-methylphenyl)-9-oxo-9H-thioxanthene-2,3-dicarboxylate gives the expected 1-hydroxythioxanthone derivative. However, the analogous 1,4-epoxyxanthene underwent an unprecedented hydrolytic cycloreversion to dimethyl 2-(4-methylphenyl) furan-3,4-dicarboxylate and 4-hydroxycoumarin. The acylation of 3-pyrrolidinodihydrothiophenes with 2-fluorobenzoyl chloride has been investigated as an entry to the 9H-thieno[3,4-b]benzopyran-9-one system. An unexpected product, 2,4-bis(2-fluorobenzoyl)-3-pyrrolidino-2,5-dihydrothiophene is formed predominantly."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Studies in Furobenzopyran Chemistry"]}]}],"canonical_facts":{"dc:creator":["Daia, Gina Elena"],"dc:date":["2000-06"],"dc:date.issued":["2000-06"],"dc:description.abstract":["A series of 3-acyl(thio)chromones has been prepared. These compounds were acetalised with a variety of diols, with p-TsOH catalysis, under azeotropic conditions, to give the corresponding 3-acyl(thio)chromone acetals. A new rearrangement accompanies the formation of acetals from 3-acetyl- or 3-benzoyl- chromone giving a 2-methyl- or 2-phenyl- 3-formylchromone acetal. The rearrangement is initiated by conjugate addition of the diol to the chromone ring. The C-2 lithio derivatives of 3-acyl(thio)chromone acetals are generated by treatment with lithium diisopropylamide or lithium 2,2,6,6-tetramethylpiperidide (LTMP) in THF at low temperature. The anions have been intercepted with a variety of electrophiles. It was found that metallation with LTMP proceeds more efficiently. A number of novel 3-acyl-2-(1-hydroxyalkyl)(thio)chromone acetals has been prepared by electrophilic trapping with aldehydes. Three novel self-condensation dimers were obtained from lithiations of 3-acyl(thio)chromone acetals; the structures of two were established by X-ray crystallography. Mechanisms for their formation are presented. Whilst C-2 lithiation of 2-(4-oxo-4H[1]benzopyran-3-yl)-1,3-dioxane with n-BuLi does occur, the reaction is complex and leads, ultimately, to a benzofuranone derivative. The structure and relative stereochemistry of this compound, which possesses two 1,4-disposed stereogenic centres, was established by X-ray crystallography. The reaction also provides another compound, derived from 1,2-addition of n-BuLi to 2-(4-oxo-4H[1]benzopyran-3-yl)-1,3-dioxane. Lithiation of 2-(hydroxymethyl)chromone with LTMP initiates reduction ofthe pyranone ring, probably via a Single Electron Transfer mechanism. Electrophilic trapping of the intermediate anion with CICO2Et proceeds in a regio- and diastereospecific manner. Unmasking of the acetal function in 3-acyl-2- (1-hydroxyalkyl)(thio)chromone acetals is facile (p-TsOH in toluene) and proceeds with concomitant cyclisation to give novel 9H-furo[3,4-b][l]benzo(thio)pyran-9-ones. Cycloaddition reactions of the furobenzo(thio)pyranones have been investigated. When 3-methyl-9H-furo[3,4)[1]benzopyran-9-onereacts with methyl propiolate a pincer Diels-Alder reaction prevails, to give an octacyclic 2:1 adduct with complete regio- and stereo- specificity. The stereochemistry was established as syn exo-endo by X-ray crystallography. Dimethyl acetylenedicarboxylate reacts with 3-(4-methylphenyl)-9H-furo[3,4-b][1]benzopyran -9-one to give a mixture of the 1:1 and the anti exo-exo 2:1 adducts. 3H,9H-Furo[3,4b[1]benzopyran-1,9-dione has been obtained via a tandem acylation-SnAr reaction of ethyl 2-fluorobenzoylacetate. Protolysis of dimethyl 1,4-dihydro-1,4-epoxy4-(4-methylphenyl)-9-oxo-9H-thioxanthene-2,3-dicarboxylate gives the expected 1-hydroxythioxanthone derivative. However, the analogous 1,4-epoxyxanthene underwent an unprecedented hydrolytic cycloreversion to dimethyl 2-(4-methylphenyl) furan-3,4-dicarboxylate and 4-hydroxycoumarin. The acylation of 3-pyrrolidinodihydrothiophenes with 2-fluorobenzoyl chloride has been investigated as an entry to the 9H-thieno[3,4-b]benzopyran-9-one system. An unexpected product, 2,4-bis(2-fluorobenzoyl)-3-pyrrolidino-2,5-dihydrothiophene is formed predominantly."],"dc:format":["application/pdf"],"dc:identifier.uri":["https://knowledge.lancashire.ac.uk/id/eprint/7872/1/Edmund%20Lane%20Oct00%20An%20investigation%20into%20the%20effects%20of%20inorganic%20element%20status%20on%20the%20accumulation%20and%20deposition%20of%20amyloid%20in%20vario%20Degree%20of%20Docto.pdf","https://knowledge.lancashire.ac.uk/id/eprint/7872/2/edmund%20lane.pdf"],"dc:language":["en"],"dc:publisher.department":["Centre for Materials Science"],"dc:publisher.institution":["University of Central Lancashire"],"dc:relation.isreferencedby":["https://knowledge.lancashire.ac.uk/id/eprint/7872/"],"dc:subject":["F100 - Chemistry"],"dc:title":["Studies in Furobenzopyran Chemistry"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["doctoral"],"dc:type.qualificationname":["phd"]},"updated_at":"2026-07-24T01:35:42Z"}