{"id":{"repo_id":"cent-lancashire","oai_identifier":"oai:clok.uclan.ac.uk:20915"},"canonical_url":"https://search.dev.ndltd.org/etd/cent-lancashire/oai:clok.uclan.ac.uk:20915","repository":{"repo_id":"cent-lancashire","name":"University of Central Lancashire","base_url":"https://clok.uclan.ac.uk/cgi/oai2"},"display":{"title":"Studies in Benzopyran chemistry","abstract":"6-Bromo-, 7-bromo-, 8-bromo- and 6,8-dibromo- 2,2-dimethylchromenes have been synthesised. The 6-bromoand 8-bromo-derivatives were prepared by Claisen rearrangement of aryl propargyl ethers, derived from phenols and 3-chloro-3-methylbut-1-yne. 7-Bromo- and 6,8-dibromo-2,2-dimethylchromenes were obtained by dehydration of the corresponding chroman-4-ols, available from the chroman-4-ones. Addition of bromine to the chromenes gave the corresponding 3,4-dibromochromans which were hydrolysed with aqueous acetone to yield the 3-bromochroman-4-ols. These chromanols were also obtained directly from the chromenes by reaction with N-bromosuccinimide in moist dimethyl sulphoxide. The bromohydrins were oxidised to 3-bromochroman-4-ones and conversion to the chroman-4-ones was achieved by subsequent reaction with benzo±n. The same chroman-4-ones have been synthesised by the condensation of the appropriate brominated 2-hydroxyacetophenories with acetone in the presence of pyrrolidine. Róduction of the chroman-4-ones using sodium borohydride afforded the chroman-4-ols. The bromohydrins have been converted to the corresponding 3,4-epoxychromans and ring opening reactions with lithium aluminium hydride, hydrobromic acid and methanol were studied. Dehydration of the 3-bromochroman- 4-ols yielded the 3-bromochromenes. The isomeric 4-bromochromenes resulted from treatment of the -- - 3,4-dibromochromans with sodium methoxide. Routes to 2,2-dimethylchroman-4-ones based on the Fries rearrangement of phenyl 3-methylbut-2-enoates and the reaction between a phenol and 3-methylbut-2-enoic acid have been examined. In many instances, the isomeric 3,4-dihydro-4,4-dimethylcoumarins were formed either as sole products or admixed with chromanones. Treatment of 4-bromo- 1 6-bromo-, 7-bromo- and 8-bromo-2 ,2-dimethylchromenes with n-butyl-lithium followed by Michler's ketone has given a series of dyes related to Malachite Green, h'.it incorporating an oxygen heterocyclic function. The 6- and 7-bromochromenes gave longitudinally conjugated dyes, whereas transversely conjugated dyes resulted from the 4- and 8-bromochromenes.","abstract_html":"6-Bromo-, 7-bromo-, 8-bromo- and 6,8-dibromo- 2,2-dimethylchromenes have been synthesised. The 6-bromoand 8-bromo-derivatives were prepared by Claisen rearrangement of aryl propargyl ethers, derived from phenols and 3-chloro-3-methylbut-1-yne. 7-Bromo- and 6,8-dibromo-2,2-dimethylchromenes were obtained by dehydration of the corresponding chroman-4-ols, available from the chroman-4-ones. Addition of bromine to the chromenes gave the corresponding 3,4-dibromochromans which were hydrolysed with aqueous acetone to yield the 3-bromochroman-4-ols. These chromanols were also obtained directly from the chromenes by reaction with N-bromosuccinimide in moist dimethyl sulphoxide. The bromohydrins were oxidised to 3-bromochroman-4-ones and conversion to the chroman-4-ones was achieved by subsequent reaction with benzo±n. The same chroman-4-ones have been synthesised by the condensation of the appropriate brominated 2-hydroxyacetophenories with acetone in the presence of pyrrolidine. Róduction of the chroman-4-ones using sodium borohydride afforded the chroman-4-ols. The bromohydrins have been converted to the corresponding 3,4-epoxychromans and ring opening reactions with lithium aluminium hydride, hydrobromic acid and methanol were studied. Dehydration of the 3-bromochroman- 4-ols yielded the 3-bromochromenes. The isomeric 4-bromochromenes resulted from treatment of the -- - 3,4-dibromochromans with sodium methoxide. Routes to 2,2-dimethylchroman-4-ones based on the Fries rearrangement of phenyl 3-methylbut-2-enoates and the reaction between a phenol and 3-methylbut-2-enoic acid have been examined. In many instances, the isomeric 3,4-dihydro-4,4-dimethylcoumarins were formed either as sole products or admixed with chromanones. Treatment of 4-bromo- 1 6-bromo-, 7-bromo- and 8-bromo-2 ,2-dimethylchromenes with n-butyl-lithium followed by Michler's ketone has given a series of dyes related to Malachite Green, h'.it incorporating an oxygen heterocyclic function. The 6- and 7-bromochromenes gave longitudinally conjugated dyes, whereas transversely conjugated dyes resulted from the 4- and 8-bromochromenes.","abstract_has_math":false,"creators":["Clayton, Stephen Edward"],"institution":"Lancashire Polytechnic","degree_name":"phd","degree_level":"doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1985,"date_issued":"1985-10","date_published":"1985-10","updated_at":"2026-07-24T01:36:20Z","subjects":["F112 - Colour 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":["Clayton, Stephen Edward"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["1985-10-01"]},{"key":"dc:date.issued","label":"Date","values":["1985-10"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Colour Chemistry"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["Lancashire Polytechnic"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://knowledge.lancashire.ac.uk/id/eprint/20915/"]},{"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":["F112 - Colour 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/20915/1/20915%20Stephen%20Edward%20Clayton%20Oct85%20studies%20in%20benzopyran%20chemistry%20degree%20of%20Doctor%20of%20Philosophy%20unpublished%20Oct85%20University%20of%20Central%20Lancashire%20chemistry%20248.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["6-Bromo-, 7-bromo-, 8-bromo- and 6,8-dibromo- 2,2-dimethylchromenes have been synthesised. The 6-bromoand 8-bromo-derivatives were prepared by Claisen rearrangement of aryl propargyl ethers, derived from phenols and 3-chloro-3-methylbut-1-yne. 7-Bromo- and 6,8-dibromo-2,2-dimethylchromenes were obtained by dehydration of the corresponding chroman-4-ols, available from the chroman-4-ones. Addition of bromine to the chromenes gave the corresponding 3,4-dibromochromans which were hydrolysed with aqueous acetone to yield the 3-bromochroman-4-ols. These chromanols were also obtained directly from the chromenes by reaction with N-bromosuccinimide in moist dimethyl sulphoxide. The bromohydrins were oxidised to 3-bromochroman-4-ones and conversion to the chroman-4-ones was achieved by subsequent reaction with benzo±n. The same chroman-4-ones have been synthesised by the condensation of the appropriate brominated 2-hydroxyacetophenories with acetone in the presence of pyrrolidine. Róduction of the chroman-4-ones using sodium borohydride afforded the chroman-4-ols. The bromohydrins have been converted to the corresponding 3,4-epoxychromans and ring opening reactions with lithium aluminium hydride, hydrobromic acid and methanol were studied. Dehydration of the 3-bromochroman- 4-ols yielded the 3-bromochromenes. The isomeric 4-bromochromenes resulted from treatment of the -- - 3,4-dibromochromans with sodium methoxide. Routes to 2,2-dimethylchroman-4-ones based on the Fries rearrangement of phenyl 3-methylbut-2-enoates and the reaction between a phenol and 3-methylbut-2-enoic acid have been examined. In many instances, the isomeric 3,4-dihydro-4,4-dimethylcoumarins were formed either as sole products or admixed with chromanones. Treatment of 4-bromo- 1 6-bromo-, 7-bromo- and 8-bromo-2 ,2-dimethylchromenes with n-butyl-lithium followed by Michler's ketone has given a series of dyes related to Malachite Green, h'.it incorporating an oxygen heterocyclic function. The 6- and 7-bromochromenes gave longitudinally conjugated dyes, whereas transversely conjugated dyes resulted from the 4- and 8-bromochromenes."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Studies in Benzopyran chemistry"]}]}],"canonical_facts":{"dc:creator":["Clayton, Stephen Edward"],"dc:date":["1985-10-01"],"dc:date.issued":["1985-10"],"dc:description.abstract":["6-Bromo-, 7-bromo-, 8-bromo- and 6,8-dibromo- 2,2-dimethylchromenes have been synthesised. The 6-bromoand 8-bromo-derivatives were prepared by Claisen rearrangement of aryl propargyl ethers, derived from phenols and 3-chloro-3-methylbut-1-yne. 7-Bromo- and 6,8-dibromo-2,2-dimethylchromenes were obtained by dehydration of the corresponding chroman-4-ols, available from the chroman-4-ones. Addition of bromine to the chromenes gave the corresponding 3,4-dibromochromans which were hydrolysed with aqueous acetone to yield the 3-bromochroman-4-ols. These chromanols were also obtained directly from the chromenes by reaction with N-bromosuccinimide in moist dimethyl sulphoxide. The bromohydrins were oxidised to 3-bromochroman-4-ones and conversion to the chroman-4-ones was achieved by subsequent reaction with benzo±n. The same chroman-4-ones have been synthesised by the condensation of the appropriate brominated 2-hydroxyacetophenories with acetone in the presence of pyrrolidine. Róduction of the chroman-4-ones using sodium borohydride afforded the chroman-4-ols. The bromohydrins have been converted to the corresponding 3,4-epoxychromans and ring opening reactions with lithium aluminium hydride, hydrobromic acid and methanol were studied. Dehydration of the 3-bromochroman- 4-ols yielded the 3-bromochromenes. The isomeric 4-bromochromenes resulted from treatment of the -- - 3,4-dibromochromans with sodium methoxide. Routes to 2,2-dimethylchroman-4-ones based on the Fries rearrangement of phenyl 3-methylbut-2-enoates and the reaction between a phenol and 3-methylbut-2-enoic acid have been examined. In many instances, the isomeric 3,4-dihydro-4,4-dimethylcoumarins were formed either as sole products or admixed with chromanones. Treatment of 4-bromo- 1 6-bromo-, 7-bromo- and 8-bromo-2 ,2-dimethylchromenes with n-butyl-lithium followed by Michler's ketone has given a series of dyes related to Malachite Green, h'.it incorporating an oxygen heterocyclic function. The 6- and 7-bromochromenes gave longitudinally conjugated dyes, whereas transversely conjugated dyes resulted from the 4- and 8-bromochromenes."],"dc:format":["application/pdf"],"dc:identifier.uri":["https://knowledge.lancashire.ac.uk/id/eprint/20915/1/20915%20Stephen%20Edward%20Clayton%20Oct85%20studies%20in%20benzopyran%20chemistry%20degree%20of%20Doctor%20of%20Philosophy%20unpublished%20Oct85%20University%20of%20Central%20Lancashire%20chemistry%20248.pdf"],"dc:language":["en"],"dc:publisher.department":["Colour Chemistry"],"dc:publisher.institution":["Lancashire Polytechnic"],"dc:relation.isreferencedby":["https://knowledge.lancashire.ac.uk/id/eprint/20915/"],"dc:subject":["F112 - Colour chemistry"],"dc:title":["Studies in Benzopyran chemistry"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["doctoral"],"dc:type.qualificationname":["phd"]},"updated_at":"2026-07-24T01:36:20Z"}