{"id":{"repo_id":"greenwich","oai_identifier":"oai:gala.gre.ac.uk:8673"},"canonical_url":"https://search.dev.ndltd.org/etd/greenwich/oai:gala.gre.ac.uk:8673","repository":{"repo_id":"greenwich","name":"University of Greenwich","base_url":"https://gala.gre.ac.uk/cgi/oai2"},"display":{"title":"Studies in isothiazole chemistry: I. isothiazolo [5,4-b] pyridines. II. approaches to isothiazolynes","abstract":"The first part of this thesis describes investigations on the synthesis and chemistry of isothiazolo[5,4-b] pyridines. The syntheses of a number of alkyl isothiazolo[5,4-b] pyridines from 5-amino-3-methylisothiazole under conditions of the Skraup reaction are described and their nuclear magnetic resonance spectra are discussed. The reactions of 3-methyl- and 3,6-dimethylisothiazolo[5,4-b] pyridine have been studied. In particular they did not undergo nitration under the conditions employed and whereas the 3-methyl compound did not condense with benzaldehyde, 3,6-dimethylisothiazolo[5,4-b] pyridine gave mono-styryl products with benzaldehyde, and p-nitrobenzaldehyde. Potassium permanganate oxidation gave isothiazolo[5,4-b] pyrid-3(2H)-one 1,1-dioxides rather than the expected isothiazolo[5,4-b] pyridine carboxylic acids and chromic acid oxidation resulted in cleavage of the isothiazole ring to give 2,3-disubstituted pyridines. Ethyl 4-hydroxy-3-methylisothiazolo[5,4-b] pyridine-5-earboxylabe was readily obtained by thermal cyclisation of the malonate from 5-amino-3-methylisothiazole and ethoxymethylenemalonic ester. The hydroxyl ester was converted to a number of substituted isothiazolo[5,4-b] pyridines. In addition it has been established that methylation at nitrogen rather than oxygen occurs with both the 4-hydroxy ester and the 4-hydroxy compound which has been shown to exist preferentially in the carbonyl form, namely 3-methylisothiazolo[5,4-b] _7pyrid-4-one. The reaction of 5-amino-3-methylisothiazole with ethylacetoacetate and with acetylacetone under the conditions of the Conrad Limpach reaction and the Combes reaction respectively, did not give isothiazolo[5,4-b] pyridines. The latter gave a product which has been tentatively formulated as 5-acetyl-3,4-dimethylisothiazole. The second part of this work describes the synthesis of 5-amino-3-chloroisothiazole-4-carboxylic acid, 4-amino-3-methylisothiazole- 5-carboxylic acid and 4-aminoisothiazole-3-carboxylic acid and experiments aimed at investigating the possible intermediacy of isothiazolynes. Attempts to generate and trap isothiazolynes by their aprotic diazotisation with isoainyl nitrite in the presence of 2,3,4,5-tetraphenylcyclopentadienone gave only small quantities of isothiazoles in addition to a variety of oxidation products derived from the arynophile. 4-Amino3-methylisothiazole-5-carboxylic acid gave isothiazolyl-substituted products when furan and anthracene were used as trapping agents, and it was found that the reaction of isothiazole-4-diazonium carboxylate hydrochloride and propylene oxide in the presence of furan gave 4,-cyano-1,2,3-thiadiazole. In none of the reactions investigated was there any evidence for the formation of inothiazolyne intermediates.","abstract_html":"The first part of this thesis describes investigations on the synthesis and chemistry of isothiazolo[5,4-b] pyridines. The syntheses of a number of alkyl isothiazolo[5,4-b] pyridines from 5-amino-3-methylisothiazole under conditions of the Skraup reaction are described and their nuclear magnetic resonance spectra are discussed. The reactions of 3-methyl- and 3,6-dimethylisothiazolo[5,4-b] pyridine have been studied. In particular they did not undergo nitration under the conditions employed and whereas the 3-methyl compound did not condense with benzaldehyde, 3,6-dimethylisothiazolo[5,4-b] pyridine gave mono-styryl products with benzaldehyde, and p-nitrobenzaldehyde. Potassium permanganate oxidation gave isothiazolo[5,4-b] pyrid-3(2H)-one 1,1-dioxides rather than the expected isothiazolo[5,4-b] pyridine carboxylic acids and chromic acid oxidation resulted in cleavage of the isothiazole ring to give 2,3-disubstituted pyridines. Ethyl 4-hydroxy-3-methylisothiazolo[5,4-b] pyridine-5-earboxylabe was readily obtained by thermal cyclisation of the malonate from 5-amino-3-methylisothiazole and ethoxymethylenemalonic ester. The hydroxyl ester was converted to a number of substituted isothiazolo[5,4-b] pyridines. In addition it has been established that methylation at nitrogen rather than oxygen occurs with both the 4-hydroxy ester and the 4-hydroxy compound which has been shown to exist preferentially in the carbonyl form, namely 3-methylisothiazolo[5,4-b] _7pyrid-4-one. The reaction of 5-amino-3-methylisothiazole with ethylacetoacetate and with acetylacetone under the conditions of the Conrad Limpach reaction and the Combes reaction respectively, did not give isothiazolo[5,4-b] pyridines. The latter gave a product which has been tentatively formulated as 5-acetyl-3,4-dimethylisothiazole. The second part of this work describes the synthesis of 5-amino-3-chloroisothiazole-4-carboxylic acid, 4-amino-3-methylisothiazole- 5-carboxylic acid and 4-aminoisothiazole-3-carboxylic acid and experiments aimed at investigating the possible intermediacy of isothiazolynes. Attempts to generate and trap isothiazolynes by their aprotic diazotisation with isoainyl nitrite in the presence of 2,3,4,5-tetraphenylcyclopentadienone gave only small quantities of isothiazoles in addition to a variety of oxidation products derived from the arynophile. 4-Amino3-methylisothiazole-5-carboxylic acid gave isothiazolyl-substituted products when furan and anthracene were used as trapping agents, and it was found that the reaction of isothiazole-4-diazonium carboxylate hydrochloride and propylene oxide in the presence of furan gave 4,-cyano-1,2,3-thiadiazole. In none of the reactions investigated was there any evidence for the formation of inothiazolyne intermediates.","abstract_has_math":false,"creators":["Hunma, Rannoo Rajahram"],"institution":"Thames Polytechnic","degree_name":"phd","degree_level":"doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Rogers, V."],"committee_chairs":[],"committee_members":[],"year":1973,"date_issued":"1973-10","date_published":"1973-10","updated_at":"2026-07-24T02:25:45Z","subjects":["QD 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:contributor.advisor","label":"Advisor","values":["Rogers, V."]},{"key":"dc:creator","label":"Author","values":["Hunma, Rannoo Rajahram"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["1973-10"]},{"key":"dc:date.issued","label":"Date","values":["1973-10"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["School of Chemistry"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["Thames Polytechnic"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://gala.gre.ac.uk/id/eprint/8673/"]},{"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":["QD 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://gala.gre.ac.uk/id/eprint/8673/1/Rannoo_Rajahram_Hunma_1973.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The first part of this thesis describes investigations on the synthesis and chemistry of isothiazolo[5,4-b] pyridines. The syntheses of a number of alkyl isothiazolo[5,4-b] pyridines from 5-amino-3-methylisothiazole under conditions of the Skraup reaction are described and their nuclear magnetic resonance spectra are discussed. The reactions of 3-methyl- and 3,6-dimethylisothiazolo[5,4-b] pyridine have been studied. In particular they did not undergo nitration under the conditions employed and whereas the 3-methyl compound did not condense with benzaldehyde, 3,6-dimethylisothiazolo[5,4-b] pyridine gave mono-styryl products with benzaldehyde, and p-nitrobenzaldehyde. Potassium permanganate oxidation gave isothiazolo[5,4-b] pyrid-3(2H)-one 1,1-dioxides rather than the expected isothiazolo[5,4-b] pyridine carboxylic acids and chromic acid oxidation resulted in cleavage of the isothiazole ring to give 2,3-disubstituted pyridines. Ethyl 4-hydroxy-3-methylisothiazolo[5,4-b] pyridine-5-earboxylabe was readily obtained by thermal cyclisation of the malonate from 5-amino-3-methylisothiazole and ethoxymethylenemalonic ester. The hydroxyl ester was converted to a number of substituted isothiazolo[5,4-b] pyridines. In addition it has been established that methylation at nitrogen rather than oxygen occurs with both the 4-hydroxy ester and the 4-hydroxy compound which has been shown to exist preferentially in the carbonyl form, namely 3-methylisothiazolo[5,4-b] _7pyrid-4-one. The reaction of 5-amino-3-methylisothiazole with ethylacetoacetate and with acetylacetone under the conditions of the Conrad Limpach reaction and the Combes reaction respectively, did not give isothiazolo[5,4-b] pyridines. The latter gave a product which has been tentatively formulated as 5-acetyl-3,4-dimethylisothiazole. The second part of this work describes the synthesis of 5-amino-3-chloroisothiazole-4-carboxylic acid, 4-amino-3-methylisothiazole- 5-carboxylic acid and 4-aminoisothiazole-3-carboxylic acid and experiments aimed at investigating the possible intermediacy of isothiazolynes. Attempts to generate and trap isothiazolynes by their aprotic diazotisation with isoainyl nitrite in the presence of 2,3,4,5-tetraphenylcyclopentadienone gave only small quantities of isothiazoles in addition to a variety of oxidation products derived from the arynophile. 4-Amino3-methylisothiazole-5-carboxylic acid gave isothiazolyl-substituted products when furan and anthracene were used as trapping agents, and it was found that the reaction of isothiazole-4-diazonium carboxylate hydrochloride and propylene oxide in the presence of furan gave 4,-cyano-1,2,3-thiadiazole. In none of the reactions investigated was there any evidence for the formation of inothiazolyne intermediates."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Studies in isothiazole chemistry: I. isothiazolo [5,4-b] pyridines. II. approaches to isothiazolynes"]}]}],"canonical_facts":{"dc:contributor.advisor":["Rogers, V."],"dc:creator":["Hunma, Rannoo Rajahram"],"dc:date":["1973-10"],"dc:date.issued":["1973-10"],"dc:description.abstract":["The first part of this thesis describes investigations on the synthesis and chemistry of isothiazolo[5,4-b] pyridines. The syntheses of a number of alkyl isothiazolo[5,4-b] pyridines from 5-amino-3-methylisothiazole under conditions of the Skraup reaction are described and their nuclear magnetic resonance spectra are discussed. The reactions of 3-methyl- and 3,6-dimethylisothiazolo[5,4-b] pyridine have been studied. In particular they did not undergo nitration under the conditions employed and whereas the 3-methyl compound did not condense with benzaldehyde, 3,6-dimethylisothiazolo[5,4-b] pyridine gave mono-styryl products with benzaldehyde, and p-nitrobenzaldehyde. Potassium permanganate oxidation gave isothiazolo[5,4-b] pyrid-3(2H)-one 1,1-dioxides rather than the expected isothiazolo[5,4-b] pyridine carboxylic acids and chromic acid oxidation resulted in cleavage of the isothiazole ring to give 2,3-disubstituted pyridines. Ethyl 4-hydroxy-3-methylisothiazolo[5,4-b] pyridine-5-earboxylabe was readily obtained by thermal cyclisation of the malonate from 5-amino-3-methylisothiazole and ethoxymethylenemalonic ester. The hydroxyl ester was converted to a number of substituted isothiazolo[5,4-b] pyridines. In addition it has been established that methylation at nitrogen rather than oxygen occurs with both the 4-hydroxy ester and the 4-hydroxy compound which has been shown to exist preferentially in the carbonyl form, namely 3-methylisothiazolo[5,4-b] _7pyrid-4-one. The reaction of 5-amino-3-methylisothiazole with ethylacetoacetate and with acetylacetone under the conditions of the Conrad Limpach reaction and the Combes reaction respectively, did not give isothiazolo[5,4-b] pyridines. The latter gave a product which has been tentatively formulated as 5-acetyl-3,4-dimethylisothiazole. The second part of this work describes the synthesis of 5-amino-3-chloroisothiazole-4-carboxylic acid, 4-amino-3-methylisothiazole- 5-carboxylic acid and 4-aminoisothiazole-3-carboxylic acid and experiments aimed at investigating the possible intermediacy of isothiazolynes. Attempts to generate and trap isothiazolynes by their aprotic diazotisation with isoainyl nitrite in the presence of 2,3,4,5-tetraphenylcyclopentadienone gave only small quantities of isothiazoles in addition to a variety of oxidation products derived from the arynophile. 4-Amino3-methylisothiazole-5-carboxylic acid gave isothiazolyl-substituted products when furan and anthracene were used as trapping agents, and it was found that the reaction of isothiazole-4-diazonium carboxylate hydrochloride and propylene oxide in the presence of furan gave 4,-cyano-1,2,3-thiadiazole. In none of the reactions investigated was there any evidence for the formation of inothiazolyne intermediates."],"dc:format":["application/pdf"],"dc:identifier.uri":["https://gala.gre.ac.uk/id/eprint/8673/1/Rannoo_Rajahram_Hunma_1973.pdf"],"dc:language":["en"],"dc:publisher.department":["School of Chemistry"],"dc:publisher.institution":["Thames Polytechnic"],"dc:relation.isreferencedby":["https://gala.gre.ac.uk/id/eprint/8673/"],"dc:subject":["QD Chemistry"],"dc:title":["Studies in isothiazole chemistry: I. isothiazolo [5,4-b] pyridines. II. approaches to isothiazolynes"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["doctoral"],"dc:type.qualificationname":["phd"]},"updated_at":"2026-07-24T02:25:45Z"}