Synthetic Studies in the Alkaloid Field

Crowder, John R (1956) Synthetic Studies in the Alkaloid Field. PhD thesis, University of Glasgow.

Abstract

The aim of the work has been to devise a method for synthesising 3-(4-carboxymethyl-phenoxy)-4:5-dimethoxy-phenylethylamine on a sufficiently large scale for use in a projected synthesis of cycleanine and of 00'-dimethyltubocurarine chloride. Part I ACTIVE CHLORO-COMPOUNDS AS INTERMEDIATES The principal difficulty in the work centres round the formation of the diphenyl ether link. Guaiacol, as a model, condensed with methyl 4-chloro-3:5-dinitro benzoate to give methyl-3:5-dinitro-4-(2-methoxy-phenoxy)-benzoate. The nitro-groups were replaced by iodo-groups, which were satisfactorily removed by reduction. 2:3-dimethoxy-5-(2-phthalimido-ethyl)phenol was prepared and gave methyl 3:5-dinitro-4-[2:3-dimethoxy-5-(2-phthalimidoethyl)-phenoxy]-benzoate. Replacement of the nitro-groups with iodine gave by-products together with the di-iodo compound. Further treatment of this gave a small amount of 3-(4-carboxy-phenoxy)-4:5-dimethoxyphenyl-ethylamine. Methyl 4-chloro-3-nitro-benzoate condensed with guaiacol and isovanillin as models, to give the corresponding diphenyl ethers. The nitro-groups were satisfactorily removed by conversion to the diazo compounds and treatment with hypophosphorous acid. The same nitro-ester condensed with 3:4-dimethyl-gallaldehyde, to give methyl 5-nitro-4-(2:3-dimethoxy-5-formyl-pheno2y)-benzoate, the nitro-group was removed from this, and treatment of the product gave 5-(4-carboxy-phenoxy)-4:5-dimethoxy-phenyl-ethylamine. This last stage merits further investigation. Part II DIPHENYLIODONIUM COMPOUNDS AS INTERMEDIATES 4:4' -Dimethoxycarbonylmethyl-diphenyliodonium salts were prepared and, on treatment with guaiacol gave methyl-4-(2-methoxy-phenoxy)-phenylacetate. Methyl 4-[2-methoxy-5-(2-phthalimidoethyl)-phenoxy]-phenylacetate was prepared similarly from the corresponding phenol, but no product could be obtained after treatment of the iodonium salt with 2:3-dimethoxy-5-(2-phthalimidoethyl)-phenol.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Organic chemistry
• Date of Award: 1956
• Depositing User: Enlighten Team
• Unique ID: glathesis:1956-79213
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 05 Mar 2020 11:27
• Last Modified: 05 Mar 2020 11:27
• URI: https://theses.gla.ac.uk/id/eprint/79213