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A general and stereoselective approach to 14-membered cyclic bis-semicarbazones involving BF3-catalyzed amidoalkylation of 2-(trimethylsilyloxy)propene
A general and stereoselective five-step approach to 14-membered cyclic bis-semicarbazones, 5,12-diaryl-7,14-dimethyl-1,2,4,8,9,11-hexaazacyclotetradeca-7,14-diene-3,10-diones, starting from aldehyde semicarbazones has been developed. The key intermediates, 4-(3-oxobut-1-yl)semicarbazones, were prepa...
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Published in: | Organic & biomolecular chemistry 2022-06, Vol.20 (22), p.4569-4588 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Online Access: | Get full text |
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Summary: | A general and stereoselective five-step approach to 14-membered cyclic bis-semicarbazones, 5,12-diaryl-7,14-dimethyl-1,2,4,8,9,11-hexaazacyclotetradeca-7,14-diene-3,10-diones, starting from aldehyde semicarbazones has been developed. The key intermediates, 4-(3-oxobut-1-yl)semicarbazones, were prepared by BF3-catalyzed amidoalkylation of 2-(trimethylsilyloxy)propene with 4-[(aryl)(methoxy)methyl]- or 4-[(aryl)(tosyl)methyl]semicarbazones. Treatment of these intermediates with excess of hydrazine gave hydrazones of 4-(3-oxobut-1-yl)semicarbazones or 4-(3-oxobut-1-yl)semicarbazides, which in the presence of TsOH were converted into the target macrocycles. All steps of this approach could be scaled up easily to the multi-gram level. |
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ISSN: | 1477-0520 1477-0539 |
DOI: | 10.1039/d2ob00644h |