| Title: |
A new and efficient access to thiazoline-4-carboxylates and cysteine derivatives incorporating cyclopropyl groups |
| Authors: |
Notzel, M. W.; Labahn, T.; Es-Sayed, M.; Meijere, Armin de |
| Contributors: |
Notzel, M. W.; Labahn, T.; Es-Sayed, M.; Meijere, Armin de |
| Publication Year: |
2001 |
| Collection: |
Georg-August-Universität Göttingen: GoeScholar |
| Description: |
Under basic conditions (NaHCO3, MeCN), thiocarboxamides 2, including NN-thioureas, cleanly undergo Michael addition onto 2-chloro-2-cyclopropylideneacetates 1, attacking through the sulfur, and this is followed by an intramolecular substitution to afford 5-spirocyclopropane-annelated thiazoline-4-carboxylates 4 in 37-92% yields. The thiazolines 4 are cysteine derivatives that possess a cyclopropyl or substituted cyclopropyl group in place of the gem-dimethyl-substituted beta -carbon atom of penicillamine; they can be hydrolyzed to the hydrochloride salt of the amino acid 5 by heating in acid. Under acidic conditions (CH2Cl2, HCl), the Michael adducts 7 of thioamides 2 onto 1 are formed in high to virtually quantitative yields. When treated with NaHCO3 in MeCN, the adducts 7 cyclize to thiazolinecarboxylates 4 (51-82%), but in the presence of Ti(OiPr)(4) they form spirocyclopropane-annelated thiazinones 8 (19-88%). |
| Document Type: |
article in journal/newspaper |
| Language: |
unknown |
| ISBN: |
978-0-00-170584-5; 0-00-170584-9 |
| Relation: |
000170584900003 |
| Availability: |
https://resolver.sub.uni-goettingen.de/purl?gro-2/21029 |
| Rights: |
info:eu-repo/semantics/openAccess |
| Accession Number: |
edsbas.B71D1B73 |
| Database: |
BASE |