Crystal structures of three cyclohexane-based γ-spirolactams: determination of configurations and conformations
Abstract The title compounds, 2-azaspiro[4.5]deca-1-one, C9H15NO, (1a), cis-8-methyl-2-azaspiro[4.5]deca-1-one, C10H17NO, (1b), and trans-8-methyl-2-azaspiro[4.5]deca-1-one, C10H17NO, (1c), were synthesized from benzoic acids 2 in only 3 steps in high yields. Crystallization from n-hexane afforded s...
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doaj-571c1069f3344ab4bfa6d7488eb0d67e2020-11-25T03:49:19ZengBMCBMC Chemistry2661-801X2019-05-011311910.1186/s13065-019-0586-7Crystal structures of three cyclohexane-based γ-spirolactams: determination of configurations and conformationsTobias Krueger0Alexandra Kelling1Torsten Linker2Uwe Schilde3Institute of Chemistry, University of PotsdamInstitute of Chemistry, University of PotsdamInstitute of Chemistry, University of PotsdamInstitute of Chemistry, University of PotsdamAbstract The title compounds, 2-azaspiro[4.5]deca-1-one, C9H15NO, (1a), cis-8-methyl-2-azaspiro[4.5]deca-1-one, C10H17NO, (1b), and trans-8-methyl-2-azaspiro[4.5]deca-1-one, C10H17NO, (1c), were synthesized from benzoic acids 2 in only 3 steps in high yields. Crystallization from n-hexane afforded single crystals, suitable for X-ray diffraction. Thus, the configurations, conformations, and interesting crystal packing effects have been determined unequivocally. The bicyclic skeleton consists of a lactam ring, attached by a spiro junction to a cyclohexane ring. The lactam ring adopts an envelope conformation and the cyclohexane ring has a chair conformation. The main difference between compound 1b and compound 1c is the position of the carbonyl group on the 2-pyrrolidine ring with respect to the methyl group on the 8-position of the cyclohexane ring, which is cis (1b) or trans (1c). A remarkable feature of all three compounds is the existence of a mirror plane within the molecule. Given that all compounds crystallize in centrosymmetric space groups, the packing always contains interesting enantiomer-like pairs. Finally, the structures are stabilized by intermolecular N–H···O hydrogen bonds.http://link.springer.com/article/10.1186/s13065-019-0586-72-Azaspiro[4.5]deca-1-onesCis- and trans-formConfigurationConformationLactams |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Tobias Krueger Alexandra Kelling Torsten Linker Uwe Schilde |
spellingShingle |
Tobias Krueger Alexandra Kelling Torsten Linker Uwe Schilde Crystal structures of three cyclohexane-based γ-spirolactams: determination of configurations and conformations BMC Chemistry 2-Azaspiro[4.5]deca-1-ones Cis- and trans-form Configuration Conformation Lactams |
author_facet |
Tobias Krueger Alexandra Kelling Torsten Linker Uwe Schilde |
author_sort |
Tobias Krueger |
title |
Crystal structures of three cyclohexane-based γ-spirolactams: determination of configurations and conformations |
title_short |
Crystal structures of three cyclohexane-based γ-spirolactams: determination of configurations and conformations |
title_full |
Crystal structures of three cyclohexane-based γ-spirolactams: determination of configurations and conformations |
title_fullStr |
Crystal structures of three cyclohexane-based γ-spirolactams: determination of configurations and conformations |
title_full_unstemmed |
Crystal structures of three cyclohexane-based γ-spirolactams: determination of configurations and conformations |
title_sort |
crystal structures of three cyclohexane-based γ-spirolactams: determination of configurations and conformations |
publisher |
BMC |
series |
BMC Chemistry |
issn |
2661-801X |
publishDate |
2019-05-01 |
description |
Abstract The title compounds, 2-azaspiro[4.5]deca-1-one, C9H15NO, (1a), cis-8-methyl-2-azaspiro[4.5]deca-1-one, C10H17NO, (1b), and trans-8-methyl-2-azaspiro[4.5]deca-1-one, C10H17NO, (1c), were synthesized from benzoic acids 2 in only 3 steps in high yields. Crystallization from n-hexane afforded single crystals, suitable for X-ray diffraction. Thus, the configurations, conformations, and interesting crystal packing effects have been determined unequivocally. The bicyclic skeleton consists of a lactam ring, attached by a spiro junction to a cyclohexane ring. The lactam ring adopts an envelope conformation and the cyclohexane ring has a chair conformation. The main difference between compound 1b and compound 1c is the position of the carbonyl group on the 2-pyrrolidine ring with respect to the methyl group on the 8-position of the cyclohexane ring, which is cis (1b) or trans (1c). A remarkable feature of all three compounds is the existence of a mirror plane within the molecule. Given that all compounds crystallize in centrosymmetric space groups, the packing always contains interesting enantiomer-like pairs. Finally, the structures are stabilized by intermolecular N–H···O hydrogen bonds. |
topic |
2-Azaspiro[4.5]deca-1-ones Cis- and trans-form Configuration Conformation Lactams |
url |
http://link.springer.com/article/10.1186/s13065-019-0586-7 |
work_keys_str_mv |
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1724496077151797248 |