Synthesis of imidazo[5,1-b]thiazoles or spiro-β-lactams by reaction of imines with mesoionic compounds or ketenes generated from N-acyl-thiazolidine-2-carboxylic acids

Cremonesi, Giuseppe; Croce, Piero Dalla; Rosa, Concetta La

doi:10.1016/j.tet.2003.10.093

Cited by 32 publications

(7 citation statements)

References 16 publications

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“…B1 and C1 upon rearrangement could form B2 and C2 which upon subsequent removal of water molecule transform to the spirocyclic β‐lactams trans ‐ 6 and cis ‐ 6′ . The observed diastereoselectivity (2 : 1) of 6 and 6′ with mercaptoacetic acid 5 a and 2‐mercaptopropionic acid 5 b could be attributed to the presence of sulfur which could favour the generation of thermodynamically more stable five‐membered spiro products trans ‐ 6 as a result of steric factors; less steric encumbrance between syn sulphur (at C4) and phenyl / aryl groups (at C3) (in five‐membered spiro adducts), which is well in accordance with the literature report [45] . However, with 3‐mercaptopropionic acid 5 c , the preferred mode of attack of thiol group is from Re face (α‐face).…”

Section: Resultssupporting

confidence: 91%

“…As is clear from diastereomeric ratio (dr), delivery of 5 f to the sterically less hindered α‐face predominates forming spiro‐fused β‐lactams trans ‐ 6 as the major products. The greater stability of five‐membered spiro adducts trans ‐6 incorporating sulfur (at C3 spiro centre) and aryl substituent (at C2) in a syn relationship to each other is well supported by the literature report [45] …”

Section: Resultssupporting

confidence: 60%

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Synthesis of α‐Heterocycle Anchored Spirocyclic Azetidin‐2‐ones in a Minute by p‐TSA Catalyzed Cyclocondensation of Azetidin‐2,3‐diones with Difunctionalized Substrates

et al. 2021

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Monocyclic azetidin‐2,3‐diones provide easy extensions to spiro‐fused azetidin‐2‐ones upon p‐toluenesulfonic acid (p‐TSA) catalyzed cyclocondensation reaction with difunctionalized substrates [mercaptoacids (mercaptoacetic acid, 2‐mercaptopropionic acid, 3‐mercaptopropionic acid), ethan‐1,2‐dithiol, ortho‐difunctionalized benzenes (ortho‐phenylenediamine, ortho‐aminothiophenol)]. 1,3‐Oxathiolan‐5‐one/6‐one, 1,3‐dithiolane, 2,3‐dihydrobenzo[d]imidazole and 2,3‐dihydrobenzo[d]thiazole tethered spirocyclic azetidin‐2‐ones were obtained in good overall isolated yields (69–89 %) in a very short‐time duration (max 1 min) using toluene Dean‐Stark reflux/dichloromethane rt stirring conditions. The stereochemical and spectral studies, stabilities and diastereoisomeric ratio for trans and cis spiro‐fused products are reported. The trans and cis configuration has been assigned to spiro‐β‐lactams wrt the stereochemical relationship between sulfur atom (at spiro centre) and the vicinal methine hydrogen atom at C3/C2. The absolute configuration of one trans 1,3‐oxathiolan‐5‐one fused spirocyclic azetidin‐2‐one was clearly identified by X‐ray single crystal structure analysis.

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Section: Resultssupporting

confidence: 91%

Section: Resultssupporting

confidence: 60%

Synthesis of α‐Heterocycle Anchored Spirocyclic Azetidin‐2‐ones in a Minute by p‐TSA Catalyzed Cyclocondensation of Azetidin‐2,3‐diones with Difunctionalized Substrates

et al. 2021

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“…These compounds are mostly synthesized by cycloaddition to an exocyclic bond. Several syntheses of spiro-β-lactams have been reported [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ]. Polycyclic aromatic β-lactams have shown anticancer and other biological activities [ 43 , 44 , 45 ].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Some New Mono- and Bis-Polycyclic Aromatic Spiro and Bis-Nonspiro-β-Lactams

Jarrahpour

Ebrahimi

2010

Molecules

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Some new mono-and bis-polycyclic aromatic spiro-β-lactams and bis-non spiro-polycyclic aromatic β-lactams have been synthesized from imines derived from anthracene-9-carbaldehyde, 2-naphtaldehyde and a ketene derived from 9H-xanthene-9-carboxylic acid and phenoxyacetic acid by a [2+2] cycloaddition reaction. The cycloadducts were characterized by spectral data, including 1H-NMR, 13C-NMR, IR and elemental analyses. The configurations of some of these mono-spiro-β-lactams were established by X-ray crystal analysis.

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“…We have previously described our studies of the synthesis and reactivity of heterocyclic spiro-β-lactams. In particular, we were interested in producing various substituted 4-spiro-β-lactams by means of a Staudinger reaction between imines and nonsymmetrical cyclic ketenes generated from cyclic N -acyl α-amino acids.…”

Section: Introductionmentioning

confidence: 99%

Enantiomerically Pure Polyheterocyclic Spiro-β-lactams from trans-4-Hydroxy-l-proline

Cremonesi¹,

Croce

Fontana

et al. 2010

J. Org. Chem.

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The "Staudinger ketene-imine reaction" between ketenes generated from natural O,N-protected trans-4-hydroxy-l-prolines and the N-benzyl-N-benzylideneamine led to mixtures of diastereoisomeric, enantiomerically pure pyrrolidine-derived spiro-beta-lactams with a relative cis configuration. These were transformed into the corresponding pyrroline-spiro-beta-lactams by means of treatment with a base and the new C=C double bond was submitted to a number of different reactions in order to evaluate its reactivity and obtain new polyheterocyclic enantiomerically pure spiro-beta-lactams.

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Synthesis of imidazo[5,1-b]thiazoles or spiro-β-lactams by reaction of imines with mesoionic compounds or ketenes generated from N-acyl-thiazolidine-2-carboxylic acids

Cited by 32 publications

References 16 publications

Synthesis of α‐Heterocycle Anchored Spirocyclic Azetidin‐2‐ones in a Minute by p‐TSA Catalyzed Cyclocondensation of Azetidin‐2,3‐diones with Difunctionalized Substrates

Synthesis of α‐Heterocycle Anchored Spirocyclic Azetidin‐2‐ones in a Minute by p‐TSA Catalyzed Cyclocondensation of Azetidin‐2,3‐diones with Difunctionalized Substrates

Synthesis of Some New Mono- and Bis-Polycyclic Aromatic Spiro and Bis-Nonspiro-β-Lactams

Enantiomerically Pure Polyheterocyclic Spiro-β-lactams from trans-4-Hydroxy-l-proline

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