Zur Kenntniss der Ketene. Diphenylketen

Staudinger, H.

doi:10.1002/jlac.19073560106

Cited by 552 publications

(269 citation statements)

References 45 publications

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“…1750 cm -1 , i.e., the characteristic β-lactam C=O stretching band. In both compounds, an amide/lactam group was indicated by IR absorptions at 1700 and 1720/1710 cm -1 , respectively, and 13 C-NMR signals at 163.9 and 159.5 ppm, respectively. On the basis of the specroscopic data, structures 7a and 8 were proposed for these products (Scheme 3).…”

Section: Methodsmentioning

confidence: 96%

“…Since its discovery by Staudinger in 1907 [13], the scope and limitations of this method have been studied extensively, and much progress has been made on the synthesis of monocyclic β-lactams [14]. However, for the synthesis of bicyclic β-lactams, e.g., penams, this method suffers in two ways: the poor yield of the reaction and the low or inappropriate stereoselectivity.…”

mentioning

confidence: 99%

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Reactions of Acid Chlorides/Ketenes with 2‐Substituted 4,5‐Dihydro‐4,4‐dimethyl‐1,3‐thiazoles: Formation of Penam Derivatives

Shi

Linden

Heimgartner

2013

Helvetica Chimica Acta

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Addition reactions of acid chlorides with various 2-substituted 4,5-dihydro-4,4-dimethyl-5-(methylsulfanyl)-1,3-thiazoles under basic conditions were studied. Two kinds of products were obtained from these additions, beta-lactams and non-beta-lactam adducts. When the reaction was carried out with 4,5-dihydro-1,3-thiazoles with a Ph substituent at C(2), the reaction proceeded via formal [2+2] cycloaddition and led to the correspoding beta-lactam. On the other hand, acid chlorides and 4,5-dihydro-1,3-thiazoles bearing an alpha-H-atom at the C(2)-substituent underwent C(alpha)-and/or N-addition reactions and furnished non-beta-lactam adducts, i.e., C(alpha)-and/or N-acylated 1,3-thiazolidines. The attempted transformations of sulfonyl esters of exo-6-hydroxy penams to endo-6-azido penams failed, although they were successful with mono-beta-lactams under the same conditions.

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Section: Methodsmentioning

confidence: 96%

mentioning

confidence: 99%

Reactions of Acid Chlorides/Ketenes with 2‐Substituted 4,5‐Dihydro‐4,4‐dimethyl‐1,3‐thiazoles: Formation of Penam Derivatives

Shi

Linden

Heimgartner

2013

Helvetica Chimica Acta

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“…Already in 1907, Hermann Staudinger discovered their [2 + 2] cycloadditions with ketenes to give β -lactams (Scheme 1) [11]. In 1950 Corey et al utilized this cycloaddition reaction for the first laboratory synthesis of penicillin [12].…”

Section: Introductionmentioning

confidence: 99%

Nucleophilic Reactivities of Schiff Bases

Maji

Mayr

2013

Zeitschrift Für Naturforschung B

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The nucleophile-specific parameters N and s N , as defined by the linear free energy relationship log k = s N (N + E) (J. Am. Chem. Soc. 2001, 123, 9500 -9512), were determined for five imines 1a-e by studying the kinetics of their reactions with benzhydrylium ions in dichloromethane solution at 20 • C. These parameters allowed us to include representative Schiff bases into our comprehensive nucleophilicity scale and compare their reactivities with those of other N-nucleophiles.

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“…Although there are many methods known for the construction of the β-lactam rings, the Staudinger reaction is still the most frequently used and is considered to be the most effective. This paper describes for the first time the synthesis of a trans β-lactam with polyaromatic imine and identifies a new stereochemical aspect of the Staudinger reaction [5]. The formation of the cis and trans β-lactams by consideration of a number of factors has been reported.…”

Section: Introductionmentioning

confidence: 99%