Results 131 to 140 of about 4,314 (176)

Rearrangements of penicillanic acid derivatives

Tetrahedron, 1975
exaly   +2 more sources

Mechanism of epimerisation of penicillanic acid derivatives

Journal of the Chemical Society, Chemical Communications, 1977
Under basic conditions, methyl benzyl-5-epipenicillinate 1,1-dioxide (6, X = SO2, R = NH.CO.CH2Ph) undergoes epimerisation at positions 6 and 3, giving the sulphones (7; X = SO2, R = NH.CO.CH2Ph) and (10), and β-elimination to yield (3R,4R)-1-(1-methoxycarbonyl-1-methylprop-1-enyl)-3-phenylacetamidoazetidin-2-one-3-sulphinic acid (9; X = SO2H).
Chandra M. Pant, Richard J. Stoodley
openaire   +1 more source

A novel rearrangement of a penicillanic acid derivative

Journal of the Chemical Society D: Chemical Communications, 1970
Triethylamine in chloroform triggers the rearrangement of methoxymethyl 6β-p-nitrobenzylideniminopenicillanate to methoxymethyl 2,3,4,7-tetrahydro-2,2-dimethyl-6-p-nitrobenzylidenimino-7-oxo-1,4-thiazepine 3(S)-carboxylate, which rearranges further to the triethylamine salt of 3-(1-carboxy-2-methylprop-1-enyl)-2,3-dihydro-5-p-nitrobenzylidenimino-6-oxo-
J. R. Jackson, R. J. Stoodley
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Photochemical transformations of 6-Amino-penicillanic acid and phenoxymethylpenicillin

Experientia, 1967
Bei der Bestrahlung von 6-Aminopenicillansaure mit UV-Licht entstehen Aminomethylpenicillin (Id), N-Formylpenicillamin (II) und ein Stoff der Summenformel C5H9NS, der vermutlich Struktur III besitzt. Phenoxymethylpenicillin wird bei der UV-Bestrahlung in ein Gemisch vonp- undo-Hydroxybenzylpenicillin umgewandelt.
W O, Godtfredsen, W, von Daehne, S, Vangedal   +2 more
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γ-Lactam analogues of penicillanic and carbapenicillanic acids

Tetrahedron, 1984
Abstract Synthesis and biological activity of γ-lactam analogues of penicillanic and carboapenicillanic acids, and the sodium periodate mediated rearrangement of pyrrolidine-2,3-diones are described. 1,3- Dipolar addition of cyclic nitrone (6) and methyl acrylate afforded the bicyclic adducts (7a) and (7b).
Jack E. Baldwin, Ming Fai Chan, Gerard Gallacher, Masami Otsuka, Peter Monk, Keith Prout   +5 more
openaire   +1 more source

6-(Methoxymethylene)penicillanic acid: a new .beta.-lactamase inactivator

Journal of Organic Chemistry, 1985
exaly   +2 more sources

γ-Lactam analogues of penicillanic and carbapenicillanic acids

J. Chem. Soc., Chem. Commun., 1983
Synthesis and biological activity of γ-lactam analogous (1) and (2) of carbapenicillanic and penicillanic acid, respectively, are described.
Jack E. Baldwin, Ming Fai Chan, Gerard Gallacher, Peter Monk, Keith Prout   +4 more
openaire   +1 more source

Enlargement of the thiazolidine ring of penicillanic acid derivatives

Journal of the Chemical Society D: Chemical Communications, 1970
6β-Phthalimidopenicillanoylchloromethane undergoes a base-promoted rearrangement to a mixture of 4-isopropylidene-3-oxo-7β-and 4-isopropylidene-3-oxo-7α-phthalimidocepham.
B. G. Ramsay, R. J. Stoodley
openaire   +1 more source

The chemistry of penicillanic acids. Part III. A route to 1,2-secopenicillins

Journal of the Chemical Society, Perkin Transactions 1, 1975
Treatment of 6β-(triphenylmethylamino)penicillanates with certain alkylating agents in the presence of strong anhydrous bases causes S-alkylation and cleavage of the thiazolidine ring between the sulphur atom and C-2. The scope and possible mechanism of the reaction are discussed.
E G, Brain, I, McMillan, J H, Nayler, R, Southgate, P, Tolliday   +4 more
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ChemInform Abstract: Cyclic Sulfamidite Analogues of Penicillanic Acid.

ChemInform, 1990
AbstractD‐(‐)‐Penicillamine (I) is subjected to cyclocondensation with glycolaldehyde (II) in hot aqueous methanol to form the diastereomeric thiazolidines (III) and (IV) which are converted into the benzylic esters (VI) and (VII) via the corresponding cesium salts.
B. K. CUTHBERT, G. LOWE
openaire   +1 more source