Rearrangements of penicillin sulphoxides

Barton, D. H. R.; Comer, F.; Greig, D. G. T.; Lucente, Gino; Sammes, Peter G.; Underwood, W. G. E.

doi:10.1039/c29700001059

Cited by 22 publications

(3 citation statements)

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“…The organic layer was washed at 0 °C with water (2 x 100 mL), dried (Na2S04), filtered, and evaporated. Addition of MeOH (50 mL) to the light yellow oil caused the crystallization of 4b in two fractions: 2.01 g (46% yield); mp 152 °C dec; R¡ (C6H6-Me2CO, 4:1) 0.57; IR (KBr) Vwa 3400, 3370, 1685, 1510 (amide), 1782 (d-lactam), 1745,1208 (ester), 1030 (S=0), 700 (phenyl) cm '1; NMR (CDClj, Me4Si) 1.03 (s, CH3), 1.61 (s, CH3), 3.52 (s, CH2CO), 4.61 (s, 3-H), 4.91 (s, 5-H), 5.19 (AB, CH2C6H5) 7.10 (s, CONH, partial deuteration), 7.25 (s, C6H6), 7.31 (s, C6H5). The product also contained deuterium in the amide function as deduced from the mass spectrum.…”

Section: Methodsmentioning

confidence: 99%

Preparation of 6-deuteriopenicillins

Claes¹,

Roets²,

Herdewijn³

et al. 1981

J. Org. Chem.

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When penicillin (S)-S-oxide esters are treated with triethylamine and acetonitrile containing DzO, both epimerization and deuteration at the 6-position occurs. This reaction is found to be a convenient method for the preparation of 6-deuteriopenicillins. 6-Deuteriobenzylpenicillin (S)-S-oxide benzyl ester (containing more than 95% D in the 6-position) was obtained from the (S)-S-oxide of penicillin G benzyl ester. Deoxygenation of the sulfoxide followed by catalytic debenzylation gave penicillin G deuterated in the 6-position. A kinetic study of deuterium incorporation and epimerization at C-6 was carried out for the (S)-S-oxide of penicillin V benzyl ester and for its 6-epimer. Deuteration was found to be faster than epimerization when the sulfoxide with the natural configuration was used as starting material. In the experiment starting with the 6-epimer, epimerization is faster than deuteration. A revised mechanism for the epimerization and deuteration of penicillin S-oxide esters is proposed.

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Section: Methodsmentioning

confidence: 99%

Preparation of 6-deuteriopenicillins

Claes¹,

Roets²,

Herdewijn³

et al. 1981

J. Org. Chem.

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“…The formation of the subproduct 10 can be explained by addition of in situ formed phenyl sulfenic acid to the enoate. The addition of sulfenic acids to unsaturated esters have been demonstrated previously. − Compound 10 would be formed in a low yield due to the high tendency of sulfinyl radicals (or sulfenic acids) to afford thiosulphonates, although final reaction yields would depend on the subtle interplay between kinetics and thermodynamics of each elementary step depicted in Scheme .…”

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confidence: 89%

Radical Mechanism in the Elimination of 2-Arylsulfinyl Esters

et al. 2012

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Abstract-The mechanism of the dehydrosulfenylation of 2-arylsulfinyl esters was investigated. The reaction was found to follow a homolytic cleavage mechanism as verified by electrospray ionization tandem mass spectrometry and experimental work. Rearranged sulfoxides are obtained as by-products during the elimination reaction. _______________________________________________________________________________________________________________Elimination reactions of sulfoxides and sulfones are well known reactions in synthetic organic chemistry.

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“…Sulfoxide-Sulfenic Acid Equilibrium It was soon found that the (fl)-sulfoxides (e.g., 24) were very unstable to heat, rapidly reverting to the thermodynami- cally more stable S isomers.31,37 Evidence for the formation of a sulfenic acid in this reaction was first obtained by heating the (fl)-sulfoxide 24 in the presence of deuterated fe/t-butyl alcohol. 39 The product was the corresponding (S)-sulfoxide in which only one atom was incorporated (Scheme IV) into the 28-methyl group, i.e., cis to the resultant sulfoxide bond. Under identical conditions, no incorporation was observed for the (S)-sulfoxide.…”

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confidence: 99%