Synthesis and oxidation of chiral 2-thiazolines (4,5-dihydro-1,3-thiazoles)

Aitken, R. A.; Armstrong, D. P.; Galt, R. H. B.; Mesher, S. T. E.

doi:10.1039/a605539g

Cited by 26 publications

(20 citation statements)

References 8 publications

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“…We started by converting the two readily available chiral oxazolines 5a and 5b, prepared by reaction of ethyl acetimidate hydrochloride with (S)-phenylalaninol and (S)valinol respectively, 5 into the corresponding Nmethyloxazolinium salts 6a and 6b. Treatment with iodomethane in THF at room temperature in the dark gave the required salts in low to moderate yield as colourless crystals (Scheme 3).…”

Section: Methodsmentioning

confidence: 99%

Generation and hydrolysis of N-acyloxazolinium salts allowing regiospecific acylation of chiral amino alcohols

Aitken

Slawin

Wilson

2020

Chem Heterocycl Comp

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In an attempt to form 2-alkylidene-1,3-oxazolidines, chiral 2-oxazolines have been N-alkylated and N-acylated. Two new Nmethyloxazolinium salts have been prepared and characterised but base treatment resulted in their decomposition. In contrast, attempts to isolate three N-benzoyloxazolinium salts gave the products of their ring hydrolysis: unsymmetrically diacylated amino alcohols whose structure was confirmed by x-ray diffraction in one case. Overall the method allows stepwise regiospecific N,O-diacylation of 1,2-amino alcohols.

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Section: Methodsmentioning

confidence: 99%

Generation and hydrolysis of N-acyloxazolinium salts allowing regiospecific acylation of chiral amino alcohols

Aitken

Slawin

Wilson

2020

Chem Heterocycl Comp

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“…1b [11] : 1 H-NMR: δ 7.96–7.91(m, 2H, ArH), 7.44–7.37 (m, 3H, ArH), 6.86 (s, 1H), 3.21–3.11 (m, 1H), 1.35 (d, J = 6.90 Hz, 6H); 13 C-NMR: δ 167.29, 164.87, 134.08, 129.63, 128.79, 126.52, 110.88, 31.05, 22.40.…”

Section: Methodsmentioning

confidence: 99%

“…Another efficient method is the introduction of substitutions onto a thiazole core structure through Stille coupling [9], which involves the use of organostannane intermediates. In recent years, a new and frequently encountered method for thiazole synthesis is the conversion of thiazoline derivatives through the use of dehydrogenating reagents such as sulfur [10], KMnO 4 [11], Cu(I)/Cu(II)/peroxide oxidation [12], MnO 2 [13,14,15,16], NaH/DBU [17], and so on. Among these dehydrogenating reagents, activated MnO 2 is a very simple and convenient reagent for the synthesis of thiazoles from thiazolines.…”

Section: Introductionmentioning

confidence: 99%

A Facile Synthesis of 2,4-Disubstituted Thiazoles Using MnO2

Chen

Wang

et al. 2009

Molecules

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“…1 In no case was N-oxidation observed. On the other hand, 2-oxazolines (4,5-dihydrooxazoles) are known to undergo oxidation to the corresponding oxaziridines with MCPBA and these may be isomerised to the corresponding oxazoline N-oxides on silica gel.…”

Section: Introductionmentioning

confidence: 99%

“…2 The 4,4-dimethyloxazoline N-oxides formed in this way or by an alternative ring synthesis have been shown to be effective 1,3-dipoles. 3 Since we had available a range of chiral 4-substituted oxazolines used as precursors for the corresponding thiazolines, 1 we decided to examine oxidation of these in the hope that the Noxides might prove to be useful chiral 1,3-dipoles for asymmetric synthesis. In this paper the results of oxidation of the representative oxazoline 1 with both MCPBA and the more unusual oxidant NO 2 are described.…”

Section: Introductionmentioning

confidence: 99%