158554-98-4

Upstream product

• 87069-72-5 (R)-N-(1-hydroxybutan-2-yl)benzamide 
• 158554-95-1 (R)-3-Benzyl-4-ethyl-1,1-dioxo-1λ⁶-thiazolidin-2-one 
• 98-88-4 benzoyl chloride 

Downstream Products

• 158555-01-2 4-ethyl-2-phenylthiazole 
• 190260-52-7 (4R)-4-ethyl-2-phenyl-4,5-dihydro-1λ⁶,3-thiazole 1,1-dioxide 
• 100-47-0 benzonitrile 

Relevant academic research and scientific papers

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

Eight new chiral 2-thiazolines (4,5-dihydro-1,3-thiazoles) 2 have been prepared by treatment of the 2-methyloxazolines 1, the benzoylamino alcohols 4 or the trimethylacetylamino alcohols 5 with P2S5. With a 2-methyl substituent, reaction with Oxone results in ring-opening to give the acetylamino disulfides 9 and with MCPBA there is also ring-opening with incorporation of a m-chlorobenzoyl group to give 12. Treatment of the 2-phenyl compounds with a variety of oxidants gives the benzoylamino sulfonic acids 10 and the disulfides 9 together with the thiazoles 11 in varying proportions. The sulfonic acids and thiazoles are obtained in pure form by reaction with 3 equiv. of peracetic acid and with sulfur, respectively. Although reaction of 2d-f with KMnO4 under phase-transfer conditions gives the thiazoles 11, addition of 1 equiv. of benzoic acid results in a complete change in selectivity to afford the thiazoline 1,1-dioxides 3d-f in excellent yield. These compounds prove to be exceptionally moisture-sensitive and readily hydrolyse to give the benzoylamino sulfinic acids 8 whose further oxidation and disproportionation probably explains the formation of the sulfonic acids and disulfides with the other oxidants. The high reactivity of the sulfones 3 towards nucleophilic ring-opening precludes their deprotonation and alkylation. Upon flash vacuum pyrolysis at 600°C, they fragment to give SO2, benzonitrile and the alkenes 16 in high yield. Fully assigned 13C NMR spectra are presented for the 18 heterocyclic compounds prepared and for 17 acyclic derivatives.

Synthesis and pyrolytic behaviour of thiazolidin-2-one 1,1-dioxides

Four examples of the chiral thiazolidin-2-one 1,1-dioxides 5 have been prepared by reaction of the appropriate amino alcohols 11 with CS2 in aqueous sodium hydroxide to give the thiazolidine-2-thiones 12, followed by oxidation with KMnO4 under phase-transfer conditions in the presence of benzoic acid, either directly or via the thiazolidin-2-ones 13. Upon flash vacuum pyrolysis (FVP) at 650°C, 5a-c decompose mainly by loss of SO2 to give an alkene and benzyl isocyanate together with other products from fragmentation of the N-benzyl group. A significant minor pathway involves net loss of CO2 and water to give the 2-phenyl-4,5-dihydrothiazoles 21 together with their aromatisation products 22 and 23. A mechanism for this new heterocyclic transformation is proposed involving initial expansion to a cyclic carbamic-sulnnic anhydride (2,1,4-oxathiazin-3-one 1-oxide). The fully assigned 13C NMR spectra are presented for 5, 12 and 13 and the 33S NMR spectrum has been obtained for 5c.