32157-29-2Relevant articles and documents
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Block,E.,Bazzi,A.A.,Revelle,L.K.
, p. 2490 (1980)
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Discovery of overlooked enzyme in onion and its application
Kamoi, Takahiro
, p. 698 - 700 (2019/04/30)
When onions (Allium cepa) are chopped, cells are broken, propanthial S-oxide (lachrymatory factor; LF) is released and it makes our eyes water. LF had long been believed to be formed non-enzymatically from 1-propenesulfenic acid (PSA), a putative reaction product of alliinase acting on trans-(+)-S-(1-propenyl)-L-cysteine sulfoxide (1-PRENCSO). During the course of our study for the discoloration of Allium plants, however, we got a clue that some unknown enzyme responsible for the LF formation should be present in the crude onion alliinase preparation. In this study, we report the discovery of this new enzyme called lachrymatory factor synthase (LFS), and its application such as non-lachrymatory onions.
2-Thiabicyclohept-5-ene and Its S-Oxides and 3-Alkyl Derivatives: Sulfine and Sulfene Cyclopentadiene Diels-Alder Adducts. Conversion of the Cyclopentadiene-Sulfine Adducts into 2-Oxa-3-thiabicyclooct-7-enes, Novel Bicyclic Sultenes
Block, Eric,Wall, Alan
, p. 809 - 818 (2007/10/02)
Reaction of (trimethylsilyl)methanesulfonyl chloride (6a) or -sulfonic anhydride (6b) with cesium fluoride in the presence of cyclopentadiene affords 2-thiabicyclohept-5-ene 2,2-dioxide (4) by way of sulfene CH2=SO2.Similar reaction of (trimethylsilyl)methanesulfinyl chloride (7) gave unstable 2-thiabicyclohept-5-ene endo-2-oxide (3) via the intermediacy of sulfine CH2=SO.Compound 3 can be oxidized to 4 and reduced to 2-thiabicyclohept-5-ene (1) and the latter oxidized to the stable 2-thiabicyclohept-5-ene exo-2-oxide (2).Fluorodesilylation of 1-(trimethylsilyl)propanesulfonic anhydride (8) in the presence of cyclopentadiene gave a 77/23 ratio of endo/exo-3-ethyl-2-thiabicyclohept-5-ene 2,2-dioxide (9a/b) by way of propanethial S,S-dioxide.The structure of the major isomer 9a was established by an X-ray structure of the corresponding exo-epoxide 11a, formed from 9a by oxidation.Reaction of 4 with n-butyllithium followed by ethyl iodide gave a compound identical with minor isomer 9b.Reaction of propanethial S-oxide with cyclopentadiene gave unstable endo-3-ethyl-2-thiabicyclohept-5-ene endo-5-oxide (10a).The structure of 10a was established by oxidation to sulfone 9a, by reduction and reoxidation to a stable exo-5-oxide 10b, by its facile sigmatropic rearrangement to exo-4-ethyl-2-oxa-3-thiabicyclooct-7-ene (14c), and by NMR spectroscopic methods.Compound 14c was characterized by NMR spectroscopy and by its reactions.Oxidation of 14c gave the endo/exo-3-oxides 15c/15c' and the 3,3-dioxide 16c.Reaction of 14c with phenyllithium gave alcohol 17c, which was desulfurized and oxidized to 5-propyl-2-cyclopentenone or was oxidized at both carbon and sulfur to give (E)-5-propylidene-2-cyclopentenone 21c on gentle warming.Reaction of 14c with tert-butyl alcohol gave exo-6-tert-butoxy-exo-3-ethyl-syn-7-hydroxy-2-thiabicycloheptane (24), characterized by further oxidation to crystalline hydroxy sulfone 25 and keto sulfone 26.Mechanisms are proposed for the above series of reactions.
