- Title
- Corrigendum to “A multicomponent access to 1,3-thiazine-6-phenylimino-5-carboxylates” [Tetrahedron Lett. 57 (2016) 3256–3259]
- Creator
- Trinh, Trieu N.; McCluskey, Adam
- Relation
- Tetrahedron Letters Vol. 59, Issue 32, p. 3155-3156
- Publisher Link
- http://dx.doi.org/10.1016/j.tetlet.2018.07.018
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2018
- Description
- In recent studies on the multicomponent route described in our original submission [1], we gained access to crystalline material suitable for X-ray analysis (Scheme 1). This revealed that our original structural assignment based on NMR, IR and MS evidence was incorrect. The product arising from the multicomponent reaction of ethyl 3-aminocrotonate (1), phenylisothiocyanate (2) and acetic anhydride (3) was not ethyl (Z)-2,4-dimethyl-6-(phenylimino)-6H-1,3-thiazine-5-carboxylate (5), but the thioamide isomer, ethyl 2,4-dimethyl-1-phenyl-6-thioxo-1,6-dihydropyrimidine-5-carboxylate (7) (Scheme 1 and insert). The structure of thioamide (7), and related analogues, is consistent with the NMR and IR data presented in our original submission. Using the compound numbering from the original manuscripts, analogues 8a–l, are the equivalent thioamides as shown in Table 1. Re-examination of the reaction mechanism based on this data supports a N to S anion resonance with the charge intercepted by acetic anhydride at the nitrogen anion stage [1], [2]. As previously proposed, ensuing acetate loss and H-abstraction affords the ene-amine 9 which effects an intramolecular condensation with the N-acyl carbonyl moiety. Loss of water and acetate removal of the proton yields ethyl 2,4-dimethyl-1-phenyl-6-thioxo-1,6-dihydropyrimidine-5-carboxylate (Scheme 2). This mechanism differs only in the interception of the nitrogen anion rather than the sulfur anion by acetic anhydride, but this re-working is necessitated by the structure confirmed herein by X-ray crystallography. We regret any inconvenience this may have caused readers and sincerely apologize for this error.
- Subject
- multicomponent route; crystalline material; x-ray analysis; data
- Identifier
- http://hdl.handle.net/1959.13/1447379
- Identifier
- uon:43130
- Identifier
- ISSN:0040-4039
- Language
- eng
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