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Synthesis of Six‐ to Nine‐Membered Ring Oximinoorthodithiolactones by Cyclization of Nitroketene S , S ‐Acetals in Trifluoromethanesulfonic Acid
Author(s) -
Coustard JeanMarie
Publication year - 2001
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200104)2001:8<1525::aid-ejoc1525>3.0.co;2-o
Subject(s) - chemistry , ring (chemistry) , methanol , intramolecular force , nitro , medicinal chemistry , nuclear magnetic resonance spectroscopy , quenching (fluorescence) , stereochemistry , organic chemistry , fluorescence , alkyl , physics , quantum mechanics
2‐Nitro‐1,1‐bis(phenylalkylthio)ethene or 1‐(methylthio)‐2‐nitro‐1‐(phenylalkylthio)ethene derivatives tethered to an aromatic ring undergo a fast intramolecular cyclization in trifluoromethanesulfonic acid, with the intermediate formation of dications, which can be detected by NMR spectroscopy. Quenching with methanol at low temperature affords cyclic orthothioesters of isothiochromanones, 4,5‐dihydrobenzo[ d ]thiepin‐1‐one, 5,6‐dihydro‐4 H ‐benzo[ d ]thiocin‐1‐one and 8,9,10,11‐tetrahydro‐7‐thiabenzocyclononen‐5‐one oximes. The yields are usually fair to good, except for the nine‐membered ring derivatives.