- Nitrile Sulphides. Part 5. 1,3-Dipolar Cycloaddition of p-Methoxybenzonitrile Sulphide to Imines and Crystal Structure of One of the Resulting 4,5-Dihydro-1,2,4-thiadiazoles
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p-Methoxybenzonitrile sulphide, generated by thermal fragmentation of the corresponding 1,3,4-oxathiazol-2-one, undergoes 1,3-dipolar cycloaddition to imines forming 4,5-dihydro-1,2,4-thiadiazoles.X-ray crystal structure analysis shows that the heterocyclic ring is non-planar with a fold of 30 deg about the S(1) - N(4) vector.
- Gould, Robert O.,Paton, Michael R.,Ross, John F.,Walkinshaw, Malcolm D.,Crosby, John
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p. 1372 - 1396
(2007/10/02)
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- Nitrile Sulphides. Part 3. Thermal Fragmentation of 1,3,4-Oxathiazoles: Formation of Nitrile Sulphides in a Retro-1,3-dipolar Cycloaddition Reaction
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On thermolysis at ca. 160 gradC 1,3,4-oxathiazoles undergo retro-1,3-dipolar cycloaddition forming nitrile sulphides and carbonyl-containing fragments.The nitrile sulphides either decompose to sulphur and nitriles or are trapped as their 1,3-dipolar cycloadducts in the presence of dipolarophiles (dimethyl acetylenedicarboxylate, ethyl cyanoformate, benzonitrile, ethyl propiolate).Similar ratios (1.32, l.34, 1.33, 1.31) of 4- and 5-ethoxycarbonyl-3-(p-methoxyphenyl)isothiazole obtained from four sources of p-methoxybenzonitrile sulphide with ethyl propriolate provide strong evidence for product formation from a discrete intermediate nitrile sulphide rather than via direct interaction of precursor with dipolarophile. 2-Dichloromethylene-1,3,4-oxathiazoles, prepared by dehydrochlorination of 2-trichloromethyloxathiazoles, prepared by dehydrochlorination of 2-trichlorometyloxathiazoles, likewise fragment to nitrile sulphides, but attempts to trap dichloroketene were unsuccessful.
- Paton, R. Michael,Robertson, Fiona M.,Ross, John F.,Crosby, John
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p. 1517 - 1522
(2007/10/02)
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- THE THERMAL FRAGMENTATION OF 1,3,4-DITHIAZOL-2-ONES
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Thermal expulsion of carbon oxysulphide from 1,3,4-dithiazol-2-ones in the presence of DMAD affords nitrile sulphide-derived dimethyl isothiazole-4,5-dicarboxylates.
- Greig, Derek J.,Paton, R. Michael,Rankin, John G.,Ross, John F.,Crosby, John
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p. 5453 - 5454
(2007/10/02)
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- Nitrile Sulphide Formation from the Thermal Fragmentation of 1,3,4-Oxathiazoles: a Retro-1,3-dipolar Cycloaddition
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1,3,4-Oxathiazoles, on thermolysis, undergo retro-1,3-dipolar cycloaddition to afford carbonyl compounds and nitrile sulphides, which may be trapped by cycloaddition with alkynes and nitriles.
- Paton, R. Michael,Robertson, Fiona M.,Ross, John F.,Crosby, John
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p. 714 - 715
(2007/10/02)
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