Synthesis of some thiochromeno 4,3-c - and 3,4-c -pyrazoles
Synthesis of some thiochromeno 4,3-c - and 3,4-c -pyrazoles
Reaction of 3-hydroxymethylene- and 3-cyanomethylene-thiochroman-4-ones with various hydrazine derivatives affords 4H-thiochromeno[4,3-c]pyrazoles. The novel isomeric thiochromeno[3,4-c]pyrazoles result when 4-(dimethylaminomethylene)thiochroman-3-ones react with methyl- and phenyl-hydrazines. Acidic hydrolysis of 3-(dimethylhydrazonoethylidene)-2,2,6-trimethylthiochroman-4-one yields the 3-cyanomethylenethiochroman-4-one. Formation of 6-chloro-3-hydroxymethylenethiochroman-4-one is accompanied by a thiochroman-3-yl(oxothiochromen-3-yl)methane derivative produced through a rearrangement-carbocation interception sequence. A 3-isopropenylthiochromenone, obtained by the acid promoted rearrangement of a 3-hydroxymethylenethiochroman-4-one, undergoes Diels-Alder cycloadditions to provide a new route to thioxanthenones.
cyclic beta-enaminones, substituted pyrazoles, fused heterocycles, stereochemistry, ketones, reactivity
2930-2938
Gabbutt, C. D.
94192b7e-b99b-4611-943e-fe645f2d6a52
Hepworth, J. D.
8415acca-48d0-4964-83a5-acd903afd3d4
Heron, B. M.
64aef16b-7be8-40ee-980c-74f4169f8057
Coles, S. J.
503a9d9c-0380-4fcd-ad31-cd329255c08e
Hursthouse, M. B.
57a2ddf9-b1b3-4f38-bfe9-ef2f526388da
2000
Gabbutt, C. D.
94192b7e-b99b-4611-943e-fe645f2d6a52
Hepworth, J. D.
8415acca-48d0-4964-83a5-acd903afd3d4
Heron, B. M.
64aef16b-7be8-40ee-980c-74f4169f8057
Coles, S. J.
503a9d9c-0380-4fcd-ad31-cd329255c08e
Hursthouse, M. B.
57a2ddf9-b1b3-4f38-bfe9-ef2f526388da
Gabbutt, C. D., Hepworth, J. D., Heron, B. M., Coles, S. J. and Hursthouse, M. B.
(2000)
Synthesis of some thiochromeno 4,3-c - and 3,4-c -pyrazoles.
Journal of the Chemical Society, Perkin Transactions 1, (17), .
(doi:10.1039/b004149l).
Abstract
Reaction of 3-hydroxymethylene- and 3-cyanomethylene-thiochroman-4-ones with various hydrazine derivatives affords 4H-thiochromeno[4,3-c]pyrazoles. The novel isomeric thiochromeno[3,4-c]pyrazoles result when 4-(dimethylaminomethylene)thiochroman-3-ones react with methyl- and phenyl-hydrazines. Acidic hydrolysis of 3-(dimethylhydrazonoethylidene)-2,2,6-trimethylthiochroman-4-one yields the 3-cyanomethylenethiochroman-4-one. Formation of 6-chloro-3-hydroxymethylenethiochroman-4-one is accompanied by a thiochroman-3-yl(oxothiochromen-3-yl)methane derivative produced through a rearrangement-carbocation interception sequence. A 3-isopropenylthiochromenone, obtained by the acid promoted rearrangement of a 3-hydroxymethylenethiochroman-4-one, undergoes Diels-Alder cycloadditions to provide a new route to thioxanthenones.
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Published date: 2000
Keywords:
cyclic beta-enaminones, substituted pyrazoles, fused heterocycles, stereochemistry, ketones, reactivity
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Local EPrints ID: 18868
URI: http://eprints.soton.ac.uk/id/eprint/18868
ISSN: 0300-922X
PURE UUID: b8ad6a49-0385-43de-b326-50d1b971eac3
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Date deposited: 21 Dec 2005
Last modified: 15 Mar 2024 06:08
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Author:
C. D. Gabbutt
Author:
J. D. Hepworth
Author:
B. M. Heron
Author:
S. J. Coles
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