- Addition-substitution reactions of 2-thio-3-chloroacrylamides with carbon, nitrogen, oxygen, sulfur and selenium nucleophiles
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Synthetically versatile conjugate addition of a range of carbon, nitrogen, oxygen, sulfur and selenium nucleophiles to the highly functionalised 2-thio-3-chloroacrylamides is described. The stereochemical and synthetic features of this transformation are discussed in detail. In most instances, the nucleophile replaces the chloro substituent with retention of stereochemistry. With the oxygen nucleophiles, a second addition can occur leading to acetals, while with the nitrogen nucleophiles, E-Z isomerism occurs in the resulting enamine derivatives. The ratio of the E/Z isomers can be rationalised on the basis of the substituent and the level of oxidation.
- Kissane, Marie,Murphy, Maureen,O'Brien, Elisabeth,Chopra, Jay,Murphy, Linda,Collins, Stuart G.,Lawrence, Simon E.,Maguire, Anita R.
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supporting information; experimental part
p. 2452 - 2472
(2011/05/11)
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- New synthesis of carboxin and oxycarboxin pesticides: application to the preparation of their new analogues substituted at the C-2 methyl group
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A new synthesis of carboxin 1a and its 4,4-dioxide derivative, oxycarboxin 2a, has been devised via N-bromosuccinimide-promoted oxidative rearrangement of acetoacetanilide 1,3-oxathiolane 3.The replacement of N-bromosuccinimide with molecular bromine leads to the formation, from compound 3, of a C-2 bromomethylcarboxin derivative 1b.The latter is conveniently exploited to prepare a new class of carboxins and oxycarboxins (after oxidation of the sulfur) substituted at the C-2 methyl, by replacement of the bromine atom with various nucleophiles.
- Caputo, Romualdo,Ferreri, Carla,Guaragna, Annalisa,Palumbo, Giovanni,Pedatella, Silvana
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p. 1971 - 1974
(2007/10/02)
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- CONVERSION OF DIHYDRO-1,4-OXATHIIN-3-CARBOXAMIDE TO THE ISOMERIC DIHYDRO-1,4-OXATHIIN-2-CARBOXAMIDE
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The preparation of isomeric dihydro-1,4-oxathiin (3) from the dihydro-1,4-oxathin (1) via dichloro-1,4-oxathiane (4) is described.Chlorination of 1 followed by treatment of the resulting dichloride (4) with aqueous acetone gave dihydroxy-1,4-oxathiin (5).The solvolysis to produce intermediate chlorohydrin (11) was favored relative to elimination reaction to give exomethylene compound (8).Dehydration of 5 followed by reduction afforded α-hydroxy-1,3-oxathiolane (2) which is a key compound to prepare the isomeric dihydro-1,4-oxathiin (3).The reason for more facile displacement of chlorine at C-2 in comparison with that at C-4 in 4 was also discussed.
- Hahn, Hoh-Gyu,Chang, Kee-Hyuk,Lee, Wha Suk
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p. 921 - 931
(2007/10/02)
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- Fungicidal composition for seed dressing
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The present invention relates to a fungicidal composition intended for the protection of the multiplication products of cultivated plants, containing: (a) 2-(4-chlorobenzylidene)-5,5-dimethyl-1-(1H-1,2,4-triazol-1-ylmethyl)-1-cyclopentanol; (b) one or more fungicides suitable for the protection of the said multiplication products, optionally one or more insecticides, (c), an agriculturally acceptable inert vehicle and an agriculturally acceptable surfactant. The invention also relates to a method for protecting the multiplication products of plants against fungal diseases using these compositions.
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- Studies on the Preparation of Dihydro-1,4-oxathiines. Computer-Assisted Evaluation of the Results of Retrosynthetic Analysis Verified by Synthetic Experiments and By-Product Analyses. Synthetic Pathways Involving α-Sulfenylated Ketones and 1,3-Oxathiolanes of α-Halo and α-Hydroxy K...
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The preparation of 2- and 2,3-substituted 5,6-dihydro-1,4-oxathiines has been studied by computer simulation and by experiment.Three major synthetic pathways, involving 2-(1-hydroxyalkyl)-1,3-oxathiolanes, 2-(1-haloalkyl)-1,3-oxathiolanes, 2-hydroxyethylthiomethyl ketones, methanesulfonates of 2-hydroxyethylthiomethyl ketones and 2-choroethylthiomethyl ketones as intermediates, were evaluated, by running the program CAMEO, and by experiment.The results of the two approaches were compared and the major by-products of the reactions were identified by GLC/MS.
- Nevalainen, Vesa,Pohjala, Esko,Maelkoenen, Pentti,Hukkanen, Heikki
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p. 591 - 602
(2007/10/02)
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- N-alkyl-2,6-dimethylmorpholinocarboxamide salts, compositions and their use as fungicides
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Novel N-alkyl-2,6-dimethylmorpholinocarboxamide salts of the general formula I, STR1 processes for their preparation, and their use as fungicides for controlling pathogenic fungi. The agents according to the invention additionally possess plant growth-regulating properties. The meanings of R1, R2, R3, R4 and X- are given in the description. (Formula I)
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- Studies on the Formation of Dihydro-1,4-oxathiines by Halogenation of 1,3-Oxathiolanes.
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Formation of 5,6-dihydro-1,4-oxathiines (1a-g) by halogenation of 1,3-oxathiolanes (4a-g) was investigated.Moderate yields of (1) were obtained in systems in which the newly formed double bond of the heterocyclic ring was stabilised by conjugation.In addition to the dihydro-1,4-oxathiines (1a-g), their halogenated derivatives and some fused and spiro 1,4-oxathianes were produced as by-products.By-products of reactions were analysed by gas chromatography and mass-spectrometry.
- Nevalainen, Vesa,Pohjala, Esko
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p. 1401 - 1421
(2007/10/02)
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- Synthesis of Dihydro-1,4-oxathiins by Action of Chlorine on 1,3-Oxathiolanes
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A new convenient synthesis of 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxylic acid derivatives 1 has been achieved by using the action of chlorine on 2-methyl-N-phenyl-1,3-oxathiolane-2-acetamide (4a) and 2-methyl-1,3-oxathiolane-2-acetic acid methyl ester (4b).From the initially formed chlorosulfonium salts 16 unobserved transient sulfenyl chlorides 5 were generated, followed by cyclization to probable oxonium ion 18 to produce dihydrooxathiins 1.In the chlorinolysis reactions of 4a and 4b minor byproducts were formed: respectively 2,3-dichloro-2-methyl-1,4-oxathiin-3-carboxanilide 12a and its methyl ester analogue 12b.While 12b was stable, 12a was unstable, transforming to the corresponding 2-chloromethyl compound 13.The mechanism of formation of 13 as well as relative stability of dichlorides 12a, 12b, and related compounds is also discussed.
- Lee, Wha Suk,Park, Oee Sook,Choi, Joong Kwon,Nam, Kee Dal
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p. 5374 - 5377
(2007/10/02)
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- Process for preparing 5,6-dihydro-2-methyl-1,4-oxathiin derivatives
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5,6-Dihydro-2-methyl-1,4-oxathiin derivatives are prepared by chlorinolysis of an appropriate 1,3-oxathiolane derivative to generate alkene-sulfenic acid, followed by cyclization and loss of hydrogen chloride to form said product.
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- Process for preparing 5,6-dihydro-2-methyl-1,4-oxathiin derivatives
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5,6-Dihydro-2-methyl-1,4-oxathiin derivatives are prepared by converting an appropriate 1,3-oxathiolane derivative to its sulfoxide and subjecting the sulfoxide to acid catalyzed rearrangement to form the desired product.
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