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Prakas R Maulik - One of the best experts on this subject based on the ideXlab platform.
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stereoselective alkenylation of a 1 3 disubstituted pyrazol 5 one through ring transformation of 2h pyran 2 ones
Tetrahedron Letters, 2005Co-Authors: Rishi Kumar, Ashoke Sharon, Prakas R MaulikAbstract:Abstract A one-pot stereoselective alkenylation of 1-(3-chlorophenyl)-3-methyl-1,4-dihydro-5-pyrazolone 2 by 2 H -pyran-2-ones 1 to give ( E , E )-5-aryl-5-[1-(3-chlorophenyl)-3-methyl-5-oxo-1,5-dihydropyrazol-4- ylidene]-3-methylsulfanyl-pent-3-en-carbonitrile/methyl carboxylate 3 has been delineated through ring transformation in moderate yields.
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one pot synthesis of cyclopentadienones through ring contraction of 2h pyran 2 ones
Tetrahedron Letters, 2004Co-Authors: Ashoke Sharon, Prakas R MaulikAbstract:A one-pot synthesis of 2,3,5-trisubstituted cyclopentadienones has been delineated through ring contraction of suitably functionalized 2H-Pyran-2-Ones using either cyanoacetamide or methyl cyanoacetate.
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carbanion induced synthesis of annulated unsymmetrical biaryls through ring transformation of 2h pyran 2 one
Journal of The Chemical Society-perkin Transactions 1, 2002Co-Authors: Nidhi Agarwal, Ashoke Sharon, Abhishek S Saxena, Prakas R MaulikAbstract:An innovative and convenient one-pot synthesis of unsymmetrical macrocyclic biaryls (3, 5 and 8), dibenzo[a,c]cycloheptenes (10), 3,4-dihydro-2(1H)-naphthones (15), tetrahydroisoquinolines (18), dihydro-1H-isothiochromenes (20), benzo[c]thiochromenes (22) and 2,3-dihydro-1-benzothiophenes (24) is described. These compounds are obtained through base-catalyzed ring transformation reactions of suitably functionalized 2H-Pyran-2-Ones (1,6) by a carbanion, generated from cycloalkanone (2,4,7), benzosuberone (9), cyclohexanedione monoketal (12), 4-piperidone (17), tetrahydrothiopyran-4-one (19), thiochroman-4-one (21) or tetrahydrothiophene-3-one (23).
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an expeditious synthesis of imidazo 1 2 a pyridines through nucleophile induced ring transformation reactions of 6 aryl 4 methylsulfanyl 2h pyran 2 one 3 carbonitriles
Tetrahedron Letters, 2002Co-Authors: Nidhi Agarwal, Ashoke Sharon, Prakas R MaulikAbstract:An efficient and convenient synthesis of 2-(5-aryl-8-nitro-2,3-dihydroimidazo[1,2-a]pyridin-7(1H)-ylidene)acetonitriles (3) and 6-aryl-4-{2-[(E)-nitromethylidene]-1-imidazolidinyl}-2-oxo-2H-pyran-3-carbonitriles (4) through nucleophile induced ring transformation of suitably functionalized 2H-Pyran-2-One (1) from imidazoliden-2-ylidene nitromethane is delineated.
Nidhi Agarwal - One of the best experts on this subject based on the ideXlab platform.
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carbanion induced synthesis of dibenzo a c cycloheptenes through ring transformation reactions of 2h pyran 2 one
Tetrahedron Letters, 2002Co-Authors: Nidhi AgarwalAbstract:Abstract An efficient and convenient one-pot synthesis of 4-aryl-2-methylsulfanyl-6,7-dihydro-5 H -dibenzo[ a , c ]cycloheptene-1-carboxylate 3a – n has been delineated and illustrated through carbanion induced ring transformation of 6-aryl-3-carbomethoxy-4-methylsulfanyl-2 H -pyran-2-ones 1 with benzosuberone 2 .
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carbanion induced synthesis of annulated unsymmetrical biaryls through ring transformation of 2h pyran 2 one
Journal of The Chemical Society-perkin Transactions 1, 2002Co-Authors: Nidhi Agarwal, Ashoke Sharon, Abhishek S Saxena, Prakas R MaulikAbstract:An innovative and convenient one-pot synthesis of unsymmetrical macrocyclic biaryls (3, 5 and 8), dibenzo[a,c]cycloheptenes (10), 3,4-dihydro-2(1H)-naphthones (15), tetrahydroisoquinolines (18), dihydro-1H-isothiochromenes (20), benzo[c]thiochromenes (22) and 2,3-dihydro-1-benzothiophenes (24) is described. These compounds are obtained through base-catalyzed ring transformation reactions of suitably functionalized 2H-Pyran-2-Ones (1,6) by a carbanion, generated from cycloalkanone (2,4,7), benzosuberone (9), cyclohexanedione monoketal (12), 4-piperidone (17), tetrahydrothiopyran-4-one (19), thiochroman-4-one (21) or tetrahydrothiophene-3-one (23).
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an expeditious synthesis of imidazo 1 2 a pyridines through nucleophile induced ring transformation reactions of 6 aryl 4 methylsulfanyl 2h pyran 2 one 3 carbonitriles
Tetrahedron Letters, 2002Co-Authors: Nidhi Agarwal, Ashoke Sharon, Prakas R MaulikAbstract:An efficient and convenient synthesis of 2-(5-aryl-8-nitro-2,3-dihydroimidazo[1,2-a]pyridin-7(1H)-ylidene)acetonitriles (3) and 6-aryl-4-{2-[(E)-nitromethylidene]-1-imidazolidinyl}-2-oxo-2H-pyran-3-carbonitriles (4) through nucleophile induced ring transformation of suitably functionalized 2H-Pyran-2-One (1) from imidazoliden-2-ylidene nitromethane is delineated.
Ashoke Sharon - One of the best experts on this subject based on the ideXlab platform.
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stereoselective alkenylation of a 1 3 disubstituted pyrazol 5 one through ring transformation of 2h pyran 2 ones
Tetrahedron Letters, 2005Co-Authors: Rishi Kumar, Ashoke Sharon, Prakas R MaulikAbstract:Abstract A one-pot stereoselective alkenylation of 1-(3-chlorophenyl)-3-methyl-1,4-dihydro-5-pyrazolone 2 by 2 H -pyran-2-ones 1 to give ( E , E )-5-aryl-5-[1-(3-chlorophenyl)-3-methyl-5-oxo-1,5-dihydropyrazol-4- ylidene]-3-methylsulfanyl-pent-3-en-carbonitrile/methyl carboxylate 3 has been delineated through ring transformation in moderate yields.
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one pot synthesis of cyclopentadienones through ring contraction of 2h pyran 2 ones
Tetrahedron Letters, 2004Co-Authors: Ashoke Sharon, Prakas R MaulikAbstract:A one-pot synthesis of 2,3,5-trisubstituted cyclopentadienones has been delineated through ring contraction of suitably functionalized 2H-Pyran-2-Ones using either cyanoacetamide or methyl cyanoacetate.
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carbanion induced synthesis of annulated unsymmetrical biaryls through ring transformation of 2h pyran 2 one
Journal of The Chemical Society-perkin Transactions 1, 2002Co-Authors: Nidhi Agarwal, Ashoke Sharon, Abhishek S Saxena, Prakas R MaulikAbstract:An innovative and convenient one-pot synthesis of unsymmetrical macrocyclic biaryls (3, 5 and 8), dibenzo[a,c]cycloheptenes (10), 3,4-dihydro-2(1H)-naphthones (15), tetrahydroisoquinolines (18), dihydro-1H-isothiochromenes (20), benzo[c]thiochromenes (22) and 2,3-dihydro-1-benzothiophenes (24) is described. These compounds are obtained through base-catalyzed ring transformation reactions of suitably functionalized 2H-Pyran-2-Ones (1,6) by a carbanion, generated from cycloalkanone (2,4,7), benzosuberone (9), cyclohexanedione monoketal (12), 4-piperidone (17), tetrahydrothiopyran-4-one (19), thiochroman-4-one (21) or tetrahydrothiophene-3-one (23).
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an expeditious synthesis of imidazo 1 2 a pyridines through nucleophile induced ring transformation reactions of 6 aryl 4 methylsulfanyl 2h pyran 2 one 3 carbonitriles
Tetrahedron Letters, 2002Co-Authors: Nidhi Agarwal, Ashoke Sharon, Prakas R MaulikAbstract:An efficient and convenient synthesis of 2-(5-aryl-8-nitro-2,3-dihydroimidazo[1,2-a]pyridin-7(1H)-ylidene)acetonitriles (3) and 6-aryl-4-{2-[(E)-nitromethylidene]-1-imidazolidinyl}-2-oxo-2H-pyran-3-carbonitriles (4) through nucleophile induced ring transformation of suitably functionalized 2H-Pyran-2-One (1) from imidazoliden-2-ylidene nitromethane is delineated.
Jeroen S Dickschat - One of the best experts on this subject based on the ideXlab platform.
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2h pyran 2 ones from trichoderma viride and trichoderma asperellum
European Journal of Organic Chemistry, 2013Co-Authors: Susanne Wickel, Christian A Citron, Jeroen S DickschatAbstract:Volatiles emitted by the soil fungi Trichoderma viride 272 and Trichoderma asperellum 328 were collected by using the closed loop stripping analysis (CLSA) headspace technique, and the obtained extracts were analysed by GC/MS. Several alkyl- and alkenyl-2H-Pyran-2-Ones, including known compounds 6-pentyl-2H-Pyran-2-One and (E)-6-(pent-1-en-1-yl)-2H-Pyran-2-One, and the new derivatives (E)-6-(pent-2-en-1-yl)-2H-Pyran-2-One, 6-propyl-2H-Pyran-2-One, and 6-heptyl-2H-Pyran-2-One were found. The alkenyl derivative (E)-6-(hept-1-en-1-yl)-2H-Pyran-2-One, previously tentatively identified from a marine Botrytis by MS analysis, was also detected. All alkenyl pyrones were synthesised by using a reported Stille coupling followed by lactonisation, whereas the alkylated pyrones were obtained through a reported synthetic approach by radical bromination of 5-alkylpent-2-en-5-olides and dehydrobromination. Because the yields in both cases were not satisfactory and fell a long way short of the yields reported for similar compounds, all compounds were synthesised again using a gold-catalysed coupling of terminal alkynes with propiolic acid recently developed by Schreiber and co-workers, giving high yields in all cases. A comparison of the synthetic methods is given.
Susanne Wickel - One of the best experts on this subject based on the ideXlab platform.
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2h pyran 2 ones from trichoderma viride and trichoderma asperellum
European Journal of Organic Chemistry, 2013Co-Authors: Susanne Wickel, Christian A Citron, Jeroen S DickschatAbstract:Volatiles emitted by the soil fungi Trichoderma viride 272 and Trichoderma asperellum 328 were collected by using the closed loop stripping analysis (CLSA) headspace technique, and the obtained extracts were analysed by GC/MS. Several alkyl- and alkenyl-2H-Pyran-2-Ones, including known compounds 6-pentyl-2H-Pyran-2-One and (E)-6-(pent-1-en-1-yl)-2H-Pyran-2-One, and the new derivatives (E)-6-(pent-2-en-1-yl)-2H-Pyran-2-One, 6-propyl-2H-Pyran-2-One, and 6-heptyl-2H-Pyran-2-One were found. The alkenyl derivative (E)-6-(hept-1-en-1-yl)-2H-Pyran-2-One, previously tentatively identified from a marine Botrytis by MS analysis, was also detected. All alkenyl pyrones were synthesised by using a reported Stille coupling followed by lactonisation, whereas the alkylated pyrones were obtained through a reported synthetic approach by radical bromination of 5-alkylpent-2-en-5-olides and dehydrobromination. Because the yields in both cases were not satisfactory and fell a long way short of the yields reported for similar compounds, all compounds were synthesised again using a gold-catalysed coupling of terminal alkynes with propiolic acid recently developed by Schreiber and co-workers, giving high yields in all cases. A comparison of the synthetic methods is given.