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161 KiB

Open AccessArticle

Microwave Assisted Regioselective Bromomethoxylation of Alkenes Using Polymer Supported Bromine Resins

by Geetha Gopalakrishnan, Viswanathan Kasinath, N. D. Pradeep Singh, V. P. Santhana Krishnan, K. Anand Solomon and S. S. Rajan

Molecules 2002, 7(5), 412-419; https://doi.org/10.3390/70500412 - 31 May 2002

Cited by 10 | Viewed by 8774

Abstract

A facile regio- and chemoselective bromomethoxylation of alkenes under microwave irradiation conditions employing a new polymer supported brominechloride resin is reported. The resin is prepared from the commercially available chloride resin by a simple one step procedure. Full article

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197 KiB

Open AccessArticle

Regio- and Stereoselective [2+2] Photodimerization of 3-Substituted 2-Alkoxy-2-oxo-2H-1,2-benzoxaphosphorines

by Rositca D. Nikolova, G. N. Vayssilov, Nestor Rodios and Anka Bojilova

Molecules 2002, 7(5), 420-432; https://doi.org/10.3390/70500420 - 31 May 2002

Cited by 30 | Viewed by 8389

Abstract

Diethyl 1,2-benzoxaphosphorine-3-carboxylates 5 undergo a regio- and stereoselective [2+2] photodimerization reaction in methanol solution under the action of sunlight, giving in all cases the corresponding anti head-to-tail dimers 6 and 7. Concerning the stereogenic P atom, the photodimerization is also stereoselective, and the [...] Read more.

Diethyl 1,2-benzoxaphosphorine-3-carboxylates 5 undergo a regio- and stereoselective [2+2] photodimerization reaction in methanol solution under the action of sunlight, giving in all cases the corresponding anti head-to-tail dimers 6 and 7. Concerning the stereogenic P atom, the photodimerization is also stereoselective, and the centrosymmetric stereoisomer 6 predominates over the non symmetric P-epimer 7. Full article

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27 KiB

Open AccessArticle

A New Palladium-Catalyzed Phenyl-Alkene Bond Formation

by Brad Schmor and René Roy

Molecules 2002, 7(5), 433-436; https://doi.org/10.3390/70500433 - 31 May 2002

Cited by 4 | Viewed by 6872

Abstract

A new method of palladium-catalyzed phenyl-alkene bond formation is reported. This reaction involves transfer of all three phenyl groups from triphenylantimony onto alkenes containing allylic protons. Full article

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345 KiB

Open AccessArticle

Synthesis, Crystal Structure, and Conformation of Methyl 5-Oacetyl-5-cyano-6-deoxy-2,3-O-isopropylidene-β-L-gulofuranoside

by Júlia Mičová, Bohumil Steiner, Miroslav Koóš, Ján Gajdoš, Vratislav Langer and Dalma Gyepesová

Molecules 2002, 7(5), 437-446; https://doi.org/10.3390/70500437 - 31 May 2002

Cited by 2 | Viewed by 7843

Abstract

Methyl 5-O-acetyl-5-cyano-6-deoxy-2,3-O-isopropylidene-β-L-gulofuranoside was prepared in high yield from methyl 6-deoxy-2,3-O-isopropylidene-α-D-lyxopentodialdo-1,4-furanoside. The configuration at the C5 atom was unambiguosly established by single crystal X-ray analysis of the corresponding 5-O-acetyl derivative. The conformation of the furanose and 1,3-dioxolane rings is also discussed. Full article

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77 KiB

Open AccessArticle

Synthesis of “Acetylene-Expanded” Tridentate Ligands

by Brian T. Holmes, William T. Pennington and T. W. Hanks

Molecules 2002, 7(5), 447-455; https://doi.org/10.3390/70500447 - 31 May 2002

Cited by 11 | Viewed by 9115

Abstract

Synthetic routes to four new tridentate ligands with large cavities have been developed. Each ligand features two halides at the termini of the molecules that could be used for further elaboration of the system. Such compounds are ideal for encapsulating organoiodide guests using [...] Read more.

Synthetic routes to four new tridentate ligands with large cavities have been developed. Each ligand features two halides at the termini of the molecules that could be used for further elaboration of the system. Such compounds are ideal for encapsulating organoiodide guests using charge-transfer interactions. Full article

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45 KiB

Open AccessArticle

Niobium Pentachloride Activation of Enone Derivatives: Diels-Alder and Conjugate Addition Products

by Mauricio Gomes Constantino, Valdemar Lacerda Júnior and Gil Valdo José Da Silva

Molecules 2002, 7(5), 456-464; https://doi.org/10.3390/70500456 - 31 May 2002

Cited by 18 | Viewed by 11520

Abstract

Niobium pentachloride has proven to be a powerful activating agent for Diels-Alder or conjugate addition reactions of cycloenones. The Diels-Alder product was obtained only with an unsubstituted enone (cyclohexenone) and the highly reactive diene cyclopentadiene; substituents in the b-position of enones seem to [...] Read more.

Niobium pentachloride has proven to be a powerful activating agent for Diels-Alder or conjugate addition reactions of cycloenones. The Diels-Alder product was obtained only with an unsubstituted enone (cyclohexenone) and the highly reactive diene cyclopentadiene; substituents in the b-position of enones seem to prevent Diels-Alder reaction: oxygenated substituents favor the formation of vinyl chlorides (ethyl ether or dichloromethane as solvents) or enol ethers (ethyl acetate as solvent), while a methyl substituent prevents any kind of transformation with NbCl₅. Less reactive dienes, furan and 2-methylfuran gave the conjugate addition products of the furan ring to the enone system. Full article

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66 KiB

Open AccessArticle

Microwave Assisted Facile Cleavage of 2,4-Dinitrophenylhydrazones to the Corresponding Carbonyl Compounds with N,N′-Dibromo-N,N′-1,2-ethanediylbis(p-toluenesulphonamide)

by Ardeshir Khazaei and Ramin Ghorbani Vaghei

Molecules 2002, 7(5), 465-468; https://doi.org/10.3390/70500465 - 31 May 2002

Cited by 6 | Viewed by 6896

Abstract

Deprotections of 2,4-dinitrophenylhydrazones to their corresponding carbonyl compounds have been carried out in good yields by using N,N′-dibromo-N,N′-1,2-ethanediylbis(p-toluenesulphonamide) (BNBTS, 2) under microwave irradiation. Full article

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Molecules, Volume 7, Issue 5 (May 2002) – 7 articles , Pages 412-468

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