Letters in Organic Chemistry - Volume 3, Issue 10, 2006

In this study we report on the preparation of 3'-oxolutein (1) by MnO2- and NiO2-oxidation of lutein (2) and the complete structure elucidation of this carotenoid by spectroscopic (UV/VIS, IR, 1H-NMR, 13C-NMR, CD, MS) methods and chemical reaction (NaBH4 reduction). The complete assignment of the 13CNMR spectrum of this carotenoid will be presented for the first time. A new carotenoid with alternative structure ( Read More

The anion binding properties of 2,2'-dihydroxyl-1,1'-binaphtalene (BINOL) derivatives were studied by 1H NMR spectroscopy. BINOL derivatives formed the complex with anions through hydrogen bonding using hydroxyl groups and showed a binding preference to dihydrogen phosphate (H2PO4 -) and acetate (CH3CO2-) in comparison with other anions (Cl-, Br-, I-, NO3-, and HSO4-) tested.

A facile synthesis of the title compound has been developed starting from the crotylated product of (R)-cyclohexylideneglyceraldehyde (2). The key features of the synthesis were stereochemical control of the crotylation by alteration of reaction conditions, operational simplicity and the use of inexpensive compounds/reagents.

Activated 1,2-glycerol carbonate has been subjected to nucleophilic substitution with oxygen-, nitrogen- and sulfur nucleophiles. Selective reactions with thiol derivatives have been especially investigated for the preparation of mono- and dithiofunctionalized 3-carbon synthons.

We describe an efficient and practical preparation of α-hydroxyl cyclobutanones from 1,2- Bis(trimethylsiloxy)cyclobutene (BTCB) with aromatic aldehydes, α,β-unsaturated aldehydes and their parent acetals catalyzed by 1-5 mol% of MgI2 etherate (MgI2•(OEt2)n) in dichloromethane under mild reaction conditions in good yields.

Picket porphyrins delivering oxygen donor atoms borne by aromatic cycles around the sphere of coordination of bismuth cation have been studied for their ability to complex bismuth in a period of time not exceeding an hour. For this investigation, various structural features were considered: steric strength and length of the link between the aromatic cycle and the macrocyle core, nature and location of the oxygen atom(s) on Read More

The reaction of 4-methyl-2-(methoxyphenyl)nicotinic acid with Eaton's reagent (P2O5 - CH3SO3H) affords pyrido[3,2-c]coumarin derivatives or 1-methyl-4-azafluoren-9-ones depending on the position of the methoxy group on the benzene ring.

Enzymatic acetylation of several varieties of N-Cbz-2-alkyl-2-amino-1,3-propanediols 3a-d with immobilized lipoprotein lipase from Pseudomonas sp. afforded N-Cbz-3-acetoxy-2-alkyl-2-amino-1-propanols 4a-d in up to 98% ee. A facile synthesis of (R)- and (S)-a-benzylserines [(R)- and (S)-8a] was achieved by enantiodivergent conversion of chiral N-Cbz-3-acetoxy-2-amino-2-benzyl-1-propanol (R)-4a.

Electrophilic substitution reactions of indoles with various aldehydes and ketones using catalytic amounts of BiOClO4•xH2O and Bi(OTf)3 in acetonitrile at room temperature and under ultrasound irradiation afforded the corresponding bis(indolyl)methanes in good to excellent yields. Selective condensation of indoles with aldehydes in the presence of ketones can be performed with these catalysts.

An innovative procedure aimed to the production of orthogonally protected amino-derivatives of high-molecular weight poly(ethylene glycol) (PEG) modified with linkers bearing differently reactive terminal amino groups is reported. This polymeric derivative represents a convenient, new soluble support particularly suitable as a drug delivery system of mixed molecules.

Chiral C3-symmetric tripodal tris(β-hydroxy amide) ligands have been conveniently synthesized via the reaction of 1,3,5-benzenetricarboxylic chloride and chiral amino alcohols, and the corresponding tris(amino alcohol) ligands were obtained via the borane reduction of amides. The asymmetric diethylzinc addition to various aldehydes catalyzed by these chiral ligand-Ti (IV) complexes gave modest enantioselectivities.

A new calix[4]arene derivative in 1,3-alt conformation containing thiourea moieties is synthesized and examined for its anion binding ability by UV-Vis and 1H NMR studies. The results show that the receptor has selective colorimetric sensing of cyanide over all other anions like fluoride, chloride, bromide, iodide, nitrate, hydrogen sulphate, dihydrogenphosphate and acetate.

Michael addition of thiophenol to chalcone was studied in different solvents. It was proved that reaction proceed very well in ionic liquids and chosen conventional solvents without any catalyst. It was also proved that reaction proceed well also with other thiols and other enones. Addition of selenophenol to chalcone in ethanol was also successful.