Letters in Organic Chemistry - Volume 3, Issue 9, 2006

N-Lithiated azomethine ylides generated from N-arylidene-α-amino esters react on their C&ggr:-atom with a 7-oxabicyclo[2.2.1]heptadiene derived diester. This regio- and stereoselective Michael addition yields β-amino diesters after acidic work-up. Retro-Diels-Alder reaction from these amines or related amides allows the preparation of (aminomethyl)maleate derivatives.

A one-step methodology for the synthesis of carbasugar, involving tandem Wittig-Horner, Mitsunobu, and Michael mechanisms, is disclosed. The strategy involves CMMP and allows a quick access to a new variety of carbasugar derivatives.

Alkyl and aryl 2,3-unsaturated glycosides have been prepared by the reaction of alcohols or thiols with 3,4,6-tri-O-acetyl-D-glucal in acetonitrile at room temperature in the presence of a catalytic amount of magnesium perchlorate. Similarly, glycals have shown to react smoothly with silyl nucleophiles such as trimethylsilyl azide, allyltrimethylsilane, trimethylsilyl cyanide and in the presence of a catalytic amount of magnesi Read More

Solis alkaline metal hydroxides displayed activity in alcohol oxidation in non-polar medium. Both organic molecules and molecular oxygen were employed as oxidants. The activity was in order KOH>NaOH≫ LiOH.

Mannose is selectively converted into mannose-1-phosphate (Man-1-P, 1) without protection of the other hydroxyl groups by phosphorylation of the anomeric hydroxyl in dry tetrahydrofuran (THF) containing phosphoric acid. Compound 1 is activated with GTP and recombinant GDP-mannose pyrophosphorylase (GDPMan PP) to give GDP-Man 2.

Sesquiterpene adducts have been obtained by the reactions of 3-methyl-3-cyanocyclopropene with (-) -pinene and (-)carvone, proceeding by Alder-ene pathway. In the reaction with -pinene only one diastereoisomer (∼95 %) was formed, while in the case of carvone a mixture of two diastereoisomers almost in equal quantities (55:45) was obtained.

A number of AB2-functionalized triphenylene derivatives have been synthesized through a convenient approach. Such compounds are potential building block molecules for the synthesis of triphenylene-based dendrimers.

Investigations on the lipase-catalyzed polymerization of glycidol that are known from literature are presented. We found that the active site of enzymes is possibly not the crucial unit for the catalytic activity. The functional groups at the side chains of different amino acids may be responsible for the catalytic activity.

A couple of TEMPO-substituted anthraquinone isomers showed marked difference regarding solvating properties and the resulting magnetic behavior: without obstruction an isomer includes solvent molecules as benzene or acetonitrile to form crystals exhibiting different intermolecular magnetic interactions, while another isomer gives solvent-free crystals showing singlet-triplet behavior.

N-4-R-Benzyl-N-nitrosoamides were decomposed at various temperatures in selected solvents. From their decomposition rates, contributions from ΔH* and ΔS* evidently depend upon intramolecular and solvent effects consistent with an early metastable oxadiazetyl-type entity in the first and rate-determining step of nitrosoamide thermolyses as opposed to a first, slowest step to a trans-diazoester.

An efficient and simple synthesis of biologically important C-2 α-furyl substituted quinolines and isoindolo[2,1-a]quinolines using the same 2-(α-furyl)-4-(2-oxopyrrolidinyl-1)-1,2,3,4-tetrahydroquinolines prepared by imino Diels-Alder reaction was reported.

The Diels-Alder reactions of the ortho-quinodimethane (o-QDM) thermally generated from 2,4- diphenylciclobutapyrimidine with the dienophiles diethyl maleate, diethyl fumarate and dimethyl acetylenedicarboxylate have been investigated. The reaction afforded 5,6,7,8-tetrahydroquinazoline and quinazoline derivatives. While diethyl maleate formed a mixture of cis- and trans-adducts, diethyl fumarate gave only the trans-add Read More

Synthesis of biologically important thieno[2,3-d]pyrimidine derivatives 6a-f in 65-78% yields have been reported. The conditions applied here are based on the less studied tandem rearrangement protocol. The precursor sulfides in 73-85% were prepared from N,N-dimethyl-6-cholouracil and 1-aryloxy-4-chlorobut-2-yne by phase transfer catalyzed reaction condition.

We have synthesized a library of 12 bis-imidazolyl indoles in high yields (84-95%) using microwave irradiation.

Considering relatively undeveloped chemistry of ring-forming condensations of 1H-pyrazole-5- amines with cyclic versions of β-oxoesters, a novel tricyclic piperidine ring-fused pyrazolo[1,5-a]pyrimidin- 7(4H)-one scaffold was designed. The developed synthetic scheme features regioselective construction of the core tricyclic molecular scaffold and a remarkable case of convenient and high-yielding p-methoxybenzyl group rem Read More

Diphenyl[2-(phenylsulfinyl)ethyl]phosphine oxide readily accessible from diphenylphosphine oxide and phenyl vinyl sulfoxide reacts with sodium amide to form diphenyl(vinyl)phosphine oxide in good yield. The reaction involves generation of phosphoryl-stabilized carbanions which further eliminate benzene sulfenate anions. The preferred formation of phosphoryl-stabilized carbanions in the vicinal O=SCH2CH2P=O moiety i Read More