Pyrido- and pyrrolo[2,3-d]oxazoles can be conveniently prepared in high yield from the Ritter reaction of nitriles and in situ generated chiral cyclic N-acyliminium ions. cis-4-Hydroxy-5-acylaminopyrrolidines and cis-5-hydroxy-6-acylaminopiperidines can be readily obtained by acid hydrolysis of these bicyclic heterocyclic compounds, respectively.

The intramolecular Pd(II)-catalysed carbonylation of aminoalkenitol was used as a key step in the short racemic syntheses of the ladybird beetle alkaloids calvine and epicalvine. The title compounds have been prepared in 26% overall yield over four steps starting from hexanal and pentenyl bromide. 2007 Elsevier Ltd. All rights reserved. (+)-Calvine 1 and (+)-2-epicalvine 2 are bicyclic piperidi...

Z. Naturforsch. 61b, 431 – 436 (2006); received January 17, 2006 The 3,4-substituted 2-oxo-piperazines 5 – 9 are obtained by [3+2] cycloaddition from nitrone 1 and a variety of alkenes. Subsequent functionalization of the bicyclic adducts involves reductive N-O bond cleavage. A route towards libraries of immobilized 1,3-aminoalcohols with a 3,4-substituted 2-oxo-piperazine scaffold is briefly d...

Ga-modified H-Beta (Ga/HBEA) zeolites were evaluated and compared to other Ga-containing catalysts supported on SiO2 and ZSM-5 (MFI) for the hydrodeoxygenation of m-cresol, a model compound representative of lignin-derived phenolics. The products include toluene, benzene, xylene, light hydrocarbons, as well as phenol and other oxygenated compounds. The appearance of bicyclic compounds suggests ...

The chiral bicyclic lactam (2) derived from levulinic acid and (S)-valinol is sequentially alkylated and then cleaved to 2,2-dialkyl levulinaldehyde (5) which is cyclized to the title products (2) in > 99% ee.

5,6,7,8-Tetrahydroquinolines and 5,6,7,8-tetrahydronaphthyridines with appended trifluoromethyl groups are valuable chemotypes in medicinal chemistry due to the presence of a partially-saturated bicyclic ring and metabolically-stable CF(3) group. (1)H NMR studies were used to optimize the preparation of such compounds, using a three-step/one-pot procedure, to provide novel 2,6-disubstitued deri...

Abstract Pistacia lentiscus L. is an evergreen shrub belonging to the Anacardiaceae family, cultivated exclusively in southern area of Chios Island. Mastic gum as a unique natural resin tree has been used extensively functional foods and traditional medicine. The biological properties resins may be influenced by different chemical constituents. Herein present work aimed further explore diverse ...

The first total synthesis of (-)-16-episilicine has been completed from a phenylglycinol-derived bicyclic lactam, the key steps being stereoselective conjugate addition and alkylation reactions, and a ring-closing metathesis.

Reaction of the amino acid D-phenylalanine ethyl ester (4) with cinnamaldehyde gave chiral Schiff base 5, which underwent an asymmetric Staudinger [2+2] cycloaddition reaction with phthalimidoacetyl chloride to give the monocyclic beta-lactam 6 as a single stereoisomer. Ozonolysis of 6 followed by reduction with lithium aluminum tri(tert-butoxy) hydride afforded the hydroxymethyl beta-lactam 8....