The lithiation of 2-(2,2-dimethyl-1,3-dioxolan-4-yl)ethyl diisopropylcarbamate (1) is achieved freely by sec-butyllithium in diethylether with high lk-diastereoselectivity: the bicyclic chelate complexes 3a and 3b are reacted with electrophiles to form optically active precursors 4a and 4b with >95% diastereoselectivity. In addition, tertiary diamines can undergo an external complexation in contest with the internal oxygen ligand, leading to improved stereoselectivities.

The aromaticities of azines relative to benzene have been estimated by fusion with 15,16-dimethyldihydropyrene. Chemicalshift data for the azine-fused dihydropyrenes (calculated at GIAO HF/6-31G*//B3LYP/6-31 + G*) were used to estimate thereduction in the dihydropyrene nucleus aromaticity. Choice of the saturated reference model was quite crucial in reliable estimation of aromaticity. Reference models with partial unsaturation at azine (21,23,25–32) gave better estimate of aroma-ticity than the parent dimethyldihydropyrene.

Based on the fact that the thymidine phosphorylase inhibitors are considered potential anti-tumor agents, a range of novel oxadiazole derivatives 3a–3u was designed and synthesized by a simple and facile synthetic route. The biological assay revealed that majority of compounds displayed modest inhibitory activity against thymidine phosphorylase at low micromolar concentrations (IC50 173.23 ± 3.04 to 14.40 ± 2.45 μM).

Objectives:- The purpose of this study was to assess the blood levels of zinc (Zn) and iron (Fe) in of children. Subjects and Methods:- This descriptive was carried out in the Department of Chemistry, Bahauddin Zakariya University, Multan, PMRC Research Center, Nishtar Medical College, Multan, Department of Paediatric Medicine, Nishtar Medical College, Multan, Pakistan. 2004-2005.One hundred children (boys & girls) aged 1-10 years belonging to rural and urban areas attending the out patient department for minor illnesses at Nishtar Hospital, Multan were included in this study.

2,3,4,5,6-Pentasubstituted tetrahydropyrans have been prepared in good yield (42–57%) with excellent dr (>95:5) and er (>95:5) using a one-pot lithiation–borylation, allylation and Prins cyclisation reaction.

Abstract: The reactions of Hoppe’s lithiated carbamates with vinylboranes and boronic esters give allylic boranes/boronic esters, and subsequent addition of aldehydes provides a new route to enantioenriched homoallylic alcohols with high enantiomeric ratios and diastereomeric ratios. Specifically, reactions of sparteine-complexed lithiated carbamates with trans-alkenyl-9-BBN derivatives followed by addition of aldehydes gave (Z)-anti-homoallylic alcohols in greater than 95:5 er and 99:1 dr.

We have developed a process for the homologation of boranes and boronic esters using Hoppe-type lithiated carbamates which shows very broad substratescope. The Hoppe-type lithiated carbamates are effectively chiral carbenoids and are derived from the simplest of reagents: primary alcohols. The power of the methodology lies in its iterative use.