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Abstract: A new synthesis of 2,3-dialkyl-4-carbomethoxyisoquinolin-1(2H)-ones and 6,7-dialkyl-8-carbomethoxy-1,6-naphthyridin-5(6H)-ones is reported. The process involves treatment of a β-enaminoester with 2-fluoro-5-nitrobenzoyl chloride, 2-fluorobenzoyl chloride or 2-chloronicotinoyl chloride followed by heating in the presence of base. The conversion, which proceeds by an N-acylation-SNAr reaction sequence, affords 50–86% yields when R1 is n-alkyl but ≤30% yields when R1 is α-branched. [Copyright &y& Elsevier]

Abstract: Nano-MnO2 has been developed as an efficient and mild reagent for the high-yield oxidation of arylmethylene compounds to the corresponding aldehydes and ketones as well as benzylic ethers to esters. The reagent is conveniently prepared and shows reactivity superior to synthetic (Attenburrow) MnO2 and commercial MnO2 under both microwave and conventional conditions. Typical reactions are performed using 25wt% of nano-MnO2 relative to the substrate, and the reagent can be recycled up to six times without significant loss of activity. The observed conversions correlate well with surface-water content in the different MnO2 samples, as determined by thermogravimetric analysis. [Copyright &y& Elsevier]

Abstract: A series of substituted 2,4-diaminopyrimidines 1 has been prepared and evaluated for activity against Bacillus anthracis using previously reported (±)-3-{5-[(2,4-diamino-5-pyrimidinyl)methyl]-2,3-dimethoxyphenyl}-1-(1-propyl-2(1H)-phthalazinyl)-2-propen-1-one (1a), with a minimum inhibitory concentration (MIC) value of 1–3 μg/mL, as the standard. In the current work, the corresponding isobutenyl (1e) and phenyl (1h) derivatives displayed the most significant activity in terms of the lowest MICs with values of 0.5 μg/mL and 0.375–1.5 μg/mL, respectively. It is likely that the S isomers of 1 will bind the substrate-binding pocket of dihydrofolate reductase (DHFR) as in B. anthracis was found for (S)-1a. The final step in the convergent synthesis of target systems 1 from (±)-1-(1-substituted-2(1H)-phthalazinyl)-2-propen-1-ones 6 with 2,4-diamino-5-(5-iodo-3,4-dimethoxybenzyl)pyrimidine (13) was accomplished via a novel Heck coupling reaction under sealed-tube conditions. [Copyright &y& Elsevier]

An efficient and inexpensive approach to the synthesis of 2-substituted and 2,5-disubstituted 1,3,4-oxadiazoles from arylhydrazides and orthoesters is reported using catalytic NH 4 Cl. The conditions are mild, and thus, compatible with a variety of functional groups. The optimized reaction is performed using 30 mol % of NH 4 Cl in 100% EtOH and is generally complete within 1 h for non-aromatic orthoesters and 2–10 h for aromatic orthoesters. The reaction permits both electron-releasing and electron-withdrawing groups on the arylhydrazide substrate. Most products are formed in high yields and require only minimal purification. Compared with earlier reports, the current reactions proceed in shorter time and require less of the orthoester. [ABSTRACT FROM AUTHOR]

Review: 134 refs. [ABSTRACT FROM AUTHOR]

A tandem Michael--SNAr annulation reaction has been developed for the synthesis of 1-alkyl and (±)-1,2-dialkyl-2,3-dihydro-1,8-naphthyridin-4(1H)-ones. Treatment of 1-(2-chloropyridin-3-yl)prop-2-en-1-one (R = H) or (E or Z)-1-(2-chloropyridin-3-yl)but-2-en-1-one (R = CH3) with R'NH2 in DMF at 50 °C for 24 h provides 2,3-dihydro-1,8-naphthyridin-4(1H)-ones in 65-85% yields. Mechanistic studies suggest that the reaction sequence is initiated by Michael addition to the side chain enone. [ABSTRACT FROM AUTHOR]

The new approach for the synthesis of the title compounds requires substrates which can be conveniently prepared in two steps from commercial 2-chloro-3-pyridinecarboxaldehyde. [ABSTRACT FROM AUTHOR]