id	author	title	date	pages	extension	mime	words	sentence	flesch	summary	cache	txt
eurjchem-500	El-Shaaer, Hafez Mohamed	Cyclocondensation, antimicrobial activity and semi-empirical AM1-MO calculations of benzopyrone derivatives	2012	6	.pdf	application/pdf	3594	169	56	The calculated bond lengths of C=O groups (Å) on the basis of semi‐empirical AM1 method are linearly related to the measured IR C=O groups (cm‐1) for compounds (2‐12) and from the linear relation bond length (C=O) = 1.47‐0.001 C=O, r = 0.9140 except (7), where r is regression coefficient. The formation of compounds 2 and 6 proceeded via ,β‐ unsaturated ester derivatives (4), which can be cyclized under the effect of heat to give compound 5, further Claisen condensation on active methyl group of compound 5 followed by nucleophilic cyclization gave compounds (2, 6) (Scheme 3).	cache/eurjchem-500.pdf	txt/eurjchem-500.txt