The structure of synthesized 2,5-dimethyl-3,4-dihydro-2H-pyran-2-carboxylic acid was investigated by the single crystal X-ray diffraction analysis method. It was established that the molecule of the acid exists in the form of the endo isomer while the single crystal exists as a racemate of the two enantiomeric endo stereomers. Quantum-chemical calculations of a model of the macrocell of the acid by means of the semiempirical MOPAC2009 program agree well with the X-ray diffraction data.

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Pyran derivatives R 0340Synthesis and Biological Activity of α-Alkylacrolein Dimers and Their Derivatives. -Alkylacrolein dimers (II), synthesized using Diels-Alder reaction, undergo Cannizzaro reaction to give the corresponding alcohols (III) and carboxylic acid salts (IV). Compounds (II) and (III) show bactericidal, fungicidal and bacteriostatic activities. -(KARPIAK*, N. M.; MARSHALOK, H. A.; FEDEVICH, M. D.; AVDOSIEVA, I. K.; KOVALSKYI, Y. P.; Chem. Heterocycl. Compd. (N. Y.) 44 (2008) 11, 1334-1338; Lviv Polytech. Natl. Univ., Lviv 79013, Ukraine; Eng.) -R. Langenstrassen 31-132