86984-35-2Relevant articles and documents
STEREOCHEMICAL STUDIES-54 SATURATED HETEROCYCLES-35
Stajer, Geza,Szabo, A. Enikoe,Fueloep, Ferenc,Bernath, Gabor,Kalman, Alajos,et al.
, p. 1829 - 1836 (1983)
cis and trans-5,6-Trimethylene-3,4,5,6-tetrahydro-1,3-oxazin-2-ones and thiones (11-20) were synthesized from cis and trans-2-aminomethylcyclopentanols (6-10) by reaction with urea, ethyl chloroformate, carbon disulphide, or thiophosgene.The cyclization reactions were also successful with the trans-amino-alcohols, at variance with earlier literature data relating to 1,2-disubstituted 1,3-bifunctional trans-cyclopentane derivatives.X-ray diffraction analysis of trans-5,6-trimethylene-3,4,5,6-tetrahydro-1,3-oxazine-2-thione (17) shows that the exocyclic CS sp2 bond takes part in a co-planar delocalized p?-p? bond system formed on the S(10), O(1), N(3) and C(2) atoms, and consequently both the C(2)-N(3) and C(2)-O(1) bonds gain some multiple bond character.The endocyclic bond angles at C(2) and N(3) are significantly opened, compared with those in related heterocycles.Of the bonds in the six-membered hetero ring, C(5)-C(6) is significantly shortened .The remarkable ring closure reaction of the trans cyclopentane derivatives can be explained by the above findings. 1H NMR data on compounds 11-20 suggest conformationally homogeneous systems and the predominance of the O-inside conformers of the cis isomers.
