Acetals and vinyl ethers of unsaturated aldehydes and ketones in the new syntheses of heterocyclic compounds: XII. New alternatives of acid condensation of cyclohexane-1,4-diones with hydroxyarylaldehydes under dehydration conditions. Fluorecence spectra of the products
Ep. Olekhnovich et al., Acetals and vinyl ethers of unsaturated aldehydes and ketones in the new syntheses of heterocyclic compounds: XII. New alternatives of acid condensation of cyclohexane-1,4-diones with hydroxyarylaldehydes under dehydration conditions. Fluorecence spectra of the products, RUSS J ORG, 37(4), 2001, pp. 527-538
1,3-Diethoxy-2-R-5,5-R-1,R-1-1-cyclohexenylium perchlorates in condensation
with 2-hydroxyaryl-aldehydes under dehydration conditions give rise to 3-e
thoxy-1,2-dihydroxanthylium perchlorates that with the second molecule of 2
-hydroxyarylaldehyde afford 13H-chromeno[3,2-b]xanth-5-ylium perchlorates,
and with primary and secondary amines yield 3-(R-2,R-3-amino)-1,2-dihydroxa
nthylium perchlorates. The condensation of 2-bromodimedone with salicylalde
hydes in triethyl orthoformate and perchloric acid medium furnished 6-bromo
-13,13-dimethyl-13H-chromeno[3,2-b]xanth-5-ylium perchlorates. The latter c
ompounds show strong fluorescence in 530-630 nm region with 0.48-0.98 quant
um efficiency. Under similar conditions the dimedone and 2-acetyldimedone a
fford with 2-hydroxyarylaldehydes tris-condensation products: 2,10-dimethox
y-6-(3-methoxy-6-oxo-2,4-cyclohexadienylidenemethyl)-7,7-dimethyl-7H-chrome
no[2,3-a]-xanth-13-ylium perchlorate and 2,10-dimethoxy-6-(6-methoxychromyl
ium-2-yl)-13,13-dimethyl-13H-chromeno[3,2-b]xanth-5-ylium diperchlorate res
pectively.