Chromones, 4-thio-, reaction with

Chloroperoxidase catalysis by, 58, 302 in chlorination of pyrazoles, 57, 337 Chlorophyll, thioaldehyde synthetic intermediate to, 55, 3 Chlorosulfonyl isocyanate, reaction with 2-arylhydrazono-3-oxobutanoate, 59, 148 Chromatography, of [l,2,4]triazolo[l,5-a]-pyrimidines, 57, 106 Chrom-3-enes, see 2//-l-Benzopyrans Chromium tricarbonyl complexes of 3,5-diphenyl-l-(alkyl- or oxido-)-thiabenzenes, 59, 206, 227 indoles, lithiation of, 56, 181, 184 of pyridine, 58, 160 pyridines, lithiation of, 56, 230, 239 of 2f/-thiopyrans, 59, 227 Chromones, see l-Benzopyran-4-ones Cinnamonitrile, a-cyano-, condensations with thio-, seleno-amides, 59, 184, 186 Cinnoline, nitration, MO calculation, 59, 302... 

Chromone derivatives and their analogues 704 and 705 were used for synthesis of 4-fluoroalkylpyrimidines. In both cases, reaction with NCN binucleophiles was accompanied with recyclization of the y-(thia)pyrone ring to give (2-(thio) hydroxyphenyl)-substituted pyrimidines or their analogues (Table 37). 

Hydroxyalkyl derivatives of seleno- and thio- chromones can be formed by the reaction of aldehydes with appropriate propynones in which an intramolecular Michael reaction is followed by an aldol condensation (Scheme 9) <02TL7039>. 

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