Pyrylium synthesis

Enamines are also potential ketones and accordingly have been used as the ketonic component in this type of pyrylium synthesis (63AG(E)394). The initial adducts, which form pyrylium salts on treatment with perchloric acid, are similar to those derived from secondary amines and pyrylium salts. The significant feature of this variant is that it gives access to pyrylium compounds which are unsubstituted at the 4- and 6-positions but which carry substituents at C-2 and C-5. More conventional enamines, such as 1-piperidinocyclohexene, afford bicyclic pyrylium salts (652), whilst polycyclic salts (653) result if cyclic chlorovinyl ketones are used. 

Benzofuro[3,2-c]pyrroles reduction, 4, 1079 Benzofuro[3,2-6]pyrylium salts synthesis, 4, 995 Benzofuro[2,3-c][l, 2]thiazine... 

H-l-Benzopyran-4-ones — see Chromones 4H-l-Benzopyran-4-ones, 2-phenyl — see Flavones Benzopyranopyrazoles synthesis, S, 317, 341 Benzopyrano[4,3-c]pytazol-4-one synthesis, 3, 712 Benzopyrano[4,3-6]pyridine synthesis, 3, 712 Benzopyrano[4,3-ii]pyrimidine synthesis, 3, 712 Benzopyrans nomenclature, 1, 23 pyrylium salt synthesis from, 3, 873 reactions... 

Wolff rearrangement, 7, 193 pyrylium salt synthesis from, 3, 871... 

Naphtho[l,2-h]pyrylium salts, 5,6-dihydro-2,4-diphenyl-synthesis, 3, 869 Naphtho[2,l-h]pyrylium salts synthesis, 3, 866 Naphthoquinolines, tetrahydro-synthesis, 2, 469 N aphtho[ 1,2-7]quinolines Skraup synthesis, 2, 467... 

K-pyran synthesis from, 3, 761-762 pyridazine synthesis from, 3, 54 pyrylium salt synthesis from, 3, 872 reduced, 2, 45... 

Pyrylium perchlorate, 2,4,6-triphenyl-hydrolysis, 3, 741 nitration, 3, 649 reactions with alkali, 3, 652 with methoxides, 3, 652 with piperidine, 3, 655 synthesis, 3, 869... 

Pyrylium salts alkyl groups reactivity, 3, 662 aromaticity, 3, 640 arylammes from, 3, 657 benzenoid compounds from, 3, 656, 658 benzisoxazol-3-yl-synthesis, 6, 124 bicyclic... 

Pyrylium salts, 3-acetyl-2,4,6-trimethyl-crystallography, 3, 625 Pyrylium salts, 3-alkoxymethyl-synthesis, 3, 865 Pyrylium salts, alkyl-deprotonation, 2, 51 reactions, 2, 50 Pyrylium salts, 2-amino-reactions, 2, 55 Pyrylium salts, 4-amino-deprotonation, 2, 55... 

Pyrylium salts, 2,6-dimethoxycarbonyl-synthesis, 3, 873 Pyrylium salts, 2,6-diphenyl-synthesis, 3, 865, 866 Pyrylium salts, 3-ethoxycarbonyl-synthesis, 3, 870... 

Pyrylium salts, 2,3,4,6-tetramethyl-synthesis, 3, 868 Pyrylium salts, 2,4,6-trialkyl-oxidation, 3, 650 Pyrylium salts, 2,4,6-triaryl-synthesis, 3, 870 Pyrylium salts, 2,4,6-trimethyl-deuteration, 3, 649 synthesis, 3, 861, 868, 873 Pyrylium salts, 2,4,6-trimethyl-4-styryl-reactions... 

Selenolopyrylium salts, 4, 1034—1036 Selenolo[2,3-c]pyrylium salts synthesis, 4, 969 Selenolo[3,2-b]pyrylium salts synthesis, 4, 1035 Selenolo[3,2-c]pyrylium salts synthesis, 4, 969 Selenoloseknophenes electrophilic substitution, 4, 1057 NMR, 4, 13 synthesis, 4, 135 UV spectra, 4, 1044 Selenoloselenophenes, alkyl-synthesis, 4, 967 Selenolo[2,3-b]selenophenes ionization potentials, 4, 1046 Selenolo[3,2- bjselenophenes dipole moments, 4, 1049 ionization potentials, 4, 1046 structure, 4, 1038, 1039 Selenolo 3,4-f)]selenophenes H NMR, 4, 1042 synthesis, 4, 1067 Selenolo[3,4-c]selenophenes non-classical reactions, 4, 1062 synthesis, 4, 1076 Selenolothiophenes electrophilic substitution, 4, 1057 H NMR, 4, 1041 UV spectra, 4, 1044 Selenolo[2,3- bjthiophenes... 

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