0000000000322821
AUTHOR
Gurnos Jones
The synthesis of thienocycloheptenoindoles
A synthesis of the methylthieno[3,2-c]cyclohepteno[b]indole 7 from 2-methylthieno[3,2-b]cycloheptanone 3 is described. Unsuccessful attempts to prepare the isomeric thienocycloheptenoindole system present in formula 2, from the dihydrobenzothiophenone 8, and from derivatives of 5-(2-thienyl)-4-oxopentanoic acid, 17 and 18, and from N-benzylcycloheptindol-1-one 22 were unsuccessful. The preparation of 4,5-dihydro-2-phenyl-1-thienylmethyl-3H-pyridazin-3-one 20 and of the 5-aminopyrazole 21 are reported.
Triazolopyridines. 14. Substitution reactions of 7-amino[1,2,3]triazolo[1,5-a]pyridines.
Abstract Reaction between 7-aminotriazolopyridines 1 or 2 and sulphuric acid gives hydroxyalkylpyridines 3 and 4 ; bromination gives brominated pyridine 5 or triazolopyridine 6. The anions from amines 1 or 2 are ambident, acylating on N but alkylating on N or on C6; in the latter case triazolylalkenylcyanides 16 – 20 or the 6,6-dialkylated derivative 19 are obtained. An X-ray diffraction study has confirmed structure 19.
Cycloaddition reactions of 2-vinylthiophen
Abstract Cycloaddition reactions between 2-vinylthiophen and the dienophiles maleic anhydride, dimethyl acetylenedicarboxylate,' methyl propiolate, and methyl acrylate, are reported. Products include simple benzo[b]thiophen carboxylates (6, 13, 17) and reduced derivatives (3, 4, 18). The acetylenic dienophiles also gave a dihydrobenzthienyl-acrylate (16) or -fumarate (11), and the dithienylcyclohexene esters (7) and (14).
Mechanistic studies of the ring opening reactions of [1,2,3]triazolo[1,5-a]pyridines
Abstract A mechanism with radical intervention is proposed for the opening of the triazole ring in [1,2,3] triazolo[1,5-a]pyridines which results in the production of 2- or 2,6-disubstituted pyridines.
Nucleophilic substitutions on bromotriazolopyridines - an improved route to 2,6-disubstituted pyridines and to 1,3-disubstituted isoquinolines
Abstract A regiospecific synthesis of 2,6-disubstituted pyridines and of 1,3-disubstituted isoquinolines is described.
Triazolopyridines. Part 8.1 Nucleophilic substitution reactions of 5-bromo[1,2,3]triazolo[5,1-a]isoquinoline and 7-bromo[1,2,3]-triazolo[1,5-a]pyridine
Abstract Nucleophilic substitution of 5-bromotriazoloisoquinoline (3) and of 7-bromo-3-methyltriazolopyridine (6) proceeds readily to give a range of 5-substituted triazoloisoquinolines (4a)-(4e), and of 7-substituted triazolopyridines (7a)-(7h) respectively. Triazoloisoquinolines have been converted into 1,3-disubstituted isoquinolines (11)-(13), (15), and (16), and triazolopyridines into 2,6-disubstituted pyridines (17)-(19). Of secondary amine nucleophiles, only piperidine reacted with 7-bromo-3-methyltriazolopyridine (6) to give the 7-substituted derivative (7g). A second product in this reaction was a 2,6-disubstituted pyridine (8); the similar compounds (20)-(24) were the only product…
Cycloaddition reactions of 3-vinylthiophen
Abstract Cycloaddition reactions between 3-vinylthiophen and the dienophiles maleic anhydride, methyl acrylate, dimethyl acetylene - dicarboxylate, and methyl propiolate give products including methyl benzo[b]thiophen-7-carboxylate (11) and its dihydroderivative (10), the 6,7-dicarboxylic acid (3), its dimethyl ester (7) and dihydroester (6); the naphtho[a,b]dithiophen (14), and the novel ethano bridged benzo[b]thiophen (15).
Triazolopyridines. 18. Nucleophilic substitution reactions on triazolopyridines; a new route to 2,2′-bipyridines
Abstract The synthesis of some 5-, 6-, and 7-halogenotriazolopyridines is described, and their reactions with nucleophiles. The formation of 7,7′-bitriazolopyridines provides a new synthesis of 2,2′-bipyridines.
Triazolopyridines. Part 9. The synthesis of7-amino(1,2,3)triazolo(1,5-a)pyridines
Abstract Regiospecific lithiation of (1,2,3) triazolo(1,5-a)pyridines (1) and (4) with subsequent reaction with styryl azide gave small yields of the 7-aminotriazolopyridines (6) and (7). A longer larger scale synthesis of compounds (6) and (7) is described giving overall yields of 17 and 25%, starting from 2-amino-6-methyl (9) or 2-amino-6-ethyl pyridine (19).
The Chemistry of the [1,2,3]Triazolo[1,5-a]pyridines: An Update
Publisher Summary This chapter discusses the recent advancement in the chemistry of [1,2,3] triazolo[1,5-a]pyridines. It describes new discoveries in the physical properties and theoretical chemistry, focusing on synthesis of [1,2,3]triazolo[1,5-a]pyridine system, synthesis of novel aryltriazolopyridines, chiral ligands from [1,2,3]triazolo[1,5-a]pyridines, pyridylcarbene formation from triazolopyridines, ring-chain isomerization on [1,2,3]triazolo[1,5-a]pyridines, and novel pyridylcarbonylpyridines. All triazolopyridines have interesting ligand properties to form polynuclear complexes with different metal ions. X-ray single-crystal studies, magnetic, photo-magnetic, and colorimetric measur…
A remarkable rearrangement during reaction between triazolopyridinium ylides and dimethyl acetylenedicarboxylate
Abstract The ylides from 2-acylmethyltriazolopyridinium salts ( 1 ) react with dimethyl acetylenedicarboxylate in toluene solution to give the 7-pyrroleninylpyrazolo[1,5-a]pyridines ( 5 ).