Abstract:Das IR-Spektrum von (2) enthalt alle fur Thioacylhydrazine charakteristischen Banden [31. Die dreifache Bande bei 2700 bis 2780 cm-1 im IR-Spektrum von (3) fuhren wir auf eine Gruppierung @NHR2 zuruck; Dimethylhydrazin-hydrochlorid zeigt in diesem Bereich ebenfalls eine aufgespaltene Bande. Die starke Bande bei 1460 cm-1 schreiben wir einer vorwiegenden C-N-Doppelbindung zu.Fur die Betainstruktur (3) sprechen die pKa-Werte der beiden Isomeren, die photometrisch bestimmt wurden. (2) :Der Wert pKa2 = 10,4 (2) wu… Show more
“…Information about the synthesis and properties of partially saturated [1,2]dithiolo[3,4-b]pyridines is even more scarce. Thus, the only known synthesis of 4,5,6,7-tetrahydro[1,2]dithiolo[3,4-b]pyridine is not general and is based on the reaction of heterocyclic 1,4-dipol 11 with sulfur [ 15 ]. Finally, the reaction of dithiomalondianilide (N,N’-diphenyldithiomalondiamide) 12 with arylmethylene malononitriles yielded 4,7-dihydro[1,2]dithiolo[3,4-b]pyridines 13 [ 16 ] ( Scheme 1 ).…”
The reaction between dithiomalondianilide (N,N’-diphenyldithiomalondiamide) and alkyl 3-aryl-2-cyanoacrylates in the presence of morpholine in the air atmosphere leads to the formation of alkyl 6-amino-4-aryl-7-phenyl-3-(phenylimino)-4,7-dihydro-3H-[1,2]dithiolo[3,4-b]- pyridine-5-carboxylates in 37–72% yields. The same compounds were prepared in 23–65% yields by ternary condensation of aromatic aldehydes, ethyl(methyl) cyanoacetate and dithiomalondianilide. The reaction mechanism is discussed. The structure of ethyl 6-amino-4-(4-methoxyphenyl)-7-phenyl-3-(phenylimino)-4,7-dihydro-3H-[1,2]dithiolo[3,4-b]pyridine-5-carboxylate was confirmed by X-ray crystallography. Two of the prepared compounds showed a moderate growth-stimulating effect on sunflower seedlings. Three of the new compounds were recognized as strong herbicide safeners with respect to herbicide 2,4-D in the laboratory and field experiments on sunflower.
“…Information about the synthesis and properties of partially saturated [1,2]dithiolo[3,4-b]pyridines is even more scarce. Thus, the only known synthesis of 4,5,6,7-tetrahydro[1,2]dithiolo[3,4-b]pyridine is not general and is based on the reaction of heterocyclic 1,4-dipol 11 with sulfur [ 15 ]. Finally, the reaction of dithiomalondianilide (N,N’-diphenyldithiomalondiamide) 12 with arylmethylene malononitriles yielded 4,7-dihydro[1,2]dithiolo[3,4-b]pyridines 13 [ 16 ] ( Scheme 1 ).…”
The reaction between dithiomalondianilide (N,N’-diphenyldithiomalondiamide) and alkyl 3-aryl-2-cyanoacrylates in the presence of morpholine in the air atmosphere leads to the formation of alkyl 6-amino-4-aryl-7-phenyl-3-(phenylimino)-4,7-dihydro-3H-[1,2]dithiolo[3,4-b]- pyridine-5-carboxylates in 37–72% yields. The same compounds were prepared in 23–65% yields by ternary condensation of aromatic aldehydes, ethyl(methyl) cyanoacetate and dithiomalondianilide. The reaction mechanism is discussed. The structure of ethyl 6-amino-4-(4-methoxyphenyl)-7-phenyl-3-(phenylimino)-4,7-dihydro-3H-[1,2]dithiolo[3,4-b]pyridine-5-carboxylate was confirmed by X-ray crystallography. Two of the prepared compounds showed a moderate growth-stimulating effect on sunflower seedlings. Three of the new compounds were recognized as strong herbicide safeners with respect to herbicide 2,4-D in the laboratory and field experiments on sunflower.
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