ChemInform Abstract: NEUARTIGE SYNTH. VON PYRIDINEN AUS DIACETYLEN

Diacetylene: a candidate for industrially important reactions

“…The reaction of diacetylene with semicarbazide, which manifests much weaker basic properties than hydrazines, yields a mixture of 3-and 5-alkylpyrazolecarboxamides (58,59). 175 The amides 58, which are irreversibly isomerised into the adducts 59 under these conditions, are the main reaction products. 175 Other 1,3-diynes produce exclusively amides of the type 59.…”

“…175 The amides 58, which are irreversibly isomerised into the adducts 59 under these conditions, are the main reaction products. 175 Other 1,3-diynes produce exclusively amides of the type 59. 175 The presence of a pyrazole ring was confirmed 175 by acid hydrolysis of the adducts 59, which was accompanied by decarboxylation and formation of pyrazoles 60.…”

“…175 Other 1,3-diynes produce exclusively amides of the type 59. 175 The presence of a pyrazole ring was confirmed 175 by acid hydrolysis of the adducts 59, which was accompanied by decarboxylation and formation of pyrazoles 60. Synthesis of 1-guanyl-3-methylpyrazole (yield 86%) from pyrazole 55 was described.…”

“…Synthesis of 1-guanyl-3-methylpyrazole (yield 86%) from pyrazole 55 was described. 176 Pyrazole-1-carboxylic acid derivatives are used as pesticides 177 and insecticides. 178 Functionalised pyridines were prepared based on diacetylene and compounds containing a weakly nucleophilic nitrogen atom and an active CH-component (e.g., acetylacetoneimine and ethyl b-aminocrotonate).…”

“…178 The IR spectra of compounds 61 and 62 contain bands corresponding to stretching vibrations of the pyridine ring (1560, 1580 cm 71 ), ester (1076 cm 71 ) and carbonyl (1721 cm 71 ) groups. 176,178 The protons of the pyridine ring in the 1 H NMR spectrum of compound 62 resonate as two doublets in the lowfield region at d 8.24 and 6.84 (J = 5.2 Hz). The former belongs to the proton at the C(6) atom, which is especially strongly…”