Chemistry of esters of keto acids of the acetylene series. X. Addition of amines to 3-phenylethynyl-1-quinoxalone

The reaction of 3-phenylethynyl-2-quinoxalones with aliphatic and aromatic amines gives alkyl(aryl)imines of 3-phenacylidene-2-quinoxalone, the structures of which were proved by alternative synthesis from 3-phenacylidene-2-quinoxalone and the appropriate amines.See [1] for communication IX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 276–277, February, 1976.     

Synthesen von α,β-ungesättigten 2-(2-Oxo-benzazolin-3-yl)-3-hydroxy-dithio-carbonsäure-alkylestern und entsprechend substituierten Keten-S,S-acetalen sowie deren Kristall- und Molekülstruktur

Summary The new alkyl 2-(2-oxo-benzazoline-3-yl)-3-hydroxy dithiocrotonates and dithiocinnamates4 and the corresponding ketene dithioacetals2 and5 are obtained by dithiocarboxylation of the 3-acceptormethyl substituted benzazoline-2-ones1 or3. Alkylation at room temperature gives compounds4 whereas at higher alkylation temperature2 or5 are formed. The results of X-ray analyses performed for methyl 3-hydroxy-p-chloro-dithiocinnamate4d and of N-[1-(4-chloro-benzoyl)-2,2-bis(methylthio)-vinyl]-benzothiazoline-2-one5e are discussed.

     

Quantum chemical calculations of the molecular structure of diphenylguanidine and experimental studies of its tautomerism in solution

MNDO-PM3 and AM1 quantum chemical calculations of the molecular structure of N,N′-diphenyl-guanidine (DPG) prove that the molecule preferably exists as an asymmetric tautomer with a basic center C = N−. IR and UV spectral data, dipole moments, and average molecular weights of DPG solutions in nonpolar and low-polar solvents confirm the results of calculations, indicating formation of hydrogen-bonded cyclic self-associates of DPG in solution. Translated fromZhumal Strukturnoi Khimii, Vol. 39, No. 4, pp. 618–625, July–August, 1998.     

Substitutive sulfotrioxidation of unsaturated and araliphatic organofluorine compounds

Conclusions Reaction of SO₂ or SO₃/[B₂O₃] with terminal fluoroolefins or fluoroalkylbenzenes gives the corresponding fluoroalken-2-yl fluorosulfates and fluorobenzyl fluorosulfates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2791–2795, December, 1982.     

Functional derivatives of thiophene. I. Synthesis and 1H-NMR spectra in the 2-aminothiophene series

The preparation of 2-amino-5-nitrothiophene, 2-formamido-5-nitrothiophene, 2-acetamido-5-nitrothiophene and 2-t-butyloxycarbonylamino-5-nitrothiophene are described. Abnormal values of the coupling constants J_3.4 had been observed in the ¹H-nmr spectra of compounds obtained.