Mass spectral fragmentation pattern of 2,3-dimethyl- and 2-methyl-3-phenyl-4-arylazoisoxazol-5-ones

2,3-Dimethyl-4-arylazoisoxazol-5-ones and 2-methyl-3-phenyl-4-aryiazoisoxazol-5-ones undergo considerable fragmentation on electron impact. The base peaks in the mass spectra are at mass 56 and 118 respectively attributed to the N-methylacetonitrile cation and the N-methylbenzonitrile cation.     

Reaction of metallo S-alkyl N-cyanodithioiminocarbonates and alkyl N-cyanocarbamates with hydrazine. A novel preparation of 5-amino-3-mercapto-1,2,4-triazole

Metal salts of S-alkyl-N-cyanodithioiminocarbonates 7 react as electrophiles with hydrazine hydrate to form 5-amino-3-mercapto-1H-1,2,4-triazole 1 . The novel 4-cyanothiosemicarbazide 9 is proposed as the intermediate which cyclizes to the aromatic triazole. The rate determining step is addition of hydrazine to the iminocarbonate and is second order. Other nucleophiles such as substituted hydrazines and amines failed to react. Exchange of either or both sulfurs with oxygen leads to decomposition or mixtures of products.     

Mass spectral fragmentation pattern of 2,2′-Bipyridyls. Part X. trans-1,2-Di-(2-pyridyl)ethylene

The base peak in the mass spectrum of trans-1,2-di-(2-pyridyl)ethylene is due to the M-1 ion. A major fragmentation route involves loss of HCN from the M-1 ion. Another important pathway involves rupture of one of the bonds linking a pyridine ring with the central CH?CH group.     

Mass spectral fragmentation pattern of 4,4′-bipyridines. Part II. 4,4′-oxybispyridine and 4,4′-thiobispyridine

The mass spectra of 4,4′-oxybispyridine and 4,4′-thiobispyridine are reported. In the former the base peak is due to the molecular ion and the fragmentation routes involve loss of H, CO, HCN, C₂H₂N and C_sHO from the molecular ion as well as rupture of the central bonds. In the latter the base peak is also due to the molecular ion and the fragmentation routes involve loss of H, CS, S, HCN and C₂HS as well as central bond rupture.     

Mass spectral fragmentation pattern of 2,2′-bipyridyls. Part II. 5-Hydroxy- and 5-alkoxy-2,2′-bipyridyls

The mass spectra of 5-hydroxy-, 5-methoxy-, 5-ethoxy- and 5-propoxy-2,2′-bipyridyls are reported. The fragmentation proposals are supported by high resolution mass measurements and metastable transitions.     

Mass spectral fragmentation pattern of 2,2′-bipyridyls. Part XII. 2,2′-Selenodipyridine

The mass spectrum of 2,2′-selenodipyridine obtained by electron impact is reported. The base peak in the spectrum is due to the C₅H₄N⁺ ion formed principally by rupture of the central bonds. The molecular ion gives rise to a peak of 50% of the intensity of the base peak. Other fragmentations include loss of H, Se and CSe from the molecular ion and HCN from the M-1 ion.     

Mass spectral fragmentation pattern of 2,2′-bipyridyls Part XI. 2,2′-Iminodipyridine

The base peak in the mass spectrum of 2,2′-iminodipyridine is due to the M-1 ion. There are several minor fragmentation routes from the molecular ion but the principal pathway involves rupture of the central bonds. J. Heterocyclic Chem., 14, 1103 (1977)     

Synthesis,polarography and herbicidal activity of quaternary salts of 2-(4-pyridyl)-1,3,5-triazines, 5-(4-pyridyl)pyrimidine, 2-(4-pyridyl)pyrimidine and related compounds

2-(4-Pyridyl)-1,3,5-triazine, 2-(4-pyridyl)-4-methyl-1,3,5-triazine, 2-(4-pyridyl)-4,6-dimethyl-1,3,5-triazine and 2-(4-pyridyl)pyrimidine have been prepared by modification of established triazine and pyrimidine syntheses. These compounds and some of their relatives have been converted to quaternary pyridinium salts. The polarographic reduction potentials of the salts in aqueous solution are pH dependent. The activity of the salts as post-emergent herbicides is reported.