The triphenylphosphine – carbon tetrahalide (Br, Cl) system transforms N′-benzoyl-N-arylhydrazines (1), N,N-dimethyl-, and N-methyl-N-phenyl-N′-benzoylhydrazines (3) into the corresponding hydrazonyl halides 2 and 4.Tribromomethyltriphenylphosphonium bromide (7), formed by reacting triphenylphosphine with carbon tetrabromide, is capable of transforming N′-benzoyl-N-phenylhydrazine (1a) into the corresponding hydrazonyl bromide (2b) in the presence of triphenylphosphine.

2,2-Dimethylindanone-180. 2,2-Dimethylindanone (0.11 g) in 5.0 mL of aniline was refluxed for 12 h with 0.20 mL of BFs-EtaO. The resulting crude solid was recrystallized from ether to yield 0.08 g of 2,2-dimethylindan-1 -phenylimine: mp 43-46 °C; IR (CHCI3) 2960,

Appearance energies and metastable peak shapes for methyl loss from the molecular ions of cyclohexene, methylcyclopentenes, methylenecyclopentane, bicyclo[3.1.0]hexane, and 2-methyl-1,4-pentadiene indicate that they have a common reaction pathway which produces [cyclopentenium]+ as the daughter ion at threshold.From measurements of appearance energies and from relative peak abundances and kinetic energy releases for the metastable losses of CH3• and labelled methyl from the deuterium labelled cyclic [C6H10]+• molecular ions it was concluded that: (a) H/D mixing in [cyclohexene]+• occurs in the intact ring prior to a concerted methyl extrusion; (b) [methylcyclopentenes]+• loses methyl without any H/D mixing at or near to threshold by a straight C—C cleavage, possibly via the 3-isomer. Methyl losses involving H/D mixing are preceded by ring opening which has an activation energy of ca. 1 eV. However, [cyclopentenium]+• is again the daughter ion; (c) methylenecyclopentane and bicyclo[3.1.0]hexane molecular ions isomerize to methylcyclopentenes prior to methyl loss.H/D mixing (prior to methyl loss) in the molecular ion 1,1-2H2-2-methyl-1,4-pentadiene takes place before cyclisation to methylcyclopentene.

Reaction of hydrazonyl halides with (substituted) thioureas and thiosemicarbazides gives mainly 1,3,4-thiadiazolines, the stronger base being preferentially eliminated in the process. Similar reactions in presence of triethylamine give C-amino- and C-hydrazino-1,2,4-triazoles, respectively, together with the hydrazonyl sulfide.Potassium cyanide cleavage of a hydrazonyl disulfide gives the corresponding 1,3,4-thiadiazoline and thiohydrazide.

Aromatic hydrazonyl halides ( I ) , treated successively with triethylamine and hydrogen sulfide -triethylamine, give N-aryl-N'-thioaroylhydrazines ( 3 ) as primary products, which can be isolated in many cases. Depending on conditions, further reaction m a y occur to give sym-hydrazonyl sulfides.Both sym-and unsyrn-hydrazonyl sulfides are available from reaction of appropriate hydrazonyl halides and N-aryl-N'-thioaroylhydrazines in presence of triethylamine.The product of oxidation of N-phenyl-N'-thiobenzoylhydrazine under various conditions is confirmed as the corresponding hydrazonyl disulfide rather than N-pheny1-N'-thiobenzoyldiimide. This report is of considerable interest in connection with current work in our respective laboratories on 1,3,4-thiadiazol-2-enes (2), 4H-1,3,4-benzothiadiazines, and hydrazonyl sulfides (3) and has prompted the investigation of a corresponding synthesis of N-aryl-Nf-thioaroylhydrazines (3) and, from these compounds and hydrazonyl halides (I), a synthesis of hydrazonyl sulfides (4) (see Scheme 1).The hydrazonyl halides used in this study were all known compounds (3-11) and initially, in examining reaction 2, the order of addition of reagents corresponded with that used by Walter and Reubke (1). Typically (Procedure A), NEt, (1 equiv.) in CHCl, was added to ldin CHCI,. After 25 s, a solution of H,S-NEt, in CHCI,, prepared by saturating NEt, (2 equiv.) in CHC1, with H2S, was added. After 2 h, acidification gave 3d in 82% yield. However, if the interval between addition of the NEt, and H2S-NEt, solutions was extended to 4 min, the product isolated was the hydrazonyl sulfide (4d) (93% yield). Mixtures of 3d and 4d were obtained after intermediate intervals in the range 25 s to 4 min. Similar patterns were observed with other hydrazonyl halides, though in yet other cases the product distribution was not detectably time dependent in the intervals examined. For example, l a (intervals, 25 s For personal use only.