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Fragmentation of 1-alkyl(cycloalkyl, alkoxyalkyl)-5-[(alkyl, allyl, benzyl)sulfanyl]-1H-pyrrol-2-amines under electron impact (70 eV) and chemical ionization (with methane as reactant gas) has been studied for the first time. All the examined compounds under electron impact generated the molecular ion [M]+· (Irel 5–90%) whose primary fragmentation involved mainly cleavage of the C–S bond in the SR4 substituent with elimination of R4 radical (except for 1-isopropyl- and 1-cycloalkyl-1H-pyrrol-2-amines). The main pathway of the decomposition of 1-isopropyl(cycloalkyl)-N,N-dimethyl-5-[(methyl, allyl)sulfanyl]-1H-pyrrol-2-amines was cleavage of the C–N bond with both elimination of the R1 radical from the pyrrole nitrogen atom and fragmentation of the pyrrole ring through elimination of imine (or aziridine) molecule and formation of odd-electron [M – NR1]+· radical cation. Chemical ionization of the title compounds involved protonation, charge exchange, and electrophilic addition processes and elimination of Me (Et) and SMe (SEt) radicals from the [M + H]+ ions.

The fragmentation of previously inaccessible alkyl [(5-amino-1H-pyrrol-2-yl)sulfanyl]acetates under electron (70 eV) and chemical (reactant gas methane) ionization conditions was studied for the first time. Under electron ionization, all the studied compounds form a molecular ion (Irel 7–100%), the main primary fragmentation pathway of which is associated with the C–S bond cleavage in the sulfanyl group and elimination of the ester fragment (R4OCOCH2) in the form of a radical. The chemical ionization of alkyl [(5-amino-1H-pyrrol-2-yl)sulfanyl]acetates is characterized by protonation, recharging, and electrophilic addition. The base peak belongs to an [M + H]+ ion. Chemical ionization is accompanied by the elimination of an R4OCOCH2 radical from the M+• and [M + Et]+ ions and an R4OCOCHS molecule from the M+• and [M + H]+ ions.

According to the matrix-free laser desorption/ionization time-of-flight mass spectrometric data, the reaction of benzimidazole with bis(iodomethyl)tetramethyldisiloxane at different temperatures leads to the formation of linear and cyclic organosilicon systems containing benzimidazole fragments. The structures of the major and minor products were determined by analysis of the fragmentation patterns in the field-free space.

Electron impact (70 eV) and chemical ionization (methane as reactant gas) mass spectra of 1-alkyl- and 1-[2-(vinyloxy)ethyl]-5-(prop-2-yn-1-ylsulfanyl)-1H-pyrrol-2-amines have been studied for the first time. The title compounds under electron impact form stable molecular ions which decompose mainly along pathways typical of the molecular ions derived from the corresponding intramolecular cyclization products, 7-alkyl- and 7-[2-(vinyloxy)ethyl]-2,7-dihydrothiopyrano[2,3-b]pyrrol-6-amines. In addition, fragment ions that could be formed only via decomposition of unrearranged molecular ion were detected. The main fragmentation pathway of their molecular ions involves cleavage of the N1-CAlk bond with the formation of stable [M − R3]+ ions (Irel 85–100%) {except for N,N-diethyl- and N,N-dipropyl-1-[2-(vinyloxy)emyl]-5-(prop-2-yn-1-ylsulfanyl)-1H-pyrrol-2-amines}. The results of quantum chemical calculations at the B3LYP/6-311+G(d,p) level of theory are consistent with the experimental data. In the chemical ionization mass spectra of 5-(prop-2-yn-1-ylsulfanyl)-1H-pyrrol-2-amines, the major peaks were those corresponding to M+· (Irel 65–100%) and [M + H]+ (Irel 75–100%). The title compounds have been found to undergo partial (5–10%) thermally induced isomerization to 5-(prop-1-yn-1-ylsulfanyl)-1H-pyrrol-2-amines under the chemical ionization conditions.

Fragmentation of N, N-dialkyl-7-[alkyl and 2-(vinyloxy)ethyl]-2,7-dihydrothiopyrano[2,3-b]pyrrol-6-amines under electron impact (70 eV) and chemical ionization (methane as reactant gas) has been studied. The electron impact ionization of these compounds gives rise to stable molecular ions which decompose according to two main pathways. The major pathway involves cleavage of the N7—CAlk bond with elimination of the alkyl radical. The minor pathway is expulsion of alkyl radical from the amino nitrogen atom in the 6-position. The chemical ionization of 2,7-dihydrothiopyrano[2,3-b]pyrrol-6-amines characteristically involves protonation and electrophilic addition processes with the most abundant ion being [M + H]+.

Electron impact (70 eV) and chemical ionization (methane as reactant gas) mass spectra of alkyl 5-amino-3-methyl-4-(1H-pyrrol-1-yl)thiophene-2-carboxylates have been studied for the first time. All compounds, except for tert-butyl thiophene-2-carboxylate, under electron impact give rise to stable molecular ions which decompose along two paths, depending on the site of positive charge localization (at the ester fragment or amino nitrogen atom). The main fragmentation pathway of the molecular ions is elimination of alkoxy radical from the ester group. Chemical ionization of alkyl 5-amino-3-methyl-4-(1H-pyrrol-1-yl)-thiophene-2-carboxylates involves protonation and electrophilic addition with the base peak corresponding to the [M + H]+ ion.

The major and minor products of the reaction of imidazole with bis(iodomethyl)tetramethyldisiloxane have been identified, and their main fragmentation pathways have been determined, by matrix-free nano-assisted laser desorption/ionization mass spectrometry (NALDI TOF/TOF).

For the first time decomposition was investigated of 4-alkoxy-5-amino-3-methylthiophene-2-carbonitriles under the conditions of electronic (70 eV) and chemical (reagent gas methane) ionization. At the electronic ionization the compounds under study [except for 4-(1-ethoxyethoxy) and 4-(ferrocenylmethoxy) derivatives] form stable molecular ions that decompose mainly by the cleavage of an alkyl radical from the alkoxy-substituent. Further fragmentation of the arising ion [M–Alk]+ depends on the substituent nature in the amino group. In the mass spectrum of 4-(ferrocenylmethoxy)-substituted thiophene peaks of the ion [FcCH2]+ and its fragmentation products prevail. In the mass spectra of chemical ionization predominant peaks belong to ions M+·, [M + H]+ and [M + C2H5]+, and fragment ions are absent.

The molecular structure of the selenides of [R2P(Se)]2Se type has been systematically studied on example of bis(dicyclohexylselenophosphinyl)selenide, [Cy2P(Se)]2Se. This selenide has been synthesized in 65% yield by oxidation of Cy2PH with elemental selenium in 1:2 M ratio. Its structure has been investigated by X-ray diffractometry (XRD), NMR, FT-IR and MALDI-TOF/MS techniques. In the solid, the Se1 P Se2 P Se3 chain of (Cy2P = Se)2Se molecule adopts a syn-anti conformation with the Se1 P Se2 P and P Se2 P Se3 torsion angles of −179.64 (3)° and 4.69 (4)°. The vibrational band assignments, performing at B3LYP/6-311++G (d,p) theory level, are in a good agreement with the experimental FT-IR frequencies. The synthetic utility of the prepared selenide has been exemplified by its reaction with CuCl2 resulted in the formation of [Cu4(Se2PCy2)4] cluster in 53% yield. The structure of latter is formed by a Cu4 tetrahedron, wherein each triangular face is bridged by a [Se2PCy2] ligand in a trimetallic triconnective (μ2, μ1) pattern.

By the method of nanostructure-assisted laser desorption/ionization (NALDI) analysis was performed of solid and liquid fractions of reaction products formed from 2-methylimidazole and 1,3-bis- (iodomethyl)-1,1,3,3-tetramethyldisiloxane. Basing on the data post-source decay of iodides major and minor products of reaction were identified that were registered as ions [M–I]+ and [M–I3]+.

Electron impact mass spectra of alkyl 4-alkoxy-5-amino-3-methylthiophene-2-carboxylates were studied for the first time. These compounds, except for 4-(1-ethoxyethoxy) and 4-(ferrocenylmethoxy) derivatives, give rise to a stable molecular ion whose decomposition follows three pathways. The main fragmentation pathway of the molecular ion is elimination of alkyl radical from the 4-alkoxy group, the second pathway involves expulsion of alkoxy group from the ester moiety, and the third pathway is decomposition of the thiophene ring. The molecular ions of 4-(1-ethoxyethoxy)thiophenes decompose mainly via elimination of ethyl vinyl ether molecule with formation of [M–VinOEt]+ · odd-electron ion, and fragmentation of the latter follows general pathways. In the mass spectra of 4-(ferrocenylmethoxy)thiophenes the most abundant are ferrocenylmethyl ion with m/z 199 (I rel 100%) and fragment ions derived therefrom.

One-pot condensation of dithiooxamide with 4,5-dichloro-1,2-thiazole-3-carbaldehyde and 5-phenyl-1,2-oxazole-3-carbaldehyde, followed by oxidation of intermediate 2,5-dihydro[1,3]thiazolo[5,4-d]-[1,3]thiazoles with selenium dioxide, afforded previously unknown 2,5-bis(4,5-dichloro-1,2-thiazol-3-yl)- and 2,5-bis(5-phenyl-1,2-oxazol-3-yl)[1,3]thiazolo[5,4-d][1,3]thiazoles as first representative of bis-isothiazolyl- and bis-isoxazolyl thiazolothiazoles.

A novel, simple approach to 2-(1-alkoxyprop-1-enyl)-5-ethenylidene-4,5-dihydro-1,3-thiazoles has been disclosed through the reaction of (propargylsulfanyl)-2-aza-1,3,5-trienes (readily available from alkoxyallenes, isothiocyanates, and propargyl bromide) with potassium or sodium tert-butoxide (1.1–1.4 equiv) under mild conditions [DMSO/THF (∼1:4–5), ca. −30 °C, 15–30 min]. The process proceeds through deprotonation of an activated SCH2 group, followed by intramolecular [1,5]-ring-closure. Unlike alkyl-, benzyl-, and allylsulfanyl-analogues, the exclusive or competitive formation of seven-membered azaheterocycles was not observed.

The electron impact mass spectra of 1-R-substituted 3-alkoxy-2-(propargylsulfanyl)- and 3-alkoxy-2-(allenylsulfanyl)-1H-pyrroles (R = Me, i-Pr, s-Bu, Ph) have been studied for the first time. These compounds give rise to stable molecular ions whose primary fragmentation follows three competing pathways: cleavage of the C–O bonds with expulsion of alkyl radical, cleavage of the C–S bonds with formation of [M–C3H3]+ ions, and cleavage of the C–N bonds with synchronous hydrogen transfer to give odd-electron [M–CnH2n]+ · ion. The main fragmentation pathway of 2-(propargylsulfanyl) derivatives is cleavage of the C–S bond with formation of [M–C3H3]+ ion.

By mass spectrometry methods applying electron ionization (70 eV) and laser desorption/ionization (NALDI, MALDI) 1-(alkyl-, cycloalkyl-, vinyloxyethyl-, and aryl)substituted 2-(alkyl- and propargylsulfanyl)-3-(ferrocenylmethoxy)pyrroles were studied and characterized. At the electron ionization the peak of the molecular ion possesses very low intensity. The main fraction ions are the ferrocenylmethyl ion (the most abundant peak) and its decomposition ions. Under the NALDI conditions molecular ions and protonated molecules [M + H]+ are generated. The general fragmentation rules in the field-free region are determined. By an example of 1-phenyl derivative of pyrrole the MALDI procedure was also demonstrated to be suitable for investigation of 2-(alkylsulfanyl)-3-(ferrocenylmethoxy)pyrroles.

Secondary phosphine chalcogenides, R2PX (R═(CH2)2Ph, Ph; X = S, Se), react with divinyl chalcogenides, (CH2═CH)2Y (Y = S, Se, Te), at the 2:1 molar ratio (80–82°C, 56–80 h) in the absence of both catalysts (initiators) and solvents to quantitatively afford the corresponding anti-Markovnikov diadducts. Even at the equimolar reactant ratio, the diadducts are the major products, though monoadducts are also formed. When Y = Te, vinylphosphine chalcogenides and metal Te are obtained, thus showing that divinyl telluride behaves as the vinylating agent.

Secondary phosphines, R2PH (R = Ph, PhCH2CH2), react with fullerene C60 under microwave irradiation at 200–270 °C for 1–2 h in the medium of substituted naphthalenes (1-Cl, 1-Me, 1-MeO) or without solvent to afford mono-adducts, HC60PR2, whose air oxidation gives the corresponding phosphine oxides, HC60P(O)R2, in up to 88% yield.

A reaction of organic dichalcogenides R2Y2 (R = Ph, Bn, Pr; Y = S, Se) with 1,4-dichlorobut-2-yne in the system hydrazine hydrate–KOH leads to four principal products: 1,4-bis(organylchalcogenyl)but-2-ynes, 1-organylchalcogenylbut-1-en-3-ynes, 4-organylchalcogenylbut-1-en-3-ynes, and 3(5)-methylpyrazole. The selectivity of the formation of individual products is determined by the ratio of the substrates used and the reaction temperature. A plausible mechanism of chalcogenation considered in the work agrees with the effect of the nature of chalcogene atoms and organic substituents R on stability of intermediates and products. The stabilization of carbanions by α chalcogene-containing groups corresponds to the following order: PhS > PhSe > BnS > BnSe > PrS.

Fragmentation of 2-(prop-1-en-1-yl)-4,5-dihydro-1,3-thiazoles synthesized from alkoxyallenes or propargylbenzene, isothiocyanates, and benzyl, allyl, or propargyl bromide has been studied under electron impact (70 eV) and chemical ionization (with methane as reactant gas). All compounds under electron impact give rise to stable molecular ions whose decomposition involves concurrent dihydrothiazole ring cleavage and elimination of substituents. The fragmentation pattern is largely determined by the nature of the substituent on C5. Chemical ionization of 4,5-dihydro-1,3-thiazole derivatives is typically accompanied by protonation and electrophilic addition with subsequent elimination of nitrile molecule. No substituent effect on the fragmentation pattern under chemical ionization has been revealed. Unlike electron impact and chemical ionization, the most abundant ion in the MALDI mass spectrum of 2-[(Z)-1-butoxyprop-1-en-1-yl]-4,4-dimethyl-5-phenyl-4,5-dihydro-1,3-thiazole is [M — H]+.

New organosilicon ionic liquids and cyclophanes were synthesized in a one stage by the solvent- and base-free reaction of 2-methylimidazole with 1-iodo- or 1,7-diiodo-2,2,6,6-tetramethyl-2,6-disilaheptanes.

2-(Furan-2-yl)- and 2-(thiophen-2-yl)pyrroles are readily ethynylated with acylbromoacetylenes in the solid Al 2 O 3 medium (no solvent, room temperature, 1 h) to afford 5-(furan-2-yl)- and 5-(thiophen-2-yl)-2-acylethynylpyrroles in 39–74% yields. In the case of 2-(furan-2-yl)pyrroles, an alternative ethynylation of the furan ring takes place, the ratio of the furan and pyrrole ring ethynylation products being 1:5–7. No ethynylation of the thiophene ring as well as ethynylation of both heterocycles in a one molecule has been detected. Thus the reactivity of the heterocycles towards the ethynylation system (acylbromoacetylenes/Al 2 O 3 ) falls in the order: pyrrole>furan>thiophene.

Reaction of red phosphorus with acetylene in multiphase superbasic KOH-DMSO system has been studied. The phosphorylation of acetylene results in poly(divinylphosphinic acid).

Fragmentation patterns of 5-methylsulfanyl-1-vinyl-1H-pyrrol-2-amines under electron impact (70 eV) and chemical ionization (methane as reactant gas) were studied for the first time. The electron impact mass spectra of all the examined compounds contained a strong peak of molecular ion which decomposed along four pathways. Two pathways involved cleavage of the C-S bonds with elimination of methyl (major) and MeS radicals (minor), and the two others, decomposition of the pyrrole ring. The chemical ionization mass spectra displayed strong molecular, [M + H]+, and odd-electron [M + H − SMe]+ ion peaks. N,N-Dimethyl-5-methylsulfanyl-4-phenyl-1-vinyl-1H-pyrrol-2-amine under chemical ionization with methane as reactant gas characteristically decomposed with formation of [M − C4H9N]+ as the only fragment ion.

The direction of the reaction of propane-1,3-dichalcogenolates with 2,3-dichloroprop-1-ene in the system hydrazine hydrate-KOH depends not only on the conditions but to a greater extent on the chalcogen nature. Dipotassium propane-1,3-dithiolate and propane-1,3-diselenolate give rise to products of substitution of the chlorine atom on the sp3-carbon atom, which are capable of undergoing further transformations (domino reaction). Dipotassium propane-1,3-ditellurolate promotes elimination of both chlorine atoms with formation of allene.

Propargyloxymethylferrocene has been synthesized by the modified reaction of available N , N -dimethylaminomethylferrocene with propargyl alcohol in the presence of dichloroethane and NaOH, the yield reaching 99.6%. The rapid prototropic isomerization of propargyloxymethylferrocene in the superbase system t -BuOK/DMSO (room temperature, 4 min) leads to previously unknown allenyloxymethylferrocene in 80% yield. Preliminary cationic and radical polymerizations of both monomers have been studied and novel oligomers with the polyene chain and pendant ferrocenyl moieties containing soluble and insoluble fractions have been synthesized in 83–88% total yield. All the oligomers exhibit semiconducting and paramagnetic properties and stable up to 300–340 °C.

Mass spectrometry and quantum chemical studies of the reaction of divinyl telluride with diphenylphosphine sulfide have been carried out. Reaction proceeds under radical initiation (AIBN, 63–68 °С, 2.5 h, THF, reactants molar ratio = 1:1) to afford the anti-Markovnikov monoadduct 1 and diadduct 2 in 67 and 23% yield, respectively. The former easily decomposes to give vinyldiphenylphosphine sulfide 3 (in 63% yield), ethylene and elemental tellurium, the structure of which represents mainly nano-sized powder consisting of agglomerates with average size of 350–450 nm. The comparative analysis of electron ionization mass spectra of compounds 1, 2 and 3 indicates that the presence of tellurium atom in adducts 1 and 2 reduces stability of their molecular ions and hinders the elimination of sulfur atom. Under conditions of chemical ionization of phosphine sulfides 1 and 3, the process of their protonation with CH5+ followed by the elimination of sulfur atom from [НМ]+ ion is dominant. These data are also confirmed by the results of quantum chemical calculations of the most stable protonated structures of phosphine sulfides 1 and 3.

2,3-Dichloro-1-propene reacts with alkane dithiolates in hydrazine hydrate – KOH medium to produce derivatives of dithiin, dithiepin, chloropropenyl, and allenyl sulfides depending on conditions and dithiolate structure. The formation of the heterocyclic products is a result of possible domino reactions, including a substitution of an allylic chlorine atom, dehydrochlorination, and intramolecular heterocyclization.

The reaction of 3,5-dimethyl-4-formylpyrazoles, bearing various substituents at N-1 atom, with propane-1,3-diselenol and 2-hydroxypropane-1,3-diselenol in the presence of ТМSCl proceeds without heating to chemoselectively give hitherto unknown 2-(pyrazol-4-yl)-1,3-diselenane hydrochlorides in high yields. The latter are easily transformed to the corresponding free bases—2-(pyrazol-4-yl)-1,3-diselenanes. The 15N chemical shifts of the pyrazole ring in 2-(pyrazol-4-yl)-1,3-diselenanes obtained by 2D HMBC-gp (15N-1H) technique are indicative of the N-2 atom protonation in hydrochlorides.

Dimethyldiselenide reacts with 2,3-dichloro-1-propene at 20–25°C in the hydrazine hydrate-KOH medium to form 2-chloro-3-methylselanyl-1-propene with 90% yield. Diphenyldiselenide in the reaction with 2,3-dichloro-1-propene, depending on the conditions, can give quite selectively four products: 2-chloro-3-phenylselanyl-1-propene, phenylselanylpropadiene, 1-phenylselanyl-1-propyne, and Z-1,2-bis(phenylselanyl)-1-propene. The effect of the selenium atom on the reaction direction and the products structure is discussed.

2,3-Dichloroprop-1-ene reacted with diphenyl disulfide in the system hydrazine hydrate-potassium hydroxide at 30–35°C to give three products: 2-chloro-3-phenylsulfanylprop-1-ene, 1-phenylsulfanylpropadiene, and 1-phenylsulfanylprop-1-yne. Variation of temperature ensures selective synthesis of one of the above products, which confirms their successive formation (domino reaction). The domino reaction at 60°C goes further to afford (Z)-1,2-bis(phenylsulfanyl)prop-1-ene.

Fragmentation patterns of the molecular ions of 5-(methylsulfanyl)-1-[2-(vinyloxy)ethyl]-1H-pyrrol- 2-amines generated by electron impact (70 eV) and chemical ionization (methane as reagent gas) were studied for the first time. The electron impact mass spectra of all the examined compounds showed abundant molecular ions whose subsequent fragmentation followed three main pathways: elimination of EtS radical, elimination of methyl radical from the MeS group, and cleavage of the C-N and/or C-C bonds which is accompanied by rearrangement processes. Further decomposition of the [M - EtS]+ ion is determined by the structure of the amino group. The chemical ionization mass spectra displayed strong molecular and [M + H]+ ion peaks together with representative series of fragment ion peaks. Unlike electron impact, the main decomposition pathway under chemical ionization is elimination of methylsulfanyl radical from the [M + H]+ ion to give abundant [M + H — MeS]+ ion.

2-Chloro-1-propen-3-yl isothiuronium chloride reacts with potassium ditelluride in hydrazine hydrate to afford elemental tellurium and allene. The latter is formed due to the vicinal elimination of chlorine and a sulfur-bearing moiety.

Thioacetalization of the nitrobenzaldehydes with 2-mercaptoethanol is easily carried out in the presence of TMSCl and dichlorodimethylsilane without heating and using of additional solvent. The reaction direction is defined by the reagents ratio and led to formation of bis(2hydroxyethyl)dithioacetals (yield 76-91%) or 1,3-oxathiolanes (yield 76-91%). Bis(2-hydroxyethyl)dithioacetals are easily transformed in the corresponding 1,3oxathiolanes at long storage without heating or influence of catalysts, and also under electronic and chemical ionization.

The results of the synthesis of tellurium-containing oligomers based on 1-bromo-2-methyl-3-chloropropane are presented. By the example of the reductive splitting of tellurocol the possibility is demonstrated of the synthesis of methyltellanyl derivatives, which are valuable reagents for organic synthesis and for the design of coordination compounds.

trans,trans -1,4-Diphenylbuta-1,3-diene reacts with elemental (red) phosphorus in the superbasic KOH / DMSO (H 2 O) system (120 °C, 3 h) to give, after acidic work-up, 1,4-diphenylbutylphosphinic acid in 48% yield.

The mass spectra of 1-substituted 3,5-dimethyl-1H-pyrazole-4-carbaldehyde bis(2-hydroxyethyl) dithioacetals and thioacetals were studied for the first time. The main fragmentation pathways of their molecular ions generated under electron impact and chemical ionization were similar. Primary decomposition of the molecular ions of bis(2-hydroxyethyl) dithioacetals involves elimination of 2-sulfanylethanol molecule with formation of the corresponding 1,3-oxathiolane radical cation. Fragmentation of the molecular ions [M]+ · and [M + H]+ derived from 2-(3,5-dimethyl-1H-pyrazol-4-yl)-1,4,6-oxadithiocanes includes cleavage of the eight-membered heteroring and elimination of C4H9OS ·. Substituents in the heteroring of pyrazolecarbaldehydes inhibit decomposition processes related to the aldehyde group.

The three-component reaction between isoquinoline, 1,3-diphenylprop-2-yn-1-one and nitromethane (90–100°C, 26h) affords 2,4-diphenyl- pyrido[2,1-a]isoquinolinium nitrite in 23% yield along with oligomers.

The mass spectra of previously unknown 1-alkyl(cycloalkyl, aryl)-3-alkoxy(aryl)-2-methylsulfanyl-1H-pyrroles were studied. Fragmentation of all 3-alkoxy-substituted pyrroles under electron impact (70 eV) follow both ether and sulfide decomposition paths; In particular, 1-R-substituted 3-methoxy-2-methylsulfanyl-1H-pyrroles (R = Me, Et, i-Pr, s-Bu, cyclo-C5H9, cyclo-C6H11, Ph) lose methyl radical group from both methoxy and methylsulfanyl groups. The mass spectra of 1-sec-butyl- and 1-cycloalkylpyrroles also contained a strong peak (10–49%) from odd-electron [M — C n H2n ]+· ion formed via cleavage of the N-R bond with synchronous hydrogen transfer. Cleavage of the O-Alk bond in the fragmentation of 3-alkoxy-1-isopropyl-2-methylsulfanyl-1H-pyrroles (Alk = Et, i-Pr, t-Bu) was accompanied by rearrangement process leading to the corresponding alkene and odd-electron 1-isopropyl-2-methylsulfanyl-1H-pyrrol-3-ol ion. The main fragmentation path of 1-alkyl-2-methylsulfanyl-3-phenyl-1H-pyrroles (Alk = Me, i-Pr) under electron impact involves dissociation of the S-Me bond with formation of rearrangement 1H-[1]benzothieno[2,3-b]pyrrol-8-ium ion.

Using as example 3-methoxy-1-(2-methoxyethyl)-2-methylsulfanylpyrrole, obtained in one preparative stage from α-lithiated methoxyallene and 2-methoxyethyl isothiocyanate, a facile cleavage of a C–O bond in the N-(2-methoxyethyl) substituent by the t-BuOK–DMSO system has been discovered, opening access to a new class of N-vinylpyrroles (through β-elimination of methanol).

Mass spectra were investigated for the first time of four structural isomers of heterocycles, formerly inavailable 7-methyl-2-(methylsulfanyl)-3-(1-ethoxyethoxy)-4,5-dihydro-3H-azepine, 2,2-dimethyl-6-(methylsulfanyl)-5-(1-ethoxyethoxy)-2,3-dihydropyridine, 1-isopropyl-2-(methylsulfanyl)-3-(1-ethoxyethoxy)pyrrole, and N-isopropyl-N-methyl-3-(1-ethoxyethoxy)-2-thiophenamine prepared from a single linear precursor, adduct of α-lithiated 1-(1-ethoxyethoxy)allene and isopropyl isothiocyanate. All compounds formed a molecular ion (Irel 1–6%) whose primary fragmentation at the electron impact (70 eV) occurs in two principal directions related to the cleavage of the C-O bonds in the 1-ethoxyethoxy-substituent: with a simple rupture of the bonds C-OEt and C-O(heterocycle) and with the elimination of an ethoxyethene molecule. In the spectra of 4,5-dihydro-3H-azepine and 2,3-dihydropyridine the first fragmentation channel of [M]+· dominates. The second direction prevailes at the fragmentation of pyrrole and thiophene molecular ions leading to an odd-electrons ion with m/z 171. Further fragmentation of this ion is characteristic of each isomer and resulted in the formation of diagnostic ions providing a possibility of identification of these isomers by mass spectrometry.

Tellurium reacts with dichloromethane in the system hydrazine hydrate-alkali substituting one chlorine atom by tellurium whereas the second chlorine atom undergoes reductive substitution by hydrogen leading to the formation of methyltellanyl derivatives. Tentative mechanism of reduction is discussed. The discovered reaction allows the preparation of organotellurium compounds containing the MeTe group, including those involving other chalcogens.

5-(2-Thienylsulfanyl)thiophene-2-carbaldehyde reacted with propane-1-thiol and propane-1,3-dithiol in the presence of chloro(trimethyl)silane to give previously unknown 5-[bis(propylsulfanyl)methyl]-2-(2-thienylsulfanyl)thiophene and 2-[5-(2-thienylsulfanyl)thiophen-2-yl]-1,3-dithiane. Chloromethylation of 5-(2-thienylsulfanyl)thiophene-2-carbaldehyde with formaldehyde in a stream of hydrogen chloride in the presence of zinc chloride resulted in the formation of an oligomeric product consisting of thiophene rings connected alternately by sulfur and methylene bridges. The oligomer is formed via fast polycondensation of the primary chloromethylation product with the initial aldehyde. 5-(2-Thienylsulfanyl)thiophene-2-carbaldehyde was oxidized at the sulfide and aldehyde groups with 30% hydrogen peroxide in glacial acetic to produce 5-(2-thienylsulfonyl)thiophene-2-carboxylic acid.

The reaction of 1,1-dichloroethane with tellurium in the system hydrazine hydrate-potassium hydroxide gave ethyltellanyl derivatives as a result of replacement of one chlorine atom in the substrate by tellurium, and of the other, by hydrogen. Probable mechanisms of reduction of the C-Cl bond and mass spectra of the products were considered. The mass spectra of ditelluroacetals revealed unusual rearrangement of the molecular ion, leading to the formation of Te-Te and new C-C bond.

2,3-Dichloro-1-propene reacts with sulfur dissolved in the system hydrazine hydrate-KOH (with formation of K2S2 or K2S) to afford bis(2-chloro-1-propene-3-yl)sulfide as the main product in both cases. Under similar conditions tellurium induces β-elimination of both chlorine atoms resulting in the formation of allene and complete regeneration of tellurium metal.

The electron impact mass spectra of previously unknown 2-alkyl-6-alkoxy-, 2,3-trimethylene-6-alkoxy- and 2-alkyl-6-aryl(hetaryl)-3H-azepines were studied. All compounds give rise to stable molecular ions (Irel = 44–100%) whose fragmentation pattern is determined mainly by the substituent on C6. Decomposition of the molecular ions derived from 6-alkoxy derivatives (R1 = MeO, EtO, i-PrO) follows general relations typical of alkyl ethers. The main characteristic peaks in the mass spectra of 2-methyl-6-aryl- and 2-methyl-6-hetaryl-3H-azepines (R1 = Ph, 1H-pyrrol-1-yl, 5-methylthiophen-2-yl) belong to even-electron rearrangement ions [M − H]+ and [M − Me]+, which have conjugated bi- and tricyclic structures, and products of their subsequent decomposition. Substituents in positions 2 (R2) and 3 (R4) [R4 = H, R2 = Me, Et; R2R4 = (CH2)3] bring some specificity to the fragmentation pattern, but their contribution is not crucial.