Methylthio Compounds Research Articles

Theoretically optimized geometry based qualitative explanations for the 1H NMR and voltammetry behaviors of [Mg(OBTTAP)

PM3 and DFT calculations have been used to obtain fully optimized geometries of [Mg(OBTTAP)] (where, OBTTAP = octakis(benzylthiotetraazaporphyrin)). Both methods gave Mg-TAP structural features that are in agreement with the crystallographic data on analogous methylthio compounds. The position of the –S–CH 2C 6H 5 vis-à-vis the M-TAP core in the PM3 optimized geometry was used to qualitatively explain 1H NMR signals and the electro-oxidation behavior of complex in cyclic voltammetry.

Crystal and Molecular Structures of Methoxy and Methylthio Compounds

Abstract The six crystal structures of XCH2OCH3 (X = CN, Cl, OCH3) and XCH2SCH3 (X = CN, CH3, SCH3), which are liquid at room temperature and atmospheric pressure, have been determined by X-rays. The crystals belong to the monoclinic system and the space groups are P21/c or P21/n. The molecules in all the crystals have the gauche conformations, which is consistent with the most populated conformation in the liquid and gaseous state estimated by IR spectra and the most stable conformations obtained by ab initio molecular orbital calculations. Such a gauche conformation is probably caused by the anomeric effect in the X–C–O–C or X–C–S–C chains. In all the crystals two molecules are coupled by two antiparallel C–H···O or C–H···S hydrogen bonds to form a four-membered ring. Such a dimer-like pair may be strengthened by the intermolecular interaction between the C–O or C–S bond moments in the four-membered ring.

Darstellung und Reaktionen von 2-Mercapto-6-thioxo-thiopyran-3-carbons�ure-Derivaten

Synthesis and Reactions of 2-Mercapto-6-thioxo-thiopyran-3-carboxylate derivatives 6-Amino-thiopyran-2-thiones (1) react with dihydrogen sulfide in the presence of pyridine and triethyl amine to yield 6-thioxo-thiopyran-2-thiolates (2). Methylation of 2 gives the methylthio compounds 3 and 4. Further methylation of 3a and 4a yields the thiapyrylium salt (7). The reaction of 2-imino-thiopyran (6) with carbon disulfide represents another route to the 6-methylthio-thiopyran-2-thione (4a). The 2-methylthio-thiopyran-6-thione (3a) undergoes substitution of the methylthio group with amines to 8 or reacts with phenylhydrazine to phenylhydrazono-thiopyrane (9c). 6-Thioxo-thiophen-2-thiolates (2a,b) react with hydrazine hydrate to give hydrazono-thiopyranes (10a,b) which can be S-methylated. On the contrary 2c gives with hydrazine hydrate under ring transformation the pyridine-2-thiolate (11). N,S-Acetals (12) and 1,3,4-thiadiazoles (15), which give rise to new pyridine derivatives (14) and (17), can be obtained from 1-Amino-pyridin-2-thiolate (11).

Facile Preparation and Charge-Transfer Complexes of Naphtho[1,8-bc:4,5-b′c′]dithiophene and 2,5-Dimethyl and Bis(methylthio) Derivatives

Abstract Naphtho[1,8-bc:4,5-b′c′]dithiophene was conveniently prepared via annulation of benzo[1,2-b:4,3-b′]dithiophene and converted to 2,5-dimethyl and bis(methylthio) derivatives. The parent and methylthio compounds have a herringbone type of crystal structures, and formed conductive charge-transfer complexes with iodine and with DDQ.

Radical Analysis in the Pyrolysis of Hydrocarbons by Scavenging with Dimethyl Disulfide

AbstractRadicals formed in the low pressure pyrolysis of hydrocarbons can be quantitatively analyzed by scavenging them with dimethyl disulfide (DMDS) in the condensed phase, the pyrolyses of several hydrocarbons (ethyne, ethene, 1.3‐butadiene, and benzene) have been studied in a flow reactor at 1300 K and 10.7 mbar. Samples of the hot gas mixture leaving the reactor were taken continuously by a quartz probe, the resulting supersonic nozzle beam was frozen together with an excess of DMDS on the inner surface of two hollow hemispheres cooled by liquid nitrogen. While melting the scavenging reaction takes place. The mixture of DMDS, stable pyrolysis products, and methylthio compounds was separated and identified with a GC‐MS‐system. CH*3, C2H*3, C6H*5 radicals and H‐atoms have been detected. The presence of acetone in ethyne pyrolysis has an important influence on the radical concentrations and the product yields.

Radicals in flames: Analysis via scavenging reaction

Radicals in flames can be quantitatively analyzed by condensing flame gases along with a radical scavenger. Gas phase samples were taken from fuel-rich and sooting premixed low-pressure flames (27 mbar) by a nozzle beam. They were frozen simultaneously with an excess of dimethyl disulfide (DMDS) at liquid nitrogen temperature. High condensing efficiencies were achieved when both sample and scavenger alike had condensed on the inner surface of a hollow sphere. The scavenging reaction between a radical and the DMDS had taken place in the condensed phase and yielded a stable methylthio compound. The products were separated and identified by using the GC/MS-technique. This novel method was applied to ethyne/oxygen (=2.50) and benzene/oxygen (=1.80_ flames. Aside from the stable condensable flame products, such as polyynes and aromatic hydrocarbons, mono- and poly-methylthio compounds could be analyzed depending on the number of radical sites per molecule. Among the scavenged radicals aromatic radicals like phenyl, benzyl, indenyl, naphthyl, and the phenoxy radical, as well as a number of aliphatic radicals, including ethynyl, C 2 , C 3 H, and the carbenes CH 2 , C 3 H 2 , and C 5 H 2 , could be detected. Concentration profiles of radicals in both flames are reported and subsequently discussed. Conclusions are drawn concerning the polyynes, the formation of aromatic structures by the combustion of aliphatic fuels, and the reactions of aromatic compounds in sooting flames.

Heterocyclische Siebenring‐Verbindungen, XXXVI. Synthese und Eigenschaften des 1,4‐Benzoxazepins und einiger monosubstituierter Derivate

Heterocyclic Seven‐Membered Ring Compounds, XXXVI. — Synthesis and Properties of 1,4‐Benzoxazepine and of Some Monosubstituted DerivativesO‐Alkylation of salicylamide with bromoacetaldehyde diethyl acetal and subsequent thermal ring closure yields the lactam 2, which is converted into the imide chloride 3. Pd(0)‐catalyzed dehalogenation of compound 3 with tributyltin hydride leads to the desired 1,4‐benzoxazepine (4), a thermally very unstable compound which prefers polymerization to valence isomerization. O‐Alkylation of the lactam 2 and S‐alkylation of the thiolactam 8 yield the 5‐substituted 1,4‐benzoxazepines 6 and 9, resp., which are thermally considerably more stable than the parent compound 4. Thus, they are capable of the expected thermal isomerization to the corresponding hydroxyisoquinolines 10 and 11, resp. The photoisomerization of the 1,4‐benzoxazepines 4, 6, and 9 leads to the thermally very unstable dihydroazetes 12, 13, and 14, of which only the methylthio compound 14 could be isolated as crystalline compound.

ChemInform Abstract: Studies on the Chemistry of O,N‐ and S,N‐Containing Heterocycles. Part 3. Synthesis of 1,5‐Benzothiazepines with Potential CNS Activity.

AbstractThe benzothiazepinethiones (II), prepared from the corresponding lactams (I), are methylated to give the methylthio compounds (IV) which undergo substitution reaction with the hydrazides (V), yielding the acyl hydrazines (VI).

Occurrence of isopropylthio compounds in the aquatic ecosystem (Lake Neusiedl, Austria) as a chemical marker for Microcystis flos-aquae

Volatile organic sulfur compounds occuring during a bloom of different species of Microcystis in Lake Neusiedl, Austria, were analyzed by gas chromatography and mass spectrometry. In open water diisopropyl disulfide and diisopropyl tri-sulfide were the only sulphur compounds to be found. It was shown that Microcystis flos-aquae was the causative agent for the generation of these sulphur compounds, since high concentrations of these substances were found both in the floating scum of cyanobacteria taken from open lake and in axenic cultures of five isolated strains of M. flos-aquae. Strains isolated from colonies of Microcystis aeruginosa were not able to synthesize isopropylthio compounds. Alternatively, methylthio compounds were released. The rather unusual formation of the isopropylthio group can be used as a chemical marker to differentiate between M. flos-aquae and M. aeruginosa as two separate species which hitherto have been regarded as formae. In a canal passing through the reed belt of Lake Neusiedl where Microcystis was missing, these compounds were not detected. Different sulfur compounds (dimethyl disulfide, dimethyl trisulfide, dibutyl sulfide and bis(methylthio) methane) which in part have not yet been reported for freshwater ecosystems occurred at this site. Their origin, however, remains obscure.

SYNTHESIS AND ELECTRONIC STRUCTURE OF POTENTIALLY VALENCE ISOMERIC 1,2-DITHIOLYLIUM-4-OLATES

Abstract Methylthio substituted 1,2-dithiolylium-4-olates 1 are obtained by thiolation of 1,3-dichlorpro pane-2-one or pyruvic thiomorpholide with sulfur and triethylamine in dimethylformamide and subsequent alklyation. Aminolysis yields the amino substituted derivatives. IR and UV/VIS spectra of the bis(methylthio), methylthio dimethylaminophenyl and bis(dimethylaminophenyl) compounds provide evidence in favour of the cyclic structure 1 whereas the spectra of the bis(amino) and amino methylthio compounds are rather compatible with non-cyclic valence isomeric structures 2. Both 1 and 2 react with acids to form 4-hydroxy-1,2-dithiolylium salts. The colour-structure relationships of 1,2-dithiolylium-4-olates were examined by PPP-type calculations. The lowest excited states and the colour determining transitions are accounted for in terms of the dithiolylium and olate moieties. The negative solvatochromism of the colour bands of 1 is related to the marked amount of oxygen-to dithiolylium charge transfer of t...

5-Methylthioribose. Its effects and function in mammalian cells.

The growth responses of 5-deoxy-5-methylthioribose on a 5'-deoxy-5'-methylthioadenosine phosphorylase containing cell line (BW5147) and the methylthioadenosine phosphorylase-deficient cell line (L1210D) were examined. Methylthioribose was shown to dramatically affect these cells, increasing their growth rate, saturation density, and viability. It was also found that methylthioribose could satisfy the methylthio dependence of the enzyme-deficient cell line, L1210D. A model is proposed to explain the selective growth of methylthioadenosine phosphorylase-deficient cells in medium lacking a methylthio donor but containing fetal calf serum. It is hypothesized that cellularly exported methylthioadenosine is degraded to methylthioribose in the presence of medium containing serum of high methylthioadenosine phosphorylase activity (i.e. fetal calf serum). The resultant methylthioribose can then be used to satisfy the methylthio requirement of these cells. To test this theory, various purified preparations of bovine liver methylthioadenosine phosphorylase were used to artificially increase the specific activity of methylthioadenosine phosphorylase in horse serum. In each case, it was demonstrated that only medium containing serum of enzyme activity nearly equal to that of the glutathione-stimulated fetal calf serum activity, supported the growth of methylthio-dependent cells in the absence of methylthio compounds. The data suggest that the degradation of methylthioadenosine and subsequent formation of methylthioribose represents an essential process in the growth of mammalian cells.

S-Propenylcysteine Sulfoxide in Exudates of Onion Roots and Its Possible Decompartmentalization in Root Cells by Bacteria into Attractant of the Onion Maggot, Hylemya antiqua (Diptera : Anthomyiidae)

The contents of S-propenylcysteine sulfoxide (PCSO) in roots and exudates of aseptic onion seedlings, and the total root bacteria counts in septic seedlings were all higher in cultivars that are susceptible to the onion maggot, Hylemya antiqua MEIGEN, than in the resistant ones. In addition, more propylthio oviposition attractants were generated in the susceptible cultivars. In aseptic soil where bacterial metabolism was impossible, PCSO accumulated.In vitro metabolism of the PCSO extract of onion by bacteria produced more methylthio compounds than propylthio compounds, which was in contrast to allinase metabolism in chopped onions. Since intact septic onion seedlings generated these compounds in intermediate proportions, it is suggested that both bacterial metabolism of exudates in soil and activation of alliinase by bacterial decompartmentalization are simultaneously taking place in the onion rhizosphere.

2- 14C-1 -Allyl-3,5-diethyl-6-chlorouracil II: Isolation and Structures of the Major Sulfur-Free and Three Minor Sulfur-Containing Metabolites and Mechanism of Biotransformation

The metabolites of 1-allyl-3,5-diethyl-6-chlorouracil in rabbit urine were isolated by preparative thick-layer, liquid-column, and gas chromatography. With the aid of mass and lH-NMR spectra, and by comparison with an authentic sample, the major metabolite, 1, was identified as 6,8-diethyl-2-hydroxymethyl-tetrahydrooxazolo-[3,2-c]- pyrimidine-5,7(4H,6H)-dione, Metabolite 2 as l-allyl-3-ethyl-5-(l- hydroxyethyl)-6-methylthiouracil, Metabolite 3 as l-allyl-3,5-diethyl- 6-methylthiouracil, and Metabolite 4 as 6,8-diethyl-2-hydroxymethyl- tetrahydrothiazolo-[3,2-c]pyrimidine-5,7(4H,6H)-dione. The mechanism of the formation of sulfur-containing metabolites is discussed, and a new metabolic pathway for the formation of methylthio compounds is proposed.

ChemInform Abstract: IMIDAZOPTERIDINES. II. SYNTHESIS OF IMIDAZO(1,2‐C)PTERIDINES WITH A FUNCTIONAL GROUP AT THE 6‐POSITION

Several imidazo[1,2-c]pteridines with a functional group such as amino, alkylamino, alkoxyl, or hydroxyl group at the 6-position were synthesized by a nucleophilic replacement of 6-methylthioimidazo[1,2-c]pteridine with an appropriate nucleophile. The key intermediate methylthio compound was synthesized by condensation of 4-amino-2-methylthiopteridine with chloroacetaldehyde. Similarly, 4-amino-6,7-dimethyl-2-methylthiopteridine and chloroacetaldehyde gave 2,3-dimethyl-6-methylthioimidazo[1,2-c]pteridine, which was also used as a precursor to synthesize several imidazopteridines analogous to above.

Imidazopteridines. II. Synthesis of Imidazo[1,2-c]pteridines with a Functional Group at the 6-Position

Abstract Several imidazo[1,2-c]pteridines with a functional group such as amino, alkylamino, alkoxyl, or hydroxyl group at the 6-position were synthesized by a nucleophilic replacement of 6-methylthioimidazo[1,2-c]pteridine with an appropriate nucleophile. The key intermediate methylthio compound was synthesized by condensation of 4-amino-2-methylthiopteridine with chloroacetaldehyde. Similarly, 4-amino-6,7-dimethyl-2-methylthiopteridine and chloroacetaldehyde gave 2,3-dimethyl-6-methylthioimidazo[1,2-c]pteridine, which was also used as a precursor to synthesize several imidazopteridines analogous to above.

Alkylthiolation. Evidence for involvement in cell division

Several malignant hematopoietic cells from mice, previously shown to require sulfhydryl compounds and serum for proliferation in vitro , are shown to grow well in medium lacking both of these components if methylthio compounds are provided at appropriate concentrations. The methylthio groups can be provided as the mixed disulfides of methyl mercaptan and various thiols. The optimal concentration of the various disulfides is between 1×10 −5 and 1×10 −4 M. The cells can be maintained indefinitely in serum-free medium containing cysteine-methyl disulfide and one of several purified proteins. The evidence is consistent with the theory that these cells require an exogenous source of alkylthio groups for division, that serum is a source of these groups, and that sulfhydryl compounds act as carriers to transport the groups into the cells. A new diffusion analysis is described for quantitative measurement of disulfides of volatile mercaptans.

Cytokinins: Synthesis of 2-, 8-, and 2,8-substituted 6-(3-methyl-2-butenylamino)purines and their relative activities in promoting cell growth

We have synthesized 2- and 8-monosubstituted and 2,8-disubstituted derivatives of the cytokinin 6-(3-methyl-2-butenylamino)purine ( N 6-isopentenyladenine) and have shown the dependence of growth-promoting activity in the tobacco bioassay upon the position, number, and type of substituent. The representative substituent groups were MeS, Me, MeSO 2, C 6H 5CH 2S, HS and Cl. The 8-methyl derivative was exceptional in being more active than the unsubstituted parent compound. In general, substitution in the 8-position decreases activity less than substitution in the 2-position, with the exception of the electron-attracting methylsulfonyl. Substitution in both the 2- and 8-positions lowers the activity more than substitution at either single position on the adenine nucleus, with the exception of the 2,8-dimethyl derivative. The chloro and methylthio derivatives show activity in the same range as the methyl derivatives, and the mercapto compounds, which exist mainly as CS tautomers, show somewhat less activity than the corresponding methylthio compounds. Bulky (C 6H 5CH 2S and MeSO 2) and strongly electron-attracting (MeSO 2) substituents cause relatively great reduction in cytokinin activity.

Rearrangements in the electron‐impact induced fragmentation reactions of 5‐alkylthio‐1,3,4‐thiadiazolyl‐2‐amines

AbstractThe low resolution mass spectra of a number of homologous 5‐alkylthio‐1,3,4‐thiadiazolyl‐2‐amines have been determined. With the methylthio compound the only significant loss from the molecular ion is the sulphydryl radical. As the homologous series is ascended this reaction becomes less important and is insignificant with the butylthio isomers. The ethylthio compound suffers extensive loss of ethylene and when the alkyl group contains three or more carbon atoms the main reaction is always loss of the olefin coresponding to the alkyl group.All of the n‐alkylthio compounds showed in addition loss of methylthio radical from the molecular ion. A mechanism is proposed and comparisons made with alkyl phenyl thioethers and alkylthio substituted heterocycles.

BIOCHEMICAL STUDIES OF TOXIC AGENTS. THE METABOLISM OF IODOMETHANE

1. The metabolism of iodomethane has been studied after the administration of the compound to rats by subcutaneous injection. 2. The urinary excretion of S-methylcysteine, methylmercapturic acid, methylthioacetic acid and N-(methylthioacetyl)glycine has been demonstrated by paper chromatography. 3. Methylmercapturic acid and N-(methylthioacetyl)glycine have been isolated from the urine of the dosed animals. 4. The methylthio compounds detected represented about 2% of the iodomethane administered.