REACTIONS OF SULFUR DIOXIDE WITH AMINOPHOSPHINES

Abstract

The reactions of SO₂ with tris-dimethylaminophosphine, bis-dimethylaminofluorophosphine, bis-dimethylaminochlorophosphine, dimethylaminodifluorophosphine, dimethylaminodichlorophosphine, 1,3-dimethyl-2-fluoro-1,3,2-diazaphospholidine and 1,3-dimethyl-2-chloro-1,3,2-diazaphospholidine have been investigated. The complex reactions are dominated by facile oxidation of the respective phosphine to phosphoryl and thiophosphoryl derivatives. The new heterocyclic phosphines CH₃ NCH₂CH₂N(CH₃)P(O)F and CH₃ NCH₂CH₂N(CH₃)P(S)F have been isolated and characterized by NMR, infrared, and mass spectrometry.     

REACTIONS OF TELLURIUM TETRAHALIDES WITH GLYCOLS

Abstract

Tellurium tetrahalides undergo reaction with glycols to yield three different products: O,O'-dioxotrihalotellurates; bis(alkoxy)dihalotellurium (IV) compounds and hexahalotellurates. The course of the reaction appears to be determined primarily by the nature of the glycol. The structure of dichlorobis(cis- 2-hydroxycyclohexyloxy)tellurium(IV) has been determined crystallographically     

ELEMENTAL SULFUR REACTIONS WITH 2-PICOLINE

Abstract

A study of the reaction of the elemental sulfur with 2-picoline is reported. The process was carried out at the boiling point of the 2-picoline under argon. After removing unreacted solids, the reaction products were identified by means of LC. GC and GC-MS. The following products have been identified by mass spectrometry: 1,2-di/2-pyridyl/-ethane. 1,2-di/2-pyridyl/-ethene. 2-methyl-x-[/2-pyridyl/methyl]pyridines, 2-mercapto-methyl-[x/2-pyridyl/methyl]-pyridines, l-mercapto-1,2-di/2-pyridyl/-ethane, 5,6-di/2-pyridyl/-5H-cyclopenta-[b]pyridine, 5,6-di/2-pyridyl/-7H-cyclopenta[b]pyridine, 1,2,3-tri/2-pyridyl/-propane. 1,2-di/2-pyridyl/-1-[x-/2-methyl/-pyridyl]-ethane, 5,6-di/2-pyridyl/-7-[/2-pyridyl/methyl]-7H-cyclopenta[b]pyridine, 5,6-di/2-pyridyl/-5-[/2-pyridyl/-methyl]-5H-cyclopenta-[b]pyridine. Di{7-[5,6-di/2-pyridyl/-7H-cyclopenta[b]pyridyl]} sulfide and di(7-[5,6-di/2-pyridyl/-7H-cyclopentalblpyridyl]} disulfide.     

REACTIONS OF XENON DIFLUORIDE WITH ORGANO-SULPHUR MOLECULES

Abstract

Xenon difluoride readily reacts with various organo-sulphur compounds. In general, three types of products were isolated, the course of the reactions depending on the structure of the organo-sulphur substrate. Alkyl-phenyl substituted sulphides, 3,3-dibromothiochroman-4-one and thiochroman-4-ol reacted to form α-fluoro substituted products, 2,5-diphenyltetrahydrothiopyran-4-one, thiochroman-4-one and 3-bromothiochroman-4-one formed dehydrogenated products, while diphenyl-sulphide, dibenzothiophene and 10-thioxanthenone reacted to form sulphoxide and sulphone. The reaction mechanism and the reaction pathways, which are shown on the Scheme, will be discussed.     

REACTIONS OF CHLOROTHIOLFORMATE ESTERS WITH DIMETHYL SULFOXIDE

Abstract

The reaction of an alkyl chloroformate with dimethyl sulfoxide gives the corresponding alkoxysulfonium chloride (I; X = 0) and carbon dioxide. However, the corresponding reactions with chlorothiolformate esters do not yield the salts (I; X = S). Phenyl chlorothiolformate reacts with dimethyl sulfoxide according to equation [1].     

REACTIONS OF 1,3-DIOXACYCLANES WITH SULPHURY COMPOUNDS

Abstract

Saturated 1,3-dioxacyclanes under acid catalysis conditions react with thiods forming thioacetals and glycols. The effect of the type of catalysts, structure of reagents and regime parameters on the direaction and selectivity of the process was studies.     

REACTIONS OF DITHIOLETHIONES WITH N,N-DICHLOROAMIDES

Abstract

Dependent on the starting materials and the reaction conditions N,N-dichloroamides Cl₂N-X (X = COaryl, CO₂alkyl, SO₂aryl, SO₂N(alkyl)₂) react with dithiolethiones 1 and 5 to N-(dithiolyliden)amides 2, 6, S-(dithiolylidene)sulfimides 3, thionoxides 7 and dithiolones 4, 8. The mechanisms have been studied.     

METHYLTHIODITHIOLYLIUM REACTIONS WITH 2-BUTENE NITRILES DERIVATIVES

Abstract

The 3-methylthio-1. 2-dithiolylium including at 5 position a donor substituent, in acetic acid in the presence of pyridine, the 2-methylthio-1. 3-dithiolylium ions in methylene chloride-triethylamine, react with the 2-butene nitrile derivatives and lead to the (A) and (B) corresponding 4-dithiolylidene-2-butene nitriles. In contrast ring opening reaction of the 1, 2-dithiole is observed when 2-cyano-3-phenyl-2-butene nitrile reacts with the 3-methylthio-4-aryl-1. 2-dithiolylium ions in 3 and 5 positions, in methylene chloride-triethylamine. The nucleophilic attack on the 5 position of the dithiolylium ion leads to a 2-cyano-3-phenyl-3 (4-aryl-5-methylthio-2-thienyl) propene nitrile (C), meanwhile the attack on the 3 position leads to a 2-cyano-3-phenyl-3-(4-aryl-3-mercapto-2-thienyl) propene nitrile (D). The proposed structures are established by means of physical methods (IR, NMR, and Mass Spectrometry) and by non ambiguous synthesis. The reactivities of the various sites are explained in function of the electronic and steric effects, furthermore the reaction conditions and the intermediary isolation allow to propose the mecanisms of these reactions.     

CHEMILUMINESCENCE OF SOME REACTIONS WITH MOLECULAR OXYGEN

Abstract— Many inorganic oxidation reactions involving a variety of oxidizing agents show chemiluminescence in the spectral region of 400–600 mp. Excited O₂O₂-associates are assumed to be the emitting molecules formed by bimolecular recombination of HO _x O₂-radicals. Oxidation of sodium sulfite with molecular oxygen in the presence of Cu- and Fe-basic oxides shows chemiluminescence which originates from the reactions of the heavy metal complexes of OH- and O, H-radicals with O₂. The simplest way of producing a radical from O₂ is by the uptake of one electron. Suitable electron donors, such as hydro-quinones and semiquinones, emit light if treated with oxygen. In certain organic solvents OH- can also act as electron donor. Its presence causes the formation of semiquinones from quinones in the absence of oxygen. The chemiluminescence which is observable upon treatment of alkaline dimethylsulfoxide, dioxane, pyridine-water and alcohol-water mixtures with oxygen is also attributable to electron transfer from OH- to O₂.     

金属镓促进的巴豆基溴与醛的反应

α－甲基烯丙基醇是合成一些大环内酯（ｍａｃｒｏｌｉｄｅ），聚醚抗生素（ｐｏｌｙｅｔｈｅｒａｎｔｉｂｉｏｔｉｃｓ）和信息素的重要中间体［１］。立体选择性地合成α－甲基烯丙基醇是当今最富挑战性的课题之一。正是因为这类化合物具有广泛的合成价值，以致于有三十...     

REACTIONS OF OXIDIZED THIOUREAS WITH AMINE NUCLEOPHILES1

Abstract

A route for the convenient, cost effective synthesis of di- and tri-substituted guanidines from thioureas has been developed. The key transformation involves activation of the sulfur through S-oxidation followed by displacement of the activated sulfur by an amine nucleophile (oxidation/displacement). This preparation is experimentally facile and results in good isolated yields of desired guanidines. No noxious substances or sensitive intermediates are generated. The reaction time is short and overall yield of desired guanidine from thiourea is good.     

SINGLET OXYGEN REACTIONS WITH 2,7-DIMETHYL-2,6-OCTADIENE

Abstract— Results concerning Rose Bengal sensitized photoxidation of 2,7-dimethyl-2,6-octadiene (A) are discussed. This diolefin may be considered as a model molecule of polyisoprene of polymerization number two with 1,4-4,1 addition mode.
All the mono- and dihydroperoxides apt to occur are actually obtained. One of the occurring hydroperoxides, 2,7-dimethyl-dihydroperoxy-3,5-octadiene, which has the structure of a conjugated diene, does not lead to an endoperoxide. This is contrary to Kaplan and Kelleher's hypothesis. On the other hand, no trihydroperoxide forms as a result of further addition of singlet oxygen (¹O₂).
A complete kinetic study has allowed us to determine the rate constants of all the reactions which take place. The reactivity of (A) is twice that of 2-methyl-2-pentene and the addition of ¹O₂ to one of the double bonds of (A) induces deactivation of the remaining double bond.     

STUDIES ON CYCLOADDITION REACTIONS OF VINYLPHOSPHONATES WITH NITRONES

Cycloaddition reactions of vinylphosphonates with nitrones were studied. A series of 4-phosphonyl-3-aryl-N-arylisoxazolidines were synthesized by the reaction of vinylphosphonates with nitrones. The structure of 3a was confirmed by X-ray single-crystal diffraction.     

STEREOSELECTIVE REACTIONS OF CHIRAL AMINES WITH RACEMIC CHLOROPHOSPHINES

Racemic chlorophosphines react stereoselectively with chiral l-phenylethylamines or amino acid esters to give diastereomerically enriched aminophosphines 3, which were isolated as diastereomerically pure crystalline borane complexes. Oxidation, thionation, the reaction with methyl iodide provide optically active derivatives of aminophosphines. (R,S)- and (S,S)-stereomers of phosphinic acid amides were separated by crystallization and a flash-chromatography. The stereochemical properties of phosphorus acid amides were investigated. The mechanism of asymmetric induction at the trivalent phosphorus atom was rationalized.     

REACTIONS OF THE SUBSTITUTED THIOUREAS WITH PLATINUM COMPOUNDS

Abstract

Thiourea and its derivatives easily form the complexes with compounds of Cu^II, Fe^III, Pt^IV etc. By the formation of complexes as a rule redoxprocess proceeds to give an appropriate thiourea disulphide. It has been shown, that redoxprocess goes on prejudice on the derivatives of thiourea in that case when the thion-thiol tautomerism is possible.     

含活泼亚甲基多环芳烃与N—溴代丁二酰亚胺的光化学反应

多环芳烃主要来自煤焦油 ,由于这些化合物电子密度高和对称性好 ,在合成耐热性高分子和液晶高分子等聚合物材料方面优于单环芳烃 ,在高性能染料、涂料、医药和农药的合成上也具有良好的应用前景 ,因此探索煤焦油中富含的多环芳烃的转化和利用是提高煤非燃料利用的有效途径。本文利用ＮＢＳ(Ｎ 溴代丁二酰亚胺 )作为光溴化剂 ,研究了温和条件下ＮＢＳ与几种典型的含活泼亚甲基芳烃的光化学反应 ,通过对芴、二苯甲烷 (ＤＰＭ )和二 (1 萘 )甲烷 (ＤＮＭ)等含活泼亚甲基的多环芳烃进行官能团转化 ,得到活泼的溴代中间体 ,为进一步合成多环芳烃…     

REACTIONS OF A PHOSPHORANIMINE ANION WITH SOME ORGANIC ELECTROPHILES

Abstract

The reactions of a variety of electrophiles with the N-silyl-P-trifluoroethoxyphosphoranimine anion Me₃Sin°P(Me)(OCH₂CF₃)CH^? ₂ (1a), prepared by the deprotonation of the dimethyl precursor Me₃SiN[dbnd]P(OCH₂CF₃)Me₂ (1) with n-BuLi in Et₂O at-78°C, were studied. Thus, treatment of 1a with alkyl halides, ethyl chloroformate, or bromine afforded the new N-silylphosphoranimine derivatives Me₃SiN[dbnd]P(Me)(OCH₂CF₃)CH₂R [2: R = Me, 3: R = CH₂Ph, 4: R = CH[sbnd]CH₂, 5: R = C(O)OEt, and 6: R = Br]. In another series, when 1a was allowed to react with various carbonyl compounds, 1,2-addition of the anion to the carbonyl group was observed. Quenching with Me₃SiCl gave the O-silylated products Me₃SiN[dbnd]P(Me)(OCH₂CF₃)CH₂°C(OSiMe₃)R¹R² [7: R ¹ = R ² = Me; 8: R ¹ = Me, R ² = Ph; 9: R¹ = Me, R ² = CH[sbnd]CH₂; and 10: R ¹ = H, R ² = Ph]. Compounds 2–10 were obtained as distillable, thermally stable liquids and were characterized by NMR spectroscopy (¹H, ¹³C, and ³¹P) and elemental analysis.     

REACTIONS OF PHOSPHORUS MONOTHIO ACIDS WITH ALIPHATIC DIAZO COMPOUNDS

Abstract

Reactions of phosphorus monothio acids with diazomethane, diazoacetone, diphenyldiazomethane, and diazofluorene have been studied. The ratio of the yields of the S- and O-derivatives Q_S/Q_O has been found to be dependent on three factors: i) the nature of substituents at phosphorus - with electron-donor substituents raising the O-derivative yield and the quantity log (Q_S/Q_O) varying as εσ of the substituents; (ii) stability of alkyldiazonium and carbocation - with Q_O increasing with the carbocation stability; and (iii) polarity of the medium - the O-derivative yield rises with dielectric permeability of the medium and Q_S/Q_O has been found to be a linear function of 1/D. The most probable mechanism has been established as proton transfer from the acid to the diazocompound followed be formation of the S-derivative and the O-derivative. The former results from an S_N2 reaction of the alkyldiazonium cation with the thiol-thione anion within the ion pair. The O-derivative arises from the thiol-thion anion and the carbocation; the latter resulting from decomposition of the alkyldiazonium cation within the ion pair.