Action Of Halogens Research Articles

Regio- and stereo-selective halogen-induced cyclization of terminal alkynyl thioethers of 3-phenylquinazoline-4-one

The present work reports the results of the study of the electrophilic heterocyclization of terminal alkynyl thioethers of quinazoline-4-one under the action of halogens. Starting 2-(but-3-in-1-ylthio)-3-phenylquinazolin-4(3H)-one and 2-(pent-4-in-1-ylthio)-3-phenylquinazolin-4(3H)-one were prepared by alkylation of 2-thioxoquinazolin-4-one with butynyl and pentynyl bromide in an alcoholic-alkaline medium, respectively. It was determined that the interaction of 2-(but-3-in-1-ylthio)-3-phenylquinazoline-4(3H)-one with bromine, iodine and iodine bromide is regio- and stereo-selective and leads to the formation of 1-(halogenomethylidene)-6-oxo-5-phenyl-2,3,5,6-tetrahydro-1H-[1,3]thiazino[3,2-a]quinazolinium halides of angular structure as E-isomers. On the contrary, the halogen-induced heterocyclization of 2-(pent-4-in-1-ylthio)-3-phenylquinazolin-4(3H)-one leads to the annelation of thiazepine cycle to quinazoline core with formation of E-1-(bromomethylidene)-7-oxo-6-phenyl-1,2,3,4,6,7-hexahydro-[1,3]thiazepino[3,2-a]quinazolinium tribromide and E-1-(iodomethylidene)-7-oxo-6-phenyl-1,2,3,4,6,7-hexahydro-[1,3]thiazepino[3,2-a]quinazolinium monobromide. It was found that an increase in the carbon length of the terminal alkynyl substituent by one methylene group affects the regioselectivity of the halocyclization process, but does not affect the stereoselectivity.

Highly efficient synthesis and NMR features of novel fused pyrimidothiazinium trihalogenides

AbstractCondensed pyrimidines are a popular class of heterocyclic compounds because they have a wide range of biological activity. This article aims to evaluate the simple, catalyst‐free procedure of synthesis of novel fused pyrimidothiazines. An efficient access to a series of pyrazolo[4′,3′:5,6]pyrimido[2,1‐b][1,3]thiazinium, pyrazolo[3′,4′:5,6]pyrimido[2,1‐b][1,3]‐thiazinium, and benzo[b]thieno[4′,3′:5,6]pyrimido[2,1‐b][1,3]thiazinium trihalogenides was developed via electrophilic heterocyclization of corresponding pyrimidine cinnamyl thioethers under the action of halogens. The XDR and complex NMR investigations were used for solving of final products structure; the anisochronism was observed in the NMR spectra of synthesized compounds for the pairs of ortho‐ and meta‐protons, as well as the N‐phenyl substituents associated with them.

Heterocyclization of 2-(Propargylsulfanyl)-1,3-thiazole Derivatives by the Action of Halogens

Reactions of 2-(propargylsulfanyl)-5-methyl-1,3,4-thiadiazole, N-[5-(propargylsulfanyl)-1,3,4-thiadiazol- 2-yl]benzamide, 2-(propargylsulfanyl)-1,3-benzothiazole, and 2-(propargylsulfanyl)-4,5-dihydro-1,3- thiazole with iodine involved annulation of the unsaturated substituent with formation of fused thiazole ring. 2(5)-(Propargylsulfanyl)-1,3,4-thiadiazole derivatives reacted with bromine to give mixtures of heterocyclization products and bromine adducts to the triple bond. The bromination of 2-(propargylsulfanyl)-4,5-dihydro- 1,3-thiazole afforded only the bromine addition product to the triple bond.

ChemInform Abstract: Electrophilic Heterocyclization of 4,5‐Disubstituted 3‐Allylthio‐4H‐1,2,4‐triazoles by the Action of Halogens.

AbstractElectrophilic heterocyclization of 3‐allylthiotriazoles (I) by action of bromine or iodine results in the regioselective formation of thiazolotriazolium salts [cf.

Electrophilic heterocyclization of 4,5-disubstituted 3-allylthio-4H-1,2,4-triazoles by the action of halogens

A study was carried out on the regioselectivity of the electrophilic heterocyclization of 4,5-disubstituted 3-allylthio-4H-1,2,4-triazoles by the action of bromine and iodine. Factors affecting the halogenation regioselectivity, namely, the nature of the electrophilic reagent and the presence of lithium perchlorate, were studied. A method was developed to obtain 5,6-dihydro-3H-[1,3]thiazolo[3,2-b]triazolium salts. The structure of these salts was confirmed by spectral methods and chemical transformations.

Orthoamide. LIV [1] Beiträge zur Chemie azavinyloger Orthoamid-Derivate der Ameisensäure

Orthoamides. LIV. Contributions to the Chemistry of Azavinylogous Orthoformic Acid Amide Derivatives The azavinylogous aminalester 3 reacts with primary amines to give amidines 5 and 6. In the reaction of 3 with aniline the azavinylogous amidine 7 is produced additionally to the amidine 5c. Ethylendiamine is formylated at both aminogroups, the bis-amidine 8 thus formed is transformed to the salts 9a,b. Benzoxazole and benzimidazole can be prepared from 3 and o-aminophenol and o-phenylenediamine, resp. carboxylic acid amides, urea, thiourea, aromatic acid hydrazides 17 and the sulfonylhydrazide 19 are formylated by 3 at nitrogen to give N-acylated formamidines 14, 16, 18, 20. From 3 and aliphatic acid hydrazides 17 and alkylhydrazines, resp., can be obtained 1,2,4-triazole 21 and 1-alkyl-1,2,4-triazoles 22a,b, resp. N,N-dimethylcyanacetamide (32) reacts with 3 and the orthoamide 4a, resp., to give a mixture of the formylated compound 34 and the amidine 33. The reaction conditions are of low influence on the ratio in which 33 and 34 are formed. The orthoamide 4b and 32 react to afford a mixture of the amidine 35 and the enamine 36. Hydrogensulfide acts on 3 giving N,N-dimethylthioformamide (37). From 3 and 1-alkynes 41 can be prepared the amidines 42. Hydrolysis of 42b affords phenylpropiolaldehyde (43). The alkylation of the aminalester 3 gives rise to the formation of vinylogous amidiniumsalts 1c and 1d, resp., additionally is formed the amide acetal 2a. The salt 1dcan also be prepared from 3 and borontrifluoride-ether. Iodide reacts with N,N-dimethylformamide acetals 12a,b in an unclear, complicated manner giving orthoesters 53, N,N-dimethylformamide, alkyliodides, alcohols, ammoniumiodides 46 and carbondioxide. The action of halogens on 3 affords the salts 1a,b,c,e,f depending on the chosen stoichiometric ratio. Aromatic aldehydes are suited for trapping azavinylogous carbenes formed on thermolysis of 3 — 1,3-oxazoles 69 are the reaction products. From 3 and propionaldehyde the amidine 65 can be obtained with low yield. Carbondisulfide transforms 3 to the azavinylogous salt 66. The preparation of the azavinylogous orthoamide 4ais described. The thermolysis of 3 and 4a, resp., gives rise to the formation of the triaminopyrimidine 67. Treatment of 1a with lithiumdiisopropylamide affords the triaminopyrazine 68, which can also be obtained by thermolysis of 3 in the presence of sodium hydride. Azavinylogous carbenes are thought to be the intermediates.

Molecular and crystal structure of ortho-tellurated azomethines with intramolecular N → Te coordination

Novel reactions have been discovered and studied of C aliph.–Te bond scission in o-butyltellurobenzalanilines under the action of halogens, which afford 2-halogenotellurenyl- and 2-trihalogenotellurobenzalanilnes in high yields. The series of azomethines have been synthesized with different tellurium-containing groups in o-positions with respect to the CN bond. The effects of structural factors upon the length of N → Te intramolecular coordination bonds have been studied by the following methods: X-ray structural determinations, dipole moments, 1H and 125Te NMR spectroscopy and IR spectroscopy. In Te II derivatives, the shortest intramolecular N→ Te contact (2.23 Å) is formed in 2-chlorotellurenyl derivatives XIIIb. Bis(2-formylphenyl)tellurium imines XIVa exist in the crystal form as 10-Te-3 telluranes, in which long intramolecular fractional N → Te bonds (2.70–2.72 Å) have been detected, with the basicity of the imine N atom no practical effect on their length. The 125Te NMR spectrum of the 15N labelled bis[2-(phenyl)iminomethinylphenyl]telluride shows that in solution of this compound a very fast (on an NMR timescale), Te–N and Te ← N bond scrambling occurs owing to a dynamic equilibrium between the topomeric 10-Te-3 structures that apparently takes place via the 12-Te-4 tellurane intermediates. The intramolecular coordination bond in the Te iv derivative, (2-phenyliminomethinyl-phenyl)butylmethyl telluronium perchlorate, belongs to the longest Te → N bonds (2.75 Å). For the first time, the 125Te– 15N spin-spin coupling constants are reported for a number of o-tellurated azomethines.

Thiocyanatomercuration des acetyleniques. Synthese de derives β-(iso)thiocyanatoalcenyl mercuriques, d'α-halo β-thiocyanato alcenes et de thiocyanato-1 alcynes-1

In the presence of (SCN) − mercuric chloride HgCl 2 adds to acetylenic compounds R 1CCR 2 affording in most cases α-chloromercuri-β-thiocyanatoalkenes R 1C(SCN)C(R 2)HgCl and if R 1 = R 2 = Et or n-Bu isothiocyanates R 1C(NCS)C(R 2)HgCl. The action of halogens or thio compounds affords α-halo-β-thiocyanatoalkenes. Most of the reported reactions are regio- and stereo-specific, in particular both RC(SCN)CHBr and RCBrCHSCN may be regiospecifically obtained from 1-alkynes RCCH. The synthesis of 1-thiocyanato-1-alkynes is also reported.

Zur Reaktion von Permethylcyclosilanen mit Halogenen

The series of α,ω-diiodopermethylpolysilanes, I(SiMe 2) n I, (n=4−6) andX(SiMe 2)4 X, (X=Cl, Br) has been prepared by the action of halogen on the corresponding cyclic compounds (SiMe 2) n . The mass spectra, NMR-, IR- andRaman-spectra of these compounds have been recorded.

Chlorinated organic derivatives with IrHg bonds

The reaction of ClHgR (R = 2.5-C 6H 3Cl 2; 2,3,4- and 2,4,6-C 6H 2Cl 3; C 6Cl 5 and C 2Cl 3) with trans-[IrCl(CO)(PPh 3) 2] gives the new stable compounds [(PPh 3) 2(CO)Cl 2IrHgR] which contain IrHg bonds. 31P NMR spectra indicate that the two phosphine are trans to each other in all the compounds; on the other hand, the HgR group is trans to Cl for the compounds with R = 2,5-C 6H 3Cl 2 and 2,3,4-C 6H 2Cl 3 whereas for R = C 6Cl 5 the HgR group is trans to CO. An equilibrium between the two isomers is established at room temperature for the compounds with R = C 2Cl 3 and 2,4,6-C 6H 2Cl 3. The complexes are probably formed by cis addition of ClHgR to trans-[Ir(CO)(PPh 3) 2] followed in some cases by isomerization reactions. The action of halogens and PPh 3 on the compounds is described.

Chemical properties of organotitanium compounds containing a ?silaneopentyl?" group

1. In the product from the reaction of titanium tetrachloride with 1,1,3,3-tetramethyl-1,3-disilacyclobutane Cl3TiCH2Si(CH3)2CH2Si(CH3)2Cl the Ti-C bond is thermally more stable than that in organotitanium trichlorides but is cleaved fairly readily by the action of halogen, hydrogen chloride, and by hydrolysis. 2. The enhanced reactivity of the C-Si bond adjacent to the titanium atom in thermolysis, hydrolysis, and cleavage with hydrogen chloride was established.

Oxydation par les halogènes de pyrrolidines stéroidiques conanine, méthyl-20 conanine et nor-21 conanine

The action of halogens in the presence of base on a 2-methyl-N-methyl pyrrolidine steroid (conanine) can, according to the nature of the halogen, (Br 2, Cl +, I 2) and the reaction conditions, lead selectively to an ammonium salt; a lactam (with loss of the methyl group) or to a piperidone. With iodine, the presencce of air and of light modifies the course of the reaction.

Action of halogens on organogold derivatives of ferrocene series

1. The reactions of 2-chloroferrocenyl(triphenylphosphine)gold and 2-(N,N-dimethylaminomethyl)-ferrocenyl(triphenylphosphine)gold with chlorine and bromine proceed via the step of forming the intermediate complexes of these compounds with a molecule of the halogen, and lead to the formation of 1,2-disubstituted ferrocenes, 2,2′-disubstituted biferrocenyls and triphenylphosphinegold halides. 2. On the example of the reaction of 2-(N,N-dimethylaminomethyl)ferrocenyl(triphenylphosphine)gold it was shown that of the two possible isomers of the substituted biferrocenyl only one, namely the symmetrical isomer, is obtained. 3. The reaction of 2-chloroferrocenyl(triphenylphosphine)gold with iodine gives only 1,2-chloroiodoferrocene and triphenylphosphinegold iodide.

The preparation of N- and C-halogen derivatives of 1, 2, 4-triazole

The action of halogens in an alkaline medium on 1, 2, 4-triazoles has given their N-chloro, N-bromo, and N-iodo derivatives. The formation of C-halogen derivatives of some 1, 2, 4-triazoles from their N-halogen derivatives has been studied, and also the action of halogens on 1, 2, 4-triazoles at elevated temperatures. It has been shown that N-bromo-1, 2, 4-triazoles very readily form 1, 2, 4-triazole and 3, 5-dibromo-1, 2, 4-triazole in approximately equimolar proportions. N-Chloro-1, 2, 4-triazole is more stable to the action of heat and forms 3-chloro-1, 2, 4-triazole with a yield of 40%. It was impossible to convert N-iodo-1, 2, 4-triazole into C-derivatives.

Synthesis, structure and reactions of chelate metal-olefin complexes

The results of a series of investigations of the behaviour of potential olefin— phosphine and olefin—arsine chelate groups with transition metals are presented. After a brief discussion of the nature of the metal—olefin bond the various types of reaction which are shown by C=C double bonds which are in close proximity with or are coordinated to a transition metal atom are summarized. The coordination, isornerization and oxidation reactions of ortho—chelate ligands with transition metals are then discussed. Some interesting intramolecular re-arrangements which are analogous with organic Wagner—Meerwein re-arrangements are discussed. INTRODUCTION AND SCOPE The object of this lecture is to attempt to bring together some recent advances in the chemistry of transition metal complexes containing chelate groups in which there is one c donor atom (charged or uncharged) and one or more olefin groups suitably located for possible coordination with the metal atom. Their synthesis, structure and reactions will be discussed. In particular, the action of halogens on those complexes which contain double bonds coordinated to, or in close proximity with, metal atoms will be considered in some detail. Of the many fundamental questions concerning the metal—carbon bond in transition metal complexes the following are of special interest: 1. What properties of the metal atom (formal charge thereon, electron configuration, nature of other ligands attached thereto, etc.) determine whether stable metal olefin bonds can be formed? 2. What is the effect of substituents in the olefin group on the stability of the metal—olefin bond. 3. What properties of the metal atom and the carbon ligand decide the stability of metal—carboncy bonds? 4. What factors determine the ease of change-over from metal—olefin to metal—carbon (cr) type bonds when reaction occurs with other reagents? To help answer some of these questions, we started, some years ago, to prepare a series of potential chelating olefin ligands containing at least one strong cr donor located geometrically so as to enable the double bond to be capable of being oriented in the appropriate position for coordination. This 127

Some properties of mixed organobimetallic compounds containing a bond between molybdenum (tungsten) and an element of group IVB

1. Reactions of C5H5(CO)3MSnPh3 and [C5H5(CO)3M]2(M=Mo, W) with halogens and hydrogen halides were conducted. Under the action of halogens there is a cleavage of the metal — metal bond, whereas under the action of hydrogen halides the phenyl ring is replaced by halogen, preserving the metal — metal bond. 2. An exchange of halogen atoms in the compounds [C5H5(CO)3M]2·SnCl2(M=Mo,W) for C5H5−, SCN−, ONO−, SC2H5−, C2H5− was conducted, and compounds with the corresponding functional groups at the tin atom, preserving the metal-metal bond, were obtained. 3. The IR spectra of the compounds obtained were measured. On the basis of the frequencies of the valence vibrations of the CO groups, depending upon the substituent at the tin atom, the presence of a transmission of electronic influences through the metal-metal bond was demonstrated. 4. The data of the PMR spectrum show that substituents at the tin atom have an appreciable influence on the values of the chemical shifts. The chemical shifts increase with increasing electron-acceptor properties of the substituent.

Action of halogens and hydrogen halides on 1-vinylbarene

1. The double bond in 1-vinylbarene is capable of taking part in electrophilic addition reactions, although it has a considerably lower reactivity thanα-olefins. 2. Hydrogen chloride and bromide add to vinylbarene in the presence of AlCl3 according to Markovnikov's rule with the formation of 1-(α-chloroethyl)barene and l-(α-bromoethyl)barene, respectively. 3. The barene and neobarene nuclei undergo thermal chlorination, which takes place similarly to photochemical chlorination.

Butadiene sulphone chemistry. Part I. Addition reactions

Butadiene sulphone [2,5-dihydrothiophen dioxide (I)] and 2,3-dihydrothiophen dioxide (II) undergo addition reactions with hydrazine and with substituted hydrazines; either the NN- or the NN′-disubstituted hydrazine is formed, depending on the nature of the original substituent and on the reaction conditions. The NN′-compounds are readily oxidised to azo-compounds. The dihydrothiophen dioxides and substituted analogues also undergo the Michael reaction with donors such as malonic or cyanoacetic ester, benzyl cyanide, nitroparaffins, and acetophenone, and under special conditions with acetoacetic ester. Some further reactions of the adducts are described, including Nef reactions of the nitroalkyl derivatives (XV) which give acyltetrahydrothiophen dioxides. Addition of hydrogen cyanide occurs less readily than does the Michael addition. Hydriodic acid, but not hydrobromic acid, adds to 2,3-dihydrothiophen dioxide, and action of halogens in moderately concentrated nitric acid affords nitrate esters of halogenohydrins from which the halogenohydrins are readily formed by mild hydrolysis. Ammonium hydrogen sulphite readily adds to 2,3-dihydrothiophen dioxides to give the 3-sulphonic acid salts, which undergo the usual reactions.

Phenylgermanium derivatives of manganese carbonyl

1. As a result of the reactions of the sodium salt of manganese carbonyl with phenylgermanium halide derivatives, we produced bimetallic compounds: (C6H5)3GeMn(CO)5, (C6H5)2Ge[Mn(CO)5]2 and [(C6H5)2GeMn(CO5]2. 2. (C6H5)3GeMn(CO)4P(C6H5)3, (C6H5)3GeMn(CO)4As(C6H5)3 and (C6H5)3GeMn(CO)4Sb(C6H5)3 were produced by replacement of the CO groups in the bimetallic compounds by phosphines, arsines, and stibines. 3. Under the action of halogens on phenylgermanium derivatives of manganese carbonyl, we produced (C6H5)2BrGeMn(CO)5, (C6H5)Br2GeMn(CO)5, Br3GeMn(CO)5 and Cl3GeMn(CO)5.

Phenylgermanium and phenyltin derivatives of rhenium carbonyl

1. The reactions of organogermanium halides Ph4−nGeXn with the sodium salt of rhenium pentacarbonyl were used to produce Ph3GeRe(CO)5 and Ph2Ge[Re(CO)5]2. 2. The action of halogens (Br2) or hydrohalic acids (HCl) was used to produce Br3GeRe(CO)5 and\(\begin{gathered} Ph_2 GeRe\left( {CO} \right)_5 \hfill \\ | \hfill \\ Cl \hfill \\ \end{gathered} \). 3. In the reaction of PPh3, AsPh3, SbPh3with Ph3GeRe(CO)5 and Ph3SnRe(CO)5, the corresponding derivatives with the general formula Ph3M-Re(CO)4L, were obtained, where M=Ge, Sn; L=PPh3; AsPh3; SbPh3.