Azolopyrimidines and pyrimidoquinazolines from 4-chloropyrimidines

5-Cyano-3,4-dihydro-6-phenyl-2-substitutedpyrimidin-4-ones 1a-c reacted with phosphorus oxychloride to give the corresponding 4-chloropyrimidine derivatives IIa-c . Compounds IIa-c reacted with aniline and hydrazine to yield the 4-anilino, IIIa,e , and 4-hydrazino, IIIb-d derivatives. The 4-hydrazino analogues IIIb,c could be converted into the triazolo[4,3-c] and tetrazolo[4,5-c]pyrimidines IV and V by the action of carbon disulphide and nitrous acid, respectively. The reaction of IIb,c with phenylhydrazine afforded directly the 5-amino-4,6-diphenyl-6H-2-substitutedpyrazolo[3,4-d]pyrimidines VIa,b . The 4-chloro derivative IIa reacted with antrhanilic acid to form the 5-cyano-2,4-diphenyl-6-(o-carboxyphenylamino)pyrimidine VIII , which could be cyclised into the 4-cyano-1,3-diphenyl-10H-pyrimido[6,1-b]quinazolin-10-one IX by heating with acetic anhydride.     

Reaction of metal-Carbene complexes with vinyllithium reagents

The reaction of vinyllithium with (CO)₅CrC(OCH₃)C₆H₅ (Ic) at?78° followed by the treatment with HCl at ?78° gave 43% (Z)-1-methoxy-1-phenylpropene (IIIa) and 21% 1,4-dimethoxy-1,4-diphenyl-1,3-butadiene (IVa) and no trace of a vinylphenylcarbene complex or its expected decomposition products. IIIa and IVa are proposed to arise from electrophilic attack at the carbon-carbon double bond of a σ-allychromium intermediate. The reaction of phenyllithium with (CO)₅CrC(OCH₃)CH=CHC₆H₅ (V) gave 9% (CO)₅CrC(OCH₃)CH₂CH- (C₆H₅)₂(VI) and 17% (E)-1-methoxy-1,3-diphenylpropene (VII). Reaction of V with lithium diphenylcuprate gave 30% of the conjugate addition product VI.     

Aspects of the preparation of cyclohexenyl- and menthenylthioenynes via ring-opening of thiophenes

Treatment of 2,5-dimethyl-3-(1-menthenyl)4-bromothiophene (IIIa) and 2,5-dimethyl-3-(1-cyclohexenyl)4-bromothiophene (IIIb) with butyllithium gave the thiodienynes Va and Vb, respectively, via ring-opening of the corresponding 3-lithio derivatives. 2,5-Dimethyl-3-(1-menthenyl)-4-bromothiophene 1,1-dioxide (IV) gave the sulfone VI under similar conditions. The uv spectra of IIIa-b, IV, Va-b and some related compounds have been recorded and compared. The rotational barrier of compound VI was determined.     

Radiation-induced reduction of vanadium(IV) to vanadium(II) in aqueous picolinate-formate solutions

Quantitative reduction of V(IV)(pic) to V(III)(pic)_n and then to V(II)(pic)_n(1 ⩽ n ⩽3) occurs when N₂O-saturated formate solutions (pH 4.2–6.3) containing V(IV) and picolinic acid (2-carboxypyridine) are irradiated. Pulse radiolysis measurements show that CO^-₂ reacts with picolinate only when the N-atom is protonated (k = 2.7 × 10⁸ dm³ mol^-1 s^-1). Reduction of V(IV)(pic) and V(III)(pic)_n is effected by the electron adduct of the protonated picolinate (picH)^. with rate constants at pH 4.2 of (3.5 ± 0.2) × 10⁷ dm³ mol^-1 s^-1 for V(IV)(pic) and (6.9 ± 0.4) × 10⁸ dm³ mol^-1 s^-1 for V(III)(pic)_n. No reduction of V(II)(pic)_n is observed.     

Heterocycles. CLXIX. Barriers to rotation in some N,N-Dimethyl-N′-heteroaryl,N,N-Diethyl-N′-heteroaryl-substituted formamidines and N,N-Dimethyl-N′-heteroaryl-substituted acetamidines

The free energies of the rotational barriers, ΔG*, about ?CH? NMe₂ bond in N′-heteroaryl N,N-dimethylformamidines (A), about ?CH? NEt₂ bond in N-heteroaryl N,N-diethylformamidines (B), and about ?C(Me)? NMe₂ bond in N′-heteroaryl N,N-dimethylacetamidines (C) have been found to be in the range 17.5–20.1 kcal/mole for type A, 18.8–21.6 kcal/mole for type B and 13–14 kcal/mole or below for type C of compounds, respectively. The compounds of the types A and B exist in the forms IIa, IIIa, IV, V, and VI, while the compounds of the type C exist in the forms IIb and IIIb.     

Monomeric and polymeric structures of oxovanadium(IV) complexes with Schiff base ligands derived from (R,R)-2,4-pentanediamine: Synthesis and crystal structure

New tetradentate Schiff base–oxovanadium(IV) complexes which have electron donating or withdrawing groups at the 5-position of the salicylaldehyde moieties, [VO{Xsal-(R,R)-2,4-ptn}] (H₂{Xsal-(R,R)-2,4-ptn}: N,N′-di-Xsalicylidene-(R,R)-2,4-pentanediamine; X=5-MeO (methoxy), 5-Br, and 5-NO₂) were prepared. The structures and redox potentials for the V(V)/V(IV) couple of the complexes were compared with those of other [VO{Xsal-(R,R)-2,4-ptn}] (X=3-EtO (ethoxy), 3-MeO, and H). The 5-MeO substituted complex which has electron donating groups at the 5-position of the salicylaldehyde moieties forms a monomeric structure in the solid state. The 3-EtO substituted complex has both monomeric and polymeric structures. On the other hand, the other [VO{Xsal-(R,R)-2,4-ptn}] (X=H, 3-MeO, 5-Br, 5-NO₂) complexes have only polymeric structures. X-ray crystal structure analysis of [VO{5-MeOsal-(R,R)-2,4-ptn}]⋅CH₃OH (1) was carried out. Complex 1 has a monomeric five-coordinate square–pyramidal structure. The six-membered N–N chelate ring forms a distorted flattened boat form with two methyl groups in the axial positions.     

Siliciumorganische verbindungen: LXXVIII. Reduktive silylierung von konjugierten trienen zu 1,6-disilyl-dienen

The reductive silylation of 1,3,5-hexatriene (I) with trimethylsilyl chloride and magnesium affords 74% disilylhexadienes, consisting of 8% 1,4-bis(trimethylsilyl)-2,5-hexadiene (II) and 92% 1,6-bis(trimethylsilyl)-2,4-hexadiene (III). The isomers IIIa, IIIb and IIIc can be separated via the Dieis—Alder adducts. Maleic anhydride reacts with IIIa and IIIb to give the bis[(trimethylsilyl)methyl] derivatives of 4-cyclohexene-1,2-dicar?ylic acid anhydride (IVa and IVb), whereas IIIc does not react with maleic anhydride. By a reductive silylation reaction 3-methyl-l,3,5-hexatriene (V) gives the 1,6-bis-silylated 2,4-hexadienes VIa and VIb, which with maleic anhydride give the adducts VIIa and VIIb.     

Darstellung und eigenschaften von bis(μ-fumarato)bis[di(π-cyclopentadienyl)titan(IV)]; strukturuntersuchungen der reinen und der kristall-chloroform enthaltenden phase

The reaction of titanocene dichloride with disodium fumarate in the two-phase system H₂O/CHCl₃ yields bis(μ-fumarato)bis[di(π-cyclopentadienyl)titamum(IV)]. Crystal data for the pure compound (IIIa): monoclinic, P2₁/n, a 18.558(5), b 9.076(5), c 7.559(2) Å, β 101.69(2)°; Z = 2. Crystal data for a phase containing chloroform of crystallization (CHCl₃/Ti = $\text{1}\text{1}$) (IIIb): triclinic, P$\text{1}$, a 20.439(11), b 10.269(5), c 8.858(3) Å, α 112.18(3), β 93.93(5), γ 91.63(7)°; Z = 2 × 1. The three independent [(π-C₅H₅)₂TiOCOCHHOCO]₂ molecules differ in the puckering of their 14-membered rings and the geometry of their TiOC units.     

Cycloalkanes containing heterocyclic germanium,tin and lead

Treatment of the lithium reagent from 1,3-bis(trifluoromethyl)benzene (I) with carbon dioxide gave a 60/40 mixture of 2,4- and 2,6-bis(trifluoromethyl)-benzoic acids (IV) and (II). The lithiation/carbonation of 1,3-bis(trifluoromethyl)benzene-5-d (VIII) gave (II) and (IV) without loss of deutrium. This result indicates that (I), unlike trifluoromethylbenzene, does not lithiate meta to a CF₃ group.     

Preparation,properties and reactivities of novel platinum compounds containing a thiomethoxymethyl group

Oxidative addition of ClCH₂SCH₃ to PtL₄ afforded trans-PtL₂(CH₂SCH₃)Cl (Ia, L = Ph₃P;Ib, L = MePh₂P). Treatment of I with NH₄PF₆ or Et₃OBF₄ in CH₂C1₂ gave ionic species, [PtL₂(CH₂SCH₃)]X (II, L = Ph₃P, MePh₂P, X = BF₄, PF₆), while similar treatment with MeSO₃F in benzene yielded a new type of stable dimethylsulfonium methylide—platinum complex, trans-[PtL₂(CH₂SMe₂)Cl] SO₃F (IIIa, L = Ph₃P; IIIb, L = MePh₂P). Action of H₂O₂ on Ia gave [Pt(Ph₃P)(μ-CH₂SCH₃)C1]₂ (IV) and its triphenylarsine analog, [Pt(Ph₃As)(μ-CH₂SCH₃)C1]₂ (V) was prepared in one step by oxidative addition of ClCH₂SCH₃ to Pt(AsPh₃)₄. The structural difference between [Pt(Ph₃P)(μ-CH₂SCH₃)C1]₂ and Pd(Ph₃P)- (CH₂SCH₃)C1 is discussed in terms of the difference in the ionization potential from d¹⁰ to d⁸ electronic state of metals.     

The chemical behaviour of the azido group bonded to copper(I): Synthesis and reactivity of thiothiatriazolato and alkynyl complexes

The copper(I) azido-derivatives, (PPh₃)(phen)CuN₃ (Ia) and (PPh₃)(TMP)CuN₃ (Ib) (phen = 1,10-phenanthroline; TMP = 3,4,7,8-tetramethyl-1,10-phenanthroline), obtained from [(PPh₃)₂CuN₃]₂ and the bidentate ligand (biL), react with CS₂ to give the thiothiatriazolato-copper(I) complexes, (PPh₃)(phen)Cu$\text{NC(S)SNN}$ (IIa) and (PPh₃)(TMP)Cu$\text{NC(S)SNN}$ (IIb). The preparation of IIa and IIb occurs only when free triphenylphosphine is present in the reaction medium. The isothiocyanate complexes, (PPh₃)(biL)Cu(NCS) (biL = phen, IIIa; biL = TMP, IIIb) are formed, instead of IIa and IIb, when free PPh₃ is not added to the reaction medium. The complexes IIIa and IIIb are also obtained when CH₂Cl₂ solutions of IIa and IIb are stirred for 15 h in the absence of light; if longer reaction times are used, the dimeric isothiocyanato complexes [(biL)Cu(NCS)]₂ are formed. Compounds IIa and IIb react with PhCOCl to give (PPh₃)(biL)CuCl and 4-benzoyl-1,2,3,4-thiatriazole-5-thione, PhCO$\text{NC(S)SNN}$.Treatment of Ia and Ib, or [(PPh₃)₂CuN₃]₂, with COS did not lead to isolation of characterizable products. An unsaturated molecule such as ethyl propriolate, EtO₂CCCH, does not behave as a 1,3-dipolarophile in its reactions with Ia and Ib, the alkynyl derivatives [(biL)Cu₂(CCCO₂Et)₂]_n (_n is probably 2; biL = phen, IVa; biL = TMP, IVb), being obtained. Similarly the azido-complex [(PPh₃)₂CuN₃]₂ reacts with ethyl propiolate to give the asymmetric binuclear alkynyl derivative, (PPh₃)₃Cu₂(CCCO₂Et)₂ (V). The reaction of V with hydrogen chloride gives EtO₂CCCH and the known complex (PPh₃)₃Cu₂Cl₂, confirming the above formulation. The reactions of V with neutral ligands such as TMP, phen and CyNC have also been studied, leading to the isolation of new copper(I) alkynyl-derivatives.     

Thermische Umwandlung von Phenyl-penta-2,4-dienyläthern in 4-[Penta-2,4-dienyl]-phenole als Beispiel für [5,5]-sigmatropische Umlagerungen. Vorläufige Mitteilung

The reaction between phenol and trans penta-2,4-dienyl chloride gave trans penta-2,4-dienyl Phenyl ether (I), whereas with a mixture of sorbyl chloride and 1-methylpenta-2,4-dienyl chloride, pure trans, trans hexa-2,4-dienyl phenyl ether (IV) and trans 1-methylpenta-2,4-dienyl phenyl ether (V) were obtained. The ether I gave, on heating in dilute solution at 185°, 4-(penta-2,4-dienyl)-phenol (III) as the main product, and also some 2-(2-vinylallyl)-phenol (II). The ether IV provided, on heating at 165°, in addition to the ortho CLAISEN rearrangement product VI, mainly a mixture consisting of 94% 4-(1-methylpenta-2,4-dienyl)-phenol (VIII) and only 6% 4-(hexa-2,4-dineyl)-phenol(IX). The latter product (IX) was the only para isomer produced on heating ether V, but in addition 22% of the ortho rearrangement product VII was formed. The migrations I → III, IV → VIII, and V → IX, proceeding through a ten membered transition state, are the first [5,5] sigmatropic rearrangements described.     

Preparation and characterization of new cycloplatinated carbene complexes

Reaction of iodotrimethylplatinum(IV) tetramer with bis(1,3-diphenyl-2-imidazolidinylidene) [(Hdpim)₂] gave a new dinuclear carbene complex, [{Pt(dpim)I}₂](dpim  1,3-diphenyl-2-imidazolidinylidenato-2-C,2′-C), III, in 84% yield, which contains a cycloplatinated carbene structure. Some mononuclear derivatives, [Pt(dpim)(acac)], [Pt(dpim)I{P(OCHMe₂)₃}], [Pt(dpim)-(NCCH₃)₂]ClO₄, and [Pt(dpim)(COD)]ClO₄ were prepared from III and characterized by means of elemental analysis, IR and NMR spectroscopy, and molar conductivity. An intermediate species, [{PtMeI(Hdpim)}₂], leading to III is discussed also.     

Alternative Synthesis and Crystal Structures of Titanocene(III)-β-Diketonate Complexes

Abstract

Reaction of titanocene prepared from Cp₂TiCl₂ and 2n-BuLi with β-diketones (β-diketone = 1-phenyl-1,3-butanedione, 1,3-diphenyl-1,3-propanedione, 3-methyl-2,4-pentanedione or 3-ethyl-2,4-pentanedione) afforded the titanocene(III) β-diketonate complex. The compounds [Ti(η⁵-Cp)₂(1-phenyl-1,3-butanedionate)] and [Ti(η⁵?Cp)₂(1,3-diphenyl-1,3-propanedionate)] have been characterized by X-ray crystallography.     

Reaction of dichlorosilanes with lithium in the presence of arylethylenes

The reaction of organodichlorosilanes (RR'Sil₂ and RSiHCl₂) and mono- or diarylethylenes with metallic lithium in tetrahydrofuran gives the corresponding substituted silacyclopentanes in 25–75% yield. The general character of the reaction is demonstrated and the optimal conditions are found. The suggested structure is completely confirmed by a study of certain physical and chemical properties of the aryl-substituted silacyclopentanes. IR and NMR spectra are presented. It has been demonstrated by gas-liquid chromatography and NMR spectroscopy that the x, x-diaryl-1,1-dialkyl-silacyclopentanes formed from RR'SiCl₂ ArCH=CH₂ and lithium contain several possible isomers, which result from the position of the aryl substituents relative to one another or to the plane of the salicyclopentane ring.Part of M. N. Manakov's dissertation [1].The authors express their sincere thanks to V. A. Shlyapochnikov, L. A. Leites, E. D. Lubuzh, V. I. Sheichenko, and S. V. Shlyapnikov for help in the spectroscopic and chromatographic analysis.     

SYNTHETIC,N.M.R. SPECTROSCOPIC AND X-RAY CRYSTALLOGRAPHIC INVESTIGATIONS ON THE PRODUCTS OF THE REACTIONS OF PHENYL (METHYL) PHOSPHONOTHIOIC DICHLORIDE AND THIOPHOSPHORYL CHLORIDE AND PSCL3 WITH PRIMARY AMINES

Abstract

The syntheses in solution of (i) 2,4-dialkylamino-, (ii) 2,4-dimethyl-, and (iii) 2,4-diphenyl-2,4-dithio-cyclodiphosph(V)azanes, [R′P(S)NR]₂ (R′ = NHR, Ph, or Me; R = alkyl), derived from thiophosphoryl trichloride, methylphosphonothioic and phenylphosphonothioic dichlorides and primary alkylamines are described. N.m.r. spectroscopic properties for these cyclodiphosph(V)azanes and their monomeric precursors, R′P(S)(NHR)₂ (R′ = NHR, Ph, or Me; R = alkyl), are presented and structural inferences are drawn from this data. The X-ray crystal structure of [PhP(S)NBuⁱ]₂ is reported.     

Synthesis of 5,6,7,8-tetrahydro-5-oxopyrido[2,3-d]pyrimidine-6-carbonitriles and -6-carboxylic acid esters

Dieckmann ring closure reactions of 4-[(2-cyanoethyl)substituted amino]-2-phenyl-5-pyrimidinecarboxylates (Ha-f) afforded several 5,6,7,8-tetrahydro-5-oxo-2-phenylpyrido[2,3-d]pyrimidine-6- carbonitriles (IIIa-f). The open-chain intermediates (IIa-f) were prepared by dechloroamination of 5-carbethoxy-4-chloro-2-phenylpyrimidine (1a) with several 3-substituted amino- propionitriles. Alkylation of the sodium salt of 5,6,7,8-tetrahydro-8-methyl-5-oxo-2-phenyl-pyrido[2,3-d]pyrimidine-6- carbonitrile (IIIa) with methyl iodide in DMF resulted in methylation at C-6 to afford IV. Tosylation of IIIa in pyridine gave the corresponding tosyl ester (V) of the enolic form. Oxidative dehydrogenation at the 6,7-position resulted when IIIa reacted with thionyl chloride, affording 5,8-dihydro-8-methyl-5-oxo-2-phenylpyrido[2,3-d]pyrimidine-6- carbonitrile (VII). Dechloroamination of la or 5-carbethoxy-4-chloro-2-methylthiopyrimidine (Ib) with ethyl 3-ethylaminopropionate followed by Dieckmann cyclization of the resulting open-chain intermediates gave the corresponding ethyl 5,6,7,8-tetrahydro-5-oxopyrido[2,3-d]pyrimidine-6-carboxylates IX'a and IX'b, respectively. These exist predominately in the enol form and undergo alkylation and oxidation reactions similar to IIIa.     

Metallacycloalkanes : II. Reactions of α,α′-bipyridyl-5-nickela-3,3,7,7-tetramethyl-trans-tricyclo[4.1.0.02,4]heptane

The title compound (II) underwent reductive elimination on treatment with maleic anhydride, tetracyanoethylene or triphenylphosphite to give 3,3,6,6,-tetramethyl-trans-tricyclo[3.1.0.0^2,4]hexane (III). With triphenylphosphite bi(2,2-dimethylcyclopropyl) (V) and 1-(2,2-dimethylcyclopropyl)-3-methyl-1,3-butadiene (VI) were also formed. Acidolysis of II with either HCl, malonic acid or methanol gave V. An intermediate complex α,α′-bipyridyl(phenoxy)-3-nickel-1,1′-bi-(2,2′-dimethylcyclopropyl) (VIII) was isolated by reaction of II with phenol. Methylene dibromide reacts with II to give III and 3,3,7,7-tetramethyl-trans-tricyclo[4.1.0.0^2,4]heptane (IV). With triethylaluminum and II complete exchange of the alkyl groups occurred and V was released on hydrolysis. Trifluoroborane diethyl ether and II gave 3,3,6,6-tetramethylcyclohexa-1,4-diene in a rearrangement-displacement reaction. The cyclodimerisation of 3,3-dimethylcyclopropene (I) to III catalysed by II and the fact that II can be recovered from the reaction mixture provides strong evidence for the intermediacy of metallacyclopentanes in these transition-metal-catalysed [2π + 2π] cyclo-additions.     

IR Study of a Polymer Proton-Conducting Electrolyte Based on Poly(vinyl alcohol) and Phenol-2,4-Disulfonic Acid

The structure and hydration of phenol-2,4-disulfonic acid in the individual state and in the system with poly(vinyl alcohol) at low and high humidity levels are studied by IR spectroscopy. It is shown that all characteristic features of the electrolytic dissociation of phenol-2,4-disulfonic acid via proton transfer from acid molecules to the molecules of water in the liquid phase of the binary system phenol-2,4-disulfonic acid–water are also observed for the viscous solutions of the triple system poly(vinyl alcohol)–phenol-2,4-disulfonic acid–water, although differences make themselves evident if water molecules are in deficiency. It is found that evacuation of the phenol-2,4-disulfonic acid film for several hours at room temperature leads to its dehydration and eventually causes formation of molecular dimers [C₆H₃OH(SO₂OH)₂]₂. A similar operation with the poly(vinyl alcohol)–phenol-2,4-disulfonic acid film is completed by the transfer of a proton from the acid molecule to the–ОН group of poly(vinyl alcohol) according to the following scheme: nC₆H₃OH(SO₂OH)₂ + (–CH₂OH) _n → nC₆H₃OH(SO₃)(SO₂OH)^– + (–CH₂OH₂) _n ⁺ .     

Electrochemistry of α, α'-dibromoketones: Reduction of 2,4-dibromo-1,5-diphenyl-1,4-pentadien-3-one (α,α'-dibromo-dibenzylidene acetone) at the mercury electrode

2,4-Dibromo-1,5-diphenyl-1,4-pentadien-3-one (VIII (PhCH=CBrCOCBr=CHPh, α, ga'-dibromodibenzylidene acetone) is electroreduced in “aprotic” dimethylformamide at the mercury electrode; E_1/2 of the first step is ?0.97 V vs. SCE; two electrons/molecule of VIII were transferred (c.p.e.) and two Br^?/molecule of VIII were released. The product was identified as cis-1,5-diphenyl-1-penten-4-yn-3-one(PhCH=CHCOC=CPh), which is the rearrangement product of an unstable dimethylenecyclopropanone. In MeOH solutions, electroreduction of VIII follows a different path, the first two-electron step being substituted by a four-electron step (c.p.e.), which furnishes 3,4-diphenyl-cyclopent-2-enone, XIII. XIII seems to be a rearrangement product of a cyclic precursor. Subsequent two-step reduction of this intermediate in MeOH affords finally 1,5-diphenylpentan-3-one(α, α'-dibenzylacetone).