Enantioselective Deprotonation of Cyclohexene Oxide to (R)-2-Cyclohexen-1-ol

The reaction of cyclohexene oxide with homochiral lithium amides, prepared from (S)-phenylglycine and (S)-valine has been studied and (R)-2-cyclohexen-1-ol 3 was prepared in a maximum of 72% ee. The optical purity was determined by ¹H NMR measurement of the α-methoxy-α-(trifluoromethyl)phenyl acetic acid (MTPA) derivative of the corresponding alcohol.     

Synthesis and Some Reactions of the Metal Phosphorus Double-bonded Complexes C5R5 (CO)2Mo=P(NMe2)2

Abstract

The reaction of the metalhydrides C₅R₅(CO)₃Mo-H (R=H (la), Me (lb) with P(NMe₂)₃ leads to the metal-phosphorus double-bonded species 2a,b via the intermediate formation of C₅(CO)₂ (Me₂N)₃P)Mo-H, which can only be identified spec-troscopically in solution.     

Comparison of Carboxamides Reactivity with Respect to Benzoyl Chloride and Diphenyl Chlorophosphate in Acetonitrile

For amides belonging to series RCONH₂ (I), RCONHMe (II), RCONHPh (III), and RCONMe₂ (IV) rate constants k₁ (l mol^-1 s^-1) were determined (in acetonitrile at 25°C) specifying the nucleophilic reactivity of the oxygen atom in amides toward benzoyl chloride and diphenyl chlorophosphate. The lack of substrate selectivity in the reactions in question was established. For equal values of inductive constants ^* of the R substituents the reactivity sequence of amides with respect to both substrates is the same (I >> IV > II, and III > II), and it does not follow the corresponding sequence of basicities. A conclusion was drawn that both groups of reactions proceed through cyclic transition states resembling reagents: six-membered with amides I and III, and five-membered with amides II and IV.     

A CONVENIENT SYNTHESIS OF 1,3-DISUBSTITUTED-4-(1′,3′-DITHIOLANE/DITHIANE-2′-YLIDENE)-2-PYRAZOLIN-5-ONES

1, 3 - Disubstituted- 4 - (1′, 3′- dithiolane /dithiane - 2′- ylidene) - 2 -pyrazolin-5-one derivatives like (1a–c), (2a–c), (3a–c) have been obtained by condensation of 2-pyrazolin-5-ones (1), (2) and (3) with carbon disulfide in presence of triethylamine followed by the reaction with 1,2-dibromoethane (4a), 1,3-dibromopropane (4b) and 1,3-dibromobutane (4c) respectively.     

Direct oxidative C(sp3)─H/C(sp2)─H coupling reaction using recyclable Sr-doped LaCoO3 perovskite catalyst

A strontium-doped lanthanum cobaltite perovskite, La_0.6Sr_0.4CoO₃, was prepared and utilized as a recyclable heterogeneous catalyst for the direct oxidative C(sp³)─H/C(sp²)─H coupling reaction between cyclic ethers and alkenes or coumarins to achieve corresponding α-functionalized ethers. The α-functionalization of cyclic thioethers or amides with alkenes or coumarins was also achieved via this protocol. The La_0.6Sr_0.4CoO₃ catalyst exhibited better performance than a variety of homogeneous and heterogeneous catalysts. Utilizing a recyclable catalyst would offer a greener option for the direct oxidative C(sp³)─H/C(sp²)─H coupling reaction. To our best knowledge, the C(sp³)─H/C(sp²)─H coupling between olefins and ethers to generate α-functionalized ethers using a heterogeneous catalyst has not been previously reported, and the α-functionalization of cyclic thioethers or amides with alkenes or coumarins is new.     

Synthesis of Some Novel 5-(Arylidene)-2-imino-3(pyridin-2-yl)thiazolidin-4-one Derivatives

Treatment of 2-aminopyridine ( 1 ) with chloroacetyl chloride in dry benzene gave 2-chloro-N-(pyridin-2-yl)acetamide ( 3 ), which on further reaction with potassium thiocyanate gave 2-imino-3-(pyridin-2-yl)thiazolidin-4-one ( 4 ) as an intermediate compound for the synthesis of pyridin-2-yl substituted 2-imino-thiazolidine-4-one derivatives. Cyclocondensation reaction of ( 4 ) with a series of aromatic aldehydes gave 5-arylidene derivatives of pyridin-2-yl substituted 2-imino-thiazolidine-4-ones 5a–j . ¹ H and ¹³C NMR spectroscopy, as well as elemental analyses, were used for the identification of these new compounds.     

Reaction of tris(2-hydroxyethyl)amine hydrochloride with zinc diacetate and bis(2-methylphenoxy)acetate

Reaction of tris(2-hydroxyethyl)amine hydrochloride Cl⁻ N⁺H(CH₂CH₂OH)₃ with zinc diacetate and bis(2-methylphenoxy)acetate in the molar ratio 2: 1 results in complexes 2[Cl⁻ N⁺H(CH₂CH₂OH)₃]^· Zn (OCOR)₂ (I, II) R= Me (I), 2-MeC₆H₄OCH₂ (II), which contain two protatrane cations linked with zinc diacylate by two coordination bonds HO → Zn. Complexes I and II are also formed by the reaction of the corresponding tris(2-hydroxyethyl)amine hydrochloride acylate RCOO⁻N⁺H(CH₂CH₂OH)₃ with ZnCl₂. The structure of complexes I, II is proved by elemental analysis, IR and ¹H, ¹³C, ¹⁵N NMR spectroscopy.     

REACTION OF 5,5-DIPHENYL-2-THIOHYDANTOIN WITH 1,4-DIBROMOBUTANE. THE CRYSTAL AND MOLECULAR STRUCTURE OF 2,3,4,5-TETRAHYDRO-7,7-DIPHENYLIMIDAZO-[2,1-b]-THIAZEPINE-8(7H)-ONE

Abstract

The reaction of 5,5-diphenyl-2-thiohydantoin (1) (DPTH) or its potassium salt (DPTH-K) with 1,4-dibromobutane gave two isomeric bicyclic products: 2,3,4,5-tetrahydro-7,7-diphenylimidazo-[2,1-b]-thiazepine-8(7H)-one (6) and 2,3,4,5-tetrahydro-8,8-diphenylimidazo-[2,1-b]-thiazepine-7(8)-one (7) in different ratios depending on the reaction conditions: [DPTH-K, EtOH, N-ethylpiperdine; phase transfer catalytical conditions: DPTH-K, Et₃N, benzene/water or DPTH acetone/K₂CO₃]. Compound (6) crystallizes in the space group P2₁/c with a = 10.4624(2), b = 8.3643(1), c = 18.4371(3) Å β = 96.3(1)°. The 7-membered thiazepine ring in (6) adopts a disordered chain conformation. The discussion of some physico-chemical properties and some factors showing the influence on the yield and ratios of isomeric compounds [(2), (3)], [(4), (5)] and [(6), (7)], obtained in the alkylation of DTPH (1) with dibromoalkanes, has been carried out.     

A Novel Method for the Synthesis of α,β‐Unsaturated Amides Mediated by Samarium Diiodide

Promoted by Samarium diiodide (SmI₂), α,β‐unsaturated amides were formed from nitrogen anions (formed in situ by the reduction of nitro compounds) and α,β‐unsaturated esters. This reaction contrasts with the conjugate addition between amines and α,β‐unsaturated esters promoted by samarium triiodide (SmI₃) and provides an alternative attractive way to obtain α,β‐unsaturated amides using SmI₂.     

New Syntheses of 2-Phenylsulphonylfurans

the synthesis of 2-phenylsulphonyltetrahydrofuran (1), 2-phenyl sulphonyl-5-methoxy-2,5-dihydrofuran (2) and 2-phenylsulphonylfuran (3) was carried out in very good yields and short reaction times starting from easily available precursors.     

A new butanolide from the leaves of <Emphasis Type="Italic">Cinnamomum reticulatum</Emphasis>

A new butanolide, isoreticulide ((4R,3E)-4-hydroxy-5-methylene-3-octadecylidenedihydrofuran-2-one) (1), along with nine compounds including one sesquiterpenoid, (3-methoxy-5H-9,11dioxabenzo[3,4]cyclohepta[1,2-f])inden-7-yl)-methanol (2); six benzenoids, p-hydroxybenzoic acid (3), p-hydroxybenzaldehyde (4), protocatechuic acid (5), ferulic acid (6), trans-methyl p-coumarate (7), and p-dihydrocoumaric acid (8), and two amides, N-trans-feruloyltyramine (9) and dihydroferuloyltyramine (10), were isolated from the leaves of Cinnamomum reticulatum Hayata (Lauraceae). These compounds were characterized and identified by physical and spectral evidence.     

Examining the binding mechanism of 3,4-dihydro-3-(2-oxo-2-phenylethylidene)-quinoxalin-2(1H)-one and its fragments to Cu2+

The structure and stoichiometries of the complexes that could be formed between Cu²⁺ and 3,4-dihydro-3-(2-oxo-2-phenylethylidene)-quinoxalin-2(1H)-one (1) were investigated by various spectral techniques such as IR, fluorescence, UV–vis and electron paramagnetic resonance. The results suggest that initially 3?:?1 and 2?:?1 (1/Cu²⁺) complexes are formed at low Cu²⁺ concentration and upon adding more Cu²⁺, 1?:?1 (preferred) and 1?:?2 complexes are generated. Since 1 possesses two possible binding sites, further exploration was done by testing the binding ability of Cu²⁺ to fragments of 1, namely β-enaminoketone derivatives (2–3) and quinoxaline-2-one (4), and by executing calculations of thermodynamic parameters of the reaction between 1 and Cu²⁺ in ethanol, optimized geometries of the possible complexes, and estimation of stability constants at various stoichiometries. Consequently, a step-by-step binding mechanism is suggested for formation of various complexes between 1 and Cu²⁺.     

PREPARATION AND MULTINUCLEAR NMR STUDY OF BENZOYL METHYLENE TRIPHENYLPHOSPHORNE AND BENZOYL METHYLENE TRI-N-BUTYLPHOSPHORANE PT (0) AND PD (0) COMPLEXES

The reactions of Pd (dba)₂ (dibenzylidene acetone palladium (0)) and Pt (dba)₂ (dibenzylidene acetone platinum (0)) with BPPY (Benzoyl Methylene Triphenylphosphorane) and BBuPY (Benzoyl MethyleneTri-n-butylphosphorane) in (1:2) ratios using tetrahydrofuran as solvent have yielded Pd (dba)(BPPY)₂ (1), [Pd (dba)(C(H)COPh(PPh₂-o-C₆H₄)][PPh₃CH₂COPh](2), Pd (dba)(BBuPY)₂ (3), and Pt (dba)(BPPY)₂ (4) complexes. Upon heating complex (1) in THF, a cyclization reaction occurred to give complex (2). The products (1), (2), (3), and (4) are studied by IR, ¹H, ³¹P, and ¹³C NMR technique.     

Synthesis,characterization, and DNA-binding of Ln(III) complexes with 2-hydroxybenzylidene-2-phenylquinoline-4-carbonylhydrazone

2-Hydroxybenzylidene-2-phenylquinoline-4-carbonylhydrazone (H₂L) and five Ln(III) complexes, [Ln(H₂L)(NO₃)₂]NO₃ [Ln = La (1), Pr (2), Sm (3), Eu (4), and Tb (5)], have been synthesized and characterized by ¹H NMR, elemental analysis, conductivity measurements, mass spectra, IR spectra, and UV spectra. The interaction of these complexes with calf thymus DNA was investigated by UV absorption spectroscopy, fluorescence spectroscopy, circular dichroism spectroscopy and viscosity measurements. Results suggest that these complexes bind to DNA via groove binding.     

Synthesis,characterization, and crystal structure determination of palladacycles of para-substituted 2-thiobenzylazobenzenes

Bichelated neutral palladacycles (1–3), [Pd(L)Cl], were synthesized from reaction of the new potential tridentate (C,N,S) ligands, 2-thiobenzylazobenzene (L₁), 4′-methyl-2-thiobenzylazobenzene (L₂), and 4′-chloro-2-thiobenzylazobenzene (L₃) with sodium tetrachloropalladate(II), Na₂[PdCl₄], in ethanol. The compounds were characterized by elemental analysis, FT-IR, ¹H NMR, UV–visible, and thermogravimetric analysis. The crystal structures of L₂ and 1–3 were determined by single-crystal X-ray diffraction. In 1–3, the geometry around palladium remains almost square planar, coordinated to carbon, nitrogen, and sulfur of the ligand forming a bichelated cyclopalladate complex. The C–H…Cl type intermolecular hydrogen bonds, weak π…π, C–H…π, and van der Waals interactions are believed to be the stabilizing forces for the crystal packing of these palladacycles.     

Diversity of supramolecular aggregation in copper(II) pentane-2,4-dionato compounds with methyl substituted 2-aminopyridines

Three copper(II) bis(pentane-2,4-dionato-κ ² O,O′) compounds with 2-amino-3-methylpyridine (2,3-ampy) (1), 2-amino-5-methylpyridine (2,5-ampy) (2), and 2-amino-4-methylpyridine (2,4-ampy) (3) were prepared by reaction of bis(pentane-2,4-dionato-κ ² O,O′)copper(II) with selected methyl substituted 2-aminopyridines. The coordination of Cu(II) in all three compounds is square pyramidal and intramolecular N–H?···?O hydrogen-bonding is present. X-ray crystallographic studies reveal different crystal aggregation influenced by a methyl substituent on pyridine. No intermolecular N–H?···?O hydrogen-bonding is present in 1. Intermolecular N–H?···?O hydrogen-bonding in 2 forms infinite chains and dimers are formed in 3. Extended 3-D aggregation was found in 2 via π–π and C–H?···?π (arene) interactions, while only chain formation was found in 1 and 3.     

Darstellung,Charakterisierung und Reaktionsverhalten von Natrium‐ und Kaliumhydridosilylamiden R2(H)Si—N(M)R′ (M = Na,K) — Kristallstruktur von [(Me3C)2(H)Si—N(K)SiMe3]2·THF

Preparation, Characterization and Reaction Behaviour of Sodium and Potassium Hydridosilylamides R₂(H)Si—N(M)R′ (M = Na, K) — Crystal Structure of [(Me₃C)₂(H)Si—N(K)SiMe₃]₂ · THF The alkali metal hydridosilylamides R₂(H)Si—N(M)R′ 1a‐Na — 1d—Na and 1a‐K — 1d‐K ( a : R = Me, R′ = CMe₃; b : R = Me, R′ = SiMe₃; c : R = Me, R′ = Si(H)Me₂; d : R = CMe₃, R′= SiMe₃) have been prepared by reaction of the corresponding hydridosilylamines 1a — 1d with alkali metal M (M = Na, K) in presence of styrene or with alkali metal hydrides MH (M = Na, K). With NaNH₂ in toluene Me₂(H)Si—NHCMe₃ ( 1a ) reacted not under metalation but under nucleophilic substitution of the H(Si) atom to give Me₂(NaNH)Si—NHCMe₃ ( 5 ). In the reaction of Me₂(H)Si—NHSiMe₃ ( 1b ) with NaNH₂ intoluene a mixture of Me₂(NaNH)Si—NHSiMe₃ and Me₂(H)Si—N(Na)SiMe₃ ( 1b‐Na ) was obtained. The hydridosilylamides have been characterized spectroscopically. The spectroscopic data of these amides and of the corresponding lithium derivatives are discussed. The ²⁹Si‐NMR‐chemical shifts and the ²⁹Si—¹H coupling constants of homologous alkali metal hydridosilylamides R₂(H)Si—N(M)R′ (M = Li, Na, K) are depending on the alkali metal. With increasing of the ionic character of the M—N bond M = K > Na > Li the ²⁹Si‐NMR‐signals are shifted upfield and the ²⁹Si—¹H coupling constants except for compounds (Me₃C)(H)Si—N(M)SiMe₃ are decreased. The reaction behaviour of the amides 1a‐Na — 1c‐Na and 1a‐K — 1c‐K was investigated toward chlorotrimethylsilane in tetrahydrofuran (THF) and in n‐pentane. In THF the amides produced just like the analogous lithium amides the corresponding N‐silylation products Me₂(H)Si—N(SiMe₃)R′ ( 2a — 2c ) in high yields. The reaction of the sodium amides with chlorotrimethylsilane in nonpolar solvent n‐pentane produced from 1a‐Na the cyclodisilazane [Me₂Si—NCMe₃]₂ ( 8a ), from 1b‐Na and 1‐Na mixtures of cyclodisilazane [Me₂Si—NR′]₂ ( 8b , 8c ) and N‐silylation product 2b , 2c . In contrast to 1b‐Na and 1c‐Na and to the analogous lithium amides the reaction of 1b‐K and 1c‐K with chlorotrimethylsilane afforded the N‐silylation products Me₂(H)Si—N(SiMe₃)R′ ( 2b , 2c ) in high yields. The amide [(Me₃C)₂(H)Si—N(K)SiMe₃]₂·THF ( 9 ) crystallizes in the space group C2/c with Z = 4. The central part of the molecule is a planar four‐membered K₂N₂ ring. One potassium atom is coordinated by two nitrogen atoms and the other one by two nitrogen atoms and one oxygen atom. Furthermore K···H(Si) and K···CH₃ contacts exist in 9 . The K—N distances in the K₂N₂ ring differ marginally.     

Synthesis of pyrazolopyrimidinones as sildenafil derivatives and sclerotigenin

A series of novel pyrazolo pyrimidinone derivatives (3(a–d), 4(a–d), and 6(a–d)) was synthesized from various pyrazolo amides (2a–d) which are synthesized by the reaction between ethyl 5-amino-3-methyl-1-phenyl-1H-pyrazole-4-carboxylate (1) and various lithium amides. In addition, we also described the synthesis of sclerotigenin drug molecule which has quinazoline moiety from simple 2-nitro benzoic acid with high yields.     

Synthesis and Characterization of New N-(Diphenylphosphino)-Naphthylamine Chalcogenides: X-Ray Structures of (1-NHC10H7)P(Se)Ph2 and Ph2P(S)OP(S)Ph2

Abstract

The reaction of 1-naphthylamine with one equivalent of chlorodiphenylphosphine in the presence of triethylamine gave the (1-NHC₁₀H₇)PPh₂ (1) ligand. Refluxing of 1 with elemental sulfur or grey selenium in toluene (1:1 molar ratio) afforded (1-NHC₁₀H₇)P(S)Ph₂ (2) and (1-NHC₁₀H₇)P(Se)Ph₂ (3), respectively. Moreover, the byproduct {Ph₂P(S)}₂O (4) was isolated from the reaction of 1 with elemental sulfur. Compounds 1–3 were identified and characterized by multinuclear (¹H, ¹³C, ³¹P, ⁷⁷Se) NMR spectroscopy, mass spectrometry, and elemental analysis. Crystal structure determinations of 3 and 4 were carried out.     

Über Reaktionen von Nitrosophenolen, 2. Mitt.: Reaktion von 1-Nitroso-2-naphthol mit Orein

Zusammenfassung In der vorliegenden Arbeit wurde die Reaktion von 1-Nitroso-2-naphthol mit Orcin in Äther bei Anwesenheit von HNO₃ studiert. Als Reaktionshauptprodukte wurden 11-Methylbenzo[a]-phenoxazon-(9) (1) sowie dessen 12-Oxid (2) isoliert. Der Reaktionsmechanismus und die Konstitution der erhaltenen Substanzen werden diskutiert. Ferner wurden auch 11-Methyl-5-hydroxy-benzo[a]phenoxazon-(9) (6), 11-Methyl-5-äthoxybenzo[a]phenoxazon-(9), 11-Methyl-5-methoxybenzo[a]phenoxazon-(9) (4), 11-Methyl-5-aminobenzo[a]phenoxazon-(9) (7) und 11-Methyl-5-anilinobenzo[a]phenoxazon-(9) (8) dargestellt.

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In this paper the reaction of 1-nitroso-2-naphthol with orcin in an ether medium in presence of HNO₃ is described. As main products 11-methylbenzo[a]phenoxazone-(9) (1) as well as its 12-oxide (2) were isolated. The reaction mechanism is presented. Identity of the reaction products is verified. 11-methyl-5-hydroxybenzo[a]phenoxazone-(9) (5), 11-methyl-5-methoxybenzo[a]phenoxazone-(9) (4), 11-methyl-5-aminobenzo[a]phenoxazone-(9) (7) and 11-methyl-5-anilinobenzo[a]phenoxazone-(9) (8) are prepared.

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