Tri-component reaction of 2-alkyl-4,5-dichloropyridazin-3(2H)-ones: synthesis of 5-cyano-5-(pyrimidin-2-yl)-2,7-dialkyl-5H-dipyridazino-[4,5-b:4,5-e]-4H-thiopyran-1,6-dione and 2-(4-cyanophenoxy) pyrimidine

Reaction of 2-alkyl-4,5-dichloropyridazin-3(2H)-ones with p-cyanophenol and 2-mercaptopyrimidine in the presence of base gave 2,4,5-trisubstituted-pyridazin-3(2H)-ones 4-9, 2-(4-cyanophenoxy)pyrimidine (10) and 5-cyano-5-(pyrimidin-2-yl)-2,7-dialkyl-5H-dipyridazino[4,5-b:4,5-e]-4H-thiopyran-1,6-diones 11 as a novel heterocycle.     

Microwave-assisted Hantzsch thiazole synthesis of N-phenyl-4-(6-phenylimidazo[2,1-b]thiazol-5-yl)thiazol-2-amines from the reaction of 2-chloro-1-(6-phenylimidazo[2,1-b]thiazol-5-yl)ethanones and thioureas

N-Phenyl-4-(6-phenylimidazo[2,1-b]thiazol-5-yl)thiazol-2-amines (6a-q) have been synthesized by the Hantzsch thiazole reaction of 2-chloro-1-(6-phenylimidazo[2,1-b]thiazol-5-yl)ethanones (4a-e) with suitably substituted thioureas using microwave heating. The ethanones (4a-e) were prepared by the reaction of 6-phenylimidazo[2,1-b]thiazoles (3a-e) with chloroacetylchloride in refluxing 1,4-dioxane whereas the thiazoles (3a-e) were synthesized by the reaction of 2-bromo-1-phenylethanones (2a-e) with thiazol-2-amine in refluxing acetone.     

Synthese von (5,10)-(7,8)-Bisepoxiden aus α- und β-4-Phenyl-1,2,4-triazolin-3,5-dion-Addukten von Vitamin D3 und Röntgenstrukturanalyse eines der Benzoylderivate

Oxidation of the α- and β-4-phenyl-1,2,4-triazolin-3,5-dione adducts of vitamin D₃ (2 and1) withMCPBA yields two diastereomeric mixtures of the (5,10)-(7,8)-dioxiranes3 a,3 b,3 c and4 a,4 b respectively. The corresponding benzoates5 a,5 b,6 a and6 b were prepared and the X-ray crystal structure of5 b was determined. This analysis proved5 b to be the (5R, 1 OS)-(7R, 8R)-dioxirane of the β-resp. (6S)-4-phenyl-1,2,4-triazolin-3,5-dione adduct1 of vitamin D₃.     

Syntheses and spectroscopic characterization of double-armed benzo-15-crown-5 derivatives and their sodium and potassium complexes

A series of new benzo-15-crown-5 derivatives (1–6) containing formyl and imine groups were prepared. New formyl crown ethers (1 and 2) were prepared by reaction of 4′,5′-bis(bromomethyl)benzo-15-crown-5 with 2-hydroxy-3-methoxybenzaldehyde (o-vanillin) and 2-hydroxy-5-methoxybenzaldehyde in the presence of NaOH. New Schiff bases (3–6) were synthesized by the condensation of corresponding aldehydes with 1,3-diaminopropane and 1,4-diaminobutane. Sodium and potassium complexes (1a–6a and 1b–6b) of the crown compounds forming crystalline complexes of 1:1 (Na⁺:ligand) and 1:2 (K⁺:ligand) stoichiometries were also synthesized. The structures of the aldehydes 1 and 2, imines 3–6 and complexes (1a–3a and 1b–3b) were confirmed on the basis of elemental analyses, IR, ¹H- and ¹³C-NMR, and mass spectroscopy.     

Synthesis, reactions and antineoplastic activity of 3-(2-oxo-2H-chromen-3-yl)-2-oxo-2H,5H-pyrano[3,2-c]chromene derivatives

The key 3-(2-oxo-2H-chromen-3-yl)-2-oxo-2H,5H-pyrano[3,2-c]chromen-5-yl acetates 3 were synthesized in high yields by cyclocondensation of 4-oxo-4H-chromen-3-carbaldehydes 1 with coumarin-3-acetic acids 2 under mild conditions. The reaction pathway involves aldol condensation and subsequent intramolecular lactonization to afford 2-oxo-2H,5H-pyrano[3,2-c]chromene skeleton 3. Further treatment of acetates 3 with alcohols, water or nitrogen containing compounds led to 5-alkoxy-, 5-hydroxy- or 5-acylamino-2H,5H-pyrano[3,2-c]chromen-2-ones 4-6 via nucleophilic substitution of acetyloxy group at C-5. Acetates and hydroxyl derivatives 3 and 5 undergo facile rearrangement in an acid medium yielding 5-hydroxypyrano[2,3-b]chromen-2(10aH)-ones 7. Twelve prepared compounds were evaluated on their antineoplastic activities on 60 human tumour cell line panels in NCI USA. The obtained biological results confirmed that 3-(2-oxo-2H-chromen-3-yl)-2H,5H-pyrano[3,2-c]chromen-2-one represents a new leading skeleton suitable for further antitumour activity study.     

Reaktion der Tautomeren 4-Hydroxy-2H-thiopyran-2-thion und 2-Mercapto-4H-thiopyran-4-on mit aliphatischen Aldehyden

5,6-Dihydro-4-hydroxy-6,6-dimethyl-2H-thiopyrane-2-thione (1 I) and its tautomer 2-mercapto-4H-thiopyrane-4-one (1 II) react with aliphatic aldehydes under different reaction conditions to yield mainly 5R-7,8-dihydro-2H,5H,6H-thiopyrano[2,3—b:6,5—b′]-bisthiopyran-4,6(3H)-diones2 and 2′R,4′R-5,6,6′,7′-tetrahydro-2-thioxo-spiro(4H-thiopyran-3(2H), 3′(4′H)-2′H,5′H-thiopyrano-[2,3—b]-thiopyran)-4,5′-diones3. The mechanisms of formation of the condensates2 and3 and their stereochemistry are discussed. The reaction yielding2 is analogous to the condensation of dimedone with subsequent anhydride formation.3 might be generated byDiels-Adler reaction of intermediately formed 2-thioxo-3-alkylidenethiopyranones4. An X-ray crystal structure analysis was carried out on3 b to establish its configuration and conformation.     

Chinolizine und Indolizine,XIV Umlagerungen von Heterocyclen,X Ringumwandlungen von 1-Acyl-2-hydroxy-4-chinolizinonen

By heating with ammonia or aniline 1-acyl-2-hydroxy-4-quinolizinones (1 a–e) are transformed to 4-hydroxy-5-(2-pyridyl)-2-pyridones (3 a–f), with4 a–d as minor sideproducts. The structure of the rearranged compound3 f was established by an independent synthesis starting with6 and7. The reaction of1 a, d with ethyl β-aminocrotonate (β-ACE) yields pyrono-quinolizinones8 a, b and pyronopyridones9 a, b as byproducts; the latter are obtained in high yield by reaction of3 a, b with β-ACE. The ringtransformation reaction cannot be extended to 1-methoxycarbonyl-quinolizinones, such as10; in this case 2-amino-4-quinolizinone11 is the main product of the reaction with ammonia.     

Reactions of thioquinanthrene with alcoholates

Reactions of thioquinanthrene (1) with primary and secondary sodium alcoholates yielded sodium 4-[1-alkyl-4(1 H)-quinolon-3-ylthio]-3-quinoline-thiolates (2), which were characterized by theirS-methyl derivatives (total yields 70–90%).     

Über substituierte 2-Amino-3,4,5,6-tetrahydro-1H-pyrimidinium-und 1,2,3,4,6,7,8,9-Octahydropyrimido-[1,2—a]pyrimidiniumchloride

Crotonaldehyde resp. cinnamaldehyde react with guanidiniumchloride to give 2-amino-6-guanidinio-4-methyl-3.4.5.6-tetrahydro-1H-pyrimidiniumdichloride (4 a) resp. 6-hydroxy-4-phenylpyrimidiniumchloride3 b and the 4.6-dihydroxy-2.8-dimethyl (resp. 2.8-diphenyl)octahydropyrimido[1.2?a]pyrimidiniumchlorides6 a and6 b, resp. Action of 2.4-(or 2.6-)xylenol on4 a resp.3 b yields 2-amino-6-[2(or 4)-hydroxy-3.5-dimethylphenyl]-4-methyl-(resp. 4-phenyl)-3.4.5.6-tetrahydro-1H-pyrimidiniumchlorides (8 a resp.8 b or9 a resp.9 b), which are transformed to the zwitterionic compounds10 a–11 b by aqu. NaOH.6 a reacts with 2.4-xylenol to give the triazaoxabenzanthraceniumchlorid12 a·HCl (prove for the structure given for6 a). The chemical properties and the NMR-, UV-, mass- and IR-spectra of the compounds are discussed.     

Syntheses, spectroscopic characterization and metal ion binding properties of benzo-15-crown-5 derivatives and their sodium and nickel(II) complexes

New benzo-15-crown-5 derivatives containing nitro, amine and imine groups were prepared. Nitro compound (1) was prepared after the reaction?4′,5′-bis(bromethyl)benzo-15-crown-5 and o-nitrophenol in the presence of NaOH. After reduction process by using hydrazine hydrate and Pd/C amine compound (2) was formed. New crown ether imine compounds (3–5) were synthesized by the condensation of corresponding crown ether diamine (2) with salicylaldehyde derivatives. Sodium complexes of the crown compounds (1a–5a) form crystalline 1:1 (Na⁺: ligand) complexes with sodium perchlorate. Nickel(II) complexes (3b–5b) with 1:1 (Ni²⁺:ligand) stoichiometries were also been synthesized from the Schiff bases (3–5). The results indicated that the Schiff base ligands coordinated through the azomethine nitrogen and phenolic oxygen. The extraction ability of compounds (1, 3, 4 and 5) were also evaluated in chloroform by using several alkali and transition metal picrates such as Li⁺, Na⁺, K⁺, Cr³⁺, Mn²⁺, Ni²⁺, Cu²⁺, Zn²⁺ and Pb²⁺.     

Zur Chemie der 5-Alkylamino-4H-thiopyrano[2,3-b]pyridin-4-one

4-Alkylaminopyridinethiones · HCl (1 · HCl) react with bis-trichlorethylmalonate (3) predominantly to 5-alkylamino-4H-thiopyrano [2,3-b]pyridine-4-ones (6). With alcohols in the presence of acids at 25°C6 undergoes an alcoholysis to the corresponding alkyl-3-(2-thioxo-3-pyridyl)propionates (9). On heating in dilute alkali6 is hydrolysed via 4-alkylamino-2-thioxopyridyl-propylketones (11) to the tautomers, 4-hydroxy-2-thioxopyridylpropylketone (12 A) and 2-thioxo-3-(1-hydroxybutenyl)-4-piperidon (12 B), resp. On refluxing with alkali the ethyl-pyridylpropionate9 a is cyclisized to the 1-alkyl-1,6-naphthyridine-2(1H)-one (4 a), but boiling in ethanolic acid hydrolyses9 a via the pyridylpropionic acid10 to 4-alkyl-aminopyridylpropylketone (11 a). The latter can be transformed via the tautomers12 A,B and 2-methylthio-3-pyridylpropylketone (13) to the 4-hydroxy-3-butyrylpyridone (14 A) and its tautomer, 3-(1-hydroxy-butenyl)-piperidine-2,4-diones (14 B) resp. The structure of14 A,B is established by reaction of 4-isopropylamino-2(1H)-pyridone (2) with butanoylchloride to the 4-isopropylamino-3-butyrypyridone (15) and hydrolysis of15 to the tautomers14 A,B.     

An efficient 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU)-mediated synthesis of 5-(trifluoromethyl)-N-alkyl-1-(3-phenylisoquinoline-1-yl)-1H-pyrazole-4-carboxamides

A series of 5-(trifluoromethyl)-N-alkyl-1-(3-phenylisoquinoline-1-yl)-1H-pyrazole-4-carboxamides 4 has been effectively achieved in high yield and purity from the reaction of pyrazole carboxylic acid 2 with amines 3 in the presence of TBTU as a catalyst and diisopropyl ethylamine as a base in acetonitrile at room temperature.     

Synthese von Thiazolo[3,2−a]thieno[2,3−d]pyrimidin-Derivaten

Derivatives of 5H-thiazolo[3.2?a]thieno[2.3?d]pyrimidine(A), 5H-[1]benzothieno[2.3?d]thiazolo[3.2?a]pyrimidine (B), 4H-thiazolo[3.2?a]thieno[3.2?e]pyrimidine (C) and 5H-[1]benzo-thieno[3.2?e]thiazolo[3.2?a]pyrimidine (D) were synthesized by various methods. Similar reactions are leading to derivatives of thieno[2′.3′∶4.5]pyrimido[2.1?b][1.3]thiazine (E) and [1]benzothieno[2′.3′∶4.5]pyrimido[2.1?b][1.3]thiazine (F).C, D, E, andF are new heterocyclic ring systems. Detailed papers will appear soon.     

Untersuchungen über Synthesewege zu 2-Äthynyl-2-cyclopenten-1-onen

Synthetic approaches to 2-ethynyl-2-cyclopenten-1-ones (A) by dehydratation of the readily obtainable 2-(1-alkynyl)-2-hydroxy-cyclopentanones1 a and1 b were investigated. The synthesis of 2-(3,3,3-triphenylpropynyl)-2-cyclopenten-1-one (6) was achieved by reaction of 1-(3,3,3-triphenylpropynyl)-6-oxabicyclo[3.1.0]hexane (3 b) with HCl and CrO₃-oxidation of the resulting 2-(3,3,3-triphenylpropynyl)-2-cyclopenten-1-ol (4).     

Chemo- and diastereoselective control for a flexible approach to (5S,6S)-6-alkyl-5-benzyloxy-2-piperidinones

Chemo- and diastereoselective transformation of the N,O-acetals and their chain tautomers (4/5), readily derived from protected 3-hydroxyglutarimide 1a, was studied. It was uncovered that while the reaction with a combination of boron trifluoride etherate/zinc borohydride led to cyclic products (5S,6S/R)-6-alkyl-5-benzyloxy-2-piperidinones 3/2, and 6 in modest chemo- and diastereoselectivities, the reaction of 4/5 with zinc borohydride led exclusively to the formation of the ring-opening products 6 in excellent anti-diastereoselectivities. On the basis of the latter reaction, a flexible approach to (5S,6S)-6-alkyl-5-benzyloxy-2-piperidinones 3 was disclosed.     

Über die Synthese von 1,3-Dihydro-3-(2-dimethylaminoäthyl)-1-(3-thienyl)-benzimidazol-2-onen

The synthesis of 1-(3-thienyl)-benzimidazol-2-ones (3 a and4), described in an earlier paper¹, has been further investigated. The Na-salt of3 a is converted to a benzimidazolone substituted in position 3 (3 b). Dehydrogenation of the thiophene nucleus of3 a with chloranil yields5 a, which undergoes substitution in position 3 with Cl(CH₂)₂N(CH₃)₂ to give5 b. Monochlorination of5 a yields5 c, the structure of which is confirmed by¹H-NMR-spectroscopy.5 d is obtained by reaction of the Na-salt of5 c with Cl(CH₂)₂N(CH₃)₂.      

One-pot microwave-assisted solvent-free synthesis,theoretical and experimental studies on barrier rotation of C–N bond of N-alkenyl-1,2,3-triazoles

The reactions on benzotriazoles continue to happen to reach interesting varieties of their derivatives. This study reports a fast one-pot microwave-assisted solvent-free synthesis of N-alkenyl-1,2,3-benzotriazole (3, 5, and 7) and 1-(2-Alkyloxycarbonyl-vinyl)-1H-[1–3] triazole-4-carboxylic acid methyl ester (8 and 9) derivatives by nucleophilic addition reactions of 1,2,3-benzotriazole (C₆H₅N₃) (1) and 1H-[1–3] triazole-4-carboxylic acid methyl ester (C₄H₄N₃O₂) (1′) with R-propiolates (R = Me, Et; 2 & 4) and phenylacetylene 6 in good yields. The values of activation energy for rotation around C–N bond in the synthesized N-alkenyl-1,2,3-triazole compounds were studied by DFT-B3LYP/6-31G* method.     

Über die Bromierung von substituierten 3,4-Dihydro- und 6-Hydroxy- bzw. 6-Äthoxy-3,4,5,6-tetrahydro-2(1H)-pyrimidinonen

Bromination of 1-benzyl-4-methyl-3.4-dihydro-2(1H)-pyrimidinone (9 a) with 1 mole Br₂ in CHCl₃ yields 1-benzyl-5-bromo-6-hydroxy-4-methyltetrahydro-2(1H)-pyrimidinone,12 a, or the 6-ethoxypyrimidinone13 a, according to whether H₂O orEtOH is used in working up. With 2 moles Br₂,9 a analogously affords the 5.5-dibromopyrimidinnes14 a or15 a. Bromination of the 6-hydroxypyrimidinone10 a yields the same products,12 a and13 a, or14 a and15 a respectively, while the 4-phenyl-pyrimidinones9 b and11 b yield the corresponding 5-bromo-and 5.5-dibromopyrimidinones13 b and15 b. The structures of the compounds12 a-15 b are confirmed by their NMR data and chemical properties: the oxopyrimidinylmethylureas16 a and17 a are formed by the action of methylurea on12 a and13 a, or on14 a and15 a respectively; with hexamethylenetetramine,12 a reacts to give the 5.6-dihydroxypyrimidinone18 a, while13 b is transformed to the 4-phenylpyrimidinone19 b. 13 b was also synthesized from α-bromocinnamaldehyde. The mechanism of bromination is discussed.     

Zur sauren Hydrolyse von 1-(N-Methoxymethyl-thiocarbamoyl)-5-methyl-3,3-diphenyl-pyrrolidin-2-imin

The title compound (1) is hydrolysed at pH=0–2 to the new compounds 1-thiocarbamoyl-5-methyl-3.3-diphenylpyrrolidin-2-one (3) and the tetrahydrotriazine derivative (4). These compounds, together with 5-methyl-3.3.-diphenylpyrrolidin-2-imine (5), are the stable end-products of the reaction. The expected 5-methyl-3.3.-diphenyl-1-thiocarbamoyl-pyrrolidin-2-imine (6) is formed either as an intermediate or an end-product according to the conditions of hydrolysis. Its formation is analogous to that of the isomeric 5-methyl-3.3.-diphenyl-2-pyrrolidinylidene-thiourea (9) from 1-(N-methoxymethyl)-3-(5-methyl-3.3.-diphenyl)-2-pyrrolidinylidene)-thiourea (2) by cleavage of the methoxymethyl group.     

Synthesis and structure of lithium and rubidium compounds with 2-(diphenylacetyl)-1,3-indanedione

Complexes RbL (I) and [Li₂(C₂H₅OH)L₂] (II) (L = C₂₃H₁₅O₃) have been synthesized and their crystal structures have been studied. Both compounds have monoclinic crystals with space group P2₁/c and Z = 4; I: a = 11.632(2) Å, b = 15.154(3) Å, c = 11.457(2) Å, β = 104.34(3)°; II: a = 12.982(3)Å, b = 12.083(2) Å, c = 25.317(5) Å β = 100.11(3)°. In the structure of I, dimeric groups [Rb₂O₆] with a shared edge are linked by the ligands to give infinite layers perpendicular to the x axis and cavities that form oblong channels. In the structure of II, Li₂O₇ dimers are formed by vertex sharing. The coordination of one of the lithium atoms (Li(1)) is completed to tetrahedral by the oxygen atom of the ethanol molecule. The structure of II, like that of I, is layered.