Einfache Synthese von 3-Methyl-5,6-dihydro-2H-pyran-2-onen und 3-Methylcumarinen unter milden Bedingungen

Facile Synthesis of 3-Methyl-5,6-dihydro-2H-pyran-2-ones and 3-Methylcoumarines under Mild Conditions The synthesis of the 3-methyl-5,6-dihydro-2H-pyran-2-ones 3, 5 and the 3-methylcoumarines 7a—e from the β-hydroxyoxo compounds 1,4, 6a—c and the phosphonopropionic acid 2 under Wittig-Horner conditions is described.     

Zur Totalsynthese des 5-Acetoxy-6-methoxykawains

Total Synthesis of 5-Acetoxy-6-methoxykawain The oxidation of 5-hydroxy-4-methoxy-6-trans-styryl-2H-pyran-2-one ( 6 ) by periodic acid in methanol gives rise to racem.-4,6-dimethoxy-6-trans-styryl-2,5-pyrandione ( 7 ). The yield is 35% Compound 7 is the key intermediate¹⁾ for the total synthesis of (5S, 6S)-(+)-acetoxy-4,6-dimethoxy-6-trans-styryl-5,6-dihydro-2H-pyran-2-one ( 1 ).     

Synthese und Eigenschaften 6-substituierter 4-Alkoxy-5,6-dihydro-4H-thieno[3,2-b]pyrrol-5-one

Synthesis and Properties of 6-Substituted 4-Alkoxy-5,6-dihydro-4H-thieno[3,2-b]pyrrol-5-ones Reactions of the N-alkoxy-2-(2-thienyl)glycolamides 1B with dicyclohexylcarbodiimide yield the 4-alkoxy-5,6-dihydro-4H-thieno[3,2-b]pyrrol-5-ones 2b . Acid catalyzed methanolysis of the tetrahydropyranyl group in 2B, Bk results in the formation of the bicyclic lactams 5 .     

Umsetzung 3-substituierter 5,5-Dialkyl-2-oxo-5,6-dihydro-2Hpyrane mit Diazoalkanen

Reaction of 3-Substituted 5,5-Dialkyl-2-oxo-5,6-dihydro-2H-pyranes with Diazoalkanes The reaction of the 3-substituted 5,5-dialkyl-2-oxo-5,6-dihydro-2H-pyranes 1a-c with the diazoalkanes 2a-e leads to the compounds 3a-f , which are alkylated at position 4 , and to the products 4–6 of 1,3-dipolar cycloadditions. Product 4 exhibits coronar dilatory activity whereas compounds 5 and 6 show cardiodepressive activity.     

Synthesis and in vitro anti-HIV Activity of Certain 2-(1H-Benzimidazol-2-ylamino)pyrimidin-4(3H)-ones and Related Derivatives

In an ongoing effort to develop novel non-nucleoside human immunodeficiency virus inhibitors, a series of substituted 2-(1H-benzimidazol-2-ylamino)pyrimidin-4(3H)-ones and related derivatives were synthesized via cyclocondensation of 2-guanidino-1H-benzimidazole with diethyl ethoxymethylenemalonate, substituted diethyl malonates, some β-keto esters and 2-acetylbutyrolactone. From these series of compounds, 2-(1H-benzimidazol-2-ylamino)-6-hydroxy-5-phenylpyrimidin-4(3H)-ones ( 5f , NSC 666286) was confirmed to have a moderate in vitro anti-HIV activity.     

Synthesis of 6-substituted 2-phenyl-3-(5-substituted mercapto-1,3,4, thiadiazol-2-yl)quinazolin-4-(3H)-ones as antitubercular agents

2-Amino-5-mercapto-1,3,4-thiadiazole was condensed with various 6-substituted 2-phenylbenzoxazin-4 (3H)-ones to yield the compounds 1 . When these compounds were subjected to mercaptoetherification the title compounds 2–4 were obtained. They were screened for their antitubercular activity against Mycobacterium smegmatis and Mycobacterium tuberculosis H₃₇ Rv in vitro. Structure-activity relationships were established.     

Mehrcyclische Azine mit Heteroatomen in 1- und 3-Stellung, 25. Mitt.: 2-Amino-4-oxo-4H-3,1-benzothiazine: Darstellung,Dimroth-Umlagerung zu 4-Oxo-2-thioxo-1,2,3,4-tetrahydrochinazolinen und MS/MS-Fragmentierung

Polycyclic Azines, XXV: Benzoylthiourea derivatives 1–3 react on treatment with conc. H₂SO₄ to give 2-amino-3,1-benzothiazin-4-ones 4a–c . In contrast to lit. data 1 or 2 undergo cyclocondensation under modified conditions to give 2-benzoylamino-3,1-benzothiazin-4-ones 6a–c . Dimroth-Rearrangement of 4 affords quinazolin-2-thiones 5 . The mass spectral fragmentation of 4, 5 and 6 is discussed.     

Geraniinic acid derivative from the leaves of Phyllanthus reticulatus

Chemical constituents as well as cytotoxic and insecticidal activity of the crude methanol extract from the leaves of Phyllanthus reticulatus Poir. (Euphorbiaceae) were investigated. (5R*,6R*)-4,6-Dimethoxycarbonyl-5-[2′,3′,4′-trihydroxy-6′-(methoxycarbonyl) phenyl]-5,6-dihydro-2H-pyran-2-one (1) along with 3,4,3′-tri-O-methylellagic acid, and methyl gallate were isolated from the dichloromethane extract. Determination of their structures was based on spectroscopic analysis. Compound 1 possessed a very weak insecticidal activity against Spodoptera frugiperda (Sf9) with an IC₅₀ value of 27.27?μg/mL.     

Synthesis of [1,2,4]triazolo[3′,4′: 3,4] [1,2,4]triazino[5,6-b]indole derivatives and 3-substituted 5-ethyl-H-1,2,4-triazino[5,6-b] Indole

5-Ethyl-3-hydrazino-5H-1,2,4-triazino|5,6-b|indole ( 2 ) reacts with aromatic aldehydes in anhydrous ethanol to yield substituted arylidene-(5-ethyl-5H-1,2,4-triazino|5,6-b|indol-3-yl)hydrazones 3 . Treatment of 3 with excess SOCl₂ gave 10-ethyl-1-aryl-10H-| 1,2,4]triazolo|3′,4′:3,4| 1,2,4|triazino|5,6-b|indoles 4 , while the reaction of 2 with CS₂ in methanolic KOH afforded 10-ethyl-2,10-dihydro-1 H-| 1,2,4|triazolo|3′,4′3,4‖ 1,2,4|triazino|5,6-b|indol-1-thione ( 5 ). Fusion of 1 with aromatic amines leads to 3-(arylamino)-5-ethyl-5H-1,2,4-triazino|5,6-b|indoles 6 , whereas the reaction of 1 with alkyl or aralkyl halides in anhydrous acetone and in the presence of anhydrous K₂CO₃ results in the alkylation of the thiol group to give the alkylthio or aralkylthio derivatives 7.     

1,3-Bis(pyridin-2-ylthio)propan-2-one,Bis(thieno[2,3-b]pyridin-2-yl)-ketone und 5H-Bispyrido[3′,2′:4,5]thieno[2,3-b:2′,3′-e]pyridin-11-one

1,3-Bis(pyridin-2-ylthio)propan-2-ones, Bis(thieno[2,3-b]pyridin-2-yl)ketones and 5H-Bispyrido[3′,2′:4,5]thieno[2,3-b:2′,3′-e]pyridin-11-ones Reaction of 1a-d with 1,3-dichloroacetone gives the bissulphides 2a-d . Base catalyzed cyclization of 2a-d affords heterocyclically substituted ketones 3a-e . Treatment of 3a and 3b in conc. H₃PO₄ leads to the bispyridothienopyridines 5a and 5b .     

Synthesis and evaluation of in vitro antitubercular activity and antimicrobial activity of some novel 4H-chromeno[2,3-d]pyrimidine via 2-amino-4-phenyl-4H-chromene-3-carbonitriles

Novel 5-phenyl-1,5-dihydro-2H-chromeno[2,3-d]pyrimidine-2,4(3H)-dithiones, 5-phenyl-3,5-dihydro-4H-chromeno[2,3-d]pyrimidin-4-ones, 7-phenyl-7,9-dihydro-8H pyrimido[5′,4′:5,6]pyrano[3,2-h]quinolin-8-ones, and 4-amino-5-phenyl-1,5-dihydro-2H-chromeno[2,3-d]pyrimidine-2-thiones were synthesized form 2-amino-4-phenyl-4H-chromene-3-carbonitrile. The newly synthesized compounds were characterized by IR, ¹H-NMR, ¹³C-NMR, Mass spectra, and Elemental analysis. The compounds were evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H ₃₇ Rv and antibacterial activity against Staphylococcus Aureus [ATCC-25923] and Streptococcus pyogenes [MTCC-443] as Gram-positive, Escherichia coli [ATCC-25922], and Pseudomonas aeruginosa [MTCC-441] as Gram-negative bacterial strains and antifungal activity against Aspergillus niger [MTCC-282]. Some of these derivatives exhibited pronounced antitubercular and antimicrobial activities.     

Indoles,III Lactamisation of 4.9-Dihydropyrano [3.4-b]indol-1(3H)-ones. - A New Synthetic Route to the β-Carboline Ring System

Reaction of the pyrano[3.4-b]indolones 1a-d with aniline, benzylamine, phenylethylamine and propylamine at 200–210 °C yields the 2.3.4.9-tetrahydro-1H-pyrido[3.4-b]indol-1-ones 5a-j , which can be converted to the 2.3.4.9-tetrahydro-1H-pyrido[3.4-b]indoles 6a-j by reduction with LiAlH₄. After treatment with methylamine and 2 only the amides 3 and 4 could be isolated. Unsubstituted tetrahydro-β-carboline 7 is available by regioselective debenzylation of 6c .     

Synthesis of Some New Derivatives of Thiazolo[4,3-b]- and Thiazolo[2,3-b] quinazolone

The new 5H-thiazolo[4,3-b]quinazoline-3,5(1H)-diones 3, 4a–c, 5a–c and 5H-thiazolo[2,3-b]quinazoline-3,5(2H)-diones 9a–c, 11a–c were prepared by reaction of anthranilic acid with the 2-thiazolidinone-4-thione derivatives 1b, 6a–c, 7a–c and the 5-substituted 2-(alkylmercapto)-2-thiazolin-4-ones 8a-c, 10a-c , respectively.     

Synthesis and H2-antihistaminic activity of 2-amidino-1,2-dihydro-3h-pyrazol-3-ones

Synthesis and H₂-Antihistaminic Activity of 2-Amidino-1,2-dihydro-3H-pyrazol-3-ones The synthesis and the H₂-antihistaminic activity of 2-amidino-1,2-dihydro-3H-pyrazol-3-ones are reported.     

Ein neues Kawainolderivat aus Piper sanctum

A New Kavainol Derivative from Piper Sanctum From the wooden underground parts of Piper sanctum (5S,6S)-(+)-5-hydroxy-4,6-dimethoxy-6-trans-styryl-5,6-dihydro-2H-pyran-2-one ( 1 ) was isolated with 0.2 percent yield. Structure and absolute configuration of this compound have been assigned by comparison of its acetate with a previously described product 2 obtained from the same plant¹⁾.     

Synthesis and calcium channel antagonist activity of novel 1,4-dihydropyridine derivatives possessing 4-pyrone moieties

New 1,4-dihydropyridine derivatives were synthesized by introducing 4-pyrone ring systems at the 4-position of the dihydropyridine nucleus. These compounds were obtained according to Hantzsch reaction. 4-Pyrone carbaldehydes: 4-(4-oxo-6-phenyl-4H-pyran-2-yl)benzaldehyde 4a, 4-(6-methyl-4-oxo-4H-pyran-2-yl)benzaldehyde 4b, 4-oxo-6-phenyl-4H-pyran-2-carbaldehyde 7a, and 6-methyl-4-oxo-4H-pyran-2-carbaldehyde 7b were synthesized and used in these reactions. Then, the calcium channel blocking activity of some of these compounds were evaluated in which they showed weak effects.     

Untersuchungen an 1,3-Thiazinen, 37. Mitt. Umsetzungen NH-acider Tetrahydro-1,3-thiazinderivate mit Sulfensäure- und Sulfonsäurechloriden

Investigations on 1.3-Thiazines, XXXVII; Reactions of NH-acidic Tetrahydro-1.3-thiazine Derivatives with Sulfenic and Sulfonic Acid Chlorides N-sulfenyl derivatives were obtained from 5,6-dihydro-2H-1,3-thiazine-2.4(3H)-diones 1 and sulfenic acid chlorides in the presence of triethylamine or from the sodium salts of 1, 3. 2-Thioxo-tetrahydro-4H-1,3-thiazine-4-ones 4 were on the other hand sulfenylated at sulfur to 5 which was easily cleaved hydrolytically to 1 . N-Sulfonylation was only achieved with methane sulfonyl chloride to yield 13.     

Synthesis of [1,2,4]triazolo[3′,4′:3,4][1,2,4]triazino[5,6-b]indole,tetrazolo[5′,1′:3,4][1,2,4]triazino[5,6-b]indole and their Derivatives

Reactions of 5-ethyl 5H-1,2,4-triazino|5,6-b|indol-3-thione ( 1 ) with various reagents have been studied. 1 and hydrazine hydrate in anhydrous ethanol gave 5-ethyl-3-hydrazino-5H-1,2,4-triazino|5,6-b|indole ( 2 ). This compound was condensed with formic acid and acetic acid to give 10-ethyl-10H-|1,2,4|triazolo|3′,4′:3,4||1,2,4|triazino|5,6-b|indole ( 4 , R=H) and 10-ethyl-1 -methyl-10H-|1,2,4|triazolo-|3′,4′:3,4‖ 1,2,4|triazino|5,6-b|indole ( 4 , R = CH₃), respectively. Treatment of 2 with nitrous acid gave 10-ethyl-10H-tetrazolo|5′,1′:3,4‖ 1,2,4|triazino|5,6-b|indole ( 7 ). Interaction of 2 with acetylacetone in alcoholic KOH gave the pyrazole 8 , whereas reaction of 2 with ethyl acetoacetate in anhydrous ethanol led to the expected hydrazone 9 , which on reflux with alcoholic KOH gives 1-(5-ethyl-5H-1,2,4-triazino| 5,6-b|indol-3-yl)-3-methyl-2-pyrazolin-5-one 10 . Treatment of 2 with ethyl chloroformate gives 11 , which can be converted to 10-ethyl-2,10-dihydro-1H-|1,2,4|triazolo|3′,4′:3,4|triazino|5,6-b|-indol-1-one 12 by fusion.     

Synthese und Eigenschaften von 4-Alkoxy-5-imino-1,4-thiazinan-3-onen

Synthesis and Properties of 4-Alkoxy-5-imino-1,4-thiazinan-3-ones 2-(Cyanomethylthio)-2,2-diphenylacetic acid ( 5a ) reacts with alkoxyamines 2 and dicyclohexylcarbodiimide via the not isolated N-alkoxyamides 6a,b to yield the 4-alkoxy-5-imino-1,4-thiazinan-3-ones 7a,b . Reactions of the mono- and unsubstituted acids 5b,c with 2a–c afford primarily the N-alkoxyamides 6c–f , which undergo cyclisation to 7Ac–f in the presence of hydrogen chloride. Treatment of 7Ad,Af with sodium carbonate leads to the unstable bases 7d,f , which are converted to 8 with isocyanates. During the hydrolysis of 7Ad in hot ethanol, ring cleavage is observed leading to the diamide 9 , whereas 7Ab is transformed under the same conditions to 4-benzyloxy-2, 2-diphenyl-1,4-thiazinan-3,5-dione ( 10 )     

Iminiumkohlensäurederivat-Salze, 7. Mitt. Teil I: Elektrophile Reaktionen von 2-Methylthio-5,6-dihydro-4H1,3-thiaziniumiodiden, 2-Methylthio-4,5-dihydrothiazoliumiodiden und 2-Methylthio-5-methylthiazoliumiodiden mit N-Nucleophilen

Iminium Carbonic Acid Derivative Salts VII, Part I: Electrophilic Reactions of 2-Methylthio-5,6-dihydro-4H-1,3-thiazinium Iodides, 2-Methylthio-4,5-dihydrothiazolium Iodides, and 2-Methylthio-5-methylthiazolium Iodides with N-Nucleophiles Cyclic salts of the dithiocarbonic acid diester imidium type ( 3, 5 ) react with NH₂-nucleophiles to the cyclic isothioureas 6 – 8 . Some of these compounds were oxidized to cyclic isothiourea-S,S-dioxides ( 9, 10 ).