Synthesis,S-alkylation,and fungicidal activity of 4-(benzylideneamino)thioglycolurils

A series of 1,3-disubstituted 4-benzylideneamino-5-thioxohexahydroimidazo[4,5-d]imidazol-2(1H)-ones (thioglycolurils) was synthesized via the reaction of 5,7-disubstituted 3-thioxoperhydroimidazo[4,5-e]-1,2,4-triazin-6-ones with hydroxy-, alkoxy-, and fluorocontaining benzaldehyde derivatives. An alkylation of the obtained thioglycolurils with methyl iodide or 4-bromobenzyl bromide provided the corresponding 6-benzylideneamino-5-alkylsulfanyl-3,3a,6,6a-tetrahydroimidazo[4,5-d]imidazol-2(1H)-ones. The fungicidal activity of some synthesized compounds against pathogens causing diseases of agricultural crops was studied.     

Synthesis of 1,5-Disubstituted 3-(4-Hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-pyrazolines

A series of 1,5-disubstituted 3-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-pyrazolines were synthesized by the reaction of α,β-unsaturated ketones derived from dehydroacetic acid and hydrazine in hot acetic acid or propionic acid. The structures of all new compounds were elucidated by microanalyses, ¹H and ¹³C NMR, IR, and mass spectroscopic measurements.     

Single step synthesis of 2,3-dialkyl-6-nitro-quinazolin-4(3H)-imines and 3,5-dialkyl-9-nitro-imidazo[1,2-c]quinazolin-2(3H)-ones

A single step synthesis of 2,3-dialkyl-6-nitro-quinazolin-4(3H)-imines and 3,5-dialkyl-9-nitro-imidazo-[1,2-c]-quinazolin-2(3H)-ones from simple carbonyl compounds, primary amines or amino acid methyl esters and 2-azido-5-nitro-benzonitrile was developed. Key intermediates were N,N′-disubstituted amidines obtained by rearrangement of 4,5-dihydrotriazoles; the new heterocyclic rings were formed by spontaneous intramolecular reaction of the amino and cyano groups which are present in the intermediates.     

Synthesis of 1,5-Disubstituted 3-(4-Hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-pyrazolines

Summary. A series of 1,5-disubstituted 3-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-pyrazolines were synthesized by the reaction of α,β-unsaturated ketones derived from dehydroacetic acid and hydrazine in hot acetic acid or propionic acid. The structures of all new compounds were elucidated by microanalyses, ¹H and ¹³C NMR, IR, and mass spectroscopic measurements.     

Polyketides and nitrogenous metabolites from the endophytic fungus Phomopsis sp. D15a2a

Three new polyketides, phomopones A−C (1–3), one new cyclic tetrapeptide, 18-hydroxydihydrotentoxin (4), and a new amide, 6-hydroxyenamidin (5) together with a known derivative, enamindin (6) were obtained from the endophytic fungus Phomopsis sp. D15a2a isolated from the plant Alternanthera bettzickiana. The structures of the new compounds were elucidated by 1D, 2D NMR and HRMS data. The absolute configurations of the isolated metabolites were determined either by X-ray crystallography, Marfey’s method or by converting the compounds to Mosher esters.     

Identification and synthesis of volatiles released by the myxobacterium Chondromyces crocatus

Cultures of the myxobacterium Chondromyces crocatus on agar plates were analysed by closed-loop-stripping analysis or solid phase micro extraction. The odour profiles consist mainly of pyrazines, sesquiterpenoids and some aromatic compounds, summing up to more than 50 components. Several new pyrazines as 2-(1-hydroxy-1-methylethyl)-3-methoxypyrazine (9), 2-(1-hydroxy-1-methylpropyl)-3-methoxypyrazine (10), and 2-(1-hydroxy-2-methylpropyl)-3-methoxypyrazine (11) were identified besides several known pyrazines. A major pyrazine occurring in most samples was 2,5-bis-(1-methylethyl)pyrazine (3). While the well known sesquiterpenoid geosmin (1) was present in low amounts, the related compound (1(10)E,5E)-germacradien-11-ol (21) was identified in most samples in larger quantities. Other prominent sesquiterpenoids not reported before from microorganisms were (6S,10S)-6,10-dimethylbicyclo[4.4.0]dec-1-en-3-one (16), which was accompanied by smaller amounts of several derivatives. The biosynthesis of these compounds is discussed in relation to the recently proposed biosynthetic pathways to 1 and 21.     

Light-induced synthesis of 3,7-disubstituted bisisothiazolo[4,5-b:4′,5′-e]pyrazines from 3-substituted 4-dibromoamino-5-haloisothiazoles

A new procedure was developed for the synthesis of 3,7-disubstituted bisisothiazolo[4,5-b:4′,5′-e]pyrazines from 3-substituted 4-dibromoamino-5-haloisothiazoles under UV irradiation.N,N′-Bis(5-haloisothiazol-4-yl)diazenes were obtained as by-products. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1350–1352, July, 1999.     

Synthesis of coumarin based fluorescent compounds

The reaction of different 7,8-disubstituted coumarin 4-acetic acids with 7-diethylaminocoumarin-3-carbaldehyde in the presence of piperidine in methanol gives highly fluorescent (E)-1-(7-diethylaminocoumarin-3-yl)-2-(7,8-disubstituted coumarin-4-yl)ethenes in good yield. Only the (E) diastereomers of these are obtained. The compounds are new, orange to red in colour and show emission in yellow to red region. These compounds were further studied for their emission properties.     

Catalyst-free synthesis of N-rich heterocycles via multi-component reactions

Efficient and straightforward methods for the synthesis of 5-substituted 1H-tetrazoles via multi-component reaction of α-dicarbonyl compounds, 2,3-diaminomaleonitrile and sodium azide without any catalyst has been reported. These general protocols provide a wide variety of N-rich heterocyclic compounds (1H-tetrazole-5-yl) pyrazines and di(1H-tetrazole-5-yl) pyrazines, in good to excellent yields.     

Tubakialactones A–E,new polyketides from the endophytic fungus Tubakia sp. ECN-111

Three new isocoumarins and two new phthalides, tubakialactones A–E (1–5), together with three known polyketides including (R)-3,4-dihydro-4-hydroxyl-6,8-dimethoxy-4-methyl-3-methylene-1H-2-benzopyran-1-one (6), (?)-5,7-dimethoxy-3-methyl-1(3H)-isobenzofuranone (7), and isosclerone (8) were found in the endophytic fungus Tubakia sp. ECN-111 isolated from the leaves of Houttuynia cordata. The chemical structures of the new compounds were determined by spectroscopic analyses, including extensive 2D-NMR experiments. The absolute configuration of 3 and 7 was determined by optical rotation and circular dichroism.     

Chemical Constituents of a Formosan Soft Coral Sinularia sp.

A new marine sterol 7β-hydroperoxy-24-methylenecholesterol ( 1 ) along with five known compounds sarcophytol A ( 2 ), (Z)-N-[2-(4-hydroxyphenyl)ethyl]-3-methyldodec-2-enamide ( 3 ), 5α,7αH-eduesm-11(13)en-4α-ol ( 4 ), 24-methylenecholesterol ( 5 ) and 1β-hydroxy-α-cyperone ( 6 ) have been isolated from a Formosan soft coral Sinularia sp. The structures of the above compounds were determined by spectral analyses. Cytotoxicity of compounds 1–6 toward various cancer cell lines also is reported.     

Synthesis and characterization of 2-alkyl -5-{4-[(3-nitrophenyl-5-isoxazolyl)methoxy]phenyl}-2H-tetrazoles

Heteroaryl substituted analogs of antirhnoviral (A), was prepared by a convergent approach. 3-Nitrophenyl-5- bromooromethylisoxazoles 5a–b were synthesized by [3+2] cycloaddition of 3-(benzoyloxy)-propyne 2 to in situ generated arylnitrile oxides followed by deprotection of cycloadducts 3a–b and bromination of the resulting alcohols 4a–b. Coupling of 3- nitrophenyl-5-bromooromethylisoxazoles (5a–b) with 4-[5-(2-alkyl-2H-tetrazolyl)]phenols (6a–d) in N-methylpyrrolidinone under mild conditions afforded a new series of 2-alkyl-5-{4-[1-(3-nitrophenyl-5-isoxazolyl)methyloxy]phenylr}-2H-tetrazoles (7a–h) in high yields. The structures of the synthesized compounds were confirmed by their ¹H NMR, Mass spectral, and Elemental Analysis data.     

Design and synthesis of novel thiopheno-4-thiazolidinylindoles as potent antioxidant and antimicrobial agents

A novel and convenient synthesis of thiopheno-4-thiazolidinyl indole analogues is presented (IVa-IVi), with the aim of obtaining biologically active compounds. 3,5-disubstituted indol-2-carboxyhydrazides (Ia-If) were allowed to react with 3-acetyl-2,5-dichlorothiophene (II) to yield the corresponding 3,5-disubstituted indol-2-carbohydrazides (IIIa-IIIf). The pre-formed indolecarbohydrazides (IIIa-IIIf) were allowed to react with 2-mercaptoacetic acid or 2-mercaptopropanoic acid to produce thiopheno-4-thiazolidinylindoles (IVa-IVi). This reaction protocol affords a simple, eco-friendly, non-hazardous, easier preparation and high yields. The antioxidant (free radical scavenging, total antioxidant capacity and ferric-reducing antioxidant power) and antimicrobial activities of the synthesised compounds were evaluated. The structures and purity of the products were confirmed by their IR, ¹H NMR, ¹³C NMR and mass spectral and analytical data. Most of the compounds tested showed very significant scavenging, antioxidant and antimicrobial activities. Compounds containing electron donor group (CH₃) at the fifth position of indole exhibit an excellent ferric-reducing activity. The present study suggests that compounds IIIa-IIIb, IIIf, IVa-IVc, IVf-IVi, may serve as promising lead scaffolds for antioxidant and antimicrobial agents.     

(E)-3-Halo-2-styryl-4H-chromen-4-ones: synthesis and transformation to novel pyrazoles

New methods for the synthesis of (E)-3-halo-2-styryl-4H-chromen-4-ones were established. The reaction of these compounds with hydrazine hydrate afforded new and unexpected 3(5)-aryl-5(3)-[2-(2-hydroxyphenyl)-2-hydrazonoethyl]-1H-pyrazoles, which upon acid hydrolysis gave 3(5)-aryl-5(3)-[2-(2-hydroxyphenyl)-2-oxoethyl]-1H-pyrazoles. The reaction mechanisms for these transformations, involving 1,6- followed by 1,4-conjugate additions, are discussed and the structures of all new compounds were established by NMR studies.     

A New Cyclic Peptide and a New Steroid from the Fungus Penicillium sp. GD6 Isolated from the Mangrove Bruguiera gymnorrhiza

A rare new cyclic tetrapeptide, 5,5′‐epoxy‐MKN‐349A ( 1 ), featured by a MKN‐349A ( 5 ) skeleton and containing an uncommon ether bridge between C(5) and C(5′), and a new steroid, named 11‐O‐acetyl‐NGA0187 ( 2 ), together with two known steroids, 3 and 4 , were isolated from an endophytic fungus Penicillium sp. GD6 associated with the Chinese mangrove Bruguiera gymnorrhiza. The structures of the new compounds were elucidated on the basis of extensive spectroscopic analyses and by comparison with the data of related compounds reported in literature. Neither of the compounds 3 and 4 , isolated in this study, showed obvious bioactivities in the antibacterial bioassay experiments.     

New alkaloids and diterpenes from a deep ocean sediment derived fungus Penicillium sp.

Four new alkaloids, including two new meleagrin analogs, meleagrins B (2) and C (3), and two new diketopiperazines, roquefortines F (5) and G (6), together with six new diterpenes, conidiogenones B-G (7-12), were isolated from a deep ocean sediment derived fungus Penicillium sp. The structures and stereochemistry of the new compounds were elucidated by spectroscopic methods. The cytotoxicity of the new compounds against the HL-60, A-549, BEL-7402, and MOLT-4 cell lines was evaluated.     

Microwave-assisted and conventional synthesis of new phthalocyanines containing 4-(p-fluorophenyl)-3-methyl-4,5-dihydro-1H-1,2,4-triazol-5-one moieties

New metal-free and metal (Zn, Ni, Cu and Co) phthalocyanines containing 4-(p-fluorophenyl)-3-methyl-4,5-dihydro-1H-1,2,4-triazol-5-one moiety have been prepared from 1-(3,4-dicyanophenyl)-4-(p-fluorophenyl)-3-methyl-4,5-dihydro-1H-1,2,4-triazol-5-one by both conventional and microwave-assisted methods. All of these compounds are soluble in CHCl₃, DMF and DMSO. The new compounds have been characterized by elemental analysis, IR, NMR, UV-Vis spectroscopies. The crystal structures of compounds I and II were also determined by the single crystal diffraction technique.     

Substituted 5-(D,L-erythro-1′,2′-dihydroxypropyl)pyrazines. Potential precursors for the synthesis of biopterin derivatives

A convenient synthesis of substituted 5-( D,L )-erythro-1′,2′-dihydroxypropyl)pyrazines from crotonic acid 4 is described. The anomalous behavior during decarboxylation of functionalized 2-oximino-3-oxoesters 8a,b is noted. The structures of prepared compounds were determined by spectroscopic methods.     

Spongiains A-C: Three new spongian diterpenes with ring A rearrangement from the marine sponge Spongia sp.

Spongiains A-C (1–3), the first examples of spongian diterpenes bearing a pentacyclic skeleton composed of a fused 5/5/6/6/5 ring system through ring A rearrangement, together with four new spongian diterpenes, spongiains D-G (4–7), were isolated from the marine sponge Spongia sp.. The structures with absolute configurations of these compounds were elucidated by the methods of NMR, X-ray diffraction and quantum chemical approaches. The hypothetical biogenetic pathways as well as cytotoxic activities of 1–7 were also discussed.     

Synthesis, structural elucidation and biological activities of organotin(IV) derivatives of (E)-3-(4-methoxyphenyl)-2-(4-chlorophenyl)-2-propenoic acid

A new series of di- and tri-organotin(IV) compounds with the general formula R_4?n SnL _n , where R?=?Me (1,2), Et (3), n-Bu (4,5), n-Oct (6), Ph (7) and L?=?(E)-3-(4-methoxyphenyl)-2-(4-chlorophenyl)-2-propenoate, were synthesized by reaction of silver salt of ligand or ligand acid with diorganotin dichloride/oxide and triorganotin chloride in 2:1 and 1:1 molar ratio, respectively. These compounds were characterized by elemental analyses, FT-IR, multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR and mass spectrometry. The spectroscopic results revealed that all the diorganotin(IV) compounds possess trigonal bipyramidal structures in solution and octahedral geometry in the solid state around the tin atom. A linear polymeric trigonal bipyramidal structure in the solid state and a tetrahedral environment around the tin atom in non-coordinating solvents has been proposed for the triorganotin(IV) compounds. All synthesized compounds were tested in vitro against a number of microorganisms to assess their biocidal activity. These studies revealed that ligand acid and some of its organotin compounds show promising activity against different strains of bacteria and fungi but lowered than reference drugs.