Synthesis of 1,3-dialkyl-5-(hetaryl-1-yl)-1,3-dihydrobenzimidazol-2-ones

Reactions of 5-amino-1,3-dialkyl-1,3-dihydrobenzimidazol-2-ones with 2,5-dimethoxytetrahydrofuran and 2,6-dimethyl-γ-pyranone led to the formation of 1,3-dialkyl-1,3-dihydro-5-(pyrrol-1-andл)benzimidazol-2-ones and 1-(1,3-dialkyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)-2,6-dimethylpyridin-4-ones.     

Synthesis of 2-substituted 5-(1,3-dithiolan-2-ylidene)-1,3-dioxane-4,6-dione derivatives

Some 2-substituted 5-(1,3-dithiolan-2-ylidene)-1,3-dioxane-4,6-dione derivatives 3 were prepared from the condensation reaction of 1,3-dithiolan-2-ylidenemalonic acid ( 2 ) with carbonyl compounds in 40–93% yields.     

Heterocyclic compounds from 2-(alkoxycarbonylcyanomethylene)-1,3-dioxolanes

2-(Alkoxycarbonylcyanomethylene)-1,3-dioxolanes reacted with hydrazines and hydroxylamine to yield 1-substituted 4-alkoxycarbonyl-5-amino-3-(2′-hydroxyethoxy)pyrazoles and 4-alkoxycarbonyl-5-amino-3-(2′-hydroxyethoxy)isoxazoles respectively. With guanidine and benzamidine 2-substituted (R = NH₂, C₆H₅) 5-cyano-6-(2′-hydroxyethoxy)pyrimidin-4-ones were obtained. Reaction of 2-(cyanomethoxycarbonylmethylene)-1,3-dioxolane with 1,3-diaminopropane afforded 2-(cyanomethoxycarbonylmethylene)-1,3-hexahydro-pyrimidine whereas treatment of the same compound with 4,5-dimethyl-1,2-phenylenediamine gave 2-(cyanomethoxycarbonylmethylene)-5,6-benzimidazoline. The structures of pyrazoles and pyrimidones were assigned on the basis of ¹H-{¹H} and ¹³C-{¹H}-nOe experiments.     

New 2-(benzothiazol-2-yl)-1,3-tropolones derived from 3,4,5,6-tetrachloro-1,2-benzoquinone

An acid-catalyzed reaction of substituted 5-chloro-2-methylbenzothiazoles with 3,4,5,6-tetrachloro-1,2-benzoquinone leads to 5,6,7-trichloro-2-(5-chlorobenzothiazol-2-yl)-1,3-tropolone and 4,5,6,7-tetrachloro-2-(5-chlorobenzothiazol-2-yl)-1,3-tropolone. Molecular structure of 4,5,6,7-tetrachloro-2-(5-chlorobenzothiazol-2-yl)-1,3-tropolone was established by X-ray crystallography.     

Cationic polymerizations of substituted 2-methylene-1,3-dioxocyclic acetals, 2-methylene-1,3-dithiolane and copolymerization of 2-methylene-1,3-dithiolane with 4-(t-butyl)-2-methylene-1,3-dioxolane1

Carbon black-supported sulfuric acid or BF₃·Et₂O-initiated polymerizations of 2-methylene-4,4,5,5-tetramethyl-1,3-dioxolane (1), 2-methylene-4-phenyl-1,3-dioxolane (2), and 2-methylene-4-isopropyl-5,5-dimethyl-1,3-dioxane (3) were performed. 1,2-Vinyl addition homopolymers of 1–3 were produced using carbon black-supported H₂SO₄ initiation at temperatures from 0°C to 60°C whereas both ring-opened and 1,2-vinyl structural units were present in the polymers using BF₃·Et₂O as an initiator. Cationic polymerizations of 2-methylene-1,3-dithiolane (4) and copolymerization of 4 with 2-methylene-4-(t-butyl)-1,3-dioxolane (5) were initiated with either carbon black-sulfuric acid or BF₃·Et₂O. Insoluble 1,2-vinyl addition homopolymers of 4 were obtained upon initiation with the supported acid or BF₃·Et₂O. A soluble copolymer of 2-methylene-1,3-dithiolane (4) and 4-(t-butyl)-2-methylene-1,3-dioxolane (5) was obtained upon BF₃·Et₂O initiation. This copolymer is composed of three structural units: a ring-opened dithioester unit, a 1,2-vinyl-polymerized 1,3-dithiolane unit, and a 1,2-vinyl polymerized 4-(t-butyl)-1,3-dioxolane unit. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2823–2840, 1999     

Molecular structures of methyl 4-[(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl]-1-methyl-1H-pyrazol-5-carboxylate and methyl 4-[(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl]-1-methyl-1H-pyrazol-3-carboxylate

The structure of methyl 4-[(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl]-1-methyl-1H-pyrazol-5-carboxylate is determined by X-ray crystallography and further used to elucidate the structure of methyl 4-[(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl]-1-methyl-1H-pyrazol-3-carboxylate, using the data of homo- and heteronuclear 2D NMR correlation spectroscopy.     

Synthesis of some new 3-[5-(2-oxo-2H-3-chromenyl)-1,3-oxazol-2-yl]-1,3-thiazolan-4-ones as antimicrobials

<正>A series of some new 2-imino-5-[(Z)-1-(4-methylphenyl)methylidene]-3-[5-(2-oxo-2H-3-chromenyl)-1,3-oxazol-2-yl]-1,3- thiazolan-4-ones 5a-j has been synthesized and assayed for their antibacterial activity against Gram-positive bacteria viz.Bacillus subtilis(ATCC 6633),Staphylococcus aureus(ATCC 6538p) and Micrococcus luteus(IFC 12708),and Gram-negative bacteria viz. Proteus vulgaris(ATCC 3851).Salmonella typhimurium(ATCC 14028) and Escherichia coli(ATCC 25922).Among the screened compounds,5d,5e,5f,5g,and 5j exhibited potent inhibitory activity compared to standard drug,and emerged as potential molecules for further development.     

Synthesis of 2-(dibenzosuberen-5-yl)-1,3-dicarbonyl compounds

Reaction of dibenzosuberen-5-ol with 1,3-dicarbonyl compounds catalyzed with scandium(III), copper(II), or indium(III) triflate (5 mol %) afforded 2-(dibenzosuberen-5-yl)-1,3-dicarbonyl compounds in 63–86% yield.     

Synthesis of New 2-(Oxiran-2-yl)-1,3-oxazoles

Russian Journal of General Chemistry - Reaction of 2-chloro-N-(2,2-dichloro-1-cyanovinyl)acetamide with dimethylamine gave 5-(dimethylamino)-2-[(dimethylamino)methyl]-1,3-oxazole-4-carbonitrile,...     

Electron-impact studies—XLVII: The mass spectra of 2-aryl-1,3-dithianes and -1,3-dithiolanes

The fragmentation patterns in the spectra of 2-aryl-1,3-dithianes and -1,3-dithiolanes have been elucidated by deuterium labelling studies. Ortho effects are observed in the spectra of 2(o-alkoxyphenyl)-1,3-dithianes. The molecular ions of the 1,3-dithianes eliminate S2H· and metastable kpeaks substantiate these eliminations. The hydrogen involved in this elimination randomises (C-4, 5 and 6) Prior to elimination in the spectrum of 2-phenyl-1,3-dithiane, but originates mainly from C-5 in that of the bis propane-1,3-dithioacetal of terephthaldehyde.     

New liquid crystal compounds ( )-4-[5-(2-Methylbutyl)-1,3-dioxan-2-yl]phenyl 4-alkoxybenzoate

New liquid crystal compounds, (+)-4-[5-(2-methylbutyl)-1,3-dioxan-2-yl] phenyl 4-alkoxybenzoates (5), were synthesized. The mesomorphic behaviour of these compounds is compared with that of (+)-4-(5-alkyl-1,3-dioxan-2-yl)-phenyl 4-(2-methylbutoxy)benzoates (6). While compounds 6 exhibited a chiral smectic C phase, the corresponding compounds 5 did not. This might mean that for the appearance of a chiral smectic C phase in these types of compounds, it is necessary that the carbonyl and the chiral groups exist at nearby positions. Transition temperatures to those isotropic state for compounds 5 were lower than those for compounds 6. This result is common in both cases of (+)-4-alkoxycarbonylphenyl-4-[5-(2-methylbutyl)-1,3-dioxan-2-yl]benzoates (7), and (+)-4-(2-methylbutoxy-carbonyl)phenyl 4-(5-alkyl-1,3-dioxan-2-yl)-benzoates (8).     

Synthesis of 2-(1-chloroalkyl)-1,3-benzodithioles and 2-alkylidene-1,3-benzodithioles

Boron trifluoride promoted transdithioacetalization of α-chloroacetals with 1,2-benzodithiol affords good yields of 2-(1-chloroalkyl)-1,3-benzodithioles, which dehydrochlorinates very satisfactorily to the corresponding 2-alkylidene-1,3-benzodithioles.     

Synthesis and some properties of 5-alkylamino-2-(phthalimidoalkyl)-1,3-oxazole-4-carbonitriles

5-Alkylamino-1,3-oxazole-4-carbonitriles containing a 2-phthalimidoethyl or 3-phthalimidopropyl substituent at position 2 of the oxazole ring were synthesized. In the reaction of 5-(morpholin-4-yl)-2-(2-phthalimidoethy)l-1,3-oxazole-4-carbonitrile with hydrazine hydrate, 2-(2-aminoethyl)-5-(morpholin-4-yl)-1,3-oxazole-4-carbonitrile is formed. In the case of the 3-phthalimidopropyl analog, the recyclization product 3-amino-2-(morpholin-4-ylcarbonyl)-6,7-dihydro-5H-pyrrolo[1,2-a]imidazole is formed.     

Heterocyclization of 2-(Propargylsulfanyl)-1,3-thiazole Derivatives by the Action of Halogens

Reactions of 2-(propargylsulfanyl)-5-methyl-1,3,4-thiadiazole, N-[5-(propargylsulfanyl)-1,3,4-thiadiazol- 2-yl]benzamide, 2-(propargylsulfanyl)-1,3-benzothiazole, and 2-(propargylsulfanyl)-4,5-dihydro-1,3- thiazole with iodine involved annulation of the unsaturated substituent with formation of fused thiazole ring. 2(5)-(Propargylsulfanyl)-1,3,4-thiadiazole derivatives reacted with bromine to give mixtures of heterocyclization products and bromine adducts to the triple bond. The bromination of 2-(propargylsulfanyl)-4,5-dihydro- 1,3-thiazole afforded only the bromine addition product to the triple bond.     

Synthesis of 3-[4-(1-Benzofuran-2-yl)-1,3-thiazol-2-yl]-2-(4-aryl)-1,3-thiazolidin-4-one Derivatives as Biological Agents

A protocol for the synthesis of 3-[4-(1-benzofuran-2-yl)-1,3-thiazol-2-yl]-2-(4-aryl)-1,3-thiazolidin-4-one derivatives (5a–e) has been developed from 1-(1-benzofuran-2-yl)-2-bromoethanone (2),which served as a key intermediate for the synthesis of the title compounds. The reaction of compound 2 with thiourea furnished 4-(1-benzofuran-2-yl)-1,3-thiazol-2-amine 3, which upon further reaction with various aromatic aldehydes, gave Schiff bases 4a–e. These Schiff bases, when treated with thioacetic acid in the presence of catalytic amount of anhydrous ZnCl₂, yielded thiazolidinone derivatives 5a–e. All the newly synthesized compounds have been characterized by analytical and spectral data and screened for their antimicrobial and analgesic activity.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Highly effective stereoselective synthesis of vinyl ethers of 5-alkyl-2-(2-furyl)-5-hydroxymethyl-1,3-dioxanes

The vinylation of cis-5-alkyl-5-hydroxymethyl-2-(2-furyl)-1,3-dioxanes in the KOH–DMSO system in acetylene at atmospheric or elevated pressures (85-100°C, 3 h) takes place stereoselectively and leads to the formation of cis-5-alkyl-2-(2-furyl)-5-vinyloxymethyl-1,3-dioxanes with yields of up to 93%.     

New π-electron donors: Ethanediylidene-2,2′-bis(1,3-diselenole) and ethanediylidene-2-(1,3-dithiole)-2′-(1,3-diselenole)

This communication describes synthesis and electrochemical properties of new type of π-donors containing 1,3-diselenole ring, ethanediylidene-2,2′-bis(1,3-diselenole)(1a) and ethanediylidene-2-(1,3-dithiole)-2′-(1,3-diselenole)(2a). The conductivities of the charge-transfer complexes of these donors with tetracyanoquinodimethane (TCNQ) are also demonstrated.     

A spectroscopic study of 1,3-dimethyl-2-(trimethylstannyl)-1,3-diaza-2-boracycloakanes

The vibrational spectra of 1,3-dimethyl-2-(trimethylstannyl)-1,3-diaza-2-boracyclopentane and the corresponding diazacyclohexane derivatives as well as those of some other 1,3-diaza-2-boracycloalkanes have been recorded. Boron-nitrogen valence vibrations are observed in the 1500±10 cm^?1 frequency region and boron-tin stretching is assigned near 760 cm^?1. These data are discussed in conjunction with the ¹¹B and ¹H NMR spectra of the various heterocycles and the tin Mössbauer spectra of the two boron-tin species.     

Amidine tautomerism in the 1,3-diacyl-2-(5-substituted furfuryl)thiourea series. Molecular structure of 1,3-diacetyl-2-(5-ethoxycarbonylfurfuryl)thiourea

The effect of substituents in the furan ring on the dynamics of amidine tautomerism in 1,3-diacetyl-2-(5-R-furfuryl)thioureas is demonstrated. The conformation of 1,3-diacetyl-2-(5-ethoxycarbonylfurfuryl)thiourea was established by x-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 741–745, June, 1991.     

Acetals and ethers,XVII. One- or two-step syntheses of 2-(2-alkoxyethyl)-1,3-dioxacyclanes

2-(2-Alkoxyethyl)-1,3-dioxanes (1) were prepared by ap-toluenesulfonic acid-catalyzed, one-step reaction of propenal with a mixture of aliphatic alcohol and trimethylene glycol in good yields. The transacetalization reaction of 1,1,3-trialkoxypropanes (3) with ethylene glycol or propylene-(1,2)glycol afforded good yields of pure 2-(2-alkoxyethyl)-1,3-dioxolanes (5 or6), respectively. This reaction proceeds through an intermediate 1,3-dialkoxy-1-(2-hydroxyalkoxy)-propane.

---

Ein- oder Zweistufensynthese von 2-(2-Alkoxyethyl)-1,3-dioxacyclanen

Zusammenfassung In der durchp-Toluolsulfonsäure — katalysierten, direkten Reaktion von Propenal mit einem Gemisch von aliphatischem Alkohol und Trimethylenglykol wurden die entsprechenden 2-(2-Alkoxyethyl)-1,3-dioxane (1) in guten Ausbeuten erhalten. Die Umacetalisierung von 1,1,3-Trialkoxypropanen (3) mit Ethylenglykol oder 1,2-Propylenglykol lieferte 2-(2-Alkoxyethyl)-1,3-dioxolane (5 oder6) in guten Ausbeuten. Die Umacetalisierungsreaktion von 1,1,3-Trialkoxypropanen verläuft über 1,3-Dialkoxy-1-(2-hydroxyalkoxy)-propane als Zwischenprodukte.