2-Polyfluoroalkylchromones. 5. Nitration and chlorination of 2-trifluoromethylchromones

Electrophilic nitration of 2-trifluoromethylchromone and its 6- and 7-methoxy derivatives affords 6-, 5-, and 8-nitro derivatives, respectively, while 5,7-dimethyl-2-trifluoromethylchromone yields a 6,8-dinitro derivative. Radical chlorination results in 3-chloro derivatives.     

Electrochemical partial fluorination of organic compounds. 74. Efficient anodic synthesis of 2-fluoro- and 2,3-difluoro-2,3-dihydrobenzofuran derivatives

Anodic fluorination of 3-substituted benzofuran derivatives in a variety of fluoride salts resulted in the formation of three fluorinated products; two stereoisomers of 2,3-difluoro-2,3-dihydrobenzofuran (cis and trans) and cis-2-fluoro-3-hydroxy-2,3-dihydrobenzofuran derivatives. Dehydrofluorination of the main products, cis-difluoro derivatives, furnished the nonaromatic 2-fluoro-3-benzofuranyledene derivatives instead of the aromatic 2-fluorobenzofuran derivatives.     

Research of benzimidazole derivatives. XXXVI. Synthesis and transformations of N-propargyl-substituted 2-aminobenzimidazoles

1-(2′-Propynyl)-2-aminobenzimidazole and 1,3-di(2′-propynyl)-2-iminobenzimidazoline, which are cyclized by the action of bases to imidazo[1,2-a]benzimidazole derivatives, were obtained by alkylation of 2-aminobenzimidazole with propargyl bromide. The cyclization proceeds with the formation of intermediate N-propadienyl derivatives.     

Synthesis of deoxy derivatives of lactose and their hydrolysis by beta-galactosidase from E. coli.

Methyl 2-deoxy-alpha-lactoside, methyl 3-deoxy-beta-lactoside, 1,5-anhydro-4-O-beta-D-galactopyranosyl-D-glucitol and the 2-deoxy and 2,3-dideoxy derivatives of 1,5-anhydro-4-O-beta-D-galactopyranosyl-D-glucitol have been synthesized by deoxygenation of lactose derivatives at appropriate positions. Cyclohexyl beta-D-galactopyranoside has also been synthesized. All derivatives proved to be substrates for the enzyme beta-galactosidase from E. coli, but the rate of hydrolysis of the substrate analogues was strongly dependent on the nature of the aglycone.     

Studies on the chemistry of pharmacologically active heterocycles. Part I. Acid hydrolysis of hydrazino-1,2,4-triazine derivatives

The acid hydrolysis of 3-hydrazino-5,6-disubstituted-1,2,4-triazine, 3,5-dihydrazino-6-substituted-1,2,4-triazine, and 2-hydrazinopyrimidine derivatives was studied. It was found that the reaction proceeded through the formation of 3-keto and 3,5-diketo derivatives of the related 2,3-dihydro, 2,3,4,5-tetrahydro-1,2,4-triazines, and 2-keto derivatives of 1,2-dihydropyrimidines. It was concluded from these reactions that in 1,2,4-triazine derivatives the C-5 carbon is more reactive than the C-3 carbon toward nucleophiles. The reaction mechanism is discussed.     

Diethylhydrogensilyl-cyclic diethylsilylene derivatives in gas chromatography-mass spectrometry of prostanoids. III. F alpha-prostaglandins and thromboxane B2 derivatives

The gas chromatographic (GC) and GC-mass spectrometric properties of the diethylhydrogensilyl-cyclic diethylsilylene (DEHS-DES) derivatives of prostaglandin (PG) F1 alpha methyl ester, PGF2 alpha methyl ester, 6-keto-PGF1 alpha methyl ester-alkyloxime and thromboxane (TX) B2 methyl ester-alkyloxime and the DES derivative of 13,14-dihydro-15-keto-PGF2 alpha methyl ester-alkyloxime were studied. When the ketonic PGs and TXB2 were converted into their methyloxime derivatives, the methylene unit values of these five prostanoid derivatives were slightly greater than those of the corresponding dimethylethylsilyl ether derivatives. When the ketonic PGs were converted into their corresponding ethyloxime derivatives, baseline separation was achieved in 20 min by use of a methylsilicone cross-linked fused-silica capillary column. The mass spectra of these derivatives were characterized by the ion at m/z 157 for F alpha prostaglandins and m/z 269 for TXB2. The major fragmentations were directed by the DES group, and other fragmentations common to the prostanoid derivatives were losses of an ethyl radical at the silicon atom, C5H11 hydrocarbon fragment, diethylhydrogensilanol and C15-C20 hydrocarbon fragment. The mass fragmentations of these prostanoid derivatives are briefly discussed. GC with high-resolution selected-ion monitoring was carried out for the TXB2 derivative at a resolution of 8000 by monitoring the ion at m/z 269.1573. A 25-pg amount of this derivative showed a well shaped doublet with a signal-to-noise ratio of more than 300:1.     

Functional derivatives of sterically hindered amines. 1. Glycidyl compounds

Four polymerizable glycidyl derivatives of sterically hindered amines were prepared from derivatives of 2, 2, 6, 6-tetramethyl-4-hydroxypiperidine and 14, 16-dioxo-7, 15-diazadispiro [5, 1, 5, 3] hexadecane. One of them is a stable nitroxyl derivative.     

Studies on the syntheses of heterocyclic compounds. Part CCCXXIX. Syntheses of i-spiroisoquinoline derivatives by phenolic cyclization

Phenolic cyclization of 2-(3-hydroxyphenyl)-2-methylethylamine (XIIIa) and 2-(3-hydroxyphenyl)phenethylamine (XIIIb) with various carbonyl compounds afforded eight types of corresponding 1-spirocycloalkano- and 1-spiroheterocycloalkano-1,2,3,4-tetrahydroisoquinoline derivatives (1-VIII) and 1,1-disubstituted-1, 2,3,4-tetrahydroisoquinoline derivative (IX). The acetyl derivatives of VI and IX and the benzoyl derivatives of III and V were also prepared. In addition, a synthetic method for obtaining the starting phenethylamines was examined.     

On triazoles. XII. The carbamoylation and thiocarbamoylation of 5-amino-1,2,4-triazoles

The reaction of 5-amino-3-R-1H-1,2,4-triazoles 1 with isocyanates 2 (X = O) and isothiocyanates 2 (X = S) was studied. It was stated that with isocyanates 3a (X = O) type ring-carbamoylated products were formed which did not rearrange to the corresponding exo-carbamoylated derivatives 6a (X = O). On the other hand the thiocarbamoylation of derivatives 1 provided at mild conditions lead to derivatives 3a (X = S) which could be rearranged by heating to derivatives 6a (X = S). In one case the isomeric 4a (X = S) type derivative was also isolated. The comparison of the ir, uv, pmr and cmr spectra of the isomers isolated with the corresponding spectra of the carbamoylated and thiocarbamoylated 3,5-diamino-1,2,4-triazole derivatives helped to prove unequivocally the isomeric and tautomeric structure of compounds obtained giving a possibility to correct many confusions in the literature.     

Chemical modification of fumagillin. II. 6-Amino-6-deoxyfumagillol and its derivatives.

6-Amino-6-deoxyfumagillol (5) was synthesized by reductive amination of 6-oxo-6-deoxyfumagillol (4), which was obtained by oxidation of fumagillol (2). The reduction proceeded stereoselectively by the equatorial attack of hydride and 5 was found to have the same stereochemistry as that of 2. Several derivatives of 5 were prepared and most of them showed anti-angiogenic activity comparable to that of fumagillol derivatives.     

Benzocycloheptapyridines. Analogs of azatadine

Certain 3-substituted derivatives of cyproheptadine ( 1a ) have been shown to possess potent pharmacological properties. The structural analogy between cyproheptadine and azatadine ( 2 ) prompted the preparation of 9-substituted derivatives of 2 and its 5,6-dehydro analog for pharmacological comparison. The 9-cyano and 9-trifluoromethylthio derivatives were prepared by direct displacement of the corresponding 9-bromo compounds. Acid hydrolysis of the nitriles generated the carboxylic acids. Oxidation of the trifluoromethylthio compounds 15a and 18a gave the epoxy sulfones 19a and 19b , which could not be deoxygenated. Therefore, the trifluoromethylsulfonyl moiety was introduced prior to the formation of the exocyclic olefin.     

A comparative,vapor-phase (G.L.C.-M.S.) study of various derivatives of prostaglandins A and B

The isomeric prostaglandins, A and B, can be readily distinguished by differences in the mass spectra of their derivatives. The mass spectra of the PGA₁- or PGA₂-methyl ester (ME)-trimethyl silyl (TMS) ether derivatives have a prominent ion at [M ? 71]⁺ or [M ? C₅H₁₁]⁺ while those of the PGB₁- or PGB₂-ME-TMS derivatives have a predominant ion at [M ? 99]⁺ or [M ? C₆H₁₁O]⁺ in addition to that at [M ? 71]⁺. Ions of similar origin characterize the spectra of the PGA₁- or PGA₂-TMS ether-TMS ester and PGB₁- or PGB₁-TMS-TMS derivatives, respectively. The fragmentation of other derivatives of PGA₁, PGA₂, PGB₁ and PGB₂ such as the ME-t-Bu-DMS (t-butyl-dimethylsilyl ether); ME-MO (methoxime)-TMS; ME-MO-Ac (acetate), and ME-Ac are also described comparatively. The composition of important ions was confirmed by deuterium labeling and/or high resolution mass spectroscopy, where appropriate. The potential advantages and limitations of the derivatives for quantitative analysis of prostaglandins by the specialized technique of multiple ion detection (MID) are described.     

A novel class of inhibitors for human steroid 5 alpha-reductase: phenoxybenzoic acid derivatives. I.

In a search for novel nonsteroidal inhibitors of human prostatic 5 alpha-reductase, we found a new series of phenoxybenzoic acid derivatives to be potent human prostatic 5 alpha-reductase inhibitors. Among them, 4-(biphenyl-4-yloxy)benzoic acid derivatives (2n, YM-31758), 2o and 2s showed more potent inhibitory activities than finasteride with IC50 values of 0.87, 0.67 and 0.56 nM, respectively. The optimized structures for the phenoxybenzoic acid derivatives 2d-2i were calculated by molecular modeling analysis, and the favorable distance between the carbon of the carboxyl group and the centroid of the phenyl group (benzene ring C) was found to be in the 9-11 A range.     

Head-to-tail regioregular oligothiophene-functionalized 9,9'-spirobifluorene derivatives. 1. Synthesis

Two series of novel fully conjugated oligomers, oligothiophene-functionalized 9,9'-spirobifluorene derivatives, have been developed in this contribution. First, four 9,9'-spirobifluorene bromide derivatives (compounds 1a-d) are prepared through various synthetic routes. Oligothiophene derivatives with or without substituents are synthesized through the Grignard and Suzuki coupling reactions. The Negishi coupling reactions between oligothienylzinc chloride and various 9,9'-spirobifluorene bromides with Pd(PPh(3))(4) as catalyst successfully produce the desired compounds, unsubstituted oligothiophene-functionalized 9,9'-spirobifluorene derivatives, compounds 2 to 4a-d. Since the Negishi coupling reactions afford regioregularly head-to-tail (H-T) oligo(4-n-hexylthiophene)-functionalized 9,9'-spirobifluorene derivatives in poor yields, the Suzuki coupling reactions between sodium 4-n-hexylthienyl-2-boronate 8, and various 9,9'-spirobifluorene-based bromides 1a-d and 9-16 are employed to produce highly regioregular head-to-tail oligothiophene-functionalized 9,9'-spirobifluorene derivatives (compounds 5 to 7a-d) in very high yields. We also investigate the effect of solvents on the Suzuki coupling reactions. The structure and purity of all compounds are verified by FT-IR, (1)H and (13)C NMR, MS, and elemental analysis.     

Neuraminic acid and related compounds. V. Syntheses of biologically active sialosyl-glycerol derivatives and galactosyl-glycerol derivative

New 1-acyl-sialosyl-glycerol derivatives (1a--d alpha, 1a--d beta, 2 alpha, 2 beta, which mimic the structure of the capsular polysaccharide of group C meningococcal were synthesized by the use of a chiral glycerol derivative, and were found to have phospholipases A2 and C inhibitory activities. Furthermore, synthesis of 2-palmitoyl-sialosyl-glycerol derivative (4 alpha, 4 beta, 5 alpha, 5 beta), galactosyl-glycerol derivative (6), and sialosyl-galactosyl-glycerol derivative (7) were carried out to examine the difference between these activities. Among these sialosyl derivatives, 3-palmitoyl-sialosyl-glycerol derivatives (1--3 alpha, 1--3 beta) demonstrated the most potent inhibitory activities.     

Synthesis and platelet aggregation inhibitory activity of diphenylazole derivatives. I. Thiazole and imidazole derivatives

Diphenylimidazole and diphenylthiazole derivatives were synthesized and tested as inhibitors of platelet aggregation in in vitro experiments with the rabbit. Diphenylthiazole derivatives (10) were more potent than diphenylimidazole derivatives (4) in inhibiting arachidonic acid-induced platelet aggregation of rabbit platelet-rich plasma. Two diphenylimidazole and eight diphenylthiazole derivatives were evaluated for ex vivo arachidonic acid and collagen-induced platelet aggregation inhibitory activity using guinea pigs. In these compounds, 4,5-bis(4-methoxyphenyl)-2-(1,5-dimethyl-2-pyrrolyl)thiazole (10n) showed strong activity in vitro and ex vivo. The ex vivo activity of 10n was 200 times stronger than that of aspirin. The mechanism of the activity of 10n was the inhibition of cyclo-oxygenase.     

Derivatives of 10,11-dihydro-5H-dibenzo[a,d] cycloheptene and related compounds. III. Azaketones

The preparation and properties of four isomeric azadibenzoeycloheptenones 3 and their 10,11-dihydro derivatives 2 are described. The ketones 2 were prepared by cyclization of appropriately substituted phenethylpyridine carboxylic acids and dehydrogenated to 3 . Four monochloro derivatives 24 of the 4-azaketone 2d are also described.     

Photorearrangement of phenyl selenide derivatives. Access to selenium substituted C-nucleosides

The photorearrangements of benzyl phenyl selenide and phenyl ribosyl selenide derivatives afford 2-benzyl phenylselenol and 2-ribosyl phenylselenol, respectively which can be isolated as their methyl derivatives.     

Nitrogen bridgehead compounds,part 68. Studies on quinolizine derivatives. Part 2. Synthesis of 1,3-disubstituted-4H-quinolizine derivatives

Quinolizine compounds 1 and 2 or their monocyclic tautomers 3 and 4 have been synthesized using 2-pyri-dineacetic acid derivatives 6a, b, A, B and ethoxymethylenemalonic acid derivatives 7a, b, c in base catalyzed or thermic reaction. In the 6-unsubstituted series, both the 4-oxo and 4-imino derivatives could have been obtained, in the 6-substituted series, however the 4-oxo ones only, whereas instead of the 4-imino derivatives, their monocyclic tautomers 3, 4 have been isolated. In the 6-unsubstituted series, the primarily formed 4-imino compounds have been rearranged into 4-oxo ones under stronger conditions. The structure of the isolated compounds have been proved by ultraviolet, infrared and ¹H nmr spectra, that of 3B=C by X-ray analysis as well.     

Thiazolidinone arylhydrazones. Ring cleavage and alkylation of the 5-arylhydrazone derivatives of rhodanine and isorhodanine

The 5-aryihydrazone derivatives of rhodanine and isorhodanine were subjected to the action of hydrazine hydrate to afford the arylhydrazonomercaptomethyltriazolinthione and -triazolinone derivatives 3 and 4 , respectively. Treatment of 1 with benzylamine afforded thioxalic acid dibenzylamide 5 . On the other hand, treatment of 2 with the same reagent afforded the corresponding benzylamino derivatives 6 . Alkylation of 1 and 2 with ethyl bromoacetate and chloroacetamide yielded the corresponding S-alkyl derivatives 7 and 8 , respectively.