Synthesis of analogs of amrinone: 4-(3,4-Disubstitutedphenyl)pyridines and derivatives thereof

4-(3,4-Dimethoxyphenyl)pyridine ( 5c ) prepared by the coupling of 3,4-dimethoxyphenyldiazonium chloride with pyridine was converted to 4-(4-pyridinyl)benzene-1,2-diol ( 6c ) by treating with hydrobromic acid. Diazotization of 4-(4-pyridinyl)benzeneamine ( 7 ) and 3-(4-pyridinyl)benzeneamine ( 12 ) gave the corresponding phenols 8 and 13 which were nitrated to give 2-nitro-4-(4-pyridinyl)phenol ( 9 ) and 2-nitro-5-(4-pyridinyl)-phenol ( 14 ), respectively. Reduction of these nitrophenols gave the corresponding aminophenols 10 and 16 which in turn were reacted with N,N'-carbonyldiimidazole to yield benzoxazolones 11 and 17 , respectively. Catalytic reduction of 2-nitro-4-(4-pyridinyl)benzeneamine ( 18 ) gave 4-(4-pyridinyl)benzene-1,2-diamine ( 19 ) which was reacted with orthoesters, urea, tetraethoxymethane, and N,N'-di(carbomethoxy)methylpseudothiourea to give the corresponding benzimidazole derivatives 20, 21, 22 , and 23 .     

Improvement in the synthesis of N,N'-diacyl-1,2-di(4-pyridyl)ethylenediamines

A better synthetic route to pharmacologically active N,N'-diacyl-1,2-di(4-pyridyl)ethylenediamines is described.     

Configurational assignments of the diastereomers of 3,3′‐(1,2‐ethanediyl)bis[2‐(3‐fluorophenyl)‐5‐methyl‐4‐thiazolidinone] derivative with four stereogenic centers

Diastereomers of antiinflammatory/analgesic and antihistaminic 3,3′[(1,2‐ethanediyl)bis(2‐aryl‐4‐thiazo‐lidinone)] derivatives possessing two stereogenic centers (indicated as BIS 2*C) have been widely investigated in recent years. The 5,5′‐dimethyl analogues (BIS 4*C), now reported, have been synthesized by reaction of (±) α‐mercaptopropionic acid and N,N'‐di(3‐fluorobenzyliden)ethylenediamine. Because the 2 and 2′carbons bear the same groups and similarly the 5 and 5′ carbons, and the latter groups are different from the former, four enantiomeric pairs and two meso forms exist in this situation. These diastereomers were identified by the concerted use of nmr spectroscopy and hplc on chiral stationary phase.     

Alkylation of pyridine-3,5-dicarboxamide and pyridine-3,5-dicarbonitriles by radical substitution

Structural modification of NAD(P) model compounds, N,N,N',N'-tetramethylpyridine-3,5-dicarboxamide ( 1 ), pyridine-3,5-dicarbonitrile ( 2 ), and 4-methylpyridine-3,5-dicarbonitrile ( 3 ), have been explored by the reaction with alkyl radicals such as the 1-adamantyl, tert-butyl, and isopropyl radicals. The alkyl substitutions of compounds 1 , 2 , and 3 with the 1-adamantyl and the tert-butyl radical gave both 2-mono and 2,6-disubstitution products, whereas the reaction of compound 2 with the isopropyl radical gave 2-mono 6c , 2,4-di 7c, 2,6-di 8c , and 2,4,6-trisubstitution 9c products.     

Alkylation of N-boc-1,2,3,4-tetrahydroisoquinolines in the 1-position and its application to the synthesis of isoquinoline alkaloids

Boc-protected 1,2,3,4-tetrahydroisoquinolines 2 can be lithiated with t-butyllithium in the presence of N,N,N',N',-tetramethylethylenediamine. Reaction of the anion with alkyl halides provides 1-alkyl N-Boc-1,2,3,4-tetrahydroisoquinolines in 67–71% yield. The protecting group is easily removed in high yield with trifluoroacetic acid. The alkaloids salsolidine ( 8 ) and laudanosine ( 11 ) were synthesized in racemic form using this method.     

Synthesis of bis-3-alkyl-5-arylhydantoins and bis-3-alkyl-5-arylthiohydantoins separated by two and four carbon atoms

Synthesis of 1,2- and 1,4-bis-thiohydantoins and hydantoins employing ethylenediamine and 1,4-diaminobutane as spacers is described. Compounds containing a two carbon bridge were synthesized by alkylation of ethylenediamine with two equivalents of N-t-butyl-α-(p-toluenesulfonyloxy)phenylacetamide 3 . The phenyl isothiocyanate adduct of 3 cyclized in refluxing toluene to form 1a . Other isothiocyanate or isocyanate adducts derived from alkylation product 4 required hydrolysis to induce cyclization. Compounds 1b-1f were obtained in this way. Compounds with a four carbon bridge were obtained by reaction of two equivalents of methyl α-bromophenyl acetate and 1,4-diaminobutane to produce N,N'-bis-[(α-phenyl-α-methoxycarbonyl)methyl]butylenediamine 6 . The isothiocyanate or isocyanate adducts from 6 cyclized, without hydrolysis, to form compounds 2a-2e .     

Complex Species in Aqueous Solutions of 4-Chloro-1,2-Phenylenediamine-N,N,N′,N,'-Tetraacetic Acid with Magnesium(II), Calcium(II), Strontium(II), Barium(II), Zinc(II) and Cadmium(II)

Abstract

The coordination in aqueous solution of 4-chloro-1,2-phenylenediamine-N',N',N',N'-tetraacetic acid (4-Cl-o-PDTA) with Be(II) and with the transition metal cations cobalt(II), nickel(II) and copper(II) was reported in earlier publications.^1,2 In this note a study is presented of the coordination in aqueous solution (25°C, 1 = 0.1 M in KC1) of 4-CI-o-PDTA acid with magnesium(II), calcium(II), strontium(II), barium(II), zinc(II) and cadmium(II).     

ELEMENTAL SULFUR REACTIONS WITH 2-PICOLINE

Abstract

A study of the reaction of the elemental sulfur with 2-picoline is reported. The process was carried out at the boiling point of the 2-picoline under argon. After removing unreacted solids, the reaction products were identified by means of LC. GC and GC-MS. The following products have been identified by mass spectrometry: 1,2-di/2-pyridyl/-ethane. 1,2-di/2-pyridyl/-ethene. 2-methyl-x-[/2-pyridyl/methyl]pyridines, 2-mercapto-methyl-[x/2-pyridyl/methyl]-pyridines, l-mercapto-1,2-di/2-pyridyl/-ethane, 5,6-di/2-pyridyl/-5H-cyclopenta-[b]pyridine, 5,6-di/2-pyridyl/-7H-cyclopenta[b]pyridine, 1,2,3-tri/2-pyridyl/-propane. 1,2-di/2-pyridyl/-1-[x-/2-methyl/-pyridyl]-ethane, 5,6-di/2-pyridyl/-7-[/2-pyridyl/methyl]-7H-cyclopenta[b]pyridine, 5,6-di/2-pyridyl/-5-[/2-pyridyl/-methyl]-5H-cyclopenta-[b]pyridine. Di{7-[5,6-di/2-pyridyl/-7H-cyclopenta[b]pyridyl]} sulfide and di(7-[5,6-di/2-pyridyl/-7H-cyclopentalblpyridyl]} disulfide.     

Synthesis of 5H-imidazo[5,1-a]isoindole: Photocyclization of N,N′ -bis(o-chlorobenzyl)imidazolium chloride and N-(o-chlorobenzyl)imidazole

A N-heterocyclic compound containing two hetero atoms, imidazo[5,1-a]isoindole, was synthesized in 40% yield by the intramolecular photocyclization of N,N'-bis(o-chlorobenzyl)imidazolium salts 1 in water (neutral or pH ～4) or of N-(o-chlorobenzyl)imidazole 2 , in aqueous acid (pH ?4). However, the photocyclized compound 3 was not formed effectively in basic aqueous solution (3 equivalents of sodium hydroxide or pyridine) or in acetonitrile by the photochemical reaction of N,N'-bis(o-chlorobenzyl)imidazolium salts 1 or N-(o-chlorobenzyl)imidazole (2).     

Proton-ionizable crown compounds. 20. The synthesis of polyazatriazolo-, polyazabistriazolo- and bispyridono-crown ligands containing lipophilic hydrocarbon substituents

Four new macrocyclic polyaza-crown compounds containing a triazole subcyclic group and two to five lipophilic hydrocarbon substituents have been prepared from the appropriate polyamine and N-THP-protected 2,5-triazoledimethyl dichloride. N,N,N',N'-Tetrabenzyltetraazabistriazolo-18-crown-6 was prepared from N,N'-dibenzylethylenediamine and N-THP-protected 2,5-triazoledimethyl dichloride. Biscyclohexano-bispyridono-18-crown-6 was prepared from trans- 1,2-cyclohexanediol and THP-protected 4-hydroxy-2,6-pyridinedimethyl ditosylate.     

Preparation of N,N′-di pivot lariat 1,4-diaza-15-crown-5 and 18-crown-6 macrocycles

Twelve diaza-15-crown-5 and 18-crown-6 macrocycles containing different side arms on the nitrogen atoms have been prepared. These diaza-N,N'-di pivot lariat crown ethers were prepared either from N,N'-bishydroxyethyl-1,4-diaza-15-crown-5 or 18-crown-6 ligands or from the corresponding unsubstituted diaza-crowns.     

Synthesis of 2-phenyl-1,3-di(4-pyridyl)naphthvalene by photoinduced reversible valence isomerization of 2-phenyl-1,3-di(4-pyridyl)naphthalene

2-Phenyl-1,3-di(4-pyridyl)naphthvalene 3a was synthesized by the photoinduced reversible valence isomerization of 2-phenyl-1,3-di(4-pyridyl)naphthalene 2a. Then, 3a was converted into 3-phenyl-1,2-di(4-pyridyl)naphthalene 4a and 2a simultaneously. The t_1/2 of 3a in DMSO-d₆ at 90 °C was 2 h, while that at 110 °C was approximately 10 min.     

Unusual Hydrogen-bonding Networks Consisting of π-Extended 4,4′-Bipyridines and Chloranilic Acid

Hydrogen-bonding networks of π-extended 4,4′-bipyridines, 2,5-di(4-pyridyl)thiophene (1), 2,5-di(4-pyridyl)furan (2) and 1,4-di(4-pyridyl)benzene (3) with 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid, CA) have been investigated. The dipyridyl compounds afforded complexes 4 [(dication of 1)·(monoanion of CA)²], 5 [(dication of 2)·(dianion of CA)·(MeOH)] and 6 [(3)·(dication of 3)·(dianion of CA)·(H²O)⁶] with CA. X-ray structure analyses revealed the formation of unusual molecular tape and sheet structures involving N–H ?O, O–H ?O, C–H ?O and N–H ?N hydrogen bonds, where the aromatic spacer groups play an important role in constructing the unique crystal structures.     

New 2‐methylisothiazolones

New N,N'‐bis(alkoxycarbonyl)‐L‐cystine bis(methylamides) 4a, 4b and N,N'‐bis(benzyloxycarbonyl)‐L‐cystine bis(methylamide) 4c have been synthesized by mixed anhydride method from the essential amino acid L‐cystine 1 in good yield. These cystine bis(methylamides) 4a,b,c have been cyclized with sulfuryl chloride. New 2‐methyl‐4‐amino‐3‐isothiazolone and 5‐chloro‐2‐methyl‐4‐amino‐3‐isothiazolone hydrobromide salts 7, 8 have been obtained by deacylation of 2‐methyl‐4‐(benzyloxycarbonyl)amino‐3‐isothiazolone 5c and 5‐chloro‐2‐methyl‐4‐(benzyloxycarbonyl)amino‐3‐isothiazolone 6c with hydrogen bromide in acetic acid. The microbicidal effect of the new 2‐methy]‐3‐isothiazolones 5a,b,c; 6a,b,c; 7 and 8 compounds obtained by the above method has been investigated.     

N-Heteroaralkyl substituted α-amidinium thiolsulfates

The syntheses of a number of N-substituted α-amidinium thiolsulfates, CH₂(S₂O₃^?)-C(=NH₂⁺)NH(CH₂)nR are described, where n was varied from 1 to 3 and R represents such heteroaryl groups as 2-furyl, 2-thienyl, 3-indolyl and 2-, 3- and 4-pyridyl. The preparation of S-(2-imidazolinemethyl)thiolsulfuric acid, as an example of an N, N'-disubstituted α-amidinium thiolsulfate, is also reported.     

The reactions of some pyranylideneiminium salts with amines. Part 1

The iminium salt, N,N-dimethyl-N-[2-(2,6-diphenyl-4H-pyran-4-ylidene)ethylidene]iminium perolilorate ( 1 ), reacts with secondary amines, such as piperidine, by exchanging the dimethyl-amino function for a piperidine. Primary amines react with 1 to give 1-alkyl-2-phenyl-4-phenacylidene-1,4-dihydropyridines. The bisiminium salt, N,N,N',N' -tetramethyI-N,N'-[2-(2,6-diphenyl-4H-pyran-4-ylidene)-1,3-propanediylidene]bis(iminium perchlorate) ( 2 ), reacts with ammonia to give 3,6-diphenylcopyrine and with primary amines to give the corresponding N,N' -dialkyl quaternary copyrines. The salt 2 reacts with secondary amines with exchange of the dimethylamino groups of 2 by the secondary arnine and addition of the amine at the 2-position of the pyran ring.     

Synthesis of pyridyloxadiazoles 1. Characterization and thermal rearrangement of an unexpected 1,2,4-oxadiazol-5(4H)one

The synthesis of pyridyloxadiazoles by the reaction of acid chlorides with 5-(2-pyrklyl)-tetrazole or 2-pyridineamidoxime was studied. Reaction of 2-pyridineamidoxime with N,N-dimethylcarbamyl chloride produced 3-(2-pyridyl)-4-N,N-dimethylaminocarbony 1-1,2,4-oxadi-azol-5(4H)one instead of the expected oxadiazole. The oxadiazolone underwent thermal rearrangement with expulsion of carbon dioxide to yield the desired 3-(2-pyridyl)-5-N,N-dimethylamino-1,2,4-oxadiazole.     

钯和四齿膦配体催化剂应用于Heck反应的研究

设计合成了以联萘二胺为骨架的四齿膦配体N,N,N',N'-四(二苯基膦甲基)-(1,1'-联萘)-2,2'-二胺,并将其与钯组成的催化体系用于苯乙烯和芳卤的Heck反应,该催化体系对各种卤代芳烃都表现出了很高的催化活性.对活化底物对溴苯腈,即使底物与催化剂的物质的量比达到10 000,反应20 h几乎能达到定量转化;该催化体系对活性更低的杂环底物也取得了良好的催化效果.     

Investigation of the preparation of pyrimidine isocyanates

Uracil-5-yl isocyanate and 1,3-dimethyluracil-5-yl isocyanate were prepared from the corresponding new carboazides. 1,3-Dimethyluracil-5-ylmethyl isocyanate obtained from the chloro compound and silver cyanate, was polymerized with an anionic initiator to the cyclic trimer. Attempts to isolate uracil-6-yl isocyanate, 1,3-dimethyluracil-6-yl isocyanate, pyrimidinyl-4-isocyanate, and 2,6-dichloropyrimidinyl-4-isocyanate were unsuccessful. Ethyl carbamate derivatives were made from all new azides and isocyanates. Other new pyrimidine derivatives included N,N'-bis(pyrimidine-4-carbonyl)hydrazine, N,N'-bis(1,3-dimethyluracil-5-yl)urea, N,N'-bis(1,3-dimethyluracil-6-yl)urea and N,N'-bis(2,5,6-trichloro-4-pyrimidinyl)oxamide.     

脱铁伴清蛋白两结合位点不同酪氨酸氢键的特性

The interaction of gallium（Ⅲ） with the ligands containing phenolic group（s）, such as salicylic acid, 8-hydroxyquinoline, N,N＇-bis（2-hydroxybenzyl）ethylenediamine-N,N＇diacetic acid （HBED）, N,N＇-ethylenebis[2-（o- hydroxyphenyl）glycine （EHPG）, and ovotransferrin, was studied, respectively, by means of fluorescence in 0.01 mol/L Hepes at pH 7.4 and room temperature. Fluorescence intensity showed an increase when gallium（Ⅲ） was bound to 8-hydroxyquinoline and HBED. In contrast, it was decreased with the interaction of gallium（Ⅲ） with salicylic acid and EHPG. At pH 7.4, there was N…H-O type intramolecular hydrogen bond in the former, and the latter existed O…H-O type intramolecular hydrogen bond. Fluorescence titration of apoovotransferrin with gallium（Ⅲ） displayed that the fluorescence intensity was decreased at the N-terminal binding site, while enhanced at the C-terminal binding site. It can account for the O…H-O type intramolecular hydrogen bonds for the phenolic groups of Tyr92 and Tyr191 residues at the N-terminal binding site. And there are N…H-O type intramolecular hydrogen bonds for Tyr431 and Tyr524 residues at the C-terminal binding site. In addition, under the same conditions, the conditional binding constant of gallium（Ⅲ） with EHPG or HBED determined by fluorescence method is lg KGa-EHPG=19.18 or lg KGa-HBED= 19.08.