Photochemistry of Hantzsch 1,4-dihydropyridines and pyridines

The photochemistry of some Hantzsch 4-phenyl-1,4-dihydropyridines bearing a substituent on the phenyl ring (the three isomeric chloro derivatives and the 4′-nitro derivative) has been studied. All of these compounds underwent inefficient aromatization to the corresponding pyridines (quantum yield <10⁻⁴ at 366 nm, <10⁻² at 254 nm). This process is scarcely affected by molecular oxygen and is initiated by proton transfer (from C₄-H), probably to the solvent, from the excited singlet. In turn, the thus formed pyridines were photoreactive with comparable or higher efficiency. Thus, the 4-(3′-chlorophenyl) and 4-(4′-chlorophenyl) Hantzsch pyridines underwent positional rearrangement to form two isomers each. The reaction occurs via Dewar benzene--prismane path. In the case of the minor isomer a further 1,3-shift take place at the Dewar benzene level. The 4-(2′-chlorophenyl) derivative underwent C-Cl bond homolysis, which led to cyclization of the phenyl group onto one of the ester groups forming a pyrane ring.     

Studies on the syntheses of azole derivatives. Part VII. Syntheses of 1 -phenyl-Δ2-1,2,4-triazolin-5-one derivatives [studies on the syntheses of heteroeyclic compounds. CD XI]

Bromination of 3-methyl-1-phenyl-Δ²-1,2,3-lriazolin-5-one (II) and its 4-phenyl derivative III afforded the corresponding I-(p-Bromophenyl) derivatives IV and V, respectively. (Chlorination of the 4-phenyl derivative III gave I-(P-chlorophenyl) derivative VI. In addition, 3-N-subsuituted-carhamoyl-1,2,4-triazolin-5-ones(XII, XIII, and XIV) were synthesized by the Schotten-Baumann reaction of 3-carboxy-1-phenyl-Δ²-1,2,4-triazolin-5-one (XI) with various amines.     

Synthesis of some new nitrogen bridge-head pyrido[1,2,4]triazepines

Ring closure reactions of 1,6-diamino-4-(4-chlorophenyl)-2-oxopyridine-3,5-dicarbonitrile with various 1,3-dielectrophiles, namely, diethyl malonate, ethyl ethoxymethylenecyanoacetate, 2-cyano-3,3-bis(methylthio)acrylonitrile, dimethyl acetylenedicarboxylate, dehydroacetic acid, chromone-3-carbonitrile, and 3-formylchromone led to the formation of the target biheterocyclic 1,2,4-triaze-pines. The reactions with 3-phenylazo-2,4-pentadione, ethyl α-cyano-α-phenylazoacetate, and 3,1-benz-oxazin-4-one derivative are also described.     

Special features of the alkylation of 7-bromo-5-(2-chlorophenyl)- 3-hydroxy-1,2-dihydro-3h-1,4-benzo- diazepin-2-one with alkyl tosylates

On interacting 7-bromo-5-(2-chlorophenyl)-3-hydroxy-1,2-dihydro-3H-1,4-benzodiazepin-2-one with methyl, hexyl, dodecyl, and cetyl tosylates, 1-alkyl-7-bromo-5-(2-chlorophenyl)-1,2,4,5-tetrahydro-3H-1,4-benzodiazepin-2,3-diones, and 1-alkyl-7-bromo-5-(2-chlorophenyl)-3-hydroxy-1,2-dihydro-3H-1,4-benzodiazepin- 2-ones were obtained. Only the dione was formed in the case of hexyl tosylate. On alkylating with methyl tosylate only the 3-hydroxy derivative was formed. It was shown that at pH 14 the 1-cetyl and 1-dodecyl-3-hydroxy derivatives were completely converted into the corresponding diones. The molecular and crystal structures of the compounds were established by X-ray structural analysis.     

Reaction of 3-(o-chlorobenzylidene)-2,4-dioxopentanoic acid with hydroxylamine hydrochloride. Revised structure tor azeto[3,2-d]isoxazoline

Reaction of 3-(o-ehlorobenzylidene)-2,4-dioxopentanoic acid (1) with hydroxylamine hydro-chloride in acetic acid gave 5-(o-chlorophenyl)-3-methyl-4-(α-hydroxyimino)isoxazolineglyo-xylic acid (5) and 3-(o-chlorobenzylidene)-4-hydroxyimino-2-oxopentanoic acid (2) in 57% and 7% yields. Pyrolysis of 5 afforded 5-(o-chlorophenyl)-3-methylisoxazole-4-carbonitrile (8), cis- and trans-5-(o-chlorophenyl)-3-methylisoxazoline-4-carbonitriles (9,10), and 5-(o-chloro-phenyl)-3-methylisoxazoline-4-carboxamide (11).     

Efficient Catalytic and Thermal Syntheses of Novel Thiadiazole,Triazole, Benzothiazole,and Fused Quinazoline Derivatives

Russian Journal of Organic Chemistry - A thiourea derivative, 4-chloro-N-[(4-chlorophenyl)carbamothioyl]benzamide, was oxidized with iodine in acetic acid to give the corresponding disulfide,...     

Synthese der diastereomeren 4-Amino- und 4-Hydroxy-3-(p-chlorphenyl)-valeriansäuren. Kristallstruktur von cis-4-(p-bromphenyl)-5-methyl-2-pyrrolidinon

Synthesis of 4-amino- and 4-hydroxy-3-(p-chlorophenyl)-valeric acids. X-ray structure of cis-4-(p-bromophenyl)-5-methyl-2-pyrrolidinone The syntheses of diastereomeric 4-amino- and 4-hydroxy-3-(p-chlorophenyl)-valeric acids and of their ring closure products (lactones and lactams), starting from 3-(p-chlorophenyl)-4-oxo-valeric acid, are described. A single-crystal X-ray structure analysis of cis-4-(p-bromophenyl)-5-methyl-2-pyrrolidinone is given. Some aspects of the biochemistry of threo-3-(p-chlorophenyl)-4-amino-valeric acid are presented.     

Synthesis and utilisation of 2,7′-diindolylmethanes and a 2-(2-indolyl)pyrrolylmethane as macrocyclic precursors

Treatment of 3-(4-chlorophenyl)-7-hydroxymethyl-4,6-dimethoxyindole with 3-(4-chlorophenyl)-4,6-dimethoxyindole results in the generation of two geometrically isomeric diindolylmethanes in addition to a novel triindolyl oligomer, which has been structurally characterised. The 2,7′-diindolylmethanes were found to be unstable under Vilsmeier formylation conditions, thus hampering macrocyle precursor construction. In an alternate approach, the 3-(4-chlorophenyl)-4,6-dimethoxyindole-7-carbaldehyde was converted into the indolyl-pyrrolyl macrocycle precursor 5-(3-(4-chlorophenyl)-4,6-dimethoxyindole-2-ylmethyl)-4-ethyl-3-methylpyrrole-2,7-dicarbaldehyde, which was used to generate an unsymmetrical pentaaza macrocycle.     

An effective BINAP and microwave accelerated palladium-catalyzed amination of 1-chloroisoquinolines in the synthesis of new 1,3-disubstituted isoquinolines

A facile and microwave accelerated reaction of 1-chloro-3-(4-chlorophenyl)isoquinoline with various heterocyclic amines, catalyzed by Pd, in the presence of BINAP additive and sodium carbonate as the base, leads to the formation of 3-(4-chlorophenyl)-1-(1H-1,2,3-triazol-1-yl)isoquinoline, 3-(4-chlorophenyl)-1-(1H-imidazol-1-yl)isoquinoline and 3-(4-chlorophenyl)-1-(1H-1,2,4-triazol-1-yl)isoquinoline via Buchwald protocol in good yields. Similarly pyrazolylisoquinolines are also reported.     

间氯苯基锰卟啉-5-氟尿嘧啶配合物的合成及其对癌细胞的抑制活性

合成了4种新5-氟尿嘧啶-卟啉衍生物：5-[3-(2-(5-氟尿嘧啶-1-基)乙氧基)苯基]-10,15,20-三(3-氯苯基)卟啉(1a)、5-[3-(2-(5-氟尿嘧啶-1-基)乙氧基)苯基]- 10,15,20-三(3-氯苯基)锰卟啉(2a)、5-[3-(3-(5-氟尿嘧啶-1-基)丙氧基)苯基]-10,15,20-三(3-氯苯基)锰卟啉(2b)和5-[3-(4-(5-氟尿嘧啶-1-基)丁氧基)苯基]-10,15,20-三(3-氯苯基)锰卟啉(2c),通过UV-Vis、IR、MS及元素分析表征了它们的结构。 用噻唑蓝法（MTT法）测定了化合物2a、2b和2c对人胃癌细胞株BGC-823的抑制活性。 化合物2b的半数抑制浓度IC50为1.34 μmol/L,表明有一定的细胞毒作用。     

Synthesis of side-chain monofluorinated amphetamines

R- and S-2-Amino-3-fluoro-1-phenylprupane were prepared in approximately 50% yields by the action of HF-pyridine on R- and S-2-benzylaziridine. (±)-2-Amino-3-fluoro-1-(4-chlorophenyl)propane was similarly prepared from (±)-2-(4-chlorobenzyl)aziridine. Structures of products were confirmed by n.m.r. and mass spectroscopy. In contrast, when 2-benzyl-N-tosylaziridine was reacted with HF in pyridine, the C₂ atom of the aziridine ring was the site of fluorination and the N-tosylated derivative of 3-amino-2-fluoro-1-phenylpropane was obtained in excellent yield.     

Synthesis and Crystal Structure of N-[1-(4-Chlorophenyl)- 1,4-dihydro-4-oxe-6-methylpyridazine-3-carbonyl]- N'-benzoylhydrazine

1 INTRODUCTION Pyridazinone derivatives represent one of the most active classes of compounds possessing a wide spectrum of biological activity. It was widely used in pharmaceuticals and agrochemicals[1, 2]. Rohm Haas Company had reported that pyridazinones exhibit useful plant growth regulating effects [3,4]. It was also reported that diacylhydrazines exhibit excellent insecticides [5~7]. In view of these facts, it was contemplated to synthesize compounds con- taining both pyridazinone …     

Kinetic study on the acidic hydrolysis of lorazepam by a zero-crossing first-order derivative UV-spectrophotometric technique

A zero-crossing first-order derivative UV-spectrophotometric technique for monitoring the main degradation product, 6-chloro-4-(2-chlorophenyl)-2-quinazoline carboxaldehyde, was developed to study the acidic hydrolysis of lorazepam in hydrochloric acid solutions of 0.1 M. Due to the complete overlap of the spectral bands of the parent drug and the hydrolysis product (the range between their spectral maxima was only 3 nm), the graphical methods of derivative spectrophotometry were not efficient. The relative standard deviation of the proposed technique was less than 2.4% and the detection limit was 6.6x10(-8) M. Accelerated studies at higher temperatures have been employed that enable rapid prediction of the long-term stability of this drug. Pseudo-first order reaction kinetics was observed. Kinetic parameters, k(obs) and t(1/2), were calculated, which were similar to those estimated by an HPLC method developed in our laboratory.     

Synthesis and anti-inflammatory properties of novel 1,2,4-triazole derivatives

This research is based on the pharmacological activity of the triazole ring. In the last decade much work has been conducted on the triazole ring. Scientists have developed many new compounds based on this structure and screened them to obtain molecules with good pharmacological activity. In this research starting from 4-amino-5-(4-chlorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione, a series of new 1,2,4-triazole derivatives were prepared. Results revealed that two compounds had anti-inflammatory potency after 4 h greater than that of indomethacin whereas another derivative had less potency than indomethacin.     

Synthesis of potential impurities of cloxacillin sodium drug substance

The present work describes the synthesis and characterization of six related compounds of cloxacillin sodium ( 1 ) viz penicilloic acid of cloxacillin (2) , (3-(2-chlorophenyl)-5-methylisoxazole-4-carbonyl) glycine (Glycine analogue of cloxacillin) (3), CMICAA adduct of cloxacillin (4) , (4S)-2-(carboxy(3-(2-chlorophenyl)-5-methylisoxazole-4-carboxamido) methyl)-3-(2-ethylhexanoyl)-5,5-dimethylthiazolidine-4-carboxylic acid (N-2-ethylhexanoyl penicilloic acid of cloxacillin) ( 5 ), N-Acetylated penicilloic acid of cloxacillin ( 6 ), and Cloxacillin Penicillamide (7) . These related compounds are very essential in the process development of cloxacillin sodium and are used as reference standards to determine the quality of the drug substance.     

Hydrophobic vitamin B12. Part 19: electroorganic reaction of DDT mediated by hydrophobic vitamin B12

The controlled-potential electrolysis of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) was carried out at -1.4 V vs. Ag-AgCl in the presence of a hydrophobic vitamin B12, heptamethyl cobyrinate perchlorate. DDT was dechlorinated to form 1,1-bis(4-chlorophenyl)-2,2-dichloroethane (DDD), 1,1-bis(4-chlorophenyl)-2,2-dichloroethylene (DDE), 1-chloro-2,2-bis(4-chlorophenyl)ethylene (DDMU) and 1,1,4,4-tetrakis(4-chlorophenyl)-2,3-dichloro-2-butene (TTDB)(E/Z), and quantitative recovery of the catalyst after the electrolysis was confirmed by electronic spectroscopy. A photo-sensitive intermediate having a cobalt-carbon bond formed during the electrolysis was characterized by electronic spectroscopy. A mechanism for the formation of various dechlorinated products was investigated by using deuterium solvents and various spectroscopic measurements such as UV-VIS and the EPR spin-trapping technique.     

Structure and reactivity of 3- and 4-[(4′-chlorophenyl)sulfamoyl]-1-diazoalkan-2-ones

Conclusions Under the conditions of the acidic cyclization reaction of homologous 3- and 4-[(4-chlorophenyl)sulfamoyl]-1-diazoalkan-2-ones, the formation of the five-membered heterocycle, a pyrrolidin-3-one derivative, is more convenient than the formation of the four-membered heterocycle- an azetidin-3-one derivative. These results are in agreement with the differences in conformations of diazoalkane molecules in the crystalline state.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 134–138, January, 1986.     

The synthesis of 1-alkyl-4a-(4-chlorophenyl)- 4,4a-dihydropyrimido[6,1-a]isoindol-9(3H)-one

The primary amino group of 3-(2-aminoethyl)-3-(4-chlorophenyl)-2,3-dihydro-1H-isoindol-1-one ( 1 ) was acylated with acetyl chloride, benzoyl chloride and phenyl acetyl chloride to form the amides 2a -c, respectively. These were cyclized in phosphorus oxychloride to give the 1-substituted-4a-(4-chlorophenyl)-4,4a-dihydropyrimido [6,1-a]isoindol-9(3H)-ones 3a-c . Heating of 1 in formic acid lead to the formation of 4a-(4-chlorophenyl)-4,4a-dihydropyrimido[6,1-a]isoindol-9(3H) -one (3d) . Heating of 1 in the presence of phosgene lead to the formation of 4a-(4-chlorophenyl)-2,3,4,4a-tetrahydropyrimido[6,1-a]isoindole-1, 9-dione (4).     

A short and convenient chemoenzymatic synthesis of both enantiomers of 3-phenylGABA and 3-(4-chlorophenyl)GABA (Baclofen)

Both enantiomers of the pharmacologically active GABA analogues 4-amino-3-phenyl and 4-amino-3-(4-chlorophenyl)butyric acid (Baclofen) with high enantiomeric excesses were synthesized by a chemoenzymatic method involving α-chymotrypsin mediated kinetic resolutions of the corresponding 3-phenyl- and 3-(4-chlorophenyl)-4-nitrobutyric acid methyl ester precursors.     

Unusual michael reaction of 3-(4-Chlorophenyl)-1-phenylprop-2-en-1-one with 3-amino-N-phenyl-3-thioxopropanamide

3-(4-Chlorophenyl)-1-phenylprop-2-en-1-one reacted with 3-amino-N-phenyl-3-thioxopropanamide under basic conditions in ethanol to give a mixture of 3-(4-chlorophenyl)-2-cyano-5-oxo-N,5-diphenylpentanamide and 3-(4-chlorophenyl)-1,5-diphenylpentane-1,5-dione. The structure of the former was determined by X-ray analysis. The reaction of the same compounds in DMSO in the presence of sodium hydroxide produced 4-(4-chlorophenyl)-N,6-diphenyl-2-thioxo-1,2,3,4-tetrahydropyridine-3-carboxamide.