CHLORINATION OF AROMATIC HALIDES WITH CHLOROSULFONIC ACID

Abstract

Chlorosulfonic acid–iodine mixture has been shown to chlorinate a number of aromatic halides under mild conditions. In reaction with p-dichlorobenzene, the maximum yield (82%) of hexachlorobenzene required 5 mol of chlorosulfonic acid and 2.5 mol of iodine. The yield of product increased with the amount of iodine present. A mechanism of chlorination is proposed involving iodine-catalysed homolytic decomposition of the intermediate sulfonyl chlorides followed by heterolytic chlorination by the evolved iodine monochloride.

The reaction of o-, m-, and p-dichlorobenzenes with chlorosulfonic acid has been investigated. o-Dichlorobenzene at 100° gave a good yield (85%) of 3,4,3′,4′-tetrachlorodiphenylsulfone although m and p-dichlorobenzenes gave only the expected sulfonyl chlorides. This difference arises from the lack of steric hindrance in the p-position of o-dichlorobenzene leading to facile sulfone formation.

This was confirmed by the observation that 3,4-dichlorobenzenesulfonyl chloride undergoes the Friedel–Crafts reaction with o-dichlorobenzene to give 3,4,3′,4′-tetrachlorodiphenylsulfone (60%), but m- and p-dichlorobenzenes did not give any appreciable amounts of the corresponding sulfones under identical conditions.     

Synthesis of 3-amino 1H-pyrazoles catalyzed by p-toluene sulphonic acid using polyethylene glycol-400 as an efficient and recyclable reaction medium

Abstract

An efficient synthesis of 3-amino 1H-pyrazoles is described. The reaction of β-keto nitriles with hydrazines in the presence of a catalytic amount of p-toluene sulphonic acid using polyethylene glycol-400 as an efficient and recyclable reaction medium afforded the corresponding 3-amino 1H pyrazoles excellent yields.     

REACTIONS OF ORGANOCADMIUM REAGENTS WITH SULFONYL HALIDES II. ACTION OF ARENESULFONYL CHLORIDES ON SELECTED DIARYLCADMIUM COMPOUNDS

Abstract

The reaction of diarylcadmium compounds with arenesulfonyl chlorides was explored. Five different diarylcadmium reagnets, diphenylcadmium, di-p-tolylcadmium, di-α-naphthyl-cadmium, dibenzylcadmium and di-p-anisylcadmium, were selected to interact with benzene-or p-toluenesulfonyl chlorides. Unlike acid chlorides which react with these reagents to form ketones in high yields, the sulfonyl chlorides gave sulfones in moderate to poor yields. Beside the sulfones, sulfinic acids, biaryls, and haloarenes were obtained in moderate to good yields. Only di-p-anisylcadmium gave poor yield of p,p'-dianisyl.

Possible pathways are suggested and discussed.     

Environment-friendly and solvent-free synthesis of symmetrical bis-imines under microwave irradiation

Abstract

A short library of symmetrical bis-imines has been constructed efficiently from the reaction between dialdehydes and mono amines or diamines and mono aldehydes under microwave irradiation catalyzed by p-toluenesulphonic acid. The methodology is associated with shorter reaction time, good yields and simple workup.     

对氯苄基锡酰腙配合物的合成、抗肿瘤活性及其与DNA相互作用

用二对氯苄基二氯化锡分别与对甲基苯甲酰肼缩苯甲酰甲酸及苯甲酰肼缩苯甲酰甲酸反应,合成了2个对氯苄基锡配合物(C1、C2),通过元素分析、IR、1H NMR、13C NMR、119Sn NMR、HRMS以及X射线单晶衍射等表征了配合物结构.测试了配合物C1、C2的热稳定性以及配合物对癌细胞NCI-H460、HepG2、M...     

THE SYNTHESIS,PHYSICAL, AND SPECTRAL PROPERTIES,AND SOME REACTIONS OF A NEW STABLE bis-α-LACTAM (AZIRIDINONE) WITH A TERPENE SKELETON

A synthesis of a new stable bis-α-lactam, cis-1,1′(p-menth-1,8-ylene) bis(3-tert-butyl-2-azirididone) (4), derived from p-menthane, is described. Complete spontaneous thermal decomposition required 1h of reflux in boiling n-decane (b.p. 174°C) and the products are 2,2-dimethylpropanal (pivalaldehyde) (6) and 1,8-diisocyano-p-menthane (7). Reaction with benzylamine yielded the unexpected bis-benzylamide (13a), while reaction with sodium methoxide gave the bis-α-amino acid ester (14).     

Iodine and Brønsted acid catalyzed C–C bond cleavage of 1,3-diketones for the acylation of amines

Abstract

A metal-free N-acylation method of anilines with 1,3-diketones has been developed, by using iodine and p-toluene sulfonic acid as the co-catalysts. The reaction can proceed in 1,4-dioxane at elevated temperature to produce the corresponding amides with 48–89% yields. Further, the gram-scale experiment was carried out under the standard conditions and the possible mechanism was proposed.     

Protolytic properties and complexation with copper(II) ions of some azo derivatives of β-arylaminopropionic acids

The azo coupling reaction of N-(2-carboxyethyl)anthranilic acid and N,N,N′,N′-tetrabis(2-carboxyethyl)-1,3-phenylenediamine with diazosulfanilic acid yielded the complexones sodium 4-N-(2-carboxyethyl)amino-5-carboxyazobenzene-4′-sulfonate (I) and 2,4-N,N,N′,N′-tetrabis(2-carboxyethyl)diaminoazobenzene-4′-sulfonic acid (II), respectively. The acidity constants of I and II (20°C, μ = 0.1M KCl) were determined to be as follows: for I, pK ₀₀ = 1.29 ± 0.13, pK ₀ = 2.92 ± 0.07, pK ₁ = 3.92 ± 0.05, pK ₂ = 5.16 ± 0.03; for II, pK ₀₀ = 2.35 ± 0.06, pK ₀ = 2.81 ± 0.09, pK ₁ = 3.21 ± 0.11, pK ₂ = 3.81 ± 0.09, pK ₃ = 4.34 ± 0.04, pK ₄ = 5.03 ± 0.06, pK ₅ = 6.67 ± 0.07. The electronic absorption spectra of I and II were measured, and acid-base equilibrium scheme for I and II in aqueous solutions were suggested. The complexation constants of I and II with copper(II) ions were determined to be logK _CuQ^I= 5.47 ± 0.06 and logK _CuQ^II= 5.72 ± 0.13 (20°C, μ = 0.1 M KCl).     

[1,3]Dioxolo[5,6][1]benzothieno[2,3-c]-quinolin-6(5H)-ones

Summary The reaction of 3,4-methylenedioxycinnamic acid (1) with thionyl chloride resulted in the formation of 7-chlorothieno[2,3-f]-1,3-benzodioxole-6-carbonyl chloride (2) and cinnamoyl chloride (3). Subsequent reaction of the former withp-substituted anilines led to the formation of 7-chloro-N-(p-substituted phenyl)-thieno[2,3-f]-1,3-benzodioxole-6-carboxamides (4a–c) which on photocyclization afforded 2-substituted [1,3]dioxolo[5,6][1]benzothieno[2,3-c]quinolin-6(5H)-ones (5a–c) in fairly good yields and high purity. The structures have been confirmed by IR,¹H NMR, and analytical methods.Accepted for presentation at the Hong Kong International Symposium on Heterocyclic Chemistry (August 13–16, 1995)     

系列双核稀土配合物的合成、晶体结构及光物理性质

本文采用水热法合成了4种双核稀土配合物[Y₂(p-MBA)₆(Phen)₂] (1)、[Y₂(p-ClBA)₆(Phen)₂] (2)、[Pr₂(BA)₆(Phen)₂](3)和[Pr₂(p-ClBA)₆(H₂O)₂(Phen)₂](4)[Phen=邻菲咯啉、p-MBA=对甲基苯甲酸、BA=苯甲酸、p-ClBA=对氯苯甲酸]。测定了4种配合物的单晶结构。4种配合物在结构和配位方式上有很多的相似之处,它们的晶体都属于三斜晶系,P1空间群。在分子中,每个稀土离子与1个邻菲咯啉分子螯合,2个稀土离子均以苯甲酸根或其衍生物为桥。但是,桥连配体的数目以及配体的配位方式不尽相同。配合物4中配位水分子与对氯苯甲酸根之间形成了氢键,氢键将双核配合物4连接成二维层状网络结构。对4种配合物的UV-Vis-NIR、IR和荧光性质进行了测定和对比分析。配合物1和2的荧光指认为LLCT和LMCT,而配合物3和4的荧光表现出LLCT与LMCT混合跃迁及Pr³⁺的特征发射。     

Cooxidation of anilides and oxalic acid by chromic acid: A one‐step,three‐electron oxidation

The chromic acid oxidation of a mixture of oxalic acid and anilides proceeds much faster than that of either of the two substrates alone. The oxidation kinetics of acetanilide, p‐methyl‐, p‐chloro‐, and p‐nitroacetanilides by Cr(VI) in the presence of oxalic acid in aqueous acetic acid medium follows first‐order, zero‐order, and second‐order dependence in [oxidant], [substrate], and in [oxalic acid], respectively, while the oxidation kinetics of benzanilide, p‐methyl‐, p‐chloro‐, and p‐nitrobenzanilides follow first order in [oxidant] and fractional order each in [substrate] and [oxalic acid] and yields corresponding azobenzenes and benzaldehydes in the case of benzanilide and substituted benzanilides as the main products of oxidation. Aluminium ions suppress the reaction. The intermediate is believed to be formed from the anilide and a chromic acid‐oxalic acid complex. In the proposed mechanism, the rate‐limiting step involves the direct reduction of Cr(VI) to Cr(III). © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 33: 21–28, 2001     

RESEARCH ON THE POLYCONDENSATION KINETICS OF ω-AMINO-ACIDS*

In our previous report, it was discovered that the polycondensation of 9-amino-nonanoic acid follows second order from the beginning up to the extent of reaction, p, around 99%, and after which the reaction changes rapidly to third order. In this paper, we wish to report that this change of the reaction order from second to third occurred also in the polycondensation of 6-aminocaproic acid and 11-amino-undecanoic acid. The transition region lay again at p around 99%. It may be concluded that this is a general rule in the polycondensation of the ω-amino-acids (monomers of the A—B type), and the controversial results that appeared in the literature may be cleared up by our experiments.     

A new alkaloid from Portulaca oleracea L. and its antiacetylcholinesterase activity

A new alkaloid, (10E, 12E)-9-ureidooctadeca-10, 12-dienoic acid, named oleraurea (1) and 10 known compounds, p-hydroxybenzaldehyde (2), p-hydroxybenzoic acid (3), p-hydroxyacetophenone (4), benzamide (5), (E)-p-coumaramide (6), (E)-ferulamide (7), soyalkaloid A (8), β-carboline-3-carboxylic acid (9), 2, 3, 4, 9-tetrahydro-1H-pyrido [3, 4-b] indole-3-carboxylic acid (10), (1S, 3S)-1-methyl-1, 2, 3, 4-tetrahydro-β-carboline-3-carboxylic acid (11) were obtained from Portulaca oleracea L., in which, compounds 4, 5, 8–11 were isolated from the plant for the first time. The structure of the compound 1 was identified using spectroscopic methods including 1D and 2D NMR, HR-ESI-TOF-MS. The compounds 1, 5–11 presented anticholinesterase activities, but the P. oleracea extract (POE) presented very low anticholinesterase activity.     

Negative influence of pKa on activation energy barrier: A case study for double proton transfer reaction in inorganic acid dimers

Strength of acid can be determined by means of pK_a value. Attempts have been made to find a relationship between pK_a and activation energy barrier for a double proton transfer (DPT) reaction in inorganic acid dimers. Negative influence of pK_a is observed on activation energy (E_a) which is contrary to the general convention of pK_a. Four different levels of theories with two different basis sets have been used to calculate the activation energy barrier of the DPT reaction in inorganic acid dimers. A model based on first and second order polynomial has been created to find the relationship between activation energy for DPT reaction. © 2018 Wiley Periodicals, Inc.     

Chemiluminescence determination of <Emphasis Type="Italic">o</Emphasis>-chlorobenzylidenemalonic acid dinitrile in extracts

A chemiluminescence method was developed for determining o-chlorobenzylidenemalonic acid dinitrile (o-CBMA DN) in extracts. The method is based on chemiluminescence developed in a strong alkaline solution upon the interaction between 3-aminophthalic hydrazide (luminol) with the superoxide radical formed in the reaction of atmospheric oxygen activated by hemin with the products of the alkaline hydrolysis of o-chlorobenzylidenemalonic acid dinitrile and with the products of their condensation with p-nitrobenzaldehyde. The luminescence intensity of luminol was proportional to the concentration of o-CBMA DN in the range 1 × 10⁻⁶−1 × 10⁻¹ mg/mL. The determination limit for o-CBMA DN was (1 ± 0.3) × 10⁻⁶ mg/mL (p = 95%, n = 5, RSD = 29%) at 293 K.     

N-BROMOSUCCINIMIDE-CATALYSED TRANSESTERIFICATION AND RACEMIZATION OF SULPHINATES

Abstract

Both aliphatic and aromatic sulphinates undergo transesterification reaction in the presence of N-bromosuccinimide. Isopropanolysis of optically active alkyl arenesulphinates was found to give racemic isopropyl arenesulphinates. The rate of racemization of optically active isopropyl p-toluenesulphinate was found to be first order with respect to both N-bromosuccinimide and isopropyl alcohol, suggesting that the reaction is a bimolecular nucleophilic substitution at the sulphur atom. The para electrodonating substituents in the aromatic ring accelerate slightly the rate of racemization. At the same time the rate of racemization was found to be retarded by the increase of steric requirements of the substituent at the sulphinyl sulphur atom suggesting that the initial formation of bromoxonium salt is the rate-determining step. Completely nonstereospecific isopropanolysis of optically active alkyl p-toluenesulphinates suggests that a sulphurane is formed as an intermediate in the exchange step of the reaction.     

In situ vinylindole synthesis: Diels–Alder reactions with N-phenylmaleimides, 1-tetralones and 4-chromanones to give annulated tetrahydrocarbazoles

Abstract

An acid-catalyzed condensation of indole 4 with 1-tetralones 5a–f formed a vinylindole which reacted in situ with N-phenylmaleimides 7a–g. This cascade of condensation and Diels–Alder reaction was performed in IPA (isopropyl alcohol) and in presence of p-TsOH (p-toluenesulfonic acid) at reflux to produce annulated tetrahydrocarbazoles 8a–g and 10a–e. Similarly, 9a–g were synthesized by substituting 4-chromanone 6 for 5a–f. The 1-tetralone derived products 8a–g and 10a–e were obtained in higher yields (19–79%) compared to 4-chromanone derived 9a–g (6–28%), likely due to additional side reactions in case of chromanones. To establish the structure and stereochemistry of products, the crystal structure of 10c was obtained, confirming endo-Diels–Alder addition.     

Asymmetric Direct Aldol Reactions Catalyzed by a Simple Chiral Primary Diamine–Br⊘nsted Acid Catalyst in/on Water

Abstract

The direct asymmetric aldol reaction catalyzed by the simple and commercially available chiral primary diamines, (1S,2S)-1,2-diphenylethane-1,2-diamine and (1R,2R)-1,2-diphenylethane-1,2-diamine, is presented. The catalyst system is a primary amine with Br?nsted acid–catalyzed direct aldol reaction of p-nitrobenzaldehyde and cyclohexanone with high chemo- and stereoselectivity on water, which furnishes the corresponding β-hydroxyketone with up to 94% ee.     

贫电子环丙烷衍生物与2-巯基苯骈噻唑的反应研究

贫电子环丙烷衍生物1以精制四氢呋喃为溶剂, 与2-巯基苯骈噻唑(2)封管加热反应, 得到产物3和4. 产物3经IR, MS, ¹H NMR, ¹³C NMR和元素分析等数据确定其结构为: (R)-β-取代-(R)-γ-(2-巯基)苯骈噻唑基-γ-对位取代苯基丁酸或(S)-β-取代-(S)-γ-(2-巯基)苯骈噻唑基-γ-对位取代苯基丁酸(3); 产物4通过IR, MS, ¹H NMR, ¹³C NMR, 2D-NOESY谱和元素分析等数据确定其结构为: 反式-β-取代-γ-对位取代苯基-3-丁烯酸(4). 对生成产物的机理也进行了推测.     

REACTION OF p-NITROPHENYL p-TOLUENESULFONATE WITH NUCLEOPHILIC REAGENTS IN AQUEOUS ETHANOL

Abstract

The rate of nucleophilic reaction of anions and amines with p-nitrophenyltosylate has been determined in a 41% w/w ethanol-water mixture at 25°. For weakly basic amines, the reaction is general base and general acid catalyzed. Aldoximates and thiophenolate show an enhanced nucleophilicity compared to phenolates of same basicity. The results are interpreted in terms of charge and frontier controlled reactions.