Isothiazoles IX. Halogenation of 2-substituted-4-isothiazolin-3-ones

Bromination of 4-isothiazolin-3-ones, I, gave the 4-bromo derivatives, III, in good yields, while formation of 4,5-dibromo derivatives, IV, was much more difficult. In contrast, chlorination of I, even under mild conditions, gave primarily 4,5-dichloro derivatives, VI, and lesser amounts of the 4-chloro derivatives, V. Vigorous bromination of the 4-methyl analog of I gave the 5-bromo derivatives, VIII, whereas mild chlorination gave predominantly the 4,5,5-trichloro derivatives, X.     

Kinetics of hematite chlorination with Cl2 and Cl2 + O2: Part I. Chlorination with Cl2

Preliminary tests of the chlorination of two iron oxides (wüstite and hematite) in various chlorinating gas mixtures were performed by thermogravimetric analysis (TGA) under non-isothermal conditions. Wüstite started to react with chlorine from about 200 °C generating ferric chloride and hematite as the final reaction products. The presence of a reducing and oxidizing agent in the chlorinating gas mixtures influenced the chlorination reactions of both iron oxides, during non-isothermal treatment, only at temperatures higher than 500 °C.The chlorination kinetics of hematite with Cl₂ have been studied in details between 600 and 1025 °C under isothermal chlorination. The values of the apparent activation energy (E_a) were about 180 and 75 kJ/mol in the temperature ranges of 600–875 and 875–1025 °C, respectively. The apparent reaction order with respect to Cl₂ was found to be 0.67 at 750 °C. Mathematical model fitting of the kinetics data was carried out to determine the most probable reaction mechanisms.     

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.     

Chlorination of 4-methyl-8-methoxy-2,3-dihydro-1H,1,5-benzodiazepin-2-one

The results of the chlorination of 4-methyl-8-methoxy-2,3-dihydro-1H,1,5-benzodiazepin-2-ones are compared with the results of quantum-chemical calculations of 4-methyl-2,3-dihydro-1H-1,5-benzodiazepin-2-ones with various substituents in the benzene ring in the case of homolytic halogenation. The chlorination of 4-methyl-8-methoxy-2,3-dihydro-1H-1,5-benzodiazepin-2-one (I) with N-chlorosuccinimide leads to 3-chloro- and 3,3-dichloro-4-methyl-8-methoxy-2,3-dihydro-1H-1,5-benzodiazepin-2-ones, whereas chlorination with sulfuryl chloride leads to 4-chloromethyl and 3,3-dichloro-4-methyl derivatives. The IR, PMR, and mass spectra of the synthesized compounds are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1272–1274, September, 1981.     

Pyrimidones. 2. Synthesis and reactions of 2-chloropyrimidines

The treatment of 1-alkyl-5-aryl and 1-alkyl-4,5-diaryl-2-(1H)pyrimidones with phosphorus oxychloride and phosphorus pentachloride resulted in chlorination and dealkylation to furnish 2-chloro-5-aryl (or 4,5-diaryl)-pyrimidines. These chlorpyrimidines were reacted with a variety of nitrogen, oxygen, sulfur, and carbon nucleophiles to produce the corresponding 2-substituted pyrimidines. In the case of phenyllithium, attack occurred at the 4-position of the pyrimidine ring yielding 11 . Triazolopyrimidine 9 was synthesized via the treatment of 2d with hydrazine followed by reaction with triethyl orthoformate.     

The structure of chlorinated poly(vinyl chloride). VI. Comparison of the chlorination of poly(vinyl chloride) and β,β-d2-poly(vinyl chloride) with 1H-NMR and 13C-NMR spectroscopy

Samples of chlorinated poly(vinyl chloride) (CPVC) and chlorinated β,β-dideuterated poly(vinyl chloride) (β,β-d₂-CPVC) were prepared under identical reaction conditions. The microstructure of CPVC and β,β-d₂-(CPVC) was characterized by a combination of ¹H-NMR, ¹³C-NMR spectroscopy, and analytically determined chlorine content. A difference was observed in the reaction rates of chlorination of PVC and β,β-d₂-PVC, and, in their thermal chlorination in solution, also in the structure of the chlorinated products. It was proved that in the chlorination of β,β-d₂-PVC a new chlorine atom can also enter the original? CHCl? group. The results are discussed from the standpoint of the chlorination mechanism.     

Structure of chlorinated poly(vinyl chloride). X. Conclusions on the chlorination mechanism

The chlorination of poly(vinyl chloride) (PVC) was investigated by using deuterated polymeric models of PVC, viz., α-deuterated PVC (α-d-PVC) and β,β-dideuterated PVC (β,β-d₂-PVC). The chlorinated samples of PVC, α-d-PVC, and β,β-d₂-PVC were examined by combining infrared (IR), ¹H-NMR, ¹³C-NMR, and mass spectroscopy. The results obtained were used in a study of the reaction mechanism of PVC chlorination. The selectivity of chlorination and the extent of the substitution and elimination-addition mechanism of chlorination are discussed with respect to the degree of chlorination and chlorination conditions.     

成黄成色剂2-十六烷氧基苯甲酰乙酰基-(2'-氯-5'-苯胺磺酰基)苯胺氯化产物的鉴识

Much work has been recorded in the literature concerning chlorination of photographic couplers. However, no detailed report can be found with the coupler of the structure 1. In this paper, the chlorination of 1 using SO2Cl2 in CHCl3 was shown to give the chlorination product 2. UV, IR, 1H NMR and MS of the chlorination product are compared with that of 1, and with those reported in the literature for benzoylacetanilide. Thermolysis of 2 gives a liquid fraction, HPLC shows one peak, which was identifield by 1H NMR and MS to be o-CH3COC6H4OCH2CHClC14H29. Elemental analyses as well as MS of its 2, 4-dinitrophenylhydrazone agree well with the structure assigned.     

1H-imidazo[4,5-b]pyrazines. III. 2-Thiols and derivatives

1H-Imidazo[4,5-b]pyrazine-2-thiols were prepared. Their chlorination, alkylation and cyclization reactions are discussed.     

Reactions of γ-Sultines with Electrophilic Reagents. 4. Chlorination of 5-(4-Methoxyphenyl)-3-phenyl-1,2-oxathiolane 2-Oxide

We have studied chlorination of 5-(4-methoxyphenyl)-3-phenyl-1,2-oxathiolane 2-oxide and we discuss possible mechanisms for this reaction.     

Heterogeneous reactions of polyethylene. II. Distortion of crystallites due to chlorination

The effect of heterogeneous chlorination of high-density polyethylene on its crystalline regions was investigated by NMR, x-ray diffraction, differential scanning calorimetry, and infrared spectroscopy. Crystallites remained inaccessible to attack by chlorine, even after extensive chlorination, however, their perfection was affected by extensive chlorination of the adjacent amorphous regions.     

Structure of chlorinated poly(vinyl chloride). IV. Chlorination of β,β-d2-poly(vinyl chloride) as model for determination of the mechanism of chlorination

Chlorinated β,β-dideuterated poly(vinyl chloride) (β,β-d₂-CPVC) was prepared by photochemical suspension chlorination in concentrated hydrochloric acid with chloroform as swelling agent, and thermally in tetrachloroethane solution. ¹H-NMR (nuclear magnetic resonance) spectra of β,β-d₂-CPVC were recorded. The content of deuterium was determined in combustion products of β,β-d₂-CPVC as the D₂O:(H₁D)₂O ratio by means of mass spectroscopy. Both in the photochemical suspension chlorination and in the thermal solution chlorination of β,β-d₂-PVC, a decrease of the concentration of ? CHCl? groups was observed. The differences in structure of the suspension chlorinated and solution chlorinated β,β-d₂-PVC were confirmed.     

Chlorination and ortho-acetoxylation of 2-arylbenzoxazoles

Efficient and facile catalytic protocols for chlorination and ligand-directed ortho-acetoxylation of 2-arylbenzoxazoles have been developed. The chlorination is not a ligand-directed ortho-functionalization, but an electrophilic substitution process in the benzo ring of the benzoxazole moiety. Meanwhile, the acetoxylation exhibited high regioselectivity for the substrates containing a meta-substituent and occurred at the less sterically hindered ortho-C-H bond of the directing group.     

2-甲基-1,5-苯并硫氮杂的基态和激发态反应的研究 I: 2-甲基-1,5-苯并硫氮杂-4(5H)-酮的卤化和亲核取代反应

2-甲基-1,5-苯并硫氮杂-4(5H)-酮(1a)与不同的氯化试剂-五氯化磷、三氯氧磷和氯化砜在不同的条件下氯化,可分别生成:2-甲基-4-氯-1,5-苯并硫氮杂(2a)、2-氯-4-甲基-1,5-苯并硫氮杂(3a)、2-二氯甲基苯并噻唑(5)、2-三氯甲基苯并噻唑(6)和2-甲基-1,5-苯并硫氮杂-4(5H)-酮盐酸盐(4).2-甲基-4-氯-1,5-苯并硫氮杂与醇钠反应生成相应的2-甲基-4-烷氧基-1,5-苯并硫氮杂外,还可以分离到它的2,4-异构体,2-烷氧基-4-甲基-1,5-苯并硫氮杂.产物的结构均经元素分析、红外光谱、^1H和^1^3C核磁共振谱和质谱鉴定.     

Synthesis of 1,2,3‐Triazole Substituted Isoxazoles via Copper (I) Catalyzed Cycloaddition

The synthesis of a series of 3,5‐disubstituted isoxazole‐4‐carboxylic esters containing N‐substituted 1,2,3‐triazoles ( V ) starting from various benzaldehydes ( I ) is reported. Benzaldehydes undergo oximation with hydroxylamine hydrosulfate. Later, chlorination followed by condensation with methylacetoacetate and the hydrolysis of the resulting ester afforded respective carboxylic acid ( II ), which on chlorination with PCl₅ gave the corresponding acid chlorides ( III ). The coraboxylic acid chlorides ( III ) on propargylation gave propargylic esters ( IV ) and these on click reaction gave the title compounds ( V ).     

2—氧代—3,5,7—三氯吲哚丁酸乙酯的结构分析

为研究吲哚丁酸类氯化物的生理活性，对吲哚丁酸进行酯化、氯化和水解。用高分辨率的质子磁共振谱、质谱和红外光谱、元素分析确证了吲哚丁酸乙酯氯化产物为化合物２－氧代－３，５，７－三氯吲哚丁酸乙酯，该化合物未见文献报道，提出了其生成的可能机理。     

3-氧杂-8-氮杂双环[3.2.1]辛烷盐酸盐的合成

以己二酸为初始原料,依次经酰氯化,溴代,苄胺环合,水解,还原,脱水环合,氢解脱苄和成盐等8步反应,合成了3-氧杂-8-氮杂双环[3.2.1]辛烷盐酸盐,总收率23%,纯度100%,其结构经1H NMR确证。     

Cyclopalladated Ferrocenylimine Catalyzed Chlorination of 2‐Arylbenzoxazoles

An efficient and facile protocol for palladacycle‐catalyzed chlorination of 2‐arylbenzoxazoles was developed. The results represent the first examples involving the palladacycle as the catalyst for such chlorination. This chlorination was not a ligand‐directed ortho‐C H activation, but an electrophilic substitution process at the para‐position of the nitrogen atom in the benzo ring of benzoxazole moiety, the regiochemistry of which had been confirmed by HMBC spectral analysis. The catalytic system could tolerate various halogen atoms, such as F, Cl and Br, affording the corresponding products in moderate to excellent yields.     

2-氨基-6-三氟甲基嘧啶衍生物的合成及表征

近几年,含嘧啶结构单元的高效低毒农药层出不穷,如用作杀菌剂的嘧啶胺类、嘧啶腺类及嘧啶丙烯酸酯类,除草剂有嘧啶磺酰脲类、嘧啶水杨酸类、酰基(硫)脲类及三唑并嘧啶磺酰脲类。将含氟基团引入杂环结构是新药创制的一个发展方向,     

Chlorinated polyethylene. II. Chlorine distribution on the polymer chains

The nature of substitution in a slurry-phase chlorination of high-density polyethylene was studied using NMR and IR spectroscopy. The ratios of γ (or greater) methylenes were obtained from the NMR at different chlorine levels and compared with the theoretically predicted values based on a statistical treatment for substitution polymers. The results indicted that, unlike chlorosulfonated polyethylene, chlorinated polyethylene shows a hindered-type substitution. Molecular weight of the parent polyethylene, the degree of chlorination and the degree of residual crystallinity of the samples have no bearing on the type of substitution.