Reactions ofβ, β-dichlorovinyl organyl sulfides with thiols and the synthesis of bis(organylthio)acetylenes

Conclusions ,-Dichlorovinyl organyl sulfides can react with thiols and KOH by several pathways, depending on the conditions, leading to different unsaturated sulfides. We have found a simple preparative route to bis(alkylthio)acetylenes with identical or different radicals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 426–431, February, 1978.We thank V. V. Keiko for the preparative separation of isomers (I) and (III).     

Cleavage of α,Β- and Β,υ-mono- and diunsaturated organyl alkenyl sulfides by trialkyl- and trialkoxysilanes

Conclusions Organyl alkenyl sulfides of general formula RS(CH₂)nCH=CH₂ react with triethyl- and triethoxysilane in the presence of PdCl₂(C₆H₅CN)₂ and P(C₆H₅)₃, with cleavage of the S-C bond and the formation of the corresponding Si-substituted organylthiosilanes RSSiR₃' and disilthianes R₃'SiSSiR₃'. The reaction is accompanied by the disproportionation of the starting silanes R₃'SiH with the formation of R₄'Si. Hydrosilylation products were not detected.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 170–173, January, 1981.     

Syntheses of Cyclopropyl Silyl Ketones

The synthesis of the cyclopropyl silyl ketones 1 – 4 is described. The trimethylsilyl ketone 1 was prepared from geraniol ((E)- 5 ) in ca. 10% overall yield by cyclopropanation leading to 6 , CrO₃ oxidation to the aldehyde 8 , reaction of the latter with trimethylsilyl anion to 14A + B , and CrO₃ oxidation to 1 . Also for the (t-butyl)dimethylsilyl ketones 2 – 4 , an efficient four-step synthesis with overall yields of 48%, 85%, and 13%, respectively, was elaborated, starting from the allylic alcohols (E)- 5 , and 23 . The method of preparation involves as the key step a Wittig rearrangement of the silylallyl ethers ((E/Z)- 20 , 24 ) to the silyl alcohols ((E/Z)- 21 , 25 ), subsequent cyclopropanation ( 19A + B , 22A + B , 26 ), and oxidation to the cyclopropyl silyl ketones 2 – 4 .     

Synthesis of Cyclopropyl Ethers and Cyclopropanols by Carbene Transfer – Acetolysis of Cyclopropyl p-Toluenesulfonates

The reaction of chloromethyl phenyl ether with butyllithium in olefins yields phenoxy-cyclopropanes. 1-Chloro-1-phenoxycyclopropanes can be prepared in a similar manner, though the yields are poor. Alkoxycyclopropanes are formed when dichloromethyl alkyl ethers are treated with methyllithium/lithium iodide in the presence of olefins. Cyclopropanols can be obtained in good yields by reaction of (β-chloroethoxy)cyclopropanes either with butyl- or ethyllithium or with bases. – As was shown by acetolysis experiments with cyclopropyl p-toluenesulfonates having a known steric configuration, the rearrangement of a cyclopropyl derivative into an allyl cation proceeds in accordance with the Woodward-Hoffmann-DePuy rule. The solvolysis of exo-bicyclo[n.1.0]alkyl p-toluene-sulfonates is assumed to proceed via “semi-open” intermediates, which are somewhere between an allyl cation and a cyclopropyl cation.     

Photo-Trifluoromethylthiolation of Cyclopropyl Phenyl Propargyl Alcohol

Seven compounds are formed in various amounts when a solution of cyclopropopyl phenyl propargyl alcohol and trifluoromethylsulfenyl chloride in acetonitrile is exposed to UV light. The probable mechanism of formation and the mass spectral characterization of these compounds are described.     

Calixrotanes: Calixarenes Incorporating Spiro-Linked Cyclopropyl Groups

Macrocyclic compounds (calix[4]- and calix[6]arene derivatives) with aryl rings interconnected by spirocyclopropyl groups have been synthesized and structurally characterized. The compounds were prepared by the reaction of dichlorocarbene with calixarenes possessing exocyclic double bonds at the bridges, followed by reductive perdechlorination of the spirocyclopropyl groups. In all systems, pairs of geminal rings connected to the quaternary spiro carbon atoms are oriented anti, and the methylene groups of the cyclopropyl rings are located in isoclinal positions. Calix[6]rotane adopts in the crystal and in solution a 1,3,5-alternate conformation. The presence of the spirocyclopropyl groups increases the rigidity of the macrocyclic ring.     

Photochemical Synthesis of Highly Functionalized Cyclopropyl Ketones

A series of di‐ and trisubstituted cyclopropyl ketones 11 were prepared by irradiation of ketones 3 and 5 , which bear a leaving group adjacent to the carbonyl C‐atom. The required ketones 3 could be easily synthesized either by functionalization of ketones 1 with a hypervalent iodine reagent, 2 , or by O‐sulfonylation of α‐hydroxy ketones 7 . The nitrates 5 were obtained by treatment of the corresponding α‐bromo ketones with AgNO₃. The irradiation of 3 and 5 must be performed in the presence of an acid scavenger (1‐methyl‐1H‐imidazole) to obtain the cyclopropanes 11 in good yields. The synthetic efficiency of the method was, among other things, demonstrated by the preparation of a highly strained bicyclo[2.1.0]pentane 11i in good yield. The mechanism of the photochemical cyclization was investigated by means of photokinetic measurements, as well as by quantum‐chemical calculations. It was shown that the presence of the leaving group substantially influences all steps of the photochemical reaction cascade. The X‐ray crystal structures of 11j and exo‐ 11k were also determined.     

Thermal reactions of organyl chalcogenides with α,β-unsaturated aldehydes

Thermal gas-phase reactions of acrolein, cinnamaldehyde, and benzaldehyde with diorganyl chalcogenides and diorganyl dichalcogenides were studied. Acrolein does not react with chalcogenides at 300–600°C but completely decomposes under reaction conditions. At 600–650°C, cinnamaldehyde reacts only with diorganyl selenides and diselenides to give benzoselenophene. Its highest yield (53%) is achieved in the reaction with dimethyl diselenide at 630°C and at an equimolar ratio of the reactant. The gas-phase reactions of benzaldehyde at 400–500°C afford chalcogen-containing derivatives of several types, among which thioanisole and its selenium or tellurium analogs predominate. The mechanisms of the above reactions were discussed in terms of homolytic substitution of the formyl group at unsaturated carbon atoms by chalcogenyl radicals.     

含环丙基结构的药物研究进展

环丙基的化学结构不同于直链脂肪烃和其他多元脂肪环,在药物分子的设计中经常被使用,具有增强药物的药效、增强代谢稳定性、降低脱靶作用、增强对受体的亲和力、限制多肽的水解作用、增加血脑屏障渗透率、降低血浆清除率以及改善药物的解离度(pK_a)等功效。含有环丙基结构的药物被开发用于治疗呼吸系统疾病、精神障碍类疾病、内分泌和代谢系统疾病、感染性疾病、神经系统疾病、心脑血管疾病以及肿瘤等。本文将对含有环丙基结构药物的研究进展进行综述。     

Synthesis of unsaturated organochalcogen compounds proceeding from dichloroethenes and organyl dichalcogenides

Reaction of 1,1- and 1,2-dichloroethenes with Ph₂S₂, Ph₂Se₂, Bn₂S₂, and i-Pr₂S₂ in a system hydrazine hydrate–KOH proceeds as a sequence of successive transformations: dehydrochlorination of initial dichloroethenes to form chloroacetylene, chlorine substitution for the chalcogen-containing nucleophile (ethynylchalcogenides formation), and the addition of the nucleophilic reagent to the triple bond affording 1,2- dichalcogenylethenes. In reactions with PhS^– and PhSe^? nucleophiles due to the high rate of all stages 1,2-bis (phenylchalcogenyl)ethenes are obtained having mainly the Z-configuration. In reactions with BnS^? and i-PrS^? in the IR, NMR and chromato-mass spectra intermediate ethynylchalcogenides were identified, and the final products consisted of a mixture with the prevalence of the Z-isomer.     

Microwave-Assisted N-Cyclopropylation of Pyridinols with Cyclopropyl Boronic Acid

Copper(II)-mediated N-cyclopropylation of pyridinols involving copper(II) acetate, pyridine, and NaHMDS under microwave conditions in a dry air atmosphere is described.     

Cyclopropyl carbinol rearrangement for benzo-fused nitrogen ring synthesis

A synthetic method that relies on gold-catalysed cyclopropyl carbinol rearrangement of 2-tosylaminophenyl cyclopropylmethanols to prepare 2,3-dihydro-1H-benzo[b]azepines and 2-vinylindolines efficiently is reported. The reactions were shown to be chemoselective, with secondary and tertiary alcohol substrates exclusively providing benzo-fused five- and seven-membered ring products, respectively. The ring-forming process was also found to proceed in moderate to excellent yields under mild conditions only in the presence of the gold and silver catalyst combination. The mechanism is thought to involve activation of the alcohol by the (p-CF(3)C(6)H(4))(3)PAuCl/AgOTf (Tf = triflate) catalyst, resulting in ionization of the starting material. The tertiary carbocationic intermediate generated in situ in this manner then triggers ring-opening of the cyclopropane moiety and trapping by the tethered aniline group to give the 2,3-dihydro-1H-benzo[b]azepine. Cyclopropane ring fragmentation of the secondary carbocationic analogue, on the other hand, results in diene formation followed by subsequent intramolecular hydroamination to afford the 2-vinylindoline.