共查询到20条相似文献,搜索用时 15 毫秒
1.
XS Wu Y Chen MB Li MG Zhou SK Tian 《Journal of the American Chemical Society》2012,134(36):14694-14697
The NH(2) group in primary allylic amines was substituted directly by sulfinate salts with excellent regio- and stereoselectivities. In the presence of 0.1 mol % [Pd(allyl)Cl](2), 0.4 mol % 1,4-bis(diphenylphosphino)butane (dppb), and excess boric acid, a range of α-unbranched primary allylic amines were smoothly substituted with sodium sulfinates in an α-selective fashion to give structurally diverse allylic sulfones in good to excellent yields with exclusive E selectivity. Replacing dppb with 1,1'-bi-2-naphthol (BINOL) allowed unsymmetric α-chiral primary allylic amines to be transformed into the corresponding allylic sulfones in good to excellent yields with excellent retention of ee. Importantly, the reaction complements known asymmetric methods in substrate scope via its unique ability to provide α-chiral allylic sulfones with high optical purity starting from unsymmetric allylic electrophiles. 相似文献
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Martin C Sandrinelli F Perrio C Perrio S Lasne MC 《The Journal of organic chemistry》2006,71(1):210-214
[reaction: see text] Aromatic 11C-sulfones were synthesized by S alkylation of lithium arenesulfinates, which are readily available from the corresponding thiols by an oxaziridine-mediated oxidation reaction with [11C]alkyl iodides in THF/H2O (4:1) at 150 degrees C. The radiosyntheses, including purification by HPLC, were completed in an average of 35 min from the end of the bombardment with 55-76% overall radiochemical yields (decay corrected). The described procedure extends the range of accessible labeling methods. 相似文献
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Low-temperature lithium–iodine exchange between tert-butyllithium and the appropriate iodide has been used to generate 3-oxa-5-hexenyllithium and a variety of 4-oxa-5-hexenyllithiums. The 3-oxa system is inherently unstable and fragments via facile β-elimination to give the anion of allyl alcohol and ethylene. The 4-oxa-5-hexenyllithiums, in contrast, are stable at low temperatures but undergo novel isomerization upon warming to deliver the lithium salt of a 4-alken-1-ol in the formal equivalent of an unprecedented [1,4]-Wittig rearrangement. The rearrangement is most likely mediated by 5-exo-trig ring closure of the 4-oxa-5-hexenyllithium to a (2-tetrahydrofuranyl)methyllithium followed by rapid opening to the alkoxide. 相似文献
4.
N,N-Dimethylformamide () and N,N-dimethylpivalamide () react with carbonyl chloride isocyanate () in the presence of antimony pentachloride to afford the amino substituted 1-oxa-3-azabutatrienium hexachloroantimonates ,. An X-ray diffraction analysis of confirms the proposed structure. The heterocumulenes , react with aldehydes, ketones and tertiary carboxamides to give the amino substituted 2-azaallenium salts - in high yields. 相似文献
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F. S. Pashkovskii E. M. Shchukina M. G. Gribovskii F. A. Lakhvich 《Russian Journal of Organic Chemistry》2006,42(4):527-540
A number of new 10-oxa-13-aza, 11-oxa-13-aza, and 9-oxa-7-aza prostanoids belonging to the B series were synthesized on the basis of 3-acyl-and 3-(3-arylprop-2-enoyl)furan-2,4(3H,5H)-diones. The scheme of synthesis includes selective hydrogenation of the exocyclic carbonyl group and reduction of the conjugated double bond in the acyl fragment of 3-acyl-and 3-(3-arylprop-2-enoyl)furan-2,4(3H,5H)-diones to obtain 3-alkyl-and 3-(3-arylpropyl)furan-2,4(3H,5H)-diones, transformation of the latter into the corresponding regioisomeric enol ethers via regioselective O-alkylation, and treatment of the enol ethers with primary aliphatic amines. 相似文献
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Kojiro Uetani Yuta Watanabe Kentaro Abe Hiroyuki Yano 《Cellulose (London, England)》2014,21(3):1631-1639
The influence of bulk density and drying method on pyrolysis behavior was studied by focusing on the salt content within the nanocellulose (NC) materials. The thermogravimetric curves for NC materials were found to be almost identical between the different bulk densities via the various drying methods. It was therefore concluded that the bulk density and drying method of NC materials had little influence on pyrolysis behavior. By quantitating the remaining salt content within the sulfate-introduced cellulose nanocrystal materials, we discriminated between the sulfate groups bonded onto cellulose and precipitated sulfate from the solvent. The precipitated sulfate was found to accelerate the pyrolysis of NCs in common with the bonded sulfate groups, but in a different rate. These two types of sulfate within the NC materials should have the different catalytic ability on the dehydration of cellulose. 相似文献
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Chlorocarbenium salts
-
of the Vilsmeier-Arnold type react with the silylated isocyanuric acid
to give 1-oxa-3-azabutatrienium salts
under mild conditions. From reactions of diarylchloromethenium salts
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with
and ketones or tertiary carboxamides high yields of 2-azaallenium salts
were obtained. A few chloro substituted 2-azaallenium salts
were prepared from
and carbonyl compounds. The mechanisms of the new reactions are discussed. 相似文献
11.
We report here, a method of accelerating the rate of aminolysis of PFP sulfonates to yield sulfonamides using tetrabutylammonium salts. We have previously explored the utility of employing PFP sulfonates in the formation of sulfonamides; however we demonstrate here the advantages of combining the existing methodology with a revised protocol which allows the diversity within both the sulfonate ester and the amine to be extended. 相似文献
12.
Fang Huang 《Tetrahedron》2007,63(32):7667-7672
A mild method for the preparation of aryl and alkenylsulfones from the cross-coupling reaction of organoboronic acids and sodium sulfinate salts is described. Optimized conditions utilize a catalytic amount of copper(II) acetate monohydrate with 1,10-phenanthroline as ligand in the presence of 4 Å molecular sieves. A co-solvent mixture of dichloromethane/DMSO was used, with reactions occurring at 40 °C under an atmosphere of oxygen. Reaction at room temperature also yields sulfone product, but in lower yields. The method tolerates a variety of substituents on the organoboronic acid, including amide, aldehyde, halide and nitro functionalities, as well as ortho-substituents. In general, the reaction is found to be less efficient using arylboronic acids bearing electron-withdrawing substituents, or using aryltrifluoroborate salts. 相似文献
13.
A pyrolysis apparatus was developed for studies over a wide temperature range. Potassium salts of xanthic acids were pyrolysed between 200 degrees and 1225 degrees . The decomposition temperatures were compared with the DTA curves of the corresponding salts. 相似文献
14.
Marimuthu Mohana Packianathan Thomas Muthiah Colin D. McMillen Ray J. Butcher 《Acta Crystallographica. Section C, Structural Chemistry》2023,79(2):61-67
The crystal structures of three compounds involving aminopyrimidine derivatives are reported, namely, 5-fluorocytosinium sulfanilate–5-fluorocytosine–4-azaniumylbenzene-1-sulfonate (1/1/1), C4H5FN3O+·C6H6NO3S−·C4H4FN3O·C6H7NO3S, I , 5-fluorocytosine–indole-3-propionic acid (1/1), C4H4FN3O·C11H11NO2, II , and 2,4,6-triaminopyrimidinium 3-nitrobenzoate, C4H8N5+·C7H4NO4−, III , which have been synthesized and characterized by single-crystal X-ray diffraction. In I , there are two 5-fluorocytosine (5FC) molecules (5FC-A and 5FC-B) in the asymmetric unit, with one of the protons disordered between them. 5FC-A and 5FC-B are linked by triple hydrogen bonds, generating two fused rings [two R22(8) ring motifs]. The 5FC-A molecules form a self-complementary base pair [R22(8) ring motif] via a pair of N—H…O hydrogen bonds and the 5FC-B molecules form a similar complementary base pair [R22(8) ring motif]. The combination of these two types of pairing generates a supramolecular ribbon. The 5FC molecules are further hydrogen bonded to the sulfanilate anions and sulfanilic acid molecules via N—H…O hydrogen bonds, generating R44(22) and R66(36) ring motifs. In cocrystal II , two types of base pairs (homosynthons) are observed via a pair of N—H…O/N—H…N hydrogen bonds, generating R22(8) ring motifs. The first type of base pair is formed by the interaction of an N—H group and the carbonyl O atom of 5FC molecules through a couple of N—H…O hydrogen bonds. Another type of base pair is formed via the amino group and a pyrimidine ring N atom of the 5FC molecules through a pair of N—H…N hydrogen bonds. The base pairs (via N—H…N hydrogen bonds) are further bridged by the carboxyl OH group of indole-3-propionic acid and the O atom of 5FC through O—H…O hydrogen bonds on either side of the R22(8) motif. This leads to a DDAA array. In salt III , one of the N atoms of the pyrimidine ring is protonated and interacts with the carboxylate group of the anion through N—H…O hydrogen bonds, leading to the primary ring motif R22(8). Furthermore, the 2,4,6-triaminopyrimidinium (TAP) cations form base pairs [R22(8) homosynthon] via N—H…N hydrogen bonds. A carboxylate O atom of the 3-nitrobenzoate anion bridges two of the amino groups on either side of the paired TAP cations to form another ring [R32(8)]. This leads to the generation of a quadruple DADA array. The crystal structures are further stabilized by π–π stacking ( I and III ), C—H…π ( I and II ), C—F…π ( I ) and C—O…π ( II ) interactions. 相似文献
15.
Yu.M. Atroshchenko I.V. Shakhkel'dyan O.V. Leonova A.N. Shumskii N.A. Troitskii I.E. Yakunina A.N. Shchukin Yu.A. Efremov 《Russian Journal of Organic Chemistry》2005,41(8):1212-1218
A series of 6,11-disubstituted 1,9-dinitro-5-oxa-11-azatricyclo[6.4.0.04,9 ]dodecan-2-ones were prepared from anionic adducts of 2,4-dinitrophenol with propanone and 2-phenylethanone carbanions by successive selective reduction with sodium borohydride and aminomethylation with formaldehyde and primary amines. By spectral methods and by quantum-chemical calculations following PM3 method the structure of the molecules synthesized was shown to contain all the three rings in a chair form with equatorial substituents in positions 6 and 11. 相似文献
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A series of 2-aryl-3-oxa-1-azaspiro[4.4]non-1-enes was prepared by cyclization of the corresponding β-acylamino alcohols (V) with thionyl chloride. Structure proofs for the β-acylamino alcohols and the spiro compounds are given. Infrared and p.m.r. data are reported. 相似文献
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Gether Irick 《Journal of heterocyclic chemistry》1970,7(1):33-37
5-Methyl-11H-isoindolo[2,1-α]benzirnidazolium halide (IV), obtained by direct quaternization of the precursor III, underwent facile condensation reactions at its 11-methylene group similar to those of 11H-isoindolo[1,2-b]benzothiazolium cation II. Although the treatment of II with alkali regenerated its precursor I, treatment of IV with alkali caused ring opening to a phthalimidine. Attempted thermal cyclization of 2-(alkylaminophenyl)phthalimidines, e.g., VII, resulted in dealkylation to produce III. 相似文献