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1.
Zelong Wang Silin Chen Prof. Dr. Chao Chen Dr. Yunhui Yang Prof. Dr. Congyang Wang 《Angewandte Chemie (International ed. in English)》2023,62(6):e202215963
Earth-abundant transition metal catalysis has emerged as an important alternative to noble transition metal catalysis in hydrogenation reactions. However, there has been no Earth-abundant transition metal catalyzed hydrogenation of thioamides reported so far, presumably due to the poisoning of catalysts by sulfur-containing molecules. Herein, we described the first manganese-catalyzed hydrogenative desulfurization of thioamides to amines or imines. The key to success is the use of MnBr(CO)5 instead of commonly-employed pincer-manganese catalysts, together with simple NEt3 and CuBr. This protocol features excellent selectivity on sole cleavage of the C=S bond of thioamides, in contrast to the only known Ru-catalyzed hydrogenation of thioamides, and unprecedented chemo-selectivity tolerating vulnerable functional groups such as nitrile, ketone, aldehyde, ester, sulfone, nitro, olefin, alkyne and heterocycle, which are usually susceptible to common hydride-type reductive protocols. 相似文献
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3.
Interesting skeletal rearrangements, resulting in the formation of unexpected fragments, have been noticed in the mass spectra of aromatic thioamides of cyclic amines such as piperidine, morpholine and pyrrolidine. Suitable mechanisms, based on mass analysed ion kinetic energy spectra, high voltage scan spectra and high resolution data, have been proposed for the formation of [M? SH]+ ions and the fragment at m/z (103+R) in the mass spectra of these compounds. The mass spectra of the thioamides of non-cyclic amines and the thioamides of aliphatic acids contain peaks corresponding to a four-centred skeletal rearrangement followed by the elimination of either the thioalkoxy or the thiophenoxy radical from the molecular ions. 相似文献
4.
The synthesis of the new 2H‐azirin‐3‐amines (‘3‐amino‐2H‐azirines') 11, 20, 28 , and 33 as dipeptide synthons is described. The reactions of the starting amides with Lawesson reagent gave the corresponding thioamides, and consecutive treatment with COCl2, 1,4‐diazabicyclo[2.2.2]octane (DABCO), and NaN3 led to the desired products. It is shown that these 2H‐azirin‐3‐amines can conveniently be used as building blocks of the dipeptides Aib‐(Me)Axx (Axx=alanine, valine), Aib‐Homoproline, and Iva‐Pro in the synthesis of several model peptides. However, some limitations apply for the synthesis of such 2H‐azirin‐3‐amines. The starting material for the azirine synthesis, the corresponding thioamides, cannot generally be synthesized, and the 2H‐azirin‐3‐amines could not be obtained in all cases from the thioamides prepared. 相似文献
5.
L. Kramberger P. Loren
ak S. Polanc B. Ver
ek B. Stanovnik M. Tiler F. Povaanec 《Journal of heterocyclic chemistry》1975,12(2):337-342
The formation of heterocyclic thioamides from alkylpyridines, heteroaromatic amines and sulfur was investigated. Oxidative cyclization of these thioamides afforded the corresponding thiazoloazines. Attempted thiation of some hydrazones gave triazolopyridines and some examples of direct thiation of heterocycles are given. 相似文献
6.
An efficient and selective multicomponent oxidative coupling of two different aliphatic primary amines into thioamides by elemental sulfur under solvent-free conditions has been developed. 相似文献
7.
A variety of amides have been selectively reduced to the corresponding amines via conversion to their thioamides and treatment with triethyloxonium tetrafluoroborate followed by sodium borohydride. This procedure is compatible with isolated and conjugated double bonds, esters, intro groups, and sulfonamides. 相似文献
8.
New heterocyclic scaffolds can be easily prepared by the coupling of heteroaromatic phenols (pyridines, pyrimidines) with carbonyl compounds, amines, and isocyanides. This transformation related to the Ugi reaction probably involves a Smiles rearrangement. The scope of this methodology is further extended by the successful use of heterocyclic thiols to form highly functionalized thioamides. 相似文献
9.
Iodine-mediated, oxidative desulfurization promoted cyclization of N-2-pyridylmethyl thioamides serves as an efficient and versatile method for the preparation of 2-azaindolizines (imidazo[1,5-a]pyridines) and rare 2-azaindolizine sulfur-bridged dimers. The 2-azaindolizines prepared in this manner are readily converted to a variety of fluorescent compounds by using transition-metal-catalyzed cross-coupling reactions. [reaction: see text]. 相似文献
10.
A systematic exploration of thiophilic ability of o-iodoxybenzoic acid (IBX) for oxidative desulfurization to trigger domino reactions leading to new methodologies for synthesis of different azoles is described. A variety of highly substituted oxadiazoles, thiadiazoles, triazoles, and tetrazoles have been successfully synthesized in good to excellent yields, starting from readily accessible thiosemicarbazides, bis-diarylthiourea, 1,3-disubtituted thiourea, and thioamides. 相似文献
11.
Methods developed with N-(benzoyloxy)amines and hydroxamic acids were used in the synthesis of N-(hydroxy)amide-containing pseudopeptides. Acylation of N-(benzoyloxy)phenethylamine with the acid chloride of N(alpha)-Fmoc-L-leucine provided a N(alpha)-Fmoc-N-(benzoyloxy)-L-leucinamide in 90% yield. Deprotection of the benzoyl group (using 10 vol % NH(4)OH/MeOH) provided the N(alpha)-Fmoc-N-(hydroxy)-L-leucinamide in 87% yield. In general, the appended Fmoc group allowed for further elaboration of the N-hydroxy-N-(alkyl)amides using classic peptide-coupling methods. A practical synthetic strategy was developed, and racemization issues were addressed using diastereomeric Val-Leu derivatives. In addition, N-(hydroxy)thioamides were generated from the corresponding N-(benzoyloxy)thioamides. N-(Benzoyloxy)thioamides were obtained in moderate yields (53-76%) from the reaction of the corresponding N-(benzoyloxy)amides with Lawesson's reagent (i.e., 2, 4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disu lfide). In summary, this new technology allows for the introduction of either N-hydroxyamide or N-(hydroxy)thioamide linkages into pseudopeptide chains without racemization. 相似文献
12.
Substituted thiapyrrolizidinones and fused pyridones, and quinolizinones were reported efficaciously from suitable thioamides in yields ranging from 30% to 65%. The reaction proceeded in a one-pot procedure as cascade process by the intramolecular 1,3-dipolar cycloaddition of thioisomünchnones followed by desulfurization of the adducts. During these investigations, the mechanistic aspects of the process were also discussed. 相似文献
13.
I. S. Fedorovich N. I. Ganushchak V. V. Karpyak N. D. Obushchak A. I. Lesyuk 《Russian Journal of Organic Chemistry》2007,43(8):1190-1195
Interaction of 5-arylfurfurals or arylaldehydes with secondary amines (monosubstituted piperazines, morpholine, piperidine) and sulfur under conditions of Wilgerodt-Kindler reaction provided N-substituted thioamides of 5-arylfuran-2-carboxylic and benzoic acids. 相似文献
14.
The novel reactivity of O-silylthionoesters with amine nucleophiles to generate oxoamides (rather than thioamides) is described. A straightforward first-generation trimethylsilylation protocol using bistrimethylsilylacetamide (BSA) combined with the unique reactivity of the O-silylthionoesters toward 1° and 2° amines to generate oxoamides provides the simplest means of activating a thiol acid for peptide bond formation at neutral pH. Excellent stereoretention is observed. 相似文献
15.
I. Jabre M. Saquet A. Thuillier 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):283-285
Abstract Convenient syntheses of S-aryldithioesters and thioamides are described: thus, thiols and amines are readily thioacylated with the S-borondithioester formed in situ, by the mild reaction of a dithioacid with 9-BBN. 相似文献
16.
[reaction: see text] Reaction of N-(2-phthalimidoethyl)-N-alkylisopropylamines and S(2)Cl(2) gave atropisomeric (by dynamic NMR) 4-N-(2-phthalimidoethyl)-N-alkylamino-5-chloro-1,2-dithiole-3-thiones that quantitatively cycloadded to dimethyl or diethyl acetylenedicarboxylate to give a novel class of stable thioacid chlorides, which in turn reacted with 1 or 2 equiv of secondary amines to give thioamides. 相似文献
17.
Androsov DA 《The Journal of organic chemistry》2008,73(21):8612-8614
4-(2-Chloro-5-nitrophenyl)-1,2,3-thiadiazole undergoes ring-opening to produce a thioketene intermediate that reacts with secondary amines forming 2-(2-chloro-5-nitrophenyl)-N,N-dialkylthioacetamides. Intramolecular cyclization of these thioamides via nucleophilic substitution of the halogen on the aromatic ring affords nonaromatic 1,1-dialkylindolium-2-thiolates instead of the expected aromatic N,N-dialkylaminobenzo[b]thiophenes. 相似文献
18.
Kai F. G. Averesch Henner Pesch Dr. Christopher Golz Prof. Dr. Manuel Alcarazo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(44):10472-10477
A synthetic method has been developed for the preparation of dihalo(pyridinium)sulfuranes and their transformation into alkynylthiopyridinium salts, starting from inexpensive thiopyridones. The reactivity of these salts towards different nucleophiles is evaluated. Most thiols and amines are converted into dithioesters and thioamides, respectively; whereas sterically demanding thiols delivered alkynylthioethers. These results, together with preliminary mechanistic studies reveal that alkynylthiopyridinium salts can be considered synthetic equivalents of unstable thioketenes. 相似文献
19.
Adnan H. M. Al-Shaar David W. Gilmour David J. Lythgoe Ian Mcclenaghan Christopher A. Ramsden 《Journal of heterocyclic chemistry》1989,26(6):1819-1825
Reactions of various five-and six-membered C-methylheterocycles with hot thionyl chloride gave chlorothio intermediates which were not characterized but which gave 1,2,4-thiadiazole derivatives when reacted with amidines and gave thioamides when reacted with amines. When 2,3-dimethyl-6-ethoxycarbonylimidazo-[4,5-b]pyridine ( 26 ) was treated with thionyl chloride a trisulphane 27 was isolated. 相似文献
20.
Ya. L. Gol'dfarb É. A. Krasnyanskaya B. P. Fabrichnyi 《Russian Chemical Bulletin》1962,11(10):1731-1740
Summary A new method was developed for the preparation of primary aliphatic and alicyclic amines by the reductive desulfurization of oximes and amines containing a thiophene nucleus with the aid of Raney nickel. 相似文献