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1.
When 2,5-dihydroxy-3,4,6,7-tetrachloro-2,3-dihydrobenzo[b]furan interacts in acetone with thiosemicarbazide or its 4-methyl or 4-phenyl derivative, the respective products are 5-(2,5-dihydroxy-3,4,6-trichlorophenyl)-2-(isopropylidenehydrazino)thiazole and -3-R-2-(isopropylidenazino)thiazolines, respectively. It has been shown that hydrolysis of these compounds forms 3-amino-5-(2,5-dihydroxy-3,4,6-trichlorophenyl)-2-imino(or 2-R-imino)thiazolines. These products of hydrolysis and their predecessors are oxidized to the corresponding 2-hetaryl-substituted 3,5,6-trichloro-1,4-benzoquinones.Riga Technical University, Riga, LV-1048. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1424–1431, October, 1996. Original article submitted July 1, 1996.  相似文献   

2.
《中国化学会会志》2018,65(2):189-204
The review summarizes the synthesis of different thiophene, pyrazole, and thiazole derivatives by refluxing 9a in ethanol with a catalytic amount of TEA or leaving it in DMF containing potassium carbonate at room temperature overnight to afford the corresponding thiophene derivative 10a . In addition, cyclization of Schiff bases with thioglycollic acid in the presence of a catalytic amount of ZnCl2 yielded novel thiophene derivatives. Condensation of 2‐substituted‐4‐methylythio semi‐carbazides 92 with carbonyl compounds under strong acidic conditions afforded 2‐thiazolines. Also, carboxylic acid reacted with 2‐thioethylamine in the presence of triphenylphosphine and triethylamine to afford 2‐thiazolines 98 .  相似文献   

3.
The total synthesis of dendroamide A (1), a multidrug-resistance reversing bistratamide-type peptide-derived macrocycle, has been accomplished in 19% yield. Fmoc-protected amino acids were condensed into appropriately protected dipeptides which were treated with bis(triphenyl)oxodiphosphonium trifluoromethanesulfonate to afford oxazoles and thiazolines (oxidized to thiazoles) with high chemo- and stereoselectivity. The convergent condensation of three heterocyclic amino acids followed by macrocyclization afforded the natural product.  相似文献   

4.
New 1-cycloalkenyl-1-diazenes have been obtained in good yields from cyclic β-ketoesters and hydrazine derivatives. They furnished new cycloalkyl[d][1,3]thiazolines with thioamides or new spirocycloalkyl-thiazolinones with thioureas. Moreover they gave, with imidazolidine-2-thione and tetrahydropyrimidine-2-thione, new and interesting spiro[cycloalkyl-1,2′-imidazo[2,1-b][1,3]thiazole] or spiro[cycloalkyl-1,2′-[1,3]thiazolo[3,2-a]pyrimidine] derivatives, respectively. Cycloalkyl[d][1,3]thiazolines were useful for the further preparation of unknown thia-triaza-tricyclo derivatives. Novel hexahydro-1,3-benzothiazoles have been achieved by reaction of N,N′-dialkylthioureas on N-1-phenyl-2-(1-cyclohexenyl)-1-diazene-1-carboxyamide. The acidic hydrolysis of spirocycloalkyl-thiazolinones produced 2-imino-5-(ω-carboxyalkyl)-4-thiazolidinones.  相似文献   

5.
Δ2‐Thiazolines are interesting heterocycles that display a wide variety of biological characteristics. They are also common in chiral ligands used for asymmetric syntheses and as synthetic intermediates. Herein, we present asymmetric routes to 2,4,5‐trisubstituted Δ2‐thiazolines. These Δ2‐thiazolines were synthesized from readily accessible/commercially available α,β‐unsaturated methyl esters through a Sharpless asymmetric dihydroxylation and an O→N acyl migration reaction as key steps. The final products were obtained in good yields with up to 97 % enantiomeric excess.  相似文献   

6.
A new approach to the synthesis of 2‐R‐5‐benzyl‐2‐thiazolines with the use of chloro‐ and bromoarylation products of allyl isothiocyanate with arenediazonium halides was elaborated. The isothiocyanates obtained were reacted with ammonia, aliphatic or aromatic amines, and sodium methoxide. The use of ammonia or weakly basic amines in this reaction allowed. Intermediate thioureas to be isolated. On the basis of 1H NMR spectra, amino–imino tautomerism of the synthesized 2,5‐disubstituted 2‐thiazolines were analyzed. 2‐Arylamino‐5‐benzyl‐2‐thiazolines exist mainly in the Z‐configuration of the imino form. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 517–525, 1999  相似文献   

7.
Ortho‐, meta‐, or para‐nitro benzoic acid were refluxed with excess SOCl2 to give acyl chloride, which condensed with β‐amino alcohol in the presence of Et3N in dichloromethane to afford β‐hydroxyamide; finally, sulphonation and cyclization were simultaneously conducted to afford 1,3‐thiazoline derivatives. Fungicidal activity of these new thiazolines against eight agrocultural fungi were evaluated, and two of this type of compounds displayed good fungicidal activity comparable or superior to commercial fungicide chlorothalonil against two fungi at a concentration of 50 mg/L. J. Heterocyclic Chem., (2011).  相似文献   

8.
Pentacarbonyl[(cyclopropyl)methoxymethylene]molybdenum complex reacts with ferrocenyl alkynes to afford ferrocenyl-substituted 2,4-cycloheptadienones as major products, accompanied by varying amounts of 2-cycloheptene-1,4-diones and/or 2-cyclobutenones. 2-Cycloheptene-1,4-diones are secondary reaction products and result from initially formed 2,4-cycloheptadienones via hydrolysis. In one reaction, a hydroxy-substituted 2,4-cycloheptadienone derivative was isolated, which was not observed previously from similar reactions.  相似文献   

9.
New 1,5-dimethyl-4-phenylimidazolidin-2-one-derived acyclic chiral iminic glycine reagents have been prepared and diastereoselectively alkylated with activated alkyl halides and electrophilic olefins in the presence of lithium chloride under (a) strong bases (LHMDS, KOBu(t)) and low temperature (-78 degrees C) conditions, (b) solid-liquid phase-transfer catalysis reaction (LiOH, TBAB, -20 degrees C) conditions, and (c) in the presence of organic bases (DBU, BEMP, TMG, -20 degrees C). In the case of dielectrophiles C- and N-alkylation takes place to afford heterocyclic derivatives. Hydrolysis of alkylated products has been carried out (a) in two-step procedures with LiOOH or LiOH followed by acidic hydrolysis or Dowex purification, (b) in one single-step under refluxing water to give the corresponding alpha-amino acid, (c) in the presence of DBU in methanol to provide N-protected alpha-amino acids methyl esters, or (d) by a protection-hydrolysis procedure to afford N-Boc-protected alpha-amino acids. The chiral imidazolidinone has generally been recovered in good yield. This methodology has been shown to be useful for the synthesis of acyclic and heterocyclic (S)- and (R)-alpha-amino acids.  相似文献   

10.
An efficient synthetic route to construct disubstituted benzodifurans from dihydroxy- or diacetoxy-dialkynylbenzenes utilizing Cs2CO3 or Pd(OAc)2/Cs2CO3 promoted double annulations is described. The scope for the reaction in the presence of a catalytic amount of Pd(OAc)2 is more general. In addition, it was observed that NaOH-promoted reaction of diacetoxy-dialkynylbenzenes may directly afford in THF/MeOH/H2O at 80 °C benzodifurans through hydrolysis and double cyclization in a one-pot manner. However, in most cases, the reaction is less selective affording a mixture of the double cyclization products and monocyclization–hydrolysis products.  相似文献   

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