微波促进下1-芳甲酰基-4-（2’-苯并呋喃甲酰基）氨基硫脲及其衍生物的合成

微波辐射条件下，首先由2-苯并呋喃甲酰氯在相转移条件下依次与硫氰酸铵和 芳甲酰肼反应合成了一系列1-芳甲酰基-4-（2’-苯并呋喃甲酰基）氨基硫脲，进 一步在微波辐射的条件下由这些氨基硫脲分别与碘酸钾、醋酸或醋酸汞等试剂作用 高产率地制得了1-芳甲酰基-4-（2’-苯并呋喃甲酰基）氨基脲、2-芳基-5-（2’- 苯并呋喃甲酰胺基）-1，3，4-噻二唑和2-芳基-5-（2’-苯并呋喃甲酰胺基）-1， 3，4-（口恶）二唑。     

Synthesis and spectral luminescence properties of 2-aryl-5-methyl-1,3,4-oxadiazoles and zinc(ii) 2-(2-hydroxyphenyl)-5-methyl-1,3,4-oxadiazole complex

Russian Chemical Bulletin - 2-Aryl-5-methyl-1,3,4-oxadiazoles were synthesized by reflux of equimolar amounts of acyl hydrazides with triethyl orthoacetate in o-xylene. The obtained oxadiazoles,...     

Solid‐Phase Approach for the Synthesis of 2‐Amido‐1,3,4‐oxadiazoles

A new solid‐phase approach for the synthesis of 2‐amido‐1,3,4‐oxadiazoles has been developed. In this synthesis, hydroxypentyl JandaJel polymer support was treated with excess of oxalyl chloride to give resin‐bound 2‐chloro‐2‐oxoacetate, and this intermediate was then coupled with different hydrazides to give resin‐bound 2‐(N′‐acylhydrazinyl)‐2‐oxoacetate. Intramolecular dehydrative cyclization of resulting resin‐bound linear precursor followed by direct amidation using aluminum amide reagent provided 5‐substituted 1,3,4‐oxadiazoles as 2‐carboxamides. To explore the scope of this reaction sequence, we synthesized a small set of library using a combination of hydrazides and amines, and the desired products were obtained in good to high yields.     

Synthesis and properties of azoles and their derivatives. 33. Synthesis of 1,3,4-oxadiazoles that contain an indolyl group

2,5-Disubstituted oxadiazoles with indole residues were synthesized by condensation of the hydrochlorides of the corresponding imido esters with hydrazines, as well as by cyclization of hydrazides by the action of POCl₃. 2-Substituted oxadiazoles of the same series were obtained by condensation of the corresponding hydrazides with ethyl orthoformate.See [1] for Communication 32.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 343–347, March, 1982.     

Asymmetric Synthesis and Antitumor Activity of Spiro‐Oxadiazole Derivatives from 1,4:3,6‐Dianhydro‐D‐fructose

A series of spiro‐oxadiazoles were synthesized from 1,4:3,6‐dianhydro‐D ‐fructose and hydrazides via a stereo‐ selective two‐step reaction sequence. The structures of newly synthesized compounds were established by spectral analysis. The absolute configuration of compound 2a was further confirmed by single crystal X‐ray analysis. All the synthesized compounds were screened for their in vitro antitumor activity, showing that these compounds have poor inhibitory activities against A549, MGC‐803 tumor cells.     

Synthesis of thiadiazoles,triazoles and oxadiazoles from sulfonyl acetic acids via a common route

A new class of five membered heterocycles, thiadiazoles, triazoles and oxadiazoles were prepared from sulfonyl acetic acids via acid hydrazides.     

Silica Sulfuric Acid: An Efficient and Versatile Acidic Catalyst for the Rapid and Ecofriendly Synthesis of 1,3,4‐Oxadiazoles at Ambient Temperature

A rapid and green synthesis of 2,5‐disubstituted 1,3,4‐oxadiazoles is reported. The title compounds were prepared by the reaction of different acyl hydrazides and orthoesters in the presence of silica sulfuric acid under solvent‐free conditions. In this new process, reactions were run at ambient temperature and completed in a short period of time with high yields.     

A reinvestigation of the cyclodesulfurization of thiosemicarbazides

A recent report describing the preparation of 2-(substituted-amino)-3,4-dihydro-5H-1,3,4-benzotriazepin-5-ones (3), by the cyclodesulfurization of hydrazides prepared from o-aminobenzoylhydrazine ( 1 ) and isothiocyanates, is erroneus. The products resulting from this reaction sequence are, instead, 2-(substituted-amino)-5-(o-aminophenyl)-1,3,4-oxadiazoles ( 4 ). Alternate syntheses of the oxadiazoles led to the correct structural assignments.     

A new synthetic route to 1,3,4-oxadiazoles. Pharmacological study of some new derivatives

2-Substituted 1,3,4-oxadiazoles have been examined as possible prodrugs of antidepressant hydrazides. A new method of synthesis of this heterocycle from thionoester and five new oxadiazoles substituted at the 2-position by a 4-pyridyl or 4-aminophenyl group and at the 5-position by a phenyl group are described.     

Synthesis of 2‐Amino‐1,3,4‐oxadiazoles through Elemental Sulfur Promoted Cyclization of Hydrazides with Isocyanides

A novel sulfur‐promoted cyclization of hydrazides and isonitriles to produce 1,3,4‐oxadiazole has been developed. The method is operationally simple and compatible with a wide scope of substrates and various 2‐amino‐ 1,3,4‐oxadiazoles are efficiently obtained in good yields.     

Syntheses of polyimide copolymers based on N,N′-(pyromellitoyl)diglycine

N,N′-(pyromellitoyl)diglycine ( 1 ) was synthesized by reacting pyromellitic anhydride with glycine in polar solvents such as DMAC, NMP, or DMF at 60°C and then refluxed azeotropically with toluene. Among these solvents, it is easy to form DMF-insoluble salt ( 1 ″) in DMF, but this salt can be converted to 1 by treating first with NaHCO₃ and then with HCl. Reacting monomer N,N′-(pyromellitoyl)diaminoacetyl chloride ( 2 ) can be obtained by treating with thionyl chloride, and N,N′-(pyromellitoyl)dimethyl aminoacetate ( 3 ) can be obtained by treating 2 with methanol. As 2 reacts with aromatic diamine in polar solvents, such as DMAC, DMF, or NMP, a series of copolypyromellitimide amides ( 5a–h ) can be obtained. These copolymers can be processed by using DMAC + LiCl (5%) as solvent to produce flexible film of good weather resistivity and heat resistivity. Monomer 2 can also react with aromatic dihydrazides in polar solvents to produce copolypyromellitimide hydrazides ( 6a–c ), and 6a–b can be condensated again to produce copolypyromellitimide oxadiazoles ( 7a–b ) in polyphosphoric acid (PPA). Besides, 3 reacts with aromatic tetraamine by carrying out polycondensation in PPA to produce copolypyromellitimide benzimidazole ( 8 ). Structures of copolymers mentioned above were identified by comparing IR spectra with those of model compounds. Heat resistivity was measured by the thermogravimetric method, and their solubilities in various solvents were also investigated.     

Alum (KAl(SO4)2 · 12H2O): An Efficient and Inexpensive Catalyst for the One-pot Synthesis of 1,3,4-Oxadiazoles under Solvent-Free Conditions

Summary. Alum (KAl(SO₄)₂ · 12H₂O) catalyzed the efficient synthesis of mono- and disubstituted 1,3,4-oxadiazoles by the condensation of acyl hydrazides with orthoesters under solvent-free conditions at 100°C. This methodology offers significant improvements for the synthesis of oxadiazoles with regard to the yield of products, simplicity in operation, inexpensive reagents, and green aspects by avoiding toxic catalysts and solvents.     

TiO2‐Nanoparticles Catalyzed Synthesis of New Trifluoromethyl‐4,5‐dihydro‐1,2,4‐oxadiazoles and Trifluoromethyl‐1,2,4‐oxadiazoles

Synthesis of a new series of trifluoromethyl‐4,5‐dihydro‐1,2,4‐oxadiazoles and trifluoromethyl‐1,2,4‐oxadiazoles have been described by utilizing the reactions between amidoximes and trifluoroacetimidoyl chlorides. Trifluoromethyl‐4,5‐dihydro‐1,2,4‐oxadiazoles have been synthesized under mild conditions such as Na₂CO₃, THF‐H₂O, and titanium dioxide nanoparticles as catalyst in good to excellent yields. Also, trifluoromethyl‐1,2,4‐oxadiazoles have been synthesized directly from reaction of amidoximes and trifluoroacetimidoyl chlorides in a one‐pot manner in present of NaH, THF, and titanium dioxide nanoparticle as catalyst.     

Syntheses of [1,2,3]selenadiazolo[4,5‐e]benzofuran or benzothiophene, [1,2,3]thiadiazolo[4,5‐e]benzofuran or benzothiophene,and 2‐benzofuranyl‐1,3,4‐oxodiazole derivatives

Dehydrogenation of ethyl 3‐methyl‐4‐oxo‐4,5,6,7‐tetrahydrobenzofuran‐2‐carboxylate 1 with 2,2′‐azobi‐sisobutyronitrile and N‐bromosuccinimide gave ethyl 4‐hydroxy‐3‐methylbenzofuran‐2‐carboxylate 3 . Reaction of compounds 3–4 with hydrazine hydrate afforded the corresponding hydrazides 5a‐b . The reaction of 5a‐b with aldehydes yielded substituted hydrazones 6a‐l . Compounds 7a‐d were prepared from compounds 6a‐d and bromine in acetic acid. Lead tetraacetate oxidation of compounds 6e‐l afforded substituted oxadiazoles 8e‐l . Selenium dioxide oxidation of 4‐oxo‐4,5,6,7‐tetrahydrobenzofuran semicarbazones 9, 14a and 4‐oxo‐4,5,6,7‐tetrahydrobenzothiophene 14b gave the tricyclic 1,2,3‐selenadiazoles 10, 15a and 15b respectively. Reaction of semicarbazones 9, 14a and 14b with thionyl chloride afforded the corresponding 1,2,3‐thiadiazoles 12, 16a and 16b respectively.     

Synthesis of 2‐Coumarinyl and Spiroindolyl‐5‐Phenyl‐1,3,4‐Oxadiazoles

The 2H‐1‐benzo/naphthopyran‐2‐one‐4‐yl (un)substituted phenyl‐1,3,4‐oxadiazoles has been synthesized by the oxidative cyclization of benzoic acid hydrazides formed in situ by the condensation of the respective 2H‐1‐benzo/naphthopyran‐2‐one‐4‐carboxaldehyde and (un)substituted monobenzoyl hydrazide in moderate yields. Also, spiro[indoline‐thiozolidine]‐2,4′‐diones has been syhthesized in a similar way from 3‐phenyl‐spiro[3H‐indoline‐3,2′‐thiozolidine]‐2,4′‐(1 H)dione monohydrazide and (un)substituted benzaldehydes.     

One-pot Synthesis of 1- Aryloxyacety l - 4- (4′-nitrophenyloxyacetyl) - thiosemicarbazides under Phase Transfer Catalysis and Microwave Irradiation

The 1-aryloxyacetyl-4-(4′-nitrophenyloxyacetyl)-thiosemicarbazides (3a-h) are synthe- sized via reaction of 4-nitrophenyloxyacetyl chloride with ammonium thiocyanate and aryloxyacetic hydrazides (2a-h) under phase transfer catalysis and microwave irradiation in excellent yield.     

Pyrrolo[1,2-d]triazines-1,2,4. I. Dérivés pyrroliques

Pyrrole hydrazides and hydrazones were synthesized from pyrrole-2-carboxylic acid and pyrrole-2-carboxaldehyde, The 2-pyrrolyloxadiazoles and thiadiazoles were obtained by cyclising the pyrrole hydrazides with phosphorus oxychloride and tetraphosphorus decasulphide. These derivatives have been used for the synthesis of pyrrolo[1,2-d]-1,2,4-triazines by cyclisation or rearrangement.     

One-pot Synthesis of 1-Aryloxyacety l-4-(4''''-nitrophenyloxyacetyl)-thiosemicarbazides under Phase Transfer Catalysis and Microwave Irradiation

1,4-Disubstituted thiosemicarbazides have attracted much attention in recent years because of their fungicidal1-2, bactericidal3-4 and tuberculostatic5-6 activities. Meanwhile, aryloxy acetic acid derivatives have also been used as herbicides and plant-growth regulators7-10. These applications prompt us to develop a simple and rapid synthetic method to prepare a series of new compounds bearing both thiosemicarbazide and aryloxyacetyl moieties, with the object of obtaining new biologically ac…     

Synthesis of Derivatives of 1-(9-Alkyl-9H-carbazol-3-yl)-4-carboxy-2-pyrrolidinones

Derivatives of 1-(9-alkyl-9H-carbazol-3-yl)-4-carboxy-2-pyrrolidinones (methyl esters, hydrazides) were synthesized. The condensation of the synthesized hydrazides with aromatic aldehydes, acetylacetone, and acetoacetic ester was studied. Structure of the obtained compounds was confirmed by IR and NMR spectroscopy. The specific characteristics of the substituents are discussed.     

One‐pot Synthesis of 2,5‐Disubstituted‐1,3,4‐oxadiazoles Based on the Reaction of N,N‐Dimethyl Amides with Acid Hydrazides

Convenient and efficient one pot method for the synthesis of 2,5‐disubstituted‐1,3,4‐oxadiazoles based on the reaction of N,N‐dimethyl amides with acid hydrazides has been developed. The methodology is applied to a wide range of difference aryl hydrazide and difference N,N‐dimethyl amides to 2,5‐disubstituted‐1,3,4‐oxadiazoles yield the in good to excellent yields. It will be possible wide useful application in synthesis.