- Triethanolamine as an inexpensive and efficient catalyst for the green synthesis of novel 1H-pyrazolo[1,2-a]pyridazine-5,8-diones under ultrasound irradiation in water and their antibacterial activity
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Triethanolamine was found to be an efficient catalyst for the synthesis of new 1H-pyrazolo[1,2-a]pyridazine-5,8-diones by a one-pot reaction of maleic hydrazide, with aromatic aldehydes and malononitrile in H2O under ultrasonic irradiation. The advantages of this method are the use of an inexpensive and readily available catalyst, easy workup, improved yields, and the use of H2O as a green solvent. To assess their antibacterial activity, all the synthesized compounds were dissolved in DMSO and subjected to biological evaluation using the disc diffusion method against 3 Gram positive and 3 Gram negative bacteria. This journal is
- Khoraamabadi-Zad, Ahmad,Azadmanesh, Mohammad,Karamian, Roya,Asadbegy, Mostafa,Akbari, Maryam
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- UV-induced photoisomerization of maleic hydrazide
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Monomers of maleic hydrazide (3-hydroxypyridazin-6-one) were studied using the experimental matrix-isolation technique as well as DFT and QCISD methods of quantum chemistry. The oxo-hydroxy tautomer was theoretically predicted to be the most stable form o
- Reva, Igor,Almeida, Bruno J. A. N.,Fausto, Rui,Lapinski, Leszek
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- Synthesis of new derivatives of pyridazino[6,1-c]pyrimido[5,4-e][1,2,4]triazine; a novel heterocyclic system
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Several derivatives of the novel pyridazino[6,1-c]pyrimido[5,4-e][1,2,4]triazine ring system have been synthesised through heterocyclisation of 5-bromo-2,4-dichloro-6-methylpyrimidine with 3-chloro-6-hydrazinylpyridazine followed by treatment with secondary amines in boiling ethanol.
- Akaberi, Toktam,Shiri, Ali,Sheikhi-Mohammareh, Seddigheh
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- Highly Chemoselective Synthesis of Novel 6- O -phosphorylated 6-Hydroxypyridazine-3(2H)-one
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6-O-Phosphorylated pyridazine-3(2H)-one derivatives were conveniently prepared by a facile method. Maleic hydrazide was prepared by the condensation of maleic anhydride with 85% hydrazine hydrate. It was then chemoselectively phosphorylated at the 6-O position using the Atherton-Todd reaction. An efficient, highly chemoselective method to synthesize 6-O-phosphorylated pyridazin-3(2H)-one derivatives is provided, and the approach has the merits of mild reaction conditions. GRAPHICAL ABSTRACT.
- Ju, Zhiyu,Li, Gongchun,Wang, Mei,Yang, Fengling,Ye, Yong,Zhao, Yufen
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- Dramatically enhanced fluorescence of heteroaromatic chromophores upon insertion as spacers into oligo(triacetylene)s
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In continuation of a previous study on the modulation of π-electron conjugation of oligo(triacetylene)s by insertion of central hetero-spacer fragments between two (E)-hex-3-ene-1,5-diyne ((E)-1,2-diethynylethene, DEE) moieties (Fig. 1), a new series of trimeric hybrid oligomers (14-18 and 22-24, Fig. 2) were prepared (Schemes 1-3). Spacers used were both electron-deficient (quinoxaline-based heterocycles, pyridazine) and electron-rich (2,2′-bithiophene, 9,9-dioctyl-9H-fluorene) chromophores. With 19-21 (Scheme 4), a series of transition metal complexes was synthesized as potential precursors for nanoscale scaffolding based on both covalent acetylenic coupling and supramolecular assembly. The UV/VIS spectra (Fig. 3) revealed that the majority of spacers provided heterotrimers featuring extended π-electron delocalization. The new hybrid chromophores show a dramatically enhanced fluorescence compared with the DEE dimer 13 and homo-trimer 12 (Fig. 5). This increase in emission intensity appears as a general feature of these systems: even if the spacer molecule is non-fluorescent, the corresponding hetero-trimer may show a strong emission (Table 2). The redox properties of the new hybrid chromophores were determined by cyclic voltammetry (CV) and rotating-disk voltammetry (RDV) (Table 3 and Fig. 5). In each case, the first one-electron reduction step in the hetero-trimers appeared anodically shifted compared with DEE dimer 13 and homo-trimer 12. With larger spacer chromophore extending into two dimensions (as in 14-18, Fig. 2), the anodic shift (by 240-490 mV, Table 3) seems to originate from inductive effects of the two strongly electron-accepting DEE substituents rather than from extended π-electron conjugation along the oligomeric backbone, as had previously been observed for DEE-substituted porphyrins.
- Edelmann, Michael J.,Raimundo, Jean-Manuel,Utesch, Nils F.,Diederich, Francois,Boudon, Corinne,Gisselbrecht, Jean-Paul,Gross, Maurice
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- Synthesis and anticonvulsant activity of novel 1-substituted-1,2-dihydro-pyridazine-3,6-diones.
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The synthesis and pharmacological evaluation of novel 1-substituted-1,2-dihydro-pyridazine-3,6-diones (4a--l, 5a--j) as potential anticonvulsant agents are described. The compounds were tested in vivo for the anticonvulsant activity. The compound which have maximum protection against MES induced seizures is 1-[3-(2-aminophenylamino)-2-hydroxypropyl)-1,2-dihydro-pyridazine-3,6-dione 4h (ED(50)=44.7 mg x kg(-1) i.p.) 1-[2-hydroxy-3-piperazin1-yl-propyl)-1,2-dihydro-pyridazine-3,6-dione 4c (ED(50)=72 mg x kg(-1) i.p.) and 1-[2-hydroxy-3-imidazol-1-yl-propyl)-1,2-dihydro-pyridazine-3,6-dione 4d (ED(50)=79 mg x kg(-1) i.p.) were also found to have maximum protection against MES induced seizures. Whereas all these compounds failed to protect the animals from subcutaneous pentylenetetrazole (Metrozol) seizure threshold test (sc-Met).
- Sivakumar, Ramaiah,Anbalagan, Navaneetharaman,Gunasekaran, Vedachalam,Leonard, Joseph Thomas
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- The Mechanism of Thermal Eliminations. Part 18. Relative Rates of Pyrolysis of 2-Ethoxypyrazine, 3-Ethoxypyridazine, 2-and 4-Ethoxypyrimidine, 3-Chloro-6-ethoxypyridazine, and 2-Chloro-4-ethoxypyrimidine : the Effect of the Aza 'Substituent' and ?-Bond Order on the Elimination Rate
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A kinetic study has been made of the first-order thermal decomposition of the title compounds into ethylene and the corresponding aza-substituted pyridines, between 650 and 713 K.The relative elimination rates at 650 K are (2-ethoxypyridine = 1): 0.545, 10.0, 1.03, 1.12, 9.68, and 3.28, respectively.The electronic effects of the aza 'substituent' are small, and a more important factor appears to be the C-N ?-bond order; this latter accounts for the high reactivity of the pyridazines.The effects of the chloro substituent and of the aza 'substituent' are explicable in terms of a balance between electron withdrawal from the C-O bond (producing deactivation) and from the nitrogen involved in the cyclic transition state (producing deactivation).The effects of the chloro substituents confirm that the most important step of the reaction is breaking of the C-O bond.The statistically corrected rate (per ring nitrogen) of 2-ethoxypyrimidine is unexpectedly low.This may reflect difficulty in achieving the coplanar transition state in which the lone pairs in the s-orbitals of oxygen and the nitrogen not involved in the elimination are brought into close proximity.
- Al-Awadi, Nouria,Taylor, Roger
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- Liquid Phase Synthesis of 1,2-Dihydropyridazine-3,6-dione in the Presence of Ionite Catalysts
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Abstract: The catalytic activity of synthetic ion-exchange resins was studied in the reaction between cis-butenedioic acid and hydrazine (aqueous medium; temperature, 95°C; 2–4 h) with the formation of heterocyclic hydrazide–1,2-dihydropyridazine-3,6-dione. It is established that the most effective catalysts are KU?2-8 and KRF-10P cation exchangers. A probable mechanism of the process with the formation of adsorption complexes and the participation of fixed polymer-bound sulfonate ions and counterions of the cation exchanger is proposed on the basis of IR spectroscopic studies.
- Baeshov, A. B.,Dzhumadullaeva, S. A.
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p. 954 - 957
(2021/06/07)
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- COMPOSITIONS OF DICARBOXYLIC ACID DERIVATIVES
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The present invention relates to agricultural compositions containing dicarboxylic acid hydrazides and transition metal ions, and the preparation thereof. The compositions are useful in the treatments of plants or seeds as an anti-sprout agent, growth regulator and/or pest control agent. In particular, it relates to maleic hydrazide combined with copper, nickel, manganese, iron or zinc. The transition metal ions improve the storage stability of the dicarboxylic acid hydrazide and prevent generation of free hydrazine.
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Page/Page column 12; 13
(2021/01/22)
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- Preparation method of 3, 6-dihydroxypyridazine
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The invention provides a preparation method of 3, 6-dihydroxypyridazine, which comprises the following step: by using maleic anhydride and hydrazine hydrate as raw materials and 1, 3-diene substance as a catalyst, performing reaction to obtain the product 3, 6-dihydroxypyridazine. Finally, the reaction can be carried out for a short time at a relatively low temperature, so that the product 3, 6-dihydroxypyridazine can be obtained with high yield and high purity. In the later period of reaction, a certain amount of organic matter containing two or more hydrophilic groups is added into the system, reaction is conducted for a period of time at high temperature, the content of harmful impurity amine substances in the product can be remarkably reduced, the product quality is remarkably improved, the requirements of high-end markets such as European and American markets are met, and adverse effects on the yield of the product at high temperature are avoided. The 1, 3-diene substance catalystused in the method is recovered in the heating stage and is recycled, the environmental protection requirement is met, the cost is reduced, and energy conservation and emission reduction are achieved.
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Paragraph 0023-0028; 0036-0063
(2020/07/08)
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- AMINOIMIDAZOPYRIDINES AS KINASE INHIBITORS
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Compounds having formula (I), and enantiomers, and diastereomers, stereoisomers, pharmaceutically-acceptable salts thereof, (I) are useful as kinase modulators, including RIPK1 modulation. All the variables are as defined herein.
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Page/Page column 90
(2019/05/22)
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- Natural product-based pesticide discovery: Design, synthesis and bioactivity studies of N-amino-maleimide derivatives
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Natural products are an important source of pesticide discovery. A series of N-amino-maleimide derivatives containing hydrazone group were designed and synthesized based on the structure of linderone and methyllinderone which were isolated from Lindera erythrocarpa Makino. According to the bioassay results, compounds 2 and 3 showed 60% inhibition against mosquito (Culex pipiens pallens) at 0.25 μg·mL?1. Furthermore, the results of antifungal tests indicated that most compounds exhibited much better antifungal activities against fourteen phytopathogenic fungi than linderone and methyllinderone and some compounds exhibited better antifungal activities than commercial fungicides (carbendazim and chlorothalonil) at 50 μg·mL?1. In particular, compound 12 exhibited broad-spectrum fungicidal activity (>50% inhibitory activities against 11 phytopathogenic fungi) and compounds 12 and 14 displayed 60.6% and 47.9% inhibitory activity against Rhizoctonia cerealis at 12.5 μg·mL?1 respectively. Furthermore, compound 17 was synthesized, which lacks N-substituent at maleimide and its poor antifungal activity against Sclerotinia sclerotiorum and Rhizoctonia cerealis at 50 μg·mL?1 showed that the backbone structure of N-amino-maleimide derivatives containing hydrazone group was important to the antifungal activity.
- Song, Xiangmin,Liu, Chunjuan,Chen, Peiqi,Zhang, Hao,Sun, Ranfeng
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- Preparation method of 3,6-dihydroxypyridazine
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The invention relates to a preparation method of 3,6-dihydroxypyridazine, which includes the following steps: 1) preparing raw materials, comprising maleic anhydride, hydrazine hydrate and a polybasic carboxylic acid, according to the molar ratio of 1:1:1, adding a low-boiling-point solvent to the raw materials, and performing a reaction at 0-90 DEG C for 0.5-3 h; 2) increasing temperature, and evaporating out the low-boiling-point solvent and condensing the solvent for the reaction in next batch; 3) increasing temperature to higher than 105 DEG C, performing a reaction for 0.5-5 h, and cooling, separating and purifying a product to obtain a pure 3,6-dihydroxypyridazine product, wherein a mother liquid, after the product is separated, is used as a solvent in the reaction in next batch and is used repeatedly. During backflow, water generated in the reaction can be removed. The method basically not changes processes and equipment in conventional methods, can achieve ultra-low emission, and can satisfy environment-protective demands.
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Paragraph 0011-0015
(2017/12/29)
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- Maleic hydrazide synthetic process
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A maleic hydrazide synthetic process comprises the steps of 1, adding maleic anhydride and an organic solvent into a reaction still, and conducting stirring to enable maleic anhydride and the organic solvent to be fully dissolved; 2, adding acid, water and hydrazine hydrate for temperate-controlled reaction; 3, steaming out the organic solvent through heating reflux, and recovering the organic solvent at the same time; 4, conducting heating reflux reaction again; 5, conducting cooling filtration, and recycling filtrate as water phase; 6, conducting recrystallization on filter cakes with the recovered organic solvent, obtaining maleic hydrazide through filtration, and recyling mother liquor, namely the organic solvent; 7, drying and packing maleic hydrazide. Compared with the prior art, the process has the advantages that the consumption of hydrazine hydrate is low (below 20%), production cost is low, and the residual amount of highly toxic hydrazine hydrate is small (smaller than 1 PPm).
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Paragraph 0010
(2017/07/21)
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- Maleic hydrazide preparation method
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The invention discloses a maleic hydrazide preparation method. The method comprises the following steps: heating and reacting hydrazine hydrate and diluted sulfuric acid under the action of a rare earth compound catalyst, adding maleic anhydride, carrying out a ring closure reaction, and adding an inorganic alkali to neutralize the obtained product in order to obtain maleic hydrazide. The rare earth trifluoromethanesulfonate catalyst is added in the reaction, and the inorganic alkali is used to carry out neutralization treatment after the reaction in order to realize the completeness of the reaction of the raw materials hydrazine hydrate and diluted sulfuric acid, so the maleic hydrazide yield is improved by 10% or above, and the content of residual hydrazine in the maleic hydrazide is controlled to be 2ppm or below and reaches international standards. The method has the advantages of reasonable synthesis technology, low cost, high quality, and suitableness for industrial production.
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Paragraph 0023
(2016/12/01)
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- Green and efficient synthesis of 2-(4-oxo-3,4-dihydroquinazolin-2-yl)-2,3-dihydropthalazine-1,4-dione
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2-Hydrazinoquinazolin-3H-4-ones 1a,b were reacts with each of the anhydrides, phthalic anhydride 2a, succinic anhydride 2b and maleic anhydride 2c independently in PEG-600 at RT to yield 2-(2-(4-oxo-3,4-dihydroquinazolin-2-yl)hydrazineecarbonyl) benzoic acid 3a,b, 4-oxo-4-(2-(4-oxo-3,4-dihydroquinazolin-2-yl)hydrazinyl)butanoic acid 3c,d and 4-oxo-4-(2-(4-oxo-3,4-dihydroquinazolin-2-yl)hydrazinyl)but-2-enoic acid 3e,f, respectively. 3a, b, 3c,d, 3e,f have been transformed into 2-(4-oxo-3,4-dihydroquinazolin-2-yl)-2,3-dihydrophthalazine-1,4-dione 4a,b, 1-(4-oxo-3,4-dihydroquinazolin-2-yl)piperazine-3,6-dione 4c,d and 1-(4-oxo-3,4-dihydroquinazolin-2-yl)-1,2-dihydropyridazine-3,6-dione 4e,f, respectively by heating each in PEG-600 at 100°C for 3-3.5 hr in high yields and in high purity, involving a dehydrative ring closure. The final compounds 4a-f have also been prepared alternatively by reacting 1 with 2 in PEG-600 at 100°C for 3.5-4 hr.
- Rafeeq,Srinivasa Reddy,Venkata Ramana Reddy,Naidu,Dubey
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p. 412 - 417
(2015/03/31)
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- Design, synthesis, and bioactivity study of novel benzoylpyridazyl ureas
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A series of novel benzoylpyridazyl ureas were designed and synthesized from maleic anhydride and hydrazine monohydrate. These benzoylureas were identified by 1H NMR spectroscopy and element analysis. The bioactivities of the new compounds were evaluated. These compounds exhibited larvicidal activities against oriental armyworm, and in particular, compound 13 displayed comparable activity to the commercial insecticide Hexaflumuron. Most of these compounds also had some larvicidal activities against mosquito. Interestingly, some compounds showed good plant growth regulatory activities.
- Ranfeng,Zhang, Yonglin,Fuchun,Wang, Qingmin
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experimental part
p. 6356 - 6361
(2010/07/05)
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- CHEMILUMINESCENCE MECHANISM OF CYCLIC HYDRAZIDES SUCH AS LUMINOL IN AQUEOUS SOLUTIONS.
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Independently of the mode of oxidation, the first critical intermediate on the chemiluminescent pathway of luminol is a hydroperoxide. Below its pK//a it decomposes into oxygen and the parent hydrazide. At higher pH, the monoanion of the hydroperoxide expels nitrogen and yields a monoprotonated dicarboxylate. The latter is chemiexcited to some extent.
- Lind,Merenyi,Eriksen
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p. 7655 - 7661
(2007/10/02)
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- 4,5-Dichloroimidazole-2-carboxylic acid derivatives
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4,5-Dichloroimidazole-2-carboxylic acid derivatives of the formula STR1 in which the group STR2 represents a carbon atom which has three bonds to hetero-atoms, and their salts with bases, possess insecticidal, acaricidal, fungicidal, nematicidal and herbicidal properties.
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