Benzhydrazides

A direct catalytic conversion of esters, lactones, and carboxylic acids to oxazolines was efficiently achieved by treatment with amino alcohols in the presence of the tetranuclear zinc cluster Zn4(0C0CF3)60 as catalyst, essential for condensation and cyclodehydration reactions. For example, the use of (5)-valinol allowed the easy synthesis of oxazolines 125 and 126 in satisfactory yields <06CC2711>. A one-pot direct preparation of various 2-substituted oxazolines (as well as benzoxazoles and oxadiazoles) was also performed from carboxylic acids and amino alcohols (or aminophenols or benzhydrazide) using Deoxo-Fluor reagent <06TL6497>. 

Benzenediol, h86 Benzenemethanol, b78 1,2,3-Benzenetriol, t317 Benzenethiol, tl 56 Benzhydrazide, b71 Benzhydrol, d760 Benzhydrylamine, d761... 

The interaction of cyanogen bromide vapors with solid o-hydroxyaniline (236u) or the solid benzhydrazides 324 at room temperature provides the 2-aminobenzoxazole (433) or the 2-amino-5-aryl-aminooxadiazole salts 434 [92] (Scheme 68). These 3-cascades imply formation of the cyanamide, its cyclization, and tautomerization. 

Methodc Zu eincr Losung von 4,6 m/(0,038 mol) Kohlensaure-chlorid-trichlormethylesterin 30 ml 1,4-Dioxan fiigt man tropfenweise eine Losung von 6,8 g (0,05 mol) Benzhydrazid in 30 m/ 1,4-Dioxan bei 20 hinzu. Danach wird die Reaktionsmischung 4h unter RiickfluB erhitzt und das Losungsmittel i.Vak. abdestilliert. Der verbliebene Riickstand kristallisiert aus Wasser in farblosen Nadeln Ausbeute 7,3 g (90%) Schmp. 137-138°. 

So erhalt man bei der Reaktion von 4-Nitro-benzhydrazid mit (Chlor-methylthio-methylen)-piperidinium-chlorid entweder 5-(4-Niiro-phenyl)-2-piperidino- oder 2-Methylthio-5-(4-nitro-phenyl )-l, 3,4-oxadiazol2is ... 

Nitro-phenyl)-2-piperidino-l,3,4-oxadiazol248 9,1 g (50 mmol) 4-Nitro-benzhydrazid, 80 ml trockenes Pyridin und 12,0 g (56 mmol) (Chlor-methylthio-methylen)-piperidinium-chlorid erhit/t man 2 h auf 70°. AnschlieBend verdiinnt man mit 4%iger Natronlauge, filtricrt und kristallisiert aus Ethanol um Ausbeute 7,3 g (54%) Schmp. 176°. 

Mcthylthio-5-(4-nitro-phenyl)-l,3,4-oxadiazol248 87 g (480 mmol) 4-Nitro-benzhydrazid, 600 ml 1-Me-thyl-2-oxo-pyrrolidinund 130 g (608 mmol) (Chlor-methylthio-methylen)-piperidinium-chlorid erhitzt man 3 h auf 70°. Nach dem Abkiihlen wird mit verd. Natronlauge alkalisch gemacht. abgesaugt und die gelbe Substanz aus Ethanol umkristallisiert Ausbeute 90 g (79%) Schmp. 155°. 

Die thermische Cyclisierung von 2-Amino-benzhydrazid mit aromatischen Carbonsauren ist von Nebenreaktionen begleitet. Man erlialt in Abhangigkeil von den Substituenten 2-(2- Ami-no-phenyl)-5-aryl- bzw. 5-Aryl-2-(2-methylamino-phenyl)-l, 3,4-oxadiazole in Ausbeuten von 30-60%39°. 

Melting Points of Substituted Benzazides, Benzhydrazides, and Diphenylureas... 

It was obtd when phenyl cyanide p-nitro-benzhydrazide benzene sulfonate were heated at 200° for 3 hrs, cooled the crystalline melt extracted with cold NaOH soln the extract acidified with coned HO (Ref 2) and by other methods (Refs 3, 4, 6 8)... 

The polyamide-hydrazide 7 was prepared by solution polymerization in anhydrous dimethylacetamide from terephthaloyl chloride and p-amino-benzhydrazide at ca. 10 °C. The polyamide 8 resulted from the polycondensation of m-phenylenediamine with isophthaloyl chloride at —20 °C, whereas 9 was prepared by the reaction of terephthaloyl chloride with the complex diamine l,3-bis(3-aminobenzamide)benzene at —20 °C. The water flux and salt rejection through these membranes were summarized in Table 5. The polyamide-hydrazide (7) membranes were prepared from polymer solutions containing 6 7% polymer (Mv 3 34,000) by casting on glass plates. The material was placed in an oven for 30 60 min and coagulated in deionized... 

N 33.79% ndles (from ethanol) mp 166° (decompn). Sol in hot ethanol. Prepnis by reaction of an ethanolic soln of di-o-chloro-benzhydrazide chloride with Na azide for 30 hrs at RT. The product is filtered off, washed with w and ether and hydrolyzed with dil sulfuric acid. The compd explds mildly when heated rapidly on a spatula... 

Keywords solid benzaldehydes, benzhydrazide, isatin, waste-free, solid-solid reaction, acyl hydrazide... 

Benzhydrazide, b72 Benzhydrol, d677 Benzhydrylamine, d678 Benzhydryl bromide, b274 Benzidine, b 36... 

The 2-(4-carboxyphenyl)pyrazolo[3,4-d]-l,2,3-triazole (25c), considered to be useful in construction of a range of heterocycles with interesting fluorophores, underwent condensation with suitably substituted aryl amines (e.g., 2-aminophenol, 1,2-diaminobenzene, and benzhydrazide) to furnish, respectively, the extended heterocycles (25f,g,h) (Table 2) in good yield (Scheme 8)... 

Polyfluorinated target molecules are obtained when both building blocks are fluorinated and/or perfluoroalkylated. A typical example for this type of condensation is the synthesis of a tris(trifluoromethyl)-substituted 1,3,4-triazole from 3,5-bis(trifluoromethyl)benzhydrazide and trifluoroaceta-midine (78BRP1510647). 

Phenyl-1,3,4-thiadiazole (3, R = Ph) was first prepared by Ohta et al. by thioformylation of benzhydrazide with sodium dithio-formate, followed by dehydrating cyclization in sulfuric acid. In the same way the 2-benzyl and some aromatic analogs were obtained. Holmberg prepared 3 (R = Ph) by oxidation of l-methylene-2-thiobenzoylhydrazine (9) and of glyoxylic acid thiobenzhydrazone (10) with ferric chloride, and finally by reaction between thiobenz-hydrazide (11) and formic acid. 

Hiinig and Oette prepared azothiadiazoles (85) by oxidative coupling of 3-methyl-l,3,4-thiadiazolin-2(3)-one hydrazones (84) with phenols and diphenylamine. 84 was prepared by reaction of 2-methyl-thio-3-methyl-l,3,4-thiadiazolium ions (82) with benzhydrazide and hydrolysis of the first formed benzhydrazone (83). The coupling to 85 was performed with potassium ferricyanide in alkaline medium. 

Benzhydrazides in small quantities have been oxidized to the aldehydes with potassium ferricyanide in excess ammonium hydroxide (30-... 

N , Reactions with. The course of the reaction between diazomethane and hydrazoic acid was studied using N -labeled reactants. It was also found that labeled methyl azide could be reliably analyzed by decompn with HI, and that unambiguously N -labeled niethyl azide could be made by treating methylurea with HN 02 and decompg the product with KOH to CHjNN (Ref 2). Another study noted that in the course of the diazotization of benzhydrazide and 2,4-dinitrophenylhydrazine with HN 02, only azides of the structure R—N=N=N were formed (Ref 1)... 

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