Carbonyl and thiocarbonyl compounds. Part XIII. 2-Aroyl-1,3-benzodioxoles of potential pesticidal activity and their cleavage with hydrazines

Abstract

2-Aroyl-4,5,6,7-tetrahaiogeno-l,3-benzodioxoles (1 ) are readily obtained through the uncatalysed interaction between tetrahalogeno-o-benzoquinones and the corresponding a-diazo-acetophenone or -acetonaphthone. They behave differently from all other methylenedioxy-compounds previously investigated with respect to cleavage by nucleophilic reagents. They react with phenylhydrazine in boiling n-butanol affording the corresponding arylglyoxal bisphenylhydrazones (6) in high yields. However, they resist cleavage by benzoylhydrazine, by malononitrile, and by cyanoacetic ester under similar conditions. The reaction mechanism is discussed. The osazones obtained are cyclised readily by copper sulphate in aqueous dioxan, affording the corresponding 4-aryl-1 Presented before the

A Facile synthesis of 2-Methyl-1,2,3-Triazoles

“…Unexpectedly, 2-methyl-4phenyl-1,2,3-triazole (3a) was obtained. This suggested that the reaction process could be analogous to an earlier report, 10 and therefore we investigated α-bromoacetophenone as the starting material in reaction with methylhydrazine. The same product was afforded in 59% yield.…”

“…The general method for the synthesis of 1,2,3-triazole is the 1,3-dipolar cycloaddition of various azides (or salts thereof) with acetylenes, 7,8 activated methylene compounds, 3 or nitriles. 9 In particular, the intramolecular condensation of bisarylhydrazones has been a method of choice for the synthesis of 2,4-diaryl-1,2,3-triazoles [10][11][12] . In this paper we report a facile method to obtain a series of 2-methyl-1,2,3-triazoles (3) by cyclisation of α-bromoacetophenone with methylhydrazine.…”

1,2,3‐ and 1,2,4‐triazolium salts, pyrazoles, and quinoxalines from diarylnitrilimines and isocyanides: A study of the scope

“…The hydrazonoyl chlorides 1a,b,d-g [20] and the isocyanides 3b,c [21], 3d [22], 3e [23], and 3g-k [24] were prepared according to (or by adopting) literature procedures. Known products were identified by means of authentic samples and/or literature data, as were the 1,2,3-triazoles 7 a [25] and 7 b , c [26], the 1,2,4,5-tetrazine 9b [27], the 1,2,4-triazoles 13a [7] and 13b [13], the ureas 25 c [28], 25 d [29], 25 g [30], and 25 j [31], the 1,2,4triazoles 27a [32], 27d [33], and 27e [34].…”

Another Way to the Synthesis of 1,2,3‐Triazoles

“…Among them, 1,3‐dipolar cycloaddition between an azide and an alkyne is the classical and extensively used method [6–8], leading to the 1 H ‐[1,2,3]triazole derivatives. Other methods, such as the reaction of nitriles with CH 2 N 2 [9] and the intramolecular condensation of bisarylhydrazones [10–12], have not been developed further. The strict reaction conditions or monotonous products may be responsible for their unpopularity today.…”