Triazole derivativesTriazole derivatives R 0280 Synthesis and Investigation of Tuberculosis Inhibition Activities of Some 1,2,3-Triazole Derivatives. -Condensation of α-diazo-β-oxoaldehydes (I) with different amines (II) affords the title compounds in good yields. -(DABAK*, K.; SEZER, O.; AKAR, A.; ANAC, O.; Eur. J. Med. Chem. 38 (2003) 2, 215-218; Dep. Chem., Fac. Sci., Tech. Univ. Istanbul, TR-80626 Maslak, Istanbul, Turk.; Eng.) -M. Paetzel 24-107
Carbonyl ylides arising from ethyl acetodiazoacetate/dimethyl diazomalonate and a,b-enones with mainly s-cis conformations underwent disrotatory cyclization to produce dihydrofuran derivatives. This process proved to be sensitive to steric effects. The corresponding ylides arising from rather s-trans a,b-enals yielded dioxole derivatives. The mechanisms of the reactions are discussed.Introduction. ± Furan derivatives are among the most-significant heterocycles in natural products, and, consequently, a wide range of methods for their syntheses has been developed [2]. In relation to dihydrofuran synthesis, we previously reported the reactions of three b-monosubstituted (E)-enones (a-and b-ionone, and benzalacetone) with two diazobis(carbonyl) compounds (dimethyl diazomalonate (DMDM) and ethyl acetodiazoacetate (EADA)) in the presence of copper(II) acetylacetonate ([Cu-(acac) 2 ]) [1]. Those enones definitely adopt s-cis conformations in their ground states. The results of that former work are summarized in Table 1 and showed interesting selectivities concerning both product distribution (initial dihydrofuran formation vs. furofuran formation) and diastereoselectivity in dihydrofuran formation 2 ). It was mostly the product distribution that led us to further studies on this subject.The only previous reports directly related to our work came from Spencer and coworkers [3 ± 5]. They showed that in the case of a few cyclic a-methoxymethylene ketones, in which the carbonyl and olefin moieties are fixed in a s-cis arrangement, reactions with ethyl diazoacetate (EDA) had given furancarboxylates in moderate yields via carbonyl ylides after MeOH elimination. The configuration at alkenyl CC bonds was not mentioned in their reports. On the other hand, Alt and Maas, and Huisgen and March have shown that it is possible to trap carbonyl-ylide adducts intermolecularly from the reactions of unsaturated aldehydes with some a-diazo-a-(trimethylsilyl)acetates [6 ± 8], although they did not observe 1,5-cyclization reactions of carbonyl ylides.Our focus in the present work has been the nature of the ring closure of the carbonyl ylides. The formation of the dihydrofuran derivatives in the first-step reactions should be realized by way of a 1,5-cyclization process of the related carbonyl ylides. At this
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