5-(1-Alkenyl)-1, 3, 4-oxadiazol-2(3H)-one

3-(2-alkenoyl)-thiocarbazic acid O-methyl esters 1 are desulfurated by bromine and the unknown intermediates are transformed by alkali to 5-(1-alkenyl)-1, 3, 4-oxadiazol-2(3H)-ones ( 2 ). This type of oxadiazolone substitution is not realizable by the common ring closure of hydrazides with phosgene due to pyrazolidinone ring closure of unsaturated acids with hydrazine.     

Enamine Configuration of 5-Methyl-2-phenyl-4-[（Z）-3-tolylamino-phenylmethylene]pyrazol-3（2H）-one

1 INTRODUCTION In contrast to the old-line academic and practical studies of 1-phenyl-3-methyl-4-benzoyl-5-pyrazo- lone (PMBP) on the metal coordination chemistry[1], the complexes of β-ketoamines derivated from PMBP received little attention due to its complicated com- plexation. However, in recent years, there has a sudden growth of this area as a result of its timely interest in biological activities[2]. Recently, a series of β-ketoamines[3] containing PMBP have been prepared fro…     

A novel biomimetic route to the 3-acyl-5-hydroxy-3-pyrrolin-2-one and 3-acyl-3,4-epoxy-5-hydroxypyrrolidin-2-one ring systems

Modified Moffat oxidation of alcohols 17, 22, and 25 afforded aldehydes that underwent intramolecular aldol reactions on treatment with a NaOH solution to yield 4-pyrrolin-2-ones 16, 23, and 26. Oxidation with DMDO at -40 degrees C provided 3-acyl-5-hydroxy-3-pyrrolin-2-ones 18, 24, and 27 with the ring system of oteromycin (3), UCS1025A (5), and related natural products. Further oxidation of 18 yielded 3-acyl-3,4-epoxy-5-hydroxy-pyrrolidin-2-one 19 with the ring system of fusarin C (1) and epolactaene (2). Dehydration of 18 afforded 20 with the talaroconvolutin A (4) ring system.     

Thermal transformations of B10H12(NH3)2, B10H12(C5H5N)2, and B10H12(C9H7N)2

Conclusions For B₁₀H₁₂L₂, where L=NH₃, C₅H₅N, or C₉H₇N, features of thermal transformations in the range 25–850°C and the composition of the pyrolysis products are determined. The latter are x-ray amorphous phases, containing nitride, carbide, boron carbide, boron, and carbon.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2481–2484, November, 1988.     

4-(3,4-二甲氧基苯基)-5-硝基哌啶-2-酮的合成

以3-(3,4-二甲氧基苯基)-4-硝基丁酸甲酯(4),氨水和甲醛为原料,异丙醇溶液为溶剂,经曼尼希-酯胺解偶联反应合成了新化合物4-(3,4-二甲氧基苯基)-5-硝基哌啶-2-酮,其结构经1H NMR,13C NMR和EI-MS表征。在最佳反应条件{4 1.0 mmol,n(4)∶n(27%氨水)∶n(37%甲醛)=1.00∶1.30∶1.05,异丙醇[V(异丙醇)∶V(水)=5∶1]7.5 m L,于100℃反应12 h}下,收率74.1%。     

Concise Synthesis of Ring-Fission Metabolites of Epicatechin: 5-(3,4-Dihydroxybenzyl)dihydrofuran-2(3H)-one M6

The ring-fission metabolites of epicatechin, 5-(3,4-dihydroxybenzyl)dihydrofuran-2(3H)-one M6 and 3-methylated M6, were prepared from 3,4-dihydroxybenzaldehyde and furan-2(5H)-one using two new concise methods in excellent yields (three or two steps in 40–60% overall yield).