The Reaction of N-Aryl-C-ethoxycarbonylnitrilimine with Olefins

Abstract

C-Ethoxycarbonylnitrilimines treated with monosubstituted olefins predominantly gave 5-substituted 3-ethoxycarbonyl-2-pyrazolines. From the analysis of the relative rate and regioselectivity of a variety of monosubstituted olefins for the cycloaddition, the nitrilimine is shown to have reactivity and regioselectivity similar to the throughly studied diphenylnitrilimine. The cycloaddition regioselectivity is discussed in terms of frontier orbital energies and coefficients.

Synthesis of spiro-pyrazole-3,3′-thiopyrano[2,3-b]pyridines and azolo[a]pyrido[2′,3′:5,6]thiopyrano[3,4-d]pyrimidines as new ring systems with antifungal and antibacterial activities

“…42 spectrum of compound 2a, was observed at δ 5.01 in the reaction product, which is consistent with an sp 3 CH-proton. The latter chemical shift is consistent with the pyrazoline-4H proton and not with the pyrazoline-5H-proton which appears at lower chemical shift [12,13]. Also, the 13 C NMR spectrum of compound 6a revealed three sp 3 carbon signals at δ 36.87, 50.90 and 76.53.…”

“…In addition, many investigations concerning the synthesis of spiro heterocycles utilizing nitrilimines were discussed [4][5][6][7]. We have previously described several routes to fused polyheterocyclic ring systems [8][9][10], we here intend to report our results on the synthesis of the so far unreported 3-benzylidene-4oxothiopyrano [2,3-b]pyridines 2a,b and their 3-(N,Ndimethylamino)-methylene analog 3 as well as their applications in the synthesis of the novel spiro-pyrazolo-3,3'thiopyrano [2,3-b]pyridines 6a,b, 6H-2-phenylpyrazolo [1,5-a]pyrido [2',3':5,6]thiopyrano [3,4-d]pyridine (12) and 7H-pyrido[2",3":6',5']thiopyrano [4',3':4,5]pyrimido-[1,2-a]benzimidazole (14) as new ring systems. The biological activities of the obtained products were investigated and some of them showed high antifungal and antibacterial activities.…”

Synthesis and antimicrobial evaluation of some new pyrazole, pyrazoline and chromeno[3,4-c]pyrazole derivatives

“…This is because compounds of type 17,18 are expected to exhibit strong nitrile absorption in their IR spectra 37 and their methine chemical shift at the 5-position would appear at upper field (5.1 ppm). 38 The decisive evidence for the existence of the nitrile group is provided by the 13 …”

A bicyclo[3.1.1]heptano[4,3-c]pyrazole derived chiral auxiliary for dipolar cycloadditions

“…Spectroscopic data of the latter products ( 1 H NMR) are in full agreement with those of 5-substituted-4,5-dihydropyrazoles. 10 Major cycloadducts 11 and 13 were obtained chemically and enantiomerically pure through silica gel column chromatography, in good isolated yields. The absolute configuration of the newly formed stereocentre of major diastereoisomers 11 and 13 was determined by means of chemical correlation experiments.…”