Condensation-cyclization of diketones and keto esters with electron-deficient aromatics. I. Formation and structure of some stable delocalized anions containing the bicyclo[3.3.1]nonane skeleton

Abstract

Anions Containing the Bictclo [3.3.1 ]nonane Skeleton 383 parison of the downfield shifts observed in the bisected geometry A (2, 1.1, and 3, 0.8 ppm) and in the unsymmetrical geometry B (8, 0.1-0.5 ppm) provides direct support for the proposition that ground-state cyclopropyl ketone delocalization is maximized in the bisected conformation.An examination of the relevant data for the unsymmetrical vinylcyclopropane 9 (see Table II) leads to conclusions analogous to those obtained for carbonyl group conjugation. There is no evidence to support selective overlap of the C2-C8bond. Since an accurate estimate of the carbon-carbon double-bond anisotropy and other nonconjugative effects on the proton resonances due to the presence of two sp2hydridized carbons in 9 is more tenuous, these tentative conclusions concerning the geometric parameters for vinylcyclopropane participation require further support. Experimental SectionNmr spectra were obtained on a Varían Associates Model HA-100 spectrometer; infrared spectra were measured on a Perkin-Elmer Model 237 or 257 grating infrared spectrometer. Nortricyclene (2h) was prepared by the method of Schleyer.18The cyclopropyl hydrogen-carbon-13 coupling constant of Vuch =' 175 Hz was measured.20(19) P. von R. Schleyer, J. Amer. Chem. Soc., SO, 1700 (1858).Ttortricyclanone (2c) was prepared by the method of Meinwald.8 The *Jhch for the Ha position was 184 Hz and for the H/s position 185 Hz.20 The chemical shifts of the , H#, and ezo-CHa-(1.65 ppm) protons remained constant (±1 Hz) on going from a neat sample to a 2.5% CC14 solution. The C4 H8 and the endo-CH2~(1.97 ppm) protons were shifted ca. 8 and 4Hz, respectively, upon dilution.3-Methylenetricyclo [2.2.1.02•6]heptane (2m) was prepared from nortricyclanone (2c) using the Corey21 modification of the Wittig reaction. The crude product was purified by chromatography on silica gel using pentane. Distillation furnished pure 2m: bp 113-114°; average yield of three runs ca. 16%; ir (CC14) 1684 cm-1; nmr (CC14), 4.48, 1 H (singlet), 4.60 ppm, 1 H (d, / ~1 Hz) (see Table I).Tricyclo [3.3.0.02 8] octane (8h) was prepared from ketone 8c14 using the Huang-Minlon adaptation of the Wolff-Kishner reduction.22 The crude product was purified by preparative vpc to give hydrocarbon 8h:23 mol wt (mass spectrum) 108; nmr (CC14), 1.17-1.65 (6 H, complex), 1.65-2.05 ppm (5 H, complex) (see Table II).

Synthesis of tricyclic systems on the basis of σ-adduct of 3,5-dinitropyridin-2-ol with acetone

“…We briefly reported in [7] that successive nucleophilic addition of acetone dicarbanion to 3,5-dinitropyridin-2-ol and double Mannich condensation yield tricyclic compounds containing a 3,7-diazabicyclo[3.3.1]nonane fragment. In continuation of these studies, in this work we examined in detail the product structure by two-dimensional high-resolution NMR techniques and X-ray analysis and synthesized a series of new 6-substituted 4,8-dinitro-2,6-diazatricyclo-[6.4.0.0 4,9 ]dodecane-3,11-diones from various primary amines. Initial 3,5-dinitropyridin-2-ol (1) was prepared according to the procedure described in [8] by nitration of pyridin-2-ol.…”

“…Initial 3,5-dinitropyridin-2-ol (1) was prepared according to the procedure described in [8] by nitration of pyridin-2-ol. 6-Substituted 4,8-dinitro-2,6-diazatricyclo[6.4.0.0 4,9 ]dodecane-3,11-diones 2a-2i were synthesized in two steps (Scheme 1). In the first step 3,5-dinitropyridin-2-ol (1) in acetone solution was treated with piperidine as base to obtain light brown crystalline bicyclic anionic adduct A.…”

“…In the first step 3,5-dinitropyridin-2-ol (1) in acetone solution was treated with piperidine as base to obtain light brown crystalline bicyclic anionic adduct A. The formation of analogous adducts was observed in reactions of 1,3,5-trinitrobenzene [9] and 3,5-dinitropyridine derivatives [10] with ketones in the presence of secondary and tertiary amines. A cold mixture of formaldehyde and primary amine in aqueous ethanol was then added DOI: 10.1134 to the resulting σ-adduct, and the mixture was acidified with glacial acetic acid.…”

“…The HSQC data allowed us to unambiguously identify signals from 500 Structure of the molecule of 6-(3,4-dimethylbenzyl)-4,8-dinitro-2,6-diazatricyclo[6.4.0.0 4,9 ]dodecane-3,11-dione (2g) according to the X-ray diffraction data. C 1 (δ C 53.34 ppm) and C 9 (δ C 41.95 ppm) which displayed direct 13 C-1 H couplings.…”

“…In summary, we have developed a preparative procedure for the synthesis of 6-substituted 4,8-dinitro-2,6-diazatricyclo[6.4.0.0 4,9 ]dodecane-3,11-diones by nucleophilic addition of acetone dicarbanion to 3,5-dinitropyridin-2-ol and subsequent double Mannich condensation of the bicyclic adduct.…”