Synthesis of new functional derivatives of pyrazolidine from 1-acetyl-3-methyl-5-nitromethyl-2-phenylpyrazolidine

Abstract

3-Nitromethylpyrazolidine reacts with derivatives of unsaturated acids and reducing agents with the formation of polyfunctional compounds of the pyrazolidine nucleus.We previously found a new method of directly introducing CH-acid radicals into the pyrazolidine molecule [1] on the surface of adsorbents without a solvent. Among others, a method of synthesizing pyrazolidine 5-nitromethyl derivatives was developed. In the present work further conversions of 1-acetyl-3-methyl-5-nitromethyl-2-phenylpyrazolidine (1) have been studied using the reactivity of both the methylene and the nitro groups.In [1] conditions were found for the synthesis of nitro derivative 1 with a cis:trans isomers ratio of 1:4. After a small change to the method we succeeded in obtaining a diastereoselective course for the process on neutral aluminum oxide and the isomer ratio of compound 1 was ~1:100 according to data of 1 H NMR spectra. In this way we obtained predominantly one diastereomeric pair of trans structure. Attempts to introduce the obtained nitro derivative 1 into a Michael reaction with derivatives of unsaturated acids under the usual conditions with a basic catalyst (triethylamine) were unsuccessful. In view of our positive experiment using the method of carrying out the reaction on the surface of an adsorbent without a solvent [1], we carried out a series of trial experiments and discovered that the Michael reaction with acrylonitrile proceeds best of all at room temperature on basic aluminum oxide containing 20% adsorbed KF. After 48 h the initial compound 1 reacted completely with the formation of product 2 by addition of two molecules of acrylonitrile. N N Me Ac Ph NO 2 N N Me Ac Ph O 2 N R R N N Me Ac Ph O 2 N R R 1 + 2, 3a 3b,c 1 2 R = CN; 3a-c R = COOMe; b R 1 = H; c R 1 = Me __________________________________________________________________________________________ 1 Moscow M. V

A new approach to the synthesis of aliphatic triamines and diamino alcohols that are analogs of the anti-TB drug ethambutol

“…The combined extracts were concentrated and sepa rated by column chromatography on SiO 2 in chloroform-meth anol (100 : 1 → 1 : 1). 16; 27 mg, 0.1 mmol) was dissolved in ethanol (0.27 mL) and Raney nickel (1 g) was added. Then hydrazine hydrate (100 μL) was added dropwise with stirring for 2 h. After 3 h, K 2 CO 3 (100 mg) and benzene (0.2 mL) were added.…”