Truong Hong Hieu

Domino synthesis of the first representative of a dibenzo(perhydropyrimidino)aza-14-crown-4-ethers series

The successful use of thiocarbamide in a domino synthesis of azacrown ethers containing a perhydrotriazine fragment in the macrocycle has been reported in [1]. However, carbonic acid diamide (urea) does not form the target azacrown ether in a similar cyclocondensation with 1,5-bis(2-formylphenoxy)-3-oxapentane (1) and ammonia. Continuing our work on the synthesis of azacrown ethers with perhydroazine fragments as subunits [1-5] we have studied the three-component condensation of the podand 1 with malonic acid diamide (2) and ammonia. We have proposed that, in this case, the intermediate product of condensation of dialdehyde 1 with the CH2 group of the diamide 2 arising in the cascade condensation reaction indicated above can activate one of the amide groups for a tandem cyclocondensation. This leads, for the first time, to the preparation of the (perhydropyrimidino)azacrown ether 3 which is the first example of a previously unknown type of crown ether. In fact, carrying out the condensation of the indicated components 1, 2, and ammonium acetate in the ratio 1:3:10, respectively, gave the (pyrimidino)azacrown ether derivative 3 which was separated from the reaction mixture in 45% yield by crystallization. Its structure was confirmed by chromato-mass spectrometric and H and C NMR spectroscopic data.

One-stage synthesis of 1,4-bis(8,11,14-trioxa-25-azatetracyclopentacos-23-yl)benzene

1,4-bis(8,11,14-trioxa-25-azatetracyclopentacos-23-yl)benzene, terephthalaldehyde conden-sation with 1,5-bis(2-acetylphenoxy)-3-oxapentane and ammonia. In the publications [1-6] methods have been reported for the preparation of azacrown ethers containing hydrogenated derivatives of various heterocycles (e.g. piperidine [1, 2], azabicycloalkane [3], tetrahydropyran [4], bispyridine [5], or perhydrotriazine [6]) in the macrocycle. Continuing our work on developing novel methods for the preparation of azacrown ethers we have studied the possibility of constructing a heterocyclic system which includes two (pyrido)azacrown ether fragments separated by a benzene spacer. With the aim of preparing similar ditopic macromolecues we have carried out a three-component condensation of the 1,5-bis(2-acetylphenoxy)-3-oxapentane (

9-[(2-Hy-droxy-benzyl-idene)amino]-11-(2-hy-droxy-phen-yl)-10,13-diphenyl-8-oxa-12-azoniatricyclo-[7.3.1.0]trideca-2(7),3,5-triene acetate ethanol disolvate.

The title compound, C36H31N2O3 +,C2H3O2 −·2C2H5OH, the product of a domino condensation of dibenzyl ketone with salicylic aldehyde and ammonium acetate, crystallized as the ethanol disolvate. The cation of the salt comprises a fused tricyclic system containing three six-membered rings (piperidine, dihydro-2H-pyran and benzene). The piperidine ring has the usual chair conformation, while the dihydropyran ring adopts a slightly distorted sofa conformation. In the crystal, there are six (one intra- and five intermolecular) independent hydrogen-bonding interactions: the intermolecular hydrogen bonds link the cations and anions and ethanol solvent molecules into ribbons along [001]. The ribbons are stacked along the a axis.