Chalcone analogues

Rurack, K. et al., Chalcone-analogue dyes emitting in the near-infrared (NIR) influence of donor-acceptor substitution and cation complexation on their spectroscopic properties and x-ray structure, J. Phys. Chem. A, 104, 3087, 2000. 

For example, treatment of l-(2-hydroxyphenyl)-3-arylpropenones 9 with o-PDA 1 carried out in dimethyl sulfoxide in the presence of sodium acetate under microwave irradiation produces dihydrodiazepines 10 in good yields [10] (Scheme 4.3). Chalcone analogues of dihydroacetic acid 11, as well, containing an 6>r /z0-hydroxyl group, react with 0-PDA in boiling ethanol to produce dihydrobenzodiazepines 12 [11, 12]. 

Reaction of the chalcone analogues of dehydroacetic acid with o-aminothiophenol provided a convenient route to 1,5-benzothiazepines <05T6642>. Bis ring fused thiazepines have continued to attract attention including the dihydropyrido[3,4-6]benzo[/][l,4]thiazepin-1-one 195, which was prepared from 193 via 194, and the dione 199 from 196 via 197 and 198<05TL2919>. 

Mass Spectrometry. The mass spectra of thiophen-2- and -3-carboxanilides, of thiophenic chalcone analogues, of 2,5-diaryl-substituted thiophens, of a terthienyl, and of some chromium tricarbonyl complexes have all been studied. 

Haloperidol cytotoxicity and its relation to oxidative stress 13MRM1993. Heterocyclic chalcone analogues as potential anticancer agents 13AAM422. Keto and exomethylene pyranonudeosides as antitumor agents 12MRM 255. 

The n.m.r. spectra of a number of mono- and di-substituted selenophens have been analysed and the chemical shifts discussed in additivity terms. An A%ray analysis of racemic 4,4 -dicarboxy-2,2, 5,5 -tetramethyl-3-3, -biselenienyl has been carried out. Dipole moments and u.v. spectra of chalcone analogues containing a selenophen ring have been studied. 

Enantioselective epoxidation of a chalcone analogue (75) and t-BuOOH with 10 mol% of (72) gave trans-(2R,3S -(76) in up to 80% ee. Soluble polyethylene glycol (PEG)-bound catalyst (73) was also developed to recover and reuse the ligand for Michael and epoxidation reactions, but the enantioselectivity was low despite the high yield. 

Table 1. Crystal forms, melting points, and vOH values of inclusion complexes with chalcones and analogues as guest molecules...

An array of 25 600 analogues of 49a was prepared from 80 chalcones, 20 amino acids, and 16 isatins <1998T4085>. 

ABE, I., MORITA, H NOMURA, A., NOGUCHI, H., Substrate specificity of chalcone synthase enzymatic formation of unnatural polyketides from synthetic cinnamoyl-CoA analogues, J. Am. Chem. Soc., 2000,122,11242-11243. 

The imine 217, formed from acetophenone and the 1-aminoimidazole, has been transformed into the enamine 218 which is then cyclized to 219 in trifluoroacetic acid (TFA) (Equation 40) <1995SC3271 >. The diaminoimidazole 220 reacts with ynone 221 to form 222 (Equation 41) <1998CHE1189>. Bromochalcones and chalcone dibromides can also be used in place of the ynone. Similar reactions have been used to prepare the dihydro analogues of 222 <1999CHE1207>. The reaction between 1-aminoimidazoles and 1,3-diketones has been extended to prepare bis-heterocyclic compounds, for example, 223 as ligands for transition metals (Equation 42) <2005EJI4382>. 

In effect, antimalarial trojan horse drugs of this type should deliver a double blow to the parasite by exploiting the presence of high concentrations of ferrous ion present in the parasite food vacuole as the trigger for protease inhibitor release. In model studies with prototype 81d, in the presence of ferrous ions, these systems readily degrade to produce the desired chalcone (82b, R = H, in 45% yield from 81d), in tandem with secondary carbon-centred radical 82a (Scheme 29). Furthermore, analogues 81d-f have superior in vitro antimalarial activity to that of arteflene (<25 nM in vitro versus Plasmodium falciparum, arteflene >50 nM). The other product obtained is the diol (82c), a product of two-electron reduction of the endoperoxide bridge. 

Reactions of diazomethane with various a,(3-unsaturated ketones were described in [27, 28]. For instance, Mustafa and Freifel [27] showed that treatment of chalcones 5 with ethereal diazomethane under normal conditions affected addition to the double bond of the ketone, forming pyrazolines 6 (Scheme 2.2). Alternative directions leading to heterocycles 7 as well as to methylation of the hydroxyl group were not observed. Similar results were described in [28]. On the other hand, Aleksandrova et al. [29] reported the formation of 4-aryl-3-(2-furoyl)-2-pyrazolines 9 when furyl analogues of chalcones 8 react with diazomethane. 

The hypothesis about the formation of compounds like B was also proven by other authors [35, 36]. For example, the Padmavathi et al. [36] studied the reactions of heterocyclic analogues of chalcones 14 obtained from the appropriate diaroylacetones 13 and diazomethane (Scheme 2.5). It was shown that this treatment gives a solid which was identified as (4 -aryl-4/,5 -dihydro-l/Ff-pyrazol-3 -yl)-(4-aryl-l/f-pyrrol-3-yl)methanone 15. 

Most of the publications on the reactions of malonic acid derivatives are devoted to the reaction of a,(3-unsaturated carbonyls with malononitrile 107. In this book we do not describe the results of all known publications but only the most characteristic or interesting ones in our opinion. The reactions of unsaturated ketones with malononitrile are usually carried out in methanol or ethanol in the presence of ammonium acetate [102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117]. Treatment of malononitrile 107 with chalcone 5 [115] and its heterocyclic analogue 109 [104] yielded 3-cyanopyri-dines 108 and 110 (Scheme 3.33). 

Reactions of a,(3-unsaturated ketones with various aminoazines are also described in the literature. Treatments involving 6-aminouracils and chalcones or their analogues are the most investigated among them [229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241]. 

According to [231, 232], the reactions of 6-aminouracil 294 with chalcones in air lead to pyrido[2,3-d]pyrimidines 296, while their dihydro analogues can be... 

The influence of the electronic character of substituents in the acetophenone part of the unsaturated ketones was not studied in [241], but results reported in [240], devoted to the reactions of 6-aminouracil and 2-thio-6-aminouracil with benzimidazole analogues of chalcones 303, showed that increasing the electron-withdrawing... 

As mentioned many times above [11, 12, 13, 36] heterocyclic analogues of chalcones can be used to synthesize dihydrodiazepines. In [42, 43] it was reported that open-chain 24 and cyclic 26 a, 3-unsaturated ketones were introduced into the treatment with o-PDA to obtain seven-membered heterocycles 25 and 27, respectively (Scheme 4.8). 

Synthesis of annelated diazepines based on unsaturated aromatic diazepines may involve the preliminary transformation of ketones into the corresponding l,3-diaryl-2,3-dibromopropane-3-ones (chalcone dibromides). The interaction between o-PDA or some of its substituted analogues with chalcone dibromides leads to the formation of aziridine derivatives [64] (see Chap. 1). However, in the case of 4-nitro-o-PDA, either azirenoquinoxalynes 53 or benzodiazepine derivatives 54 may be obtained depending on the reaction conditions [65] (Scheme 4.15). Diazepine derivatives 56 are obtained by the condensation of chalcone dibromides 51 with 5,6-diamino-1,3-dimethyluracil 55 [66], but aziridine derivatives are not isolated in this reaction. It should be noted that compounds 54 and 56 are formed owing to cyclization of the intermediate (3-enaminoketones [65, 66, 67] and are easily isolated from the reaction mixture. 

As noted already, the reactions of oc,(3-unsaturated ketones with or /zo-diamines are often accompanied by various rearrangements and side processes. For instance, the o-PDA condensation with chalcone in the presence of an acid catalyst or during overheating of the reaction mixture produces a final product of 2-phenylbenzimidazole [2, 7] a similar phenomenon is also observed for 2,3-diaminopyridine [54]. Owing to the existence of much more suitable approaches to the synthesis of 2-aryl derivatives of benzimidazole and their heteroannelated analogues (e.g., proceeding from diamines and acids or aldehydes [121]), such a trend in the interaction of chalcones with diamines is unlikely to have any application for this purpose. 

This intense sweetener is made from grapefruit skins and it has a liquorice-like sweet taste. NHDC (9) has long been suggested as a potential intense sweetener but has only recently received legislative approvals. It is 900 times sweeter than sucrose, and chemically NHDC is the open chain analogue of neohesperedin a flavonone which occurs in Seville (bitter) oranges (Citrus aurantum). The dihydrochalcones are flavonoids which are ubiquitous in plants flavonones, chalcones and anthocyanins are also flavonoids. 

Insuasty B, Tigreros A et al (2010) Synthesis of novel pyrazolic analogues of chalcones and their 3-aiyl-4-(3-aryl-4, 5-dihydro-lH-pyrazol-5-yl)-l-phenyl-lH-pyrazole derivatives as potential antitumor agents. Bioorg Med Chem 18 4965 974... 

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