A reaction of 6‐amino‐1,3‐dimethyluracil with 3‐(hetero)aroylacrylic acids and their methyl esters leads to hexahydropyrido[2,3‐d]pyrimidine‐5‐carboxylic acids or the corresponding methyl esters in high to excellent yields. One‐pot oxidation of the acid derivatives with CAN is accompanied by decarboxylation to give tetrahydropyrido[2,3‐d]pyrimidines, while oxidation with bromine resulted in the formation of tetrahydropyrido[2,3‐d]pyrimidine‐5‐carboxylic acids. The aromatization of methyl hexahydropyrido[2,3‐d]pyrimidine‐5‐carboxylates was achieved by K2CO3‐mediated air oxidation under ambient conditions.

The reaction of aroyl[bis(4 hydroxycoumarin 3 yl)]methanes with 1,2 phenylenediamines in Pr i OH is accompanied by the recyclization to 8 R or 7 R 4 (2 hydroxyphenyl) 1,5 benzodiazepin 2 ones, whereas the reaction with o phenylenediamine and its 4 methyl sub stituted derivatives in MeOH produces organic ionic salts of the bis coumarin anion with monoprotonated o phenylenediamine as the cation.Key words: aroyl[bis(4 hydroxycoumarin 3 yl)]methanes, 4 R 1,2 diaminobenzenes, 8 R (7 R) 4 (2 hydroxyphenyl) 1,5 benzodiazepin 2 ones, recyclization, ionic salts, X ray diffraction study.Various 4 hydroxycoumarin derivatives have found use as drugs. 1-5 Among these is neodicoumarin (ethyl di(4 hydroxycoumarin 3 yl)acetate), which is used in medicine as an anticoagulant. 6 These bis adducts based on heterocyclic CH acids and active carbonyl compounds (aldehydes or glyoxals) have attracted interest because their molecules contain several electrophilic centers, thus giving promise that various heterocyclization path ways are possible in the reactions with binucleophilic re agents.Earlier, 7 we have demonstrated that the reaction of aryl(aroyl)[bis(5,5 dimethyl 1,3 dioxocyclohexan 2 yl)]methanes with o phenylenediamine (o PDA) produces hexahydrobenzo[b,e] 1,4 diazepin 1 one derivatives 1A or 9 aryl(aroyl) 10 (2 aminophenyl)decahydroacridine 1,8 dione derivatives 2 depending on the electronic char acter of the substituent in the aryl or aroyl fragments. Electron withdrawing substituents in the aromatic moi ety facilitate the formation of the diazepine ring, whereas the formation of acridones is typical of the starting polyketones containing electron releasing substituents in the benzene ring.In the present study, we investigated the reaction of 4 R benzoyl[bis(4 hydroxycoumarin 3 yl)]methanes 3a-c with o PDA (4a) and its substituted derivatives 4b-d with the aim of synthesizing diazepines 1B, which are structurally similar to diazepines 1A and in which the diazepine fragment is annulated with the coumarin ring. The starting ketones 3a-c were synthesized in good yields by heating 4 hydroxycoumarin with p substituted aryl glyoxals in AcOH for a short period of time. Their struc tures were confirmed by 1 H NMR spectra, which show singlets for the methine protons at δ 6.2-6.4 and multi R = Ar, COAr

In cyclic 1,5-diketones the position of the carbonyl groups determines exclusively the ease of their cyclization and makes them as convenient basis for the synthesis of nitrogen-, oxygen-, and sulfur-containing heterocycles [1,2].The aim of the present work is the study of the reactivity of the Michael adducts 1a-j [3,4], obtained from dimedone and aromatic aldehydes or furfural (adduct 1j), in relation to the bidentatic nucleophiles o-phenylenediamine 2 and o-aminophenol 3. The cyclic tetraketones 1a-j exist in the enolic form which makes them structurally close to α,β-unsaturated ketones, the reactivity of which in relation to 1,4-dinucleophiles has been studied previously [5,6].The electronic character of the substituents in R influence the direction of the interaction of compounds 1a-i with o-phenylenediamine 2 on boiling these reactants in 2-propanol (method A). The corresponding hexahydrodibenzodiazepinones 4a-f were obtained from tetraketones 1a (R = Ph) and 1b-f (electronwithdrawing substituents in R: 4-F, 4-Cl, 4-Br, 4-NO 2 ).When electron-donating substituents (4-OMe, 4-NMe 2 , 2-OH) are present in R, as in compounds 1g-i, either decomposition of the latter takes place (in the case of tetraketones 1g,h) with the formation of the corresponding azomethines 5a,b, or conversion into decahydroacridinedione 6 occurs (from tetraketone 1i). Hexahydrodibenzodiazepinone 4j is obtained from hetaryl-substituted tetraketone 1j (R = 2-furyl).Tetraketones 1a-d,g,h do not react with o-aminophenol 3 under the conditions mentioned above (method A). Only on boiling these reactants in DMF the interaction products, decahydroacridinediones 7a-f, were obtained in good yield.The results obtained enable the interaction of compounds 1 with binucleophiles 2 and 3 to be represented in the following way.

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