Table of Contents

Abstract: n/a

Abstract: Four new ms-tetrasubstituted β-octaalkylporphyrins are synthesized and their spectral properties are discussed.

Abstract: The solubility in benzene and ethanol of 2,8,12,18-tetramethyl-3,7,13,17-tetrabuthylporphyrin with various substituents in the5,15-positions of the molecule is investigated. A comparative analysis of the influence of alkyl substituents on porphyrin solubility is carried out.

Abstract: The reduction and oxidation behaviour in alkaline solution of 3,7,13,17-tetramethyl-2,8,12,18-tetrabutylporphyrin (L) has been studied by cyclic voltammetry. The shape of I-E curves was investigated at different terminal values of electrode potential and at different scan rates. It was shown that it is possible to obtain two reversible one-electron electroreduction processes accompanied by the formation of mono- and dianion forms of the porphyrin under specific experimental conditions. The reduction potentials of the L↔L^- and L^-↔L^2- processes are –0.67±0.02 V and –1.12±0.02 V, respectively.

Abstract: The influence of NO₂, Br, and COOH function substituents in various positions of Cu(II)Pc on the reactivity of the latter concerning the dissociation of the metal - nitrogen bonds in proton donor solvents is discussed.

Abstract: The mutual influence of ligands within the structure of Zn-porphyrins on the thermodynamic stability of the latter was investigated.

Abstract: The existence of columnar mesophases (CM) for a new series of the porphyrin derivatives is predicted. With this purpose, the computation of molecular parameters (K, К_c, К_s, K_p, M_m, M_r) is carried out for eighty five molecules, including materials with a small number of peripheral substitutes. For verification of the existence of CM in the series of materials examined, some of them are synthesized and their mesomorphism is investigated.

Abstract: The spectral and solvatation properties of hydrobromides of 3,3^/,4,4^/,5,5^/-hexamethyldipyrromethene-2,2^/, 3,3^/,4,4^/,5^/-pentamethyldipyrromethene-2,2^/,3,3^/,4^/,5,5^/-pentamethyldipyrromethene-2,2^/, 1^/,3,4,5-tetramethyldipyrromethene-2,2^/, 3,4,5-trimethyldipyrromethene-2,2^/ and their oxa- and thia- analoges in benzene, n-propanol, chloroform, pyridine and N,N-dimethylformamide have been studied. The changes of relative solvation enthalpies are calculated and discussed.

Abstract: 4-(Trihydro-2H-1,2-thiazole-1,1-dioxide-2-yl)benzophenone (1), 4-(3,5-dimethyl-1`,2`-thiazine-1`,1`-dioxide-2-yl)benzophenone (2), and 4-(tetrahydro-2H-1,2-thiazine-1,1-dioxide-2-yl)benzophenone (6) were obtained from 4-aminobenzophenone and the appropriate reagents. Isomeric (E-) and (Z-) 2-Ethoxycarbonyl-4-phenyl-4-(4-tetrahydro-1,2-thiazine-1,1-dioxide-2-yl)phenyl-3-butenoic acids (11 and 12) and 2-carboxy-4(N-phenylthiocarbamoyl)-1-phenyl-6-(tetrahydro-2H-1,2-thiazine-1,1-dioxide-2-yl)naphthalene (16) were also synthesized.

Abstract: 2-Amino-4,5-di-(2-furyl)furan-3-carbonitrile (1) reacted with triethyl orthoacetate to afford the corresponding 2-ethoxyimine derivative (2). The latter compound reacted with phenyl hydrazine, p-fluorobenzylamine and sodium hydrogen sulfide, respectively, to afford the corresponding furo[2,3-d]pyrimidine derivatives (3-5). Compound 1 also reacted with carbon disulfide and phenyl isocyanate to afford 5,6-di-(2-furyl)-1H-4H-furo[2,3-d]-[1,3-thiazin]-4-imino-2-thione (6) and 5,6-di-(2-furyl)-1H-3H-3-phenylfuro[2,3-d]pyrimidin-4-imine-2-one (7), respectively. Treatment of compound 2 with hydrazine hydrate at 0^oC afforded compound 8, while on boiling 5,6-di-(2-furyl)-3H,4H-4-imino-2-methylfuro-[2,3-d]pyrimidin-3-amine (9) was isolated. Treatment of 9 with carbon disulfide, cyanogen bromide, ethyl cyanoacetate, diethyloxalate and triethyl orthoformate gave the corresponding furo[3,2-e][1,2,4]triazolo[1,5-c]pyrimidines (10-14). Reaction of 9 with isatin and N-acetyl isatin gave the condensation products 15 and 16 respectively.

Abstract: Reaction of 2-hydrazino-3-methyl-3,4-dihydrothieno[2,3-d]pyrimidin-4-one derivatives 2a,b with aliphatic acids afforded the thienotriazolopyrimidinone derivatives 3a-d, with nitrous acid yielded tetrazolothienopyrimidinone derivatives 4a,b and with carbon disulphide furnished 3-mercaptothienotriazolopyrimidinone derivatives 5a,b. Also, 2a,b reacted with aldehydes to afford the arylhydrazones 6a-f which cyclized into thienotriazolopyrimidinone derivatives 7a-f. Furthermore, 2a,b condensed with ethyl acetoacetate and ethyl cyanoacetate to afford 2-(1-pyrazolyl) derivatives 9a,b and 10a,b, respectively. On the other hand, 2-hydrazino derivatives 2a,b condensed with a-halo-ketones to yield thienpyrimidotriazinone derivatives 11a,b and with β-diketones, to form 2-(1-pyrazolyl) derivatives 12a-f.

Abstract: In this paper we report examples of the Heck reaction in the new moisture stable ambient temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF₆). We have found that the yield of product is comparable with Heck reactions carried out in DMF, the conventional solvent for this reaction, and that the ionic liquid/catalyst mixture can be recycled several times.

Abstract: Synthesis of trans-1,2-bis(4-nitro-1-p-methoxybenzylimidazol-5-yl)ethene (1) as an imidazole analogue of stilbene has been reported. In order to confirm the trans geometry of the product using an UV spectral comparison, a mixture of both trans (1) and cis isomer (3) was also prepared. The synthesis involved one-step dimerization of the precursor, 4-nitro-1-p-methoxybenzyl-5-methyl-1H-imidazole (2), using N-chlorosuccinimide catalyzed by potassium t-butoxide.

Abstract: Condensation of 4-benzoyl-1,2-phenylenediamine with sodium pyruvate in acetic acid furnished two products which were identified as 6-benzoyl and 7-benzoyl-3-methyl-2(1H)quinoxalinones (1a,b). Fusion of 1a with aromatic aldehydes furnished the styryl derivatives 2a-c. Alkylation of 1a,b with dimethyl sulphate or ethyl chloroacetate produced the N-alkyl derivatives 3a,b and 4a,b. Hydrazinolysis of the ester derivative 4a with hydrazine hydrate afforded the hydrazide derivative 5 which underwent condensation with aldehydes to give the corresponding hydrazone derivatives 6a,b. In addition, chlorination of 1a with thionyl chloride afforded the 2-chloro derivative 7 which was subjected to reaction with sodium azide and n-butylamine to yield the corresponding tetrazolo (8) and n-butylamino (9) derivatives, respectively. The structures of the compounds prepared were confirmed by analytical and spectral data. Also, some of the synthesized compounds were screened for antimicrobial activity.

Abstract: Phenolic enamino compounds, prepared from 2-(4-hydroxyphenyl)-ethylamine and the corresponding β-keto carbonyl compounds, afford spiro cyclohexadienone derivatives on reaction with hypervalent iodine reagents.

Abstract: A tandem demethylation-cyclisation reaction resulting in the formation of pyran rings using AlCl₃/EtSH reagent under mild reaction conditions is reported. X-ray diffraction studies on the intermediate support the suggested mechanism.

Abstract: In this paper we describe the synthesis of tetraphenylphosphonium peroxymonosulphate, its crystal structure and packing mode. The asymmetric unit accomodates two independent molecules of the monopersulphate anion, which are held together by hydrogen bonds. In the packing mode, rows of such dimers are surrounded by four rows of tetraphenyl cations. The consequence is that the highly water sensitive HSO₅¯ anions are segregated inside hydrophobic channels composed by the lipophilic cations. This circumstance presumably accounts for the exceptional stability of the title compound.

Abstract: The 6-aryl-1-(3-chloropropanoyl)-4-[(E)-1-(2-furyl)methylidene)]-1,2,3,4-tetrahydro-3-pyridazinones (6a-d) were synthesized by the reaction of acid chloride 3 with α-aracyl(β-2-furyl)acrylic acid hydrazides (2a-d) in a high yield, one pot reaction. On the other hand, 2-(2-chloroethyl)-5-[α-aracyl-β-(2-furyl)]-(E)-vinyl-1,3,4-oxadiazoles (7a-d) were also prepared by cyclodehydration of N1[α-aracyl-β-(2-furyl)acroyl-N2[3-chloro-propanoyl] hydrazine derivatives (4a-d). The proposed structures of the products were confirmed by elemental analysis, spectral data and chemical evidence.

Abstract: Goyazensolide, a biologically active natural product classified as a furoheliangolide, was transformed in a phthalimide derivative that showed an enhanced biological activity against Tripanosoma cruzi. The complex natural product was also reduced with high stereoselectivity by hydrogen/Wilkinson’s catalyst; an epimer of this product was obtained in the reduction with hydrogen/Pd-C.