Reactions of 3-(p-substituted-phenyl)-5-chloromethyl-1,2,4-oxadiazoles with KCN leading to acetonitriles and alkanes via a non-reductive decyanation pathway.

The present work describes an unfamiliar reaction of 5-(chloromethyl)-3-substituted-phenyl-1,2,4-oxadiazoles with KCN affording trisubstituted 1,2,4-oxadiazol-5-ylacetonitriles and their parent alkanes, namely, 1,2,3-trisubstituted-1,2,4-oxadiazol-5-ylpropanes. To the best of our knowledge, the current synthetic route leading to decyanated products will be the first in terms of a decyanation process which allows the transformation of trisubstituted acetonitriles into alkanes by the incorporation of KCN with the association of in situ-formed HCN and most likely through the extrusion of cyanogen which could not be detected or isolated. In addition, the plausible mechanisms were proposed for both transformations. The structures of the title compounds were identified by means of IR, 1H NMR, 13C NMR, 2D NMR spectra, TOF-MS and X-ray measurements.

Novel benzothiophene 1,1-dioxide deoxygenation path for the microwave-assisted synthesis of substituted benzothiophene-fused pyrrole derivatives.

The reaction of C-(4-substituted-phenyl)-N-(benzoyl)-N-methylglycines with benzo[b]thiophene 1,1-dioxide unexpectedly gave benzothiophene-fused pyrrole derivatives in toluene under microwave irradiation via a cycloaddition and metal-free Pummerer-type sulfone deoxygenation path. In order to obtain the desired sulfone derivatives, the sulfide group underwent oxidation with m-CPBA to afford sulfones. The structures of all the new products were elucidated by spectroscopic/physical methods and, in two cases, by X-ray diffraction.

Synthesis and crystal structure of new heterocyles derived from saccharin and uracil carrying 1,2,4-oxadiazolylmethyl group.

Saccharin, uracil, and 1,2,4-oxadiazole heterocyles are important in terms of exhibiting various biological acitivities. In this work, four series of 1,2,4-oxadiazolylmethyl-substituted saccharin, and uracil derivatives are synthesized and their structures are identified by means of spectral/physical characteristics. The first series are oxadiazolylmethyl-substituted saccharins. The second one is oxadiazole-substituted uracils which are obtained as a separable mixture of both mono- and bis-substituted end products. Third series is obtained from 5-amino uracil and chloromethyl oxadiazoles. The fourth group is oxadiazolyl methyl-substituted imino uracils. The structures of some title compounds are also confirmed by X-ray diffraction data.

Microwave-assisted coupling reaction of N-aryl sydnones with 2-nitromethylenethiazolidine: unexpected formation of (Z)-2-(nitro((E)-p-substitutedphenyldiazenyl)methylene)thiazolidines.

Reaction of N-aryl sydnones with 2-nitromethylenethiazolidine straightforwardly gives rise to the formation of (Z)-2-(nitro((E)-p-substitutedphenyldiazenyl)methylene)thiazolidines in xylene and dimethoxyethane under microwave irradiation. A meaningful and plausible mechanism for this transformation is proposed, which anticipates the extrusion of an aceto-lactone-like moiety before a coupling occurs. The structures of all the new compounds were identified on the basis of the data obtained from the NMR, IR, X-ray diffraction spectra, HRMS measurements, and physical characteristics.

Synthesis and crystal structure of new heterocycles containing 1,2,4-oxadiazole, 1,2,4-oxadiazolone (thione), hydantoin, and mercaptobenzimidazole units.

A number of 1,2,4-oxadiazolone and mercapto nitro benzimidazole derivatives containing 1,2,4-oxadiazole and hydantoin moieties have been prepared, and their structures were identified by means of spectral/physical characteristics including X-ray diffraction data.

Synthesis and anti-protozoal activity of novel dihydropyrrolo[3,4-d][1,2,3]triazoles.

1,2,4-Oxadiazole and 1,2,3-triazole containing heterocyclic compounds continue to gain interest in synthesis of chemical entities and exhibit various biological activities as anti-protozoal and anti-cancer agents. By using the principle of bioisosterism, a series of novel oxadiazolyl pyrrolo triazole diones; namely, (3aS,6aR)-1-((3-(4-substituted phenyl)-1,2,4-oxadiazol-5-yl)methyl)-5-phenyl-1,6a-dihydropyrrolo[3,4-d][1,2,3] triazole-4,6(3aH,5H)-diones (5a-k) was designed and synthesized by the 1,3-dipolar cycloaddition reaction of novel 5-azidomethyl 3-aryl substituted 1,2,4-oxadiazoles (4a-k) with N-phenyl maleimide. The structures of all the cycloadducts were elucidated by means of spectroscopic methods and physical characteristics. The in vitro anti-protozoal and cytotoxic activities of these novel heterocyclic compounds were investigated.

Regioselective 1,3-dipolar cycloaddition of phenanthrolinium N-ylides to substituted arylidene oxazolones.

The 1,3-dipolar cycloaddition reactions of phenanthrolinium ylides have been investigated. Thus 15 novel aryl substituted spiro[oxazole-4,10'-pyrrolo[1,2-a][1,10] phenanthrolin]-5-ones were prepared in a regioselective manner, by the treatment of phenanthrolinium ylides with (Z)-arylidene oxazolones.

(Phen-yl)(3-phenyl-sulfonyl-1,2-dihydro-pyrrolo-[1,2-a]quinoxalin-1-yl)methanone.

In the title mol-ecule, C(24)H(18)N(2)O(3)S, the 13-atom ring system comprising the quinoxaline and fused five-membered ring exhibits an r.m.s. deviation from coplanarity of 0.039 Å, with a maximum deviation of 0.0710 (10) Šfor the PhCO-bearing C atom of the five-membered ring. The 10-membered C(8)N(2) quinoxaline ring system has an r.m.s. deviation from coplanarity of 0.022 Å, with a maximum deviation of 0.0403 (9) Šfor the C atom involved in the C=C bond in the five-membered ring. The three atoms of the five-membered ring fused to the quinoxaline ring system show deviations of up to 0.118 (2) Šfor the PhCO-bearing C atom. C-N bond distances in the quinoxaline ring system of the title mol-ecule deviate from those in unsubstituted quinoxaline. In particular, the two C-N distances to the N atom involved in the five-membered ring are essentially equal, with values of 1.3786 (17) and 1.3773 (16) Å, unlike the difference of nearly 0.06 Šin quinoxaline.

Reaction of heterocyclic enamines with nitrile oxide and nitrilimine precursors.

Alkylidenepyrrolidines 1, 21, 24 and 26 undergo reactions with nitrile oxides and nitrilimines or their precursors to give a range of novel heterocyclic compounds. With alkylidenepyrrolidine ester 1, nitrolic acids give products in which the liberated nitrous acid reacts with the alkylidenepyrrolidine, followed by two cycloadditions to give adducts 3. In contrast, hydroximoyl chlorides give isoxazoles 10, presumably by cycloaddition/elimination. With hydrazonyl chlorides, simple acylation of the alkylidenepyrrolidine occurs to give compounds 17. With sulfonyl alkylidenepyrrolidines 24 and 26, cycloaddition onto the imine tautomer is the preferred pathway, with a stereoselective reaction taking place in the latter case.

A cycloaddition product of a chiral maleimide: 4-{(3aS*,6aS*)-4,6-dioxo-1-phenyl-5-[(1R)-1-phenyl-ethyl]-1,3a,4,5,6,6a-hexa-hydro-pyrrolo[3,4-c]pyrazol-3-yl}phenyl acetate.

In the title mol-ecule, C(27)H(23)N(3)O(4), the two central five-membered rings form a dihedral angle of 63.66 (4)°. The absolute configuration was determined by analysis of Bijvoet pairs based on resonant scattering of light atoms, yielding a Hooft parameter y = -0.10 (7).

(3aR,6aR)-1-Phenyl-5-[(R)-1-phenyl-ethyl]-3-[4-(trifluoro-meth-yl)phen-yl]-1,6a-dihydro-pyrrolo[3,4-c]pyrazole-4,6(3aH,5H)-dione.

In the title mol-ecule, C(26)H(20)F(3)N(3)O(2), the two central five-membered rings form a dihedral angle of 62.94 (8)°. The absolute configuration was determined by analysis of Bijvoet pairs based on resonant scattering of light atoms, yielding a Hooft parameter y = -0.05 (11). Notable intra- and inter-molecular contacts include C-H⋯O and C-H⋯π(arene) hydrogen bonds.

Bis(3-phenyl-1,2,4-thiadiazole-5-thiolato)mercury(II).

The title compound, [Hg(C8H5N2S2)2], has crystallographic C2 symmetry. The Hg-S distance is 2.353 (2) A and the coordination geometry is linear, with an S-Hg-S angle of 179.77 (18) degrees. The exocyclic C-S single-bond distance is 1.749 (6) A, and intramolecular Hg...N distances of 2.857 (4) A exist, as well as secondary Hg...C and S...S contacts.