Unexpected Formation of Bis(hydrazinecarboximidamide) via Ultrasound Promoted Rearrangement of Epoxy Ketone

An efficient synthesis of aromatic pyrazoles via cyclocondensation of epoxy chalcones with hydrazine is reported. When aminoguanidine hydrochloride is the dinucleophilic specie the reaction leads to a mixture of amidino pyrazole and a minor amount (15%) of an interesting co-product identified as 2,2'-(1,3-diphenylpropane-1,2-diylidene)bis(hydrazinecarboximidamide) dihydrochloride by X-ray diffraction and NMR. A plausible mechanism for the co-product formation via rearrangement of the epoxy chalcone into 1,2-diketone followed by the condensation with aminoguanidine reaction is proposed. DOI: http://dx.doi.org/10.17807/orbital.v9i3.97

2-[5-(2-Methylphenyl)-3-(2-methylstyryl)-4,5-dihydro-1H-pyrazol-1-yl]-6-(thiophen-2-yl)-4-(trifluoromethyl)pyrimidine chloroform monosolvate

In the crystal structure of the title compound, C28H23F3N4S·CHCl3, the chloroform solvate molecules connect the pyrimidine molecules into chains along [101] through weak C—H...N and C—H...Cl hydrogen-bond interactions. There are further connections between adjacent chains through F...Cl halogen contacts of 3.185 (3) Å, with the –CF3 group presenting a significant short F...F interchain distance of 2.712 (4) Å. The five-membered pyrazole ring is approximately planar (r.m.s. deviation = 0.050 Å). The pyrimidine ring makes dihedral angles of 84.15 (8) and 4.56 (8)° with the benzene rings

(5E)-1-Benzyl-5-(3,3,3-trichloro-2-oxopropylidene)pyrrolidin-2-one

In the crystal structure of the title compound, C14H12Cl3NO2, no classical hydrogen-bonding interactions are observed. The methylene fragments of the benzyl groups participate in non-classic hydrogen-bond interactions with the carbonyl O atoms of neighboring molecules, generating co-operative centrosymmetric dimers with R55(10) ring motifs. The overall molecular arrangement in the unit cell seems to be highly influenced by secondary non-covalent weak C—Cl...π [Cl...Cg(phenyl ring) = 3.732 (2) Å] and C—O...π [O...Cg(pyrrolidine ring) = 2.985 (2) Å] contacts

(S,Z)-3-Phenyl-2-[(1,1,1-trichloro-7-methoxy-2,7-dioxohept-3-en-4-yl)amino]propanoic acid monohydrate

In the title compound, C17H18Cl3NO5·H2O, intramolecular N—H...O and C—H...Cl hydrogen bonds form S(6) and S(5) ring motifs, respectively. The chiral organic molecule is connected to the solvent water molecule by a short O—H...O hydrogen bond. In the crystal, a weak C—H...Cl interaction connects the organic molecules along [100] while the water molecules act as bridges between the organic molecules in both the [100] and [010] directions, generating layers parallel to the ab plane

2-{1-[(6R,S)-3,5,5,6,8,8-Hexamethyl-5,6,7,8-tetrahydronaphthalen-2-yl]ethylidene}-N-methylhydrazinecarbothioamide

The reaction between a racemic mixture of (R,S)-fixolide and 4-methylthiosemicarbazide in ethanol with a 1:1 stoichiometric ratio and catalysed with HCl, yielded the title compound, C20H31N3S [common name: (R,S)-fixolide 4-methylthiosemicarbazone]. There is one crystallographically independent molecule in the asymmetric unit, which is disordered over the aliphatic ring [site-occupancy ratio = 0.667 (13):0.333 (13)]. The disorder includes the chiral C atom, the neighbouring methylene group and the methyl H atoms of the methyl group bonded to the chiral C atom. The maximum deviations from the mean plane through the disordered aliphatic ring amount to 0.328 (6) and −0.334 (6) Å [r.m.s.d. = 0.2061 Å], and −0.3677 (12) and 0.3380 (12) Å [r.m.s.d. = 0.2198 Å] for the two different sites. Both fragments show a half-chair conformation. Additionally, the N—N—C(=S)—N entity is approximately planar, with the maximum deviation from the mean plane through the selected atoms being 0.0135 (18) Å [r.m.s.d. = 0.0100 Å]. The molecule is not planar due to the dihedral angle between the thiosemicarbazone entity and the aromatic ring, which amounts to 51.8 (1)°, and due to the sp3-hybridized carbon atoms of the fixolide fragment. In the crystal, the molecules are connected by H...S interactions with graph-set motif C(4), forming a mono-periodic hydrogen-bonded ribbon along [100]. The Hirshfeld surface analysis suggests that the major contributions for the crystal cohesion are [(R,S)-isomers considered separately] H...H (75.7%), H...S/S...H (11.6%), H...C/C...H (8.3% and H...N/N...H (4.4% for both of them)

Regiospecific synthesis of new fatty N-acyl trihalomethylated pyrazoline derivatives from fatty acid methyl esters (FAMEs)

Uma série de novas pirazolinas N-acil trialometiladas derivadas de ésteres metílicos de ácidos graxos foi sintetizada por reação de ciclocondensação entre hidrazidas graxas e 4-alcóxi-1,1,1‑trialometil-3-alquen-2-onas. Ciclizações eficientes e regioespecíficas catalisadas por BF3·MeOH levaram aos produtos desejados em rendimentos de bons a excelentes e alto grau de pureza.A series of new fatty N-acyl trihalomethylated pyrazoline derivatives from fatty acid methyl esters was synthesized by the cyclocondensation of respective fatty hydrazides with 4-alkoxy-1,1,1‑trialomethyl-3-alquen-2-ones. Efficient and regiospecific cyclizations catalyzed by BF3·MeOH gave the desired products in good to excellent yields and at high purity