Microwave-assisted efficient one-step synthesis of amides from ketones and benzoxazoles from (2-hydroxyaryl) ketones with acetohydroxamic acid using sulfuric acid as the catalyst

Efficient one-step method for the synthesis of amides directly from ketones and benzoxazoles from (2-hydroxyaryl) ketones by the reaction of acetohydroxamic acid using sulfuric acid as catalyst was described.     

The Zolmitriptan-Pyridine (1:1) and Zolmitriptan-Propiophenone (3:2) Inclusion Complex

Abstract  

The crystal structures of zolmitriptan with pyridine (I) and propiophenone (II) solvates have been determined by single crystal X-ray diffraction studies. Compound (I) crystallizes in the orthorhombic space group P2₁2₁2₁ with a = 8.5610(5) ?, b = 12.2709(7) ?, c = 19.6201(12) ?, V = 2061.1(2) ?³, and Z = 4, while compound (II) crystallizes in the monoclinic space group P2₁ with a = 15.085(1) ?, b = 19.656(12) ?, c = 21.0860(13) ?, β = 92.068(1)°, V = 6248(4) ?³ and Z = 4. The asymmetric unit of (I), C₁₆H₂₁N₃O₂·C₅H₅N, contains one zolmitriptan molecule and one pyridine solvate, while the asymmetric unit of (II), 3(C₁₆H₂₁N₃O₂)·2(C₉H₁₀O) comprises six zolmitriptan molecules and four propiophenone solvates. In both structures, the N–H···N hydrogen bonds, form an infinite helical chain and generate a C(11)-type motif in (I) and a D₂²(13)-type motif in (II). Both the complexes have layer structures, the layers being constructed from rings (cavity) of four zolmitriptan molecules, hydrogen bonded through N–H···N and N–H···O bonds, where the pyridine (I) and propiophenone (II) solvates are included in an R₄⁴(33) ring.     

Design and synthesis of oxaprozin-1,3,4-oxadiazole hybrids as potential anticancer and antibacterial agents

In the present study, we report design, synthesis and screening of new novel 5-substituted-2-mercapto-1,3,4-oxadiazole analogues appended to oxaprozin for their in vitro anticancer and antibacterial activity. The synthesised compounds were characterized using various spectroscopic techniques. Furthermore, the structure of 5b (2-(2-[4,5-diphenyloxazol-2-yl]ethyl)-5-(ethylthio)-1,3,4-oxadiazole) was unequivocally confirmed by X-ray analysis. Among the series 5c (2-(2-[4,5-diphenyloxazol-2-yl]ethyl)-5-(propylthio)-1,3,4-oxadiazole) showed most promising anticancer activity against A549 cancer cell line and all the reported analogues manifested satisfactory safety profiles against human normal cell line HEK293T. The products exhibited good antibacterial activity and among the tested 5j (2-(2-[4,5-diphenyloxazol-2-yl]ethyl)-5-([4-fluorobenzyl]thio)-1,3,4-oxadiazole) exhibited most potent.     

Synthesis, characterization, crystal and molecular structure analysis of N-(2,4-dimethylphenyl)-6-methyl-4-(3-nitrophenyl)-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide

A novel dihydropyrimidine (DHPM) derivative bearing a carbamoyl moiety was synthesized by an efficient three-component Biginelli reaction and was characterized spectroscopically and finally confirmed by X-ray diffraction studies. The title compound C₂₀H₂₀N₄O₄ crystallizes in the monoclinic space group P2₁/c with cell parameters a=12.8970(12) Å, b=13.6210(11) Å, c=11.8420(13) Å, β=115.860(3)°, Z=4 and V=1872.0(3) Å³. The conformation of the dihydropyrimidine ring is unusual; it is planar instead of the usual boat-like conformation. The 3-nitrophenyl ring is orthogonal to the 3,4-DHPM ring. The carbonyl group is in an anti-clinal conformation.     

Chains of edge‐fused hydrogen‐bonded R33(22) rings in 5,3′‐dihydr­oxy‐3,6,7,4′,5′‐penta­methoxy­flavone

The title compound [systematic name: 5‐hydroxy‐2‐(3‐hydroxy‐4,5‐dimethoxy­phenyl)‐3,6,7‐trimethoxy‐4H‐chromen‐4‐one], C₂₀H₂₀O₉, was isolated from the seeds of Cleom viscosa Linn. Two independent mol­ecules (A and B) are present in the asymmetric unit with almost similar conformations. The dihedral angles between the fused chromene ring system and the benzene ring bonded to it in mol­ecules A and B are 4.2 (1) and 12.7 (1)°, respectively. The hydroxy O atoms are involved in intra­molecular hydrogen bonding. The mol­ecules are linked by C—H⋯O and O—H⋯O inter­actions into chains of edge‐fused R₃³(22) rings. Aromatic π–π and weak C—H⋯π(arene) inter­actions are also observed.     

Crystal Forms of the Antiepileptic Lamotrigine: Molecular Salts and Solvates with Fluorobenzoic Acid,Nicotinic Acid, 2-Thiobarbituric Acid, 3-Picoline and Butyl Alcohol

Abstract  

The crystal structures of three salts and two solvated multicomponent crystals of lamotrigine with 4-fluorobenzoic acid, nicotinic acid, 2-thiobarbituric acid, 3-picoline and butyl alcohol are reported. Compound 1a crystallizes in monoclinc system, space group P2₁ with a = 13.3860(5) ?, b = 8.3420(3) ?, c = 15.5200(6) ?, β = 93.524(1)°, V = 1729.78(11) ?³, and Z = 2. Compound 1b crystallizes in monoclinic system, space group P2₁/c with a = 10.6625(7) ?, b = 16.2575(11) ?, c = 13.6346(9) ?, β = 100.904(1)°, V = 2320.8(3) ?³, and Z = 4. Compound 1c crystallizes in triclinic system, space group P[`1] \overline{1} , with a = 10.1309(7) ?, b = 12.0260(8) ?, c = 14.0826(10) ?, α = 71.783(1)°, β = 86.451(1)°, γ = 80.902(1)°, V = 1609.10(19) ?<sup>3</sup>, and Z = 1. Compound 1d crystallizes in monoclinic system, space group P2<sub>1</sub>/c with a = 14.9570(10) ?, b = 8.0230(6) ?, c = 13.8162(10) ?, β = 102.884(1)°, V = 1616.2(2) ?<sup>3</sup>, and Z = 4. Compound 1e crystallizes in triclinic system, space group P[`1] \overline{1} , with a = 7.5710(6) ?, b = 8.5721(7) ?, c = 13.5532(11) ?, α = 85.364(1)°, β = 79.632(1) (1)°, γ = 86.188(1)°, V = 861.19(12) ?³, and Z = 2. Characteristic R₂²(8) dimer is observed in all five structures. A complete hydrogen bonded motif analysis is described. Lamotrigine-lamotrigine base pair is observed in all the structures, except in (1b). In (1c), the R₂²(7) dimer is noticed while, in all other structures R₂²(8) dimer exist between the lamotrigine-lamotrigine base pair. In all the six structures, chlorine atoms of the lamotrigine molecules are not involved in any interactions.     

Numerical simulation of vortex induced vibrations and its control by suction and blowing

The vortex formation and shedding behind bluff structures is influenced by fluid flow parameters such as, Reynolds number, surface roughness, turbulence level, etc. and structural parameters such as, mass ratio, frequency ratio, damping ratio, etc. When a structure is flexibly mounted, the Kármán vortex street formed behind the structure gives rise to vortex induced oscillations. The control of these flow induced vibrations is of paramount practical importance for a wide range of designs. An analysis of flow patterns behind these structures would enable better understanding of wake properties and their control. In the present study, flow past a smooth circular cylinder is numerically simulated by coupling the mass, momentum conservation equations along with a dynamical evolution equation for the structure. An active flow control strategy based on zero net mass injection is designed and implemented to assess its efficacy. A three actuator system in the form of suction and blowing slots are positioned on the cylinder surface. A single blowing slot is located on the leeward side of the cylinder, while two suction slots are positioned at an angle α = 100°. This system is found to effectively annihilate the vortex induced oscillations, when the quantum of actuations is about three times the free stream velocity. The dynamic adaptability of the proposed control strategy and its ability to suppress vortex induced oscillations is verified. The exact quantum of actuation involved in wake control is achieved by integrating a control equation to decide the actuator response in the form of a closed loop feed back system. Simulations are extended to high Reynolds number flows by employing eddy viscosity based turbulence models. The three actuator system is found to effectively suppress vortex induced oscillations.