A facile and highly diastereoselective synthesis of carbocyclic spiro-pyrazolones via DABCO catalyzed Michael-Michael domino reaction

An efficient domino Michael-Michael reaction of ω- and δ-nitro α,β-unsaturated esters with alkylidenepyrazolones has been accomplished using DABCO as the organocatalyst under mild reaction conditions. Under the present organocatalytic method, a wide range of carbocyclic spiro-pyrazolones with three tertiary stereogenic centers and a quaternary stereocenter has been prepared in high yields and excellent diastereoselectivities. An ester and nitro groups present in the spiro-pyrazolones have been utilized for further structural transformations.     

Synthesis of succinimidyl-(S)-naproxen ester and its application for indirect enantioresolution of penicillamine by reversed-phase high-performance liquid chromatography

Synthesis of N-succinimidyl-(S)-2-(6-methoxynaphth-2-yl) propionate was carried out by the reaction of (S)-naproxen with N-hydroxysuccinimide in the presence of dicyclohexyl carbodiimide. It was characterized and was used as a chiral derivatizing reagent, under mild conditions, to form diastereomers of dl-penicillamine which were resolved by reversed-phase high-performance liquid chromatography using triethyl ammonium phosphate buffer (pH 4.0, 5mM)-acetonitrile (linear gradient (30min) of acetonitrile from 30 to 70%). Excellent separation was achieved with gradient mobile phase. The detection limit was at pmol level.     

Visible Light Mediated Halogen Atom Transfer to Access Polyhalogenated and Deuterated Lactams from Alkyl Halides

A visible light mediated protocol for the synthesis of polyhalogenated and deuterated δ- and γ-lactams from readily available alkyl halides is reported. The reaction involves the generation of haloalkyl radicals through halogen atom transfer (XAT) and subsequent arylalkylation of olefins to afford dihydroisoquinolinones and oxindoles. This new XAT protocol exhibits wide scope under mild conditions and enables access to new halogenated chemical space.     

Gold(I)-Catalyzed and PTSA-Promoted Cycloisomerization of Ynamides to Access Pyrrole Substituted α,β-Unsaturated Ketones**

Substituted pyrroles are prevalent aromatic ring systems encountered in numerous natural products and bioactive molecules. Herein, a novel ynamide scaffold has been designed, synthesized and subsequently applied to an unprecedented gold-catalyzed and para-toluenesulfonic acid (PTSA)-assisted cascade cycloisomerization reaction for the synthesis of β-pyrrole substituted α,β-unsaturated ketones. Notably, the reaction is stereoselective, offering E-isomer as major product with low to moderate yield.     

Engineering Biomimetic Microenvironment for Organoid

Organoid is an emerging frontier technology in the field of life science, in which pluripotent stem cells or tissue-derived differentiated/progenitor cells form 3D structures according to their multi-directional differentiation potential and self-assembly ability. Nowadays, although various types of organoids are widely investigated, their construction is still complicated in operation, uncertain in yield, and poor in reproducibility for the structure and function of native organs. Constructing a biomimetic microenvironment for stem cell proliferation and differentiation in vitro is recognized as a key to driving this field. This review reviews the recent development of engineered biomimetic microenvironments for organoids. First, the composition of the matrix for organoid culture is summarized. Then, strategies for engineering the microenvironment from biophysical, biochemical, and cellular perspectives are discussed in detail. Subsequently, the newly developed monitoring technologies are also reviewed. Finally, a brief conclusion and outlook are presented for the inspiration of future research.     

The Neumann Problem for the Kohn-Laplacian on the Heisenberg Group ℍn$\mathbb H_{n}$

The existence and uniqueness of the solution of the Neumann problem for the Kohn-Laplacian relative to the Korányi ball on the Heisenberg group \(\mathbb {H}_{n}\) are discussed. Explicit representation for a Green’s type function (Neumann function) for the Korányi ball in \(\mathbb {H}_{n}\) for circular functions has been obtained. This function is then used on the above region in \(\mathbb {H}_{n}\) to solve the inhomogeneous Neumann boundary value problem for certain circular data.     

Small silicon memories: confinement, single-electron,. and interface state considerations

Memories that utilize single-electron effects are an attempt at combining the discreteness observable in transport of electrons on to very small capacitances (∼10^-18 F) and into three-dimensionally quantum-confined states, with the reproducibility, architecture and integration of the field-effect devices. We discuss the role size plays in the operation and its variability for such memories. In particular, we discuss the implications of size effects through barriers on speed; through electrostatics on variability, acceptability and reproducibility of properties desired; through random variations and of tunneling on limits in the use of the field-effect, and through interface-states on the time-domain operation. For device properties and their variations, using silicon-on-insulator substrates, silicon and back-insulator thicknesses matter through the linear variations introduced in the electrostatic potential and quadratic variations introduced in the subband energies, the quantum-dots and nano-crystals matter secondarily through the electrostatics and the linear dependence of capacitance on size and the quadratic dependence of the allowed eigen-energies on size. We also discuss the implications of tunneling on time constants of charging of the confined states and in between the source and the drain for the ultimate structure size limit. Received: 14 April 2000 / Accepted: 17 April 2000 / Published online: 6 September 2000     

Phytochemistry,Food Application,and Therapeutic Potential of the Medicinal Plant (Withania coagulans): A Review

Herbal plants have been utilized to treat and cure various health-related problems since ancient times. The use of Ayurvedic medicine is very significant because of its least reported side effects and host of advantages. Withania coagulans (Family; Solanaceae), a valuable medicinal plant, has been used to cure abnormal cell growth, wasting disorders, neural as well as physical problems, diabetes mellitus, insomnia, acute and chronic hepatic ailments. This review provides critical insight regarding the phytochemistry, biological activities, and pharmacognostic properties of W. coagulans. It has been known to possess diuretic, anti-inflammatory, anti-bacterial, anti-fungal, cardio-protective, hepato-protective, hypoglycemic, anti-oxidative, and anti-mutagenic properties owing to the existence of withanolides, an active compound present in it. Apart from withanolides, W. coagulans also contains many phytochemicals such as flavonoids, tannins, and β-sterols. Several studies indicate that various parts of W. coagulans and their active constituents have numerous pharmacological and therapeutic properties and thus can be considered as a new drug therapy against multiple diseases.     

An Intricate Review on Nutritional and Analytical Profiling of Coconut,Flaxseed, Olive,and Sunflower Oil Blends

Vegetable oils (VOs), being our major dietary fat source, play a vital role in nourishment. Different VOs have highly contrasting fatty acid (FA) profiles and hence possess varying levels of health protectiveness. Consumption of a single VO cannot meet the recommended allowances of various FA either from saturated FA (SFA), monounsaturated FA (MUFA), polyunsaturated FA (PUFA), Ω-3 PUFAs, and medium-chain triglycerides (MCTs). Coconut oil (CO), flaxseed oil (FO), olive oil (OO), and sunflower oil (SFO) are among the top listed contrast VOs that are highly appreciated based on their rich contents of SFAs, Ω-3 PUFAs, MUFAs, and Ω-6 PUFA, respectively. Besides being protective against various disease biomarkers, these contrasting VOs are still inappropriate when consumed alone in 100% of daily fat recommendations. This review compiles the available data on blending of such contrasting VOs into single tailored blended oil (BO) with suitable FA composition to meet the recommended levels of SFA, MUFA, PUFA, MCTs, and Ω-3 to Ω-6 PUFA ratios which could ultimately serve as a cost-effective dietary intervention towards the health protectiveness and improvement of the whole population in general. The blending of any two or more VOs from CO, FO, OO, and SFO in the form of binary, ternary, or another type of blending was found to be very conclusive towards balancing FA composition; enhancing physiochemical and stability properties; and promising the therapeutic protectiveness of the resultant BOs.