Two-step, high-yielding total synthesis of antibiotic pyrones.

A simple two-step dialkylation protocol was developed to synthesize biologically active antibiotics photopyrones, pseudopyronines, and violapyrones from bio-renewable triacetate lactone in excellent yields. These pyrones are functionally modified into another set of pyrone natural products by a single -methylation reaction. The high-yielding gram scale synthesis of four natural products [pseudopyronine A, photopyrone A, pseudopyronine B and photopyrone C] demonstrated the viability for industrial applications.

Organocatalytic Reductive Amination of the Chiral Formylcyclopropanes: Scope and Applications.

We developed a sustainable three-component reductive amination protocol for the chemoselective coupling of optically active functionally rich donor-acceptor carbonyl-cyclopropanes with various amines under 10 mol % of diphenyl phosphate in the presence of Hantzsch ester as a hydride source. The catalytic selective reductive C-N coupling has wide advantages like no epimerization, no ring opening, large substrate scope, generating only mono -alkylation products and simultaneously resulting in chiral cyclopropane-containing amines possessing many applications in the medicinal chemistry. In this article, we have shown the synthetic applications of reductive C-N coupling reaction to make chiral α-carbonyl-cyclopropane containing amines , double C-N coupled cyclopropane-amines , unusual C-N/C-C coupled cyclopropane-amines , chiral -butylsulfinamide containing cyclopropanes , and functionally rich chiral cyclopropane-fused -heterocycles .

Direct Organocatalytic Chemoselective Reductive Alkylation of Chiral 2-Aroylcyclopropanecarbaldehydes: Scope and Applications.

We developed a simple and practically feasible protocol for the chemoselective coupling of optically active functionally rich 2-aroylcyclopropanecarbaldehydes with various CH acids or active methylene compounds under 10 mol % of ()-proline in the presence of Hantzsch ester as a hydrogen source through a three-component reductive alkylation reaction. The metal-free, organocatalytic selective reductive C-C coupling method has wide advantages/applications like no epimerization, no ring opening, high carbonyl control, and large substrate scope, generating only monoalkylated 2-aroylcyclopropanes, and the resulting chiral products can be synthons in medicinal to material chemistry. We have also shown the synthetic applications of chiral CH-acid-containing 2-aroylcyclopropanes by transforming them into the interesting molecules of pyrimidine analogues , dimethyl cyclopropane-malonates , functionally rich dihydropyran , cyclopropane-alcohols , and cyclopropane-olefins .

Strategies for Expanding Donors Pool in Heart Transplantation.

Heart transplant remains the criterion standard treatment for patients in end-stage heart failure. Improvement in the post-heart transplant outcomes in the last decade has contributed to increased demand for organs. Worldwide each year, more than 5000 heart transplants are performed and 50,000 people become candidates for heart transplant.

Modular Access to Chiral 2,3-Dihydrofurans and 3,4-Dihydro-2 H-pyrans by Stereospecific Activation of Formylcyclopropanes through Combination of Organocatalytic Reductive Coupling and Lewis-Acid-Catalyzed Annulative Ring-Opening Reactions.

An organocatalytic reductive coupling and Lewis-acid-catalyzed annulative ring-opening strategy is developed as a two-step protocol for the stereoselective synthesis of dihydropyrans as the major products from the chiral formylcyclopropanes, CH acids, and Hantzsch ester. It is an efficient, catalytic, two-step protocol for the chiral synthesis of dihydropyrans and dihydrofurans. Structurally important and challenging functionally rich cyclopropanes containing cyclic-1,3-diones were synthesized in very good yields with excellent chemo-, enantio-, and diastereoselectivities from the readily available starting materials, chiral formylcyclopropanes, cyclic-1,3-diones, or CH acids and Hantzsch ester through an organocatalytic reductive coupling reaction at ambient conditions, especially without harming the cyclopropane ring.

Main vegetation types and plant species diversity along an altitudinal gradient of Al Baha region, Saudi Arabia.

Plant species composition patterns and vegetation types were investigated along Elevational Gradients in Al Baha region, Saudi Arabia. Sandy plain, wadis, drainage lines, rocky outcrops, hills and fallow lands occur over a wide geographic range encompassing variation in plant species and communities among these different ecological sites. To provide a quantitatively based classification of the vegetation we used Multi Variant Statistical Package (MVSP) software, followed by the re-arrangement of a matrix of the similar plant species in rows and similar sample sites in columns.

Luteal versus follicular phase surgical oophorectomy plus tamoxifen in premenopausal women with metastatic hormone receptor-positive breast cancer.

Purpose: In premenopausal women with metastatic hormone receptor-positive breast cancer, hormonal therapy is the first-line therapy. Gonadotropin-releasing hormone analogue + tamoxifen therapies have been found to be more effective. The pattern of recurrence risk over time after primary surgery suggests that peri-operative factors impact recurrence.

Safety and immunogenicity profile of human papillomavirus-16/18 AS04 adjuvant cervical cancer vaccine: a randomized controlled trial in healthy adolescent girls of Bangladesh.

Aim: Bangladesh has the highest level of incidence and mortality rates due to cervical cancer among women. The prevalence of cervical cancer in Bangladeshi women is 25-30/100,000. Human papillomavirus is an important cause of cervical cancer.