A simple efficient sequential one-pot intermolecular aza-Michael addition and intramolecular Buchwald–Hartwig α-arylation of amines: synthesis of functionalized tetrahydroisoquinolines

Recent Developments in the Synthesis of HIV-1 Integrase Strand Transfer Inhibitors Incorporating Pyridine Moiety

Human immunodeficiency virus (HIV) causes one of the most dangerous diseases-acquired immunodeficiency syndrome (AIDS). An estimated about 40 million people are currently living with HIV worldwide, most of whom are already on antiretroviral therapy. This makes the development of effective drugs to combat this virus very relevant. Currently, one of the dynamically developing areas of organic and medicinal chemistry is the synthesis and identification of new compounds capable of inhibiting HIV-1 integrase-one of the HIV enzymes. A significant number of studies on this topic are published annually. Many compounds inhibiting integrase incorporate pyridine core. Therefore, this review is an analysis of the literature on the methods for the synthesis of pyridine-containing HIV-1 integrase inhibitors since 2003 to the present.

Transition-Metal-Free Reductive Hydroxymethylation of Isoquinolines

A transition-metal-free reductive hydroxymethylation reaction has been developed, enabling the preparation of tetrahydroisoquinolines bearing C4-quaternary centers from the corresponding isoquinolines. Deuterium labelling studies and control experiments enable a potential mechanism to be elucidated which features a key Cannizzaro-type reduction followed by an Evans-Tishchenko reaction. When isoquinolines featuring a proton at the 4-position are used, a tandem methylation-hydroxymethylation occurs, leading to the formation of 2 new C-C bonds in one pot.

1,2,3,4-Tetrahydroisoquinolines as inhibitors of HIV-1 integrase and human LEDGF/p75 interaction

Alkaloids are a class of organic compounds with a wide range of biological properties, including anti-HIV activity. The 1,2,3,4-tetrahydroisoquinoline is a ubiquitous structural motif of many alkaloids. Using a short and an efficient route for synthesis, a series of 1,2,3,4-tetrahydroisoquinolines/isoquinolines was developed. These compounds have been analysed for their ability to inhibit an important interaction between HIV-1 integrase enzyme (IN) and human LEDGF/p75 protein (p75) which assists in the viral integration into the active genes. A lead compound 6d is found to inhibit the LEDGF/p75-IN interaction in vitro with an IC₅₀ of ~10 μm. Molecular docking analysis of the isoquinoline 6d reveals its interactions with the LEDGF/p75-binding residues of IN. Based on an order of addition experiment, the binding of 6d or LEDGF/p75 to IN is shown to be mutually exclusive. Also, the activity of 6d in vitro is found to be unaffected by the presence of a non-specific DNA. As reported earlier for the inhibitors of LEDGF/p75-IN interaction, 6d exhibits a potent inhibition of both the early and late stages of HIV-1 replication. Compound 6d differing from the known inhibitors in the chemical moieties and interactions with CCD could potentially be explored further for developing small molecule inhibitors of LEDGF/p75-IN interaction having a higher potency.

Sequential one-pot approach for the synthesis of functionalized phthalans via Heck-reduction–cyclization (HRC) reactions

An efficient and practical method is described for the direct synthesis of 1,3-dihydroisobenzofurans, an important structural motif present in biologically active natural or synthetic compounds.

Lewis acid promoted C–C and copper-catalyzed C–O bond formation: synthesis of neoflavans

An intramolecular [Cu]-catalyzed C–O bond formation for the synthesis of neoflavans is presented.

An efficient synthesis of highly substituted indanones and chalcones promoted by superacid

A superacid promoted one-pot method was developed for the efficient synthesis of indanones. This process enabled the formation of a dual C–C bond between the aryl isopropyl ketones and benzaldehydes. Interestingly, when the reaction was performed between acetophenones and benzaldehydes, it was impeded after the aldol condensation and resulted in the corresponding chalcones.