New Substituted Isocoumarins and Dihydroisocoumarins and their Cytotoxic Activities

Abstract

New isocoumarins were prepared in an efficient way from 2-iodobenzoic acid derivatives and hept-1-yne in a Sonogashira reaction, followed by spontaneous cyclization. Catalytic hydrogenation gave the corresponding dihydroisocoumarins. A 4-chloroisocoumarin was prepared on an alternative pathway. Some of the new compounds showed moderate cytotoxic activities against a human leukemia cell line (HL 60).

Boosting Molecular Complexity with O2: Iron‐Catalysed Oxygenation of 1‐Arylisochromans through Dehydrogenation, Csp3−O Bond Cleavage and Hydrogenolysis

“…Unlike 8a and its derivative 8c,t he peroxide species 8p derived from the less electronegative sulfur-based substrate 1p was found to be more stable and could be subjected to purification by silica gelc hromatography withouts howing significant decomposition. As indicated by previous 18 O 2 labelling experiments, [21a] the formation of the peroxide intermediate does not involvet he cleavage of the OÀOb ond in the O 2 molecule, thus discarding the formation of iron-oxo species.…”

“…[17] Of particularn ote is the oxidative cleavage of the endocyclic Csp 3 ÀOb ond in 1-arylisochromans, which has been exploited by medicinal chemists fort he synthesis of benzodiazepines, benzodiazepinones and benzodiazepinethiones, analogues of the neuroprotective agent GYKI52466 and the related LY300164 and tofisopam (Scheme 1A). [18] Given the therapeutic potentialo fs uch compounds in treating epilepsy,s pasticity,c hronic pain and neurodegenerative disorders, it would be highly desirable to develop catalysts capable of aerobico xidative cleavage of the Csp 3 ÀO bond in 1-arylisochromans. To the best of our knowledge,l accase enzymesa ppear to be the only catalysts that have been reportedt op romote such reactions (Scheme 1B).…”

7-Aza-des-A-steroids with Antimicrobial and Cytotoxic Activity

“…The assay was performed as described in detail previously [21] using the microorganisms listed in Table 1. Paper discs (6 mm diameter) were impregnated with 30 μg of each test substance or the reference drugs.…”

“…The assay originally worked out by Mosmann [17] was performed as described in detail previously [21] using HL-60 cells. The experiments were performed in triplicate.…”

Synthesis of 4-Chloroisocoumarins via Intramolecular Halolactonization of o-Alkynylbenzoates: PhICl2-Mediated C–O/C–Cl Bond Formation

“…45 However, these methods are applicable only to the preparation of 4-iodo/bromoisocoumarins, and the synthesis of 4-chloroisocoumarins relies predominantly on the application of transition metal-mediated approaches. 33,35,[38][39][40]44 For example, Lisowski described a Cy 2 NH•HCl-promoted cyclization of o-alkynylbenzoates with CuCl 2 to give 4-chloroisocoumarins (Scheme 1, method a). 35 Similarly, Miyata reported the halocyclization of o-alkynylbenzoates using CuCl 2 /NCS (Scheme 1, method b).…”