J. Appl. Cryst.の発刊に際して

https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

The biaryl structural motif is a predominant feature in many pharmaceutically relevant and biologically active compounds. As a result, for over a century 1 organic chemists have sought to develop new and more efficient aryl -aryl bond-forming methods. Although there exist a variety of routes for the construction of aryl -aryl bonds, arguably the most common method is through the use of transition-metalmediated reactions. 2-4 While earlier reports focused on the use of stoichiometric quantities of a transition metal to carry out the desired transformation, modern methods of transitionmetal-catalyzed aryl -aryl coupling have focused on the development of high-yielding reactions achieved with excellent selectivity and high functional group tolerance under mild reaction conditions. Typically, these reactions involve either the coupling of an aryl halide or pseudohalide with an organometallic reagent (Scheme 1), or the homocoupling of two aryl halides or two organometallic reagents. Although a number of improvements have developed the former process into an industrially very useful and attractive method for the construction of aryl -aryl bonds, the need still exists for more efficient routes whereby the same outcome is accomplished, but with reduced waste and in fewer steps. In particular, the obligation to use coupling partners that are both activated is wasteful since it necessitates the installation and then subsequent disposal of stoichiometric activating agents. Furthermore, preparation of preactivated aryl substrates often requires several steps, which in itself can be a time-consuming and economically inefficient process.

http://aether.cmi.ua.ac.be/artikels/Artikels%20Gitte/Artikels/Reviews/Heck-Type-lautens.pdf

Aryl-aryl bond formation by transition-metal-catalyzed direct arylation.

Click Chemistry for Drug Development and Diverse Chemical–Biology Applications

Isatins As Privileged Molecules in Design and Synthesis of Spiro-Fused Cyclic Frameworks

Pyranojacareubin; 1,5-dihydroxy-6',6'-dimethyl-2H-pyran(2',3':6,7) -6",6"-dim-ethyI-2H,4H-pyran(2",3":2,3)xanthone and a new xanthone l,6-dihydroxy-5-methoxy-6',6'-dim-ethyl-2H-pyran(2',3':3,2)-7-(3,3-dimethylprop-2-enyl)xanthone were isolated from the ether extract of the root bark of Rheedia acuminata together with friedelin and friedelanol.

/pdf/prenylated-xanthones-from-rheedia-acuminata-dgt8ejq9xj.pdf

PRENYLATED XANTHONES FROM Rheedia acuminata

A mixture of two monoisoprenylated flavonols velloquercetin 3′,4′-dimethyl ether and velloquercetin 3,3′,4′-trimethyl ether have been isolated and characterized from the hexane whole plant extract of Vellozia graminifolia . The structures were determined from spectral data, including 2D-NMR experiments.

Two Monoisoprenylated Flavonoids from Vellozia graminifolia.

A bis-nor-diterpene from Vellozia variabilis

During an investigation of the base-induced transformation of secoisopimarene 1 to gibberellin analog 2, an unexpected solvent-specific cyclization occurred generating a bicyclo[3.2.1]spirodiketone of an unexpected structure class. The structure of this interesting reaction product has been fully defined using comprehensive 2D NMR methods.

Angelo C. Pinto

Papers

PRENYLATED XANTHONES FROM Rheedia acuminata

Two Monoisoprenylated Flavonoids from Vellozia graminifolia.

A bis-nor-diterpene from Vellozia variabilis

An Unexpected Spirodiketone Obtained During Seco-Isopimarene Cyclization

Mercuric Ion Induced Intramolecular Cyclization of 2‐Amino‐4‐alkenylamine Derivatives. Stereoselective Synthesis of 3‐Aminopyrrolidines.