A solvent-free and catalyst-free reaction of -aminobenzophenone with aryl isothiocyanates: expedient access to congested 4-phenyl-4-hydroxyquinazolin-2-thione derivatives.

An efficient method to construct 4-phenyl-4-hydroxyquinazolin-2-thiones 3 solvent-free and catalyst-free addition of -aminobenzophenone 1 with aryl isothiocyanates 2 under thermal conditions has been developed, providing new congested 4-phenyl-4-hydroxyquinazolin-2-thiones 3 in practically quantitative yields simple purification by filtration/recrystallization. Extension of these conditions to -aminoacetophenone 4 in place of -aminobenzophenone 1 led to 4-methylenequinazoline-thione 5 as a result of a subsequent dehydration reaction.

Base- and sulfur-promoted oxidative lactonization of chalcone-acetate Michael adducts: access to pyran-2-ones.

A cost-effective, practical, straightforward and scalable synthesis of α-pyrones base- and sulfur-promoted annulation of phenylacetates and chalcones is reported. Generated from the starting components by using dbu as a base catalyst, the Michael adducts underwent a smooth oxidative cyclization into 3,4,6-triaryl-2-pyranones upon heating with DABCO and sulfur in DMSO. Extension to malonate in place of phenylacetates led to 4,6-diaryl-2-pyranone-2-carboxylates.

Sodium sulfide-promoted regiodefined redox condensation of -nitroanilines with aryl ketones to benzo[]phenazines and quinoxalines.

Inexpensive sodium sulfide trihydrate was found to promote unprecedented 6e-regio-predefined redox condensation of -nitroanilines with α-tetralones to benzo[]phenazines. The method was also successfully extended to acetophenones and higher homologs as reducing partners to provide 2-phenylquinoxalines. Compared to traditional approaches toward benzo[]phenazine and quinoxaline cores starting with -phenylenediamines, the present strategy could afford these heterocycles with well-defined regiochemistry based on the structure of starting -nitroanilines.

Seasonal Developing Xylem Transcriptome Analysis of Unveils Novel Insights for Compression Wood Formation.

Wood is the most important renewable resource not only for numerous practical utilizations but also for mitigating the global climate crisis by sequestering atmospheric carbon dioxide. The compressed wood (CW) of gymnosperms, such as conifers, plays a pivotal role in determining the structure of the tree through the reorientation of stems displaced by environmental forces and is characterized by a high content of lignin. Despite extensive studies on many genes involved in wood formation, the molecular mechanisms underlying seasonal and, particularly, CW formation remain unclear.

DABCO-Catalyzed DMSO-Promoted Sulfurative 1,2-Diamination of Phenylacetylenes with Elemental Sulfur and -Phenylenediamines: Access to Quinoxaline-2-thiones.

The oxidative amination of alkynes typically requires transition metal catalysts and strong oxidants. Herein, we alternatively utilize DABCO as a sulfur-activating catalyst to achieve the sulfurative 1,2-diamination of phenylacetylenes with elemental sulfur and -phenylenediamines. DMSO was found to be particularly suitable for use as a terminal oxidant for this three-component process.

Fe/S-Catalyzed Redox Condensation of -Nitrophenols with Isothiocyanates to 2-Aminobenzoxazoles.

As frequently encountered byproducts of isocyanate chemistry, hydrogen sulfide and related sulfur containing compounds should be treated in a safe way to lower their adverse health and environmental effects, especially in large scale syntheses. As a proof of concept, we report herein an example of in situ recycling of sulfur byproduct to reductant in the synthesis of bioactive 2-aminobenzoxazoles . Using an Fe/S catalytic system, this heterocyclic scaffold could be obtained from nitrophenols with isothiocyates via direct redox condensation consisting of reduction of the nitro group of by the sulfur moiety of .

Exploring the Seasonal Dynamics and Molecular Mechanism of Wood Formation in Gymnosperm Trees.

Forests, comprising 31% of the Earth's surface, play pivotal roles in regulating the carbon, water, and energy cycles. Despite being far less diverse than angiosperms, gymnosperms account for over 50% of the global woody biomass production. To sustain growth and development, gymnosperms have evolved the capacity to sense and respond to cyclical environmental signals, such as changes in photoperiod and seasonal temperature, which initiate growth (spring and summer) and dormancy (fall and winter).

Comparative functional analysis of PdeNAC2 and AtVND6 in the tracheary element formation.

Tracheary elements (i.e. vessel elements and tracheids) are highly specialized, non-living cells present in the water-conducting xylem tissue.

Sulfur-DMSO promoted oxidative coupling of active methylhetarenes with amines: access to amides.

The elemental sulfur-DMSO couple was found to efficiently promote the oxidative coupling of active methylhetarenes with amines to yield amides under simple heating conditions. When 2-methylquinoline was used as the methylhetarene component, the formation of the expected 2-quinolinecarboxamides from anilines could be efficiently catalyzed by iron, nickel and cobalt salts. The method displayed good functional group tolerance and was applicable to aromatic, heteroaromatic and aliphatic amines.

Fe/S-Catalyzed synthesis of 2-benzoylbenzoxazoles and 2-quinolylbenzoxazoles via redox condensation of o-nitrophenols with acetophenones and methylquinolines.

An Fe/S catalyst generated in situ from FeCl·4HO and elemental sulfur S in the presence of a tertiary amine as a base was found to catalyze efficiently a 6e redox condensation of o-nitrophenols with acetophenones and methylquinolines. The condensed products 2-benzoylbenzoxazoles and 2-quinolylbenzoxazoles were obtained in reasonable yields with water as the only byproduct at a temperature as low as 80 °C.

Mycosporine-Like Amino Acids (MAAs) in Time-Series of Lichen Specimens from Natural History Collections.

Mycosporine-like amino acids (MAAs) were quantified in fresh and preserved material of the chlorolichen var. (Verrucariaceae/Ascomycota). The analyzed samples represented a time-series of over 150 years.