Trichoderma is environmentally vital due to their plant growth-promoting effects (such as enhancement of nutrients supply, suppression of plant pathogens, and promotion of plant defense). Biogenic volatile organic compounds (VOCs) are diverse chemical substances emitted by Trichoderma spp. The potential role of VOCs in biological control and plant growth promotion has recently been recognized. Here, the Trichoderma-VOCs' performance for plant growth promotion and suppression of plant pathogens are evaluated. We further investigated VOC emission profiles of T. harzianum using GC–MS. The Trichoderma-VOCs exhibited significant (p < 0.05) antifungal properties against all tested pathogenic fungi. T. atroviride-VOCs showed a decisive inhibition of Alternaria panax, Botrytis cinerea, Cylindrocarpon destructans, and Sclerotinia nivalis. The germinating seeds demonstrated growth enhancement in the presence of Trichoderma-VOCs emitted by different strains. Low levels of cyclopentasiloxane, decamethyl, cyclotetrasiloxane, and octamethyl were found in T. harzianum KNU1 strain whereas cyclopentasiloxane, decamethyl, cyclotetrasiloxane, and octamethyl showed higher emission levels as Si-containing compounds. The results reveal the potentiality of VOCs as a biocontrol resource against deleterious rhizosphere microorganisms and underline the importance of Trichoderma-VOCs emissions in regulating plant growth and development.

Our present study provides expedient methods for the synthesis of novel substituted indanes, pyrido[3,2,1- jk]carbazoles and pyrido[3,2,1-kl]phenothiazines utilizing intramolecular Friedel-Crafts cyclialkylations of synthesized heteroaryl alcohols. This methodology is realized by a three-step protocol involving first esterification of starting carboxylic acids to the corresponding esters, addition of Grignard reagents to give carbinol precursors and followed by Friedel-Crafts cyclizations of alcohols mediated by AlCl3/CH3NO2, PPA or P2O5-catalysts to furnish the desired polycycles in good to excellent yields of 65-85%. The designed protocol offers easy access to the pharmaceutically promising templates in good yields. The molecular structural elucidations of all newly obtained compounds have been proved by spectral and elemental analysis.

An efficient access to benzo[b]thiophene-fused or -bridged to medium-sized N-heterocycles e.g. azocinones,
azoninones and azecinones, is described. The process involves cyclization of benzo[b]thiophene carboxylic
ester precursors, mediated by Lewis and Brønsted acids under suitable conditions. The ring closure precursors
were assembled starting from 2-acetylbenzo[b]thiophene. The developed strategy allows control of ring size
and offers easy access to fused benzo[b]thiophene polycycles of promising biological importance in moderate
to good yields.