In the present work, we have developed a mild, efficient, and environmentally benign method for the synthesis of tetrahydrobenzo[b]pyran derivatives via a three-component cyclocondensation of aldehydes, malononitrile and dimedone utilizing ammonium chloride as a simple, easily available and cost effective catalyst under microwave irradiation. This method has several attracting features such as ...

p-Dodecylbenzenesulfonic acid (DBSA) was used as a catalyst for a simple and efficient one-pot synthesis of aryl substititued tetrahydrobenzo[b]pyrans and dihydropyrano[c]chromens via initial Knoevenagel, subsequent Micheal and final heterocyclization reactions of aryl aldehyde, malononitrile and 4-hydroxycoumarin/dimedone in moderate to excellent yields. The present method was operationally si...

In the present work, we have developed a mild, efficient, and environmentally benign method for the synthesis of tetrahydrobenzo[b]pyran derivatives via a three-component cyclocondensation of aldehydes, malononitrile and dimedone utilizing ammonium chloride as a simple, easily available and cost effective catalyst under microwave irradiation. This method has several attracting features such as ...

simple harmonizable processes (shp) introduced by soltani and parvardeh (2006) are a large class of nonstationary processes which includes stationary and periodically correlated (pc) processes. detection and estimation of shp structure are important problems when dealing with nonstationary data. in this paper, we study the spectral properties of simple processes and propose a method to detect a...

the pre.sent rep.or,t describes the morphological and if nod h pron erative aspects of lymph es iii odgkin s disease grown in tissue culture. the development of hodgkin's lymph-nodes grown in vitro seems to depend upon the  a~e of t~e person and the stage of the hodgkin's disease at the time the i h is obtained. ymp - the morphological and the proliferative aspects ('helralcterizi~d of hodgkin'...

this article aims at contrasting aspectual oppositions in english and persian in the context of the novel the old man and the sea, and its translation by daryabandari (1983) as the data. unlike english, in persian perfective and imperfective forms are morphologically marked. while the vast majority of english simple past forms are translated into persian by past perfective forms, only less than...