The development of multicomponent reactions (MCRs) designed to produce elaborate biologically active compounds has become an important area of research in organic, combinatorial, and medicinal chemistry. A comparative study of the synthesis of new bis-spiro-oxindolo(pyrrolizidines/pyrrolidines) ring systems by the cycloaddition of azomethine ylides generated by a decarboxylative route from sarc...

We report the crystal structure and hole-transport mechanism in spiro-OMeTAD [2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9'-spirobifluorene], the dominant hole-transporting material in perovskite and solid-state dye-sensitized solar cells. Despite spiro-OMeTAD's paramount role in such devices, its crystal structure was unknown because of highly disordered solution-processed films; the ho...

The tert-amino reaction effect was examined. A new method to synthesize spiro heterocycles is presented. It was shown that the "tert-amino effect" could be applied to the formation of spiro-fused heterocycles. The formation of spiro compounds proceeds in most cases in good yields in a one-pot reaction.

Accumulating evidence indicates that aldosterone plays a critical role in the mediation of oxidative stress and vascular damage. NADPH oxidase has been recognized as a major source of oxidative stress in vasculature. However, the relation between NADPH oxidase in aldosterone-mediated oxidative stress in endothelial cells remains to be ascertained. The present study aimed to investigate the rele...

A mutant strain of Neurospora crassa blocked in each of the initial steps of tryptophan, tyrosine, and phenylalanine biosynthesis was previously shown to accumulate and secrete prephenate and L-arogenate (Jensen, R.A., Zamir, L.O., St. Pierre, M., Patel, N., and Pierson, D.L. (1977) J. Bacteriol. 132, 896-903). We now report the co-accumulation of yet another compound which was identified (Zami...

In the presence of triethylamine as catalyst, the one-pot four-component reactions of arylamines, methyl propiolate, isatin and malononitrile afforded the functionalized spiro[indoline-3,4'-pyridine] derivatives in good yields. Similar reactions with ethyl cyanoacetate successfully afforded the functionalized spiro[indoline-3,4'-pyridines] and spiro[indoline-3,4'-pyridinones] as the main produc...

The reactions of isatins, 3-amino-1-pheyl-1H-pyrazol-5(4H)-one, and monocyclic ketones, have been developed for preparation spiro[indoline-3,4'-pyrazolo[3,4-b]quinoline]-2,3'(6'H)-dione, spiro[cyclohepta[b]pyrazolo[4,3-e]pyridine-4,3'-indoline]-2′,3-dione, spiro[cycloocta[b]pyrazolo[4,3-e]pyridine-4,3'-indoline]-2′,3(6H)-dione, spiro[cyclo dodeca[b]pyrazolo[4,3-e]pyridine-4,3'-indoline]-2′,3(6H...

In the presence of water and amines etherate bicyclic Al2(OSiPh2OSiPh2O)3 (II a) can be used to generate novel alumosiloxane polycycles like [O(Ph2SiOSiPh2)O−]2Al2O[O(Ph2SiOSiPh2)O] ⋅ 2 H2N+Et2 (1), [O(Ph2SiOSiPh2)O−]2Al2[O(Ph2Si)O]2 HN+Et3 (2), [O(Ph2SiOSiPh2)O−]2Al2[O(Ph2SiOSiPh2)O]2 (3 a, 3 b), which crystallizes in two different phases, HN+(CH2CH2)3N (4). As a common structural feature thes...

Spiro-bis-dithiepins are synthesized via dehydrative ring expansion in alpha-hydroxyalkyl spiro-bis-dithianes. Atypical of spiranes possessing axial chirality, the two most stable conformers of substituted spiro-bis-dithiepin have virtually colinear double bonds; i.e., each enantiomer exists in a form of two energy degenerate syn and anti conformations. Because of the high polarizability of the...

We have revisited the photochromic spiro-dihydroindolizine/betaine (DHI/B) system applying state-of-the-art density functional theory (DFT) calculations in combination with stationary and time-resolved absorption measurements. DHI/B-systems are becoming increasingly important as potential molecular machines, molecular switches, and photoswitchable electron-acceptors. The knowledge of the exact ...