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Research of thermally activated delayed fluorescence (TADF) and room‐temperature phosphorescence (RTP) materials is attractive owing to their extensive applications in various fields. However, achieving organic TADF and RTP materials, particularly those with stimulus‐responsiveness and tunability, is highly desirable but challenging and rarely reported. Herein, two easily synthesized organic molecules are reported with abnormal stimulus‐responsive switchable TADF and RTP effects, in which phenothiazine (PTZ) and benzo[b]phenothiazine (BPTZ) based donor−acceptor molecules PTZ‐DBQ and BPTZ‐DBQ show mechanical‐induced TADF in crystalline phase and photo‐responsive RTP in doping poly(methyl methacrylate) (PMMA) films. This is the first time tetracyclic BPTZ has been used as a donor in achieving TADF and RTP materials, and it is found that BPTZ‐DBQ exhibits remarkably better photophysical properties than PTZ‐DBQ. Systematic studies of experimental results and theoretical calculations indicate that the conformational heterogeneity plays an essential role in achieving mechanical‐induced TADF with mechanochromic luminescence (MCL) property. Embedding the organic phosphors into rigid polymer matrices effectively suppresses the molecular motion, thus turning on the RTP emission channel. The conversion of 3O2 to 1O2 under UV irradiation is mainly responsible for the photo‐induced process. These multifunctional luminescent materials have great potential applications in chemical sensors, information encryption, and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

Poly‐p‐phenyleneterephthalamide (PPTA) is widely used in national defense, military industry, and aerospace. However, with weak compression resistance and twist resistance, development of PPTA is greatly impeded. In this work, a novel rigid rod polymer was synthesized by polycondensation of 2,6‐dihydroxyterephthalic acid with 2,3,5,6‐tetraminopyridine which have a large quantity of hydrogen bonds between these polymer chains which provide excellent thermal properties named poly [N‐(2,5‐diamino‐6‐[imino]‐3‐pyridyl)‐4‐formyl‐2,6‐dihydroxybenzamide] (PPDA). The structure of the polymers was characterized by X‐ray diffraction and Fourier transform infrared spectroscopy. The resulting showed that PPDA has good thermal stability and crystallinity, the maximum thermal decomposition temperature close to 900°C under the nitrogen atmosphere. At the same time, PPDA was insoluble in most organic solvents and exhibited good chemical stability. This indicated a superior performance over that of the poly(2,6‐diimidazo(4,5‐b:4′5′‐e)pyridinylene‐1,4(2,5‐dihydroxy)phenylene). In addition, we can foresee that PPDA will play an important role in prospective surgery and aramid areas. [ABSTRACT FROM AUTHOR]

Sterculia lanceolata, an important tropical woody plant, has high ornamental and medicinal value. To our knowledge, only brown root disease in this plant has been reported. In Nanning, Guangxi, China, an outbreak of leaf blight disease was observed on S. lanceolata in June 2019, with the leaf infection rate ranging from 80% to 100%. The disease seriously affected the leaves of trees and caused economic loss. Eight isolates were recovered from the infected leaves of different trees, and the pathogenicity was then determined by the methods of mycelial disc and conidial suspension, fulfilling Koch's postulates. According to the morphological and molecular biological characteristics of isolates, the pathogen causing leaf blight on S. lanceolata was identified as Colletotrichum siamense. Accurate identification of the pathogen provides a reliable basis for the control of the disease. [ABSTRACT FROM AUTHOR]

The nicotinic acetylcholine receptor (nAChR) is one of the targets for developing drugs for the treatment of central nervous system (CNS) disorders and for control of agricultural pests. Pyrido[3,4‐b] homotropane (PHT) was originally designed and synthesized by Kanne and co‐workers and showed strong affinity binding to nAChR. PHT has a novel aza‐[4.2.1]nonane skeleton. Owing to its excellent biological activities and novel chemical structure, synthetic and medicinal chemists have been attracted by this molecule. Some PHT analogues with bridged aza‐[n.2.1] skeletons were also designed and synthesized via different strategies. Herein, we summarize the syntheses of PHT and its analogues. Their biological activity study is also briefly discussed. [ABSTRACT FROM AUTHOR]

Abstract: An efficient synthesis of (−)‐pyrido[3,4‐b]homotropane (PHT) as well as (±)‐PHT has been achieved in 7 steps from conveniently available starting materials. Key transformations involve an efficient construction of the core bridged 9‐aza‐[4.2.1]nonane skeleton via a Sc(OTf)3‐catalyzed intramolecular cross [3+2] cycloaddition (IMCC) followed by Krapcho decarboxylation and Barton reductive decarboxylation. The present work supplies a general and efficient strategy for synthesis of other bridged analogues. [ABSTRACT FROM AUTHOR]

A novel Lewis acid-catalyzed [3+2] intramolecular cross-cycloaddition (IMCC) between aziridine 2,2-diesters and conjugated dienes has been developed. This is the first regiospecific IMCC of intramolecular 1,3-dipolar cycloadditions of azomethine ylides with carbon=carbon double bonds, and supplies a general and efficient strategy for construction of structurally complex and diverse aza-[ n.2.1] skeletons. The [3+2]IMCC could be carried out under mild conditions and in gram scale. More importantly, 3-alkyl-substituted aziridines were also successful. The excellent structural diversity, the facile operation and the versatile post-modifications will support the applications of the [3+2]IMCC in natural products synthesis and drugs discovery. [ABSTRACT FROM AUTHOR]

Aiming to develop efficient and general strategies for construction of complex and diverse polycyclic skeletons, we have successfully developed [4+3]IMPC (intramolecular parallel cycloaddition) of cyclopropane 1,1-diesters with [3]dendralenes. With a combination of the [4+3]IMPC and subsequent [4+ n] cycloadditions, trans-[5.3.0]decane skeleton and its corresponding structurally complex and diverse polycyclic variants could be constructed efficiently. This novel [4+3] cycloaddition reaction mode of donor-acceptor cyclopropanes proceeds as a result of the ring-strain relief of a trans-[3.3.0]octane. We strongly believe that the developed methods will demonstrate potential applications in natural products synthesis and drug discovery. [ABSTRACT FROM AUTHOR]

In contast to the general [4+2] cycloaddition reactions of alkynylcyclopropane ketones reported in the literature, we report herein a Sc(OTf)3-catalyzed formal intermolecular [3+2] cycloaddition reaction of alkynylcyclopropane ketones with electron-rich aromatic aldehydes. 2,3,3,5-Tetrasubstituted tetrahydrofurans were obtained by this method, and the tetrahydrofuran skeleton was diastereoselectively constructed with a 2,5- trans configuration. This is also quite different to the 2,5- cis configuration usually obtained from typical [3+2] cycloaddition reactions of most donor-acceptor cyclopropanes. Additionally, the cycloadducts were subjected to a domino carbopalladation/C-H activation/C-C bond-formation process for the highly efficient construction of polycyclic skeletons. [ABSTRACT FROM AUTHOR]

An acid-catalyzed domino Meinwald rearrangement of epoxides/intramolecular [3+2] cross-cycloaddition of cyclopropane 1,1-diesters was developed. This supplied a method for the construction of bridged oxa-[ n.2.1] ( n = 3, 4) skeletons. [ABSTRACT FROM AUTHOR]

Carbon bridges: The title reaction has been successfully developed, and applied to the total synthesis of the tetracyclic diterpenoids phyllocladanol and phyllocladene. The method provides an efficient, general, and conceptually new strategy for the construction of structurally complex and diverse [n.2.1] carbocyclic skeletons (see scheme). [ABSTRACT FROM AUTHOR]

Two new cytochalasins, 18-deoxycytochalasin Q ( 1) and 21- O-deacetylcytochalasin Q ( 2), together with four known analogues, cytochalasin Q ( 3), 19,20-epoxycytochalasin Q ( 4), 21- O-deacetyl-19,20-epoxycytochalasin Q ( 5), and cytochalasin D ( 6), were isolated from the fungus Xylaria sp. SCSIO156 originated from the South China Sea marine sediment. The structures of 1 and 2 were elucidated by MS and 1D- and 2D-NMR data analyses, and comparison with known compounds. The known compounds 3- 6 were identified by comparison of their MS and NMR data with those reported in the literature. In the in vitro antitumor assay, compounds 2- 6 showed mild cytotoxicity against three tumor cell lines (MCF-7, SF-268, and NCI-H460). [ABSTRACT FROM AUTHOR]

A novel Lewis acid‐catalyzed [3+2] intramolecular cross‐cycloaddition (IMCC) between aziridine 2,2‐diesters and conjugated dienes has been developed, which supplies a general and efficient strategy for construction of structurally complex and diverse aza‐[n.2.1] skeletons. The excellent structural diversity, the facile operation and the versatile post‐modifications will support the applications of the [3+2]IMCC in natural product synthesis and drug discovery. “Three begets all things of the world” comes from “Daodejing”, an immortal classic composed by Laozi, a great philosopher and thinker of ancient China. In this chemistry, the three‐membered aziridine means the “three” which begets the diversity and complexity by the IMCC strategy. For the full story see the Communication by Z. Wang et al. on page 17862 ff. [ABSTRACT FROM AUTHOR]

Cycloadditions Developing efficient and general strategies for construction of skeletally complex and diverse polycyclic skeletons in natural products is important and challenging in organic synthesis. In their Communication on page 1231 ff., Z. Wang and co‐workers demonstrate a [4+3]IMPC (intramolecular parallel cycloaddition) of cyclopropane 1,1‐diesters with [3]dendralenes. With a combination of the [4+3]IMPC and subsequent [4+n] cycloadditions, bridged trans‐[5.3.0]decane skeleton and its corresponding structurally complex and diverse polycyclic ones are constructed efficiently. This strategy is believed to be of potential importance to natural product synthesis and drug discovery. [ABSTRACT FROM AUTHOR]

Review: ca. 100 refs. [ABSTRACT FROM AUTHOR]