Synthesis of Diarylheptanoid Scaffolds Inspired by Calyxins I and J

γ,δ-Unsaturated alcohols are prepared efficiently in two steps from <i>o</i>-hydroxycinnamaldehyde. The TMSOTf-mediated reaction of the γ,δ-unsaturated alcohols with aldehydes creates two oxygen heterocycles and three new stereocenters in a single pot. The approach is versatile, and by varying the boronic acid, Grignard reagent, and aldehyde, different substituents may be introduced, while use of a chiral base in the conjugate addition gives enantioenriched products

Selected solid-state behaviour of three di-tert-butyl-substituted N-salicylideneaniline derivatives: temperature-induced phase transitions and chromic behaviour

The synthesis, single-crystal structures and chromic behaviour of three related Schiff bases, namely, (E)-2,4-di-tert-butyl-6-{[(4-fluoro­phen­yl)imino]­meth­yl}phenol, C21H26FNO, 1, (E)-2,4-di-tert-butyl-6-{[(4-chloro­phen­yl)imino]­meth­yl}phenol, C21H26ClNO, 2, and (E)-6-{[(4-bromo­phen­yl)imino]­meth­yl}-2,4-di-tert-butyl­phenol, C21H26BrNO, 3, are reported. Two polymorphs of 1 were obtained, which were found to have different photochromic properties. Schiff bases 2 and 3 were found to be isostructural and underwent a phase transition upon cooling which was attributed to the dynamic disorder in one of the tert-butyl groups resolving at low temperature. All of the structures were found to exist in the enol rather than the keto form based on the C—O(H) and imine C=N bond lengths, and contained an intra­molecular O—H⋯N hydrogen bond alongside weaker inter­molecular C—H⋯O contacts

(E)-4-Bromo-2-[(phenylimino)methyl]phenol: a new polymorph and thermochromism

A new polymorph of (E)-4-bromo-2-[(phenylimino)methyl]phenol, C13H10Br-NO, is reported, together with a low-temperature structure determination of thepreviously published polymorph. Both polymorphs were found to have anintramolecular O—HN hydrogen bond between the phenol OH group andthe imine N atom, forming an S (6) ring. The crystals were observed to havedifferent colours at room temperature, with the previously published polymorphbeing more orange and the new polymorph more yellow. The planarity of themolecule in the two polymorphs was found to be significantly different, withdihedral angles () between the two aromatic rings for the previously published‘orange’ polymorph of = 1.8 (2)at 120 K, while the new ‘yellow’ polymorphhad = 45.6 (1)at 150 K. It was also observed that both polymorphs displayedsome degree of thermochromism and upon cooling the ‘orange’ polymorphbecame more yellow, while the ‘yellow’ polymorph became paler upon cooling

Evaluasi Padang Penggembalaan Alami Maronggela Di Kabupaten Ngada Provinsi Nusa Tenggara Timur

&nbsp;Evaluasi terhadap padang penggembalaan alami untuk memperbaiki kualitas hijauan merupakan salah satustrategi penting dalam peningkatan produksi ternak ruminansia. Penelitian ini bertujuan untuk menyediakandatabase tentang kondisi padang penggembalaan serta pengelolaan padang penggembalaan yang baik di KabupatenNgada. Kabupateng Ngada merupakan daerah yang sangat potensial bagi pengembangan ternak sapi karenamemiliki padang penggembalaan yang luas. Penelitian dilakukan di padang penggembalaan alami MaronggelaKabupaten Ngada, Provinsi Nusa Tenggara Timur, yang berlangsung selama 2 musim, yaitu pada akhir musimhujan (bulan Maret) dan akhir musim kemarau (bulan Oktober). Peubah yang diamati pada penelitian ini adalahkomposisi botani dan kualitas hijauan. Padang penggembalaan alami Maronggela didominasi oleh hijauan jenisImperata cylindrica dan Themeda aguens, produksi dan kualitas hijauan tertinggi di akhir musim hujan, sertaproduksi dan kualitas terendah di akhir musim kemarau. Daya tampung padang penggembalaan alami Maronggeladalam satu tahun adalah 1,5 satuan ternak. Kata kunci: database, padang pengembalaan, sap