Neogene rotations in the Jiuquan Basin, Hexi Corridor, China

<p>Vertical-axis rotations of blocks in/around the Tibetan Plateau can be attributed to the India–Asia collision. Study of the vertical-axis rotations of these blocks will increase our understanding of the mechanisms and kinematics of continent–continent collisions. We report here a new palaeomagnetic study of rotations using data from four localities (five magnetostratigraphy sections) in the Jiuquan Basin. Our study indicates that the mean declinations of each section are different from each other, similar to what has been observed in the other localities in the NE Tibetan Plateau. However, using the mean directions of every 100 m of section, we observe that the four localities have similar sequential patterns of rotations during the last 13 Ma: significant continuous counterclockwise before <em>c.</em> 8.0 Ma, insignificant rotations between 8.0–4.0 Ma, and slight clockwise rotation after 4.0 Ma. This indicates that, rather than being a record of spatially varying declinations, it is a temporal variation in the occurrence of regional rotations. Combined with other geological evidence, the rotation patterns may suggest two major tectonic activity phases of the northeastern Tibetan Plateau during the last 13 Ma: an eastward extrusion and strike-slip dominant phase before 8.0 Ma, a significant shortening and a rapid uplift dominant phase after 8.0 Ma. </p

Base-Mediated Synthesis of Unsymmetrical 1,3,5-Triazin-2-amines via Three-Component Reaction of Imidates, Guanidines, and Amides or Aldehydes

A simple and efficient method for the base-mediated synthesis of unsymmetrical 1,3,5-triazin-2-amines has been developed. The protocol uses readily available imidates, guanidines, and amides or aldehydes as the starting materials, cesium carbonate as the base, no catalyst or additive is required, and the three-component reaction provides diverse 1,3,5-triazin-2-amines in moderate to good yields with tolerance of wide functional groups

Late Oligocene monsoonal climate in the Lunpola Basin, central Tibetan Plateau: evidence from paleosol records

Supplementary data 2

Late Oligocene monsoonal climate in the Lunpola Basin, central Tibetan Plateau: evidence from paleosol records

Supplementary data 1

Copper-Catalyzed One-Pot Synthesis of 1,2,4-Triazoles from Nitriles and Hydroxylamine

A simple and efficient copper-catalyzed one-pot synthesis of substituted 1,2,4-triazoles through reactions of two nitriles with hydroxylamine has been developed. The protocol uses simple and readily available nitriles and hydroxylamine hydrochloride as the starting materials and inexpensive Cu­(OAc)₂ as the catalyst, and the corresponding 1,2,4-triazole derivatives are obtained in moderate to good yields. The reactions include sequential intermolecular addition of hydroxylamine to one nitrile to provide amidoxime, copper-catalyzed treatment of the amidoxime with another nitrile, and intramolecular dehydration/cyclization. This finding provides a new and useful strategy for synthesis of 1,2,4-triazole derivatives

Copper-Catalyzed One-Pot Synthesis of 1,2,4-Triazoles from Nitriles and Hydroxylamine

A simple and efficient copper-catalyzed one-pot synthesis of substituted 1,2,4-triazoles through reactions of two nitriles with hydroxylamine has been developed. The protocol uses simple and readily available nitriles and hydroxylamine hydrochloride as the starting materials and inexpensive Cu­(OAc)₂ as the catalyst, and the corresponding 1,2,4-triazole derivatives are obtained in moderate to good yields. The reactions include sequential intermolecular addition of hydroxylamine to one nitrile to provide amidoxime, copper-catalyzed treatment of the amidoxime with another nitrile, and intramolecular dehydration/cyclization. This finding provides a new and useful strategy for synthesis of 1,2,4-triazole derivatives

Nmp-based ionic liquids: Recyclable catalysts for both hetero-Michael addition and Knoevenagel condensation in water

<p>A series of novel <i>N</i>-methyl piperidine (Nmp)-based ionic liquids with 1,2-propanediol group are synthesized and used as catalysts for both hetero-Michael addition of α,β-unsaturated amides and Knoevenagel condensation at room temperature in water; and all the examined substrates could be transformed into corresponding products in good to excellent yields. Meanwhile IL-catalyzed hetero-Michael addition of α,β-unsaturated amides in water has not been reported in the previous literatures. Additionally, the catalyst is recyclable for the two reactions. This finding provides a green catalyst for both hetero-Michael addition of α,β-unsaturated amides and Knoevenagel condensation in water.</p