Three tetrahydroisoquinolinedione derivatives

N‐(2‐Chloro­benzyl)‐1,2,3,4‐tetra­hydro­iso­quinoline‐1,3‐dione, C₁₆H₁₂ClNO₂, crystallizes in P2₁/n with three crystallographically independent mol­ecules in the asymmetric unit, which differ slightly in conformation, N‐(2‐bromo‐4‐methyl­phenyl)‐1,2,3,4‐tetra­hydro­iso­quinoline‐1,3‐dione, C₁₆H₁₂BrNO₂, crystallizes in P2₁/n with one mol­ecule in the asymmetric unit andN‐(2,3‐di­chloro­phenyl)‐1,2,3,4‐tetra­hydro­iso­quinoline‐1,3‐dione, C₁₅H₉Cl₂NO₂, crystallizes in P2₁/c with one mol­ecule in the asymmetric unit. In all three structures, the heterocyclic rings adopt approximately planar conformations. The pyridine rings are orthogonal to the substituted phenyl rings. In all three structures, the crystal packing is stabilized by intermolecular C—H?O hydrogen bonds.     

Heat Capacities of Three Isomeric Chlorobenzenes and of Three Isomeric Chlorophenols

Isobaric heat capacities C _p in the liquid and in the solid phase of 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,4-trichlorobenzene, 3-chlorophenol and 4-chlorophenol and in the liquid phase of 2-chlorophenol were measured by commercial Setaram heat conduction and power compensated calorimeters. Results obtained cover the following temperature range (depending on the compound and state of aggregation): 1,2-dichlorobenzene 208 to 323 K,1,3-dichlorobenzene 183 to 323 K, 1,2,4-trichlorobenzene 133 to 323 K, 2-chlorophenol from293 to 353 K, 3-chlorophenol and 4-chlorophenol from 133 to 353 K. The heat capacity data obtained in this work were merged with available experimental data from literature, critically assessed and sets of recommended data were developed by correlating selected data as a function of temperature. Temperature and enthalpy of fusion of two isomeric chlorophenols and of 1,2,4-trichlorobenzene were also determined. This revised version was published online in August 2006 with corrections to the Cover Date.     

Three leflunomide metabolite analogs

The title compounds, 1‐cyano‐2‐hydroxy‐N‐[4‐(methylsulfon­yl)phenyl]but‐2‐en­amide, C₁₂H₁₂N₂O₄S, PHI492, 1‐cyano‐2‐hydroxy‐N‐[3‐(methyl­sulfonyl)­phenyl]­but‐2‐en­amide, C₁₂H₁₂­N₂O₄S, PHI493, and N‐[3‐bromo‐4‐(trifluoro­methoxy)­phenyl]‐1‐cyano‐2‐hydroxybut‐2‐en­amide, C₁₂H₈Br­F₃N₂O₃, PHI495, are potent inhibitors of Bruton's tyrosine kinase (BTK). The molecular structures of these compounds are similar and they display similar hydrogen‐bonding networks and crystal packing. Examination of the crystal‐packing interaction in the three compounds reveals an alternating direction of adjacent mol­ecules in the crystalline lattice due to intermolecular cyano–amide hydrogen bonding. PHI492, a positional isomer of PHI493, does not form intermolecular O—H?O hydrogen bonds between mol­ecules and crystallizes in a space group different from that of PHI493 and PHI495. The aromatic ring and the amide group of each mol­ecule form a conjugated π‐system which ensures planarity, with further stabilization gained from intramolecular O—H?O hydrogen bonds.     

蛋壳实验三则

二氧化碳的制取,取一鹅蛋,小心在一端打上一个直径为1cm的小洞,用玻璃棒小心搅拌,让蛋黄蛋清流出,注入水清洗。蛋壳的主要成分是碳酸钙。     

Three trithiadiazepines and a trithiatriazepine

The structures of 6‐nitro‐1,3λ⁴δ²,5,2,4‐trithiadiazepine [C₂HN₃O₂S₃, ( 1 )], 6,7‐dinitro‐1,3λ⁴δ²,5,2,4‐trithiadiazepine [C₂N₄O₄S₃, ( 2 )], 1,3λ⁴δ²,5,2,4‐trithiadiazepine‐6,7‐dicarbonitrile [C₄N₄S₃, ( 3 )] and 7‐acetyl‐1,3λ⁴δ²,5,2,4,6‐trithiatriazepine [C₃H₃N₃OS₃, ( 4 )] presented here include the most precise determinations of these seven‐membered 10 π‐electron aromatic ring systems published to date. Both ( 2 ) and ( 3 ) are sited around crystallographic twofold axes with half a molecule per asymmetric unit. Comparison with other published derivatives of these rings reveals the effect of substituents on bonding, conformations and intermolecular interactions, including π‐stacking. The deformation density analysis of ( 2 ) is consistent with the expected bonding electron density from other theoretical and experimental studies.     

Three new ZnII sulfate complexes

The three zinc sulfate complexes presented herein display three completely different coordination modes, viz tri­aqua(1,10‐phenanthroline‐N,N′)(sulfato‐O)­zinc(II) hydrate, [Zn(SO₄)(C₁₂H₈N₂)(H₂O)₃]·H₂O (octahedral, monomeric), bis(μ‐sulfato‐O:O′)­bis[(2,9‐di­methyl‐1,10‐phenanthroline‐N,N′)­zinc(II)], [Zn₂(SO₄)₂(C₁₄H₁₂N₂)₂] (tetrahedral, dimeric), and catena‐poly­[[di­aqua(2,2′‐bipyridyl‐N,N′)­zinc(II)]‐μ‐(sul­fato‐O:O′)], [Zn(SO₄)(C₁₀H₈N₂)(H₂O)₂]_n (octahedral, polymeric, twofold crystallographic symmetry). In the first, the sulfate is monodentate, while in the other two it acts as a bidentate bridge between two different Zn centers. There is a variety of sulfate S—O bond lengths, depending on the different coordination conditions and hydrogen‐bonding interactions.     

Three New Types of Cyclotriphosphates

Abstract

The present work is more intended to illustrate three very different ways for the preparation of cyclotriphosphates than to describe three new types of such compounds.     

One Setup, Three Systems

The system—surroundings concept is one of the most important in thermodynamics. Precisely defining a system is of critical importance to thermodynamic analysis. Even when studying the same problem, different individuals may opt to select different systems; therefore, choosing the correct system requires skill. In order to help students understand the various systems and their differences, a simple distillation setup is used to demonstrate the three thermodynamic systems: open, closed, and isolated.     

Three chiral vinyldioxaza­borocanes

The structures of three chiral vinyldioxaza­borocanes are reported, namely (2E)‐ and (2Z)‐6‐benzyl‐2‐buten‐2‐yl‐1,3,6,2‐dioxaza­borocane, C₂₇H₃₀BNO₂, (II) and (III), respectively, and (2Z)‐2‐buten‐2‐yl‐6‐isobutyl‐1,3,6,2‐dioxaza­boro­cane, C₂₄H₃₂BNO₂, (IV). These compounds may be useful in asymmetric reactions. In the structures reported here, the N—B donor–acceptor bond is longer than in any previously reported analogous compounds.