3β‐(1‐Allyl‐1‐pyrrolidinio)‐16‐(2‐pyridylmethylene)androst‐5‐en‐17β‐ol bromide hemihydrate

The title compound, C₃₂H₄₅N₂O⁺·Br^?·0.5H₂O, has the outer two six‐membered rings in chair conformations, while the central ring is in an 8β,9α‐half‐chair conformation. The five‐mem­bered ring of the steroid nucleus adopts a slightly deformed 14α‐envelope conformation. The pyridyl­methyl­ene moiety has an E configuration with respect to the hydroxyl group at position 17. The structure is stabilized by a network of O—H?Br‐type intermolecular hydrogen bonds.     

Progression of Organic Reactions on Resin Supports Monitored by Single Bead FTIR Microspectroscopy

We report the time courses of five solid-phase reactions obtained using single bead FTIR microspectroscopy. This time-resolved information aided in the determination of the required reaction time, the nature of the solid-phase reaction, and resin property, effectively assisting in the initial phase of our combinatorial chemistry efforts. Our results showed that solid-phase organic reactions proceed faster than generally speculated. In addition, we have shown that reactions on the surface and in the interior of the bead occur at the same rate for reactions studied. The reaction on the TentaGel resin was shown to be not faster than reactions on Wang resin, suggesting that the diffusion of the substrate into polystyrene bead copolymerized with 1% divinylbenzene is not rate-limiting. Finally, the capability of obtaining IR spectra from the partial surface of a single bead demonstrated the femtomolar detection limit of single bead FTIR microspectroscopy.     

Mechanism and linear free energy relationships in the kinetics of formation of bicyclo[3.3.1]nonane derivatives from 1,3,5‐trinitrobenzene,phenyl‐substituted 1‐benzyl‐1‐(ethoxycarbonyl)‐2‐propanones,and triethylamine

The kinetics and mechanism of cyclization of the anionic sigma complex obtained from the reaction of 1,3,5‐trinitrobenzene (TNB) and 1‐benzyl‐1‐(ethoxycarbonyl)‐2‐propanone (BEP) in the presence of triethylamine (NEt₃) have been studied in CH₃CN–CH₃OH (50% v/v). The order of the reaction has been found to be zero in TNB and BEP, unity in NEt₃, and negative and nonintegral in triethylammonium chloride. The rate has been observed to increase slightly with an increase in the concentration of the added salt (tetraethylammonium chloride). The rate constants for the formation of bicyclic adducts from phenyl‐substituted BEP and TNB in the presence of triethylamine have been correlated with σ values. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 467–473, 2011     

On a continued fraction of order six

In this paper, we derive certain identities for the following continued of order six:     

17‐Oxo‐16‐(2‐pyridyl­methyl­ene)­androst‐5‐en‐3β‐ol monohydrate

The title compound, C₂₅H₃₁NO₂·H₂O, has the outer two six‐membered rings in chair conformations, while the central ring is in an 8β,9α‐half‐chair conformation. The five‐membered ring adopts a 13,14‐half‐chair conformation. The pyridyl­methyl­ene moiety has an E configuration with respect to the carbonyl group at position 17. The structure is stabilized by intermolecular O—H?N and O—H?O hydrogen bonds.     

Synthesis,spectroscopic characterization and crystal structure of 5-bromo-1-(2-cyano-pyridin-4-yl)-1H-indazole-3-carboxylic acid diethylamide

The title compound 5-bromo-1-(2-cyano-pyridin-4-yl)-1H-indazole-3-carboxylic acid diethylamide, C₁₈H₁₆BrN₅O, is prepared from 5-bromoindazole-3-carboxylic acid methylester. N ¹-arylation is carried out with 4-chloro-2-cyanopyridine and the resulting product is converted to diethylamide by reacting with thionyl chloride and diethylamine. The structure is identified from its FT-IR, ¹H NMR, ¹³C NMR spectroscopy, elemental analysis data and unambiguously confirmed by single crystal X-ray diffraction studies. There are two symmetry independent molecules in the asymmetric unit with no significant differences in bond lengths and angles. The title compound crystallizes in the triclinic system, space group \(P\bar 1\) , with a = 11.2330(2); b = 11.6130(2); c = 15.4710(3) Å, α = 92.515(1)°; β = 109.956(1)°; γ = 107.199(1)°; V = 1788.45(6)ų and z = 4. An intramolecular C-H…N hydrogen bond forms an S(6) ring motif in one of the unique molecules. In the crystal, two molecules are linked about a center of inversion by C-H…O hydrogen bonded dimers generating an R ₂ ² (16) ring motif. The crystal packing is stabilized by C-H…N, C-H…O hydrogen bonds and π…π stacking interactions.     

4‐(3,17‐Dioxoandrost‐4‐en‐16‐ylidenemethyl)benzonitrile

The title compound, C₂₇H₂₉NO₂, has the outer six‐membered ring in a sofa conformation, while the central rings are in chair conformations. The five‐membered ring adopts a slightly distorted 13β,14α‐half‐chair conformation. The cyano­benzyl­idene moiety has an E configuration with respect to the carbonyl group at position 17.     

Novel solvent properties of choline chloride/urea mixtures

Eutectic mixtures of urea and a range of quaternary ammonium salts are liquid at ambient temperatures and have interesting solvent properties.     

On Somos’s theta-function identities of level 14

M. Somos discovered around 6200 theta-function identities of different levels using the computer and offered no proof for them. The purpose of this paper is to prove twenty four of his identities of level 14.