Bruce R. Whittlesey

Synthesis and crystal structures of lower rim amine and carbamoyl substituted calixarenes as transfer agents for oxyanions between an aqueous and a chloroform phase

Abstract The calixarene amides 5,11,17,23- tert -butyl-25,27-(carbamoylmethoxy) calix[4]arene 1 , 5,11,17,23- tert -butyl-25,27-( N , N -diethyl-2-carbamoylmethoxy) calix[4]arene 3 , 5,11,17,23- tert -butyl-25,27-methoxy-26,28-( N , N -diethyl-2-carbamoylethoxy) calix[4]arene.sodium triiodide 5 , 5,11,17,23- tert -butyl-25,27-propoxy-26-( N , N -diethyl-2-carbamoylmethoxy) calix[4]arene 6 , 5,11,17,23- tert -butyl-25,26,27,28-(carbamoylmethoxy) calix[4]arene 9 , 5,11,17,23- tert -butyl-25,26,27,28-( N , N -diethyl-2-carbamoylmethoxy) calix[4]arene.sodium iodide 11 and 5,11,17,23,29,35- tert -butyl-37,38,39,40,41,42-(carbamoylmethoxy) calix[6]arene 13 have been prepared by reacting the precursor calixarene with either 2-bromoacetamide or 2-chloro- N , N -diethylacetamide. The structures of 5 and 11 have been verified by X-ray crystallography. The crystals of 5 , C 58 H 74 I 3 N 2 NaO 6 , are monoclinic, P 2 1 / c , and those of 11 , C 71 H 112 IN 4 NaO 11 , are triclinic P 1 . The calixarene amines 5,11,17,23- tert -butyl-25,27-(2-aminoethoxy) calix[4]arene 2 , 5,11,17,23- tert -butyl-25,27-( N , N -diethyl-2-aminoethoxy) calix[4]arene 4 , 5,11,17,23- tert -butyl-25,27-propoxy-26-( N , N -diethyl 2-aminoethoxy) calix[4]arene 7 , 5,11,17,23- tert -butyl-25,27-methoxy-26-( N , N -diethyl 2-aminoethoxy) cal[4]arene 8 , 5,11,17,23- tert -butyl-25,26,27,28-(2-aminoethoxy) calix[4]arene hydrochloride 10 , 5,11,17,23- tert -butyl-25,26,27,28-( N , N -diethyl-2-aminoethoxy) calix[4]arene hydrochloride 12 and 5,11,17,23,29,35- tert -butyl-37,38,39,40,41,42-(2-aminoethoxy) calix[6]arene 15 have been synthesized by the borane reduction of either the precursor amide or cyanomethoxy derivative. The structure of 10 has been verified by X-ray crystallography. The crystals of 10 , C 56 H 94 Cl 2 N 4 O 10 , are triclinic, P 1 . The calix[4]arenes 2 , 3 , 4 , 6 , 10 , 11 and 12 have been investigated as extractants for the anions HPO 4 2− , SeO 4 2− , VO 3 − , ReO 4 − , CrO 4 2− , WO 4 2− and MoO 4 2− from water into a chloroform layer. Measurement of the remaining metal content in the aqueous layer by ICP has been used to obtain the distribution coefficient and percentage extraction into chloroform from solutions having a pH of both 0.85 and 7.0. These data generally show that the calix[4]arene amines are better extractants than the calix[4]arene amides, and that the former are usually better extractants from acidic solutions.

Bioactive Hydroperoxyl Cembranoids from the Red Sea Soft Coral Sarcophyton glaucum

A chemical investigation of an ethyl acetate extract of the Red Sea soft coral Sarcophyton glaucum has led to the isolation of two peroxide diterpenes, 11(S) hydroperoxylsarcoph-12(20)-ene (1), and 12(S)-hydroperoxylsarcoph-10-ene (2), as well as 8-epi-sarcophinone (3). In addition to these three new compounds, two known structures were identified including: ent-sarcophine (4) and sarcophine (5). Structures were elucidated by spectroscopic analysis, with the relative configuration of 1 and 2 confirmed by X-ray diffraction. Isolated compounds were found to be inhibitors of cytochrome P450 1A activity as well as inducers of glutathione S-transferases (GST), quinone reductase (QR), and epoxide hydrolase (mEH) establishing chemo-preventive and tumor anti-initiating activity for these characterized metabolites.

A Well‐Defined Monomeric Aluminum Complex as an Efficient and General Catalyst in the Meerwein–Ponndorf–Verley Reduction

The metal-catalyzed Meerwein-Ponndorf-Verley (MPV) reduction allows for the mild and sustainable reduction of aldehydes and ketones but has not found widespread application in organic synthesis due to the high catalyst loading often required to obtain satisfactory yields of the reduced product. We report here on the synthesis and structure of a sterically extremely overloaded siloxide-supported aluminum isopropoxide capable of catalytically reducing a wide range of aldehydes and ketones (52 examples) in excellent yields under mild conditions and with low catalyst loadings. The unseen activity of the developed catalyst system in MPV reductions is due to its unique monomeric nature and the neutral donor isopropanol weakly coordinating to the aluminum center. The present work implies that monomeric aluminum alkoxide catalysts may be attractive alternatives to transition-metal-based systems for the selective reduction of aldehydes and ketones to primary and secondary alcohols.

Synthesis of tert-butyl mercapto complexes of titanium(IV). X-ray crystal structure of Ti(diars)Cl2 (tBuS)2

Abstract The new class of tert-butyl mercapto compounds, Ti(L)Cl2(tBuS)2 (L = diars, dmpe, dppe), has been synthesized and characterized. The X-ray crystal structure of Ti(diars)Cl2(tBuS)2 (1) shows that the Ti(IV) atom has a distorted octahedral geometry with trans chlorides and cis tert-butyl mercapto units. The structures of the other complexes are similar based on spectroscopic (NMR, IR) evidence. Crystal data for (1): C18H34As2Cl2S2Ti, M = 583.24, trigonal space group P3121 (No. 152), a = b = 16.892(5) A, c = 8.492(2) A, U = 2098.4 A3, Z = 3, Dc = 1.389 gcm−3, μ = 29.841 cm−1, λ(MoKα) = 0.71069 A (graphite monochromator). Refinement of 948 observed (1371 unique measured; I > 3σ(I) reflections gave a final R = 0.0462 and Rw = 0.0597.

Xenophilic transition metal clusters

Abstract A new subset of the class of compounds containing polar metalmetal bonds is described in which two transition metals with open d-shells form a direct, unbridged bond between a metal center attached to π-acceptor ligands and one which is bound only to donor ligands that have no π-acceptor capabilities. The heterogeneous character of the metalmetal bond in these compounds is generated by the nature of the metal–ligand interactions, either with or without additional contributions from the differing identities and formal oxidation states of the metals. The clusters are remarkable in that they often exhibit unusually short metalmetal distances, and a number of them are highly paramagnetic. The term ‘xenophilic’ metal cluster has been proposed to refer to transition metal compounds that contain this type of metal–metal interaction. The group includes both heteronuclear ‘early–late’ transition metal clusters as well as homonuclear compounds in which the two metal centers are the same element, but differ in the type of ligands attached.

Lower Rim 2-Methylthioethoxy Substituted Calix[4]arenes as Shape Selective Complexants for Mercury and Silver

Abstract The compounds 5, 11, 17, 23-tert-butyl-25, 26, 27, 28-(2-methylthioethoxy)calix[4]arene 1 and 25, 26, 27, 28-(2-methylthioethoxy)calix[4]arene 2 have been synthesized from their corresponding 2-bromoethoxy derivatives. The crystal structure of 2 shows that the molecule has a flattened cone conformation. For the extraction of heavy metals from water into chloroform 1 and 2 show similar effectiveness for SnCl3 −, PdCl4 2-, PtCl4 2- and AuCl4 −, but for Hg2+ and Ag+, 2 is a better extractant than 1. This difference is discussed in terms of the relative hydrophobicities and structures of the two compounds

The reaction of phosphinyl radicals with 1,3-dienes

Abstract The stabilized radical, [(Me3Si)2CH]2P·, reacts with 1,3-dienes to afford 1,4-diphosphino-2-butenes.

Crystal structure and emission study of [(PPh3)2Cu(dmp)-O-(dmp)Cu(PPh3)2]2+ (dmp = 2,9-dimethyl-1,10-phenanthroline)

AbstractThe synthesis and crystal structure of a luminescent dinuclear Cu(I) complex as the BF−4 salt from toluene and methanol containing triphenylphosphine and μ-oxo-bis(2,9-dimethyl-1,10-phenanthroline) is described. The coordination geometry about the Cu(I) center is distorted tetrahedral. An unusual feature of the structure is a pseudo-inversion center located near the oxygen atom at approximately 0.51, 0.26, 0.25, such that all of the atoms except for the oxygen are related by a pseudo-inversion center to another atom in the same molecule, as well as by crystallographic inversion to the other molecule in the unit cell. The complex displays luminescence from an MLCT band in fluid solution and emission from both a metal-centered charge-transfer and intraligand (phenanthroline) state at 77K in a chloroform snow. Crystal data: triclinic, P

Reactivity of phosphenium ions toward 1,3- and 1,4-dienes

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