4-Hydroxy-4,6a,6b,9,9,12a,14b-heptamethylperhydropicen-3-one hemihydrate isolated from Adiantum incisum

The title compound, C29H48O2·0.5H2O, is a triterpenoid isolated from the stems and rhizomes of Adiantum incisum. The basic skeleton of the mol­ecule contains five six-membered rings, all adopting chair conformations, bearing a total of seven methyl, one hydroxyl and a keto group. There are two mol­ecules of the triterpene and one water molecule of crystallization in the asymmetric unit. The two unique triterpenoid mol­ecules hydrogen-bond directly via an O—H⋯O=C inter­action, and are also bridged by the water mol­ecule. The water also bridges to another pair of hydrogen-bonded triterpenoid mol­ecules

2-Imino-3-(2-nitro­phen­yl)-1,3-thia­zolidin-4-one

In the title compound, C9H7N3O3S, the nitro and thia­zolidinone moieties are inclined with respect to the aromatic ring at dihedral angles of 9.57 (16) and 78.42 (4)°, respectively. In the crystal, N—H⋯O hydrogen bonding connects the mol­ecules along the c and a axes to form a two-dimensional polymeric network. A weak S⋯O inter­action [3.2443 (11) Å] and phenyl ring to phenyl ring off-set π⋯π stacking [with centroid–centroid separation of 3.6890 (7) Å and ring slippage of 1.479 Å] link the polymeric chains along the b and a axes, respectively

Pillared two-dimensional metal-organic frameworks based on a lower-rim acid appended calix[4]arene

Solvothermal reactions of the lower-rim functionalized diacid calix[4]arene 25,27-bis(methoxycarboxylic acid)-26,28-dihydroxy-4-tert-butylcalix[4]arene (LH₂) with Zn(NO₃)₂•6H₂O and the dipyridyl ligands 4,4/-bipyridyl (4,4/-bipy), 1,2-di(4-pyridyl)ethylene (DPE) or 4,4/-azopyridyl (4,4/-azopy) afforded a series of 2-D structures of the formulae {[Zn(4,4/-bipy)(L)]•2¼DEF}n (1), {[Zn₂(L)(DPE)]•DEF}n (2) and {[Zn(OH₂)₂(L)(4,4/-azopy)]•DEF}n (3) (DEF = diethylformamide)

New routes towards reutericyclin analogues

A range of N-acylpyrrolo[3,4-c]isoxazoles and derived N-5 acyltetramides has been prepared via a nitrile oxide dipolar cycloaddition approach, as analogues of the acyltetramic acid metabolite reutericyclin, of interest for their antibiotic potential against Gram-positive bacteria including hospital-acquired infections of resistant Clostridium difficile

Blue-Emitting Butterfly-Shaped 1,3,5,9-Tetraarylpyrenes: Synthesis, Crystal Structures, and Photophysical Properties

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Organic Letters (copyright © American Chemical Society) after peer review and technical editing by the publisher. To access the final edited and published work see: http://dx.doi.org/10.1021/ol400265

An Efficient Approach to the Synthesis of Novel Pyrene-Fused Azaacenes

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Organic Letters (copyright © American Chemical Society) after peer review and technical editing by the publisher. To access the final edited and published work see: http://dx.doi.org/10.1021/ol401438

''Potassium potassates'' based on dihydrotriazinide ligands: syntheses, crystal structures, and comparison with other alkali metal dihydrotriazinide compounds

A series of dihydro-s-triazinidopotassium complexes have been synthesised and structurally characterised by X-ray diffraction. Two of them, the sesqui-pyridine solvate 2 and the mono-THF solvate 3, can be classified in formal terms as ''potassium potassates'' in conforming to the structural pattern established previously for the sesqui-THF solvate 1, the first reported 'ate of this type. Formally complex [(R2K)(-)] anions are linked to K+ cations in polymeric, zig-zag chain arrangements. Solvate 3 also possesses a unique RK coordination as a direct result of having fewer solvent Ligands. DMSO analogue 4 deviates from this uniformity in adopting a centrosymmetric, dimeric (OK)(2) ring structure featuring both terminal and bridging DMSO ligands. The dihydro-s-triazinidosodium tris(THF) solvate 5 is found to be a monomer. For comparative purposes, the metal-free, parent triazine molecule 6 has also been subjected to an X-ray crystallographic study: it displays a 1,2-dihydro ring setup as opposed to the 1,4-dihydro alternative existing in the metallo examples. Triazine 6 is also found to form a N-H ... Br bridge in the dimeric structure of the lithium bromide bis (THF) solvate 7, a suspected hydrolysis product from the reaction of dihydro-s-triazinidolithium 8 and magnesium bromide bis(ether) adduct

Sulfimidation of thioether groups—a versatile method for modifying and linking thia/oxa crowns

Reaction of the mixed thioether/ether crowns [9]aneO2S 1, [12]aneO3S 2 and [18]aneO4S2 3 with one mol. equivalent of the aminating agent MSH (o-mesitylsulfonylhydroxylamine) in Et2O results in the formation of the mono-sulfimidated systems {[9]aneO2(SNH2)}+ 1a, {[12]aneO3(SNH2)}+ 2a and {[18]aneO4S(SNH2)}+ 3a, while using two mol. equivalents of MSH with 3 gives the disulfimidium cation {[18]aneO4(SNH2)2}2+ 3b. All of these species have been isolated in good yields as the [mesSO3]- (mes = 2,4,6-Me3C6H2) salts and can be readily converted to the [BPh4]- salts by metathesis with Na[BPh4]. Treatment of 1a or 2a with lithium diisopropylamide (LDA) and N-bromosuccinimide (NBS) at -78 °C, followed by addition of a further equivalent of the parent thia/oxa crown, gives monocationic N-bridged sulfimide bicyclic compounds ( 4 and 5 respectively), in which the crowns are linked by the sulfimidic nitrogen. Reaction of 3a with LDA and NBS leads to formation of the {([18]aneO4S2)N}+ cation 6 which exhibits an intramolecular S–N–S bridge. Crystallographic studies on representative examples of each compound type are described, together with their spectroscopic properties