Characterisation of the first authenticated organomercury hydroxide, 4-Me₂NC₆H₄HgOH

4-Me₂NC₆H₄HgOH was prepared from 4-Me₂NC₆H₄HgOAc. Full characterisation showed that it crystallises as discrete molecules, the first example of a true organomercury hydroxide in the solid state. The structures of 4-Me₂NC₆H₄HgOAc and (4-Me₂NC₆H₄)₂Hg are also discussed. 4-Me₂NC₆H₄HgOH has been characterised spectroscopically and crystallographically as a true organomercury hydroxide

cyclo-Tetra-μ-oxido-tetrakis[3-nitro-4-hydroxyphenylarsenic(III)]

The title compound, [As₄O₄(C₆H₄NO₃)₄], has an eight-membered As₄O₄ ring with a slightly twisted boat-chair conformation. The aryl groups complete the threefold coordination for each As atom. Each OH group forms a strong intramolecular O-H⋯O hydrogen bond to the adjacent NO₂ group, with only weak C-H⋯O, O⋯As [3.036 (6)-3.184 (6) Å] and O⋯O [2.921 (10)-2.930 (10) Å] interactions between tetramers

New complexes with M-Si-O or M-Si-S linkages (M = Fe or Co)

Ph2XSiFe(CO)2Cp [X = p-tolylS (1a), MeO (1b)] and Ph[2-MeOC6H4]XSiFe(CO)2Cp [X = Cl (2a), OMe (2b)] have been fully characterised, including X-ray crystal structure determinations for 1a, 1b and 2a. None of the examples showed any tendency for migration of the X groups from silicon to iron, with elimination of silylene. However very ready loss of the X groups was seen in the electrospray mass spectra, suggesting formation of the cationic silylene-iron complex ions is favoured. This was especially so for 2a and 2b, where intramolecular stabilisation of the silicon centre from the 2-OMe group is possible.The stable siloxane O[SiPh2{Co(CO)4}]2 was also characterised; the X-ray crystal structure analysis shows a Si-O-Si bond angle of 153°

Anomalous reaction of an aryl silane with Co₂ (CO)₂; characterisation of Me ₂NC₆H₄Si[Co(CO)₄][OCCo₃(CO)₉]₂

Reaction of Me₂NC₆H₄SiH₃ with Co₂(CO)₈ gave Me₂NC₆H₄Si[Co(CO)₄][OCCo₃(CO)₉]₂ which was shown to have one –Co(CO)₄ group and two –OCCo₃(CO)₉ cluster units bonded to the silicon atom

Novel polyoxometalates: Is antimony the new molybdenum?

Polyoxometalates based on Mo, W or V have been known for a long time and present a diverse range of structures, with the [XMo₁₂O₄₀]ⁿ⁻ Keggin ions (X = P, Si ,…) perhaps the best known.¹ They are still subject to intense research with >4000 papers published in the past five years. Following on from our study² of aryl arsonic acids RAsO₃H₂, which are straightforward molecular species based on four-coordinate As(V), we became interested in the corresponding antimony compounds. Although aryl stibonic acids of nominal formula RSbO₃H₂ have been known for over 100 years,³ their composition has remained uncertain, as they form only amorphous solids, have complicated titration behaviour and only limited solubility. The presumption has been that they are polymeric, based on 5- or 6-coordinate Sb with Sb-O-Sb linkages, though direct evidence is sparse.⁴ Recently, it has been shown by Beckman that if very bulky R groups are used, then relatively simple dimers such as (2,6-Mes₂C₆H₃Sb₂O₂(OH)₄(Mes=mesityl) can be isolated, but these represent a special case.

Tris(tert-butylisonitrile)hexacarbonyl- 3-ethylidyne-triangulo-tricobalt(I)(3 Co-Co)

The title molecule, [Co3(C2H3)(C5H9N)3(CO)6] or [Co3(3-CCH3)(CNtBu)3(CO)6], lies on a threefold rotation axis. The three isonitrile ligands each occupy an equatorial site on each of the three Co atoms. The average Co-Co bond length is 2.4769 (6) Å. The tert-butyl groups are disordered over two orientations, with site occupancies of ca 0.6:0.4

A low-toxicity method for the separation of lanosterol and dihydrolanosterol from commercial mixtures

We describe an inexpensive, low-toxicity and high-yielding method for the production of pure lanosterol and dihydrolanosterol from the commercially available mixture. Optimum conditions are presented for the one-pot production of the intermediate 24,25 vicinal diol of lanosterol acetate (via either epoxidation or hydroxyhalogenation) which is readily separated from the unreacted dihydrolanosterol acetate. The lanosterol diol can then be converted to pure (>97%) lanosterol. Hypophosphorous acid was used for both the conversion of the epoxide to the diol, and as a catalyst for the hydroxyhalogenation by N-halosuccinimides of the olefinic bond

Efficient routes to epimerically-pure side-chain derivatives of lanosterol

A technically simple route is described to individual epimers of side-chain derivatives of lanosterol (3-hydroxy-5-lanosta-8,24-diene). Epimerically pure 24,25-epoxy-, 24,25-dihydroxy- and 24-bromo-25-hydroxy-lanosterol have been prepared in good yield from commercial (50-60%) lanosterol. Hypophosphorous acid was used as a catalyst for the cohalogenation of the 24(25) bond and also for the efficient conversion of 24,25-epoxy- and 24-bromo-25-hydroxylanosterol to epimerically pure 24(R) or 24(S)-24,25-dihydroxylanosterols

Manufacturing Barriers to Biologics Competition and Innovation

As finding breakthrough small-molecule drugs gets harder, drug companies are increasingly turning to “large molecule” biologics. Although biologics represent many of the most promising new therapies for previously intractable diseases, they are extremely expensive. Moreover, the pathway for generic-type competition set up by Congress in 2010 is unlikely to yield significant cost savings. In this Article, we provide a fresh diagnosis of, and prescription for, this major public policy problem. We argue that the key cause is pervasive trade secrecy in the complex area of biologics manufacturing. Under the current regime, this trade secrecy, combined with certain features of FDA regulation, not only creates high barriers to entry of indefinite duration but also undermines efforts to advance fundamental knowledge. In sharp contrast, offering incentives for information disclosure to originator manufacturers would leverage the existing interaction of trade secrecy and the regulatory state in a positive direction. Although trade secrecy, particularly in complex areas like biologics manufacturing, often involves tacit knowledge that is difficult to codify and thus transfer, in this case regulatory requirements that originator manufacturers submit manufacturing details have already codified the relevant tacit knowledge. Incentivizing disclosure of these regulatory submissions would not only spur competition but it would provide a rich source of information upon which additional research, including fundamental research into the science of manufacturing, could build. In addition to provide fresh diagnosis and prescription in the specific area of biologics, the Article contributes to more general scholarship on trade secrecy and tacit knowledge. Prior scholarship has neglected the extent to which regulation can turn tacit knowledge not only into codified knowledge but into precisely the type of codified knowledge that is most likely to be useful and accurate. The Article also draws a link to the literature on adaptive regulation, arguing that greater regulatory flexibility is necessary and that more fundamental knowledge should spur flexibility. A vastly shortened version of the central argument that manufacturing trade secrecy hampers biosimilar development was published at 348 Science 188 (2015), available online