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Carbohydrates are the major component of biomass and have unique potential as a sustainable source of building blocks for chemicals, materials, and biofuels because of their low cost, ready availability, and stereochemical diversity. With a view to upgrading carbohydrates to access valuable nitrogen‐containing sugar‐like compounds such as aminopolyols, biocatalytic aminations using transaminase enzymes (TAms) have been investigated as a sustainable alternative to traditional synthetic strategies. Demonstrated here is the reaction of TAms with sugar‐derived tetrahydrofuran (THF) aldehydes, obtained from the regioselective dehydration of biomass‐derived sugars, to provide access to cyclic aminodiols in high yields. In a preliminary study we have also established the direct transamination of sugars to give acyclic aminopolyols. Notably, the reaction of the ketose d‐fructose proceeds with complete stereoselectivity to yield valuable aminosugars in high purity.

The regioselective gold‐catalysed hydration of propargylic alcohols to β‐hydroxy ketones can be achieved by diverting the gold‐catalysed Meyer–Schuster rearrangement through the addition of a protic additive with a pK a of 7–9 such as p‐nitrophenol, boric acid or a boronic acid. This provides an interesting alternative to an aldol reaction when combined with the straightforward addition of an alkyne to an aldehyde or ketone. The gold‐catalysed reaction of an electron‐deficient, sterically hindered propargylic alcohol with a boronic acid led to the formation of an unusually stable cyclic boron enolate.

L-Arabinose is an abundant resource available as a waste product of the sugar beet industry. Through use of a hydrazone-based strategy, L-arabinose was selectively dehydrated to form a chiral tetrahydrofuran on a multi-gram scale without the need for protecting groups. This approach was extended to other biomass-derived reducing sugars and the mechanism of the key cyclization investigated. This methodology was applied to the synthesis of a range of functionalized chiral tetrahydrofurans, as well as a formal synthesis of 3R-3-hydroxymuscarine.

A stereoselective synthesis of a ceramide sphingolipid as a potential sex pheromone of the hair crab Erimacrus isenbeckii is reported using diastereoselective alkylation and aldol reactions of butane-2,3-diacetal (BDA) desymmetrised glycolic acid building blocks as the key synthetic steps. © Georg Thieme Verlag Stuttgart.

Conversion of biomass using biocatalysis is likely to become a technology that contributes significantly to the future production of chemical building blocks, materials and transport fuels. Here the synthesis of a value-added chemical from L-arabinose, a major component of the carbohydrates in sugar beet pulp (SBP), in a concise and sustainable manner has been investigated. Biocatalytic conversions using transketolase variants have been developed for the efficient, scalable synthesis of a rare naturally occurring ketoheptose, L-gluco-heptulose, from L-arabinose. New active E. coli TK mutants that readily accept L-arabinose were identified using a versatile colorimetric screening assay and the reaction was performed on a preparative scale.

KESSLER 10 FOR USE IN YOUTH MENTAL HEALTH OUTREACH SERVICES Gareth Furber, PhD, Ann E Crago, Tom D Sheppard, Clive Skene (Clinical Psychology) Health Economics and Social Policy Group, School of Population Health, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, SA, 5000; Bachelor of Nursing Youthlink, Women’s and Children’s Health Network, SA Health, GP Plus Health Care Centre Marion, 10 Milham Street, Oaklands Park, Adelaide, SA, 5046; Registered Nurse (Mental Health) Youthlink, Women’s and Children’s Health Network, SA Health, GP Plus Health Care Centre Marion, 10 Milham Street, Oaklands Park, Adelaide, SA, 5046; Master of Psychology CAMHS Executive, Level 1, 55 King William Road, North Adelaide, SA, 5006 Corresponding Author: E gareth.furber@unisa.edu.au

Acetylcholine activates nicotinic acetylcholine receptors (nAChRs) by binding to an extracellular site located at the interface of two adjacent subunits. In contrast, recent studies have provided evidence that positive allosteric modulators (PAMs) such as TQS (4-(naphthalen-2-yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline-8-sulfonamide) and allosteric agonists such as 4BP-TQS (4-(4-bromophenyl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline-8-sulfonamide) interact at an intrasubunit transmembrane site. Here, we describe the synthesis and pharmacological characterization of a series of chemically related allosteric modulators of the α7 nAChR. Minimal changes in the chemical structure of these compounds have been found to exert profound effects on their pharmacological properties. For example, compounds containing a bromine atom at either the ortho or meta position on the phenyl ring, such as 2BP-TQS (4-(2-bromophenyl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline-8-sulfonamide) and 3BP-TQS (4-(3-bromophenyl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline-8-sulfonamide), rather than at the para position (4BP-TQS), display no allosteric agonist activity but retain PAM activity on α7 nAChRs, demonstrating the importance of the location of the halogen atom on pharmacological properties. Replacement of the bromine atom in 4BP-TQS with either a chlorine [4CP-TQS (4-(4-chloroophenyl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline-8-sulfonamide)] or an iodine atom [4IP-TQS (4-(4-iodoophenyl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline-8-sulfonamide)] results in compounds that have pharmacological properties characteristic of allosteric agonists but display differences in activation rates, in inactivation rates, and in levels of desensitization. In contrast, replacement of the bromine atom in 4BP-TQS with a fluorine atom [4FP-TQS (4-(4-fluorophenyl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline-8-sulfonamide)] generated a compound that lacks allosteric agonist activity but acts a potentiator of responses to acetylcholine. In addition, 4FP-TQS was found to act as an antagonist of responses evoked by allosteric agonists such as 4BP-TQS. These findings provide evidence of the pharmacological diversity of compounds interacting with the allosteric transmembrane site on α7 nAChRs.

The preparation of butane-2,3-diacetal protected glycolic acid and related systems is described together with highly selective alkylation reactions of (R,R) and (S,S) butanediacetal protected glycolic acid. These compounds are readily deprotected to give enantiopure alpha-hydroxyacids, alpha-hydroxyesters or alpha-hydroxyamides by suitable choice of conditions.