Recent Optimization Highlights of the Georgywood Process

Abstract

Alternative procedures to the industrial process by which Georgywood ® is presently prepared on a multiton scale have been investigated. these give the crucial homomyrcene precursor 5a and target compound 1 with greatly improved selectivities. homomyrcene 5a was prepared with much better yield and selectivity by converting methylgeraniol 4 into an allylic carbonate, followed by a solvent-free palladium-catalyzed 1,4-elimination. in the final 1,5-diene cyclization, excellent selectivities were achieved by replacing Brønsted acid h 3 Po 4 by meAlcl 2 . this requires preparation, safety measures and an in-situ conversion of stoichiometric amounts of the pyrophoric Lewis acid. recently, an in situ preparation of meAlcl 2 from Alme 3 and its catalytic use became possible.

Purification and biochemical characterisation of a novel glutamate decarboxylase from rice bran

“…Die Entwicklung von Methangas wurde im Vergleich zur ursprünglichen, stöchiometrischen Vorschrift minimiert, wodurch die Sicherheit des Prozesses verbessert wurde 255a. 257, 258 Bei einer neueren Variante, die auch zur Umsetzung in größerem Maßstab geeignet ist, wurde Methacrylnitril ( 464 ) als Dienophil verwendet (Schema ) 259. Die Phosphorsäure‐vermittelte Cyclisierung des Addukts 465 und die anschließende Umsetzung mit Methylmagnesiumbromid führten in hoher Ausbeute und Selektivität zu Georgywood ( 462 ).…”

Determination of Sudan IV in hot chilli powder with luminol/dissolved oxygen chemiluminescence system

“…The evolution of gaseous methane was minimized compared to the original stoichiometric protocol, thereby improving the overall safety of the process 255a. 257, 258 A recently disclosed variant, also amenable to scale‐up, featured the use of methacrylonitrile ( 464 ) as the dienophile (Scheme ) 259. Phosphoric acid mediated cyclization of adduct 465 , followed by treatment with methyl magnesium bromide gave Georgywood ( 462 ) with high yield and selectivity.…”

Cyclopropanation with Dibromomethane under Grignard and Barbier Conditions

“…g Crude yield, 24% after distillation, not optimized. Scheme 5 Sequential ester cleavage/cyclopropanation of allyl esters and carbonates 9a,b 20,21 An interesting extension of the tandem alkylation/cyclopropanation method is the S N 2¢ allylic substitution and cyclopropanation of vinyloxiranes (Procedure 4). Alkyllithium reagents are known to open isoprene oxide 11a without additives by 1,3-allylic substitution, giving mainly Z-configurated 4-alkyl-2-methylbut-2-en-1-ols.…”