Herstellung von Aryl-isothiocyanaten aus Arylaminen und Bis-diäthylthiocarbamoylsulfiden

The preparation of aryl-isothiocyanates from aryl-amines and bis-diethylthiocarbamoyl sulfides is reported and mechanisms are proposed for these reactions of thiocarbamoyl derivatives.     

Die Herstellung von Glasfritten aus Pyrexglas

Ohne Zusammenfassung     

Synthese von 3,3-Dimethylperhydro-1,4-diazepin-2,5,7-trionen aus 3-Dimethylamino-2,2-dimethyl-2H-azirin und Malonsäuremonoamiden

Synthesis of 3,3-Dimethylperhydro-1,4-diazepin-2,5,7-triones from 3-Dimethylamino-2,2-dimethyl-2H-azirine and Malonic Acid Monoamides Reaction of the aminoazirine 1 and malonic acid monoamides 5 in CH₃CN yielded triamides of type 6 (Scheme 2), which were transformed to the corresponding phenylthioates 9 by treatment of a solution of 6 and thiophenol in CH₃CN with HCl (Scheme 4). Cyclization of 9 to give the 1,4-diazepin-2,5,7-trione of type 10 was achieved with NaH in toluene at about 90°. It has been shown that 2-oxazolin-5-ones are intermediates in the selective cleavage of the therminal amide function of 6 (Scheme 3).     

Herstellung von erythro-2-Hydroxybernsteinsäure-Derivaten aus Äpfelsäureester. Vorläufige Mitteilung

Preparation for erythro-2-Hydroxy-succinic Acid Derivatives from Malic Esters As a contribution to the much discussed diastereoselective synthesis of enantiomers of open chain compounds, > 90% erythro-selective branching of malic esters by alkylation of the doubly deprotonated derivative 2 (alkoxide-enolate) with methyl, allyl, and benzyl halides in THF at ?78° (→ 3aa, 3ba, 3bb, 3bc , Table 1) is described. A second alkylation (→ 4 ) and addition of 2 to acetone (→ 5 ) are also possible. Cyclization of 2 to the enantiomerically pure trans-epoxides 6 is achieved by treatment with iodine. Cuprate opening of 6b furnishes the same product 3ba obtained from the methylation of 2b , establishing the configurational assignment.     

Nachhaltige Bausteine für die Kunststoff‐Herstellung

Plant oils are currently the principle resource for the production of bio‐based, high performance polymers, such as polyamides. This process is facilitated by giant strides in chemical catalysis and biotechnology, which allows conversion of vegetable oils in “drop‐in” chemical building blocks. These bio‐based polymer building blocks have equivalent chemical and physical properties as well as similar cost structures compared to conventional petrochemical synthesis feedstock. This allows integration of bio‐based resources into industrial production processes without significant adaptations in logistics or process configuration. However, only use of synergies between chemical and biotechnological unit operations will in future provide for sustainable and eco‐efficient process designs. To allow sustainable supply of bio‐oils to a growing chemical industry without a significant impact on food production demands development of alternative bio‐oil sourcing strategies. In this respect the development of processes for the production of microbial oils, which have equivalent chemical properties to their plant counterparts is imperative. One leading option is the biotechnological conversion of agricultural and food waste streams into microbial oils by combining enzymatic hydrolysis and fermentative production using oleaginous organisms, such as yeasts.