Abstract A series of tetrazole-linked dibenzo[b,f][1,4]oxazepines is synthesized through a short sequence involving an Ugi tetrazole reaction. The intermediate undergoes potassium carbonate mediated SNAr cyclization, followed by oxidation to afford the target tricyclic heterocyclic scaffold. optimization, scope and limitations this two-step efficient methodology are investigated. 1000-member li...

Cu-catalyzed Pd-free Sonogashira coupling has been proposed as a straightforward and convenient route to valuable steroidal enynes. A biligand catalyst system based on Ph3P and TMEDA has been designed. The protocol was utilized for the efficient coupling of iodosteroids with diverse terminal alkynes and 1-trimethylsilylalkynes. A possible role of an auxiliary ligand as a phase-transfer catalyst...

1. Carbonic anhydrase was measured in tissues of silkmoths, Hyalophora cecropia, reared on either a wheatgerm-based synthetic diet or wild cherry foliage in feeding fifth-instar larvae, throughout the larval-pupal transformation and in newly ecdysed pupae. 2. Carbonic anhydrase activity was present in fat body, midgut and intgeumentary epithelial cells, but not in haemolymph, cuticle or the int...

Additives per kg: Vitamins – E672 vitamin A 5,000 IU; vitamin C 50 mg; E671 vitamin D3 250 IU; 3a700 vitamin E 25 mg. Trace elements E5 Manganese (manganese chelate of glycine hydrate) 7,000 mg; E6 Zinc (zinc chelate of glycine hydrate) 6,500 mg; E1 Iron (iron chelate glycine hydrate) 6,000mg; E4 Copper (copper chelate of glycine hydrate) 4,000 mg; E2 Iodine (potassium iodide) 5 mg; E8 Selenium...

Aromatic methyl ketones and cyclic asymmetric ketones underwent hydrophosphorylation with P-stereogenic H-P species in the presence of potassium carbonate to produce P,C-stereogenic tertiary α-hydroxyl phosphinates in excellent yields with up to 99 : 1 dr. The diastereoselectivity was induced by a reversible conversion of less stable stereomer of product to that of a more stable one via an equi...

The permeability of the upper jejunum to water, calcium, potassium, sodium and chloride was measured in the immature pullet and then in the laying hen before and during egg-shell calcification by an in vivo perfusion procedure. Jejunal calcium permeability was constant throughout egg formation. Thus, the increase of net absorption during shell calcification was not due to enhanced mucosal capac...

Microwave-assisted solvent-free modification of pectin was successfully accomplished, consisting in the esterification of several fatty acids by pectin alcoholic functions. The reaction was performed by simply mixing the reagents with a catalytic amount of the inorganic base (potassium carbonate) and irradiating the obtained mixture with microwaves for a short time (3-6 min). The replacement of...

To prepare activated carbons with a high porosity and low ash content from pyrolyzed rice husk, the method of KOH or K2CO3 solution leaching after CO2 activation was investigated. The effects of KOH or K2CO3 concentration and leaching time on the yield, ash content, and textural properties of the activated carbon were studied, and the activated carbon prepared under the best conditions was char...

The effects of ball milling parameters, namely, the ball-to-powder mass ratio and milling speed, on the synthesis of (K0.5Na0.5)NbO3 nanopowders by high-energy ball milling method from a stoichiometric mixture containing Na2CO3, K2CO3, and Nb2O5 were investigated in this paper. The results indicated that the single crystalline phase of (K0.5Na0.5)NbO3 was received in as-milled samples synthesiz...

[18F]Fluoride was trapped from [18O]water in high yield by ion exchange on a microporous carbon prepared by controlled oxidation to produce a cationic surface with an exchange capacity of about 350 microequiv/g. The [18F]fluoride could be recovered by displacement with aqueous K2CO3. The cationic carbon offered a dimensionally rigid matrix of high thermal stability. It was characterized with re...