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doi: 10.1002/jctb.5030320602pmid: N/A
A review of the structure‐activity relations in aryloxypropanolamine β‐adrenoceptor drugs is presented. The effect of substitution in various parts of the molecule on β1/β2 selectivity and degree of partial agonism is discussed. Cardiac (β1) selectivity is achieved by hydrophilic compounds with either p‐amide substitution in the aryl ring, or a hydrogen bonding group in the amine side chain. Lipophilic compounds with branched chains tend to be β2 selective. Partial agonist activity may also be controlled by hydrogen bonding groups in the side chain and by aromatic substitution. Here 3,4‐dihydroxyl groups give full agonists, mono‐and des‐hydroxy (OH) groups partial agonists. The size of any o‐substituent is critical and a plot of Taft's steric factor versus partial agonism gives a linear relation. By manipulation of the above factors all combinations of selectivity and agonist activity may be achieved.
Behr, Arno; Keim, Wilhelm; Thelen, Gerhard; Scharf, Hans‐Dieter; Ressler, Ingrid
doi: 10.1002/jctb.5030320603pmid: N/A
Norbornadiene derivatives are able to store solar energy under isomerisation to a quadricyclane system. This energy can be liberated by a transition‐metal catalysed back reaction. With methanol as a solvent during the isomerisation of dimethylquadri‐cyclanedicarboxylate I to the dimethylnorbornadienedicarboxylate II the isomeric nortricyclylmethylethers IIIa and IVa are formed as by‐products. In the presence of water the formation of the alcohols IIIb and IVb has been observed. As a result of the side‐reactions observed, it is concluded that this solar‐energy storage system I→II offers no practicability.
Clifford‐King, William; Ferrige, Anthony G.; Torkington, Peter
doi: 10.1002/jctb.5030320604pmid: N/A
The decompositions of ethyleneimine (EI) and its N‐acetyl derivative (AEI) have been studied in aqueous buffers at concentrations down to 1 mM. The course is determined by pH dependence, of two alternative reactions for AEI and of two consecutive reactions for EI. Consistent kinetic systems are presented. One of the reactions of AEI is a hydrolysis to EI, not reported previously. The rate‐determining step for EI decomposition is initial dimerisation to N‐(β‐aminoethyl)‐aziridine.
Caoca, José; Bueno, Julio L.; Sastre, Herminio
doi: 10.1002/jctb.5030320605pmid: N/A
Measurements of the zeta potential of coal suspensions have been carried out by micro‐electrophoresis. The influence of colloidal particles concentration, temperature, pH and ionic strength on two types of Spanish coals have been studied. Experimental results are discussed in terms of the adsorptive properties of coal surface and with regard to the formation of aggregates by coagulation.
Das, Chandra Kumar; Das, Nikhilendu Sekhar
doi: 10.1002/jctb.5030320606pmid: N/A
Oxidation of anthracene to anthraquinone by air/oxygen in the presence of small amounts of nitric acid was studied in the liquid phase. The effects of various process variables (e.g. temperature, flow rate, amount of nitric acid and solvent substrate ratio) were investigated. An attempt was made to minimise the amount of nitric acid. The optimum conversions of anthracene into anthraquinone free from nitro compounds, using air and oxygen was found to be 81.7 and 96.2% respectively with corresponding purities of 98.5% and 99.6%.
Volesky, B.; Yerushalmi, L.; Luong, J. H. T.
doi: 10.1002/jctb.5030320607pmid: N/A
A specially developed temperature control system on a laboratory scale fermenter enabled continuous measurement of the rate of heat production during undisturbed growth of microbial cultures. Apart from being correlated with oxygen uptake rate, the heat of fermentation was established as an additional indicator of metabolic activity. The ‘aerobic respiration’ energetic activity of Candida utilis, Candida lipolytica and Saccharomyces cerevisiae on different carbon substrates was investigated with cultures of the latter species being also studied under the ‘aerobic fermentation’ conditions induced by glucose catabolite repression.
Manchanda, A. C.; Jogdand, V. V.; Karanth, N. G.
doi: 10.1002/jctb.5030320608pmid: N/A
The rheological behaviour of cellulose fermentation broths of Penicillium funiculosum culture has been investigated. The shear stress‐shear rate behaviour is explained satisfactorily by a power law model, although there appear to be small yield stresses, particularly at high substrate concentrations.
Sharma, Durlubh K.; Sahgal, Prakash N.
doi: 10.1002/jctb.5030320609pmid: N/A
Agricultural wastes such as rice husks and sawdust can be used for the manufacture of chemicals including furfural and acetic acid. In the present work the conventional use of superheated steam has been replaced by the use of superheated water in the acidic hydrolysis of rice husk and sawdust. Comparable yields of furfural have been obtained by using superheated water in place of superheated steam in the same temperature and pressure range. This is an attempt to economise the heat requirement and reduce the cost of production of furfural.
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