摘要:

AbstractAfter the identification of unexpected products formed from methyl dichloro‐acetate and an amino‐sulphonamide during the attempted synthesis of a derivative of 3,4‐dihydro‐2H‐1,2,4‐benzothiadiazine 1,1‐dioxide, unprecedented selective acylation of the sulphonamido group in sulphanilamide was found to occur when esters of activated carboxylic acids were allowed to condense at 25 °C with the sodium salt of sulphanilamide in methanol.The scope of this reaction was examined both with respect to the amino‐sulphonamide and with respect to the ester used as acylating agent. No limitations to the reaction were found among the amino‐sulphonamides examined, each of which was acylated exclusively at the sulphonamido group. Methyl dichloro‐acetate and methyl tricyloroacetate were effective acylating agents, ethyl dichloro‐acetate was less so, and ethyl chloroacetate was ineffective.The mechanisms of the new reaction and of the classical acylation by acyl‐pyridinium ions are discussed and compared, and explanations are offered for the contra‐selectivity of the two reactions.The infrared spectra of theN‐aminoarenesulphonyl‐2, 2‐dichloroacetamides andN‐aminoarenesulphonyl‐2, 2, 2‐trichloroacetamides made by the new method reveal that in many cases these compounds have a zwitterionic structure in the solid state which is lo

ISSN:0375-9210    

DOI:10.1002/jctb.5020230402

出版商:John Wiley&Sons, Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractA general discussion is presented of the effects of hydroxylation pattern upon the structural changes of flavylium salts and their stability at different pH levels. The discussion is based upon the results of spectrometric and polarographic investigations of flavylium salts and incorporates hitherto unpublished data for the anthocyanidin, cyanidin chloride.

ISSN:0375-9210    

DOI:10.1002/jctb.5020230403

出版商:John Wiley&Sons, Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractIn order to test certain ideas which have recently been formulated on the way in which basic lead compounds stabilise polyvinyl chloride against thermal decomposition, the reaction of dry hydrogen chloride with a suspension of white lead in hot di‐2‐ethyl hexyl phthalate was studied by withdrawing samples and examining the solids by X‐ray diffraction. Normal lead phthalate, and an uncharacterised substance which has been called “basic lead chloride X”, were formed initially. Subsequently, this basic lead chloride X was converted to normal lead chloride.The continuous formation of normal lead phthalate in this experiment contrasts with observations made on the crystalline products of stabilising reactions in PVC blends containing basic lead carbonates, and suggests that there are fundamental differences between the reaction mechanisms which prevail in these two systems. It is proposed that the results obtained with PVC blends are best explained in terms of free‐radical mechanisms for thermal decomposition and stabilisation of this polymer, whereas the results obtained in the present experiment can be explained by a simple acid—base type reaction.X‐ray powder diffraction data are tabulated for normal

ISSN:0375-9210    

DOI:10.1002/jctb.5020230404

出版商:John Wiley&Sons, Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractThe optimal control of a fermentation process can be achieved through the parameter optimisation that is based on the quantitative physiology of the fermentation system. One must first identify the most important state and control variables to the production rate of a particular fermentation product. These variables must be measured accurately and monitored continuously for the control of the process. This necessitates a reliable instrumentation system that is compatible with computer interfacing. A specific method of parameter optimisation of a few key variables and a development of a process control scheme for penicillin fermentation are illustrated as an example. In this example, understanding of quantitative physiological aspect of the fermentation process is emphasized. As the understanding of a process is further advanced, any partial process control scheme can be gradually expanded into an ultimate automatic control of the overall fermentation process. As the complexity of the process control scheme and the multiplicity of the control variables increase, the use of a computer system becomes an economic necessity for the control and monitoring of fermentation process. An example of how this might be done is shown in an information flow‐sheet for a computer‐coupled fermentation system. Other examples of industrial use of computers for fermentation facilities are sh

ISSN:0375-9210    

DOI:10.1002/jctb.5020230405

出版商:John Wiley&Sons, Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractAmylose readily dissolves in dimethyl sulphoxide (DMSO) to give clear colourless solution which is stable and forms a convenient stock amylose solution for amylase determinations. Dimethyl sulphoxide has no inhibitory effect on different amylolytic enzymes at the concentrations required for enzyme assay.

ISSN:0375-9210    

DOI:10.1002/jctb.5020230406

出版商:John Wiley&Sons, Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractGrowth ofBacillus polymyxaand high activities of amylase were obtained in media containing starch and peptone. Of the metals of biological significance, calcium and manganese had the most beneficial effects on enzyme yields. Control of pH was critical for the establishment of conditions which yielded maximum levels of enzyme. The appearance of highest amylase activity in culture supernatant liquors during the stationary phase of growth was not due to autolysis; intracellular levels of the enzyme were shown to be very low throughout the fermentation. When the organism was grown in a medium containing a low level of starch (1%, w/v), amylase activity was low during the logarithmic phase of growth but rose rapidly in the culture liquor when growth ceased. Negligible activity was detected when the organism was grown in a medium which contained excess starch. This amylase therefore appears to be a true extracellular enzyme, in the accepted sense. It is produced in response to exhaustion of the carbon source from the medium.

ISSN:0375-9210    

DOI:10.1002/jctb.5020230407

出版商:John Wiley&Sons, Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractA chemically defined medium for cultivation ofBacillus maceransis reported. Growth rates and cyclodextrin glycosyltransferase (CGT) titres obtained were similar to those obtained using media containing potato extract. The proteins in supernatant fluids from a batch culture were separated by disc electrophoresis and results obtained showed that CGT was produced after growth ceased, in agreement with results of activity measurements. The maximum growth rate in the chemostat considerably exceeded that in batch culture; this anomalous effect is unexplained. High CGT titres were produced at low dilution rates (0.03 to 0.05 h−1) but residual starch was present at higher dilution rates and CGT synthesis was repressed. Enzyme titres obtained in chemostat cultures atD= 0.03 h−1using defined medium containing 13 g starch/1 were 2.75 times greater than the maximum obtainable by batch cultivation and about 20 times greater than those reported by other workers using medium containing diced potato and CaCO3. A two‐stage chemostat cultivation was performed using dilution rates of 0.1 h−1and 0.033 h−1in the first and second stages, respectively. The CGT activity in the second stage increased by 57 per cent when a maintenance feed of starch was supplied at 0.08 g g−1dry biomass h−1. Only negligible CGT titres were obtained when a dilution rate of 0.5 h−1was used in the first stage. For reasons not understood, DM medium would not support biomass yields greater than 5 g 1−1. This limitation was not due to production of an inhibitor, or to deficiency of N, Fe, Zn, Mn, t

ISSN:0375-9210    

DOI:10.1002/jctb.5020230408

出版商:John Wiley&Sons, Ltd    

年代:1973

数据来源: WILEY

ISSN:0375-9210    

DOI:10.1002/jctb.5020230401

出版商:John Wiley&Sons, Ltd    

年代:1973

数据来源: WILEY